Mosquito Abundance as a Proxy to Assess Vector-Borne Disease Risk

Abstract

This work characterizes the most suitable Mediterranean environment for Culex pipiens s.l., using 7 years of data collected in Portugal from May to October each year. Culex pipiens s.l. is the most common mosquito complex with a Holarctic distribution and medical importance, being the vector of more than 20 virus species. Female mosquito abundance data is used with environmental factors in a geographic information system to characterize their habitat, using land use/cover data, distance to mapped bodies of water and altitude. The distribution of mosquitoes by each factor shows mosquito preferences and identifies thresholds between zones of higher/lower abundance for i) altitude at 100 m intervals and ii) distance to water at 1000 m intervals; in the case of land use/land cover, subsets of more/less populated classes are identified and aggregated. These thresholds allow the corresponding maps to be segmented, with their intersection being the common area where all the environmental factors considered favor the presence of mosquitoes, thus constituting areas of significant risk for disease transmission. The above-average catches of the entire data set have made it possible to identify three categories of increased risk, where countermeasures should be focused in detailed mitigation planning. This methodology can be used for any other vector of medical importance, whenever abundance data is available, helping to reduce costs, human labor and the adverse side effects of insecticide application.