We’re firmly in fall and temperatures are dropping, but the number of confirmed equine West Nile virus (WNV) and Eastern equine encephalitis (EEE) across the country is rising. Still, the case totals are lower than the number of cases reported last year in the United States.

The USDA Animal and Plant Health Inspection Service (APHIS) reported 296 WNV cases and 177 EEE cases as of Nov. 4. At the previous update (Sept. 25), the agency reported 157 WNV cases and 139 EEE cases.

According to the APHIS disease maps, equine WNV has been confirmed in 38 states thus far in 2013. Texas (39), Oklahoma (30), and Montana (27) have reported the most cases this year.

Meanwhile, 22 states in the eastern half of the country have reported EEE in horses so far this year. South Carolina (49), Florida (34), and Georgia (23) have reported the most cases, while the remaining states have all reported less than 15 cases, with most of them reporting six or fewer.

Last year, a total of 627 equine WNV cases were confirmed in horses nationwide, while 209 EEE cases were reported.

Vaccinating horses against WNV and EEE coupled with mosquito control are the most important ways to minimize an animal’s chances of becoming infected. In the northern regions of the United States, most veterinarians recommend vaccinating horses in the spring prior to peak mosquito levels. In the south, where mosquito populations are present year-round, veterinarians might recommend more frequent vaccination.

Minimizing mosquito populations near your horses by eliminating mosquito breeding and resting areas will reduce the chances these insects bite and infect horse