ORCID Profile
0000-0002-4758-1506
Current Organisation
University of South Australia
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Population, Ecological and Evolutionary Genetics | Conservation and Biodiversity | Biogeography and Phylogeography | Evolutionary Biology
Expanding Knowledge in the Environmental Sciences | Expanding Knowledge in the Biological Sciences | Flora, Fauna and Biodiversity at Regional or Larger Scales |
Publisher: Wiley
Date: 17-11-2009
DOI: 10.1111/J.1365-2915.2009.00834.X
Abstract: In Cairns, Australia, the impacts on Aedes aegypti L. (Diptera: Culicidae) populations of two types of 'lure & kill' (L&K) lethal ovitraps (LOs), the standard lethal ovitrap (SLO) and the biodegradable lethal ovitrap (BLO) were measured during three mass-trapping interventions. To assess the efficacy of the SLO, two interventions (one dry season and one wet season) were conducted in three discrete areas, each lasting 4 weeks, with the following treatments: (i) SLOs (>200 traps, approximately 4 remise), BG-sentinel traps (BGSs approximately 15, 1 remise) and larval control (container reduction and methoprene treatment) and (ii) larval control alone, and (iii) untreated control. Female Ae. aegypti populations were monitored for 4 weeks pre- and post-treatment in all three areas using BGSs and sticky ovitraps (SOs) or non-lethal regular ovitraps (ROs). In the dry season, 206 SLOs and 15 BGSs set at 54 and 15 houses, respectively, caught and killed an estimated 419 and 73 female Ae. aegypti, respectively. No significant decrease in collection size of female Ae. aegypti could be attributed to the treatments. In the wet season, 243 SLOs and 15 BGSs killed approximately 993 and 119 female Ae. aegypti, respectively. The mean number of female Ae. aegypti collected after 4 weeks with SOs and BGSs was significantly less than the control (LSD post-hoc test). The third mass-trapping intervention was conducted using the BLO during the wet season in Cairns. For this trial, three treatment areas were each provided with BLOs (>500, approximately 4 remise) plus larval control, and an untreated control area was designated. Adult female Ae. aegypti were collected for 4 weeks pre- and post-treatment using 15 BGSs and 20 SOs. During this period, 53.2% of BLOs contained a total of 6654 Ae. aegypti eggs. Over the intervention period, collections of Ae. aegypti in the treatment areas were significantly less than in the control area for BGSs but not SOs. An influx of relatively large numbers of young females may have confounded the measurement of changes in populations of older females in these studies. This is an important issue, with implications for assessing delayed action control measures, such as LOs and parasites athogens that aim to change mosquito age structure. Finally, the high public acceptability of SLOs and BLOs, coupled with significant impacts on female Ae. aegypti populations in two of the three interventions reported here, suggest that mass trapping with SLOs and BLOs can be an effective component of a dengue control strategy.
Publisher: Public Library of Science (PLoS)
Date: 16-11-2021
DOI: 10.1371/JOURNAL.PNTD.0009963
Abstract: Australia is theoretically at risk of epidemic chikungunya virus (CHIKV) activity as the principal vectors are present on the mainland Aedes aegypti ) and some islands of the Torres Strait ( Ae . aegypti and Ae . albopictus ). Both vectors are highly invasive and adapted to urban environments with a capacity to expand their distributions into south-east Queensland and other states in Australia. We sought to estimate the epidemic potential of CHIKV, which is not currently endemic in Australia, by considering exclusively transmission by the established vector in Australia, Ae . aegypti , due to the historical relevance and anthropophilic nature of the vector. We estimated the historical (1995–2019) epidemic potential of CHIKV in eleven Australian locations, including the Torres Strait, using a basic reproduction number equation. We found that the main urban centres of Northern Australia could sustain an epidemic of CHIKV. We then estimated future trends in epidemic potential for the main centres for the years 2020 to 2029. We also conducted uncertainty and sensitivity analyses on the variables comprising the basic reproduction number and found high sensitivity to mosquito population size, human population size, impact of vector control and human infectious period. By estimating the epidemic potential for CHIKV transmission on mainland Australia and the Torres Strait, we identified key areas of focus for controlling vector populations and reducing human exposure. As the epidemic potential of the virus is estimated to rise towards 2029, a greater focus on control and prevention measures should be implemented in at-risk locations.
Publisher: Informa UK Limited
Date: 02-01-2015
Publisher: Informa UK Limited
Date: 02-01-2015
Publisher: Wiley
Date: 08-01-2019
DOI: 10.1111/TRF.15095
Abstract: Zika virus (ZIKV) is transfusion-transmissible. In Australia the primary vector, Aedes aegypti, is established in the north-east, such that local transmission is possible following importation of an index case, which has the potential to impact on blood transfusion safety and public health. We estimated the basic reproduction number (R Varying estimates of vector control efficiency and extrinsic incubation period, "best-case" and "worst-case" scenarios of monthly R Epidemic potential (R We estimate that areas of north-eastern Australia could sustain local transmission of ZIKV. This early contribution to understanding the epidemic potential of ZIKV may assist in the assessment and management of threats to blood transfusion safety.
Publisher: Elsevier BV
Date: 05-2017
Publisher: Cambridge University Press (CUP)
Date: 16-01-2015
DOI: 10.1017/S095026881400380X
Abstract: We aimed to reparameterize and validate an existing dengue model, comprising an entomological component (CIMSiM) and a disease component (DENSiM) for application in Malaysia. With the model we aimed to measure the effect of importation rate on dengue incidence, and to determine the potential impact of moderate climate change (a 1 °C temperature increase) on dengue activity. Dengue models (comprising CIMSiM and DENSiM) were reparameterized for a simulated Malaysian village of 10 000 people, and validated against monthly dengue case data from the district of Petaling Jaya in the state of Selangor. Simulations were also performed for 2008-2012 for variable virus importation rates (ranging from 1 to 25 per week) and dengue incidence determined. Dengue incidence in the period 2010–2012 was modelled, twice, with observed daily weather and with a 1 °C increase, the latter to simulate moderate climate change. Strong concordance between simulated and observed monthly dengue cases was observed (up to r = 0·72). There was a linear relationship between importation and incidence. However, a doubling of dengue importation did not equate to a doubling of dengue activity. The largest in idual dengue outbreak was observed with the lowest dengue importation rate. Moderate climate change resulted in an overall decrease in dengue activity over a 3-year period, linked to high human seroprevalence early on in the simulation. Our results suggest that moderate reductions in importation with control programmes may not reduce the frequency of large outbreaks. Moderate increases in temperature do not necessarily lead to greater dengue incidence.
Publisher: Informa UK Limited
Date: 02-01-2015
Publisher: Wiley
Date: 04-12-2012
DOI: 10.1111/J.1365-2915.2012.01051.X
Abstract: New mosquito control strategies centred on the modifying of populations require knowledge of existing population densities at release sites and an understanding of breeding site ecology. Using a quantitative pupal survey method, we investigated production of the dengue vector Aedes aegypti (L.) (Stegomyia aegypti) (Diptera: Culicidae) in Cairns, Queensland, Australia, and found that garden accoutrements represented the most common container type. Deliberately placed 'sentinel' containers were set at seven houses and s led for pupae over 10 weeks during the wet season. Pupal production was approximately constant tyres and buckets represented the most productive container types. Sentinel tyres produced the largest female mosquitoes, but were relatively rare in the field survey. We then used field-collected data to make estimates of per premises population density using three different approaches. Estimates of female Ae. aegypti abundance per premises made using the container-inhabiting mosquito simulation (CIMSiM) model [95% confidence interval (CI) 18.5-29.1 females] concorded reasonably well with estimates obtained using a standing crop calculation based on pupal collections (95% CI 8.8-22.5) and using BG-Sentinel traps and a s ling rate correction factor (95% CI 6.2-35.2). By first describing local Ae. aegypti productivity, we were able to compare three separate population density estimates which provided similar results. We anticipate that this will provide researchers and health officials with several tools with which to make estimates of population densities.
