ORCID Profile
0000-0002-0165-3797
Current Organisation
Murdoch University
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Publisher: Wiley
Date: 09-2016
DOI: 10.1111/PIM.12350
Abstract: Cryptosporidium is a major cause of moderate-to-severe diarrhoea in humans worldwide, second only to rotavirus. Due to the wide host range and environmental persistence of this parasite, cryptosporidiosis can be zoonotic and associated with foodborne and waterborne outbreaks. Currently, 31 species are recognized as valid, and of these, Cryptosporidium hominis and Cryptosporidium parvum are responsible for the majority of infections in humans. The immune status of the host, both innate and adaptive immunity, has a major impact on the severity of the disease and its prognosis. Immunocompetent in iduals typically experience self-limiting diarrhoea and transient gastroenteritis lasting up to 2 weeks and recover without treatment, suggesting an efficient host antiparasite immune response. Immunocompromised in iduals can suffer from intractable diarrhoea, which can be fatal. Effective drug treatments and vaccines are not yet available. As a result of this, the close cooperation and interaction between veterinarians, health physicians, environmental managers and public health operators is essential to properly control this disease. This review focuses on a One Health approach to prophylaxis, including the importance of understanding transmission routes for zoonotic Cryptosporidium species, improved sanitation and better risk management, improved detection, diagnosis and treatment and the prospect of an effective anticryptosporidial vaccine.
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.SCITOTENV.2018.07.024
Abstract: Wastewater recycling is an increasingly popular option in worldwide to reduce pressure on water supplies due to population growth and climate change. Cryptosporidium spp. are among the most common parasites found in wastewater and understanding the prevalence of human-infectious species is essential for accurate quantitative microbial risk assessment (QMRA) and cost-effective management of wastewater. The present study conducted next generation sequencing (NGS) to determine the prevalence and ersity of Cryptosporidium species in 730 raw influent s les from 25 Australian wastewater treatment plants (WWTPs) across three states: New South Wales (NSW), Queensland (QLD) and Western Australia (WA), between 2014 and 2015. All s les were screened for the presence of Cryptosporidium at the 18S rRNA (18S) locus using quantitative PCR (qPCR), oocyst numbers were determined directly from the qPCR data using DNA standards calibrated by droplet digital PCR, and positives were characterized using NGS of 18S licons. Positives were also screened using C. parvum and C. hominis specific qPCRs. The overall Cryptosporidium prevalence was 11.4% (83/730): 14.3% (3/21) in NSW 10.8% (51/470) in QLD and 12.1% (29/239) in WA. A total of 17 Cryptosporidium species and six genotypes were detected by NGS. In NSW, C. hominis and Cryptosporidium rat genotype III were the most prevalent species (9.5% each). In QLD, C. galli, C. muris and C. parvum were the three most prevalent species (7.7%, 5.7%, and 4.5%, respectively), while in WA, C. meleagridis was the most prevalent species (6.3%). The oocyst load/Litre ranged from 70 to 18,055 oocysts/L (overall mean of 3426 oocysts/L: 4746 oocysts/L in NSW 3578 oocysts/L in QLD and 3292 oocysts/L in WA). NGS-based profiling demonstrated that Cryptosporidium is prevalent in the raw influent across Australia and revealed a large ersity of Cryptosporidium species and genotypes, which indicates the potential contribution of livestock, wildlife and birds to wastewater contamination.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 04-2016
Publisher: Wiley
Date: 17-01-2021
DOI: 10.1111/ZPH.12806
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.WATRES.2018.02.005
Abstract: As part of long-term monitoring of Cryptosporidium in water catchments serving Western Australia, New South Wales (Sydney) and Queensland, Australia, we characterised Cryptosporidium in a total of 5774 faecal s les from 17 known host species and 7 unknown bird s les, in 11 water catchment areas over a period of 30 months (July 2013 to December 2015). All s les were initially screened for Cryptosporidium spp. at the 18S rRNA locus using a quantitative PCR (qPCR). Positives s les were then typed by sequence analysis of an 825 bp fragment of the 18S gene and subtyped at the glycoprotein 60 (gp60) locus (832 bp). The overall prevalence of Cryptosporidium across the various hosts s led was 18.3% (1054/5774 95% CI, 17.3-19.3). Of these, 873 s les produced clean Sanger sequencing chromatograms, and the remaining 181 s les, which initially produced chromatograms suggesting the presence of multiple different sequences, were re-analysed by Next- Generation Sequencing (NGS) to resolve the presence of Cryptosporidium and the species composition of potential mixed infections. The overall prevalence of confirmed mixed infection was 1.7% (98/5774), and in the remaining 83 s les, NGS only detected one species of Cryptosporidium. Of the 17 Cryptosporidium species and four genotypes detected (Sanger sequencing combined with NGS), 13 are capable of infecting humans C. parvum, C. hominis, C. ubiquitum, C. cuniculus, C. meleagridis, C. canis, C. felis, C. muris, C. suis, C. scrofarum, C. bovis, C. erinacei and C. fayeri. Oocyst numbers per gram of faeces (g
