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Ha TV, Kim W, Nguyen-Tien T, Lindahl J, Nguyen-Viet H, Thi NQ, Nguyen HV, Unger F, Lee HS. Spatial distribution of Culex mosquito abundance and associated risk factors in Hanoi, Vietnam. PLoS Negl Trop Dis 2021; 15:e0009497. [PMID: 34153065 PMCID: PMC8248591 DOI: 10.1371/journal.pntd.0009497] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 07/01/2021] [Accepted: 05/21/2021] [Indexed: 12/19/2022] Open
Abstract
Japanese encephalitis (JE) is the major cause of viral encephalitis (VE) in most Asian-Pacific countries. In Vietnam, there is no nationwide surveillance system for JE due to lack of medical facilities and diagnoses. Culex tritaeniorhynchus, Culex vishnui, and Culex quinquefasciatus have been identified as the major JE vectors in Vietnam. The main objective of this study was to forecast a risk map of Culex mosquitoes in Hanoi, which is one of the most densely populated cities in Vietnam. A total of 10,775 female adult Culex mosquitoes were collected from 513 trapping locations. We collected temperature and precipitation information during the study period and its preceding month. In addition, the other predictor variables (e.g., normalized difference vegetation index [NDVI], land use/land cover and human population density), were collected for our analysis. The final model selected for estimating the Culex mosquito abundance included centered rainfall, quadratic term rainfall, rice cover ratio, forest cover ratio, and human population density variables. The estimated spatial distribution of Culex mosquito abundance ranged from 0 to more than 150 mosquitoes per 900m2. Our model estimated that 87% of the Hanoi area had an abundance of mosquitoes from 0 to 50, whereas approximately 1.2% of the area showed more than 100 mosquitoes, which was mostly in the rural/peri-urban districts. Our findings provide better insight into understanding the spatial distribution of Culex mosquitoes and its associated environmental risk factors. Such information can assist local clinicians and public health policymakers to identify potential areas of risk for JE virus. Risk maps can be an efficient way of raising public awareness about the virus and further preventive measures need to be considered in order to prevent outbreaks and onwards transmission of JE virus.
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Affiliation(s)
- Tuyen V. Ha
- Faculty of Resources Management, Thai Nguyen University of Agriculture and Forestry (TUAF), Thai Nguyen, Vietnam
| | - Wonkook Kim
- Pusan National University, Busan, South Korea
| | | | - Johanna Lindahl
- International Livestock Research Institute (ILRI), Hanoi, Vietnam
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Hung Nguyen-Viet
- International Livestock Research Institute (ILRI), Hanoi, Vietnam
| | - Nguyen Quang Thi
- Faculty of Resources Management, Thai Nguyen University of Agriculture and Forestry (TUAF), Thai Nguyen, Vietnam
| | - Huy Van Nguyen
- Faculty of Resources Management, Thai Nguyen University of Agriculture and Forestry (TUAF), Thai Nguyen, Vietnam
| | - Fred Unger
- International Livestock Research Institute (ILRI), Hanoi, Vietnam
| | - Hu Suk Lee
- International Livestock Research Institute (ILRI), Hanoi, Vietnam
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Koolhof IS, Firestone SM, Bettiol S, Charleston M, Gibney KB, Neville PJ, Jardine A, Carver S. Optimising predictive modelling of Ross River virus using meteorological variables. PLoS Negl Trop Dis 2021; 15:e0009252. [PMID: 33690616 PMCID: PMC7978384 DOI: 10.1371/journal.pntd.0009252] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 03/19/2021] [Accepted: 02/17/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Statistical models are regularly used in the forecasting and surveillance of infectious diseases to guide public health. Variable selection assists in determining factors associated with disease transmission, however, often overlooked in this process is the evaluation and suitability of the statistical model used in forecasting disease transmission and outbreaks. Here we aim to evaluate several modelling methods to optimise predictive modelling of Ross River virus (RRV) disease notifications and outbreaks in epidemiological important regions of Victoria and Western Australia. METHODOLOGY/PRINCIPAL FINDINGS We developed several statistical methods using meteorological and RRV surveillance data from July 2000 until June 2018 in Victoria and from July 1991 until June 2018 in Western Australia. Models were developed for 11 Local Government Areas (LGAs) in Victoria and seven LGAs in Western Australia. We found generalised additive models and generalised boosted regression models, and generalised additive models and negative binomial models to be the best fit models when predicting RRV outbreaks and notifications, respectively. No association was found with a model's ability to predict RRV notifications in LGAs with greater RRV activity, or for outbreak predictions to have a higher accuracy in LGAs with greater RRV notifications. Moreover, we assessed the use of factor analysis to generate independent variables used in predictive modelling. In the majority of LGAs, this method did not result in better model predictive performance. CONCLUSIONS/SIGNIFICANCE We demonstrate that models which are developed and used for predicting disease notifications may not be suitable for predicting disease outbreaks, or vice versa. Furthermore, poor predictive performance in modelling disease transmissions may be the result of inappropriate model selection methods. Our findings provide approaches and methods to facilitate the selection of the best fit statistical model for predicting mosquito-borne disease notifications and outbreaks used for disease surveillance.