Publisher: Wiley
Date: 19-04-2002
Publisher: MDPI AG
Date: 23-05-2022
Abstract: Citizen science mosquito surveillance has been growing in recent years due to both increasing concern about mosquito-borne disease and the increasing popularity of citizen science projects globally. Health authorities are recognising the potential importance of citizen science to expanding or enhancing traditional surveillance programs. Different programs have shown success in engaging communities to monitor species of medical importance through low-cost methods. The Mozzie Monitors project was established on iNaturalist—an open citizen science platform that allows participants to upload photos (i.e., observers) and assist identification (i.e., identifiers). This article describes the likelihood of citizen scientists submitting photos of mosquitoes, assesses user submission behaviour, and evaluates public health utility from these citizen science-derived data. From October 2018 to July 2021, the Mozzie Monitors project on iNaturalist received 2118 observations of 57 different species of mosquitoes across Australia. The number of observers in the system increased over time with more than 500 observers and 180 identifiers being active in the project since its establishment. Data showed species bias with large-bodied and colourful mosquitoes being over-represented. Analyses also indicate regional differentiation of mosquito fauna per state, seasonality of activity, and ecological information about mosquitoes. The iNaturalist citizen science platform also allows connectedness, facilitated communication and collaboration between overall users and expert entomologists, of value to medical entomology and mosquito management.
Publisher: Elsevier BV
Date: 10-2022
Publisher: Society for the Study of Amphibians and Reptiles
Date: 08-04-2020
DOI: 10.1670/19-048
Publisher: Public Library of Science (PLoS)
Date: 14-07-2020
Publisher: Wiley
Date: 17-06-2005
Publisher: Wiley
Date: 14-09-2011
DOI: 10.1111/J.1365-2915.2010.00908.X
Abstract: The Australian saltmarsh mosquito, Aedes c torhynchus (Diptera: Culicidae), is a significant biting pest and disease vector and is the subject of an eradication programme in New Zealand (NZ), where it has been resident for more than 10 years. To better understand the ecology of this common and widespread pest, we studied egg longevity and hatching patterns in the laboratory. By regularly testing for the presence of viable embryos, we found that eggs may last more than 15 months when stored dry (13% viable at this time). Eggs display instalment hatching, with no more than 56% of a batch hatching upon first inundation. Further hatching may occur for at least six inundations and some unhatched eggs may remain viable even after this. Variation in hatching rates can be observed using different water types, with weaker hatching media stimulating lower hatching rates spread over more inundations. By applying average hatching rates to a non-linear model of natural egg attrition, we showed that egg batches exposed to three inundations should be exhausted (zero live eggs present) in approximately 11 months at the conditions tested here. These findings have implications for the current eradication programme for Ae. c torhynchus in NZ and for our understanding of the ecology of a widespread and common disease vector in Australia.
Publisher: MDPI AG
Date: 07-09-2015
Publisher: Wiley
Date: 02-2012
Publisher: Wiley
Date: 23-12-2017
DOI: 10.1111/ZPH.12335
Abstract: Zoonotic diseases transmitted by arthropods and rodents are a major public health concern in China. However, interventions in recent decades have helped lower the incidence of several diseases despite the country's large, frequently mobile population and socio-economic challenges. Increasing globalization, rapid urbanization and a warming climate now add to the complexity of disease control and prevention and could challenge China's capacity to respond to threats of emerging and re-emerging zoonoses. To investigate this notion, face-to-face interviews were conducted with 30 infectious disease experts in four cities in China. The case study diseases under discussion were malaria, dengue fever and haemorrhagic fever with renal syndrome, all of which may be influenced by changing meteorological conditions. Data were analysed using standard qualitative techniques. The study participants viewed the current disease prevention and control system favourably and were optimistic about China's capacity to manage climate-sensitive diseases in the future. Several recommendations emerged from the data including the need to improve health literacy in the population regarding the transmission of infectious diseases and raising awareness of the health impacts of climate change amongst policymakers and health professionals. Participants thought that research capacity could be strengthened and human resources issues for front-line staff should be addressed. It was considered important that authorities are well prepared in advance for outbreaks such as dengue fever in populous subtropical areas, and a prompt and coordinated response is required when outbreaks occur. Furthermore, health professionals need to remain skilled in the identification of diseases for which incidence is declining, so that re-emerging or emerging trends can be rapidly identified. Recommendations such as these may be useful in formulating adaptation plans and capacity building for the future control and prevention of climate-sensitive zoonotic diseases in China and neighbouring countries.
Publisher: PeerJ
Date: 31-05-2022
DOI: 10.7717/PEERJ.13430
Abstract: Helicobacter pylori ( H. pylori ), a bacterium implicated in the development of peptic ulcer and gastric cancer, is estimated to infect around half the world’s population. Its prevalence in Australia is unclear. This scoping review aimed to evaluate all Australian literature providing estimates of the prevalence of H. pylori . Australian studies examining H. pylori prevalence from 1982 onwards were eligible for inclusion. Medline, Embase and Scopus databases, and grey literature sources, were searched. Two independent reviewers undertook a two-stage screening process. Data were extracted by two independent reviewers using a pre-specified template. Of 444 identified studies, 75 were included in the review. H. pylori prevalence in Australian population-based studies ( n = 8) ranged from 38.0% in 1991 to 15.1% in 2002 however, estimated prevalence across all non-clinical population studies in erse sub-groups ( n = 29) has varied dramatically. Decreased prevalence has been more marked in populations with gastrointestinal symptoms and conditions compared to non-clinical populations. Data on H. pylori prevalence in vulnerable populations are lacking. This is the first scoping review of Australian studies reporting H. pylori prevalence. A wide range of study designs, population groups, geographic regions, and diagnostic methods was included, involving data collected over a 50-year period (1969 to 2018). The summary of H. pylori prevalence estimates over time in this review points to a decrease in prevalence in Australia, particularly among populations with gastrointestinal symptoms and illnesses however, it is unknown whether there is inequity in prevalence trends across vulnerable sub-groups of the Australian population. Future research and interventions supporting the health and wellbeing of vulnerable populations is required to ensure equitable health gains are made for all.
Publisher: Informa UK Limited
Date: 2013
Publisher: Ubiquity Press, Ltd.
Date: 24-02-2022
DOI: 10.5334/CSTP.469
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.IJID.2015.02.010
Abstract: Haemorrhagic fever with renal syndrome (HFRS) is a rodent-borne disease that poses a serious public health threat in China. HFRS is caused by hantaviruses, mainly Seoul virus in urban areas and Hantaan virus in agricultural areas. Although preventive measures including vaccination programs and rodent control measures have resulted in a decline in cases in recent years, there has been an increase in incidence in some areas and new endemic areas have emerged. This review summarises the recent literature relating to the effects of climatic factors on the incidence of HFRS in China and discusses future research directions. Temperature, precipitation and humidity affect crop yields, rodent breeding patterns and disease transmission, and these can be influenced by a changing climate. Detailed surveillance of infections caused by Hantaan and Seoul viruses and further research on the viral agents will aid in interpretation of spatiotemporal patterns and a better understanding of the environmental and ecological drivers of HFRS amid China's rapidly urbanising landscape and changing climate.
Publisher: Informa UK Limited
Date: 02-01-2017
Publisher: The American Mosquito Control Association
Date: 03-2006
Publisher: Oxford University Press (OUP)
Date: 05-03-2015
DOI: 10.1093/JME/TJV004
Abstract: The presence of Aedes albopictus (Skuse) in the Torres Strait of northern Australia increases the potential for colonization and establishment on the mainland. However, there is a possibility that native species that occupy the same habitats may influence the population performance of Ae. albopictus, potentially affecting the establishment of this species in Australia. Cohabitation experiments were performed with the endemic Aedes notoscriptus (Skuse), which has been found occupying the same larval habitats as Ae. albopictus in the Torres Strait and is the most widespread container-inhabiting Aedes species in Australia. The influence of environmental factors and cohabitation between the two species was examined using different climates, food resource levels, food resource types, and species densities. Survivorship proportions and a population performance index (λ') were calculated and compared. The consequences of increased Ae. notoscriptus densities were reduced survivorship and λ' for Ae. albopictus. Despite this, the mean λ' of Ae. albopictus and Ae. notoscriptus was consistently ≥ 1.06, indicating both species could increase under all conditions, potentially due to increasing conspecific densities negatively affecting Ae. notoscriptus. The outcomes from this study suggest that the preexisting presence of Ae. notoscriptus may not prevent the establishment of Ae. albopictus in Australia.