Publisher: Springer Science and Business Media LLC
Date: 13-01-2016
DOI: 10.1007/S00436-016-4901-0
Abstract: A molecular epidemiological survey of Cryptosporidium from water buffalo (Bubalus bubalis) in the Northern Territory in Australia was conducted. Fecal s les were collected from adult farmed (n = 50) and wild buffalo (n = 50) and screened using an 18S quantitative PCR (qPCR). Positives were typed by sequence analysis of 18S nested PCR products. The qPCR prevalence of Cryptosporidium species in farmed and wild buffalo was 30 and 12 %, respectively. Sequence analysis identified two species: C. parvum and C. bovis, with C. parvum accounting for ~80 % of positives typed from the farmed buffalo fecal s les compared to 50 % for wild buffalo. Subtyping at the 60 kDa glycoprotein (gp60) locus identified C. parvum subtypes IIdA19G1 (n = 4) and IIdA15G1 (n = 1) in the farmed buffalo and IIaA18G3R1 (n = 2) in the wild buffalo. The presence of C. parvum, which commonly infects humans, suggests that water buffaloes may contribute to contamination of rivers and waterways with human infectious Cryptosporidium oocysts, and further research on the epidemiology of Cryptosporidium in buffalo populations in Australia is required.
Publisher: Public Library of Science (PLoS)
Date: 14-12-2016
Publisher: Springer Science and Business Media LLC
Date: 21-11-2020
DOI: 10.1007/S00436-019-06547-9
Abstract: The Bellinger River snapping turtle (Myuchelys georgesi) is endemic to Australia and is confined to a highly restricted distribution in the Bellinger River in New South Wales. Routine veterinary health examinations of 17 healthy turtles were undertaken, along with the collection and analysis of blood s les, during conservation efforts to save the species following a catastrophic population decline. Microscopy analysis of blood films detected Haemoproteidae parasites that morphologically resembled Haemocystidium chelodinae inside turtle erythrocytes. Of the 17 turtles examined, 16 were positive for infection with H. chelodinae by both light microscopy and PCR. DNA sequencing of a partial fragment of the mitochondrial cytochrome b (cytb) gene and phylogenetic analysis identified two different H. chelodinae-like genotypes. The phylogenetic relationship of H. chelodinae-like to other Haemoproteidae species based on cytb sequences grouped H. chelodinae-like into the reptile clade, but revealed the Haemocystidium genus to be paraphyletic as the clade also contained Haemoproteus, thus supporting a re-naming of Haemoproteus species from reptiles to Haemocystidium species. This study reports for the first time the genetic characterisation of H. chelodinae-like organisms isolated from a new Testudine host species, the Bellinger River snapping turtle. As evidence grows, further research will be necessary to understand the mode of transmission and to investigate whether these parasites are pathogenic to their hosts.
Publisher: Cambridge University Press (CUP)
Date: 09-05-2017
DOI: 10.1017/S0031182017000439
Abstract: Little is known about the genetic ersity of the protozoan parasite, Giardia duodenalis, infecting humans in Queensland, Australia. The present study typed 88 microscopically Giardia -positive isolates using assemblage-specific primers at the triose phosphate isomerase ( tpi ) gene and sequenced a subset of isolates at the glutamate dehydrogenase ( gdh ) gene ( n = 30) and tpi locus ( n = 27). Using the tpi -assemblage specific primers, G. duodenalis assemblage A and assemblage B were detected in 50% (44/88) and 38·6% (34/88) of s les, respectively. Mixed infections with assemblages A and B were identified in 4·5% (4/88) and assemblage E was identified in 6·8% (6/88) of s les. Sequence analysis at the gdh and tpi loci also confirmed the presence of assemblage E in these isolates. Cyst numbers per gram of feces (g −1 ) were determined using quantitative polymerase chain reaction and of the isolates that were typed as assemblage E, cyst numbers ranged 13·8–68·3 × 10 6 cysts g −1 . This is the first report of assemblage E in humans in Australia, indicating that in certain settings, this assemblage may be zoonotic.
