Horse owners in Oregon are being advised to help protect against West Nile virus by vaccinating their animals and taking steps to control mosquitoes this summer. For those who have already vaccinated their horses in the past, a booster shot will strengthen immunity.

The vaccine for horses is available through local veterinarians.

A low percentage of mosquitoes carry the virus and a low percentage of horses bitten by infected mosquitoes become ill. But a horse showing signs is a serious situation. The disease causes inflammation of the brain and about one-third of affected horses die. Symptoms include stumbling, lack of coordination, weakness in the legs, depression, muscle twitching, and death.

For questions on equine testing contact the Oregon Department of Agriculture, 503-986-4680.