Publisher: JSTOR
Date: 09-2000
DOI: 10.2307/1565367
Publisher: Wiley
Date: 06-2012
Publisher: Society for Vector Ecology
Date: 12-05-2014
DOI: 10.1111/J.1948-7134.2014.12082.X
Abstract: We investigated spatial autocorrelation of female Aedes aegypti L. mosquito abundance from BG-Sentinel trap and sticky ovitrap collections in Cairns, north Queensland, Australia. BG-Sentinel trap collections in 2010 show a significant spatial autocorrelation across the study site and over a smaller spatial extent, while sticky ovitrap collections only indicate a non-significant, weak spatial autocorrelation. The BG-Sentinel trap collections were suitable for spatial interpolation using ordinary kriging and cokriging techniques. The uses of Premise Condition Index and potential breeding container data have helped improve our prediction of vector abundance. Semiovariograms and prediction maps indicate that the spatial autocorrelation of mosquito abundance determined by BG-Sentinel traps extends farther compared to sticky ovitrap collections. Based on our data, fewer BG-Sentinel traps are required to represent vector abundance at a series of houses compared to sticky ovitraps. A lack of spatial structure was observed following vector control treatment in the area. This finding has implications for the design and costs of dengue vector surveillance programs.
Publisher: SAGE Publications
Date: 11-2011
Abstract: Vector surveillance is a cornerstone of dengue management yet there is a ersity of surveillance programs evident internationally. Such ersity is described in this review to enable a broader assessment of dengue vector surveillance methods. This review describes the ersity of surveillance programs for dengue vectors in several endemic and epidemic countries. Furthermore, strengths and weaknesses of vector surveillance methods, including larval surveys, BG-Sentinel trap, and autocidal and sticky ovitraps, are also discussed. The ability to compare and contrast these programs could contribute to the finding of better methods both locally and nationally and facilitate interregional technology transfer. Health authorities in both endemic and epidemic countries alike could benefit from adopting technologies and practices from other regions.
Publisher: Informa UK Limited
Date: 02-01-2017
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.JIPH.2018.12.010
Abstract: Dengue is a significant climate-sensitive disease. Public health professionals play an important role in prevention and control of the disease. This study aimed to explore dengue control and prevention in the context of climate change in China. A cross-sectional survey was conducted among 630 public health professionals in 2015. Descriptive analysis and logistic regression were performed. More than 80% of participants from southwest and central China believed climate change would affect dengue. However, participants from northeast China were less likely to believe so (65%). Sixty-nine percent of participants in Yunnan perceived that dengue had emerged/re-emerged in recent years, compared with 40.6% in Henan and 23.8% in Liaoning. Less than 60% of participants thought current prevention and control programs had been effective. Participants believed mosquitoes in high abundance, imported cases and climate change were main risk factors for dengue in China. There were varying views of dengue in China. Professionals in areas susceptible to dengue were more likely to be concerned about climate change and dengue. Current prevention and control strategies need to be improved. Providing more information for staff in lower levels of Centers for Disease Control and Prevention may help in containing a possible increase of dengue.
Publisher: Public Library of Science (PLoS)
Date: 19-09-2016
Publisher: Wiley
Date: 20-12-2010
Publisher: The American Mosquito Control Association
Date: 12-2006
Publisher: Elsevier BV
Date: 05-2014
DOI: 10.1016/J.TOXICON.2014.02.005
Abstract: Consumption of hibian eggs and larvae by crayfish has been widely reported despite many hibians being unpalatable and/or toxic to other predators. The aim of this review was to gather information regarding the consumption and/or avoidance of toxic hibians by these omnivores. We then appraised the extent of toxin consumptive ability in terms of crayfish phylogenetic history so as to speculate as to the evolutionary history of this trait. Reports indicating an ability to tolerate hibian toxins were collected and reviewed for 12 freshwater crayfish species. In reviewing these, we have established that freshwater crayfish appear to be tolerant of a range of toxic hibians, often consuming large numbers of eggs and larvae without lethal or apparent sublethal effects. Toxin tolerance was evident within both superfamilies (Astacoidea and Parastacoidea) suggesting that tolerance may be a primitive trait in freshwater crayfish.
Publisher: Cambridge University Press (CUP)
Date: 17-12-2018
DOI: 10.1017/S0950268817002254
Abstract: This study aims to investigate the climate–malaria associations in nine cities selected from malaria high-risk areas in China. Daily reports of malaria cases in Anhui, Henan, and Yunnan Provinces for 2005–2012 were obtained from the Chinese Center for Disease Control and Prevention. Generalized estimating equation models were used to quantify the city-specific climate–malaria associations. Multivariate random-effects meta-regression analyses were used to pool the city-specific effects. An inverted-U-shaped curve relationship was observed between temperatures, average relative humidity, and malaria. A 1 °C increase of maximum temperature ( T max ) resulted in 6·7% (95% CI 4·6–8·8%) to 15·8% (95% CI 14·1–17·4%) increase of malaria, with corresponding lags ranging from 7 to 45 days. For minimum temperature ( T min ), the effect estimates peaked at lag 0 to 40 days, ranging from 5·3% (95% CI 4·4–6·2%) to 17·9% (95% CI 15·6–20·1%). Malaria is more sensitive to T min in cool climates and T max in warm climates. The duration of lag effect in a cool climate zone is longer than that in a warm climate zone. Lagged effects did not vanish after an epidemic season but waned gradually in the following 2–3 warm seasons. A warming climate may potentially increase the risk of malaria resurgence in China.
Publisher: Oxford University Press (OUP)
Date: 05-12-2018
Abstract: Zoonotic vector-borne disease prevalence is affected by vector, human, and reservoir host factors, which are influenced by habitat and climate these 5 components interact on microhabitat-to-landscape scales but are often analyzed at a single spatial scale. We present an information theoretic, multiscale, multiple regression analysis of the ecological drivers of Ross River virus. We analyze the spatial pattern of 20 years of Ross River virus infections from South Australia (1992-2012 n = 5261), using variables across these 5 components of disease ecology at 3 spatial scales. We found that covariate importance depended on the spatial scale of the analysis some biotic variables were more important at fine scales and some abiotic variables were more important at coarser spatial scales. The urban score of an area was most predictive of infections, and mosquito variables did not improve the explanatory power of these models. Through this multiscale analysis, we identified novel drivers of the spatial distribution of disease and recommend public health interventions. Our results underline that single-scale analyses may paint an incomplete picture of disease drivers, potentially creating a major flaw in epidemiological analyses. Multiscale, ecological analyses are needed to better understand infectious disease transmission.
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.ENVRES.2016.03.043
Abstract: Dengue fever is an important climate-sensitive mosquito-borne viral disease that poses a risk to half the world's population. The disease is a major public health issue in China where in 2014 a major outbreak occurred in Guangdong Province. This study aims to gauge health professionals' perceptions about the capacity of infectious disease control and prevention to meet the challenge of dengue fever in the face of climate change in Guangdong Province, China. A cross-sectional questionnaire survey was administered among staff in the Centers for Disease Control and Prevention (CDCs) in Guangdong Province. Data analysis was undertaken using descriptive methods and logistic regression. In total, 260 questionnaires were completed. Most participants (80.7%) thought climate change would have a negative effect on population health, and 98.4% of participants reported dengue fever had emerged or re-emerged in China in recent years. Additionally, 74.9% of them indicated that the capability of the CDCs to detect infectious disease outbreak/epidemic at an early stage was excellent 86.3% indicated laboratories could provide diagnostic support rapidly and 83.1% believed levels of current staff would be adequate in the event of a major outbreak. Logistic regression analysis showed higher levels of CDCs were perceived to have better capacity for infectious disease control and prevention. Only 26.8% of participants thought they had a good understanding of climate change, and most (85.4%) thought they needed more information about the health impacts of climate change. Most surveyed staff suggested the following strategies to curb the public health impact of infectious diseases in relation to climate change: primary prevention measures, strengthening the monitoring of infectious diseases, the ability to actively forecast disease outbreaks by early warning systems, and more funding for public health education programs. Vigilant disease and vector surveillance, preventive practice and health promotion programs will likely be significant in addressing the threat of dengue fever in the future. Further efforts are needed to strengthen the awareness of climate change among health professionals, and to promote relevant actions to minimize the health burden of infectious diseases in a changing climate. Results will be critical for policy makers facing the current and future challenges associated with infectious disease prevention and control in China.