Publisher: Springer Science and Business Media LLC
Date: 20-03-2018
Publisher: Elsevier BV
Date: 08-2021
DOI: 10.1016/J.MEEGID.2021.104859
Abstract: Cryptosporidium is an important protozoan parasite and due to its resistance to chlorine is a major cause of swimming pool-associated gastroenteritis outbreaks. The present study combined contact tracing and molecular techniques to analyse cryptosporidiosis cases and outbreaks in Western Australia in 2019 and 2020. In the 2019 outbreak, subtyping at the 60 kDa glycoprotein (gp60) gene identified 89.0% (16/18) of s les were caused by the C. hominis IdA15G1 subtype. Amplicon next generation sequencing (NGS) at the gp60 locus identified five C. hominis IdA15G1 subtype s les that also had C. hominis IdA14 subtype DNA, while multi locus sequence typing (MLST) analysis on a subset (n = 14) of C. hominis s les identified three IdA15G1 s les with a 6 bp insertion at the end of the trinucleotide repeat region of the cp47 gene. In 2020, 88.0% (73/83) of s les typed were caused by the relatively rare C. hominis subtype IbA12G3. Four mixed infections were observed by NGS with three IdA15G1/ IdA14 mixtures and one C. parvum IIaA18G3R1 s le mixed with IIaA16G3R1. No genetic ersity using MLST was detected. Epidemiological and molecular data indicates that the outbreaks in 2019 and 2020 were each potentially from swimming pool point sources and a new C. hominis subtype IbA12G3 is emerging in Australia. The findings of the present study are important for understanding the introduction and transmission of rare Cryptosporidium subtypes to vulnerable populations.
Publisher: Springer Science and Business Media LLC
Date: 24-04-2019
Publisher: MDPI AG
Date: 30-12-2022
DOI: 10.3390/PATHOGENS12010061
Abstract: Cryptosporidium parvum is a significant cause of watery diarrhoea in humans and other animals worldwide. Although hundreds of novel drugs have been evaluated, no effective specific chemotherapeutic intervention for C. parvum has been reported. There has been much recent interest in evaluating plant-derived products in the fight against gastrointestinal parasites, including C. parvum. This study aimed to identify extracts from 13 different plant species that provide evidence for inhibiting the growth of C. parvum in vitro. Efficacy against C. parvum was detected and quantified using quantitative PCR and immunofluorescence assays. All plant extracts tested against C. parvum showed varying inhibition activities in vitro, and none of them produced a cytotoxic effect on HCT-8 cells at concentrations up to 500 µg/mL. Four plant species with the strongest evidence of activity against C. parvum were Curcuma longa, Piper nigrum, Embelia ribes, and Nigella sativa, all with dose-dependent efficacy. To the authors' knowledge, this is the first time that these plant extracts have proven to be experimentally efficacious against C. parvum. These results support further exploration of these plants and their compounds as possible treatments for Cryptosporidium infections.
Publisher: Elsevier
Date: 2019
DOI: 10.1016/BS.APAR.2019.07.002
Abstract: A total of eight Giardia species are accepted. These include: Giardia duodenalis (syn. Giardia intestinalis and Giardia lamblia), which infects humans and animals, Giardia agilis, Giardia ardeae, Giardia psittaci, Giardia muris, Giardia microti, Giardia peramelis and G. cricetidarum, which infect non-human hosts including hibians, birds, rodents and marsupials. Giardia duodenalis is a species complex consisting of eight assemblages (A-H), with assemblages A and B the dominant assemblages in humans. Molecular studies to date on the zoonotic potential of Giardia in animals are problematic and are h ered by lack of concordance between loci. Livestock (cattle, sheep, goats and pigs) are predominantly infected with G. duodenalis assemblage E, which has recently been shown to be zoonotic, followed by assemblage A. In cats and dogs, assemblages A, B, C, D and F are commonly reported but relatively few studies have conducted molecular typing of humans and their pets and the results are contradictory with some studies support zoonotic transmission but the majority of studies suggesting separate transmission cycles. Giardia also infects a broad range of wildlife hosts and although much less well studied, host-adapted species as well as G. duodenalis assemblages (A-H) have been identified. Fish and other aquatic wildlife represent a source of infection for humans with Giardia via water contamination and/or consumption of undercooked fish and interestingly, assemblage B and A predominated in the two molecular studies conducted to date. Our current knowledge of the transmission dynamics of Giardia is still poor and the development of more discriminatory typing tools such as whole genome sequencing (WGS) of Giardia isolates is therefore essential.
