ORCID Profile
0000-0002-0347-643X
Current Organisations
University of Sheffield
,
University of Tasmania
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Publisher: Elsevier BV
Date: 08-2009
Publisher: Springer Science and Business Media LLC
Date: 12-1995
DOI: 10.1007/BF00118871
Publisher: MDPI AG
Date: 18-01-2022
DOI: 10.3390/MICROORGANISMS10020202
Abstract: Amoebic gill disease (AGD) is a significant health issue for Atlantic salmon farmed in a marine environment. While the disease is currently managed using freshwater or hydrogen peroxide baths, there is a need to develop other treatments. The aims of this study were to examine the effect of salinity (0 ppt and 35 ppt) and temperature (3 °C and 15 °C) on attachment and survival of Neoparamoeba perurans in vitro over short exposure times (15 min and 2 h) and to assess the efficacy of reduced temperature (3 °C) as treatment for Atlantic salmon affected by AGD. In vitro freshwater 3 °C was at least as effective as freshwater 15 °C and the attachment was significantly lower after 2 h in freshwater 3 °C than freshwater 15 °C. In vivo there was no difference between the fish treated with freshwater 15 °C for 2 h or freshwater 3 °C. This study showed that despite exposure to low temperature reducing attachment of N. perurans to their substrate in vitro, 15 min cold-water bath treatment was not more effective at reducing AGD in Atlantic salmon than current commercial 2 h freshwater bath.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.MARPOLBUL.2019.110493
Abstract: Melanisation of muscle, observed as black pigmentation of the normally white flesh, has been reported in sand flathead from Tasmania and investigated in this study. There was a significant difference in the presence of melanised muscle in sand flathead from two sites within the Tamar Estuary (northern Tasmania), with higher proportion of sand flathead from Deceitful Cove with this condition. Presence of melanisation was not related to length or weight of the fish. No parasitic infections were detected in the muscles of the affected sand flathead. However, concentration of zinc in melanised regions of muscle in the affected fish was significantly higher, about 1.7 to 1.8 times, than non-melanised regions of muscle in the same fish. Furthermore, the concentration of zinc in melanised regions of affected fish was on average about 2.0 times higher when compared to muscle of unaffected fish that had no melanised spots.
Publisher: Wiley
Date: 04-2003
DOI: 10.1046/J.1365-2761.2003.00452.X
Abstract: Amoebic gill disease is the main disease affecting the salmonid industry in Tasmania, but no information on the distribution of the causative pathogen, Neoparamoeba pemaquidensis, in the aquatic environment is available. This pilot study aimed to determine temporal and spatial distributions of paramoebae species in the water column, using an immuno-dot blot technique. Water s les were collected from inside fish cages at various depths (0.5, 5.5 and 11.0 m) in both summer and winter, as well as various distances (0, 0.5, 240, 280, 750 and 1100 m) away from the sea cage and farming site. Paramoebae densities were estimated using the most probable number technique (MPN). Temperature, salinity, dissolved oxygen, turbidity, nitrite and nitrates, and bacterial counts were measured for each water s le. Data were analysed using a residual maximum likelihood test and significant associations between paramoebae densities and environmental factors were analysed. Results showed that densities were significantly higher in summer (P = 0.017), at 5.5 m depth (P = 0.029), and reduced to the lowest density at 1100 m away from the cage sites (P = 0.008). Bacterial counts, turbidity and temperature were found to be significantly associated with paramoebae densities.
Publisher: Elsevier BV
Date: 11-2016
Publisher: Wiley
Date: 2000
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.EJOP.2014.07.004
Abstract: Some of the species from the genus Neoparamoeba, for ex le N. perurans have been shown to be pathogenic to aquatic animals and thus have economic significance. They all contain endosymbiont, Perkinsela amoebae like organisms (PLOs). In this study we investigated phylogenetic ambiguities within the Neoparamoeba taxonomy and phylogenetic congruence between PLOs and their host Neoparamoeba to confirm the existence of a single ancient infection/colonisation that led to cospeciation between all PLOs and their host Neoparamoeba. DNA was extracted and rRNA genes from host amoeba and endosymbiont were lified using PCR. Uncertainties in the Neoparamoeba phylogeny were initially resolved by a secondary phylogenetic marker, the internal transcribed spacer 2 (ITS2). The secondary structure of ITS2 was reconstructed for Neoparamoeba. The ITS2 was phylogenetically informative, separating N. pemaquidensis and N. aestuarina into distinct monophyletic clades and designating N. perurans as the most phylogenetically ergent Neoparamoeba species. The new phylogenetic data were used to verify the tree topologies used in cophylogenetic analyses that revealed strict phylogenetic congruence between endosymbiotic PLOs with their host Neoparamoeba. Strict congruence in the phylogeny of all PLOs and their host Neoparamoeba was demonstrated implying that PLOs are transmitted vertically from parent to daughter cell.
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.VETPAR.2015.02.019
Abstract: A survey of blood fluke, Cardicola forsteri, infection in ranched southern bluefin tuna, Thunnus maccoyii, was undertaken over three farming seasons, from March 2004 to September 2006. Analyses of covariance and logistic regression were used to explore the effects of company, year, season, time in culture, and condition index on intensity, abundance and prevalence of blood fluke infection. Average prevalence of blood fluke infection was 62.64% over the period of the survey. Average intensity was 6.20 (± 0.57) fluke per infected host and the average abundance was 3.70 (± 0.57) fluke per host. Year did not influence mean intensity or abundance although a significant decrease in prevalence in 2005 was evident. Tuna harvested in winter had a significantly greater abundance and prevalence of blood fluke than the tuna harvested in autumn. No effect of intensity or abundance of infection was observed on the condition of the infected tuna. A universal factor in explaining variation in C. forsteri intensity, abundance and prevalence was company. Differences in infection levels between tuna from different companies may be related to differences in husbandry measures employed on each farm, or due to different average sizes of tuna farmed by each of the companies, or due to the location of the operations.
Publisher: Australian Museum
Date: 28-05-2014
Publisher: Inter-Research Science Center
Date: 21-11-2006
DOI: 10.3354/DAO073043
Abstract: To study the concentration effects of the bacterium Winogradskyella sp. on amoebic gill disease (AGD), Atlantic salmon Salmo salar were pre-exposed to 2 different doses (10(8) or 10(10) cells 1(-1)) of Winogradskyella sp. before being challenged with Neoparamoeba spp. Exposure of fish to Winogradskyella sp. caused a significant increase in the percentage of AGD-affected filaments compared with controls challenged with Neoparamoeba only however, these percentages did not increase significantly with an increase in bacterial concentration. The results show that the presence of Winogradskyella sp. on salmonid gills can increase the severity of AGD.
Publisher: Elsevier BV
Date: 2011
Publisher: Wiley
Date: 27-10-2004
DOI: 10.1111/J.1365-2761.2004.00575.X
Abstract: Barramundi, Lates calcarifer (Bloch), were immunized with an experimental Vibrio harveyi bacterin via intraperitoneal injection, immersion and anal intubation. Both specific and non-specific immune parameters were measured to compare responses to bacterin after delivery by various methods. Elevated antibody activities in sera were found in all treatment groups with barramundi injected intraperitoneally displaying significantly higher antibody activity than the other groups. In addition, there was evidence of memory induction with a heightened antibody response in the intraperitoneally injected group only. Bacteriostatic assays indicated activity against V. harveyi in the sera of all bacterin-treated groups again this activity was significantly higher in the intraperitoneally injected groups. There was no enhancement noted in head kidney macrophage phagocytic activity or in serum lysozyme levels.
Publisher: Wiley
Date: 04-12-2020
DOI: 10.1111/JFD.13317
Publisher: Elsevier BV
Date: 09-2001
DOI: 10.1016/S0145-305X(01)00024-6
Abstract: Detailed immunological studies of the teleosts have been h ered by a lack of antibodies against cell-specific markers. Furthermore, where antibodies have been raised, in many instances they have been found to be species-specific. In comparison, many monoclonal and polyclonal antibodies exist with specificities for mammalian proteins and glycoproteins that effectively differentiate leukocyte sub-populations. In this study, we have tested a panel of 54 commercial antibodies against human and murine cell surface receptors for their ability to bind leukocytes isolated from the peripheral blood of snapper (Pagrus auratus). From this panel, one antibody, A452, which is specific for the intracytoplasmic tail of the epsilon (epsilon) chain of the T cell receptor-associated CD3 complex (CD3epsilon) bound to a subpopulation of peripheral blood leukocytes. Mutually exclusive counterstaining was observed when this antibody was used in conjunction with a monoclonal anti-snapper immunoglobulin antibody. This suggests that A452 may be binding to putative snapper T cells.
Publisher: Elsevier BV
Date: 07-2002
Publisher: MDPI AG
Date: 22-07-2020
Abstract: Amoebic gill disease (AGD), caused by the amoeba Neoparamoeba perurans, has led to considerable economic losses in every major Atlantic salmon producing country, and is increasing in frequency. The most serious infections occur during summer and autumn, when temperatures are high and poor dissolved oxygen (DO) conditions are most common. Here, we tested if exposure to cyclic hypoxia at DO saturations of 40–60% altered the course of infection with N. perurans compared to normoxic controls maintained at ≥90% DO saturation. Although hypoxia exposure did not increase initial susceptibility to N. perurans, it accelerated progression of the disease. By 7 days post-inoculation, amoeba counts estimated from qPCR analysis were 1.7 times higher in the hypoxic treatment than in normoxic controls, and cumulative mortalities were twice as high (16 ± 4% and 8 ± 2%), respectively. At 10 days post-inoculation, however, there were no differences between amoeba counts in the hypoxic and normoxic treatments, nor in the percentage of filaments with AGD lesions (control = 74 ± 2.8%, hypoxic = 69 ± 3.3%), or number of lamellae per lesion (control = 30 ± 0.9%, hypoxic = 27.9 ± 0.9%) as determined by histological examination. Cumulative mortalities at the termination of the experiment were similarly high in both treatments (hypoxic = 60 ± 2%, normoxic = 53 ± 11%). These results reveal that exposure to cyclic hypoxia in a diel pattern, equivalent to what salmon are exposed to in marine aquaculture cages, accelerated the progression of AGD in post-smolts.
Publisher: Elsevier BV
Date: 06-2014
DOI: 10.1016/J.FSI.2014.03.034
Abstract: This study investigated the use of a recombinant protein of Neoparamoeba perurans, the causative agent of Amoebic gill disease (AGD), as an immunogen to generate systemic and mucosal antibody responses against the parasite. Genes encoding N. perurans homologs of mannose-binding protein (MBP) from Acanthamoeba spp. have been identified. From these, a Neoparamoeba MBP - like EST has been identified and produced as a recombinant fusion protein. Attachment of N. perurans to the gill might be reduced by antibody-mediated interference of this protein, but this is dependent on the presence and level of functional antibodies in the mucus. Fish were immunized with the protein via i.p. injection with Freund's complete adjuvant (FCA) and serum and skin mucus s les were collected before and after immunization. Antibodies (IgM) present in s les were characterized via Western blot and their levels measured with an ELISA. The immunization was able to induce a systemic IgM response 8 weeks after primary exposure and a mucosal response 4 weeks post initial immunization, which were specific to the recombinant protein but not to antigens obtained from crude amoebic preparations. However, adherence of the antibodies to the parasite was observed using immunocytochemistry, and both, serum and skin mucus IgM, were able to bind the surface of formalin-fixed N. perurans. This finding may contribute to further research into the development of a vaccine for AGD.
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.FSI.2013.01.026
Abstract: Temperature is known to influence inflammatory signalling in mammals, but far less understood in fish. The aim of the present study was to explore the potential effects of temperature on innate immune signalling in head kidney and leukocyte populations of the economically important southern bluefin tuna through the identification and utilization of gene expression targets in vitro. Here, we identified the mRNA sequences of five potential inflammatory mediators - TNFα (1 and 2), IL-1β, IL-8, and Cox2 - and demonstrate induction of four - TNFα (2), IL-1β, IL-8, and Cox2 - following LPS stimulation of both peripheral blood leukocytes and head kidney homogenates in vitro by real-time quantitative PCR. Comparison of transcriptional expression in cultures held at 18 and 25 °C (both within the presumed natural temperature range of this heterothermic species) showed accelerated transcription of cytokines TNFα, IL-1β and IL-8 following LPS stimulation at 25 °C in both tissue types. Peak induction reached comparable levels for each transcript at both temperatures during the 24 h test period with only limited (if any) protraction in expression resulting from cold temperature (18 °C) incubation. Partial mRNA sequences were also identified for both the constitutively expressed and heat inducible chaperone proteins Hsc70 and Hsp70, and 24 h incubation at 25 °C was sufficient to induce Hsp70 transcription in leukocyte but not in head kidney cell populations. Taken together these findings suggest that temperature exerts influence in the timing but not the degree of an innate inflammatory response in bluefin tuna and that different cell populations have differential responsiveness to heat shock in this heterothermic species. Further, LPS stimulation failed to induce Hsp70 at either incubation temperature in leukocytes whereas 25 °C incubation caused Hsp70 up-regulation in leukocytes with or without the presence of LPS. This suggests that Hsp70 does not play a direct role in immune responsiveness for this species and that an environmental temperature of 25 °C in excess of 24 h initiates a cellular stress response in blood cells of this organism. Lastly, a strong correlation between Hsp70 and IL-8 transcriptional expression was observed following LPS/heat shock stimulation of leukocytes and five potential heat shock response elements were subsequently identified on the gene promoter region of IL-8 indicating that heat shock co-activation of this chemokine previously identified in mammals is also likely present in fish.
Publisher: Elsevier BV
Date: 02-2009
Publisher: Elsevier BV
Date: 09-2020
Publisher: Wiley
Date: 30-05-2022
DOI: 10.1111/JFD.13660
Abstract: Urinary calculi are observed in some cultured marine fish larvae and may negatively impact larval health and survival. This study assessed urinary calculi in striped trumpeter Latris lineata larvae from hatching to 28 days post-hatching (dph). The prevalence of urinary calculi was variable over time and ranged from 15% to 50%, whereas the average size of calculi increased with larval age. Urinary calculi were semi-translucent, light cream to white colour with irregular morphology and a uniform internal structure. The calculi resulted in pressure atrophy causing a distended epithelium of the urinary bladder of fish with calculi. The calculi were predominantly formed of calcium hydrogen phosphate (CaHPO
Publisher: Wiley
Date: 2005
DOI: 10.1111/J.1365-2761.2004.00600.X
Abstract: A total of 18 Neoparamoeba strains were characterized both morphologically and using the SSU rRNA gene sequences as molecular markers. Nine were isolated from gills of farmed Atlantic salmon, Salmo salar L., six from sediments s led in areas of sea-cage farms and three from net material of sea-cages. The newly obtained sequences extended substantially the dataset of Neoparamoeba strains available for phylogenetic analyses, which were used to infer taxonomic relatedness among 32 strains morphologically assigned to this genus. In addition to the N. pemaquidensis and N. aestuarina clades, phylogenetic analyses clearly distinguished a third clade with sequences from six strains. Members of this clade are characterized as representatives of a new species, N. branchiphila n. sp. The diagnostic primers for the identification of this species are introduced.
Publisher: Elsevier BV
Date: 07-2000
DOI: 10.1016/S0141-1136(00)00253-1
Abstract: Non-specific immune response of greenback flounder, Rhombosolea tapirina, exposed to contaminated marine sediments was examined. Reference sediments from Port Sorell and contaminated sediments from Deceitful Cove, Tasmania, Australia were investigated. Hatchery-reared flounder were exposed to reference sediment, contaminated sediment or contaminated sediment and diet for 6 weeks. Phagocytic capacity and lysozyme response in flounder were examined on cessation of exposure trial. Significant differences were found in phagocytic capacity and lysozyme response between treatments. Exposure to contaminated sediment, irrespective of diet or benthic disturbance elicited inhibition of phagocytic efficiency in flounder. Disturbance of contaminated sediment stimulated lysozyme activity. The immune response in flounder indicates potential immunotoxicity of sediment from Deceitful Cove.
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.FSI.2014.11.031
Abstract: Amoebic gill disease (AGD) is the main health problem for the salmon industry in Tasmania, Australia and is now reported in most salmon producing countries. Antibody and gene expression responses to the pathogen, Neoparamoeba perurans, have been studied independently following primary exposure however, the effects of sequential reinfection, which can often occur during net-pen culture of salmon, remain unclear. The association between the transcription of immunoglobulin (Ig) and their systemic and mucosal antibody levels in regards to AGD is unknown. Herein, we assessed the antibody responses as well as Ig transcription in the gills of Atlantic salmon infected only once and also sequentially with N. perurans. After four successive AGD challenges, no significant differences in plasma or skin mucus levels of IgM were observed between AGD-naïve and challenged fish. However, IgM gene expression in gill lesions of AGD-affected fish increased up to 31 d after infection, while no changes in IgT, TCR and CD8 transcription were observed. Changes at IgM transcription level did not match the lack of antibody response in mucus, which is possibly explained by weak correlations existing between protein and mRNA abundances in cells and tissues. In the second experiment, which investigated Ig responses to AGD at the transcriptional as well as antibody production level in salmon after a single infection, the levels of serum or skin mucus IgM antibody were not affected and no changes in the IgM or IgT transcription were induced.
Publisher: Public Library of Science (PLoS)
Date: 25-08-2011
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.FSI.2014.06.025
Abstract: The external surfaces of fish, such as gill and skin, are covered by mucus, which forms a thin interface between the organism and water. Amoebic gill disease (AGD) is a parasitic condition caused by Neoparamoeba perurans that affects salmonids worldwide. This disease induces excessive mucus production in the gills. The host immune response to AGD is not fully understood, and research tools such as genomics and proteomics could be useful in providing further insight. Gill and skin mucus s les were obtained from Atlantic salmon (Salmo salar) which were infected with N. perurans on four successive occasions. NanoLC tandem mass spectrometry (MS/MS) was used to identify proteins in gill and skin mucus of Atlantic salmon affected by AGD. A total of 186 and 322 non-redundant proteins were identified in gill and skin mucus respectively, based on stringent filtration criteria, and statistics demonstrated that 52 gill and 42 skin mucus proteins were differentially expressed in mucus s les from AGD-affected fish. By generating protein-protein interaction networks, some of these proteins formed part of cell to cell signalling and inflammation pathways, such as C-reactive protein, apolipoprotein 1, granulin, cathepsin, angiogenin-1. In addition to proteins that were entirely novel in the context in the host response to N. perurans, our results have confirmed the presence of protein markers in mucus that have been previously predicted on the basis of modified mRNA expression, such as anterior gradient-2 protein, annexin A-1 and complement C3 factor. This first proteomic analysis of AGD-affected salmon provides new information on the effect of AGD on protein composition of gill and skin mucus. Future research should focus on better understanding of the role these components play in the response against infection with N. perurans.
Publisher: Elsevier BV
Date: 05-2011
Publisher: Elsevier BV
Date: 12-2013
Publisher: Elsevier BV
Date: 05-2011
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 04-2003
Abstract: This study investigated the effects of prolonged administration of a commercial beta-glucan based immunostimulant preparation, EcoActiva, in the form of a feed supplement, on non-specific immune parameters and the growth rate of snapper (Pagrus auratus). Fish held at a temperature representing either summer or winter conditions, were s led periodically and assayed for head kidney macrophage activity via in vitro superoxide production, and classical and alternative complement activity. Fish were also weighed monthly and the growth rate determined. Fish fed on a diet supplemented with EcoActiva and held at the winter temperature had a significant enhancement of macrophage superoxide anion production upon stimulation with phorbol myristate acetate (PMA), and this increased activity was maintained throughout the trial. Macrophage activity in fish fed the supplemented diet and held at the summer temperature was also increased. However, EcoActiva failed to increase either classical or alternate complement activity. Most significantly EcoActiva resulted in an increase in growth rates of the fish held at the winter temperature as compared to the control fish, although no difference was seen between the groups held at the summer temperature. These results suggest that routine incorporation of beta-glucan preparations like EcoActivaduring winter may enhance macrophage function and growth rates at a time of increased disease susceptibility and little or no growth.
Publisher: MDPI AG
Date: 30-03-2021
DOI: 10.3390/MICROORGANISMS9040710
Abstract: Amoebic Gill Disease (AGD) severely affects salmonid mariculture due to fish losses and costs associated with management of the disease. Continued research into management solutions, including new treatments and vaccine development, is highly important for the future of salmonid production worldwide. This requires both in vitro (both pathogen only and host-pathogen models) and in vivo (disease challenge) testing. Challenge models are still widely varied, in particular with regard to: infection methods (cohabitation or immersion), source of the pathogen (isolated from infected fish or cultured), infectious dose, environmental conditions (in particular temperature) and the endpoints across experimental treatment and vaccine studies which makes comparisons between studies difficult. This review summarises in vitro assays, the challenge methods and endpoints used in studies of experimental treatments and vaccines for AGD.
Publisher: Elsevier BV
Date: 09-2001
DOI: 10.1016/S0145-305X(01)00024-6
Abstract: Detailed immunological studies of the teleosts have been h ered by a lack of antibodies against cell-specific markers. Furthermore, where antibodies have been raised, in many instances they have been found to be species-specific. In comparison, many monoclonal and polyclonal antibodies exist with specificities for mammalian proteins and glycoproteins that effectively differentiate leukocyte sub-populations. In this study, we have tested a panel of 54 commercial antibodies against human and murine cell surface receptors for their ability to bind leukocytes isolated from the peripheral blood of snapper (Pagrus auratus). From this panel, one antibody, A452, which is specific for the intracytoplasmic tail of the epsilon (epsilon) chain of the T cell receptor-associated CD3 complex (CD3epsilon) bound to a subpopulation of peripheral blood leukocytes. Mutually exclusive counterstaining was observed when this antibody was used in conjunction with a monoclonal anti-snapper immunoglobulin antibody. This suggests that A452 may be binding to putative snapper T cells.
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.IJPARA.2015.04.005
Abstract: Amoebic Gill Disease affects farmed salmonids and is caused by Neoparamoeba perurans. Clonal cultures of this amoeba have been used for challenge experiments, however the effect of long-term culture on virulence has not been investigated. Here we show, using in vitro and in vivo methods, that a clone of N. perurans which was virulent 70 days after clonal culture lost virulence after 3 years in clonal culture. We propose that this is related either to the lack of attachment to the gills or the absence of an extracellular product, as shown by the lack of cytopathic effect on Chinook salmon embryo cells. The avirulent clonal culture of N. perurans allowed us to propose two potential virulence mechanisms/factors involved in Amoebic Gill Disease and is an invaluable tool for host-pathogen studies of Amoebic Gill Disease.
Publisher: Routledge
Date: 05-2015
Publisher: Elsevier BV
Date: 2021
DOI: 10.1016/J.IJPARA.2021.06.004
Abstract: Infections by blood flukes (Cardicola spp.) are considered the most significant health issue for ranched bluefin tuna, a major aquaculture industry in Japan and Australia. The host-parasite interfaces of trematodes, namely their teguments, are particularly rich in carbohydrates, which function both in evasion and modulation of the host immune system, while some are primary antigenic targets. In this study, histochemistry and mass spectrometry techniques were used to profile the glycans of Cardicola forsteri. Fluorescent lectin staining of adult flukes indicates the presence of oligomannose (Concanavalin A-reactive) and fucosylated (Pisum sativum agglutinin-reactive) N-glycans. Additionally, reactivity of succinylated wheat germ agglutinin (s-WGA) was localised to several internal organs of the digestive and monoecious reproductive systems. Glycan structures were further investigated with tandem mass spectrometry, which revealed structures indicated by lectin reactivity. While O-glycans from these adult specimens were not detectable by mass spectrometry, several oligomannose, paucimannosidic, and complex-type N-glycans were identified, including some carrying hexuronic acid and many carrying core xylose. This is, to our knowledge, the first glycomic characterisation of a marine platyhelminth, with broader implications for research into other trematodes.