Publisher: The American Mosquito Control Association
Date: 06-2006
Publisher: Informa UK Limited
Date: 2013
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/ZO14026
Abstract: The primary aim of this study was to identify aquatic invertebrate predators of hibian eggs and tadpoles in an area of South Australia. The presence and abundance of aquatic invertebrates was monitored at four field sites for a period of 5–6 months this revealed notonectids, freshwater crayfish and odonates to be amongst the most common invertebrate predator types. The ability of these predators to consume eggs and tadpoles of the native Australian frogs Litoria ewingi and Crinia signifera was then investigated. Freshwater crayfish (Cherax destructor) were the most prolific consumers of frog eggs and tadpoles. The notonectid Enithares woodwardi significantly impacted tadpole survivorship for both species while Anisops sp. was less successful at capturing and consuming these tadpoles. Caddisfly nymphs (Lectrides varians and Leptorussa darlingtoni) reduced egg survivorship but not to the same extent as C. destructor. Unlike some predators, which prey upon particular life stages, freshwater crayfish are large, polytrophic omnivores that can act as important predators of both anuran eggs and tadpoles. Given that predation is a key source of mortality in juveniles, identification of likely common predators is useful for understanding the regulation of hibian populations.
Publisher: Oxford University Press (OUP)
Date: 03-02-2021
Abstract: Ross River virus (RRV) disease is Australia's most widespread vector-borne disease causing significant public health concern. The aim of this study was to identify the ecological covariates of RRV risk and to develop epidemic forecasting models in a disease hotspot region of South Australia. Seasonal autoregressive integrated moving average models were used to predict the incidence of RRV disease in the Riverland region of South Australia, an area known to have a high incidence of the disease. The model was developed using data from January 2000 to December 2012 then validated using disease notification data on reported cases for the following year. Monthly numbers of the mosquito Culex annulirostris (β=0.033, p& .001) and total rainfall (β=0.263, p=0.002) were significant predictors of RRV transmission in the study region. The forecasted RRV incidence in the predictive model was generally consistent with the actual number of cases in the study area. A predictive model has been shown to be useful in forecasting the occurrence of RRV disease, with increased vector populations and rainfall being important factors associated with transmission. This approach may be useful in a public health context by providing early warning of vector-borne diseases in other settings.
Publisher: Springer Science and Business Media LLC
Date: 06-10-2011
DOI: 10.1007/S00484-010-0400-7
Abstract: The aim of this study was to determine the climatic influences on floral development for five members of the Australian native plant genus Acrotriche R.Br (Ericaceae). An observed period of summer floral dormancy suggests temperature is involved in flowering regulation in these species. Models were developed to determine temperature requirements associated with the likelihood of flowering occurring on any one day. To this end, the timing of flowering and meteorological data were collated for several sites, and multivariate logistic regressions performed to identify variables with a significant influence on flowering timing. The resultant models described a large amount of variation in flowering presence/absence, with (r2) values ranging from 0.72 to 0.79. Temperature was identified as influential on both floral development and flowering timing in each of the study species. The positive influence of short photoperiods on flowering in three of the winter flowering species was not surprising. However, the reporting here ofa significant association between interdiurnal temperature and flowering in one species is novel. The predictive power of the models was validated through a jackknife sequential recalculation approach, revealing strong positive and negative predictive ability for flowering for four of the five species. Applications of the models include assisting in determination of the suitability of areas for vegetation restoration and identifying the possible effects of climate change on flowering in the study species.
Publisher: Mary Ann Liebert Inc
Date: 11-2022
Abstract: Japanese encephalitis virus (JEV) continues to cause significant numbers of human infections and fatalities despite the availability of efficacious vaccines. It is regarded as an emerging mosquito-borne pathogen with the potential of introduction into many countries. In 2022, JEV was detected in Australia on a hitherto unprecedented scale, with local transmission by indigenous mosquitoes to lifying swine hosts and to humans. In this study, we review this recent disease activity, propose possible routes of virus movement, ecological drivers of activity, and consider possible future transmission scenarios. Measures to enhance current surveillance systems and potential strategies for health authorities to minimize future risks are discussed.
Publisher: Springer Science and Business Media LLC
Date: 2014
Publisher: The American Mosquito Control Association
Date: 09-2006
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.SCITOTENV.2018.04.407
Abstract: This study aims to investigate the associations between meteorological factors and hemorrhagic fever with renal syndrome (HFRS) in 19 cities selected from HFRS high risk areas across different climate zones in three Provinces of China. De-identified daily reports of HFRS in Anhui, Heilongjiang, and Liaoning Provinces for 2005-2014 were obtained from the Chinese Center for Disease Control and Prevention. Daily weather data from each study location were obtained from the China meteorological Data Sharing Service System. Generalised estimating equation models (GEE) were used to quantify the city-specific HFRS-weather associations. Multivariate random-effects meta-regression models were used to pool the city-specific HFRS-weather effect estimates. HFRS showed an overall downward trend during the study period with a slight rebound after 2010. Meteorological factors were significantly associated with HFRS incidence. HFRS was relatively more sensitive to weather variability in subtropical regions (Anhui Province) than in temperate regions (Heilongjiang and Liaoning Provinces). The size of effect estimates and the duration of lagged effects varied by locations. Pooled results of the 19 cities showed that a 1 °C increase in maximum temperature (T
Publisher: The Royal Society
Date: 21-02-2006
Abstract: The search for novel insect repellents has been driven by health concerns over established synthetic compounds such as diethyl- m -toluamide (DEET). Given the ersity of compounds known from frog skin and records of mosquito bite and ectoparasite infestation, the presence of mosquito repellents in frogs seemed plausible. We investigated frog skin secretions to confirm the existence of mosquito repellent properties. Litoria caerulea secretions were assessed for mosquito repellency by topical application on mice. The secretions provided protection against host-seeking Culex annulirostris mosquitoes. Olfactometer tests using aqueous washes of skin secretions from L. caerulea and four other frog species were conducted to determine whether volatile components were responsible for repellency. Volatiles from Litoria rubella and Uperoleia mjobergi secretions were repellent to C. annulirostris , albeit not as repellent as a DEET control. The demonstration of endogenous insect repellents in hibians is novel, and demonstrates that many aspects of frog chemical ecology remain unexplored.
Publisher: The American Mosquito Control Association
Date: 03-2008
DOI: 10.2987/5658.1
Abstract: Lethal ovitraps (LO) have been successfully deployed in dengue control operations in north Queensland, Australia since 2004. However, the current plastic-bucket LO must be retrieved before the pesticide-treated strip degrades and the trap begins producing mosquitoes. The logistics involved with trap retrieval are considerable and include recording trap location and retrieval date onto a database, locating and retrieving each trap, and examining lethal ovitraps for eggs. Collectively, these necessary activities greatly reduce the efficiency of dengue control. In response, we have developed a biodegradable lethal ovitrap (BLO) that does not need to be retrieved for the control of container-breeding Aedes, particularly Aedes aegypti. The BLOs were made by injection molding with the use of 2 proprietary blends of thermoplastic starch (TPS) polymer based on plasticised amylose maize polymers. In field trials, Ae. aegypti readily oviposited in BLOs, with those dyed black with the use of carbon black preferred. Water loss was higher in BLOs than in standard plastic LO because of weeping from the walls, although none of the BLOs failed in the 5 wk of the trial. The occurrence and rate of Ae. aegypti oviposition in both BLOs and the LO was comparable. In an accelerated standard composting trial (ISO16929:2002E), both BLOs fragmented within 4 wk, and no BLO particles were visible after 12 wk. Large numbers of BLOs could be deployed in a "set it and forget it" strategy to control Ae. aegypti and to stop dengue transmission, and could be used in a community participation program to maximize coverage.
Publisher: Society for Vector Ecology
Date: 14-05-2018
DOI: 10.1111/JVEC.12288
Abstract: Mosquito-borne diseases are a pervasive public health problem on a global scale, and effective management of them requires well-designed surveillance programs for both vectors and pathogens. Mosquito traps are a common component of such programs, and their reach can be expanded by engaging citizen scientists. In this study in a southern Australian city, we compared the mosquito collection efficacy of two types of traps and assessed their suitability for use in citizen science programs. BG Sentinels and BG Gravid Aedes Trap (BG-GAT) traps both collected Aedes and Culex species in similar proportions, albeit with the former collecting approximately nine times as many mosquitoes. However, BG Sentinels have a greater per unit cost than BG-GATs and are restricted to deployment near power outlets. Importantly, despite being devised for collection of Aedes (Stegomyia) dengue vectors (such as Aedes aegypti), both traps can be effectively used in temperate climates for collection of a range of mosquito species. These traps could conceivably be used in citizen science programs to enhance the reach of surveillance at reduced cost.