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Affiliation(s)
- Iain S. Koolhof
- College of Health and Medicine, School of Medicine, University of Tasmania, Hobart, Tasmania, Australia
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
- * E-mail:
| | - Simon M. Firestone
- Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Silvana Bettiol
- College of Health and Medicine, School of Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Michael Charleston
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Katherine B. Gibney
- Victorian Department of Health and Human Services, Communicable Disease Epidemiology and Surveillance, Health Protection Branch, Melbourne, Victoria, Australia
| | - Peter J. Neville
- Victorian Department of Health and Human Services, Communicable Disease Epidemiology and Surveillance, Health Protection Branch, Melbourne, Victoria, Australia
- Department of Health, Western Australia, Environmental Health Directorate, Public and Aboriginal Health Division, Perth, Western Australia, Australia
| | - Andrew Jardine
- Department of Health, Western Australia, Environmental Health Directorate, Public and Aboriginal Health Division, Perth, Western Australia, Australia
| | - Scott Carver
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
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Murphy AK, Clennon JA, Vazquez-Prokopec G, Jansen CC, Frentiu FD, Hafner LM, Hu W, Devine GJ. Spatial and temporal patterns of Ross River virus in south east Queensland, Australia: identification of hot spots at the rural-urban interface. BMC Infect Dis 2020; 20:722. [PMID: 33008314 PMCID: PMC7530966 DOI: 10.1186/s12879-020-05411-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 09/10/2020] [Indexed: 12/02/2022] Open
Abstract
Background Ross River virus (RRV) is responsible for the most common vector-borne disease of humans reported in Australia. The virus circulates in enzootic cycles between multiple species of mosquitoes, wildlife reservoir hosts and humans. Public health concern about RRV is increasing due to rising incidence rates in Australian urban centres, along with increased circulation in Pacific Island countries. Australia experienced its largest recorded outbreak of 9544 cases in 2015, with the majority reported from south east Queensland (SEQ). This study examined potential links between disease patterns and transmission pathways of RRV. Methods The spatial and temporal distribution of notified RRV cases, and associated epidemiological features in SEQ, were analysed for the period 2001–2016. This included fine-scale analysis of disease patterns across the suburbs of the capital city of Brisbane, and those of 8 adjacent Local Government Areas, and host spot analyses to identify locations with significantly high incidence. Results The mean annual incidence rate for the region was 41/100,000 with a consistent seasonal peak in cases between February and May. The highest RRV incidence was in adults aged from 30 to 64 years (mean incidence rate: 59/100,000), and females had higher incidence rates than males (mean incidence rates: 44/100,000 and 34/100,000, respectively). Spatial patterns of disease were heterogeneous between years, and there was a wide distribution of disease across both urban and rural areas of SEQ. Overall, the highest incidence rates were reported from predominantly rural suburbs to the north of Brisbane City, with significant hot spots located in peri-urban suburbs where residential, agricultural and conserved natural land use types intersect. Conclusions Although RRV is endemic across all of SEQ, transmission is most concentrated in areas where urban and peri-urban environments intersect. The drivers of RRV transmission across rural-urban landscapes should be prioritised for further investigation, including identification of specific vectors and hosts that mediate human spillover.