Publisher: Springer Science and Business Media LLC
Date: 30-10-2019
DOI: 10.1186/S13071-019-3759-2
Abstract: Apicomplexan parasites of the genus Cryptosporidium infect a wide range of animal species as well as humans. Cryptosporidium spp. can cause life threatening diarrhea especially in young animals, children, immunocompromised patients and malnourished in iduals. Asymptomatic cryptosporidial infections in animals can also occur, making these animals potential reservoirs of infection. In the present study, a molecular survey of Cryptosporidium spp. in ruminants that were slaughtered for human consumption in Yazd Province, located in central Iran was conducted. Faeces were collected per-rectum from 484 animals including 192 cattle, 192 sheep and 100 goats. DNA was extracted from all s les and screened for Cryptosporidium by PCR lification of the 18S rRNA gene. Positives were Sanger sequenced and further subtyped by sequence analysis of the 60 kDa glycoprotein ( gp60 ) locus. In total, Cryptosporidium spp. were detected in 22 animals: C. andersoni and C. bovis in seven and two cattle faecal s les, respectively, C. ubiquitum in five sheep, and C. xiaoi in six sheep and two goat s les, respectively. To our knowledge, this study provides for the first time, molecular information concerning Cryptosporidium species infecting goats in Iran, and is also the first report of C. ubiquitum and C. xiaoi from ruminants in Iran. The presence of potentially zoonotic species of Cryptosporidium in ruminants in this region may suggest that livestock could potentially contribute to human cryptosporidiosis, in particular among farmers and slaughterhouse workers, in the area. Further molecular studies on local human populations are required to more accurately understand the epidemiology and transmission dynamics of Cryptosporidium spp. in this region.
Publisher: Elsevier BV
Date: 05-2020
Publisher: MDPI AG
Date: 19-11-2021
DOI: 10.3390/ANI11113307
Abstract: The enteric parasite, Cryptosporidium is a major cause of diarrhoeal illness in humans and animals worldwide. No effective therapeutics or vaccines are available and therefore control is dependent on understanding transmission dynamics. The development of molecular detection and typing tools has resulted in the identification of a large number of cryptic species and genotypes and facilitated our understanding of their potential for zoonotic transmission. Of the 44 recognised Cryptosporidium species and genotypes, 19 species, and four genotypes have been reported in humans with C. hominis, C. parvum, C. meleagridis, C. canis and C. felis being the most prevalent. The development of typing tools that are still lacking some zoonotic species and genotypes and more extensive molecular epidemiological studies in countries where the potential for transmission is highest are required to further our understanding of this important zoonotic pathogen. Similarly, whole-genome sequencing (WGS) and licon next-generation sequencing (NGS) are important for more accurately tracking transmission and understanding the mechanisms behind host specificity.
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.MEEGID.2019.104021
Abstract: Giardia duodenalis is one of the most common intestinal parasites in humans as well as livestock and wildlife. It is of both public and veterinary health importance in developing nations. A molecular survey of Giardia duodenalis assemblages in ruminants from Yazd Province, Iran was conducted on 484 animal faecal s les collected per rectum from slaughtered ruminants including 192 cattle, 192 sheep and 100 goats from June to November 2017. Species-specific and assemblage-specific PCRs for assemblages A, B and E at the triose phosphate isomerase (tpi) gene were performed, and s les positive for Giardia were confirmed by sequencing. In total, 25 (5.16%) of examined faecal s les including eight cattle (4.2%), twelve sheep (6.2%) and five goats (5%) were infected with G. duodenalis. Assemblage-specific PCR detected G. duodenalis assemblage E in seven faecal s les (six in sheep and one in a goat). Assemblages A and B were not detected. This study provides the first insight into Giardia infection in slaughtered livestock in Iran. Although the prevalence of infection with Giardia in this hot-arid area of Iran was low, educating people about direct contact with livestock such as farmers and abattoirs workers about this zoonotic infection is important.