Publisher: Society for Vector Ecology
Date: 27-11-2015
DOI: 10.1111/JVEC.12167
Abstract: Aedes aegypti (L.) mosquitoes preferentially oviposit in natural and artificial receptacles where their eggs are able to withstand drying as water levels fluctuate. Desiccation-resistant eggs also increase the potential for establishment in non-native habitats while providing logistical impediments to control programs. Viability and mean survival times of eggs stored under three dryness conditions for up to 367 days were investigated among three field-derived colonies of Australian Ae. aegypti to understand variation in desiccation survival. Further investigations compared egg survival between an established colony and its wild counterpart. Our results confirmed that Ae. aegypti eggs can withstand desiccation for extended periods of time with approximately 2-15% egg viability recorded after one year and viability remaining above 88% under all conditions through 56 days. Intraspecific variations in egg survival times were recorded, suggesting local adaptation while each of the colonies demonstrated a consistent preference for higher humidity. Egg volume varied between the populations, suggesting a relationship between egg volume and survival time, with the marginally larger eggs (Charters Towers and Innisfail) having greater desiccation resistance over the range of conditions. The strong survivorship of Charters Towers eggs in dry, warm conditions demonstrates the adaptive significance of a desiccation-resistant egg.
Publisher: Springer Science and Business Media LLC
Date: 26-07-2006
DOI: 10.1007/S10886-006-9097-9
Abstract: Previous investigations of Aedes aegypti response to human odor components have revealed a number of compounds that attract host-seeking females. However, such studies have utilized only a small number of long-term laboratory Ae. aegypti colonies. Using laboratory y-olfactometers, we studied the attraction of four different Ae. aegypti populations (North Queensland, Australia Florida, USA Singapore and Minas Gerais, Brazil) to a key attractant compound from human skin, lactic acid. Combinations of lactic acid with ammonia and a fatty acid (caproic acid) were also investigated. The aims were to determine the extent of variation in lactic acid dose response among populations and to see whether all four populations responded equally to combinations of human odor components. Although all Ae. aegypti populations were attracted to lactic acid, there were differences in the threshold dose: Florida 0.03 microg/min, Singapore 0.17 microg/min, North Queensland 1.92 microg/min, and Brazil 10.27 microg/min. Attraction to lactic acid alone (maximum 87% for all populations). Significant increases in attraction were observed when lactic acid was combined with ammonia or caproic acid, although not for all populations. In addition, the highest doses of caproic acid tested decreased attraction when combined with lactic acid. The ergent responses to host kairomones seen here may be evidence of adaptation to locally available hosts in different parts of the geographic range of Ae. aegypti.
Publisher: Wiley
Date: 17-11-2009
DOI: 10.1111/J.1365-2915.2009.00833.X
Abstract: We report on the first field evaluation of the public acceptability and performance of two types of lethal ovitrap (LO) in three separate trials in Cairns, Australia. Health workers were able to set standard lethal ovitraps (SLOs) in 75 and 71% of premise yards in the wet and dry season, respectively, and biodegradable lethal ovitraps (BLOs) in 93% of yards. Public acceptance, measured as retention of traps by residents, was high for both trap types, with <9% of traps missing after 4 weeks. Traps retaining water after 4 weeks were 78 and 34% for the two SLO trials and 58% for the BLOs. The 'failure rate' in the 535 BLOs set in the field for 4 weeks was 47%, of which 19% were lost, 51% had holes from probable insect chewing, 23% were knocked over, 7% had dried by evaporation and 1% were split. There was no significant difference in the failure rate of BLOs set on porous (grass, soil and mulch) versus solid (tiles, concrete, wood and stone) substrates. The SLOs and the BLOs were readily acceptable to ovipositing Aedes aegypti L. (Diptera: Culicidae) the mean number of eggs/trap was 6 and 15, for the dry season and wet season SLO trial, respectively, and 15 for the BLO wet season trial. Indeed, 84-94% of premise yards had egg positive SLOs or BLOs. A high percentage of both wet and dry season SLOs (29 and 70%, respectively) and BLOs (62%) that were dry after 4 weeks were egg positive, indicating the traps had functioned. Lethal strips from SLOs and BLOs that had been exposed for 4 weeks killed 83 and 74%, respectively, of gravid Ae. aegypti in laboratory assays. These results indicate that mass trapping schemes using SLOs and BLOs are not rejected by the public and effectively target gravid Ae. aegypti. The impact of the interventions on mosquito populations is described in a companion paper.
Publisher: Springer Science and Business Media LLC
Date: 2003
Abstract: The preference of two allopatric populations of Culex annulirostris mosquitoes in South Australia (SA) for guinea pigs and chickens was investigated using host-baited traps in the field and in a flight tunnel for laboratory assays. Mosquitoes from the Riverland of SA preferred guinea pigs, those from northeast SA preferred chickens. In the field, 2184 Cx. annulirostris were captured during four experiments in each region. The proportion choosing chicken was 0.5393 in northeast SA and 0.4348 in the Riverland. In the laboratory, replicate trials utilizing 15 mosquitoes at a time yielded results concordant with field assays. This study demonstrates variation in Cx. annulirostris host preference throughout this species geographic range. Semiochemical analysis of the two host species was performed on solvent extractions and volatile trapping s les from fur and feathers, respectively. This revealed differences that are likely to be the basis for host discrimination by Cx. annulirostris.
Publisher: SAGE Publications
Date: 03-2011
Abstract: Climate change will have significant and erse impacts on human health. These impacts will include changes in infectious disease incidence. In this article, the authors review the current situation and potential future climate change impacts for respiratory, diarrheal, and vector-borne diseases in Australia. Based on this review, the authors suggest adaptive strategies within the health sector and also recommend future research priorities.
Publisher: Wiley
Date: 07-2004
DOI: 10.1111/J.1751-0813.2004.TB11137.X
Abstract: To investigate the distribution and incidence of chytridiomycosis in eastern Australian frogs and to examine the effects of temperature on this disease. A pathological survey and a transmission experiment were conducted. Diagnostic pathology examinations were performed on free-living and captive, ill and dead hibians collected opportunistically from eastern Australia between October 1993 and December 2000. We conducted a transmission experiment in the laboratory to investigate the effects of temperature: eight great barred frogs (Mixophyes fasciolatus) exposed to zoospores of Batrachochytrium dendrobatidis and six unexposed frogs were housed in idually in each of three rooms held at 17 degrees C, 23 degrees C and 27 degrees C. Chytridiomycosis was the cause of death or morbidity for 133 (55.2%) of 241 free-living hibians and for 66 (58.4%) of 113 captive hibians. This disease occurred in 34 hibian species, was widespread around the eastern seaboard of Australia and affected hibians in a variety of habitats at high and low altitudes on or between the Great Dividing Range and the coast. The incidence of chytridiomycosis was higher in winter, with 53% of wild frogs from Queensland and New South Wales dying in July and August. Other diseases were much less common and were detected mostly in spring and summer. In experimental infections, lower temperatures enhanced the pathogenicity of B. dendrobatidis in M. fasciolatus. All 16 frogs exposed to B. dendrobatidis at 17 degrees C and 23 degrees C died, whereas 4 of 8 frogs exposed at 27 degrees C survived. However, the time until death for the frogs that died at 27 degrees C was shorter than at the lower temperatures. Infections in survivors were eliminated by 98 days. Chytridiomycosis is a major cause of mortality in free-living and captive hibians in Australia and mortality rate increases at lower temperatures.
Publisher: Informa UK Limited
Date: 03-07-2017
Publisher: Oxford University Press (OUP)
Date: 11-2008
DOI: 10.1603/0022-2585(2008)45[1173:REOAAP]2.0.CO;2
Abstract: New approaches for control of the dengue vector Aedes aegypti (L.) are being developed, including the potential introduction of life-shortening symbiont bacteria into field populations and the release of transgenic strains with reduced vector competency. With these new approaches comes the need for rapid estimations of existing field population size. Here, we describe the use of simulation modeling with container-inhabiting mosquito simulation (CIMSiM) for estimation of Ae. aegypti pupal crop size in north Queensland, Australia. CIMSiM was calibrated for local conditions by deploying "sentinel key containers" (tire, 2-liter plastic bucket, 0.6-liter pot plant base, and tarpaulin indentation) in which water flux and pupal productivity were studied for 72 d. Iterative adjustment of CIMSiM parameters was used to fit model outputs to match that of sentinel key containers. This calibrated model was then used in a blind field validation, in which breeding container and local meteorological data were used to populate CIMSiM, and model outputs were compared with a field pupal survey. Actual pupae per ha during two 10-d periods in 2007 fell within 95% confidence intervals of simulated pupal crop estimates made by 10 replicate simulations in CIMSiM, thus providing a successful field validation. Although the stochasticity of the field environment can never be wholly simulated, CIMSiM can provide field-validated estimates of pupal crop in a timely manner by using simple container surveys.