Publisher: Inter-Research Science Center
Date: 2005
DOI: 10.3354/DAO067061
Abstract: Marine sediment s les collected from various sites at 2 Atlantic salmon farms in Tasmania were analysed for the presence of Neoparamoeba sp., an amoeba associated with amoebic gill disease (AGD) in farmed Atlantic salmon. Environmental variables of the sediment layer at each site, including redox potential and sulphide concentration, were measured and the general biological condition assessed by video observation. Sediments and environmental data were collected on 4 occasions at each site over a 12 mo period. Neoparamoeba sp. was detected in populations of amoebae recovered by culture from all sites and in 50% of all sediment s les taken. There was evidence of a seasonal influence on the presence of the amoeba, but this was different at each farm. No Neoparamoeba sp. was recovered from any sites at Farm 1 during the winter of 2002 whereas at Farm 2 this was the case for the summer of 2003. There appeared to be no relationship between the presence of Neoparamoeba sp., salmon farming activities and environmental parameters.
Publisher: Center for Open Science
Date: 26-05-2021
Abstract: ObjectivesTo test whether demographic variation in vaccine hesitancy can be explained by differences in trust and healthcare experiences.DesignCross-sectional study.SettingData collected online by Ipsos MORI in April 2021.ParticipantsData collected from 4885 UK-resident adults, of whom 3223 had received the invitation to be vaccinated against the novel coronavirus. The remainder were excluded. 1629 included participants identified as female and 1594 as male. 234 identified as belonging to other than white ethnic groups while 2967 identified as belonging to white ethnic groups.Primary and secondary outcome measuresUptake of coronavirus vaccination.ResultsMembership of an other than white ethnic group (AOR = 0.53, 95% CI [0.35, 0.84], p = .005) and age (AOR = 1.61, 95% CI [1.39, 1.87], p & .001 for a 1 SD change from the mean) were the only statistically significant demographic predictors of vaccine uptake. After controls for NHS healthcare experiences and trust in government, scientists, and medical professionals, the effect associated with membership of an other than white ethnic group appears more marginal (AOR = 0.61, 95% CI [0.38, 1.01], p = .046), while the effect associated with age remains virtually unchanged. Exploratory analysis suggests that NHS healthcare experiences mediate 24% (95% CI [8%, 100%], p = .024) of the association between ethnicity and uptake, while trust mediates 94% (95% CI [56%, 100%], p .001) of the association between NHS healthcare experiences and uptake.ConclusionsMembers of other than white ethnic groups report inferior NHS healthcare experiences, which may explain the lower trust that they report in government, scientists, and medical professionals. However, this does not fully explain the ethnic gap in coronavirus vaccination uptake.Trial registrationThe data collection and confirmatory analysis were pre-registered with the Center for Open Science (osf.io/56txk).Strengths and limitations of this studyThe s le was large, providing high statistical power, and was designed for representativeness of the UK adult population Standard measures of trust and healthcare experiences were used, providing confidence that these variables have been measured robustly However, it was not possible to obtain a probability s le, and there was limited representation within the s le both of people who did not take up the invitation to be vaccinated and of members of other than white ethnic groups
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.SCITOTENV.2019.06.180
Abstract: Few ecotoxicological studies exist on the accumulation and effects of rare earth elements (REEs) in fish, particularly on Arctic species. In southwest Greenland, there are currently several advanced exploration REE mining projects. The aim of this study was to investigate accumulation of REEs in native fish species. Juvenile arctic chars, Salvelinus alpinus, were pulse-exposed to cerium (Ce), lanthanum (La) and yttrium (Y) using an in-situ flow-through system over a period of 15 days. Results showed that the arctic char accumulated most REEs in the gills > liver > muscle. We also demonstrated the ability of the arctic char to rapidly excrete the REEs throughout the experiment, where levels of post exposure accumulation also declined throughout the period. These results demonstrate the importance of further studies on accumulation of REE in the arctic char native to the site of future mining operations. Long-term exposure will most likely result in accumulation of REEs in arctic char, and the effects and accumulation patterns of this should be explored further.
Publisher: Elsevier BV
Date: 05-2007
Publisher: Wiley
Date: 10-2016
DOI: 10.1111/JFD.12311
Abstract: Flavobacterium psychrophilum is the causative agent of bacterial coldwater disease (BCWD), which has a major impact on salmonid aquaculture globally. An Enterobacter species, C6-6, isolated from the gut of rainbow trout, Oncorhynchus mykiss (Walbaum), has been identified as a potential probiotic species providing protection against BCWD. This study examined the effects of alginate microencapsulation on the protective efficacy of C6-6 against BCWD in vivo when administered to rainbow trout fry orally or by intraperitoneal (IP) injection. Viable C6-6 bacteria were microencapsulated successfully, and this process (microencapsulation) did not significantly deteriorate its protective properties as compared to the administration of non-microencapsulated C6-6 bacteria. Both oral and IP delivery of C6-6 achieved significantly better protection than control treatments that did not contain C6-6 bacteria. The highest relative percent survival (RPS) resulted from IP delivery (71.4%) and was significantly greater than the highest oral RPS (38.6%). Successful intestinal colonization was not critical to protective effects of C6-6. The study showed that C6-6 administration, with or without encapsulation, was a viable choice for protecting fry from BCWD especially when administered intraperitoneally.
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.VETPAR.2008.02.027
Abstract: Tuna farming off Port Lincoln, Australia, involves catching wild 2-4-year-old southern bluefin tuna in summer and then fattening for periods of 2-8 months. As fresh product is not available year-round, the feasibility of maintaining tuna for longer periods was trialled, including over a summer season, when temperatures may exceed 24 degrees C. As the rates of growth and reproduction in ectoparasites of fishes are usually most rapid during warm temperatures, parasite epizootics at this time may adversely affect the health of tuna. We collected epidemiological data on burdens of metazoans on the gills of tuna from the time of stocking in April 2005 through to final harvest in August 2006 (N=220). We document an epizootic of the copepod Pseudocycnus appendiculatus, characterised by a significant increase in both prevalence and mean intensity in the first winter, followed by a decline in these parameters over the next 12 months. This epizootic pattern appears to be independent of seasonal changes in temperature. For two other species, a second copepod (Euryphorus brachypterus) and a polyopisthocotylean flatworm (Hexostoma thynni), there were no clearly discernible trends in infections. As the high water temperatures over the summer period did not lead to increased infections of any species of gill parasites, we conclude that they do not threaten the feasibility of farming of Thunnus maccoyii.
Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 03-2000
Publisher: Elsevier BV
Date: 11-2011
Publisher: Wiley
Date: 10-2002
Publisher: Wiley
Date: 12-2001
Publisher: MDPI AG
Date: 19-11-2019
Abstract: Neoparamoba perurans, is the aetiological agent of amoebic gill disease (AGD), a disease that affects farmed Atlantic salmon worldwide. Multilocus sequence typing (MLST) and Random Amplified Polymorphic DNA (RAPD) are PCR-based typing methods that allow for the highly reproducible genetic analysis of population structure within microbial species. To the best of our knowledge, this study represents the first use of these typing methods applied to N. perurans with the objective of distinguishing geographical isolates. These analyses were applied to a total of 16 isolates from Australia, Canada, Ireland, Scotland, Norway, and the USA. All the s les from Australia came from farm sites on the island state of Tasmania. Genetic polymorphism among isolates was more evident from the RAPD analysis compared to the MLST that used conserved housekeeping genes. Both techniques consistently identified that isolates of N. perurans from Tasmania, Australia were more similar to each other than to the isolates from other countries. While genetic differences were identified between geographical isolates, a BURST analysis provided no evidence of a founder genotype. This suggests that emerging outbreaks of AGD are not due to rapid translocation of this important salmonid pathogen from the same area.
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.ENVRES.2016.12.007
Abstract: Fourhorn sculpins (Myoxocephalus quadricornis) and shorthorn sculpins (Myoxocephalus scorpius) have been considered suitable local bioindicators for environmental monitoring studies in the Arctic. Because these species share many characteristics, data from the two species have previously been pooled when assessing marine metal contamination. A chemical and histological study was conducted on fourhorn and shorthorn sculpins collected around a contaminated lead-zinc mine at East Greenland to investigate whether there were any differences in the residues of metals, histopathology and parasites in liver and gills between the two sculpin species. The results demonstrated that concentrations of copper (Cu), zinc (Zn), mercury (Hg) and lead (Pb) were significantly higher in the fourhorn sculpins (p<0.001) while there were no significant differences for arsenic (As) or cadmium (Cd). Furthermore, density of blood vessel fibrosis (p=0.028), prevalence and density of chondroplasia (p=0.002 and p=0.005, respectively), number of mucin-containing mucous cells (p<0.001) and chloride cells (p<0.001) and mean intensity of colonial Peritricha (p<0.001) were significantly higher in fourhorn sculpin. Based on these results we suggest that pooling the two species when conducting environmental assessments is not recommended as it can lead to incorrect conclusions. We propose that a larger study investigating the biological effects of zinc-lead mining in Greenland is needed.
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.FSI.2013.12.013
Abstract: Amoebic gill disease (AGD) is a disease caused by the ectoparasite Neoparamoeba perurans which affects several cultured marine fish worldwide. The characterisation of pro-inflammatory and immune related genes at the mRNA level in AGD-affected Atlantic salmon gills was performed at 10 days post-inoculation using 2D quantitative RT-PCR, a method of mapping transcriptional responses in tissues. The genes of interest were IL-1β, TNF-α, TCR-α chain, CD8, CD4, MHC-IIα, MHC-I, IgM and IgT. A significant increase in expression of the mRNA of all the genes was observed in the gills of AGD-affected fish. Contrary to previous studies, our data suggest that the parasite, N. perurans, elicits a classical inflammatory response in the gills of AGD-affected fish and indicates that the mRNA expression of immune genes within gill lesions misrepresents the cellular immune response in the gills during AGD.
Publisher: Wiley
Date: 20-04-2010
Publisher: MDPI AG
Date: 15-08-2023
Abstract: Fish aquaculture is a rapidly expanding global industry, set to support growing demands for sources of marine protein. Enhancing feed efficiency (FE) in farmed fish is required to reduce production costs and improve sector sustainability. Recognising that organisms are complex systems whose emerging phenotypes are the product of multiple interacting molecular processes, systems-based approaches are expected to deliver new biological insights into FE and growth performance. Here, we establish 14 erse layers of multi-omics and clinical covariates to assess their capacities to predict FE and associated performance traits in a fish model (Oncorhynchus tshawytscha) and uncover the influential variables. Inter-omic relatedness between the different layers revealed several significant concordances, particularly between datasets originating from similar material/tissue and between blood indicators and some of the proteomic (liver), metabolomic (liver), and microbiomic layers. Single- and multi-layer random forest (RF) regression models showed that integration of all data layers provide greater FE prediction power than any single-layer model alone. Although FE was among the most challenging of the traits we attempted to predict, the mean accuracy of 40 different FE models in terms of root-mean square errors normalized to percentage was 30.4%, supporting RF as a feature selection tool and approach for complex trait prediction. Major contributions to the integrated FE models were derived from layers of proteomic and metabolomic data, with substantial influence also provided by the lipid composition layer. A correlation matrix of the top 27 variables in the models highlighted FE trait-associations with faecal bacteria (Serratia spp.), palmitic and nervonic acid moieties in whole body lipids, levels of free glycerol in muscle, and N-acetylglutamic acid content in liver. In summary, we identified subsets of molecular characteristics for the assessment of commercially relevant performance-based metrics in farmed Chinook salmon.
Publisher: Elsevier BV
Date: 06-2007
DOI: 10.1016/J.FSI.2006.08.019
Abstract: The association between major histocompatibility (MH) polymorphism and the severity of infection by amoebic gill disease (AGD) was investigated across 30 full sibling families of Atlantic salmon. In iduals were challenged with AGD for 19days and then their severity of infection scored by histopathological examination of the gills. Fish were then genotyped for the MH class I (Sasa-UBA) and MH class II alpha (Sasa-DAA) genes using polymorphic repeats embedded within the 3' untranslated regions of the Sasa-UBA and Sasa-DAA genes. High variation in the severity of infection was observed across the s le material, ranging from 0% to 85% gill filaments infected. In total, seven Sasa-DAA-3UTR and ten Sasa-UBA-3UTR marker alleles were identified across the 30 families. A significant association between the marker allele Sasa-DAA-3UTR 239 and a reduction in AGD severity was detected. There was also a significant association found between AGD severity and the presence of two Sasa-DAA-3UTR genotypes. While the associations between MH allele/genotypes and AGD severity reported herein may be statistically significant, the small s le sizes observed for some alleles and genotypes means these associations should be considered as suggestive and future research is required to verify their biological significance.
Publisher: Wiley
Date: 05-2005
DOI: 10.1111/J.1365-2761.2005.00625.X
Abstract: Infections by the gill fluke Zeuxapta seriolae are a serious concern for sea cage aquaculture of kingfish, Seriola lalandi. The present study aimed to determine the pathophysiological effects of a progressive infection with Z. seriolae and the effects of treatment with hydrogen peroxide. For the progression of infection study, infected fish were taken from a sea cage farm, treated to remove parasites and then infected by cohabitation with heavily infected fish. S les were taken at 2-week intervals for 8 weeks. Infection intensity peaked at 4 weeks post-infection (mean intensity 565.9) and the number of mature worms (2 mm fixed length or larger) peaked at 6 weeks post-infection. Attachment of Z. seriolae appeared to cause little localized pathology however, the occurrence of hyperplastic lamellae increased as the infection progressed. Haemoglobin concentrations were negatively correlated with Z. seriolae intensity and were lower than controls at 4 weeks (35.8% decrease) and 6 weeks (57.4% decrease) post-infection. Blood lactate concentration and plasma osmolality increased throughout the course of infection. For the effect of treatment experiment, groups of infected and non-infected fish were s led either before or after treatment with hydrogen peroxide. Treated fish from both infected and uninfected groups had increased plasma lactate, osmolality and pH compared with pre-treatment groups. Treatment with hydrogen peroxide appeared to have acute effects on fish health but the magnitude (e.g. lactate, osmolality) and extent of the effects (e.g. haemoglobin) was much less than that caused by chronic infection with Z. seriolae.
Publisher: Elsevier BV
Date: 03-2009
Publisher: PeerJ
Date: 25-07-2023
DOI: 10.7717/PEERJ.15763
Abstract: Aporocotylid blood flukes Cardicola forsteri and C. orientalis are an ongoing health concern for Southern Bluefin Tuna (SBT), Thunnus maccoyii , ranched in Australia. Therapeutic application of praziquantel (PZQ) has reduced SBT mortalities, however PZQ is not a residual treatment therefore reinfection can occur after the single treatment application. This study documents the epidemiology of Cardicola spp. infection in ranched SBT post treatment over three ranching seasons (2018, 2019 and 2021). Infection prevalence (percentage of SBT affected) and intensity (parasite load) was determined by adult fluke counts from heart, egg counts from gill filaments and the use of specific quantitative polymerase chain reaction (qPCR) for detection of C. forsteri and C. orientalis ITS-2 DNA in SBT hearts and gills. SBT Condition Index decreased as intensity of Cardicola spp. DNA in SBT gills increased, suggesting blood fluke infection had a negative effect on SBT growth (Spearman’s r = −0.2426, d.f. = 138, p = 0.0041). Prevalence and intensity of infection indicated PZQ remained highly effective at controlling Cardicola spp. infection in ranched SBT, 10 years after PZQ administration began in this industry. Company A had the highest prevalence and intensity of Cardicola spp. infection in 2018, and Company G had the highest in 2019. No consistent pattern was seen in 2021. Overall, intensity of infection did not increase as ranching duration increased post treatment. Results from this study improve our knowledge of the biology of blood flukes and helps the SBT industry to modify or design new blood fluke management strategies to reduce health risks and improve performance of SBT.
Publisher: Elsevier BV
Date: 07-1999
Publisher: Elsevier BV
Date: 05-2019
Publisher: Inter-Research Science Center
Date: 2005
DOI: 10.3354/DAO067061
Abstract: Marine sediment s les collected from various sites at 2 Atlantic salmon farms in Tasmania were analysed for the presence of Neoparamoeba sp., an amoeba associated with amoebic gill disease (AGD) in farmed Atlantic salmon. Environmental variables of the sediment layer at each site, including redox potential and sulphide concentration, were measured and the general biological condition assessed by video observation. Sediments and environmental data were collected on 4 occasions at each site over a 12 mo period. Neoparamoeba sp. was detected in populations of amoebae recovered by culture from all sites and in 50% of all sediment s les taken. There was evidence of a seasonal influence on the presence of the amoeba, but this was different at each farm. No Neoparamoeba sp. was recovered from any sites at Farm 1 during the winter of 2002 whereas at Farm 2 this was the case for the summer of 2003. There appeared to be no relationship between the presence of Neoparamoeba sp., salmon farming activities and environmental parameters.
Publisher: Wiley
Date: 03-2004
DOI: 10.1111/J.1365-2761.2004.00526.X
Abstract: Gross pathological assessment of amoebic gill disease (AGD) is the only non-destructive, financially viable method for rapid and broad-scale disease management of farmed Atlantic salmon, Salmo salar L., in Tasmania. However, given the presumptive nature of this diagnosis, the technique has been considered questionable. This study investigated the degree of conformity between clinical signs and histological lesions observed in a commercial setting. Three groups of Atlantic salmon (n = 42, 100 and 100, respectively) were collected from various farm sites in southern Tasmania between December 2001 and April 2003. Micro-stereoscopic analysis showed that grossly affected tissue regions correspond to areas of hyperplastic lamellar fusion, generally in association with attached Neoparamoeba sp. Agreement between gross signs of AGD and histopathological diagnosis was compared. Kappa analysis indicated moderate to good agreement between methods (kappa = 0.52-0.74). In idual cases of disagreement were further scrutinized and several factors were found to influence the level of agreement between the two methods. Stage of disease development, lesions derived from other pathogens, assessor interpretation/experience, s ling methods, histological technique and/or experience were potential confounding factors. It was concluded that clinical diagnosis is acceptable as a farm-monitoring tool only. Removal of grossly affected tissue and subsequent histological examination is recommended to improve diagnostic accuracy.
Publisher: Wiley
Date: 11-1997
Publisher: Springer Science and Business Media LLC
Date: 07-2004
DOI: 10.1007/S00244-003-3030-9
Abstract: Previous work has suggested that the ratio of copper residues to zinc in the gills of rainbow trout may indicate short-term exposure to increased levels of waterborne copper. However, the effect of exposure to a combination of increased copper and zinc concentrates in the water column was unknown. We exposed rainbow trout to 8 +/- 2 microg L(-1), 40 +/- 2 microg L(-1) and 90 +/- 9 microg L(-1) of waterborne copper and 21 +/- 3 microg L(-1), 129 +/- 40 microg L(-1), and 202 +/- 40 microg L(-1) of waterborne zinc in a 2-factor experiments and gill copper and zinc residues were examined. Other gill parameters analyzed included the concentrations of calcium, magnesium, sodium, and potassium, liver copper and zinc concentrations and plasma copper, calcium, sodium, and potassium are also reported here. Copper residues in the gill filaments were significantly higher in the highest level of copper exposure (high Cu, 4.06 microg g(-1) low Cu 2.41 microg g(-1) 0 Cu 2.01 microg g(-1) P = 0.001), whereas no differences were seen in zinc concentrations at any treatment level. Gill sodium and plasma calcium concentrations were also decreased at the highest waterborne copper concentrations. Although copper-zinc ratios in the gills were significantly different between the highest and lowest copper treatments (P = 0.002, F = 6.59), copper-sodium and copper-magnesium ratios were more sensitive to waterborne copper exposure (P = 0.001, F = 17.91 and P = 0.002, F = 15.45, respectively). These copper-metal ratios may be better indicators of copper loading in the water column.
Publisher: Inter-Research Science Center
Date: 2005
DOI: 10.3354/DAO067055
Abstract: The relationship between salmonid gill bacteria and Neoparamoeba sp., the aetiological agent of amoebic gill disease (AGD) was determined in vivo. Fish were ided into 4 groups and were subjected to following experimental infections: Group 1, amoebae only Group 2, Staphylococcus sp. and amoebae Group 3, Winogradskyella sp. and amoebae Group 4, no treatment (control). Fish (Groups 1, 2 and 3) were exposed to potassium permanganate to remove the natural gill microflora prior to either bacterial or amoebae exposure. AGD severity was quantified by histological analysis of gill sections to determine the percentage of lesioned filaments and the number of affected lamellae within each lesion. All amoebae infected groups developed AGD, with fish in Group 3 showing significantly more filaments with lesions than other groups. Typically lesion size averaged between 2 to 4 interlamellar units in all AGD infected groups. The results suggest that the ability of Neoparamoeba sp. to infect filaments and cause lesions might be enhanced in the presence of Winogradskyella sp. The possibility is proposed that the prevalence of more severe AGD is due to the occurrence of Winogradskyella sp. at high concentrations on the gills.
Publisher: Elsevier BV
Date: 02-2006
DOI: 10.1016/J.VETIMM.2005.08.026
Abstract: Amoebic gill disease (AGD) is characterised by the association of Neoparamoeba sp. with hyperplastic gill tissue of affected fishes, however, the identity and role of host cells associated with AGD lesions are not known. Here, we investigated cells with an immunological role that were associated with AGD lesions by locating cellular MHC class II beta chain. A tank housing Atlantic salmon (Salmo salar) was inoculated with Neoparamoeba sp., and MHC class II beta chain expression in the gills was qualitatively assessed by immunohistochemistry. In AGD-naïve control fish, MHC class II+ cells were detected basolateral to the interlamellar epithelium as well as upon the interlamellar and secondary epithelium. In the gills of AGD affected fish MHC class II+ cells were observed in both affected and unaffected tissue. Within AGD lesions, numerous MHC class II+ cells were present and these cells exhibited variable levels of expression suggesting that like mammals, MHC class II expression is highly regulated. The presence of MHC class II+ cells within gill lesions is indicative of immune cell trafficking and these cells could contribute in an antigen presentation capacity to the development of an antibody response in fish chronically affected by AGD.
Publisher: Wiley
Date: 03-2007
Publisher: Wiley
Date: 10-2003
DOI: 10.1046/J.1365-2761.2003.00496.X
Abstract: Amoebic gill disease (AGD) affects the marine culture phase of Atlantic salmon, Salmo salar L., in Tasmania. Here, we describe histopathological observations of AGD from smolts, s led weekly, following transfer to estuarine/marine sites. AGD was initially detected histologically at week 13 post-transfer while gross signs were not observed for a further week post-transfer. Significant increases (P < 0.001) in the proportion of affected gill filaments occurred at weeks 18 and 19 post-transfer coinciding with the cessation of a halocline and increased water temperature at the cage sites. The progression of AGD histopathology, during the s ling period, was characterized by three phases. (1) Primary attachment/interaction associated with extremely localized host cellular alterations, juxtaposed to amoebae, including epithelial desquamation and oedema. (2) Innate immune response activation and initial focal hyperplasia of undifferentiated epithelial cells. (3) Finally, lesion expansion, squamation-stratification of epithelia at lesion surfaces and variable recruitment of mucous cells to these regions. A pattern of preferential colonization of amoebae at lesion margins was apparent during stage 3 of disease development. Together, these data suggest that AGD progression was linked to retraction of the estuarine halocline and increases in water temperature. The host response to gill infection with Neoparamoeba sp. is characterized by a focal fortification strategy concurrent with a migration of immunoregulatory cells to lesion-affected regions.
Publisher: Elsevier BV
Date: 03-2019
Publisher: Magnolia Press
Date: 17-06-2015
DOI: 10.11646/ZOOTAXA.3973.2.8
Abstract: Two species of Glossobius Schioedte & Meinert, 1883 are known from Australia: Glossobius anctus Bruce & Bowman, 1989 and Glossobius impressus (Say, 1818), the latter recorded here for the first time from Australia and southern Africa. Glossobius ogasawarensis Nunomura, 1994 is here placed in synonymy with Glossobius auritus Bovallius, 1885 whereas Glossobius crassa (Dana, 1853) is removed from synonymy with G. auritus and placed into nomen dubium. Glossobius arimae Nunomura, 2001 is transferred to the genus Ceratothoa Dana, 1852. A key to the species of Glossobius is presented.
