Measuring Entomological Risk for Dengue

University Of California At Davis, Davis CA

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Abstract

[unreadable] DESCRIPTION (provided by applicant): The impact of human movement patterns on exposure of people to bites from mosquito vectors is a major knowledge gap in the understanding of dengue virus (DV) transmission dynamics. Because Ae. aegypti is a daytime biting mosquito we anticipate that the daytime activity patterns of human hosts will profoundly affect their risk of exposure to infective mosquito bites. Testing these ideas will require identification of operationally feasible measures of entomological risk estimated at an appropriate geographic scale that accounts for movements of susceptible humans in and out of high risk areas. Relative risk of DV infection has never been rigorously measured at the multiple locations that susceptible individual visit during their daily activities; like the homes of neighbors or relatives, schools, markets, workplaces or other communities. In the Amazonian city of Iquitos, Peru where we have over 6 years of Ae. aegypti and dengue research experience we propose to test the hypothesis that spatial dimensions of dengue virus transmission are defined by daily patterns of human movement. We predict that DV incidence rates are positively correlated with the number of bites received from Aedes aegypti at high risk locations, serotype specific herd immunity, and ambient temperature. We intend to test our hypothesis in the context of 2 specific aims. First, a combination of retrospective and prospective cohort studies will be used to determine whether measurement of entomological risk across a person's activity space provides a better prediction of DV infection risk than limiting assessment to their household. Second, we will use DNA profiling of blood in engorged mosquitoes to determine the risk of a person being bitten by Ae. aegypti at different sites across their activity space. Data collected in these field studies will be analyzed using a series of spatial statistical techniques and social network modeling to define the spatial dimensions of DV transmission and the predictive value of entomological surveillance. Our goal is to clarify the value of entomological indices in dengue surveillance programs by defining the spatial dimensions of DV transmission. Our research will be the most definitive test to-date of the empirical relationship between entomological risk and DV transmission. Our results will be relevant for dengue prevention programs based on vector control and/or vaccine strategies and will have immediate, practical applications for dengue surveillance and control worldwide. [unreadable] [unreadable] [unreadable]