Publisher: Wiley
Date: 07-2014
DOI: 10.1890/13-1305.1
Abstract: A novel strategy for suppressing disease transmission by Aedes aegypti, the main vector of dengue, uses releases of mosquitoes infected with the bacterium Wolbachia pipientis. Wolbachia are currently released to interfere with viral transmission, but there is also potential to use strains in mosquito suppression and elimination programs via the deleterious effects of the bacterium on the host. Mosquito suppression depends on target areas being relatively isolated to prevent reinvasion and on local climatic conditions. Here we explored the opportunity for suppression of A. aegypti in central Queensland, Australia, by using microsatellite data and simulations based on CIMSiM models of local weather conditions and breeding container data. Our results indicate that Wolbachia-induced extinctions in central Queensland are possible, although they may eventually be compromised by ongoing mosquito migration between towns until these sources are also suppressed. The results highlight a novel use of deleterious Wolbachia infections to achieve ecological as well as disease-related endpoints.
Publisher: The Company of Biologists
Date: 15-05-2009
DOI: 10.1242/JEB.028951
Abstract: A virulent strain of the obligate intracellular bacterium Wolbachia pipientis that shortens insect lifespan has recently been transinfected into the primary mosquito vector of dengue virus, Aedes aegypti L. The microbe's ability to shorten lifespan and spread through host populations under the action of cytoplasmic incompatibility means it has the potential to be used as a biocontrol agent to reduce dengue virus transmission. Wolbachia is present in many host tissues and may have local effects on erse biological processes. In other insects, Wolbachiainfections have been shown to alter locomotor activity and response time to food cues. In mosquitoes, locomotor performance relates to the location of mates, human hosts, resting sites and oviposition sites. We have therefore examined the effect of the virulent, life-shortening Wolbachia strain wMelPop on the locomotion of Ae. aegypti as they age and as the pathogenicity of the infection increases. In parallel experiments we also examined CO2 production as a proxy for metabolic rate, to investigate a potential mechanistic explanation for any changes in locomotion. Contrary to expectation, we found that the infection increased activity and metabolic rate and that these effects were relatively consistent over the insect's lifespan. The results do not fit a standard model of bacterial pathogenesis in insects, and instead may reveal additional physiological changes induced by infection, such as either increased hunger or defects in the nervous system.
Publisher: The American Mosquito Control Association
Date: 12-2006
Publisher: Cambridge University Press (CUP)
Date: 22-07-2006
DOI: 10.1017/S0950268805004656
Abstract: To estimate the frequency of infectious gastroenteritis across Australia, and to identify risk factors, we conducted a national telephone survey of 6087 randomly selected respondents in 2001–2002. The case definition was three or more loose stools and/or two or more vomits in a 24-hour period in the last 4 weeks, with adjustment to exclude non-infectious causes and symptoms secondary to a respiratory infection. Frequency data were weighted to the Australian population. Multivariate logistic regression was used to assess potential risk factors including season, region, demographic and socioeconomic status. Among contacted in iduals, 67% responded. The case definition applied to 7% of respondents (450/6087) which extrapolates to 17·2 million (95% CI 14·5–19·9 million) cases of gastroenteritis in Australia in one year, or 0·92 (95% CI 0·77–1·06) cases erson per year. In the multivariate model, the odds of having gastroenteritis were increased in summer and in the warmest state, in young children, females, those with higher socioeconomic status and those without health insurance.
Publisher: Society for Vector Ecology
Date: 27-05-2016
DOI: 10.1111/JVEC.12194
Abstract: The Australian native mosquito Aedes (Finlaya) notoscriptus (Skuse) is closely associated with natural and artificial water holding receptacles. Eggs are laid in habitats where they are exposed to drying conditions as water levels fluctuate. Withstanding desiccation enables survival in challenging environments and increases the potential for establishment in non-native habitats. Until now, the desiccation resistance of Ae. notoscriptus eggs has been unknown despite the historical invasive success of this important dog heartworm and arbovirus vector. Viability and mean survival times of eggs from two Ae. notoscriptus populations (metropolitan areas of Sydney, NSW and Adelaide, SA) were evaluated, with eggs stored under three dryness conditions for up to 367 days. Our results revealed that Ae. notoscriptus eggs can withstand desiccation for extended periods, under a variety of conditions, with approximately 9-13% egg viability recorded after one year. This prolonged egg survival reflects the widespread distribution of this mosquito in Australia and its history of incursions and subsequent establishment in non-native habitats. Differences in mean egg volume were recorded in addition to significantly different egg length to width ratios for the two populations, which may reflect adaptation to biotope of origin and an associated likelihood of drought and drying conditions. The results of this study suggest that the desiccation resistant eggs of Ae. notoscriptus make this species highly adaptable, increasing the risk of movement to non-endemic regions of the world.
Publisher: Springer Science and Business Media LLC
Date: 2014
Publisher: Wiley
Date: 2007
DOI: 10.1002/JEZ.A.419
Abstract: Energy expenditure and water flux were measured in free-ranging alpacas Lama pacos, a South American camelid, on natural pastures of the Peruvian Andes (altitude: 4,400 m above sea level). Water influx rate (WIR) was estimated in 16 males (age 2 years, weight 48.5+/-8.6 kg) labelled with 2H. In addition, the field metabolic rate (FMR) was measured in four of these animals labelled with both an oxygen (18O) and a hydrogen (2H) isotope. The WIR averaged 3.62 L H2O/day and the mean total body water 33.1 kg, equal to 68.2% of body weight (BW). The FMR of the four doubly labelled animals was 14.05 MJ/day. New allometric equations were calculated describing the relationships between WIR or FMR and BW, respectively, including published data on ruminants and the present alpaca results. The regression equation indicates that daily WIR scales to a similar metabolic size (kilograms of BW(0.94)) in alpacas than in wild or domesticated ruminants and camelids originating from arid and semiarid habitats. The resulting regression equation for FMR explained over 99% of the variation and corresponded to the function FMR (kilojoules per day)=1079 (kilograms of BW0.668) (n=5, r2=0.995, P<0.001). The FMR measured in this study, the first reported for a South American camelid species, suggests that free-ranging alpacas have similar energy expenditures on a metabolic weight basis as other wild ruminants living under harsh climatic conditions.
Publisher: Springer Science and Business Media LLC
Date: 31-03-2017
Publisher: Society for Vector Ecology
Date: 21-04-2022
Publisher: Wiley
Date: 20-01-2018
DOI: 10.1111/JEB.13228
Abstract: The relationships between morphology, performance, behavior and ecology provide evidence for multiple and complex phenotypic adaptations. The anuran body plan, for ex le, is evolutionarily conserved and shows clear specializations to jumping performance back at least to the early Jurassic. However, there are instances of more recent adaptation to habit ersity in the post-cranial skeleton, including relative limb length. The present study tested adaptive models of morphological evolution in anurans associated with the ersity of microhabitat use (semi-aquatic arboreal, fossorial, torrent, and terrestrial) in species of anuran hibians from Brazil and Australia. We use phylogenetic comparative methods to determine which evolutionary models, including Brownian motion (BM) and Ornstein-Uhlenbeck (OU) are consistent with morphological variation observed across anuran species. Furthermore, this study investigated the relationship of maximum distance jumped as a function of components of morphological variables and microhabitat use. We found there are multiple optima of limb lengths associated to different microhabitats with a trend of increasing hindlimbs in torrent, arboreal, semi-aquatic whereas fossorial and terrestrial species evolve toward optima with shorter hindlimbs. Moreover, arboreal, semi-aquatic and torrent anurans have higher jumping performance and longer hindlimbs, when compared to terrestrial and fossorial species. We corroborate the hypothesis that evolutionary modifications of overall limb morphology have been important in the ersification of locomotor performance along the anuran phylogeny. Such evolutionary changes converged in different phylogenetic groups adapted to similar microhabitat use in two different zoogeographical regions.