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.VETPAR.2017.08.014
Abstract: The morphological, biological, and molecular characterisation of a new Cryptosporidium species from the guinea pig (Cavia porcellus) are described, and the species name Cryptosporidium homai n. sp. is proposed. Histological analysis conducted on a post-mortem s le from a guinea pig euthanised due to respiratory distress, identified developmental stages of C. homai n. sp. (trophozoites and meronts) along the intestinal epithelium. Molecular analysis at 18S rRNA (18S), actin and hsp70 loci was then conducted on faeces from an additional 7 guinea pigs positive for C. homai n. sp. At the 18S, actin and hsp70 loci, C. homai n. sp. exhibited genetic distances ranging from 3.1% to 14.3%, 14.4% to 24.5%, and 6.6% to 20.9% from other Cryptosporidium spp., respectively. At the 18S locus, C. homai n. sp. shared 99.1% similarity with a previously described Cryptosporidium genotype in guinea pigs from Brazil and it is likely that they are the same species, however this cannot be confirmed as actin and hsp70 sequences from the Brazilian guinea pig genotype are not available. Phylogenetic analysis of concatenated 18S, actin and hsp70 sequences showed that C. homai n. sp. exhibited 9.1% to 17.3% genetic distance from all other Cryptosporidium spp. This clearly supports the validity of C. homai n. sp. as a separate species.
Publisher: Elsevier BV
Date: 09-2019
DOI: 10.1016/J.MEEGID.2019.05.018
Abstract: Cryptosporidium species are a major cause of diarrhoea worldwide. In the present study, a retrospective analysis of 109 microscopically Cryptosporidium-positive faecal specimens from Western Australian patients, collected between 2015 and 2018 was conducted. Sequence analysis of the 18S rRNA and the 60 kDa glycoprotein (gp60) gene loci identified four Cryptosporidium species: C. hominis (86.2%, 94/109), C. parvum (11.0%, 12/109), C. meleagridis (1.8%, 2/109) and C. viatorum (0.9%, 1/109). Subtyping at the gp60 locus identified a total of 11 subtypes including the emergence of the previously rare C. hominis IfA12G1R5 subtype in 2017 as the dominant subtype (46.7%, 21/45). This subtype has also recently emerged as the dominant subtype in the United States but the reasons for its emergence are unknown. This is also the first report of C. viatorum in humans in Australia and a novel subtype (XVaA3g) was identified in the one positive patient.
Publisher: MDPI AG
Date: 16-12-2020
DOI: 10.3390/MICROORGANISMS8122014
Abstract: Current knowledge of Cryptosporidium species/genotypes in marine fish is limited. Following phylogenetic analysis at the 18S rDNA locus, a recent study identified six new genotypes of Cryptosporidium colonizing edible fish found in European seas. Of these, five grouped in a clade together (#Cryptofish 1–5) and one grouped separately (#Cryptofish 7). In the present study, after phylogenetic analyses of #Cryptofish1, #Cryptofish2, #Cryptofish4, #Cryptofish5 and #Cryptofish7 at the actin locus, the presence of two major clades was confirmed. In addition, when possible, longer 18S licons were generated. In conclusion, the small genetic distances between these genotypes designated as a novel marine genotype I (#Cryptofish 1-5) suggest that they may be genetic variants of the same species, while the designated novel marine genotype 2 (#Cryptofish 7) is clearly representative of a separate species.
Publisher: MDPI AG
Date: 11-05-2020
DOI: 10.3390/MICROORGANISMS8050715
Abstract: Cryptosporidium is a major cause of severe diarrhea-related disease in children in developing countries, but currently no vaccine or effective treatment exists for those who are most at risk of serious illness. This is partly due to the lack of in vitro culturing methods that are able to support the entire Cryptosporidium life cycle, which has led to research in Cryptosporidium biology lagging behind other protozoan parasites. In vivo models such as gnotobiotic piglets are complex, and standard in vitro culturing methods in transformed cell lines, such as HCT-8 cells, have not been able to fully support fertilization occurring in vitro. Additionally, the Cryptosporidium life cycle has also been reported to occur in the absence of host cells. Recently developed bioengineered intestinal models, however, have shown more promising results and are able to reproduce a whole cycle of infectivity in one model system. This review evaluates the recent advances in Cryptosporidium culturing techniques and proposes future directions for research that may build upon these successes.