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Affiliation(s)
- Amanda K Murphy
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia. .,School of Biomedical Sciences, Faculty of Health, and Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
| | - Julie A Clennon
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, USA
| | | | - Cassie C Jansen
- Communicable Diseases Branch, Queensland Health, Herston, Australia
| | - Francesca D Frentiu
- School of Biomedical Sciences, Faculty of Health, and Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - Louise M Hafner
- School of Biomedical Sciences, Faculty of Health, and Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - Wenbiao Hu
- School of Public Health and Social Work, Queensland University of Technology, Brisbane, Australia
| | - Gregor J Devine
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
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Skinner EB, Murphy A, Jansen CC, Shivas MA, McCallum H, Onn MB, Reid SA, Peel AJ. Associations Between Ross River Virus Infection in Humans and Vector-Vertebrate Community Ecology in Brisbane, Australia. Vector Borne Zoonotic Dis 2020; 20:680-691. [PMID: 32366183 DOI: 10.1089/vbz.2019.2585] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Transmission of vector-borne pathogens can vary in complexity from single-vector, single-host systems through to multivector, multihost vertebrate systems. Understanding the dynamics of transmission is important for disease prevention efforts, but is dependent on disentangling complex interactions within coupled natural systems. Ross River virus (RRV) is a multivector multihost pathogen responsible for the greatest number of notified vector-borne pathogen infections in humans in Australia. Current evidence suggests that nonhuman vertebrates are critical for the maintenance and spillover of RRV into mosquito populations. Yet, there is a limited knowledge of which mosquito vector species and amplifying vertebrate host species are most important for transmission of RRV to humans. We conducted field surveys of nonhuman vertebrates and mosquitoes in the RRV endemic city of Brisbane, Australia, to assess the effect of vector and host community structure on human RRV notifications. Six suburbs were selected across a gradient of human disease notification rates. Differences in vertebrate and mosquito compositions were observed across all suburbs. Suburbs with higher RRV notification rates contained greater vertebrate biomass (dominated by the presence of horses) and higher mosquito abundances. This study suggests that horse-mosquito interactions should be considered in more detail and that vertebrate biomass and mosquito abundance be incorporated into future RRV modeling studies and considered in public health strategies for RRV management.
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Affiliation(s)
- Eloise B Skinner
- Environmental Futures Research Institute, Griffith University, Nathan, Queensland, Australia
| | - Amanda Murphy
- School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia.,QIMR Berghofer Medical Research Institute, Mosquito Control Laboratory, Herston, Queensland, Australia
| | - Cassie C Jansen
- Communicable Diseases Branch, Queensland Health, Herston, Queensland, Australia
| | - Martin A Shivas
- Brisbane City Council, Field Services, Brisbane CBD, Queensland, Australia
| | - Hamish McCallum
- Environmental Futures Research Institute, Griffith University, Nathan, Queensland, Australia
| | - Michael B Onn
- Brisbane City Council, Field Services, Brisbane CBD, Queensland, Australia
| | - Simon A Reid
- School of Public Health, The University of Queensland, Herston, Queensland, Australia
| | - Alison J Peel
- Environmental Futures Research Institute, Griffith University, Nathan, Queensland, Australia
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Walker LJ, Selvey LA, Jardine A, Johansen CA, Lindsay MDA. Mosquito and Virus Surveillance as a Predictor of Human Ross River Virus Infection in South-West Western Australia: How Useful Is It? Am J Trop Med Hyg 2019; 99:1066-1073. [PMID: 30182918 DOI: 10.4269/ajtmh.18-0459] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Mosquito and virus surveillance systems are widely used in Western Australia (WA) to support public health efforts to reduce mosquito-borne disease. However, these programs are costly to maintain on a long-term basis. Therefore, we aimed to assess the validity of mosquito numbers and Ross River virus (RRV) isolates from surveillance trap sites as predictors of human RRV cases in south-west WA between 2003 and 2014. Using negative binomial regression modeling, mosquito surveillance was found to be a useful tool for predicting human RRV cases. In eight of the nine traps, when adjusted for season, there was an increased risk of RRV cases associated with elevated mosquito numbers detected 1 month before the onset of human cases for at least one quartile compared with the reference group. The most predictive urban trap sites were located near saltmarsh mosquito habitat, bushland that could sustain macropods and densely populated residential suburbs. This convergence of environments could allow enzootic transmission of RRV to spillover and infect the human population. Close proximity of urban trap sites to each other suggested these sites could be reduced. Ross River virus isolates were infrequent at some trap sites, so ceasing RRV isolation from mosquitoes at these sites or where isolates were not predictive of human cases could be considered. In future, trap sites could be reduced for routine surveillance, allowing other environments to be monitored to broaden the understanding of RRV ecology in the region. A more cost-effective and efficient surveillance program may result from these modifications.
