Environmental and socio-economic determinants of mosquito vector species presence and abundance in Los Angeles County, California

Abstract

Los Angeles County, California, is one of the areas most affected by arboviruses in the continental United States, reporting the second highest number of West Nile human cases in the nation and one of the highest numbers of imported dengue cases. Culex quinquefasciatus and Aedes aegypti are primary vectors of West Nile and dengue viruses, respectively. Both species are present and abundant in Los Angeles County, creating fertile grounds for arbovirus outbreaks. In this study, we aim to provide a comprehensive assessment of environmental and socio-economic features associated with the presence and abundance of Ae. aegypti and Cx. quinquefasciatus in Los Angeles County, California. To explore these associations, we leveraged mosquito surveillance data at fine spatial resolution that comprises 1,652 observations for 171 traps. We performed a Principal Component Analysis to reduce the dimensionality of the environmental and socio-economic data and developed a zero-inflated negative binomial model. Our results show that the presence of Cx. quinquefasciatus and Ae. aegypti in Los Angeles County is not associated with temperature, while it is associated with component identifying younger, more Hispanic, poorer, densely populated areas with less vegetation. The association with vegetation is particularly important for Ae. aegypti. On the other hand, when mosquito species are present, their abundance is significantly associated with temperature and differs by the month of the year. Moreover, the abundance of Cx. quinquefasciatus is negatively associated with components identifying areas with higher income, more home-value inequality, larger shares of both older and younger population, and lower vegetation; on the other hand, the relative abundance of Ae. aegypti is negatively associated with vegetation and presence of surface water. Our study provides valuable insights into the environmental and socio-economic characteristics allowing the proliferation of Cx. quinquefasciatus and Ae. aegypti. Enhancing mosquito surveillance and control in areas where these joint distributions of identified characteristics create suitable conditions for mosquito proliferation could improve arbovirus outbreak preparedness and response, as well as promote health equity.

Forecasting the relative abundance of Aedes vector populations to enhance situational awareness for mosquito control operations

“…It is important to stress that previous efforts were successfully made into esVmaVng mosquito presence and (relaVve) abundance based on environmental (e.g., temperature, rainfall, vegetaVon) and socio-economic (e.g., income, populaVon density) variables [20][21][22][23][24][25][26][27] as well as mosquito surveillance data 21,23,27 . Such approaches provide criVcal informaVon for esVmaVng the determinants of the transmission risk and dynamics of mosquito-borne diseases.…”