All mosquito control operations in St. Tammany Parish are evidence-based. This means that each mission is driven by inspection, trap, or complaint data. Efficient service to reduce biting rates of adult mosquitoes is reliant on the sensitive detection of where and when mosquitoes and the pathogens they transmit require treatment. In 2015, we began experimenting with mosquito traps to enhance the collection of host-seeking southern house mosquitoes and other arbovirus vectors. At that time and to this day, the CDC gravid trap is considered the “gold standard” mosquito trap for the collection of Culex quinquefasciatus and its close relative Cx. pipiens. This trap employs organically-enriched water (mimicking sewage pollutants) to attract gravid female mosquitoes to lay their eggs. This trap efficiently collects mosquitoes almost exclusively of species attracted to polluted water. Even more specifically, the CDC gravid trap primarily collects females in the egg-laying life stage only. Since most of our adult mosquito treatments require flying mosquitoes to contact airborne droplets, these treatments mostly target host-seeking mosquitoes. The specificity of the CDC gravid trap is simultaneously its best asset (limiting sorting time and occasionally more efficiently collecting arbovirus-infected mosquitoes) and its primary limitation (lack of host-seeking mosquitoes and poor representation by other vectors).
Given these limitations, we began a collaboration with Dr. Kristen Healy’s lab at LSU to compare the CDC gravid trap collections with CDC no-light CO2-baited traps. This work resulted in the publication of a research article in the Journal of Medical Entomology in May 2021. This manuscript describes how the CDC no-light CO2-baited traps collect more diverse life stages and the same number of Cx. quinquefasciatus mosquitoes while collecting many other species in the same trap. The result is a more sensitive and accurate representation of the species involved in arbovirus transmission and a better ability to assess the efficacy of adult mosquito treatments.