Arbovirus surveillance on the Mexico-USA border: West Nile virus identification in various species of field mosquitoes

West Nile virus (WNV) has been documented in human and/or mosquito samples near the border with Mexico in El Paso, Texas, and Dona Ana County, New Mexico. However, on the Mexican side of the border, particularly in the State of Chihuahua, no such cases of WNV-infected mosquitoes have been documented. We tested 367 mosquitoes of four species (Culex quinquefasciatus, Cx. tarsalis, Aedes aegypti, and Aedes (Ochlerotatus) epactius) and found a high rate of WNV-positivity, including the first record of Ae. (Ochlerotatus) epactius infection with WNV. These results call for intensifying WNV surveillance efforts on the border between the United States and Mexico, with particular emphasis on vector control and monitoring of the species included in this study.

Automated summary

West Nile virus (WNV) has been found in human and mosquito samples near the US-Mexico border, while no infected mosquitoes have been documented on the Mexican side. A study tested 367 mosquitoes of four species and found a high rate of WNV-positivity, including the first record of Ae. (Ochlerotatus) epactius infection. These findings highlight the need for enhanced WNV surveillance, vector control, and species monitoring in the border area.