West Nile virus and Horses
Horses are affected by West Nile virus (WNV) much more often than any other domestic animals. Many horses infected with WNV do not develop any illness, but of horses that become ill, about 30 percent die or need to be euthanized. Other livestock and poultry do not commonly show any illness if infected with WNV.

Since mosquitoes are linked with WNV transmission, you can prevent or control future WNV outbreaks among horses by controlling mosquito populations and preventing horses from being exposed to any adult mosquitoes present. Similar recommendations would apply for other livestock or poultry should illness due to WNV in those types of animals ever come to be recognized.

For more information on WNV prevention and control in equine and other livestock, visit the United States Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) West Nile Virus website at
http://www.aphis.usda.gov/lpa/issues/wnv/wnv.html.

For information on submitting horse samples for testing in Wyoming, visit the website for the Wyoming State Veterinary Laboratory at
http://wyovet.uwyo.edu/.

A vaccine for horses is available. Please contact your veterinarian for more information.