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Affiliation(s)
- Liz J Walker
- National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australia
| | - Linda A Selvey
- Faculty of Medicine, School of Public Health, The University of Queensland, Brisbane, Australia
| | - Andrew Jardine
- Environmental Health Hazards Unit, Environmental Health Directorate, Public and Aboriginal Health Division, Department of Health Western Australia, Perth, Australia
| | - Cheryl A Johansen
- The University of Western Australia, Nedlands, Western Australia, Australia and PathWest Laboratory Medicine Western Australia, Department of Health Western Australia, Nedlands, Australia
| | - Michael D A Lindsay
- Environmental Health Hazards Unit, Environmental Health Directorate, Public and Aboriginal Health Division, Department of Health Western Australia, Perth, Australia
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Webb CE, Russell RC. Dispersal of the Mosquito Aedes vigilax (Diptera: Culicidae) From Urban Estuarine Wetlands in Sydney, Australia. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:1290-1295. [PMID: 31095691 DOI: 10.1093/jme/tjz054] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Indexed: 06/09/2023]
Abstract
Aedes vigilax (Skuse) is a pest and vector species associated with coastal wetlands and the abundance of this mosquito has been identified as contributing to increased risk of mosquito-borne disease outbreaks. As urban development continues to encroach on these coastal wetlands, pest and public health impacts are becoming of increasing concern and in the absence of broadscale mosquito control. Urban planners are looking to buffer zones and other land use planning options to minimize contact between mosquitoes and humans but gaps in the understanding of dispersal ranges of mosquitoes hamper the adoption of these strategies. A mark-release-recapture experiment was conducted to measure the dispersal of this mosquito from an urban estuarine wetland in Sydney, Australia. An estimated total of over 150,000 wild caught female mosquitoes were marked with fluorescent dust and then released. A network of 38 traps was then operated for 5 d within an area of 28 km2. A total of 280 marked mosquitoes was recaptured, representing less than 1% of the estimate 250,000 marked mosquitoes released. Marked mosquitoes were recaptured up to 3 km from the release point, providing an insight into the dispersal range of these mosquitoes. The mean distance traveled by marked mosquitoes was 0.83 km, a result reflecting the greater proportion of marked mosquitoes recaptured near release point. The findings of this study indicate that effective buffer zones between estuarine wetlands and high-density urban developments would be an impractical approach to minimizing pest and public health impacts associated with this mosquito.