Publisher: Elsevier BV
Date: 06-2012
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 2002
Publisher: Hindawi Limited
Date: 10-06-2010
Publisher: Hindawi Limited
Date: 12-2001
Publisher: Brill
Date: 2006
Publisher: Wiley
Date: 28-05-2004
Publisher: Elsevier BV
Date: 02-2017
Publisher: Elsevier BV
Date: 08-2013
Publisher: Inter-Research Science Center
Date: 16-07-2015
DOI: 10.3354/AEI00137
Publisher: Wiley
Date: 05-2005
DOI: 10.1111/J.1365-2761.2005.00629.X
Abstract: Farmed Southern bluefin tuna (SBT) were examined for parasites. S les of harvest fish, mortalities and some fish showing clinical signs of disease were investigated. Targeted screening was conducted for a scuticociliate, Uronema nigricans, the myxosporean Kudoa sp. and a sanguinicolid digenean, Cardicola forsteri. General parasitological investigation revealed a erse parasite community of didymozoid digeneans, two species of copepods, a polyopisthocotylean monogenean and larval cestodes. Targeted screening for U. nigricans exposed a low prevalence, most probably due to a lack of sensitivity in the test method. Few of the parasites examined pose a risk to the health of farmed SBT.
Publisher: Wiley
Date: 1997
Publisher: Brill
Date: 2014
DOI: 10.1163/15685403-00003315
Abstract: Ichthyoxenus puhi (Bowman, 1962) is reported for the first time from Mauritius on the host Gymnothorax griseus (Lacépède, 1803), expanding its distribution from Hawaii to the western Indian Ocean. I. puhi is characterized by its oval-shaped body, well-developed posterior lobes on the pereonites, lateral ends of pleonites longer than pereonite 7, pleotelson wider than long, pereopod 4 to 7 with a protruding merus, and a distinct lobe on the proximolateral surface of the basis.
Publisher: BMJ
Date: 08-05-2019
DOI: 10.1136/BMJSPCARE-2018-001749
Abstract: To examine whether use of a hand-held fan (‘fan’) improves breathlessness and increases physical activity. A secondary exploratory analysis using pooled data from the fan arms of two feasibility randomised controlled trials in people with chronic breathlessness: (1) fan and activity advice vs activity advice, (2) activity advice alone or with the addition or the ‘calming hand’, or the fan, or both. Descriptive statistics and regression analysis to explore patient characteristics associated with benefit (eg age, sex, diagnosis, general self-efficacy). Forty-one participants were allocated the fan (73 years (IQR 65–76, range 46–88), 59% male, 20 (49%) chronic obstructive pulmonary disease (COPD), three (7%) heart failure, three (7%) cancer). Thirty-five (85%) reported that the fan helped breathing, and 22 (54%) reported increased physical activity. Breathlessness benefit was more likely in older people, those with COPD and those with a carer. However, due to the small s le size none of these findings were statistically significant. Those with COPD were more likely to use the fan than people with other diagnoses (OR 5.94 (95% CI 0.63 to 56.21, p=0.120)). These exploratory data support that the fan helps chronic breathlessness in most people and adds new data to indicate that the fan is perceived to increase people’s physical activity. There is also a signal of possible particular benefits in people with COPD which is worthy of further study.
Publisher: Elsevier BV
Date: 02-2001
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.FSI.2015.03.016
Abstract: Amoebic gill disease (AGD) affects salmonids during the marine grow-out phase in the Tasmanian industry and in other major salmonid producing countries. During the period post-transfer to seawater, the bacterial condition yersiniosis can also cause high levels of mortality in Atlantic salmon grown in Tasmania, in addition to the hatchery outbreaks. The recombinant protein r22C03, a mannose-binding protein-like (MBP-like) similar to attachment factors of other amoebae, was tested as a vaccine candidate against AGD in a large scale challenge trial. Fish were immunised with r22C03 combined with FCA via intraperitoneal (i.p.) injection, and given a booster five weeks later by either i.p. injection (RP group) or by a dip-immersion (mRP). Fish were then challenged twice with Neoparamoeba perurans: the initial challenge 16 weeks after primary immunisation was terminated due to presence of ulcerative lesions in the skin of salmon the second challenge was carried out after five weeks of treatment with oxytetracycline. These skin lesions might have been associated with a concurrent infection with Yersinia ruckeri, which was detected by real-time qPCR in serum of a large proportion of moribund and survivor fish after the AGD challenge. Before and during the N. perurans infection, levels of antibodies against r22C03 were measured by ELISA in serum, skin mucus and supernatant from skin and gill explants. For the second challenge, the average size of AGD lesions was recorded from histology sections and survival curves were obtained. Before AGD challenge, r22C03 induced antibody responses in serum and explants with both vaccination strategies. At the end of the challenge, levels of antibodies were lower than before challenge irrespective of treatment. Both vaccinated groups presented increased serum antibody responses, while only mRP presented antibody responses in skin mucus, and no significant antibody responses were measured in the explants. Antibodies did not confer protection to N. perurans infection, as no difference was observed in the survival curves of the vaccinated and control groups, and there was no effect on the gill lesion size. The concurrent yersiniosis infection probably represented more closely infection patterns observed in commercial settings. However, it could have interfered with the survival results and with the ability of the fish to respond to the amoebae infection.
Publisher: American Physiological Society
Date: 06-2006
DOI: 10.1152/PHYSIOLGENOMICS.00320.2005
Abstract: Neoparamoeba spp. are hizoic amoebae with the capacity to colonize the gills of some marine fish, causing AGD. Here, the gill tissue transcriptome response of Atlantic salmon ( Salmo salar L.) to AGD is described. Tanks housing Atlantic salmon were inoculated with Neoparamoeba spp. and fish s led at time points up to 8 days postinoculation (pi.). Gill tissues were taken from AGD-affected fish, and a DNA microarray was used to compare global gene expression against tissues from AGD-unaffected fish. A total of 206 genes, representing 190 unique transcripts, were reproducibly identified as up- or downregulated in response to Neoparamoeba spp. infection. Informative transcripts having GO biological process identifiers were grouped according to function. Although a number of genes were placed into each category, no distinct patterns were observed. One Atlantic salmon cDNA that was upregulated in infected gill relative to noninfected gill at 114 and 189 h pi. showed significant identity with the Xenopus, mouse, and human anterior gradient-2 (AG-2) homologs. Two Atlantic salmon AG-2 mRNA transcripts, designated asAG-2/1 and asAG-2/2, were cloned, sequenced, and shown to be predominantly expressed in the gill, intestine, and brain of a healthy fish. In AGD-affected fish, differential asAG-2 expression was confirmed in s les used for microarray analyses as well as in AGD-affected gill tissue taken from fish in an independent experiment. The asAG-2 upregulation was restricted to AGD lesions relative to unaffected tissue from the same gill arch, while p53 tumor suppressor protein mRNA was concurrently downregulated in AGD lesions. Differential expression of p53-regulated transcripts, proliferating cell nuclear antigen and growth arrest and DNA damage-inducible gene-45β (GADD45β) in AGD lesions, suggests a role for p53 in AGD pathogenesis. Thus AGD may represent a novel model for comparative analysis of p53 and p53-regulated pathways.
Publisher: Elsevier BV
Date: 12-1997
Publisher: Canadian Science Publishing
Date: 10-2014
Abstract: The health of southern bluefin tuna (SBT), Thunnus maccoyii, in the Great Australian Bight was assessed. S les were obtained over 3 years (2010–2012) and over five in idual schools in 2012. Several blood variables and parasite loads were measured and used as indicators of SBT health. The health of wild SBT varied among years and among schools s led within the same month. Haemoglobin and the humoral immune parameters lysozyme and alternative complement activity explained the majority of the variation. Haemoglobin concentration, lysozyme activity, alternative complement activity, and lactate were lower in wild SBT s led in 2010 than in 2011 and 2012. The extent to which the health differences in wild SBT may affect ranched SBT is currently unknown. Benchmark values were set for various blood parameters and parasite loads in wild SBT.
Publisher: Brill
Date: 2006
Publisher: Wiley
Date: 07-2002
Publisher: Public Library of Science (PLoS)
Date: 09-08-2011
Publisher: Wiley
Date: 08-08-2008
Publisher: Elsevier BV
Date: 03-2000
Publisher: Wiley
Date: 08-2004
Publisher: Wiley
Date: 2009
DOI: 10.1111/J.1365-2761.2008.01010.X
Abstract: Within the typical 2-8 month (January to August inclusive) farming cycle for southern bluefin tuna, Thunnus maccoyii (Castelnau), in Spencer Gulf, South Australia, counts of a sea louse, Caligus chiastos Lin et Ho, 2003, were strongly statistically associated with both fish condition and severity of eye damage. During a trial examining the feasibility of maintaining T. maccoyii in farms for more than 1 year, including over the summer season when temperatures may exceed 24 degrees C, we collected additional epidemiological data on burdens of sea lice over a 17-month period (April 2005 to August 2006 inclusive), on a total of 200 T. maccoyii and 40 'control'T. maccoyii farmed and harvested within 2006. In the first farming season, an epizootic of C. chiastos was characterized by a significant increase in prevalence from 0% to 55% in the first 6 weeks after transfer to farms from the wild, which was followed by a significant decline to zero over the next 12 weeks. A single specimen of a second species of Caligus was also detected within this 4.5-month period. In the second farming season, we recorded a third species of sea louse, C. amblygenitalis Tripathi, 1961. In March 2006, a second epizootic peak occurred, this time with mixed infections of C. chiastos and C. amblygenitalis, with a combined prevalence of 100%. The prevalence of both sea lice species then declined significantly over the second winter period (June to August inclusive). On all but one date that sea lice were detected, sea lice counts were significantly associated with the severity of gross eye damage. Because both peaks in infection occurred in summer months (December to February inclusive), we conclude that infections of sea lice pose a risk to the farming of T. maccoyii under certain summer conditions within Spencer Gulf.
Publisher: Elsevier BV
Date: 03-2009
Publisher: Elsevier BV
Date: 11-2020
Publisher: Wiley
Date: 08-2004
Publisher: Elsevier
Date: 2016
Publisher: Elsevier BV
Date: 06-2012
DOI: 10.1016/J.FSI.2012.03.005
Abstract: Previously, we showed that IL-1β transcription is induced in the gills of amoebic gill disease (AGD)-affected fish in an AGD lesion-restricted fashion. However, in this environment, there is very little evidence of inflammation on histopathological or transcriptional levels and we hypothesised that aberrant signalling may occur. As a first step in investigating this issue, we cloned and sequenced the Atlantic salmon IL-1 receptor type II (IL-1RII) mRNA, and then examined the expression of both the IL-1RI (IL-1 receptor-like protein) and II during Neoparamoeba perurans infection. In gill lesions from AGD-affected fish, a step-wise temporal increase in the relative expression of IL-1β coincided with a significant reduction in IL-1RI, whereas the IL-1RII mRNA remained unchanged. Down-regulation of IL-1RI could explain the paucity of inflammation in affected tissue, although simultaneous up-regulation of IL-1β-inducible transcripts indicated that this is not due to a complete blockage of the IL-1RI pathway. Rather, it appears that IL-1RI transcription is reduced and this rate limits the effects of chronic IL-1β over-expression.
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.MOLBIOPARA.2013.07.002
Abstract: Three species of blood fluke from the genus Cardicola are known to parasitize and cause disease in Bluefin Tunas--C. forsteri, C. orientalis, and C. opisthorchis. Although initially believed to be separated by geography and host specificity, recent identification of at least two Cardicola spp. concurrently present within all three Bluefin species has raised questions concerning pathogenicity, relative abundance, and distribution of these parasites within Bluefin populations. Here, we present sensitive and differential real-time qPCR nucleic acid detection of these Cardicola spp. by targeting the ITS2 region of the parasite rDNA for PCR lification. A limit of sensitivity of 1-5 genome copy equivelents was achieved for each of the three Cardicola species tested without cross-species or host genomic lification. Similar sensitivity was further achieved in the presence of up to 20 ng/μL non-target host gDNA using SYBR Green chemistry alone, or in the presence of up to 160 ng/μL host gDNA through the utilization of a TaqMan probe common-reporter detection system. These methods were subsequently used to positively identify both C. forsteri and C. orientalis DNA in preserved s les of serum, gill, and heart from ranched Southern Bluefin Tuna Thunnus maccoyii. Both methods were more sensitive for positively and differentially identifying the presence of Cardicola spp. than either histological or heart-flush microscopy techniques previously employed, and also possess the ability to be applied in non-lethal blood s ling of these highly valued fish. This is the first report for rapid and differential molecular quantitative detection of Cardicola, and opens the potential for effective monitoring of infection in cultured bluefin populations. Further, it is anticipated that the use of SYBR Green for melt-curve analyses in conjunction with a common-reporter TaqMan assay will present a flexible, accurate, and cost-effective approach for differential detection of a variety of other pathogens in future.
Publisher: Oxford University Press
Date: 17-09-2020
DOI: 10.1093/OSO/9780190865627.003.0016
Abstract: This chapter provides a brief overview of crustacean parasites that infect commercially important fish and shellfish. Crustaceans are a erse group of arthropods, with over 60,000 species that are significant to the aquaculture and fisheries sector, including parasitic species affecting other crustaceans, mollusks, and fishes. This chapter focuses on parasitic caligid copepods (sea lice), cymothoid isopods, and pea crabs of high economic impacts on commercially important aquatic species. The biology of the parasites, their effects on their hosts, the epidemiology of the infections, and economic impacts of these groups are described. Chemical treatments and husbandry modifications as management options for a range of crustacean parasites are presented, which includes the use of cleaner fish to remove parasites, specially designed cages to reduce infestation of parasites, or moving farms to deeper waters. The utilization of crustacean parasites as marine pest controls is further discussed, with emphasis on either its potential benefits or the negative effects on native crab populations. Despite the continuous adverse impacts parasitic crustaceans have on aquaculture, the progressive understanding of their biology and ecology may eventually lead to mitigation, if not complete eradication, of the parasites.
Publisher: Elsevier BV
Date: 05-2020
Publisher: Wiley
Date: 16-07-2009
Publisher: MDPI AG
Date: 27-09-2021
DOI: 10.3390/PATHOGENS10101248
Abstract: The parasitic blood flukes Cardicola forsteri and C. orientalis are an ongoing health concern for Southern Bluefin Tuna Thunnus maccoyii (SBT) ranched in Australia. In this study we compared the effect of treatment, company, and ranching year on blood fluke infections in ranched SBT. SBT were s led during the 2018 and 2019 ranching seasons from praziquantel (PZQ) treated pontoons and untreated pontoons managed by two companies. Severity of infection was diagnosed by several criteria including adult fluke counts from hearts, egg counts from gill filaments and the use of specific quantitative polymerase chain reaction (qPCR) for detection of C. forsteri and C. orientalis ITS-2 DNA in SBT hearts and gills. PZQ treatment remains highly effective against C. forsteri infection. Prevalence and intensity of Cardicola spp. infection was lower in 2019 than 2018 for Company A in treated pontoons at week 12 and week 17 of ranching, and lower for Company A than Company B in untreated pontoons at month 5 of ranching. Results indicate re-infection may be less likely in the environment near Company A pontoons, and consistent years of treatment may have lowered the parasite load in the environment. qPCR demonstrated higher sensitivity when comparing diagnostic methods for C. forsteri in heart, and higher specificity when comparing diagnostic methods for Cardicola spp. in gills. Continuing to monitor blood fluke infections in ranched SBT can help to detect changes in drug efficacy over time and help industry to develop a best practice for treatment.
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.VETPAR.2008.02.027
Abstract: Tuna farming off Port Lincoln, Australia, involves catching wild 2-4-year-old southern bluefin tuna in summer and then fattening for periods of 2-8 months. As fresh product is not available year-round, the feasibility of maintaining tuna for longer periods was trialled, including over a summer season, when temperatures may exceed 24 degrees C. As the rates of growth and reproduction in ectoparasites of fishes are usually most rapid during warm temperatures, parasite epizootics at this time may adversely affect the health of tuna. We collected epidemiological data on burdens of metazoans on the gills of tuna from the time of stocking in April 2005 through to final harvest in August 2006 (N=220). We document an epizootic of the copepod Pseudocycnus appendiculatus, characterised by a significant increase in both prevalence and mean intensity in the first winter, followed by a decline in these parameters over the next 12 months. This epizootic pattern appears to be independent of seasonal changes in temperature. For two other species, a second copepod (Euryphorus brachypterus) and a polyopisthocotylean flatworm (Hexostoma thynni), there were no clearly discernible trends in infections. As the high water temperatures over the summer period did not lead to increased infections of any species of gill parasites, we conclude that they do not threaten the feasibility of farming of Thunnus maccoyii.
Publisher: Elsevier BV
Date: 05-2009
Publisher: Wiley
Date: 18-03-2008
DOI: 10.1111/J.1365-2761.2007.00863.X
Abstract: Three visible lesions were examined from two specimens of southern bluefin tuna. The lesions were examined grossly and two were identified as lipomas, the third bore similarities to a schwannoma. Histopathology confirmed that two consisted of mature adipocytes consistent with a diagnosis of lipoma. The third lesion consisted of spindle cells in Antoni A and B patterns and was tentatively diagnosed as a malignant schwannoma. Immunohistochemistry identified both S100 and glial fibrillary acid protein expression within the lesion, which, together with the histopathological appearance, is consistent with a diagnosis of neurofibrosarcoma.
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.VACCINE.2015.12.044
Abstract: Yersinia ruckeri is a ubiquitous pathogen of finfish capable of causing major mortalities in farmed fish stocks. It can be transmitted vertically from parent to progeny as well as horizontally in the water column from both clinically infected fish and asymptomatic carriers, and is consequently capable of infecting fish at early stages of development. Immunisation strategies that can protect small fry are therefore critical for the effective management of fish health, as is the ability to detect covertly infected fish. In this study, first-feeding Atlantic salmon fry (<0.5 g) were immunised either by oral administration of a microencapsulated Y. ruckeri vaccine formulation (0.38 g initial weight), or via immersion in bacterin suspension (0.26 g), with and without a booster immersion vaccination at 1g size. Protection in groups receiving only immersion immunisation did not differ significantly from untreated controls when challenged with Y. ruckeri at approximately 5 g size, while orally immunised fish were significantly better protected than untreated controls (F=4.38, df=4,10, P=0.026), with RPS varying between 29.4% (ORAL) and 51% (ORAL+DIP). A quantitative real-time PCR assay was used to successfully detect covertly infected fish among challenge survivors, indicating more than 50% of surviving fish in each group were infected with no significant differences between immunised fish and untreated controls.
Publisher: Wiley
Date: 27-11-2006
Publisher: Springer Science and Business Media LLC
Date: 25-01-2008
DOI: 10.1007/S10126-007-9075-4
Abstract: The transcriptome response of Atlantic salmon (Salmo salar) displaying advanced stages of amoebic gill disease (AGD) was investigated. Naïve smolt were challenged with AGD for 19 days, at which time all fish were euthanized and their severity of infection quantified through histopathological scoring. Gene expression profiles were compared between heavily infected and naïve in iduals using a 17 K Atlantic salmon cDNA microarray with real-time quantitative RT-PCR (qPCR) verification. Expression profiles were examined in the gill, anterior kidney, and liver. Twenty-seven transcripts were significantly differentially expressed within the gill 20 of these transcripts were down-regulated in the AGD-affected in iduals compared with naïve in iduals. In contrast, only nine transcripts were significantly differentially expressed within the anterior kidney and five within the liver. Again the majority of these transcripts were down-regulated within the diseased in iduals. A down-regulation of transcripts involved in apoptosis (procathepsin L, cathepsin H precursor, and cystatin B) was observed in AGD-affected Atlantic salmon. Four transcripts encoding genes with antioxidant properties also were down-regulated in AGD-affected gill tissue according to qPCR analysis. The most up-regulated transcript within the gill was an unknown expressed sequence tag (EST) whose expression was 218-fold (+/- SE 66) higher within the AGD affected gill tissue. Our results suggest that Atlantic salmon experiencing advanced stages of AGD demonstrate general down-regulation of gene expression, which is most pronounced within the gill. We propose that this general gene suppression is parasite-mediated, thus allowing the parasite to withstand or ameliorate the host response.
Publisher: Cold Spring Harbor Laboratory
Date: 20-05-2020
DOI: 10.1101/2020.05.19.105270
Abstract: Aquaculture is the fastest growing primary industry worldwide. Marine finfish culture in open ocean net pens, or pontoons, is one of the largest growth areas and is currently the only way to rear high value fish such as bluefin tuna. Ranching involves catching wild juveniles, stocking in floating net pens and fattening for four to eight months. Tuna experience several parasite-induced disease challenges in culture that can be mitigated by application of praziquantel (PZQ) as a therapeutic. In this study, we characterized the microbiome of ranched southern Bluefin Tuna, Thunnus maccoyii , across four anatomic sites (gill, skin, digesta, and anterior kidney) and evaluated environmental and pathological factors that influence microbiome composition, including the impact of PZQ treatment on microbiome stability. Southern bluefin tuna gill, skin, and digesta microbiome communities are unique and potentially influenced by husbandry practices, location of pontoon growout pens, and treatment with the antiparasitic PZQ. There was no significant relationship between the fish mucosal microbiome and incidence or abundance of adult blood fluke in the heart or fluke egg density in the gill. An enhanced understanding of microbiome ersity and function in high-value farmed fish species such as bluefin tuna is needed to optimize fish health and improve aquaculture yield. Comparison of the bluefin tuna microbiome to other fish species, including Seriola lalandi (yellowtail kingfish), a common farmed species from Australia, and Scomber japonicus (Pacific mackerel), a wild caught Scombrid relative of tuna, showed the two Scombrids had more similar microbial communities compared to other families. The finding that mucosal microbial communities are more similar in phylogenetically related fish species exposes an opportunity to develop mackerel as a model for tuna microbiome and parasite research.
Publisher: Elsevier BV
Date: 09-2015
Publisher: Magnolia Press
Date: 27-05-2015
DOI: 10.11646/ZOOTAXA.3963.3.1
Abstract: The genus Ceratothoa Dana, 1852, is revised for Australian waters. Ceratothoa is represented in Australia by nine species, including two new species: Ceratothoa barracuda sp. nov. described from Cairns and Ceratothoa globulus sp. nov. described from Lord Howe Island. Ceratothoa imbricata Fabricius, 1775 is redescribed, with Ceratothoa trillesi (Avdeev, 1979) and Ceratothoa huttoni Filhol, 1885 placed into junior synonymy the preferred hosts are species of the genus Trachurus (Carangidae). Ceratothoa banksii (Leach, 1818) is validated and brought out of synonymy with Ceratothoa imbricata host species are from the families Kyphosidae, Scombridae, Latridae, Carangidae, Mugilidae, Salmonidae, Scatophagidae, Pomatomidae and Hemir hidae. Species excluded from the Australian fauna are Ceratothoa trigonocephala (Leach, 1818) with an unknown host identity and type locality and Ceratothoa lineata Miers, 1876a, that here is transferred to the genus Mothocya Costa, 1851, with Mothocya ihi Bruce, 1986 placed into junior synonymy. Ceratothoa contracta (Miers, 1880), the New Zealand Ceratothoa novaezelandiae Filhol, 1885 and the East Pacific Ceratothoa gaudichaudii (Milne Edwards, 1840) are regarded here as species inquirenda. A key to the Australian species of Ceratothoa is presented.
