The Oklahoma State Department of Health (OSDH) confirmed on July 7 that two horses in the southwest region of the state had tested positive for West Nile virus (WNV) The equine cases were reported in Comanche and Washita counties.

“Given the fact that we are not testing birds this year, these two equine cases are our first surveillance indicators that West Nile virus is currently circulating in Oklahoma,” said interim state epidemiologist Kristy Bradley, DVM, MPH, Dipl. ACVPM. She said the OSDH public health laboratory has not yet confirmed any human cases for the 2005 WNV season.

West Nile virus is spread primarily by the bite of an infected mosquito. The virus made its way into Oklahoma during the summer of 2002. (For more information and archived stories on WNV, visit www.TheHorse.com/wnv.)

From now until early fall, the OSDH will conduct West Nile virus surveillance activities that include mosquito trapping and testing in some communities and investigating reported cases of illness in people and horses. The OSDH will also continue to work with local communities and county health departments to direct community mosquito control interventions, such as larvicide treatment of standing water, spraying for adult mosquitoes, and collection of old tires and roadside trash