4/18/2023 0 Comments Vector borne transmission![]() ![]() If the characteristics of hosts most often infectious or important for transmission are known they could be targeted to more efficiently prevent disease. Understanding and describing what drives heterogeneous contact patterns is thus important for designing improved disease surveillance and prevention programs. Variation in contact patterns can amplify, or dampen the rate of transmission, even as it also potentially reduces disease prevalence and epidemic stability (i.e., likelihood of an outbreak ). Some hosts will be exposed to, harbor, and pass on more parasites than others. We outline several important considerations for designing epidemiological studies to encourage investigation of individual human movement, based on experience studying dengue.įor vector-borne pathogens heterogeneity in patterns of contact between susceptible hosts and infectious agents is common. Our analysis illustrates the importance of human movement for pathogen transmission, yet little is known-especially for populations most at risk to vector-borne diseases (e.g., dengue, leishmaniasis, etc.). An example scenario illustrates how movement generates variation in exposure risk across individuals, how transmission rates within sites can be increased, and that risk within sites is not solely determined by vector density, as is commonly assumed. We develop a model to quantify risk of vector contact across locations people visit, with emphasis on mosquito-borne dengue virus in the Amazonian city of Iquitos, Peru. We develop a conceptual framework to organize past studies by the scale of movement and then examine movements at fine-scale-i.e., people going through their regular, daily routine-that determine exposure to insect vectors for their role in the dynamics of pathogen transmission. Human movement-which determines exposure to vectors-is a key behavioral component of vector-borne disease epidemiology that is poorly understood. Vector-borne diseases constitute a largely neglected and enormous burden on public health in many resource-challenged environments, demanding efficient control strategies that could be developed through improved understanding of pathogen transmission. To encourage investigation of human movement and disease, we review methods currently available to study human movement and, based on our experience studying dengue in Peru, discuss several important questions to address when designing a study. This illustrates the importance of human movement for understanding and predicting the dynamics of a disease like dengue. For the example considered, intriguingly, our model predicts little correspondence between vector abundance in a site and estimated R 0 for that site when movement is considered. Movement also influences for which sites and individuals risk is greatest. Using a simple example, we estimate a transmission rate ( R 0) of 1.3 when exposure is assumed to occur only in the home versus 3.75 when exposure at multiple locations-e.g., market, friend's-due to movement is considered. Focusing on the day-biting Aedes aegypti, we illustrate how vector biting behavior combined with fine-scale movements of individual humans engaged in their regular daily routine can influence transmission. We develop a model showing that the relevance of human movement at a particular scale depends on vector behavior. ![]()
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