Publisher: Elsevier BV
Date: 06-2003
DOI: 10.1016/S0145-305X(03)00034-X
Abstract: Pentraxin-like molecules have been isolated from a number of fish species. However, little is known about the function of these proteins in the teleosts. In this study we report the isolation and characterization of a pentraxin-like molecule from the serum of snapper (Pagrus auratus) that has the ability to activate complement. This pentraxin-like protein was isolated from serum by calcium-dependent binding to agarose. SDS-PAGE analysis demonstrated an oligomeric protein of approximately 200k Da consisting of non-covalently bound subunits of 26 and 23 kDa. Protein sequencing revealed significant (50%) sequence identity with pentraxins from both Atlantic salmon (S. salar) and rainbow trout (O. mykiss). However, polyclonal antibodies raised against snapper pentraxin did not recognise salmon or trout pentraxin in Western blot analysis. Following LPS injection, snapper pentraxin levels increased 2-fold before gradually returning to basal levels. Most significantly, the isolated pentraxin initiated complement-mediated lysis of ligand-coated sheep erythrocytes in a dose-dependent fashion. In view of the similarity between the known fish pentraxins, and their similarity to mammalian serum amyloid P-components we conclude that the isolated protein may be a snapper pentraxin homologue.
Publisher: Elsevier BV
Date: 10-2016
Publisher: Elsevier BV
Date: 07-2011
DOI: 10.1016/J.IJPARA.2011.03.011
Abstract: Aporocotylids (fish blood flukes) are emerging as pathogens of fishes in both marine and freshwater aquaculture. Efforts to control these parasites are h ered by a lack of life cycle information. Here we report on the life cycle of Cardicola forsteri, which is considered a significant pathogen in southern bluefin tuna, Thunnus maccoyi, ranched in South Australia. We surveyed polychaetes, bivalves and gastropods from sites close to tuna pontoons. Infections consistent with the Aporocotylidae were found in terebellid polychaetes, a single Longicarpus modestus and five in iduals of Reterebella aloba. All infections were comprised of hundreds of sporocysts in the body cavity of the host, each filled with developing and mature cercariae. Sequences of ITS-2 and lsrDNA from the infection from L. modestus were a perfect match with those of adult C. forsteri from T. maccoyi. This life cycle link is considered confirmed but it is possible that additional terebellid species are infected in South Australia equally, other species of intermediate host are likely to be involved in other parts of the range of this cosmopolitan trematode. Sequences of the species from R. aloba did not match a known adult but phylogenetic analysis of lsrDNA suggests that it is also a species of Cardicola Short, 1953. These findings show that terebellid polychaetes are a major host group for marine aporocotylids, especially given that Cardicola is the largest marine aporocotylid genus. The two cercarial types are among the smallest known for the family and are unusual, but not unique, in having short, simple tails. We speculate that the form of the tail means that these cercariae are not active swimmers and are thus heavily dependent on currents for dispersal. Control of this parasite might be effected by moving the tuna pontoons appropriate distances to avoid encounter with current-dispersed cercariae, or by increasing the separation of the nets from the sea floor, either by raising the nets or moving to deeper water.
Publisher: Springer Science and Business Media LLC
Date: 28-03-2017
DOI: 10.1007/S10646-017-1793-4
Abstract: Arsenic (As) and mercury (Hg) are ubiquitous elements known to disrupt thyroid function in vertebrates. To explore the underlying mechanisms of Hg and As on the fish thyroid system, we investigated the associations between muscle concentrations of Hg and As with thyroid-related gene transcription in flathead (Platycephalus bassensis) from a contaminated estuary. We s led fish at several sites to determine the hepatic expression of genes including deiodinases (D1 and D2), transthyretin (TTR), thyroid hormone receptors (TRα and TRβ) and related them to Hg and As levels in the same in iduals. Negative correlations were observed between Hg levels and D2, TTR, TRα and TRβ, whereas positive associations were found between As concentrations and TTR and TRβ. These results suggest that Hg and As exposures from environmental pollution affect the regulation of genes important for normal thyroid function in fish. These thyroid-related genes could be used as biomarkers for monitoring environmental thyroid-hormone disrupting chemicals.
Publisher: Elsevier BV
Date: 11-2007
DOI: 10.1016/J.FSI.2007.04.003
Abstract: Tumour necrosis factor-alpha (TNF-alpha) is a key mediator of inflammation during amoebiasis of humans and mice. Atlantic salmon (Salmo salar L.) are also susceptible to infection by amoebae (Neoparamoeba spp.), inflicting a condition known as amoebic gill disease (AGD). Here, the role of TNF-alpha in AGD-pathogenesis was examined. Two Atlantic salmon TNF-alpha transcripts designated TNF-alpha1 and TNF-alpha2 together with their respective genes were cloned and sequenced. TNF-alpha1 is 1379 bp and consists of a 738 bp open reading frame (ORF) translating into a predicted protein of 246 amino acids. TNF-alpha2 is 1412 bp containing an ORF and translated protein the same lengths as TNF-alpha1. An anti-rainbow trout TNF-alpha polyclonal antibody that bound recombinant Atlantic salmon TNF-alpha1 and TNF-alpha2 was used to detect constitutive and inducible expression of TNF-alpha in various tissues. The anti-TNF-alpha antibody bound to a TNF-like protein approximately 60 kDa that was constitutively expressed in a number of tissues in healthy Atlantic salmon. However, this protein was not detected in lysates from mitogen-stimulated head kidney leucocytes, despite up-regulation of TNF-alpha mRNAs under the same conditions. During the early onset of AGD in Atlantic salmon, there were no demonstrable differences in the gill tissue expression of TNF-alpha1, TNF-alpha2 nor the interleukin-1 beta (IL-1beta), inducible nitric oxide synthase (iNOS) and interferon gamma (IFN-gamma) mRNAs compared to tissue from healthy fish. In Atlantic salmon with advanced AGD, IL-1beta but not TNF-alpha1 or TNF-alpha2 mRNAs was up-regulated and was lesion-restricted. Given that Neoparamoeba spp. modulated both TNF-alpha2 and IL-1beta in head kidney leucocytes in vitro, it appears that rather than being recalcitrant to Neoparamoeba spp.-mediated TNF-alpha expression, either the parasite can influence the cytokine response during infection, there is ineffective signalling for TNF-alpha expression, or there are too few cells at the site of infection with the capacity to produce TNF-alpha. These data support our previous observation that IL-1beta mRNA expression is up-regulated in AGD-affected tissue and that TNF-alpha is not intrinsic in AGD-pathogenesis.
Publisher: Inter-Research Science Center
Date: 16-06-2011
DOI: 10.3354/DAO02329
Abstract: The fish disease marine flexibacteriosis is characterised by necrotic lesions on the body, head, fins, and occasionally gills, with erosive lesions on the external surface as the prominent clinical sign. In Australia, the main species affected are Atlantic salmon Salmo salar and rainbow trout Oncorhynchus mykiss in sea-cage culture in Tasmania. Using a dose-dependent trial to determine pathology, 2 forms of the disease were noted in Atlantic salmon. The acute form occurs within 2 to 3 d after inoculation at high doses (1 x 10(8) cells ml(-1)) and is characterised by the disintegration of the epithelium. The chronic form of the disease began as small superficial blisters of the epidermis, which develop into ulcerative lesions that leave musculature exposed. The predominant lesion sites were the dorsum and pectoral fins. Jaws were commonly affected, and gill necrosis was also noted. Behaviour of Atlantic salmon as well as the conditions under which they were kept contribute to the size and distribution of lesions observed. Lack of an inflammatory response in pathology and rapid and destructive mortalities observed in higher inoculum doses suggested a role of toxins in the pathogenesis of Tenacibaculum maritimum. This is the first study to examine the development of marine flexibacteriosis lesions and to utilise immunohistochemistry to verify that the bacteria observed in histology was T. maritimum.
Publisher: Wiley
Date: 10-2002
Publisher: Inter-Research Science Center
Date: 09-08-2017
DOI: 10.3354/AEI00233
Publisher: Springer Science and Business Media LLC
Date: 07-09-2019
Publisher: Elsevier BV
Date: 06-2023
Publisher: Springer Science and Business Media LLC
Date: 21-04-2011
Publisher: Elsevier BV
Date: 08-2001
Publisher: Elsevier BV
Date: 11-2001
Abstract: This study investigated the in vitro effects of a commercial beta-glucan preparation, EcoActiva, on the respiratory burst activity of head-kidney macrophages isolated from pink snapper (Pagrus auratus), a marine fish cultured in Australia. Macrophages incubated with EcoActiva displayed morphological characteristics of activation, and were stimulated to produce superoxide. Pre-incubation with low levels of EcoActiva significantly increased the response to phorbol myristate acetate (PMA) and lipopolysaccharide (LPS), indicating that EcoActiva could prime these macrophages. Co-culturing macrophages with both LPS and PMA, or EcoActiva and PMA, increased burst activity compared with the response to PMA alone, however, this increase was additive and not synergistic. These results suggest that EcoActiva is able to stimulate non-specific immunity in snapper through increased respiratory burst activity of macrophages, an important component of the host defence network.
Publisher: Wiley
Date: 04-2002
Publisher: Wiley
Date: 06-02-2013
DOI: 10.1111/JFD.12078
Abstract: Formaldehyde-based fixatives are generally employed in histopathology despite some significant disadvantages associated with their usage. Formaldehyde fixes tissue by covalently cross-linking proteins, a process known to mask epitopes which in turn can reduce the intensity of immunohistochemical stains widely used in disease diagnostics. Additionally, formaldehyde fixation greatly limits the ability to recover DNA and mRNA from fixed specimens to the detriment of further downstream molecular analyses. Amoebic gill disease (AGD) has been reliably diagnosed from histological examination of gills although complementary methods such as in situ hybridization (ISH) and polymerase chain reaction (PCR) are required to confirm the presence of Neoparamoeba perurans, the causative agent of AGD. As molecular techniques are becoming more prevalent for pathogen identification, there is a need to adapt specimen collection and preservation so that both histology and molecular biology can be used to diagnose the same s le. This study used a general approach to evaluate five different fixatives for Atlantic salmon, Salmo salar L., gills. Neutral-buffered formalin and seawater Davidson's, formaldehyde-based fixatives commonly used in fish histopathology, were compared to formalin-free commercial fixatives PAXgene®, HistoChoice™MB* and RNAlater™. Each fixative was assessed by a suite of analyses used to demonstrate AGD including routine histochemical stains, immunohistochemical stains, ISH and DNA extraction followed by PCR. All five fixatives were suitable for histological examination of Atlantic salmon gills, with seawater Davidson's providing the best quality histopathology results. Of the fixatives evaluated seawater Davidson's and PAXgene® were shown to be the most compatible with molecular biology techniques. They both provided good DNA recovery, quantity and integrity, from fixed and embedded specimens. The capacity to preserve tissue and cellular morphology in addition to allowing molecular analyses of the same specimens makes seawater Davidson's and PAXgene® appear to be the best fixation methods for diagnosis and research on AGD in Atlantic salmon gills.
Publisher: Elsevier BV
Date: 03-2022
DOI: 10.1016/J.FSI.2022.02.035
Abstract: Amoebic gill disease, caused by the protozoan ectoparasite Neoparamoeba perurans, remains a significant threat to commercial Atlantic salmon aquaculture operations worldwide, despite partial control afforded by selective breeding and therapeutic intervention. Anecdotal reports from commercial producers suggest that historically, smaller Atlantic salmon smolts are more susceptible to AGD than larger smolts. Here, large (>350 g) and small (<200 g) commercially sourced, AGD-naïve Atlantic salmon cohorts were experimentally exposed to 50 N. perurans trophozoites L
Publisher: Elsevier BV
Date: 06-2003
DOI: 10.1016/S0145-305X(03)00034-X
Abstract: Pentraxin-like molecules have been isolated from a number of fish species. However, little is known about the function of these proteins in the teleosts. In this study we report the isolation and characterization of a pentraxin-like molecule from the serum of snapper (Pagrus auratus) that has the ability to activate complement. This pentraxin-like protein was isolated from serum by calcium-dependent binding to agarose. SDS-PAGE analysis demonstrated an oligomeric protein of approximately 200k Da consisting of non-covalently bound subunits of 26 and 23 kDa. Protein sequencing revealed significant (50%) sequence identity with pentraxins from both Atlantic salmon (S. salar) and rainbow trout (O. mykiss). However, polyclonal antibodies raised against snapper pentraxin did not recognise salmon or trout pentraxin in Western blot analysis. Following LPS injection, snapper pentraxin levels increased 2-fold before gradually returning to basal levels. Most significantly, the isolated pentraxin initiated complement-mediated lysis of ligand-coated sheep erythrocytes in a dose-dependent fashion. In view of the similarity between the known fish pentraxins, and their similarity to mammalian serum amyloid P-components we conclude that the isolated protein may be a snapper pentraxin homologue.
Publisher: MDPI AG
Date: 31-03-2020
DOI: 10.3390/IJMS21072417
Abstract: Parasitic sea lice (e.g., Lepeophtheirus salmonis) cause costly outbreaks in salmon farming. Molecular insights into parasite-induced host responses will provide the basis for improved management strategies. We investigated the early transcriptomic responses in pelvic fins of Atlantic salmon parasitized with chalimus I stage sea lice. Fin s les collected from non-infected (i.e., pre-infected) control (PRE) and at chalimus-attachment sites (ATT) and adjacent to chalimus-attachment sites (ADJ) from infected fish were used in profiling global gene expression using 44K microarrays. We identified 6568 differentially expressed probes (DEPs, FDR 5%) that included 1928 shared DEPs between ATT and ADJ compared to PRE. The ATT versus ADJ comparison revealed 90 DEPs, all of which were upregulated in ATT s les. Gene ontology athway term network analyses revealed profound changes in physiological processes, including extracellular matrix (ECM) degradation, tissue repair/remodeling and wound healing, immunity and defense, chemotaxis and signaling, antiviral response, and redox homeostasis in infected fins. The QPCR analysis of 37 microarray-identified transcripts representing these functional themes served to confirm the microarray results with a significant positive correlation (p 0.0001). Most immune/defense-relevant transcripts were downregulated in both ATT and ADJ sites compared to PRE, suggesting that chalimus exerts immunosuppressive effects in the salmon’s fins. The comparison between ATT and ADJ sites demonstrated the upregulation of a suite of immune-relevant transcripts, evidencing the salmon’s attempt to mount an anti-lice response. We hypothesize that an imbalance between immunomodulation caused by chalimus during the early phase of infection and weak defense response manifested by Atlantic salmon makes it a susceptible host for L. salmonis.
Publisher: Elsevier BV
Date: 05-2009
DOI: 10.1016/J.FSI.2009.03.012
Abstract: This study reports the cloning and sequencing of three striped trumpeter (Latris lineata Forster) pro-inflammatory cytokines, TNF-alpha, IL-1beta and IL-8, as well as their differential expression in response to an infection by the ectoparasite Chondracanthus goldsmidi. The striped trumpeter TNF-alpha transcript consisted of 1093 bp, including a 759 bp ORF which translated into a 253 aa transmembrane peptide. The sequence contained a TACE cut site, that would produce a 167 aa soluble peptide containing the TNF ligand family signature. The IL-1beta sequence consisted of 963 bp, including a 774 bp ORF which translated into a 258 aa protein. The protein lacked both a signal peptide and an ICE cleavage site, but did contain the IL-1 family signature. The sequence for the chemokine IL-8 contained 906 bp, with an ORF of 297 bp, which translated into a 99 aa protein. The protein lacked an ELR motif as is common with many teleost IL-8 sequences. The differential expression of the three cytokine genes in parasitized fish was investigated via quantitative real-time PCR. A significant up-regulation of all three pro-inflammatory cytokines was found in the gills, which were the site of parasite attachment. Examination of head kidney cells revealed a significant up-regulation of TNF-alpha, but not IL-1beta or IL-8. Conversely, the spleen cells showed significant up-regulation of both IL-1beta and IL-8, but not TNF-alpha. These findings allow for more detailed investigations of the striped trumpeter immune response.
Publisher: Hindawi Limited
Date: 12-2001
Publisher: Wiley
Date: 07-08-2012
DOI: 10.1111/J.1365-2761.2012.01422.X
Abstract: Currently, the only effective and commercially used treatment for amoebic gill disease (AGD) in farmed Tasmanian Atlantic salmon is freshwater bathing. Hydrogen peroxide (H₂O₂), commonly used throughout the aquaculture industry for a range of topical skin and gill infections, was trialled in vitro and in vivo to ascertain its potential as an alternative treatment against AGD. Under in vitro conditions, trophozoites of Neoparamoeba perurans were exposed to three concentrations of H₂O₂ in sea water (500, 1000 and 1500 mg L⁻¹) over four durations (10, 20, 30 and 60 min) each at two temperatures (12 and 18 °C). Trophozoite viability was assessed immediately post-exposure and after 24 h. A concentration/duration combination of 1000 mg L⁻¹ for >10 min demonstrated potent amoebicidal activity. Subsequently, Atlantic salmon mildly affected with experimentally induced AGD were treated with H₂O₂ at 12 and 18 °C for 15 min at 1250 mg L⁻¹ and their re-infection rate was compared to freshwater-treated fish over 21 days. Significant differences in the percentage of filaments affected with hyperplastic lesions (in association with amoebae) and plasma osmolality were noted between treatment groups immediately post-bath. However, the results were largely equivocal in terms of disease resolution over a 3-week period following treatment. These data suggest that H₂O₂ treatment in sea water successfully ameliorated a clinically light case of AGD under laboratory conditions.
Publisher: Elsevier BV
Date: 03-2012
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/MF99010
Abstract: The 100-year operation of the Mount Lyell Mining and Railway Company Limited’s copper mine in Queenstown, Australia, has resulted in the deposition of over 100 million cubic metres of mine tailings, smelter slag and topsoil into the King River and Macquarie Harbour. Apreliminary risk assessment, together with chemical measurements of dissolved copper, ASV-labile copper, copper complexing capacity and resin-adsorbed copper, suggested that copper in mid-salinity harbour waters was potentially bioavailable. However, toxicity tests based on inhibition of microalgal (Nitzschia closterium) growth showed that copper in these waters was not toxic, even though labile copper concentrations (6–24 µg L−1) exceeded the concentration of lowest observable effect for algae of 5 mg L−1. Measurements of intracellular and membrane-bound copper confirmed that cell ision was not affected because copper was not taken up intracellularly. Amelioration of copper toxicity was due to binding of dissolved organic matter and/or other metals at the cell membrane, preventing copper binding and uptake. An understanding of the mechanism of copper toxicity and its amelioration is vital to assessing various clean-up options for the harbour.
Publisher: Elsevier BV
Date: 12-2016
DOI: 10.1016/J.FSI.2016.11.014
Abstract: Melanomacrophage centres (MMCs) are common in the haemopoietic tissue of fish and are an important component of the humoral immune response. Increasingly they are being studied as a biomarker of environmental stress in both wild and aquaculture fish stocks. Computer image analysis of histological sections of the head kidney and spleen of ranched Southern bluefin tuna (SBT) was used to investigate changes in MMCs over various stages of the ranching cycle. Histochemical pigment differentiation indicated haemosiderin, lipofuscin and melanin were present in MMCs of both the kidney and spleen, with kidney MMCs being highly positive for lipofuscin and melanin and spleen having high levels of haemosiderin and a lower level of melanin than kidney. The MMC area in the kidney of wild s led SBT ranged from 0.41 ± 0.13% to 2.95 ± 0.26% and that in the spleen ranged from 0.35 ± 0.09% to 2.75 ± 0.86%. The MMC area in the spleen of SBT increased over the latter stages of ranching and at harvest compared to SBT s led in the wild and at the end of tow. There was no statistically significant difference in the MMC area in the kidney of ranched SBT s led at various stages. SBT appear to have a higher MMC area in haemopoietic organs than numerous other fish species, perhaps providing a greater capacity to deal with 'wear and tear' and increased immune-competence.
Publisher: Informa UK Limited
Date: 09-08-2018
Publisher: Elsevier BV
Date: 05-2001
Publisher: Wiley
Date: 05-2010
Publisher: Elsevier BV
Date: 10-2021
Publisher: Inter-Research Science Center
Date: 02-09-2010
DOI: 10.3354/DAO02219
Abstract: Tenacibaculum maritimum causes marine flexibacteriosis in many cultured fish species, including Atlantic salmon Salmo salar in Tasmania, Australia. Several aspects of the pathogenicity of this bacterium were investigated in naive Atlantic salmon smolts using different isolates, growth conditions and doses to produce a model of infection. We found that T. maritimum is pathogenic to Atlantic salmon using either marine Shieh's or marine Ordal's culture medium. The use of aeration in broth culture produced a dose effect in challenge due to a 'clumping' of the bacteria during culture. The virulence of a strain appears to be connected with this 'clumping' the more adherent the cells, the more pathogenic the strain. Differences in virulence between 3 strains was apparent, with 1 of the strains (89/4747) being non-pathogenic and unable to produce disease in the host. The 2 other strains (89/4762, 00/3280) were highly virulent, resulting in 100% mortalities within 3 d. A reproducible model of infection has been established in the present study using strain 89/4762. Results from the present study provide a better insight into the nature of the disease.
Publisher: Inter-Research Science Center
Date: 2003
DOI: 10.3354/DAO056135
Abstract: We investigated the effect of time after pulse exposure to 1.0 microg l(-1) endosulfan (applied as Thiodan) on endosulfan residues in the liver and ultrastructural changes in the hepatocytes of the freshwater catfish Tandanus tandanus. Time after exposure did not affect the mean residue level in the liver. After exposure to endosulfan, residues in the liver were 227.47 microg kg(-1) after 1 d and 282.83 microg kg(-1) after 28 d residues in the bile were 313.97 microg kg(-1) after 1 d and 334.53 microg kg(-1) after 28 d. At the end of 28 d exposure, lipofuscin was present in up to 69% of hepatocytes of fish containing residues of endosulfan, but absent from control fish. There was a statistically significant increase in the percentage of pyknotic nuclei and altered rough endoplasmic reticulum 28 d after exposure. The mean percentage of cells with altered endoplasmic reticulum ranged from 12.93% (Day 1) to 7.50% (Day 28) for control fish, while for exposed fish it increased from 14.30% (Day 1) to 35.00% (Day 28). The mean percentage of cells with pyknotic nuclei increased from 1.1 to 2.1% in control fish and from 3.8 to 9.6% in exposed fish. Other ultrastructural changes included increased ultrastructural heterogeneity, progressive vacuolation and fractionation of rough endoplasmic reticulum, accumulation of lysosomes and residual bodies, intranuclear inclusions and pseudoinclusions, membrane whorls and myelinated bodies. Protracted senescence was one of the main features of endosulfan toxicity to T. tandanus hepatocytes.
Publisher: Elsevier BV
Date: 05-2014
DOI: 10.1016/J.FSI.2014.02.023
Abstract: Praziquantel (PZQ), long-used in veterinary and human medicine for the treatment of helminth parasites, is known to enhance humoral and cellular immune responsiveness in mammals but has unknown direct immunomodulatory capabilities in fish. In the present study, we examined the ability of PZQ to induce gene transcriptional changes in immune-competent primary tissue/organ cultures of two highly important yet evolutionarily discrete fish species--Southern bluefin tuna Thunnus maccoyii and Atlantic salmon Salmo salar. These cultures consisted of mixed blood cell population for both species, as well as intestinal explants from bluefin. Although expression profiles varied between species and tissue/organ type, PZQ induced both T-cell receptor (more than twofold) and IL-8 transcriptional expression (more than fourfold). Additionally, increased expression of other inflammatory cytokines including IL-1β was detected in blood cell cultures from both species, and a general pattern of heightened antiviral signaling was observed. Specifically, elevated transcription of Type I (IFNα) and Type II (IFNγ) interferon in Atlantic salmon blood cultures along with elevated expression of MHC class I in blood cultures of both species. These findings provide preliminary evidence for direct immunomodulation by PZQ in fish and insight into its potential capacity as an immune stimulant/adjuvant in the rapidly expanding aquaculture industry.
