Avian malaria prevalence and mosquito abundance in the Western Cape, South Africa

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dc.contributor.authorOkanga, Sharonen_ZA
dc.contributor.authorCumming, Graemeen_ZA
dc.contributor.authorHockey, Phillipen_ZA
dc.date.accessioned2015-11-27T09:30:51Z
dc.date.available2015-11-27T09:30:51Z
dc.date.issued2013en_ZA
dc.description.abstractBACKGROUND:The close relationship between vector-borne diseases and their environment is well documented, especially for diseases with water-dependent vectors such as avian malaria. Mosquitoes are the primary vectors of avian malaria and also the definitive hosts in the disease life cycle. Factors pertinent to mosquito ecology are likely to be influential to observed infection patterns; such factors include rainfall, season, temperature, and water quality. METHODS: The influence of mosquito abundance and occurrence on the prevalence of Plasmodium spp. in the Ploceidae family (weavers) was examined, taking into account factors with an indirect influence upon mosquito ecology. Mosquitoes and weaver blood samples were simultaneously collected in the Western Cape, South Africa over a two-year period, and patterns of vector abundance and infection prevalence were compared. Dissolved oxygen, pH, temperature and salinity measurements were taken at 20 permanent waterbodies. Rainfall during this period was also quantified using remotely sensed data from up to 6months prior to sampling months. RESULTS: Sixteen wetlands had weavers infected with avian malaria. More than half of the mosquitoes caught were trapped at one site; when this site was excluded, the number of mosquitoes trapped did not vary significantly between sites. The majority of mosquitoes collected belonged to the predominant vector species group for avian malaria (Culex culex species complex). Seasonal variation occurred in infection and mosquito prevalence, water pH and water temperature, with greater variability observed in summer than in winter. There was a significant correlation of infection prevalence with rainfall two months prior to sampling months. Mosquito prevalence patterns across the landscape also showed a close relationship to patterns of rainfall. Contrary to predictions, a pattern of asynchronous co-variation occurred between mosquito prevalence and infection prevalence. CONCLUSION: Overall, salinity, rainfall, and mosquito prevalence and season were the most influential vector-related factors on infection prevalence. After comparison with related studies, the tentative conclusion drawn was that patterns of asynchronous variation between malaria prevalence and mosquito abundance were concurrent with those reported in lag response patterns.en_ZA
dc.identifier.apacitationOkanga, S., Cumming, G., & Hockey, P. (2013). Avian malaria prevalence and mosquito abundance in the Western Cape, South Africa. <i>Malaria Journal</i>, http://hdl.handle.net/11427/15385en_ZA
dc.identifier.chicagocitationOkanga, Sharon, Graeme Cumming, and Phillip Hockey "Avian malaria prevalence and mosquito abundance in the Western Cape, South Africa." <i>Malaria Journal</i> (2013) http://hdl.handle.net/11427/15385en_ZA
dc.identifier.citationOkanga, S., Cumming, G. S., & Hockeyˆ, P. A. (2013). Avian malaria prevalence and mosquito abundance in the Western Cape, South Africa. Malaria journal, 12(1), 1-14.en_ZA
dc.identifier.ris TY - Journal Article AU - Okanga, Sharon AU - Cumming, Graeme AU - Hockey, Phillip AB - BACKGROUND:The close relationship between vector-borne diseases and their environment is well documented, especially for diseases with water-dependent vectors such as avian malaria. Mosquitoes are the primary vectors of avian malaria and also the definitive hosts in the disease life cycle. Factors pertinent to mosquito ecology are likely to be influential to observed infection patterns; such factors include rainfall, season, temperature, and water quality. METHODS: The influence of mosquito abundance and occurrence on the prevalence of Plasmodium spp. in the Ploceidae family (weavers) was examined, taking into account factors with an indirect influence upon mosquito ecology. Mosquitoes and weaver blood samples were simultaneously collected in the Western Cape, South Africa over a two-year period, and patterns of vector abundance and infection prevalence were compared. Dissolved oxygen, pH, temperature and salinity measurements were taken at 20 permanent waterbodies. Rainfall during this period was also quantified using remotely sensed data from up to 6months prior to sampling months. RESULTS: Sixteen wetlands had weavers infected with avian malaria. More than half of the mosquitoes caught were trapped at one site; when this site was excluded, the number of mosquitoes trapped did not vary significantly between sites. The majority of mosquitoes collected belonged to the predominant vector species group for avian malaria (Culex culex species complex). Seasonal variation occurred in infection and mosquito prevalence, water pH and water temperature, with greater variability observed in summer than in winter. There was a significant correlation of infection prevalence with rainfall two months prior to sampling months. Mosquito prevalence patterns across the landscape also showed a close relationship to patterns of rainfall. Contrary to predictions, a pattern of asynchronous co-variation occurred between mosquito prevalence and infection prevalence. CONCLUSION: Overall, salinity, rainfall, and mosquito prevalence and season were the most influential vector-related factors on infection prevalence. After comparison with related studies, the tentative conclusion drawn was that patterns of asynchronous variation between malaria prevalence and mosquito abundance were concurrent with those reported in lag response patterns. DA - 2013 DB - OpenUCT DO - 10.1186/1475-2875-12-370 DP - University of Cape Town J1 - Malaria Journal LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - Avian malaria prevalence and mosquito abundance in the Western Cape, South Africa TI - Avian malaria prevalence and mosquito abundance in the Western Cape, South Africa UR - http://hdl.handle.net/11427/15385 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/15385
dc.identifier.urihttp://dx.doi.org/10.1186/1475-2875-12-370
dc.identifier.vancouvercitationOkanga S, Cumming G, Hockey P. Avian malaria prevalence and mosquito abundance in the Western Cape, South Africa. Malaria Journal. 2013; http://hdl.handle.net/11427/15385.en_ZA
dc.language.isoengen_ZA
dc.publisherBioMed Central Ltden_ZA
dc.publisher.departmentPercy FitzPatrick Institute of African Ornithologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.rightsThis is an Open Access article distributed under the terms of the Creative Commons Attribution Licenseen_ZA
dc.rights.holder2013 Okanga et al.; licensee BioMed Central Ltd.en_ZA
dc.rights.urihttp://creativecommons.org/licenses/by/2.0en_ZA
dc.sourceMalaria Journalen_ZA
dc.source.urihttp://www.malariajournal.com/en_ZA
dc.subject.otherAvian malariaen_ZA
dc.subject.otherMosquitoen_ZA
dc.subject.otherWestern Capeen_ZA
dc.subject.otherSouth Africaen_ZA
dc.titleAvian malaria prevalence and mosquito abundance in the Western Cape, South Africaen_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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