Publisher: Mary Ann Liebert Inc
Date: 07-2015
Abstract: Spatially and temporally accurate information about infectious mosquito distribution allows for pre-emptive public health interventions that can reduce the burden of mosquito-borne infections on human populations. However, the labile nature of arboviruses, the low prevalence of infection in mosquitoes, the expensive labor costs for mosquito identification and sorting, and the specialized equipment required for arbovirus testing can obstruct arbovirus surveillance efforts. The recently developed techniques of testing mosquito expectorate using honey-baited nucleic acid preservation cards or sugar bait stations allows a sensitive method of testing for infectious, rather than infected, mosquito vectors. Here we report the results from the first large-scale incorporation of honey-baited cards into an existing mosquito surveillance program. During 4 months of the peak virus season (January-April, 2014) for a total of 577 trap nights, we set CO2-baited encephalitis vector survey (EVS) light traps at 88 locations in South Australia. The collection container for the EVS trap was modified to allow for the placement of a honey-baited nucleic acid preservation card (FTA™ card) inside. After collection, mosquitoes were maintained in a humid environment and allowed access to the cards for 1 week. Cards were then analyzed for common endemic Australian arboviruses using a nested RT-PCR. Eighteen virus detections, including 11 Ross River virus, four Barmah Forest virus, and three Stratford virus (not previously reported from South Australia) were obtained. Our findings suggest that adding FTA cards to an existing mosquito surveillance program is a rapid and efficient way of detecting infectious mosquitoes with high spatial resolution.
Publisher: Wiley
Date: 05-2005
Publisher: Wiley
Date: 15-10-2013
Publisher: Cambridge University Press (CUP)
Date: 2019
DOI: 10.1017/S095026881900030X
Abstract: Dengue infection in China has increased dramatically in recent years. Guangdong province (main city Guangzhou) accounted for more than 94% of all dengue cases in the 2014 outbreak. Currently, there is no existing effective vaccine and most efforts of control are focused on the vector itself. This study aimed to evaluate different dengue management strategies in a region where this disease is emerging. This work was done by establishing a dengue simulation model for Guangzhou to enable the testing of control strategies aimed at vector control and vaccination. For that purpose, the computer-based dengue simulation model (DENSiM) together with the Container-Inhabiting Mosquito Simulation Model (CIMSiM) has been used to create a working dengue simulation model for the city of Guangzhou. In order to achieve the best model fit against historical surveillance data, virus introduction scenarios were run and then matched against the actual dengue surveillance data. The simulation model was able to predict retrospective outbreaks with a sensitivity of 0.18 and a specificity of 0.98. This new parameterisation can now be used to evaluate the potential impact of different control strategies on dengue transmission in Guangzhou. The knowledge generated from this research would provide useful information for authorities regarding the historic patterns of dengue outbreaks, as well as the effectiveness of different disease management strategies.
Publisher: Informa UK Limited
Date: 15-06-2022
Publisher: Informa UK Limited
Date: 2012
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 06-2008
Publisher: Public Library of Science (PLoS)
Date: 14-08-2017
Publisher: Wiley
Date: 21-05-2009
Publisher: Cambridge University Press (CUP)
Date: 23-06-2016
DOI: 10.1017/S0950268816001357
Abstract: Epidemiological studies use georeferenced health data to identify disease clusters but the accuracy of this georeferencing is obfuscated by incorrectly assigning the source of infection and by aggregating case data to larger geographical areas. Often, place of residence (residence) is used as a proxy for the source of infection (source) which may not be accurate. Using a 21-year dataset from South Australia of human infections with the mosquito-borne Ross River virus, we found that 37% of cases were believed to have been acquired away from home. We constructed two risk maps using age-standardized morbidity ratios (SMRs) calculated using residence and patient-reported source. Both maps confirm significant inter-suburb variation in SMRs. Areas frequently named as the source (but not residence) and the highest-risk suburbs both tend to be tourist locations with vector mosquito habitat, and c ing or outdoor recreational opportunities. We suggest the highest-risk suburbs as places to focus on for disease control measures. We also use a novel application of ambient population data (LandScan) to improve the interpretation of these risk maps and propose how this approach can aid in implementing disease abatement measures on a smaller scale than for which disease data are available.
Publisher: Canadian Science Publishing
Date: 11-2014
Abstract: Freshwater crayfish are reported to consume early life-history stages of a number of toxic hibians. Although previous research indicates toxic hibians are palatable to crayfish, the potential toxicity associated with consumption of toxic prey has been poorly described. We sought to characterise the supposed tetrodotoxin (TTX) resistance of freshwater crayfish, which have been observed to eat the eggs and larvae of toxic Taricha Gray, 1850 newts. White river crayfish (Procambarus acutus (Girard, 1852)) consumed 7.7 ± 4.0 Rough-skinned Newt (Taricha granulosa (Skilton, 1849)) eggs (mean ± SD) when offered 10 eggs in controlled feeding trials. Eggs were determined to contain a concentration of 1239 ± 571 ng (mean ± SD) of TTX. A dose-response assay was then performed to compare ingested doses with physiological TTX resistance. Crayfish were highly susceptible to TTX when administered as an intramuscular injection TTX doses of 0.1 mass-adjusted mouse units were lethal to 100% of P. acutus crayfish. We established that while crayfish were capable consumers of highly toxic newt eggs, these decapods did not demonstrate physiological resistance to TTX. These findings suggest that crayfish have some functional resistance that renders them capable of consuming TTX-bearing prey despite a lack of physiological resistance to TTX.
Publisher: MDPI AG
Date: 22-12-2021
Abstract: The world is becoming increasingly urbanised, impacting human interactions with natural environments (NEs). NEs take a number of forms, ranging from pristine, modified, to built NEs, which are common in many urban areas. NEs may include nature-based solutions, such as introducing nature elements and biological processes into cities that are used to solve problems created by urbanisation. Whilst urbanisation has negative impacts on human health, impacting mental and physical wellbeing through a number of mechanisms, exposure to NEs may improve human health and wellbeing. Here, we review the mechanisms by which health can be improved by exposure to NEs, as explained by Stress Reduction Theory, Attention Restoration Theory, and the ‘Old Friends’/bio ersity hypothesis. Such exposures may have physiological and immunological benefits, mediated through endocrine pathways and altered microbiota. Citizen Science, which often causes exposure to NEs and social activity, is being increasingly used to not only collect scientific data but also to engage in iduals and communities. Despite being a named component of scientific and environmental strategies of governments, to our knowledge, the intrinsic health benefits of Citizen Science in NEs do not form part of public health policy. We contend that Citizen Science programs that facilitate exposure to NEs in urban areas may represent an important public health policy advance.
Publisher: SAGE Publications
Date: 03-09-2014
Abstract: This qualitative study aimed to describe field worker perceptions, evaluations of worth, and time costs of routine dengue vector surveillance methods in Cairns (Australia), Kuala Lumpur and Petaling District (Malaysia). In Cairns, the BG-Sentinel trap is a favored method for field workers because of its user-friendliness, but is not as cost-efficient as the sticky ovitrap. In Kuala Lumpur, the Mosquito Larvae Trapping Device is perceived as a solution for the inaccessibility of premises to larval surveys. Nonetheless, the larval survey method is retained in Malaysia for prompt detection of dengue vectors. For dengue vector surveillance to be successful, there needs to be not only technical, quantitative evaluations of method performance but also an appreciation of how amenable field workers are to using particular methods. Here, we report novel field worker perceptions of dengue vector surveillance methods in addition to time analysis for each method.
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.ENVRES.2016.11.009
Abstract: This study aims to (1) investigate the associations between climatic factors and dengue and (2) identify the susceptible subgroups. De-identified daily dengue cases in Guangzhou for 2005-2014 were obtained from the Chinese Center for Disease Control and Prevention. Weather data were downloaded from the China Meteorological Data Sharing Service System. Distributed lag non-linear models (DLNM) were used to graphically demonstrate the three-dimensional temperature-dengue association. Generalised estimating equation models (GEE) with piecewise linear spline functions were used to quantify the temperature-dengue associations. Threshold values were estimated using a broken-stick model. Middle-aged and older people, people undertaking household duties, retirees, and those unemployed were at high risk of dengue. Reversed U-shaped non-linear associations were found between ambient temperature, relative humidity, extreme wind velocity, and dengue. The optimal maximum temperature (T
Publisher: Wiley
Date: 15-07-2010
DOI: 10.1111/J.1365-3156.2010.02592.X
Abstract: To describe the meteorological influences on adult dengue vector abundance in Australia for the development of predictive models to trigger pre-emptive control operation. Multiple linear regression analyses were performed using meteorological data and female Aedes aegypti collection data from BG-Sentinel Mosquito traps placed at 11 monitoring sites in Cairns, north Queensland. Considerable regression coefficients (R(2) = 0.64 and 0.61) for longer- and shorter-term factor models respectively were derived. Longer-term factors significantly associated with abundance of adult vectors were mean minimum temperature (lagged 6 month) and mean daily temperature (lagged 4 month), explaining the predictable increase in abundance during the wet season. Factors explaining fluctuation in abundance in the shorter term were mean relative humidity over the previous 2 weeks and current daily average temperature. Rainfall variables were not found to be strong predictors of A. aegypti abundance in either longer- or shorter-term models. The implications of these findings for the development of useful predictive models for vector abundance risks are discussed. Such models can be used to guide the application of pre-emptive dengue vector control, and thereby enhance disease management.