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.ENVRES.2018.04.016
Abstract: The former lead-zinc mine at Mestersvig, Greenland, continues to contaminate the surrounding environment despite its operations ceasing over 50 years ago. Elevated concentrations of heavy metals are found in water, sediment and biota in the terrestrial, freshwater and marine environments. To shed light on the present contamination and its potential effects on local fish we investigated gill and liver histology of sculpins (Myoxocephalus spp.) around the former mining area. Two species of sculpins were caught shorthorn sculpins (M. scorpius n = 16) and fourhorn sculpins (M. quadricornis n = 17) at a contaminated site, Nyhavn, and shorthorn sculpins (M. scorpius n = 25) at the reference site. In a previous study we found histopathological changes in the tissues of the sculpins, and we suspected this to be related to elevated heavy metal tissue concentrations. Concentrations of Fe, Hg, Mn, Pb, Se and Zn were significantly higher in sculpins at Nyhavn compared to the reference site. Reference NOED and LOEC thresholds for biochemistry, tissue lesions, growth, survival and reproduction for hepatic Hg, As, Cd and Pb from the ERED database were exceeded in both sculpin species. Histopathological investigations of the sculpins gills revealed significant increases in the prevalence of hyperplastic epithelium, inflammation, intensity of neutral and total mucus cells and chloride cells along with an increased infection of colonial Peritricha. At the contaminated Nyhavn site, fourhorn sculpins had a significantly higher prevalence of chondroplastic tissue and intensity of neutral, mixed and total mucus cells in the gills compared to the shorthorn sculpins. The data indicate that both sculpin species could be useful indicator species for environmental monitoring of metal pollution in Arctic areas. However, confounding effects of gender and species should be investigated further. Effects on other biomarkers as well as baseline measurements should be included in future environmental monitoring efforts around mining activities in Greenland.
Publisher: Elsevier BV
Date: 2016
Publisher: Elsevier BV
Date: 05-2003
Publisher: MDPI AG
Date: 18-01-2021
DOI: 10.3390/PATHOGENS10010079
Abstract: Melanomacrophage centres (MMCs) are aggregates of macrophages accumulating various pigments. They have been proposed as an indicator of fish immune response. Blood flukes are common parasites in farmed fish. Two cohorts of wild Southern Bluefin Tuna (Thunnus maccoyi) were examined at transfer, before treatment against blood flukes (pre-treatment) and at harvest. MMCs were assessed in histological sections using image analysis, while Cardicola forsteri and Cardicola orientalis infection severity was determined using qPCR, count of adult flukes in heart flushes and count of eggs in gill filaments. Fish from both cohorts showed the same pattern in the changes in the surface area of MMCs. The surface area of splenic MMCs increased over the ranching duration and was positively correlated to the PCR determined copy numbers of Cardicola forsteri ITS2 rDNA in the gills of those fish. However, the infection with blood fluke was more variable, both between cohorts and in iduals within the same cohort. Eggs of blood fluke were detected in renal MMCs using histology. Cardicola forsteri had a higher prevalence than Cardicola orientalis. This study contributes to our understanding of blood fluke infections in Southern Bluefin Tuna and their interactions with MMCs.
Publisher: Elsevier BV
Date: 05-2012
DOI: 10.1016/J.IJPARA.2012.04.002
Abstract: Amoebic gill disease (AGD) in marine farmed Atlantic salmon is of growing concern worldwide and remains a significant health issue for salmon growers in Australia. Until now the aetiological agent, Neoparamoeba perurans, has not been amenable to in vitro culture and therefore Koch's postulates could not be fulfilled. The inability to culture the amoeba has been a limiting factor in the progression of research into AGD and required the maintenance of an on-going laboratory-based infection to supply infective material. Culture methods using malt yeast agar with sea water overlaid and subculturing every 3-4 days have resulted in the establishment of a clonal culture of N. perurans, designated clone 4. Identity of the amoeba was confirmed by PCR. After 70 days in culture clone 4 infected Atlantic salmon, causing AGD, and was re-isolated from the infected fish. Diagnosis was confirmed by histology and the infectious agent identified by PCR and in situ hybridisation using oligonucleotide primers and probes previously developed and specific to N. perurans. This study has fulfilled Koch's postulates for N. perurans as a causative agent of AGD and illustrates its free-living and parasitic nature.
Publisher: Springer Science and Business Media LLC
Date: 28-08-2021
Publisher: Elsevier BV
Date: 03-2006
DOI: 10.1016/J.FSI.2005.05.014
Abstract: Amoebic gill disease (AGD) is an ectoparasitic disease caused by infection with the protozoan Neoparamoeba sp. and is characterised by epithelial hyperplasia that manifests as gill lesions. In order to examine the nature of the immune response to AGD, the expression of a range of immune-regulatory genes was examined in naïve uninfected rainbow trout, Oncorhynchus mykiss, and naïve rainbow trout subjected to a laboratory-induced AGD infection. The immune-regulatory genes examined were interleukin-1 beta isoform 1 (IL-1beta1), tumour necrosis factor alpha isoforms 1 and 2 (TNF-alpha1, TNF-alpha2), interleukin-8 (IL-8), transforming growth factor beta isoform 1 (TGF-beta1), inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), major histocompatibility complex beta chain (MHC-II beta-chain) and T-cell receptor beta chain (TCR beta-chain). Immune-regulatory genes that were up/down-regulated in AGD-infected trout compared to uninfected controls at 0, 7, and 14 days post-inoculation (p.i.) in gill, liver and anterior kidney tissue were initially identified by means of semi-quantitative RT-PCR. Up/down-regulated immune-regulatory genes were subsequently quantitated and validated by real-time RT-PCR (qRT-PCR). The extent of AGD-associated pathology was consistent amongst all AGD-infected trout at 7 days p.i. and increased considerably by 14 days p.i. At both 7 and 14 days p.i. IL-1beta1 and iNOS gene expression was significantly up-regulated in the gills, and IL-8 was significantly up-regulated in the liver of AGD-infected trout at 7 days p.i. These data demonstrate the involvement of the immune response to AGD at the molecular level, and indicate the importance of this response at the site of infection and the possible involvement of a systemic immune response.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 02-2012
DOI: 10.1016/J.CHEMOSPHERE.2011.10.044
Abstract: Composite s les of Australian farmed Yellowtail Kingfish (Seriola lalandi) (YTKF) (n=27), Mulloway (Argyrosomus hololepidotus) (n=6) and manufactured feed (n=5) were analysed to benchmark levels of a broad range of residues and contaminants of potential public health and trade significance. A subset of these s les [YTKF (n=5), Mulloway (n=2) and feed (n=5)] was analysed for dioxins and polychlorinated biphenyls (PCBs). The mean concentration of dioxins in YTKF was 0.6 pg TEQ g(-1) (range 0.22-0.8) and in Mulloway was 0.16 pg TEQ g(-1) (range 0.16-0.16). The mean concentration of dioxins and dioxin-like PCBs in YTKF was 2.6 pg TEQ g(-1) (range 1.4-3.5), while Mulloway had a mean concentration of 0.67 pg TEQ g(-1) (range 0.57-0.76). The mean concentration of PCBs in YTKF was 21 μg kg(-1) (range 8.6-29) and in Mulloway was 5.4 μg kg(-1) (mean 4.7-6). The mean concentration of dioxin-like PCBs in YTKF was 2.1 pg TEQ g(-1) (range 1.2-2.8) and in Mulloway was 0.51 pg TEQ g(-1) (range 0.41-0.61). The mean mercury concentration in YTKF was 0.03 mg kg(-1) (range 0.02-0.05) and in Mulloway it was 0.02 mg kg(-1) (range 0.02-0.04). There were no detectable levels of any pesticide or antimicrobial compounds in any s le of YTKF or Mulloway. Attention is drawn to technical differences in port of entry testing programs such as s ling strategies, portion tested, laboratory methodology, residue definitions and reporting conventions that exporters' products may be subject to. All residues and contaminants were either undetectable or present at very low levels when judged against Australian, Japanese and European Union regulatory standards (where set).
Publisher: Elsevier BV
Date: 02-2014
Publisher: Oxford University Press (OUP)
Date: 19-07-2013
DOI: 10.1111/JAM.12286
Abstract: The Australian tuna industry is based on the ranching of wild southern bluefin tuna (SBT, Thunnus maccoyii). Within this industry, only opportunistic pathogens have been reported infecting external wounds of fish. This study aimed to identify different culturable bacteria present in three cohorts of SBT and to determine normal bacteria and potential pathogens in isolates from harvest fish and moribund/dead fish. Post-mortem changes in the microbiota were also studied. Moribund/dead showed a greater proportion of members from the family Vibrionaceae than harvested fish the latter presented mainly non-Vibrio species. In harvested fish spleens, Vibrio splendidus I complex was the most commonly identified group among Vibrio isolates, while most groups from the family Vibrionaceae were isolated from gills. For moribund/dead, Vibrio chagasii and Photobacterium damselae subsp. damselae were common in gill, spleen and kidney s les. Non-Vibrio isolates from gills were characterized using 16S rRNA sequencing as Flavobacteriaceae and classes Gammaproteobacteria and Alphaproteobacteria, mainly from the genera Winogradskyella and Tenacibaculum. Post-mortem changes showed dynamic shifts in bacterial dominance in gills, with Vibrionaceae and non-Vibrio spp. found in similar proportions initially and types related to Pseudoalteromonas ruthenica prevailing after 27 h. Spleen s les showed little bacterial growth until 5 h post-mortem, while various Vibrio-associated species were isolated 27 h post-mortem. Bacterial isolates found include a range of potentially pathogenic bacteria that should be monitored though most of them have yet to be associated with disease in tuna. This study forms a foundation for future research into the bacterial population dynamics under different culture conditions of SBT. An understanding of the bacterial compositions in SBT is necessary to evaluate the effects of some bacterial species on their health.
Publisher: American Society for Microbiology
Date: 2006
DOI: 10.1128/AEM.72.1.284-290.2006
Abstract: Epitheliocystis in leafy seadragon ( Phycodurus eques ), silver perch ( Bidyanus bidyanus ), and barramundi ( Lates calcarifer ), previously associated with chlamydial bacterial infection using ultrastructural analysis, was further investigated by using molecular and immunocytochemical methods. Morphologically, all three species showed epitheliocystis cysts in the gills, and barramundi also showed lymphocystis cysts in the skin. From gill cysts of all three species and from skin cysts of barramundi 16S rRNA gene fragments were lified by PCR and sequenced, which clustered by phylogenetic analysis together with other chlamydia-like organisms in the order Chlamydiales in a lineage separate from the family Chlamydiaceae . By using in situ RNA hybridization, 16S rRNA Chlamydiales -specific sequences were detected in gill cysts of silver perch and in gill and skin cysts of barramundi. By applying immunocytochemistry, chlamydial antigens (lipopolysaccharide and/or membrane protein) were detected in gill cysts of leafy seadragon and in gill and skin cysts of barramundi, but not in gill cysts of silver perch. In conclusion, this is the first time epitheliocystis agents of leafy seadragon, silver perch and barramundi have been undoubtedly identified as belonging to bacteria of the order Chlamydiales by molecular methods. In addition, the results suggested that lymphocystis cysts, known to be caused by iridovirus infection, could be coinfected with the epitheliocystis agent.
Publisher: Elsevier BV
Date: 05-2007
DOI: 10.1016/J.IJPARA.2007.01.003
Abstract: Rapid development of fish culture in marine cages has been associated with an emergence of parasitic diseases. There is a general trend to an increase in infections with ectoparasites with direct life cycles and a reduced ersity of parasites in aquaculture. Some mariculture creates conditions that are similar to serial passage experiments, which are used to study adaptation during experimental evolution of pathogens. In particular, increased density of fish, repeated introduction of naive hosts, homogenous host populations, fast growth and a potential decrease in genetic ersity are attributes of both aquaculture and serial passage experiments. Some free-living organisms, for ex le Neoparamoeba spp. and Uronema spp. parasitise fish in culture, but have not been reported from wild populations. Farming fish in marine cages can increase the risk of outbreaks of parasitic diseases, including those caused by opportunistic parasites. However, aquaculture has the potential to control parasitic diseases through selective breeding, vaccination and general fish health management.
Publisher: Magnolia Press
Date: 03-06-2016
DOI: 10.11646/ZOOTAXA.4119.1.1
Abstract: The genus Cymothoa Fabricius, 1793 is revised for Australian waters. Cymothoa hermani Hadfield, Bruce & Smit, 2011, previously known from Tanzania on the host Selar crumenophthalmus (Bloch, 1793) is new to Australian waters. Cymothoa carangi Avdeev, 1979 Cymothoa epimerica Avdeev, 1979 Cymothoa parupenei Avdeev, 1979 Cymothoa propria Avdeev, 1979 Cymothoa rotunda Avdeev, 1979 and Cymothoa pulchrum Lanchester, 1902 are redescribed. Cymothoa curta Schioedte & Meinert, 1884, first described from the host Anableps anableps (Linnaeus, 1758) and Cymothoa plebeia Schioedte & Meinert, 1884, first described from Cape Verde are redescribed and excluded from the Australian fauna. Cymothoa limbata Schioedte & Meinert, 1884 is placed into junior synonymy with Cymothoa eremita (Brünnich, 1783). A key to the Australian species of Cymothoa is presented.
Publisher: Springer Science and Business Media LLC
Date: 02-08-2021
Publisher: Springer Science and Business Media LLC
Date: 29-05-2022
Publisher: Cambridge University Press (CUP)
Date: 23-12-2010
DOI: 10.1017/S0031182009991703
Abstract: Parasite communities of wild and reared bluefin tuna display remarkable ersity. Among these, the most prevalent and abundant are the Didymozoidae (Monticelli, 1888) (Trematoda, Digenea), considered one of the most taxonomically complex digenean families. The aim of this study was to evaluate phylogenetic structure of Didymozoidae occurring in Pacific ( Thunnus orientalis ) and Atlantic bluefin tuna ( T. thynnus ) in order to increase our knowledge of didymozoid zoogeography and identify species that could successfully be employed as biological tags for stock assessment studies. For the present analyses we used 2 nuclear ribosomal DNA loci, part of the 28S gene and the second internal transcribed spacer (ITS-2) as well as a portion of the mitochondrial cytochrome c oxidase subunit 1 gene ( cox1 ). In most parasitic groups, morphology is the primary factor in the structuring of phylogenetic relationships. In rare ex les, however, habitat has been suggested as a primary factor affecting parasite evolution. During their evolution, didymozoids have spread and inhabited a remarkable number of different sites in their hosts, colonizing exterior as well as strictly interior niches. Our data suggest that habitat selection has been the leading force in shaping didymozoid phylogenetic relationships. For 2 didymozoid species ( D. wedli and D. palati ), cox1 sequences indicate intraspecific differences between Mexican and Adriatic populations.
Publisher: Wiley
Date: 16-08-2015
DOI: 10.1111/JFD.12291
Abstract: Molecular (PCR) diagnostic tests for the detection and identification of aquareovirus in general, and Tasmanian Atlantic salmon reovirus (TSRV) specifically, were developed, and their diagnostic sensitivity and specificity were determined and compared with virus isolation in cell culture. Intralaboratory and interlaboratory comparison of PCR (conventional hemi-nested RT-PCR & RT-qPCR) and virus isolation in cell culture using finfish cell lines, CHSE-214 and EPC, was carried out for the detection and identification of TSRV using field s les of farmed Atlantic salmon Salmo salar, L. from various aquaculture sites around Tasmania. The interlaboratory comparison of diagnostic methods was carried out between two laboratories, AAHL-CSIRO and DPIPWE-Tasmania. A total of 144 fish from nine sites (12-33 fish per site) were s led from two regions of Tasmania (Tamar River estuary in the north and Huon River estuary in the south-east) during late spring to early summer of 2009, and the data were analysed using different statistical approaches. The prevalence of TSRV ranged from 6% to 22% in both regions. All the diagnostic methods (data from both laboratories) had high specificity, while the estimated sensitivity varied between tests with RT-qPCR being the most sensitive (95.2%) method followed by virus isolation and then conventional hemi-nested RT-PCR.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 02-2018
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.DCI.2008.05.013
Abstract: Amoebic gill disease (AGD) is a parasite-mediated proliferative gill disease capable of affecting a range of teleost hosts. While a moderate heritability for AGD resistance in Atlantic salmon has been reported previously, the mechanisms by which in iduals resist the proliferative effects remain poorly understood. To gain more knowledge of this commercially important trait, we compared gill transcriptomes of two groups of Atlantic salmon, one designated putatively resistant, and one designated putatively susceptible to AGD. Utilising a 17k Atlantic salmon cDNA microarray we identified 196 transcripts that were differentially expressed between the two groups. Expression of 11 transcripts were further examined with real-time quantitative RT-PCR (qPCR) in the AGD-resistant and AGD-susceptible animals, as well as non-infected naïve fish. Gene expression determined by qPCR was in strong agreement with the microarray analysis. A large number of differentially expressed genes were involved in immune and cell cycle responses. Resistant in iduals displayed significantly higher expression of genes involved in adaptive immunity and negative regulation of the cell cycle. In contrast, AGD-susceptible in iduals showed higher expression of acute phase proteins and positive regulators of the cell cycle. Combined with the gill histopathology, our results suggest AGD resistance is acquired rather than innately present, and that this resistance is for the most part associated with the dysregulation of immune and cell cycle pathways.
Publisher: Springer Science and Business Media LLC
Date: 27-06-2017
Publisher: Elsevier BV
Date: 03-2013
DOI: 10.1016/J.FSI.2012.12.015
Abstract: A partial sequence of the recombination activating gene-1 (RAG-1) and several full length sequences of the immunoglobulin M (IgM) heavy chain mRNA were obtained from the striped trumpeter (Latris lineata). The RAG-1 fragment consisted of 205 aa and fell within the core region of the open reading frame. The complete IgM heavy chain sequences translated into peptides ranging between 581 and 591 aa. Both genes showed good homology to other vertebrate sequences. The expression of the two genes was assessed throughout the early developmental stages of striped trumpeter larvae (5-100 dph) and used as markers to follow the ontogeny of the adaptive immune response. Using RT-PCR, RAG-1 mRNA expression was detectable at 5 dph and remained so until 80 dph, before becoming undetectable at 100 dph. IgM expression was also detectable at 5 dph, and remained so throughout. These patterns of expression may suggest that the striped trumpeter possess mature B cells with surface IgM at 100 dph. However, complete immunological competence is likely not reached until some time later. The early detection of IgM mRNA at 5 dph led to the investigation of its presence in oocytes. Both RAG-1 and IgM mRNA transcripts were detected in unfertilized oocytes, suggesting that they are maternally transferred. The biological significance of such a phenomenon remains to be investigated.
Publisher: Springer Science and Business Media LLC
Date: 21-04-2011
Publisher: Wiley
Date: 10-2006
DOI: 10.1111/J.1365-2761.2006.00747.X
Abstract: Epitheliocystis is a condition affecting the gills and skin of fish, which has been reported from more than 50 freshwater and marine species. It is caused by intracellular Gram-negative bacteria. Mortalities have been associated with epitheliocystis infections in cultured fish. This review provides an update of our current understanding of this condition, including characterization of the pathogen using immunohistochemical and molecular studies. In most fish species the epitheliocystis agent was negative to an antibody specific for chlamydial genus-specific lipopolysaccharide antigen. Recently, four epitheliocystis agents from four different fish species have been characterized using molecular analysis. While they all belong to the order Chlamydiales, in a lineage separate from the Chlamydiaceae, they are distinct organisms and similarity analysis showed that they had highest similarity values with other chlamydia-like bacteria isolated from various sources, including humans or pig. This confirms the high ersity and host specificity of the pathogen. Further molecular analysis should result in an increased understanding of this condition. To date the pathogen has not been cultured, making experimental studies difficult. High stocking densities, presence of nutrients, season, temperature and fish age have been identified as potential risk factors for the manifestation of this condition.
Publisher: Elsevier BV
Date: 04-2001
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.FSI.2016.09.060
Abstract: Pacific bluefin tuna (PBT), Thunnus orientalis, due to its high average price on the market is an economically valuable fish species. Infections by blood flukes from the genus Cardicola (Trematoda: Aporocotylidae) represent a growing concern for the cage culture of bluefin tuna in Japan, Australia and Southern Europe. The accumulation of numerous Cardicola eggs in the fish gills causes severe pathology that has been linked to mortality in PBT juveniles up to one year old. The only effective treatment used to mitigate the infection is the oral administration of the antihelminthic drug praziquantel (PZQ) to the affected fish. However, with the need to minimise therapeutic drug use in aquaculture it is hoped that immunoprophylaxis can provide a future alternative to protect the PBT juveniles against Cardicola infection. Currently, little is known of the host immune response to these parasites and of their infection dynamics. In this study, using real-time qPCR we aimed to quantitatively detect C. orientalis and C. opisthorchis DNA within the gills and heart of cultured PBT juveniles and to investigate the host immune response at the transcriptional level in the gills. The research focused mainly during early stages of infection soon after young PBT were transferred to culture cages (from 14 to 77 days post-transfer). An increase (up to 11-fold) of immune-related genes, namely IgM, MHC-I, TCR-β and IL-1β was observed in the PBT gills infected with Cardicola spp. (28-77 days post-transfer). Furthermore, IgM (19-fold increase) and MHC-I (11.5-fold increase) transcription was strongly up-regulated in gill s les of PBT infected with C. orientalis relative to uninfected fish but not in fish infected with C. opisthorchis. Cardicola-specific DNA was first detected in the host 14 days post-transfer (DPT) to sea-cages which was 55 days earlier than the first detection of parasite eggs and adults by microscopy. Oral administration of PZQ did not have an immediate effect on parasite DNA presence in the host and the DNA presence started to reduce after 24 days only in the host heart. The results provide evidence of an immune response in early age sea-cage cultured juveniles of PBT naturally infected with C. orientalis and C. opisthorchis. This response, whilst not protective against primary infection, provides evidence that immunisation at an early age may have potential as a health strategy.
Publisher: Elsevier BV
Date: 2005
Publisher: Wiley
Date: 12-2001
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.FSI.2013.10.008
Abstract: Infections by two blood fluke species, Cardicola orientalis and Cardicola opisthorchis, currently present the greatest disease concern for the sea-cage culture of Pacific bluefin tuna (PBT) - a species of high global economic importance and ecological concern. In this study, we aimed to rapidly, quantitatively, and differentially identify infections by these two parasite species in cultured PBT as well as identify potential host immune responses. Using real-time qPCR, we were successful in quantitatively detecting parasite-specific DNA from within host blood, gill, and heart tissues positively identifying parasitic infections 44 days earlier than microscopy methods previously employed. Both gill and heart became heavily infected by both parasite species in PBT within two months of sea-cage culture, which was only mitigated by the administration of anthelmintic praziquantel. Nevertheless, fish were observed to mount an organ specific transcriptive immune response during infection that mirrored the relative quantity of pathogenic load. In heart, significant (3-6 fold) increases in IgM, MHC2, TCRβ, and IL-8 transcription was observed in infected fish relative to uninfected controls whereas in the gills only IgM transcription was observed to be induced (11 fold) by infection. Interestingly, the relative quantity of IgM transcription was highly correlated to the relative abundance of C. orientalis but not C. opisthorchis DNA in the gill s les, even though this organ showed high prevalence of DNA from both parasite species. Taken together, these findings indicate that although ineffective at combating infection during primary exposure, a cellular immune response is mounted in PBT as a potential rejoinder to future Cardicola exposure, particularly against C. orientalis. Although future investigation into antibody effectiveness will be needed, this work provides valuable preliminary insight into host responsiveness to Cardicola infection as well as additional support for the need of anthelmintic treatment following primary parasite exposure during PBT culture.
Publisher: Elsevier BV
Date: 2022
Publisher: Magnolia Press
Date: 05-07-2013
DOI: 10.11646/ZOOTAXA.3683.4.4
Abstract: Ceratothoa carinata (Bianconi, 1869) and Ceratothoa oxyrrhynchaena Koelbel, 1878 are recorded for the first time from Australia and redescribed. Ceratothoa curvicauda Nunomura, 2006 is synonymised with Ceratothoa carinata. Brief accounts are given on the distribution and hosts of these species.
