West Nile Virus Identification in Various Species of Field Mosquitoes on the U.S.-Mexico Border

For the past 18 years, the presence of the West Nile virus has been documented in human samples, mosquito samples, or both in El Paso, Texas, and Doña Ana County, New Mexico. In some years, the distribution of infected mosquitoes reaches other counties in both states. However, positive cases of infected mosquitoes on the border with Mexico, particularly in the State of Chihuahua, are not documented. In this work, 222 mosquitoes of different species were obtained, with a high positivity rate to West Nile Virus in the four species sampled, including the first record of Aedes ( Ochlerotatus) epactius infected with this virus. These results lead to intensified surveillance efforts for West Nile virus on the border between the USA and Mexico with particular emphasis on controlling vectors in the area and the monitoring of the species included in this study.