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Affiliation(s)
- Cameron E Webb
- Department of Medical Entomology, Westmead Hospital, University of Sydney, Westmead, NSW, Australia
- Marie Bashir Institute of Infectious Diseases and Biosecurity, University of Sydney, NSW, Australia
- NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia
| | - Richard C Russell
- Department of Medical Entomology, Westmead Hospital, University of Sydney, Westmead, NSW, Australia
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Mackenzie JS, Lindsay MDA, Smith DW, Imrie A. The ecology and epidemiology of Ross River and Murray Valley encephalitis viruses in Western Australia: examples of One Health in Action. Trans R Soc Trop Med Hyg 2018; 111:248-254. [PMID: 29044370 PMCID: PMC5914307 DOI: 10.1093/trstmh/trx045] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 07/27/2017] [Indexed: 01/02/2023] Open
Abstract
Arboviruses are maintained and transmitted through an alternating biological cycle in arthropods and vertebrates, with largely incidental disease in humans and animals. As such, they provide excellent examples of One Health, as their health impact is inextricably linked to their vertebrate hosts, their arthropod vectors and the environment. Prevention and control requires a comprehensive understanding of these interactions, and how they may be effectively and safely modified. This review concentrates on human disease due to Ross River and Murray Valley encephalitis viruses, the two major arboviral pathogens in Australia. It describes how their pattern of infection and disease is influenced by natural climatic and weather patterns, and by anthropogenic activities. The latter includes human-mediated environmental manipulations, such as water impoundment infrastructures, human movements and migration, and community and social changes, such as urban spread into mosquito larval habitats. Effective interventions need to be directed at the environmental precursors of risk. This can best be achieved using One Health approaches to improve collaboration and coordination between different disciplines and cross-sectoral jurisdictions in order to develop more holistic mitigation and control procedures, and to address poorly understood ecological issues through multidisciplinary research.
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Affiliation(s)
- John S Mackenzie
- Department of Microbiology, PathWest Laboratory Medicine WA, QEII Medical Centre, Nedlands, WA 6009
- Faculty of Health Sciences, Curtin University, GPO Box U1987, Perth, WA 6845
- Corresponding author: Present address: 5E, 16 Kings Park Avenue, Crawley, WA 6009; Tel: +61 439 875 697; E-mail:
| | - Michael D A Lindsay
- Public and Aboriginal Health Division, Department of Health, Grace Vaughan House, Shenton Park, Western Australia, WA 6008
| | - David W Smith
- Department of Microbiology, PathWest Laboratory Medicine WA, QEII Medical Centre, Nedlands, WA 6009
- Faculty of Medicine and Health Sciences, University of Western Australia, Nedlands, WA 6009, Australia
| | - Allison Imrie
- Department of Microbiology, PathWest Laboratory Medicine WA, QEII Medical Centre, Nedlands, WA 6009
- Faculty of Medicine and Health Sciences, University of Western Australia, Nedlands, WA 6009, Australia
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Walsh MG, Webb C. Hydrological features and the ecological niches of mammalian hosts delineate elevated risk for Ross River virus epidemics in anthropogenic landscapes in Australia. Parasit Vectors 2018; 11:192. [PMID: 29554980 PMCID: PMC5859420 DOI: 10.1186/s13071-018-2776-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 03/06/2018] [Indexed: 11/20/2022] Open
Abstract
Background The current understanding of the landscape epidemiology of Ross River virus (RRV), Australia’s most common arthropod-borne pathogen, is fragmented due to gaps in surveillance programs and the relatively narrow focus of the research conducted to date. This leaves public health agencies with an incomplete understanding of the spectrum of infection risk across the diverse geography of the Australian continent. The current investigation sought to assess the risk of RRV epidemics based on abiotic and biotic landscape features in anthropogenic landscapes, with a particular focus on the influence of water and wildlife hosts. Methods Abiotic features, including hydrology, land cover and altitude, and biotic features, including the distribution of wild mammalian hosts, were interrogated using a Maxent model to discern the landscape suitability to RRV epidemics in anthropogenically impacted environments across Australia. Results Water-soil balance, proximity to controlled water reservoirs, and the ecological niches of four species (Perameles nasuta, Wallabia bicolor, Pseudomys novaehollandiae and Trichosurus vulpecula) were important features identifying high risk landscapes suitable for the occurrence of RRV epidemics. Conclusions These results help to delineate human infection risk and thus provide an important perspective for geographically targeted vector, wildlife, and syndromic surveillance within and across the boundaries of local health authorities. Importantly, our analysis highlights the importance of the hydrology, and the potential role of mammalian host species in shaping RRV epidemic risk in peri-urban space. This study offers novel insight into wildlife hosts and RRV infection ecology and identifies those species that may be beneficial to future targeted field surveillance particularly in ecosystems undergoing rapid change. Electronic supplementary material The online version of this article (10.1186/s13071-018-2776-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael G Walsh
- Marie Bashir Institute for Infectious Diseases and Biosecurity, Westmead Institute for Medical Research, University of Sydney, Westmead, New South Wales, Australia.