Publisher: CABI Publishing
Date: 25-01-2011
Abstract: Amoebic gill disease (AGD) is a severely debilitating disease, which mainly affects the salmonid industry. It causes high production losses worldwide, including Tasmania, where it is the main health problem in farmed Atlantic salmon. Without the use of control procedures such as fresh water bathing and/or by maintaining fish population densities at a level commensurate with proper hygiene, this disease can often lead to the death of over 50% of infected salmon. AGD is caused by the parasitic amoeba, Neoparamoeba perurans , which binds to and inhabits the gill epithelium of growing fish. Pathology is associated with severe epithelial hyperplasia, fusion of gill lamellae, lowering of oxygen tension and pH of the blood and eventual death of the fish. In order to understand this disease process, research has been carried out, to study the immune response of fish to primary and secondary infections, the genetic basis of resistance to infection as well as how the parasite binds to the host gill tissue and induces a severe host response. Results have shown that N. perurans contains within its surface glycocalyx, high-molecular-weight mucin-like glycoproteins. These surface mucins are immunodominant, according to studies showing that they are the major antigens recognized by antibody in serum from fish exposed to the parasite, as well as when immunized with either whole parasites or subcellular fractions. Thus far, attempts to vaccinate salmon using the purified, high-molecular-weight surface antigen (HMWA) have failed to induce significant protective immunity. However, these studies have greatly aided our understanding of the molecular basis of the amoeba binding and infection process.
Publisher: Elsevier BV
Date: 11-2010
Publisher: Oxford University Press (OUP)
Date: 22-07-2010
DOI: 10.1111/J.1365-2672.2010.04795.X
Abstract: Tenacibaculum maritimum is a well known fish pathogen worldwide, affecting many fish species including Atlantic salmon in Tasmania, Australia. The aim of this study was to characterise and understand the similarities and differences between the isolates in order to select isolates for later pathogenicity and vaccination trials. Several physical characterisation tests were carried out: whole cell protein profiles, lipopolysaccharide profiles (LPS), extracellular product profiles (ECP), indirect immunofluorescent antibody test (IFAT) and hydrophobicity. The Tasmanian strains of T. maritimum appear relatively homogeneous physically, but antigenically different. All isolates were hydrophobic and produce a variety of ECP profiles. There were two isolates that stand out in all assays (89/4747 and 01/0356-7) and showed great variation from the other isolates. All isolates have been confirmed as T. maritimum. Based on the tests carried out three isolates were chosen for in vivo trials: 89/4747, 89/4762, 00/3280. This is the first study to characterise T. maritimum isolates from Tasmanian waters. The opportunity to develop vaccines for the Tasmanian salmonid aquaculture industry is enhanced by a greater understanding of the physical characteristics of pathogens.
Publisher: Elsevier BV
Date: 11-2011
Publisher: Elsevier BV
Date: 06-2021
Publisher: Springer Science and Business Media LLC
Date: 02-11-2017
DOI: 10.1007/S00705-016-3132-0
Abstract: In an attempt to determine whether or not genetic variants of the Tasmanian strain of Atlantic salmon aquareovirus (TSRV) exist, 14 isolates of TSRV, originating from various locations in Tasmania, covering a 20-year period (1990-2010), obtained from various host species and tissues, and isolated on different cell lines, were selected for this study. Two categories, termed "typical" and "atypical", of variants of TSRV were identified based on preliminary genotypic and phenotypic characterization carried out on these 14 different isolates. In addition, electron microscopic examination indicated the existence of at least three variants based on viral particle size. Finally, this study demonstrated the existence of at least one new variant of TSRV isolates, other than the more commonly isolated typical TSRV isolates, in farmed Tasmanian Atlantic salmon.
Publisher: Wiley
Date: 27-11-2006
Publisher: Elsevier BV
Date: 05-2007
Publisher: Elsevier BV
Date: 11-2004
Publisher: Wiley
Date: 21-06-2018
DOI: 10.1111/JFD.12839
Abstract: Finfish with asymptomatic Yersinia ruckeri infections pose a major risk as they can transmit the pathogen and cause clinical outbreaks in stock populations. Current tools have insufficient quantitative ability for accurately detecting the trace levels of Y. ruckeri typically associated with asymptomatic infection, necessitate invasive or lethal s ling, or require long processing times. This study presents a highly sensitive qPCR-based method, targeting part of the Y. ruckeri 16S rRNA sequence, that is capable of detecting extremely low levels of Y. ruckeri in noninvasively collected faecal s les. Quantitative precision and accuracy of faecal s le analysis was consistent, despite the complexity of the faecal matrix. The assay demonstrated linearity over a six log-wide dynamic range. Its limit of detection (LOD) and limit of quantification (LOQ) were 4 and 10 copies of the target sequence, respectively. Sensitivity of the assay was comparable to other qPCR-based methods without requiring invasive or lethal s ling. Applicability as a screening strategy was tested using passively collected faecal s les. Asymptomatic Y. ruckeri infection was detected in all s les, although none of the fish exhibited overt infection. This method will be beneficial for finfish disease management if developed further as a noninvasive, screening tool against asymptomatic Y. ruckeri infection.
Publisher: Frontiers Media SA
Date: 29-03-2017
Publisher: Wiley
Date: 05-2005
DOI: 10.1111/J.1365-2761.2005.00633.X
Abstract: An experiment was conducted to determine the effect of Neoparamoeba sp. infection on the innate immune responses of Atlantic salmon. Atlantic salmon were experimentally infected with Neoparamoeba sp. and serially s led 0, 1, 4, 6, 8 and 11 days post-exposure (dpe). Histological analysis of infected fish gill arches identified the presence of characteristic amoebic gill disease lesions as early as 1 dpe with a steady increase in the number of affected gill filaments over time. Immune parameters investigated were anterior kidney phagocyte function (respiratory burst, chemotaxis and phagocytosis) and total plasma protein and lysozyme. In comparison with non-exposed control fish basal respiratory burst responses were suppressed at 8 and 11 dpe, while phorbol myristate acetate-stimulated activity was significantly suppressed at 11 dpe. Variable differences in phagocytic activity and phagocytic rate following infection were identified. There was an increase in the chemotactic response of anterior kidney macrophages isolated from exposed fish relative to control fish at 8 dpe. Total protein and lysozyme levels were not affected by Neoparamoeba sp. exposure.
Publisher: Wiley
Date: 06-2003
Publisher: Elsevier BV
Date: 07-2000
DOI: 10.1016/S0141-1136(00)00253-1
Abstract: Non-specific immune response of greenback flounder, Rhombosolea tapirina, exposed to contaminated marine sediments was examined. Reference sediments from Port Sorell and contaminated sediments from Deceitful Cove, Tasmania, Australia were investigated. Hatchery-reared flounder were exposed to reference sediment, contaminated sediment or contaminated sediment and diet for 6 weeks. Phagocytic capacity and lysozyme response in flounder were examined on cessation of exposure trial. Significant differences were found in phagocytic capacity and lysozyme response between treatments. Exposure to contaminated sediment, irrespective of diet or benthic disturbance elicited inhibition of phagocytic efficiency in flounder. Disturbance of contaminated sediment stimulated lysozyme activity. The immune response in flounder indicates potential immunotoxicity of sediment from Deceitful Cove.
Publisher: Wiley
Date: 15-05-2019
DOI: 10.1111/JFD.13016
Abstract: There are limited reports of infectious agents affecting Australian cowtail stingrays. In the present study, a new species of ascaridoid nematode belonging to the genus Mawsonascaris is described. The most distinct characteristic features were observed in females (the presence of a polar spine in the eggs and a flap-like projection in the vulval area). An identification key for Mawsonascaris spp. is provided. Additionally, internal transcribed spacers (ITS) sequences were obtained for the new species. Alignment of the ITS sequence of the specimens in the present study with those deposited in GenBank showed that there exists no other highly similar sequence. Phylogenetic analyses resulted in a distinct grouping of our specimens supporting morphological distinction from previously described Mawsonascaris spp. Histology was used to investigate the pathology caused by the infection. Necrosis, inflammation and fibrosis were evident at the border of the nodules formed by parasite. A large number of parasites were present in muscularis mucosae and submucosa but not in the muscularis of the stomach. The parasites were associated with an increased inflammatory response, which was also found in the muscularis mucosae and submucosa. Similar pathology has been described in elasmobranchs infected by cestodes, although with more severe lesions.
Publisher: Wiley
Date: 25-06-2018
DOI: 10.1111/JFD.12834
Abstract: Freshwater bathing is one of the main treatment options available against amoebic gill disease (AGD) affecting multiple fish hosts in mariculture systems. Prevailing freshwater treatments are designed to be long enough to kill Neoparamoeba perurans, the ectoparasite causing AGD, which may select for freshwater tolerance. Here, we tested whether using shorter, sublethal freshwater treatment durations are a viable alternative to lethal ones for N. perurans (2-4 hr). Under in vitro conditions, gill-isolated N. perurans attached to plastic substrate in sea water lifted off after ≥2 min in freshwater, but survival was not impacted until 60 min. In an in vivo experiment, AGD-affected Atlantic salmon Salmo salar subjected daily to 30 min (sublethal to N. perurans) and 120 min (lethal to N. perurans) freshwater treatments for 6 days consistently reduced N. perurans cell numbers on gills (based on qPCR analysis) compared to daily 3 min freshwater or seawater treatments for 6 days. Our results suggest that targeting cell detachment rather than cell death with repeated freshwater treatments of shorter duration than typical baths could be used in AGD management. However, the consequences of modifying the intensity of freshwater treatment regimes on freshwater tolerance evolution in N. perurans populations require careful consideration.
Publisher: Elsevier BV
Date: 10-2010
DOI: 10.1016/J.VETPAR.2010.06.007
Abstract: Peaks in epizootics of sea lice (mostly Caligus chiastos) and blood flukes (Cardicola forsteri) among Southern Bluefin tuna (Thunnus maccoyii) appear to coincide with the onset of an increased mortality. The mortality event occurs 6-12 weeks after T. maccoyii have been transferred into static ranching pontoons from the wild. However, to date available data on parasite occurrence before commercial harvesting begins, are scant. This research gathered epizootiological data from weeks 4 to 13 post-transfer, for 153 T. maccoyii s led from two research and four commercial pontoons. Counts of both parasites in the research pontoons reached levels far heavier than previously documented in ranched T. maccoyii. For sea lice, the prevalence in most pontoons was 100% the highest intensity reached 495 in iduals, and mean counts at the peak of the infection exceeded 265 lice per fish. Almost all of the 5407 in idual lice counted were identified as adult C. chiastos (89.44% female, 10.14% male) adult females of two other species were also present, C. amblygenitalis (0.13%), in addition to an undescribed species, C. sp. (0.04%). Lice counts were correlated positively with gross eye pathology scores (r(s,151df)=0.3394, p=0.0000), negatively correlated with condition index (r(s,151df)=-0.5396, p=0.0000), and positively correlated with plasma cortisol (r(s,131df)=0.3906, p=0.0000) and glucose (r(s,131df)=0.2240, p=0.0096). For the blood fluke, prevalences were less uniform than those of sea lice, with lower rates of infection at the beginning (ranging from 10% to 40%), reaching 100% mid-study, and declining again (40% in one pontoon). The highest intensity reached 441 in idual flukes. Fluke counts were negatively correlated with plasma haemoglobin (r(s,151df)=-0.2436, p=0.0051) and positively with lysozyme (r(s,151df)=0.3013, p=0.0019). Fluke counts were also correlated with sea lice counts (r(s,150df)=0.3143, p=0.0000). Peaks in these epizootics occurred near the onset of elevated mortalities, which started after 7 weeks of ranching.
Publisher: Inter-Research Science Center
Date: 2004
DOI: 10.3354/DAO058063
Abstract: The green crab Carcinus maenas was introduced to Australian temperate waters in the late 1800s, has since become established, and is now considered to be a pest. We undertook an extensive parasite survey to find potential natural enemies of C. maenas and found it to be infected in Australia by 2 species of larval trypanorhynch tapeworm, Trimacracanthus aetobatidis and Dollfusiella martini. We describe the gross pathology and histopathology of the parasites' new host (C. maenas) and note that the plerocercoid larvae are located in the lumen of the digestive gland tubules. The presence of D. martini in C. maenas with low population numbers suggests that either D. martini has an impact (direct or indirect) on the survival of C. maenas, or that the parasite may be an indicator of high predation pressure. If the former were true, this would contribute to the control of this introduced pest species.
Publisher: Wiley
Date: 1997
Publisher: Elsevier BV
Date: 10-2001
DOI: 10.1016/S0166-445X(01)00146-1
Abstract: Pathological abnormalities and mixed function oxygenase (MFO) enzyme changes are frequently used as indicators of anthropogenic contaminant exposure and effect. However, there is a paucity of research investigating the effects of contaminated sediment on native Australian benthic teleosts. As part of an ecotoxicological assessment of contaminated marine sediments in northern Tasmania, CYP1A induction, histological and growth response of the greenback flounder, Rhombosolea tapirina, exposed to contaminated marine sediments were examined. Hatchery reared flounder were exposed to reference sediment, contaminated sediment or contaminated sediment and diet for 6 weeks. CYP1A induction, using the ethoxyresorufin-O-deethylase (EROD) assay, and the histological and growth response in the flounder were examined on cessation of the exposure trial. Significant differences were found between treatments in histological, growth and EROD response. Exposure to contaminated sediment and diet elicited a multi-organ histological response: principally partial and total epidermal erosion and multifocal necrosis of the liver. The prevalence of total epidermal erosion was greatest with exposure to disturbed contaminated sediment (66.65+/-16.65%). The prevalence of multifocal necrosis of the liver was greatest with exposure to contaminated sediment and diet (66.65+/-16.65%). Growth reduction, measured as percentage growth inhibition, was evident in flounder exposed to contaminated sediment and diet (18.2+/-11.99%). Additionally, exposure to contaminated sediment and diet elicited elevated induction of the EROD liver detoxification enzyme (139.65+/-24.22 pmol/min/mg protein) compared to exposure to contaminated sediment and non-contaminated diet (6.25+/-0.81 pmol/min/mg) indicating the presence and potential bioavailability of xenobiotics via food. Further, more inhibited growth and histological alteration associated with exposure to contaminated sediment and diet suggest contaminants in Deceitful Cove sediment are cytotoxic.
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.SCITOTENV.2019.04.412
Abstract: Previous studies of sculpins from the former lead (Pb) - zinc (Zn) mine near Maarmorilik, West Greenland, have shown that these fish are affected by heavy metal exposure from the mine. In this study, we applied mucosal mapping (a stereological method for mucosal quantification in fish) to uncover interactions between the host, parasites and heavy metal exposure (Pb and Zn) in shorthorn sculpins from the Maarmorilik mining site at a gradient of 3 stations. Skin and gill mucosal epithelia of shorthorn sculpins were significantly affected and reflected the exposure to environmental heavy metals and parasites. Size of skin mucous cells was significantly smallest in the sculpin from the station 3 where heavy metal contamination was lowest and the skin parasite load was highest. Gill filament mucous cells were largest and densest in fish from station 1 which was the most contaminated site. In gill lamellae the density of mucous cell followed a toxicity gradient and was significantly highest at the most contaminated station and significantly lowest at the least contaminated station. The persistent presence of toxic Pb and Zn levels in the sediment at the most contaminated station may have induced a small but measurable reduction in the surface area available for respiration and may have affected diffusion distance. The strong correlation between size of filamentous mucous cells and Pb concentrations in liver suggests that these cells can play an active role in reducing the somatic load of Pb in sculpin. We suggest that mucosal mapping can be used to assess effects of contaminant and parasite exposure in future environmental field studies.
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.TICE.2019.02.003
Abstract: Melanomacrophage centres (MMCs) are distinct aggregations of pigment-containing cells in internal organs of fish, hibians and reptiles. Although MMCs are commonly used as biomarkers for anthropogenic exposure in many environmental monitoring programs, a substantial knowledge on characteristics of MMCs is required prior to the assessment of MMC responses. The present study was the first to determine the 3D structure of splenic MMCs of a fish from a number of consecutive histology sections by use of the Fiji and AutoCad software. Most splenic MMCs of shorthorn sculpins (Myoxocephalus scorpius) had spherical shape and limited variation in size (maximum diameter). We confirmed the close relationship between MMCs and blood vessels in spleen of shorthorn sculpins as 97% of investigated MMCs (60 whole MMCs over 510 μm thickness of the s les) were closely associated with splenic blood capillaries (mainly ellipsoids) at least once in a set of consecutive sections. In this paper, we describe variations in morphology, density, size, area, distribution, pigments and response to pathogens of MMC populations from different organs (spleen, kidney, liver, pancreas and gills). Additionally, we provide evidence suggesting the presence and dominance of pheomelanin in MMCs of shorthorn sculpins.
Publisher: Inter-Research Science Center
Date: 2005
DOI: 10.3354/DAO066135
Abstract: Amoebic gill disease (AGD) affects the culture of Atlantic salmon Salmo salar in the southeast of Tasmania. The disease is characterised by the presence of epizoic Neoparamoeba spp. in association with hyperplastic gill tissue. Gill-associated amoebae trophozoites were positively selected by plastic adherence for culture in seawater, where they proliferated using heat-killed E. coli as a nutrient source. One isolate of gill-harvested amoebae designated NP251002 was morphologically consistent to N. pemaquidensis under light, fluorescence and transmission electron microscopy. Rabbit anti-N. pemaquidensis antiserum bound to NP251002, and N. pemaquidensis small subunit (SSU) ribosomal DNA (18S rDNA) was detected in NP251002 genomic DNA preparations using PCR. A high degree of similarity in the alignment of the NP251002 18S rDNA PCR licon sequence with reference isolates of N. pemaquidensis suggested conspecificity. While short-term culture (72 h) of gill-harvested amoebae does not affect the capacity of amoebae to induce AGD, Atlantic salmon challenged with NP251002 after the trophozoites had been 34 and 98 d in culture exhibited neither gross nor histological evidence of AGD. It is not known if NP251002 were avirulent at the time of isolation, had down-regulated putative virulence factors or virulence was inhibited by the culture conditions. Therefore, the time in culture could be a limiting factor in maintaining virulence using the culture technique described here.
Publisher: Cambridge University Press (CUP)
Date: 25-10-2018
DOI: 10.1017/S0031182018001774
Abstract: Trichodinids are parasites generally found on gills and skin of a broad number of aquatic animals. Only a small number of endozoic species has been reported from the urinary tract, intestine and urogenital system in some fish, hibians and molluscs. This is the first report on the presence of endozoic trichodinids in the spleen, kidney and liver of shorthorn sculpin ( Myoxocephalus scorpius ). In the present study, trichodinids displayed some of the typical morphological characteristics of endozoic trichodinids with narrow blades and straight rays of adhesive disc denticles. The parasites were observed at a relatively high prevalence (23.9%). There was a positive correlation between intensity of endozoic trichodinids in the internal organs and ectozoic trichodinids on the gills ( R = 0.5, n = 46, P 0.001) whereas there was no correlation between intensity of endozoic trichodinids and the host's body length, body weight or liver weight. Infection levels of endozoic trichodinids were not dependent upon sculpin sex and there was no effect of s ling locations on prevalence and intensity of endozoic trichodinids.
Publisher: Wiley
Date: 16-07-2009
Publisher: Elsevier BV
Date: 04-2002
DOI: 10.1016/S0145-305X(01)00070-2
Abstract: In order to perform specific immunological assays we have produced and characterised three monoclonal antibodies (MAbs) that bind snapper (Pagrus auratus, Bloch and Schneider) immunoglobulin (Ig). Hybridomas were produced and screened for anti-Ig production using ELISA, Western blot and flow cytometry. All three MAbs (designated 2C5, 4A2 and 1C6) bound specifically to the heavy (H) chain of reduced Ig in Western blot. Furthermore, 1C6 was shown to bind to reduced skin mucus Ig H chain and all three MAbs cross-reacted with the H chain of Atlantic salmon and rainbow trout Ig. In flow cytometric analyses 2C5 and 4A2 bound to B cell populations in the peripheral blood and lymphoid organs. Furthermore, cross-linked 2C5 induced an increase in intracellular protein tyrosine phosphorylation in peripheral blood lymphocytes. Phosphorylated proteins exhibited similar molecular weights to those of mammalian Igalpha and Igbeta and may represent snapper mIg accessory molecule analogues. These data exhibit the potential use of 2C5, 4A2 and 1C6 in both cellular and biochemical analyses of populations of snapper leucocytes.
Publisher: Wiley
Date: 03-2000
Publisher: Springer Science and Business Media LLC
Date: 07-2002
DOI: 10.1007/S00244-002-1184-5
Abstract: Hepatic copper levels may not indicate short-term exposure to waterborne copper in teleosts. Significantly higher copper loads were found in the gills of rainbow trout exposed to 105 microg x L(-1) total measured copper for a period of 24 h than in control animals where no differences were recorded in hepatic copper levels. A second experiment exposing trout to 153 microg x L(-1) total measured copper also demonstrated significant differences in branchial copper levels between control and exposed animals after 3 h exposure. The ratio of the copper load in the gills to the liver, and copper/zinc ratios of the gills were also examined. After exposure to 105 microg x L(-1) for 24 h both gill/liver copper ratios and Cu/Zn ratios in exposed animals were significantly greater than in control animals. After 12 h exposure to 153 microg x L(-1) total measured copper the gill Cu/Zn ratio was significantly greater than in control animals. These data indicate the gills may be a better indicator of short-term exposure than the liver.
Publisher: Wiley
Date: 03-2001
Publisher: Wiley
Date: 08-03-2021
DOI: 10.1111/JFD.13363
Abstract: Amoebic gill disease (AGD) is a significant issue in Atlantic salmon mariculture. Research on the development of treatments or vaccines uses experimental challenges where salmon is exposed to amoebae concentrations ranging from 500 to 5,000/L. However, the water concentrations of N. perurans on affected salmon farms are much lower. The lowest concentration of N. perurans previously reported to cause AGD was 10/L. Here, we report that concentrations as low as 0.1/L of N. perurans can cause AGD. We propose that concentrations of N. perurans that reflect those measured on salmon farms should be used for future experimental challenges.
Publisher: Springer Science and Business Media LLC
Date: 26-06-2021
Publisher: Elsevier BV
Date: 11-2020
Publisher: Wiley
Date: 09-2006
DOI: 10.1111/J.1365-2761.2006.00751.X
Abstract: There is inconsistent evidence of resistance of Atlantic salmon, Salmo salar L., to amoebic gill disease (AGD). Here, evidence is presented that demonstrates that Atlantic salmon exposed and subsequently challenged with AGD are more resistant than naïve control fish. Seventy-three per cent of Atlantic salmon previously exposed to AGD survived to day 35 post-challenge compared with 26% exposed to Neoparamoeba sp. for the first time, yet the gill pathology of surviving naïve control or previously exposed fish was not significantly different. Development of resistance to AGD is associated with anti-Neoparamoeba sp. antibodies that were detectable in serum of 50% of surviving Atlantic salmon previously exposed to AGD. However, anti-Neoparamoeba sp. antibodies were not detectable in cutaneous mucus of resistant fish. Increased resistance of Atlantic salmon after secondary Neoparamoeba sp. infection and detection of specific serum antibodies provides support for the development of a vaccine for AGD.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Elsevier BV
Date: 04-2003
Publisher: Elsevier BV
Date: 04-2006
Publisher: Wiley
Date: 02-2004
DOI: 10.1111/J.1365-2761.2004.00522.X
Abstract: Amoebic gill disease (AGD) has been attributed to infection by Neoparamoeba sp. The causal mechanisms for AGD lesion development and the primary pathogenic role of Neoparamoeba sp. require elucidation. Three groups of Atlantic salmon were exposed to viable gill isolated amoebae, to sonicated amoebae, or to sea water containing viable amoebae without direct contact with gill epithelia. Fish were removed 8 days post-exposure and the gills assessed histologically for AGD. AGD occurred only when fish were exposed to viable trophozoites. Consequently, in an accompanying experiment, infection was evaluated histologically at 12, 24 and 48 h post-exposure in three groups of salmon, one group being mechanically injured 12 h prior to exposure. A progressive host response and significant increase (P < 0.001) in the numbers of attached amoebae was apparent over the 48-h duration in undamaged hemibranchs in both treatment groups. There were no significant differences to mucous cell populations. Attachment of Neoparamoeba sp. to damaged gill filaments was significantly reduced (P < 0.05) by 48 h post-exposure. These data further confirm and describe the primary pathogenic role of Neoparamoeba sp. and the early host response in AGD. Preliminary evidence suggests that lesions resulting from physical gill damage are not preferentially colonized by Neoparamoeba sp.
