The variable contribution of larval habitats on the production of mosquitoes that transmit West Nile Virus: a landscape epidemiology approach

Many factors influence mosquito reproduction and abundance, including weather, landscape types, and habitat availability. Much of the focus of public health actions related to the reduction of mosquito-borne pathogens is on the reduction of mosquito populations through treatment or elimination of larval habitats associated with vector mosquitoes. West Nile virus is an important pathogen in North America. The objective of this study was to determine influences on Culex adult and larval mosquito population. Data for this study were collected during the summer of 2014 in a study region in suburban Chicago, Illinois. The data included a full identification of catch basin and natural standing water larval sites, weekly mosquito collections of larval and adult mosquitoes during an 18-week period, a more limited assessment of larval sites associated with containers near homes, and lawn watering activities. The analyses undertaken revealed that urban catch basins that have a higher percentage of vegetation of at least 3 meters can be expected to have more vector mosquito larvae; also warmer temperatures and less rainfall in a given week and the week prior will result in higher numbers of larvae during that week. Cemeteries in the study region tended to have more larvae in catch basins than either residential or industrial areas. One part of the study region had a spatial and temporal correlation between larval mosquitoes and adult mosquitoes, but other places had high adult abundance without a clear indication of the larval habitat contributing to that increase. It is important to consider multiple types of mosquito larval habitat, and while catch basins are an important breeding site, they are not the only source of adult mosquitoes in the region