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.IJPARA.2017.03.003
Abstract: The extent of within-host genetic ersity of parasites has implications for our understanding of the epidemiology, disease severity and evolution of parasite virulence. As with many other species, our understanding of the within-host ersity of the enteric parasite Cryptosporidium is changing. The present study compared Sanger and Next Generation Sequencing of glycoprotein 60 (gp60) licons from Cryptosporidium hominis (n=11), Cryptosporidium parvum (n=22) and Cryptosporidium cuniculus (n=8) DNA s les from Australia and China. Sanger sequencing identified only one gp60 subtype in each DNA s le: one C. hominis subtype (IbA10G2) (n=11), four C. parvum subtypes belonging to IIa (n=3) and IId (n=19) and one C. cuniculus subtype (VbA23) (n=8). Next Generation Sequencing identified the same subtypes initially identified by Sanger sequencing, but also identified additional gp60 subtypes in C. parvum and C. cuniculus but not in C. hominis, DNA s les. The number of C. parvum and C. cuniculus subtypes identified by Next Generation Sequencing within in idual DNA s les ranged from two to four, and both C. parvum IIa and IId subtype families were identified within the one host in two s les. The finding of the present study has important implications for Cryptosporidium transmission tracking as well as vaccine and drug studies.
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.SCITOTENV.2019.03.278
Abstract: Recycled wastewater can carry human-infectious microbial pathogens and therefore wastewater treatment strategies must effectively eliminate pathogens before recycled wastewater is used to supplement drinking and agricultural water supplies. This study characterised the bacterial composition of four wastewater treatment plants (WWTPs) (three waste stabilisation ponds and one oxidation ditch WWTP using activated sludge treatment) in Western Australia. The hypervariable region 4 (V4) of the bacterial 16S rRNA (16S) gene was sequenced using next-generation sequencing (NGS) on the Illumina MiSeq platform. Sequences were pre-processed in USEARCH v10.0 and denoised into zero-radius taxonomic units (ZOTUs) with UNOISE3. Taxonomy was assigned to the ZOTUs using QIIME 2 and the Greengenes database and cross-checked with the NCBI nr/nt database. Bacterial composition of all WWTPs and treatment stages (influent, intermediate and effluent) were dominated by Proteobacteria (29.0-87.4%), particularly Betaproteobacteria (9.0-53.5%) and Gammaproteobacteria (8.6-34.6%). Nitrifying bacteria (Nitrospira spp.) were found only in the intermediate and effluent of the oxidation ditch WWTP, and denitrifying and floc-forming bacteria were detected in all WWTPs, particularly from the families Comamonadaceae and Rhodocyclales. Twelve pathogens were assigned taxonomy by the Greengenes database, but comparison of sequences from genera and families known to contain pathogens to the NCBI nr/nt database showed that only three pathogens (Arcobacter venerupis, Laribacter hongkongensis and Neisseria canis) could be identified in the dataset at the V4 region. Importantly, Enterobacteriaceae genera could not be differentiated. Family level taxa assigned by Greengenes database agreed with NCBI nr/nt in most cases, however, BLAST analyses revealed erroneous taxa in Greengenes database. This study highlights the importance of validating taxonomy of NGS sequences with databases such as NCBI nr/nt, and recommends including the V3 region of 16S in future short licon NGS studies that aim to identify bacterial enteric pathogens, as this will improve taxonomic resolution of most, but not all, Enterobacteriaceae species.
Publisher: Springer Science and Business Media LLC
Date: 26-06-2018
DOI: 10.1515/AP-2018-0049
Abstract: Cryptosporidium is an important enteric parasite that can contribute large numbers of infectious oocysts to drinking water catchments. As a result of its resistance to disinfectants including chlorine, it has been responsible for numerous waterborne outbreaks of gastroenteritis. Wildlife and livestock play an important role in the transmission of Cryptosporidium in the environment. Studies conducted outside Australia have indicated that camels may also play a role in the transmission of zoonotic species of Cryptosporidium . Despite Australia being home to the world’s largest camel herd, nothing is known about the prevalence and species of Cryptosporidium infecting camels in this country. In the present study, C. parvum was identified by PCR lification and sequencing of a formalin-fixed intestinal tissue specimen from a one-week old dromedary camel ( Camelus dromedarius ). Subtyping analysis at the glycoprotein 60 ( gp60 ) locus identified C. parvum subtype IIaA17G2R1, which is a common zoonotic subtype reported in humans and animals worldwide. Histopathological findings also confirmed the presence of large numbers of variably-sized (1–3 µm in diameter) circular basophilic protozoa – consistent with Cryptosporidium spp.– adherent to the mucosal surface and occasionally free within the lumen. Further analysis of the prevalence and species of Cryptosporidium in camel populations across Australia are essential to better understand their potential for contamination of drinking water catchments.