Publisher: Springer International Publishing
Date: 2019
Publisher: Elsevier BV
Date: 05-2022
DOI: 10.1016/J.FSI.2022.03.024
Abstract: Little is known about host responses of farmed Chinook salmon with skin lesions, despite the lesions being associated with increased water temperatures and elevated mortality rates. To address this shortfall, a transcriptomic approach was used to characterise the molecular landscape of spot lesions, the most commonly reported lesion type in New Zealand Chinook salmon, versus healthy appearing skin in fish with and without spot lesions. Many biological (gene ontology) pathways were enriched in lesion adjacent tissue, relative to control skin tissue, including proteolysis, fin regeneration, calcium ion binding, mitochondrial transport, actin cytoskeleton organisation, epithelium development, and tissue development. In terms of specific transcripts of interest, pro-inflammatory cytokines (interleukin 1β and tumour necrosis factor), annexin A1, mucin 2, and calreticulin were upregulated, while cathepsin H, mucin 5AC, and perforin 1 were downregulated in lesion tissue. In some instances, changes in gene expression were consistent between lesion and healthy appearing skin from the same fish relative to lesion free fish, suggesting that host responses weren't limited to the site of the lesion. Goblet cell density in skin histological sections was not different between skin s le types. Collectively, these results provide insights into the physiological changes associated with common spot lesions in farmed Chinook salmon.
Publisher: Wiley
Date: 10-2005
Publisher: Wiley
Date: 06-2005
DOI: 10.1111/J.1365-2761.2005.00636.X
Abstract: Previous studies have demonstrated that beta-glucans stimulate Atlantic salmon, Salmo salar L., head kidney macrophages both in vitro and in vivo and increase protection against various pathogens. Based on our previous work that showed potent immunostimulatory CpG motif-containing oligodeoxynucleotides increased resistance to amoebic gill disease (AGD), the present study investigated the immunostimulatory effects of three commercial beta-glucan-containing feeds and their ability to increase resistance to AGD. All three commercial beta-glucans were able to stimulate the respiratory burst activity of Atlantic salmon head kidney macrophages in vitro, albeit at different times and concentrations. However, dietary incorporation of the beta-glucans was unable to stimulate the in vivo respiratory burst activity of head kidney macrophages, or serum lysozyme production, and did not increase resistance against AGD. However, this trial showed for the first time that a small subpopulation of Atlantic salmon subjected to a severe AGD infection was able to resist becoming heavily infected and furthermore survive the challenge.
Publisher: Wiley
Date: 18-02-2022
DOI: 10.1111/JFD.13598
Publisher: Inter-Research Science Center
Date: 08-02-2007
DOI: 10.3354/DAO074057
Abstract: We characterised 9 strains selected from primary isolates referable to Paramoeba/Neoparamoeba spp. Based on ultrastructural study, 5 strains isolated from fish (amoebic gill disease [AGD]-affected Atlantic salmon and dead southern bluefin tuna), 1 strain from netting of a floating sea cage and 3 strains isolated from invertebrates (sea urchins and crab) were assigned to the genus Neoparamoeba Page, 1987. Phylogenetic analyses based on SSU rDNA sequences revealed affiliations of newly introduced and previously analysed Neoparamoeba strains. Three strains from the invertebrates and 2 out of 3 strains from gills of southern bluefin tunas were members of the N. branchiphila clade, while the remaining, fish-isolated strains, as well as the fish cage strain, clustered within the clade of N. pemaquidensis. These findings and previous reports point to the possibility that N. pemaquidensis and N. branchiphila can affect both fish and invertebrates. A new potential fish host, southern bluefin tuna, was included in the list of farmed fish endangered by N. branchiphila. The sequence of P. eilhardi (Culture Collection of Algae and Protozoa [CCAP] strain 1560/2) appeared in all analyses among sequences of strain representatives of Neoparamoeba species, in a position well supported by bootstrap value, Bremer index and Bayesian posterior probability. Our research shows that isolation of additional strains from invertebrates and further analyses of relations between molecular data and morphological characters of the genera Paramoeba and Neoparamoeba are required. This complexity needs to be considered when attempting to define molecular markers for identification of Paramoeba/Neoparamoeba species in tissues of fish and invertebrates.
Publisher: Public Library of Science (PLoS)
Date: 25-08-2011
Publisher: Public Library of Science (PLoS)
Date: 12-07-2012
Publisher: Wiley
Date: 03-2004
DOI: 10.1111/J.1365-2761.2004.00531.X
Abstract: Freshwater bathing is essential for control of amoebic gill disease (AGD) during the marine phase of the Tasmanian Atlantic salmon production cycle, a practice that is costly, production limiting and increasing in frequency. Although the pathogenesis of gill infection with Neoparamoeba sp. in naïve Atlantic salmon, Salmo salar, is now understood, the progression of re-infection (post-treatment) required elucidation. Here, we describe the weekly histopathological progression of AGD from first to second freshwater bath. Halocline cessation and increased water temperature appeared to drive the rapid onset of initial infection prior to bathing. Freshwater bathing cleared lesions of attached trophozoites and associated cellular debris. Subsequent gill re-infection with Neoparamoeba sp. was evident at 2 weeks post-bath and had significantly increased (P < 0.001), in severity by 4 weeks post-bath. No significant difference in gross pathology was observed until 4 weeks post-bath (P < 0.05). The re-infective progression of AGD was characterized by localized host tissue responses juxtaposed to adhered trophozoites (epithelial oedema, hypertrophy and hyperplasia), non-specific inflammatory cell infiltration (macrophages, neutrophils and eosinophilic granule cells) and finally advanced hyperplasia with epithelial fortification. During the post-bath period, non-AGD lesions including haemorrhage, necrosis and regenerative hyperplasia were occasionally observed, although no evidence of secondary colonization of these lesions by Neoparamoeba sp. was noted. We conclude that pathogenesis during the inter-bath period was identical to initial infection although the source of re-infection remains to be established.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.CBPA.2019.01.012
Abstract: The most capricious environmental variable in aquatic habitats, dissolved O
Publisher: Wiley
Date: 14-06-2014
DOI: 10.1111/JFD.12133
Publisher: Wiley
Date: 05-11-2013
DOI: 10.1111/JFD.12012
Abstract: The use of swabs relative to organs as a s le collection method for the detection of Tasmanian salmon reovirus (TSRV) in farmed Tasmanian Atlantic salmon, Salmo salar L., was evaluated by RT-qPCR. Evaluation of in idual and pooled s le collection (organs vs swabs) was carried out to determine the sensitivity of the collection methods and the effect of pooling of s les for the detection of TSRV. Detection of TSRV in in idual s les was as sensitive when organs were s led compared to swabs, and in pooled s les, organs demonstrated a sensitivity of one 10-fold dilution higher than s ling of pooled swabs. Storage of swabs at 4 °C for t = 24 h demonstrated results similar to those at t = 0. Advantages of using swabs as a preferred s le collection method for the detection of TSRV compared to organ s les are evident from these experimental trials.
Publisher: Wiley
Date: 17-10-2013
DOI: 10.1111/JFB.12235
Abstract: Laser-capture microdissection and immunohistochemistry were used to show that gene and protein expression varied in different cell types in the gills of Atlantic salmon Salmo salar, with chloride cells found to express high levels of sodium potassium ATPase and mucous cells expressing elevated levels of anterior gradient protein. It is therefore important that studies of gene expression in gill tissue take account of the proportion of the various cell types present.
Publisher: Elsevier BV
Date: 11-2007
DOI: 10.1016/J.IJPARA.2007.04.018
Abstract: Amoebic gill disease (AGD) is a potentially fatal disease of some marine fish. Two hizoic amoebae Neoparamoeba pemaquidensis and Neoparamoeba branchiphila have been cultured from AGD-affected fish, yet it is not known if one or both are aetiological agents. Here, we PCR lified the 18S rRNA gene of non-cultured, gill-derived (NCGD) amoebae from AGD-affected Atlantic salmon (Salmo salar) using N. pemaquidensis and N. branchiphila-specific oligonucleotides. Variability in PCR lification led to comparisons of 18S rRNA and 28S rRNA gene sequences from NCGD and clonal cultured, gill-derived (CCGD) N. pemaquidensis and N. branchiphila. Phylogenetic analyses inferred from either 18S or 28S rRNA gene sequences unambiguously segregated a lineage consisting of NCGD amoebae from other members of the genus Neoparamoeba. Species-specific oligonucleotide probes that hybridise 18S rRNA were designed, validated and used to probe gill tissue from AGD-affected Atlantic salmon. The NCGD amoebae-specific probe bound AGD-associated amoebae while neither N. pemaquidensis nor N. branchiphila were associated with AGD-lesions. Together, these data indicate that NCGD amoebae are a new species, designated Neoparamoeba perurans n.sp. and this is the predominant aetiological agent of AGD of Atlantic salmon cultured in Tasmania, Australia.
Publisher: Wiley
Date: 06-2011
DOI: 10.1111/J.1095-8649.2011.03019.X
Abstract: Ranched southern bluefin tuna Thunnus maccoyii were fed baitfishes supplemented with vitamins (predominantly E and C) or vitamins and immunostimulants, nucleotides and β-glucans, over 12 weeks after transfer and monitored for enhancement in immune response, health and performance through their 19 week grow-out period. Fish from two different tows were s led separately at three different s ling points: at transfer to grow-out pontoons, at 8 weeks post-transfer and at harvest, 19 weeks post-transfer. Lysozyme activity was enhanced during vitamin supplementation compared to control fish. Performance (i.e. survival, condition index and crude fat), health (i.e. blood plasma variables including pH, osmolality, cortisol, lactate and glucose) and alternative complement activity were not commonly improved through diet supplementation. There were some tow-specific improvements in performance through vitamin supplementation including survival, selected parasite prevalence and intensity, and alternative complement activity. Immunostimulant supplementation also showed a tow-specific improvement in plasma cortisol level. Tow-specific responses may suggest that life history, previous health condition and husbandry can affect the success of vitamin and immunostimulant enhancement of immune response, health and performance of ranched T. maccoyii.
Publisher: Elsevier BV
Date: 04-2016
Publisher: Wiley
Date: 14-06-2001
Publisher: CSIRO Publishing
Date: 1996
DOI: 10.1071/MF9960255
Abstract: Calculi were observed in the urinary tracts of a wide range of intensively reared marine fish larvae at the Port Stephens Research Centre. Data are presented for three species: snapper Pagrus auratus, mulloway Argyrosomus hololepidotus, and Australian bass Macquaria novemaculeata. Calculi first appeared in P. auratus on Day 5 after hatching, in M. novemaculeata on Day 11, and in A. hololepidotus on Day 12. Around 80% of larvae typically had calculi after two weeks of intensive rearing. No relationship could be found between the absence of the functional swim bladder and the presence of calculi in all species studied. The presence of calculi did not stop the larvae of any species from actively feeding on live prey. Calculi from M. novemaculeata and P. auratus were analysed with an electron probe microanalyser. Phosphorus and calcium were detected in all calculi, usually accompanied by magnesium. Potential causes for the formation of calculi are discussed.
Publisher: Inter-Research Science Center
Date: 24-01-2008
DOI: 10.3354/DAO01869
Abstract: Previously we described a new member of the Neoparamoeba genus, N. perurans, and showed that it is an agent of amoebic gill disease (AGD) of Atlantic salmon Salmo salar cultured in southeast Tasmania, Australia. Given the broad distribution of cases of AGD, we were interested in extending our studies to epizootics in farmed fish from other sites around the world. Oligonucleotide probes that hybridise with the 18S rRNA of N. perurans, N. branchiphila or N. pemaquidensis were used to examine archival s les of AGD in Tasmania as well as s les obtained from 4 host fish species cultured across 6 countries. In archival s les, N. perurans was the only detectable amoeba, confirming that it has been the predominant aetiological agent of AGD in Tasmania since epizootics were first reported. N. perurans was also the exclusive agent of AGD in 4 host species across 6 countries. Together, these data show that N. perurans is a cosmopolitan agent of AGD and, therefore, of significance to the global mariculture industry.
Publisher: Elsevier BV
Date: 03-2004
Publisher: Elsevier BV
Date: 02-2007
Publisher: Oxford University Press (OUP)
Date: 14-11-2017
Abstract: With recent technologies making it possible for commercial scale closed life-cycle aquaculture production of spiny lobster (Panulirus ornatus) comes a strong impetus to further understand aspects of lobster health. The gut microbiome plays a crucial role in host health, affecting growth, digestion, immune responses and pathogen resistance. Herein we characterise and compare gut microbiomes across different developmental stages (6-7 days post-emergence [dpe], 52 dpe and 13 months post-emergence [mpe]) and gut regions (foregut, midgut and hindgut) of cultured P. ornatus juveniles. Gut s les were analysed using 16S rRNA next-generation sequencing. Core gut microbiomes of P. ornatus comprised the phyla Tenericutes and Proteobacteria. Within class Gammaproteobacteria, families Pseudoalteromonadaceae and Vibrionaceae were dominant members across the majority of the gut microbiomes. Characterisation of bacterial communities from 13 mpe lobsters indicated that the hindgut microbiome was more erse and compositionally dissimilar to the foregut and midgut. The bacterial composition of the hindgut was more similar among younger juveniles (6-7 dpe and 52 dpe) compared to 13 mpe lobsters. This is the first study to explore gut microbiomes of spiny lobster juveniles. We demonstrate that the composition of the gut microbiome was shaped by gut region, whereas the structure of the hindgut microbiome was influenced by developmental stage.
Publisher: Wiley
Date: 10-2005
DOI: 10.1111/J.1365-2761.2005.00647.X
Abstract: Aquaculture in Tasmania is mostly carried out in estuaries. These estuarine habitats show a great variety and form unique environments in which Neoparamoeba pemaquidensis, the amoebic gill disease (AGD)-causing protozoan, may or may not survive. Tasmania is ided into two zones, one where AGD is present and one where AGD is absent, but any ecological data to rationalize this distribution is lacking. In in vitro trials N. pemaquidensis strains were exposed to different concentrations of ammonium sulphate, copper sulphate, copper sulphate and tannin, and different Neoparamoeba densities, salinities and temperatures. A trial using field water s les investigated the survival of N. pemaquidensis in waters sourced from AGD-free and AGD-positive zones, and water analysis was performed to determine any differences. Significantly decreased protozoan survival was found with exposure to increasing copper sulphate concentrations from 10 to 100,000 microM (P < 0.001), salinity of 15 per thousand (P < 0.001), low Neoparamoeba densities of 625 and 1,250 cells mL(-1) (P = 0.0005), and water sourced from Macquarie Harbour (P < 0.001). The water chemistry of this AGD-free zone showed significantly lower dissolved calcium and magnesium concentrations which may contribute to this area being AGD-free. Understanding of the ecology of N. pemaquidensis will enable better control and prevention strategies for Tasmanian salmon growers.
Publisher: Inter-Research Science Center
Date: 2006
DOI: 10.3354/DAO070001
Abstract: The identification of protozoan and metazoan parasites is traditionally carried out using a series of classical keys based upon the morphology of the whole organism. However, in stained tissue sections prepared for light microscopy, taxonomic features will be missing, thus making parasite identification difficult. This work highlights the characteristic features of representative parasites in tissue sections to aid identification. The parasite ex les discussed are derived from species affecting finfish, and predominantly include parasites associated with disease or those commonly observed as incidental findings in disease diagnostic cases. Emphasis is on protozoan and small metazoan parasites (such as Myxosporidia) because these are the organisms most likely to be missed or mis-diagnosed during gross examination. Figures are presented in colour to assist biologists and veterinarians who are required to assess host arasite interactions by light microscopy.
Publisher: Wiley
Date: 07-06-2018
DOI: 10.1111/JFD.12822
Abstract: Zebrafish has become a popular research model in the last years, and several diseases affecting zebrafish research facilities have been reported. However, only one case of naturally occurring viral infections was described for this species. In 2015, infectious spleen and kidney necrosis virus (ISKNV) was detected in zebrafish from a research facility in Spain. Affected fish showed lethargy, loss of appetite, abnormal swimming, distention of the coelomic cavity and, in the most severe cases, respiratory distress, pale gills and petechial haemorrhages at the base of fins. Cytomegaly was the most relevant histopathological finding in organs and tissues, sometimes associated to degenerative and necrotic changes. ISKNV belongs to the relatively newly defined genus Megalocytivirus, family Iridoviridae, comprising large, icosahedral cytoplasmic DNA viruses. This is the first case of naturally occurring Megalocytivirus infection in zebrafish research facilities, associated with morbidity. The virus has been identified based on both pathologic and genetic evidence, to better understand the pathogenesis of the infection in zebrafish and the phylogenetic relationship with other iridoviruses. Given the ability of megalocytiviruses to cross-species boundaries, it seems necessary to implement stringent biosecurity practices as these infections may invalidate experimental data and have major impact on laboratory and cultured fish.
Publisher: Wiley
Date: 10-2005
Publisher: Wiley
Date: 07-2002
Publisher: Inter-Research Science Center
Date: 2005
DOI: 10.3354/DAO067055
Abstract: The relationship between salmonid gill bacteria and Neoparamoeba sp., the aetiological agent of amoebic gill disease (AGD) was determined in vivo. Fish were ided into 4 groups and were subjected to following experimental infections: Group 1, amoebae only Group 2, Staphylococcus sp. and amoebae Group 3, Winogradskyella sp. and amoebae Group 4, no treatment (control). Fish (Groups 1, 2 and 3) were exposed to potassium permanganate to remove the natural gill microflora prior to either bacterial or amoebae exposure. AGD severity was quantified by histological analysis of gill sections to determine the percentage of lesioned filaments and the number of affected lamellae within each lesion. All amoebae infected groups developed AGD, with fish in Group 3 showing significantly more filaments with lesions than other groups. Typically lesion size averaged between 2 to 4 interlamellar units in all AGD infected groups. The results suggest that the ability of Neoparamoeba sp. to infect filaments and cause lesions might be enhanced in the presence of Winogradskyella sp. The possibility is proposed that the prevalence of more severe AGD is due to the occurrence of Winogradskyella sp. at high concentrations on the gills.
Publisher: Elsevier BV
Date: 2013
DOI: 10.1016/J.VETIMM.2012.10.010
Abstract: This study aimed to assess systemic and mucosal immune responses of Atlantic salmon (Salmo salar) exposed to two protein-hapten antigens - dinitrophenol (DNP) and fluorescein isothiocyanate (FITC) each conjugated with keyhole limpet haemocyanin (KLH) - administered using different delivery strategies. Fish were exposed to the antigens through different routes, and were given a booster 4 weeks post initial exposure. Both systemic and mucosal antibody responses were measured for a period of 12 weeks using an enzyme-linked immunosorbent assay (ELISA). Only fish exposed to both antigens via intraperitoneal (IP) injection showed increased systemic antibody response starting 6 weeks post immunization. No treatment was able to produce a mucosal antibody response however there was an increase in antibody levels in the tissue supernatant from skin explants obtained 12 weeks post immunization from fish injected with FITC. Western blots probed with serum and culture supernatant from skin explants showed a specific response against the antigens. In conclusion, IP injection of hapten-antigen in Atlantic salmon was the best delivery route for inducing an antibody response against these antigens in this species. Even though IP injection did not induce an increase in antibody levels in the skin mucus, there was an increased systemic antibody response and an apparent increase of antibody production in mucosal tissues as demonstrated by the increased level of specific antibody levels in supernatants from the tissue explants.
Publisher: Elsevier BV
Date: 04-2001
Publisher: Elsevier BV
Date: 08-2002
Publisher: Public Library of Science (PLoS)
Date: 27-09-2012
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 05-2018
Abstract: Paramoebae are enigmatic single-celled eukaryotes that can be opportunistic pathogens of marine animals. For ex le, amoebic gill disease ravages farmed salmonids worldwide, causing tens of millions of dollars in losses annually. Although paramoebae can be found associated with animals ranging from fish and lobster to molluscs and sea urchins, how and how often they actually cause disease is unknown. Here we review recent progress towards understanding the biology and ecology of paramoebid species and the eukaryotic endosymbionts that live inside them. Genomic and transcriptomic sequence data serve as a platform upon which future research on paramoebiasis can build.
Publisher: Wiley
Date: 2004
DOI: 10.1046/J.1365-2761.2003.00514.X
Abstract: Previous studies have indicated that Atlantic salmon, Salmo salar L., affected by amoebic gill disease (AGD) are resistant to re-infection. These observations were based upon a comparison of gross gill lesion abundance between previously infected and naïve control fish. Anecdotal evidence from Atlantic salmon farms in southern Tasmania suggests that previous infection does not protect against AGD as indicated by a lack of temporal change in freshwater bathing intervals. Experiments were conducted to determine if previous infection of Atlantic salmon with Neoparamoeba sp. would provide protection against challenge and elucidate the immunological basis of any protection. Atlantic salmon were infected with Neoparamoeba sp. for 12 days then treated with a 4-h freshwater bath. Fish were separated into two groups and maintained in either sea water or fresh water for 6 weeks. Fish were then transferred to one tank with a naïve control group and challenged with Neoparamoeba sp. Fish kept in sea water had lower mortality rates compared with first time exposed and freshwater maintained fish, however, these data are believed to be biased by ongoing mortalities during the sea-water maintenance phase. Phagocyte function decreased over exposure time and freshwater maintained fish demonstrated an increased ability to mount a specific immune response. These results suggest that under the challenge conditions herein described, antigen exposure via infection does not induce protection to subsequent AGD.
Publisher: Wiley
Date: 14-06-2001
Publisher: Elsevier BV
Date: 08-2009
Publisher: Wiley
Date: 1999
Publisher: Wiley
Date: 25-08-2022
DOI: 10.1111/JFD.13694
Abstract: Epitheliocystis, an intracellular bacterial infection in the gills and skin epithelium, has been frequently reported in Atlantic salmon ( Salmo salar ) during freshwater production in a number of countries. This study describes the prevalence and intensity of a natural epitheliocystis infection present in the gills of two strains of Atlantic salmon reared in either a flow‐through (FT) or a recirculation aquaculture system (RAS) in Ireland. Repeated s ling of gills prior to and throughout seawater transfer, histology and quantitative real‐time PCR were used to determine infection prevalence and intensity. Despite no clinical gill disease, and minor histopathological changes, epitheliocystis lesions were identified in histology at all time points. Specific PCR confirmed the presence of Candidatus Clavichlamydia salmonicola in both strains and its number of copies was correlated with intensity of epitheliocystis lesions. A significant interaction between hatchery system and fish strain on the prevalence and intensity of gill epitheliocystis was found both using histological and molecular methods. Specifically, fish from FT had higher prevalence and intensity than RAS reared fish and within FT, the Irish cohort were more affected than Icelandic.
