Health officials are reporting that a third Bexar County mosquito has tested positive for the West Nile virus. The mosquito was reportedly found near Highway 90 and Cagnon Road in southwestern San Antonio. Public Works crews are fogging and treating several parts of the county where West Nile has been discovered. The Bexar County Office of Emergency Management has visited more than 800 homes to distribute information about preventing the spread of the virus to residents and their families.