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Spatial and temporal dynamics of malaria transmission in rural western Kenya

Amek, N. and Bayoh, N. and Hamel, M. and Lindblade, K. A. and Gimnig, J. and Odhiambo, F. and Laserson, K. F. and Slutsker, L. and Smith, T. and Vounatsou, P.. (2012) Spatial and temporal dynamics of malaria transmission in rural western Kenya. Parasites and Vectors, 5 (86).

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Official URL: http://edoc.unibas.ch/dok/A6094383

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Abstract

ABSTRACT: BACKGROUND: Understanding the impact of reducing Plasmodium falciparum malaria transmission requires estimates of the relationship between health outcomes and exposure to infectious mosquitoes. However, measures of exposure such as mosquito density and entomological inoculation rate (EIR) are generally aggregated over large areas and time periods, biasing the outcome-exposure relationship. There are few studies examining the extent and drivers of local variation in malaria exposure in endemic areas. METHODS: We describe the spatio-temporal dynamics of malaria transmission intensity measured by mosquito density and EIR in the KEMRI/CDC health and demographic surveillance system using entomological data collected during 2002-2004. Geostatistical zero inflated binomial and negative binomial models were applied to obtain location specific (house) estimates of sporozoite rates and mosquito densities respectively. Model-based predictions were multiplied to estimate the spatial pattern of annual entomological inoculation rate, a measure of the number of infective bites a person receive per unit of time. The models included environmental and climatic predictors extracted from satellite data, harmonic seasonal trends and parameters describing space-time correlation. RESULTS: Anopheles gambiae s.l was the main vector species accounting for 86% (n=2309) of the total collected mosquitoes with the remainder being Anopheles funestus. Sixty eight percent (757/1110) of the surveyed houses had no mosquitoes. Distance to water bodies, vegetation and day temperature were significantly associated with mosquito density. Overall annual point estimates of EIR were 6.7, 9.3 and 9.6 infectious bites per annum for 2002, 2003 and 2004 respectively. Monthly mosquito density and EIR varied over the study period peaking in May during the wet season. The predicted and observed densities and EIR showed a strong seasonal and spatial pattern over the study area. CONCLUSIONS: Spatio-temporal maps of malaria transmission intensity obtained in this study are not only useful in understanding variability in malaria epidemiology over small areas but also provides a high resolution exposure surface that can be used to analyse the impact of malaria exposure on mortality
Faculties and Departments:09 Associated Institutions > Swiss Tropical and Public Health Institute (Swiss TPH) > Department of Epidemiology and Public Health (EPH) > Biostatistics
UniBasel Contributors:Vounatsou, Penelope and Smith, Thomas A.
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:BioMed Central
ISSN:1756-3305
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
Last Modified:16 Nov 2016 08:56
Deposited On:19 Jul 2013 07:43

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