Publisher: Elsevier BV
Date: 04-1998
Publisher: Cambridge University Press (CUP)
Date: 12-04-2023
DOI: 10.1017/S0033291721001434
Abstract: Vaccine hesitancy presents an obstacle to the c aign to control COVID-19. It has previously been found to be associated with youth, female gender, low income, low education, low medical trust, minority ethnic group membership, low perceived risk from COVID-19, use of certain social media platforms and conspiracy beliefs. However, it is unclear which of these predictors might explain variance associated with others. An online survey was conducted with a representative s le of 4343 UK residents, aged 18–75, between 21 November and 21 December 2020. Predictors of vaccine hesitancy were assessed using linear rank-order models. Coronavirus vaccine hesitancy is associated with youth, female gender, low income, low education, high informational reliance on social media, low informational reliance on print and broadcast media, membership of other than white ethnic groups, low perceived risk from COVID-19 and low trust in scientists and medics, as well as (to a much lesser extent) low trust in government. Coronavirus conspiracy suspicions and general vaccine attitudes appear uniquely predictive, jointly explaining 35% of variance. Following controls for these variables, effects associated with trust, ethnicity and social media reliance largely or completely disappear, whereas the effect associated with education is reversed. Strengthening positive attitudes to vaccination and reducing conspiracy suspicions with regards to the coronavirus may have a positive effect on vaccine uptake, especially among ethnic groups with heightened vaccine hesitancy. However, vaccine hesitancy associated with age and gender does not appear to be explained by other predictor variables tested here.
Publisher: Elsevier BV
Date: 09-2001
Publisher: Wiley
Date: 09-2006
DOI: 10.1111/J.1365-2761.2006.00751.X
Abstract: There is inconsistent evidence of resistance of Atlantic salmon, Salmo salar L., to amoebic gill disease (AGD). Here, evidence is presented that demonstrates that Atlantic salmon exposed and subsequently challenged with AGD are more resistant than naïve control fish. Seventy-three per cent of Atlantic salmon previously exposed to AGD survived to day 35 post-challenge compared with 26% exposed to Neoparamoeba sp. for the first time, yet the gill pathology of surviving naïve control or previously exposed fish was not significantly different. Development of resistance to AGD is associated with anti-Neoparamoeba sp. antibodies that were detectable in serum of 50% of surviving Atlantic salmon previously exposed to AGD. However, anti-Neoparamoeba sp. antibodies were not detectable in cutaneous mucus of resistant fish. Increased resistance of Atlantic salmon after secondary Neoparamoeba sp. infection and detection of specific serum antibodies provides support for the development of a vaccine for AGD.
Publisher: Wiley
Date: 06-2005
Publisher: Wiley
Date: 12-2004
DOI: 10.1111/J.1365-2761.2004.00593.X
Abstract: This study surveyed conditions in the gills of wild marine fish in Tasmania to determine potential interactions between wild and cultured fish. Wild marine fish of 12 species were captured from three Atlantic salmon farm sites and three reference sites around Tasmania. The survey concentrated on three species, red cod, Pseudophycis bachus, sand flathead, Platycephalus bassensis, and jack mackerel, Trachurus declivus. Seventy-six per cent of salmon pens contained wild fish species. The number of species found in a pen ranged from one to nine and the number of in iduals ranged from one to 23. Trichodinids were prevalent and occurred on seven of the 13 species examined. Trichodina occurred on the gills of all but one specimen of red cod. Monogenean gill flukes were observed on all three major species s led and were abundant on sand flathead. Other parasites and conditions observed in the survey included metacercariae of digenean trematodes, epitheliocystis and cysts of unknown origin. Infestations of trichodinids on red cod and monogenean gill flukes on sand flathead were significantly more intense at farm sites than at reference sites. Atlantic salmon s led at the same time from the farms were only affected by amoebic gill disease and isopods.
Publisher: Elsevier BV
Date: 12-2010
DOI: 10.1016/J.FSI.2010.07.036
Abstract: Amoebic gill disease can be experimentally induced by the exposure of salmonids to Neoparamoeba spp. freshly isolated from infected fish, while cultured amoebae are non-infective. Results from our previous work suggested that one key difference between infectious and non-infectious Neoparamoeba were the highly glycosylated molecules in the glycocalyx. To characterise these surface glycans or glycoproteins we used a monoclonal antibody (mAb 44C12) specific to a surface molecule unique to infective parasites. This mAb recognised a carbohydrate epitope on a high molecular weight antigen (HMWA) that make up 15-19% of the total protein in a soluble extract of infectious parasites. The HMWA consisted of at least four glycoprotein subunits of molecular weight (MW) greater than 150 kDa that form disulfide-linked complexes of MW greater than 600 kDa. Chemical deglycosylation yielded at least four protein bands of approximate MW 46, 34, 28 and 18 kDA. While a similar HMWA complex was present in non-infective parasites, the glycoprotein subunits were of lower MW and exhibited differences in glycosylation. The four glycoproteins subunits recognised by mAb 44C12 were resistant to degradation by PNGase F, PNGase A, O-glycosidase plus β-1, 4-galactosidase, β-N-acetylglucosaminidase and neuraminidase. The major monosaccharides in the HMWA from infectious parasites were rhamnose, fucose, galactose, and mannose while sialic acids were absent. The carbohydrate portion constituted more than 90% of the total weight of the HMWA from infectious Neoparamoeba spp. Preliminary results indicate that immunisation of salmon with HMWA does not lead to protection against challenge infection rather it may even have an immunosuppressive effect.
Publisher: Wiley
Date: 2000
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.DCI.2004.05.009
Abstract: In mammals the pentraxins, C-reactive protein (CRP) and serum amyloid P component (SAP) are important components of the immune response. Although pentraxins have been isolated from a number of fish species few studies detail their functional immunological role. In this paper we report the establishment of a flow cytometry based assay to measure the phagocytic activity of isolated snapper head kidney leukocytes (HKLs). This assay was then used to examine the ability of a pentraxin-like protein isolated from the serum of snapper (P. auratus) (Sn-PLP) to act as an opsonin. Incubation of snapper head kidney leukocytes (HKL) with FITC-labelled beads resulted in uptake of these particles by approximately 35% of HKLs. Incubation of beads with Sn-PLP enhanced phagocytosis by snapper HKLs in a dose-dependant manner. Enhanced phagocytosis could be inhibited by addition of a rabbit anti-Sn-PLP antibody suggesting that Sn-PLP may act as a ligand for a HKL cell surface receptor. This study provides further evidence toward a functional role for pentraxins in the host defence repertoire of fish.
Publisher: Elsevier BV
Date: 07-2008
DOI: 10.1016/J.FSI.2007.12.010
Abstract: In this study, adaptive immune response was investigated in farmed southern bluefin tuna, Thunnus maccoyii, infected with a sanguinicolid Cardicola forsteri. A cohort (Cohort(2005)) of southern bluefin tuna was s led between March 2005 and August 2006. S les were taken at the transfer of wild caught tuna to sea cages and then at regular intervals. Parasite intensity, abundance and prevalence data were recorded. An ELISA was developed to detect and quantify an antibody response against the blood fluke in southern bluefin tuna serum. Intensity and prevalence of the blood fluke were shown to peak in May 2005 at 10.9 flukes per infected fish (SE=1.72) and 97.5% prevalence and then decreased to low prevalence (10%) and intensity (1.0). There were no significant changes in prevalence or intensity in 2006. Antibody titres and seroprevalence increased from 1.37 U microl(-1) and 10% at transfer in March 2005 to reach a peak in December 2005 of 25.86 U microl(-1) (SE=6.26 U microl(-1)) and 66.66%. No significant changes were observed in antibody titres for the same cohort of fish during 2006. Parasitological and serological values from Cohort(2005) were compared to a 2006 cohort (Cohort(2006)) in March 2006 and August 2006 to determine if prior infection in Cohort(2005) elicited any protection against infection in 2006. Although significant differences were not observed in intensities between cohorts it was shown that Cohort(2005) had significantly lower abundances and prevalences of blood fluke infection than Cohort(2006). Although there was no significant difference in mean antibody titres between cohorts in March 2006, the mean antibody titre of Cohort(2006) was significantly greater than that of Cohort(2005) in August 2006. No significant differences were observed in seroprevalence. This is one of the few studies to demonstrate the development of acquired resistance in fish against a parasite in an aquaculture environment under natural infection conditions.
Publisher: Wiley
Date: 04-2002
Publisher: Elsevier BV
Date: 04-2006
Publisher: Cambridge University Press (CUP)
Date: 04-2001
DOI: 10.1017/S1357729800058100
Abstract: Many studies with fin fish have demonstrated the potential to use alternative dietary protein sources to fish meal based on growth responses, although these trials mostly neglect to determine if such protein sources affect immune function. This study investigated the effect of fish meal replacement with dehulled lupin meal (LPN) or hydrolysed poultry feather meal (FTH). Atlantic salmon ( Salmo salar L.) parr were supplied isonitrogenous and isoenergetic diets with 40% of the dietary protein provided by LPN or FTH, or 400 g/kg of the dietary protein provided equally by LPN and FTH (MIX). A diet mainly containing fish-meal protein acted as a control (CON). Growth, immune function, blood chemistry and disease resistance were assessed after 56 days. Significant differences ( P 0·05) in weight gain were detected between Atlantic salmon given the CON and FTH diets, whilst those salmon given LPN and MIX did not differ from any other. Productive protein values were significantly lower ( P 0·01) for salmon on FTH compared with those on CON and MIX. Immune function (as assessed by lysozyme, antiprotease, neutrophil oxygen radical production and plasma total immunoglobulin) and blood chemistry (as assessed by plasma total protein and glucose) were not significantly ( P 0·05) affected by any diet. Mortality rates of Atlantic salmon challenged with Vibrio anguillarum were not influenced by diet. These data suggest Atlantic salmon could be supplied diets with the fish meal component reduced to supply approximately 600 g/kg of the total protein, with the remaining 400 g/kg supplied by dehulled lupin meal or a combined dehulled lupin and hydrolysed poultry feather meal without any adverse effects on growth, immune function or blood chemistry.
Publisher: BMJ
Date: 11-07-2019
DOI: 10.1136/BMJSPCARE-2019-001869
Abstract: Patient-relevant measures of functional status are required in chronic obstructive pulmonary disease (COPD) and lung cancer in clinical practice and research. We explored the relationship between the Australia-modified Karnofsky Performance Scale (AKPS) and measures of functional capacity and physical activity in these patient groups. Pooled clinical trial data were analysed to explore the relationship between AKPS and average daily steps (ADS), 6 min walk distance (6MWD), and body mass index, airflow obstruction, dyspnoea and exercise score (COPD group). Receiver operator characteristic curves were produced to compare sensitivity and specificity of cut-offs (no dependency , high dependency ) and area under the curve (AUC). Seven clinical trials included people with COPD (n=79) and lung cancer (n=150). To detect an AKPS of , the optimal ADS cut-points were COPD, 3342 steps (AUC 0.88, 95% CI 0.79 to 0.97, sensitivity 82%, specificity 76%), and lung cancer, 3380 steps (AUC 0.72, 95% CI 0.64 to 0.81, sensitivity 61%, specificity 74%), and for 6MWD (COPD only) 242 m (AUC 0.72, 95% CI 0.63 to 0.81, sensitivity 73%, specificity 34%). An AKPS score is strongly related to ADS in people with COPD and lung cancer. The AKPS may be useful in clinical practice and research to indicate levels of physical activity where ADS and 6 min walk test are not possible. Longitudinal data are needed to confirm these findings.
Publisher: Elsevier BV
Date: 06-2017
DOI: 10.1016/J.MARPOLBUL.2017.03.067
Abstract: Hepatic gene expression and liver histology were examined in sand flathead (Platycephalus bassensis) from six locations in Port Phillip Bay, Victoria, Australia. Four sets of genes including thyroid-related genes (D1, D2, TTR, TRα and TRβ), metal metabolism-related genes (MT, MTF1, TF, Ferritin and FPN1), apoptosis-related genes (Diablo/SMAC1, Diablo/SMAC2 and CYP1A) and an endoplasmic reticulum stress biomarker gene (GRP78) were examined in female flathead using qRT-PCR. TRβ and Diablo/SMAC1 gene expression was significantly up-regulated in fish from all polluted sites compared to those from a reference site. The transcripts of TRα and FPN1 were significantly higher in flathead from Corio Bay, while the hepatic mRNA of TTR and GRP78 were significantly lower in those fish. Positive correlations were observed between Diablo/SMAC1 and CYP1A, D2 and TRβ, TRα and TRβ. This study demonstrates that application of pathway-based biomarker genes and histopathology can provide comprehensive information on the impact of environmental pollutants on fish.
Publisher: Informa UK Limited
Date: 26-11-2018
Publisher: Wiley
Date: 08-05-2020
DOI: 10.1111/JWAS.12692
Publisher: Frontiers Media SA
Date: 24-08-2020
Publisher: Frontiers Media SA
Date: 13-05-2021
DOI: 10.3389/FMARS.2021.676731
Abstract: The fish gut microbiome is impacted by a number of biological and environmental factors including fish feed formulations. Unlike mammals, vertical microbiome transmission is largely absent in fish and thus little is known about how the gut microbiome is initially colonized during hatchery rearing nor the stability throughout growout stages. Here we investigate how various microbial-rich surfaces from the built environment “BE” and feed influence the development of the mucosal microbiome (gill, skin, and digesta) of an economically important marine fish, yellowtail kingfish, Seriola lalandi , over time. For the first experiment, we s led gill and skin microbiomes from 36 fish reared in three tank conditions, and demonstrate that the gill is more influenced by the surrounding environment than the skin. In a second experiment, fish mucous (gill, skin, and digesta), the BE (tank side, water, inlet pipe, airstones, and air diffusers) and feed were s led from indoor reared fish at three ages (43, 137, and 430 dph n = 12 per age). At 430 dph, 20 additional fish were s led from an outdoor ocean net pen. A total of 304 s les were processed for 16S rRNA gene sequencing. Gill and skin alpha ersity increased while gut ersity decreased with age. Diversity was much lower in fish from the ocean net pen compared to indoor fish. The gill and skin are most influenced by the BE early in development, with aeration equipment having more impact in later ages, while the gut “allochthonous” microbiome becomes increasingly differentiated from the environment over time. Feed had a relatively low impact on driving microbial communities. Our findings suggest that S. lalandi mucosal microbiomes are differentially influenced by the BE with a high turnover and rapid succession occurring in the gill and skin while the gut microbiome is more stable. We demonstrate how in idual components of a hatchery system, especially aeration equipment, may contribute directly to microbiome development in a marine fish. In addition, results demonstrate how early life (larval) exposure to biofouling in the rearing environment may influence fish microbiome development which is important for animal health and aquaculture production.
Publisher: Wiley
Date: 12-1999
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.DCI.2013.07.021
Abstract: Amoebic infections in fish are most likely underestimated and sometimes overlooked due to the challenges associated with their diagnosis. Amoebic diseases reported in fish affect either gills or internal organs or may be systemic. Host response ranges from hyperplastic response in gill infections to inflammation (including granuloma formation) in internal organs. This review focuses on the immune response of Atlantic salmon to Neoparamoeba perurans, the causative agent of Amoebic Gill Disease (AGD).
Publisher: Wiley
Date: 08-08-2008
Publisher: Wiley
Date: 16-08-2013
DOI: 10.1111/JFD.12124
Publisher: Wiley
Date: 03-2009
DOI: 10.1111/J.1365-2761.2009.01107.X
Abstract: The chondracanthid copepod, Chondracanthus goldsmidi is an ectoparasite of gills, inner opercula and nasal cavities of cultured striped trumpeter, Latris lineata (Forster). Whilst often present in high numbers (up to 60 parasites per host), little is known about its effect on striped trumpeter. In this study C. goldsmidi was associated with extensive epithelial hyperplasia and necrosis. Pathological changes were most pronounced near the parasite's attachment site, with papilloma-like growths surrounding the entire parasite resulting in deformation of the filament. The number of mucous cells increased near the parasite attachment sites on both the opercula and gills. Mast cells were absent in healthy gills in contrast numerous mast cells were identified in the papilloma-like growths. Immunostaining identified piscidin-positive mast cells in the papilloma-like growths, presenting the first evidence of piscidin in the family Latridae.
Publisher: Inter-Research Science Center
Date: 03-03-2008
DOI: 10.3354/DAO01890
Abstract: In some years, large numbers of Caligus chiastos have been observed on the external surfaces of southern bluefin tuna, particularly on the head and eyes, in some sea cages in Spencer Gulf, Australia. As no epidemiological data were available, we monitored sea lice on tuna (N = 130) in 4 research cages s led at 6 wk intervals during the 2005 farming season. No lice were observed on a s le of 10 wild-caught tuna when the cohort was transferred to cages in early April. By late May more than half the s led tuna (22 of 40) were infected, with up to 42 parasites we also recorded one unidentified Caligus sp. at this time. In early July the number of tuna infected with lice declined to 10% in the final s le in late August none were detected. Prevalence in May was significantly higher than on other dates (p 0.05). The decline in prevalence corresponded with a seasonal fall in temperature, from ca. 17 degrees C in May to 14 degrees C in August. Counts of lice at the peak of infection were associated with the severity of eye damage (Spearman's rank correlation coefficient, r(S,38df) = 0.654, p < 0.001) this may be because lice graze on the cornea or because tuna injure their eyes when flashing (rubbing against objects). Counts at this time were also strongly and inversely correlated with the condition index (r(S,38df) = -0.707, p < 0.001). It appears that tuna become infested with adult sea lice via wild teleosts and elasmobranchs attracted to sea cages.
Publisher: Springer Science and Business Media LLC
Date: 26-09-2015
DOI: 10.1007/S10126-015-9663-7
Abstract: This study examined the feasibility of alginate microcapsules manufactured using a low-impact technology and reagents to protect orally delivered immunogens for use as immunoprophylactics for fish. Physical characteristics and protein release kinetics of the microcapsules were examined at different pH and temperature levels using a microencapsulated model protein, bovine serum albumin (BSA). Impact of the microencapsulation process on contents was determined by analysing change in bioactivity of microencapsulated lysozyme. Feasibility of the method for oral immunoprophylaxis of finfish was assessed using FITC-labelled microcapsules. These were applied to distal intestinal explants of Atlantic salmon (Salmo salar) to investigate uptake ex vivo. Systemic distribution of microcapsules was investigated by oral administration of FITC-labelled microcapsules to Atlantic salmon fry by incorporating into feed. The microcapsules produced were structurally robust and retained surface integrity, with a modal size distribution of 250-750 nm and a tendency to aggregate. Entrapment efficiency of microencapsulation was 51.2 % for BSA and 43.2 % in the case of lysozyme. Microcapsules demonstrated controlled release of protein, which increased with increasing pH or temperature, and the process had no significant negative effect on bioactivity of lysozyme. Uptake of fluorescent-labelled microcapsules was clearly demonstrated by intestinal explants over a 24-h period. Evidence of microcapsules was found in the intestine, spleen, kidney and liver of fry following oral administration. Amenability of the microcapsules to intestinal uptake and distribution reinforced the strong potential for use of this microencapsulation method in oral immunoprophylaxis of finfish using sensitive immunogenic substances.
Publisher: Inter-Research Science Center
Date: 2005
DOI: 10.3354/DAO063175
Abstract: Factors causing amoebic gill disease (AGD), the main disease affecting the salmonid industry in Tasmania, are largely unknown. Managers of 57 sites, from 4 countries, in both the Southern and Northern Hemisphere were questioned regarding the 2000 smolt year-class Atlantic salmon. Questions included site characteristics, fish population characteristics, husbandry and management programs, through to freshwater bathing characteristics. Possible risk factors for AGD outbreaks that were identified in this study using farm managers' opinions were mixed sex stocks (Tasmania), downstream positioning from other salmonid farming sites (pooled), tidal sites (Tasmania), depth of site (pooled), rate of salinity change in halocline and depth of halocline (pooled, Tasmania), phytoplankton blooms (pooled, Tasmania), antifouling paints (Tasmania, overseas) and automated feeding (pooled, overseas). The information from farm managers suggested that freshwater bathing is less effective with smaller bathing cages and lower levels of saturated oxygen in the bathing water. Risk factors could not always be determined due to the complex interactions between the biological and chemical environment, host and pathogenic factors, coupled with low s le numbers.
Publisher: Wiley
Date: 02-2004
DOI: 10.1046/J.1365-2761.2003.00515.X
Abstract: Previous studies have indicated that when Atlantic salmon, Salmo salar L., are exposed to Neoparamoeba sp. the fish produce anti-Neoparamoeba sp. antibodies. It appears unlikely that these antibodies elicit any specific protection against amoebic gill disease (AGD) as fish with demonstrable activities have been affected by AGD. Experiments were conducted on Atlantic salmon cultured throughout Tasmania to assess the natural production of antibodies towards Neoparamoeba sp. Fish were s led from areas where AGD was prevalent and from areas where there had been no reported cases. An enzyme-linked immunosorbent assay (ELISA) was used to measure anti-Neoparamoeba sp. antibody activities in serum. All fish from sea water had antibody activities greater than the negative control fish, including fish from areas with no reported cases of AGD. Time trial s les indicated that time after transfer to sea water did not appear to be a significant (P > 0.05) factor in antibody activity, however location was (P < 0.05). There was no agreement (corrected kappa value, 0.16) between the ELISA result and the isolation of Neoparamoeba sp. from the gills of the same fish. The results suggest that Atlantic salmon in seawater culture in Tasmania produce anti-Neoparamoeba sp. antibodies regardless of infection history, suggesting the presence of Neoparamoeba sp. in the environment.
Publisher: American Society for Microbiology
Date: 02-06-2020
DOI: 10.1128/AEM.00411-20
Abstract: Atlantic salmon, Salmo salar , is the most farmed marine fish worldwide, with an annual production of 2,248 million metric tons in 2016. Salmon hatcheries are increasingly changing from flowthrough toward recirculating aquaculture system (RAS) design to accommodate more control over production along with improved environmental sustainability due to lower impacts on water consumption. To date, microbiome studies of hatcheries have focused either on the fish mucosal microbiota or on the built environment microbiota but have not combined the two to understand their interactions. Our study evaluates how the water and tank biofilm microbiota influences the fish microbiota across three mucosal environments (gill, skin, and digesta). Results from this study highlight how the built environment is a unique source of microbes to colonize fish mucus and, furthermore, how this can influence fish health. Further studies can use this knowledge to engineer built environments to modulate fish microbiota for beneficial phenotypes.
Publisher: Springer Science and Business Media LLC
Date: 02-07-2019
Publisher: Elsevier BV
Date: 11-2006
DOI: 10.1016/J.VETIMM.2006.08.002
Abstract: The characterisation of selected immune response genes during amoebic gill disease (AGD) in Atlantic salmon, Salmo salar L., was performed using semi-quantitative RT-PCR, quantitative real-time RT-PCR (qRT-PCR), and in situ hybridisation (ISH). The immune response genes of interest were interleukin-1beta (IL-1beta), inducible nitric oxide synthase (iNOS), serum amyloid A (SAA), and serum amyloid P-like pentraxin (SAP). Atlantic salmon were inoculated with the ectoparasite Neoparamoeba sp., the causative agent of AGD, and gill, liver and anterior kidney tissue s led at 0, 7 and 14 d post-inoculation (p.i.). Semi-quantitative RT-PCR was performed on the tissue s les to identify up/down-regulated mRNA expression relative to uninfected control fish and normalised to the housekeeping gene, beta-actin. Interleukin-1beta (IL-1beta) was the only immune response gene of those investigated whose mRNA was differentially regulated in any of the tissues and was found to be up-regulated in the gills by semi-quantitative RT-PCR. Increased gill IL-1beta mRNA expression was then accurately quantitated and confirmed using probe-based qRT-PCR. The cellular localisation of the IL-1beta mRNA expression in the gills of uninfected and infected fish was then determined by ISH using an IL-1beta-specific biotinylated cRNA probe. Expression of IL-1beta mRNA was localised to filament and lamellar epithelium pavement cells in gills of uninfected and infected Atlantic salmon. These data implicate the involvement of IL-1beta at the site of infection, the gills, of Atlantic salmon during AGD. This work supports previous studies that suggest IL-1beta is important in the regulation of the fish immune response to parasitic infection but additionally shows the cellular localisation of fish IL-1beta mRNA expression during infection.
Publisher: Elsevier BV
Date: 1997
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Barbara Nowak.