Meteorological Effects on the Abundance of West Nile Virus Mosquito Vectors in Two Communities Located on the Texas-Mexico Border in the Northern Chihuahuan Desert.

Background: Mosquitoes in the genus Culex are vectors of multiple arboviruses, including West Nile virus, St. Louis Encephalitis virus, and Western equine encephalitis virus. In the United States, West Nile (WN) is the leading cause of mosquito-borne diseases, including the El Paso, Texas, and surrounding communities. While Cx. quinquefasciatus, Cx. tarsalis, and Cx. erythrothorax are well documented in the El Paso region, the meteorological effects on the overall abundance and virus transmission risk are not well understood. Our study objective was to estimate temporal population abundance in two urban communities: Sparks, El Paso, Texas, and Anapra, Ciudad Juárez, Chihuahua, Mexico. Materials and Methods: Population abundance was estimated through collections of Cx. quinquefasciatus, Cx. tarsalis, and Cx. erythrothorax from June to December across years 2016-2018 using confirmed human case gravid traps. Mosquitoes were collected inside and outside 108 and 101 participating homes in Sparks and Anapra, respectively. Results: Generally, the results indicated that the abundance of these mosquito species was highest in June, followed by a slight decrease and then an increase in abundance during August, followed by a slight decrease until their near absence in December with colder winter season. The high abundance early in the year could be attributed to overwintering behavior which allowed these species to become dormant and/or diapause until ideal favorable environmental conditions return year after year during the spring season. Conclusion: Interestingly, the overall abundance of Cx. spp. was greater in Anapra, where no WN human cases have been reported. Our study provided a better understanding of the seasonal abundance and risk of arbovirus transmission by these medically important mosquitoes and the need to implement vector control measures early in the year.