Publisher: Wiley
Date: 11-01-2011
Publisher: Public Library of Science (PLoS)
Date: 06-08-2015
Publisher: Wiley
Date: 12-2005
DOI: 10.1111/J.1365-2915.2005.00589.X
Abstract: In Queensland, Australia, in response to isolated cases of dengue infection, larval control of the vector Aedes aegypti (L.) (Diptera: Culicidae) is targeted at breeding sites within 200 m of a case and interior spraying with a pyrethroid adulticide is targeted at premises within 100 m. To ascertain whether these limits are appropriate, we conducted a mark-release-recapture study to measure the dispersal of female Ae. aegypti in the city of Cairns where transmission occurs. Female mosquitoes reared from wild collected eggs were differentially marked with fluorescent dust depending on whether they were to be released blood-fed or non-blood-fed, and a total of 1,948 females was released. A total of 132 sticky ovitraps was set at 64 premises within a 200 m radius and collections of trapped adults were made at 5-15 days post-release. Sixty-seven females (3.4%) were recaptured, with the furthest being caught 200 m from the release point, and the mean distance travelled was 78 m. Overall, 23.1% of the recaptures outside the release site were taken beyond 100 m by day 15. Dispersal was comparable for both blood-fed and non-blood-fed releases. There was a significant tendency for dispersal to be in a north-westerly direction, probably because of the presence of numerous containers and heavy shading by trees in this direction and a busy road to the south of the release point that appeared to inhibit dispersal. The results suggest that adulticiding may have to be extended beyond 100 m if more than 8 days have elapsed since female Ae. aegypti could have fed upon a viraemic dengue case. The study also shows that dispersal is not random, and that it may be possible to maximize vector control by taking into account environmental factors that affect the direction of female mosquito flight.
Publisher: Wiley
Date: 11-2005
Publisher: Cambridge University Press (CUP)
Date: 26-07-2016
DOI: 10.1017/S095026881600162X
Abstract: Dengue is the world's most prevalent mosquito-borne disease, with more than 200 million people each year becoming infected. We used a mechanistic virus transmission model to determine whether climate warming would change dengue transmission in Australia. Using two climate models each with two carbon emission scenarios, we calculated future dengue epidemic potential for the period 2046–2064. Using the ECHAM5 model, decreased dengue transmission was predicted under the A2 carbon emission scenario, whereas some increases are likely under the B1 scenario. Dengue epidemic potential may decrease under climate warming due to mosquito breeding sites becoming drier and mosquito survivorship declining. These results contradict most previous studies that use correlative models to show increased dengue transmission under climate warming. Dengue epidemiology is determined by a complex interplay between climatic, human host, and pathogen factors. It is therefore naive to assume a simple relationship between climate and incidence, and incorrect to state that climate warming will uniformly increase dengue transmission, although in general the health impacts of climate change will be negative.
Publisher: American Society of Tropical Medicine and Hygiene
Date: 09-01-2013
Publisher: Wiley
Date: 12-02-2009
DOI: 10.1111/J.1365-2915.2008.00787.X
Abstract: Two mosquito species, Aedes c torhynchus (Thomson) and Aedes vigilax (Skuse) (Diptera: Culicidae) are responsible for significant nuisance biting and disease transmission in southern coastal Australia. Mosquito abundance, tide height, temperature and rainfall data were collected over three summer seasons (2002, 2003, 2004) at Port Pirie, South Australia and subjected to statistical analysis to develop ecological models for predicting problem mosquito outbreaks. A logistic regression model for Ae. c torhynchus gave a predictive R(2) of 0.30 using mean air temperature, whereas, for Ae. vigilax, tide height, mean air temperature and day length yielded a regression with an R(2) of 0.68. These models identify significant environmental drivers for both species and may be useful in the prediction of future outbreaks, particularly of Ae. vigilax.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.ENVINT.2019.105187
Abstract: Cities are home to over half the global population that proportion is expected to rise to 70% by mid-century. The urban environment differs greatly from that in which humans evolved, with potentially important consequences for health. Rates for allergic, inflammatory and auto-immune diseases appear to rise with urbanization and be higher in the more urbanized nations of the world which has led some to suggest that cities promote the occurrence of these diseases. However, there are no syntheses outlining what urban-associated diseases are and what characteristics of cities promote their occurrence. To synthesize the current understanding of "urban-associated diseases", and discover the common, potentially modifiable features of cities that may be driving these associations. We focus on any diseases that have been associated with cities or are particularly prominent in today's urban societies. We draw on expertise across erse health fields to examine the evidence for urban connections and drivers. We found evidence for urban associations across allergic, auto-immune, inflammatory, lifestyle and infectious disease categories. Some conditions (e.g. obesity and diabetes) have complex relationships with cities that have been insufficiently explored. Other conditions (e.g. allergies and asthma) have more evidence demonstrating their relationship with cities and the mechanisms driving that association. Unsurprisingly, air pollution was the characteristic of cities most frequently associated with disease. Other identified urban risk factors are not as widely known: altered microbial exposure and a disconnect from environmental microbiomes, vitamin D deficiency, noise and light pollution, and a transient, over-crowded, impoverished population. However, many complexities and caveats to these relationships beg clarification we highlight the current knowledge gaps and outline ways to fill those gaps. Identifying urban-associated diseases and their drivers will allow us to prepare for the urban-disease burden of the future and create healthy cities that mitigate that disease burden.
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.ASD.2016.01.009
Abstract: Aedes notoscriptus and Aedes aegypti are both peri-domestic, invasive container-breeding mosquitoes. While the two potential arboviral vectors are bionomically similar, their sympatric distribution in Australia is limited. In this study, analyses of Ae. aegypti and Ae. notoscriptus eggs were enabled using scanning electron microscopy. Significant variations in egg length to width ratio and outer chorionic cell field morphology between Ae. aegypti and Ae. notoscriptus enabled distinction of the two species. Intraspecific variations in cell field morphology also enabled differentiation of the separate populations of both species, highlighting regional and global variation. Our study provides a comprehensive comparative analysis of inter- and intraspecific egg morphological and morphometric variation between two invasive container-breeding mosquitoes. The results indicate a high degree of intraspecific variation in Ae. notoscriptus egg morphology when compared to the eggs of Ae. aegypti. Comparative morphological analyses of Ae. aegypti and Ae. notoscriptus egg attributes using SEM allows differentiation of the species and may be helpful in understanding egg biology in relation to biotope of origin.
Publisher: Society for Vector Ecology
Date: 23-05-2013
DOI: 10.1111/J.1948-7134.2013.12016.X
Abstract: Variability between Aedes aegypti populations in north Queensland, Australia, has the potential to impact the successful implementation of new population replacement mosquito releases for dengue control. Four Ae. aegypti colonies originating from different locations (Cairns, Mareeba, Innisfail, and Charters Towers), along with one F1 field-derived population from Cairns, were inter-crossed to determine any incompatibilities in copulation, insemination, and production of viable offspring. Greater copulation and insemination rates were observed when males recently introduced from the wild ('Cairns-Wild' population) were mated with long-term laboratory females. Egg viability rates for all crosses ranged from 90.2-98.2%, with no significant differences observed between crosses. Greater egg production was seen in some populations, and when corrected for wing-length, egg production was greatest in a Mareeba x Innisfail cross (19.55 eggs/mm wing length) and lowest for the Charters Towers intra-population cross (14.35 eggs/mm). Additionally, behavioral differences were observed between laboratory and wild mosquitoes from the Cairns location, suggesting possible laboratory conditioning. Finally, despite controlled larval rearing conditions, size differences between populations existed with Charters Towers mosquitoes consistently smaller than the other populations. The spread of genes or bacterial symbionts between these populations is unlikely to be hindered by pre-existing reproductive barriers.
Publisher: Public Library of Science (PLoS)
Date: 21-12-2010
Start Date: 2022
End Date: 12-2022
Amount: $361,354.00
Funder: Australian Research Council
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