Mosquitoes and Disease Concerns

Mosquitoes can cause health problems. Female mosquitoes feed on blood and some species can transmit certain viruses and other disease-causing pathogens to people and animals. West Nile virus (WNV) is currently the most common mosquito-borne virus causing West Nile Fever in all continental U.S. states. St. Louis encephalitis virus (SLEV) is also a concern for residents in Southwestern states. Arizona, California, and Texas have human cases of St. Louis encephalitis most years. WNV and SLEV generally cause disease in birds and are transmitted between birds by Culex mosquitoes.