| | - Cameron Webb
- Marie Bashir Institute for Infectious Diseases and Biosecurity, Westmead Institute for Medical Research, University of Sydney, Westmead, New South Wales, Australia.,Department of Medical Entomology, NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia
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Flies EJ, Weinstein P, Anderson SJ, Koolhof I, Foufopoulos J, Williams CR. Ross River Virus and the Necessity of Multiscale, Eco-epidemiological Analyses. J Infect Dis 2017; 217:807-815. [DOI: 10.1093/infdis/jix615] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Fine-temporal forecasting of outbreak probability and severity: Ross River virus in Western Australia. Epidemiol Infect 2017; 145:2949-2960. [DOI: 10.1017/s095026881700190x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
SUMMARYHealth warnings of mosquito-borne disease risk require forecasts that are accurate at fine-temporal resolutions (weekly scales); however, most forecasting is coarse (monthly). We use environmental and Ross River virus (RRV) surveillance to predict weekly outbreak probabilities and incidence spanning tropical, semi-arid, and Mediterranean regions of Western Australia (1991–2014). Hurdle and linear models were used to predict outbreak probabilities and incidence respectively, using time-lagged environmental variables. Forecast accuracy was assessed by model fit and cross-validation. Residual RRV notification data were also examined against mitigation expenditure for one site, Mandurah 2007–2014. Models were predictive of RRV activity, except at one site (Capel). Minimum temperature was an important predictor of RRV outbreaks and incidence at all predicted sites. Precipitation was more likely to cause outbreaks and greater incidence among tropical and semi-arid sites. While variable, mitigation expenditure coincided positively with increased RRV incidence (r2 = 0·21). Our research demonstrates capacity to accurately predict mosquito-borne disease outbreaks and incidence at fine-temporal resolutions. We apply our findings, developing a user-friendly tool enabling managers to easily adopt this research to forecast region-specific RRV outbreaks and incidence. Approaches here may be of value to fine-scale forecasting of RRV in other areas of Australia, and other mosquito-borne diseases.
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Mainali S, Lamichhane RS, Clark K, Beatty S, Fatouros M, Neville P, Oosthuizen J. "Looking over the Backyard Fence": Householders and Mosquito Control. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14030246. [PMID: 28257079 PMCID: PMC5369082 DOI: 10.3390/ijerph14030246] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/22/2017] [Accepted: 02/23/2017] [Indexed: 11/16/2022]
Abstract
(1) Background: Vector-borne diseases are a significant public health problem in Western Australia. Mosquitoes are responsible for the transmission of a number of pathogens and may pose a serious nuisance problem. Prevention efforts in the State are multi-faceted and include physical, chemical, and cultural control methods for restricting mosquito breeding. This is less complex where breeding areas are located within public open spaces. In Australia's developed urban areas, breeding sites are, however, frequently located within private residential landholdings, where the scope of public health officials to act is constrained by law and practicality. Consequently, mosquito prevention in these locations is predominantly the responsibility of the residents. This research addressed a gap, both in understanding the degree to which "backyard" mosquito breeding has the potential to contribute to local mosquito problems, and in assessing what residents "think and do" about mosquito control within their home environment. (2) Methods: The study was conducted in the Town of Bassendean, a metropolitan Local Government Area of Perth, Western Australia, in close proximity to two natural, productive mosquito breeding sites, namely Ashfield Flats and Bindaring Park. A total of 150 householders were randomly surveyed during the summer of 2015-2016, to gauge residents' knowledge, attitudes, and practices (KAP (knowledge, attitudes, and practices) Survey) in regards to mosquitoes, their breeding and ecology, and avoidance or minimization strategies. The survey comprised nine questions covering residents' knowledge (3 questions), attitudes (3 questions), and practices (3 questions), as well as additional questions regarding the basic demographics of the resident. Larvae were collected from backyard containers and reared to adults for species identification. A series of Encephalitis Vector Surveillance carbon dioxide (EVS CO₂) traps were also deployed, to assess adult mosquito density and species composition. (3) Results: Aedes notoscriptus (Skuse), a known container-inhabiting species, accounted for just over 50% of all