PARENT SESSION
Poster Session 36: Genetics / Population Ecology
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Spatial dynamics of a mosquito-borne infection in a neotropical heterogeneous environment.
Grillet, Maria1, Barrera, Roberto2, Martínez, Juan1, León, Napoleón1, Aguilar, Victor1, Rangel, Gabriela1, 1 Universidad Central de Venezuela. Apartado 47072., Caracas, Venezuela2 Center for Diseases Control and Prevention, CDC., San Juan, Puerto Rico
ABSTRACT- The present work explored the effect of local spatial heterogeneity on the spread of a mosquito-borne infection and its persistence in space and time in neotropical conditions. First, we investigated, at small and large scale, the spatial structure of Plasmodium vivax infections in a small community of 30 villages in an endemic/epidemic malaria area in northeastern Venezuela by using geostatistical methods and landscape ecology. We hypothesized that malaria is a complex of many local diseases rather than a single entity, thus we stratified the villages in terms of infection persistence as the main criteria of identifying hot spots (local, high transmission foci). Second, we tested the cities and villages model that explore the effect of population size and density, as well as geographic distance, on the metapopulation dynamics of infectious diseases. Third, GIS-based processes and multivariate statistics were employed to link spatially significant epidemiologic and ecological risk factors with disease data. Findings indicated that out of 30 localities, only seven were considered hot spots. Time series analysis showed that malaria initially arrived in urban localities (hot spots), and then (up to 2 month later) spread to surrounding rural areas. Both population density as geographical distance between villages are implicated in the persistence of malaria within the study area. A strong spatial contagion pattern of infection up to a distance of approximately 10 Km and a large-scale spatial trend of malaria cases were observed, with cluster of infections localized in dense urban villages localized at low elevations, gentle slopes, and very close (< 1.5 Km) to wetlands areas (mosquito breeding sites). Our study suggest that persistence of malaria infections in this neotropical area is maintained in complex structure forming distinct patches linked by dispersal.
Key words: mosquito-borne infection, metapopulation dynamics, geostatistical models, landscape ecology