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1016/J.MEEGID.2017.08.033
Abstract: Cryptosporidiosis is a protozoan parasitic disease which affects human and animals worldwide. In adult immunocompetent in iduals, cryptosporidiosis usually results in acute and self-limited diarrhoea however, it can cause life threatening diarrhoea in children and immunocompromised in iduals. In the present study, we compared the prevalence of Cryptosporidium species and gp60 subtypes amongst paediatric oncology patients with diarrhoea (n=160) from King Hussein Medical Centre for Cancer in Jordan, and non-oncology paediatric patients with diarrhoea (n=137) from Al-Mafraq paediatric hospital. Microscopy results using modified acid fast staining identified a significantly (p≤0.05) higher prevalence of Cryptosporidium in paediatric oncology patients with diarrhoea (14.4% - 23/160), compared to non-oncology paediatric patients with diarrhoea only (5.1% - 7/137). With the exception of one s le, all microscopy-positive s les (n=29) and an additional 3/30 microscopy-negative controls were typed to species and subtype level at the 18S and gp60 loci, respectively. All Cryptosporidium positives were typed as C. parvum. Of the 22 typed Cryptosporidium positives from the paediatric oncology patients, 21 were subtyped as IIaA17G2R1 and one as IIaA16G2R1 C. parvum subtypes. The 7 typed positives from the paediatric patients from Al-Mafraq hospital were subtyped as IIaA17G2R1 (n=5) and IIaA16G2R1 (n=2). The 3 additional positives from the 30 microscopy negative control s les were subtyped as IIaA17G2R1. The high prevalence of the IIaA17G2R1 subtype, particularly amongst oncology patients, suggests that an outbreak of cryptosporidiosis may have been occurring in oncology patients during the collection period (April to December, 2016). New therapies for cryptosporidiosis in immunocompromised patients are urgently required.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.WATRES.2019.04.041
Abstract: While some microbial eukaryotes can improve effluent quality in wastewater treatment plants (WWTPs), eukaryotic waterborne pathogens are a threat to public health. This study aimed to identify Eukarya, particularly faecal pathogens including Cryptosporidium, in different treatment stages (influent, intermediate and effluent) from four WWTPs in Western Australia (WA). Three WWTPs that utilise stabilisation ponds and one WWTP that uses activated sludge (oxidation ditch) treatment technologies were s led. Eukaryotic 18S rRNA (18S) was targeted in the wastewater s les (n = 26) for next-generation sequencing (NGS), and a mammalian-blocking primer was used to reduce the lification of mammalian DNA. Overall, bioinformatics analyses revealed 49 eukaryotic phyla in WWTP s les, and three of these phyla contained human intestinal parasites, which were primarily detected in the influent. These human intestinal parasites either had a low percent sequence composition or were not detected in the intermediate and effluent stages and included the amoebozoans Endolimax sp., Entamoeba sp. and Iodamoeba sp., the human pinworm Enterobius vermicularis (Nematoda), and Blastocystis sp. subtypes (Sarcomastigophora). Six Blastocystis subtypes and four Entamoeba species were identified by eukaryotic 18S NGS, however, Cryptosporidium sp. and Giardia sp. were not detected. Real-time polymerase chain reaction (PCR) also failed to detect Giardia, but Cryptosporidium-specific NGS detected Cryptosporidium in all WWTPs, and a total of nine species were identified, including five zoonotic pathogens. Although eukaryotic 18S NGS was able to identify some faecal pathogens, this study has demonstrated that more specific NGS approaches for pathogen detection are more sensitive and should be applied to future wastewater pathogen assessments.
Publisher: Elsevier BV
Date: 10-2020
No related grants have been discovered for Alireza Zahedi.