mosquitoes identified. Most residents were aware of mosquito-borne disease and its risk in their local area. While the majority (79%) of the sample correctly identified Ross River virus as the most common infection in WA, a significant gap in the general knowledge of residents in regards to mosquito biology and breeding habits, was noted. Furthermore, only 50% of residents reported using personal protective measures to reduce mosquito bites and only one in six residents undertook physical or chemical mosquito control around their home. Additionally, 60% of respondents believed that mosquito control was "a job for the council and the state government", rather than for individual householders. (4) Conclusions: A significant gap in the knowledge of residents in the study area existed in regards to the general knowledge of mosquitoes and their breeding habits; types of treatments that could be employed within the home; and the residents' responsibility for the management of mosquito breeding on their private property. A public education campaign has been deployed to educate the residents.
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Affiliation(s)
- Samir Mainali
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia.
| | - Ram Sharan Lamichhane
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia.
| | - Kim Clark
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia.
| | - Shelley Beatty
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia.
| | | | - Peter Neville
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia.
- Health Department of Western Australia, Perth, WA 6000, Australia.
| | - Jacques Oosthuizen
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia.
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Improving public health intervention for mosquito-borne disease: the value of geovisualization using source of infection and LandScan data. Epidemiol Infect 2016; 144:3108-3119. [DOI: 10.1017/s0950268816001357] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
SUMMARYEpidemiological 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 camping 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.
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Potter A, Jardine A, Neville PJ. A Survey of Knowledge, Attitudes, and Practices in Relation to Mosquitoes and Mosquito-Borne Disease in Western Australia. Front Public Health 2016; 4:32. [PMID: 26973827 PMCID: PMC4770046 DOI: 10.3389/fpubh.2016.00032] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 02/15/2016] [Indexed: 11/29/2022] Open
Abstract
On average, more than 1,000 individuals will acquire a mosquito-borne disease in Western Australia (WA) each year. Knowledge, attitudes, and practices (KAP) in relation to mosquitoes and mosquito-borne disease have not yet been investigated within Australia. A randomized telephone survey of 2,500 households across 12 regions in WA was undertaken between February and May 2014. The aim of the survey was to obtain baseline KAP data surrounding mosquitoes and mosquito-borne diseases in different regions of WA, across a range of age groups and between males and females. The results of this survey indicate that the majority of respondents are aware of the potential for mosquitoes in WA to transmit Ross River virus, while awareness of other endemic mosquito-borne diseases remains limited. Common misconceptions exist in relation to exotic mosquito-borne diseases, with respondents incorrectly identifying malaria and dengue as endemic diseases in WA. The survey also highlighted a range of important issues, such as limited awareness of the potential for backyard breeding in domestic containers, occupational exposure to mosquitoes in regions with a large employment base in the mining and resources sector, increased exposure to mosquitoes as a result of participation in outdoor recreational activities in the north of the State, and reduced awareness of mosquito-borne disease in individuals aged 18-34 years. The results of this study will be used to inform the development of a new communication strategy by the Department of Health, to further raise awareness of mosquito-borne disease in WA. The data will then provide a baseline against which to compare future survey results, facilitating the rigorous evaluation of new communication efforts.
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Affiliation(s)
- Abbey Potter
- Medical Entomology, Environmental Health Hazards Unit, Department of Health, Perth, WA, Australia
| | - Andrew Jardine
- Medical Entomology, Environmental Health Hazards Unit, Department of Health, Perth, WA, Australia
| | - Peter J. Neville
- Medical Entomology, Environmental Health Hazards Unit, Department of Health, Perth, WA, Australia
- School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia
- Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
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