West Nile virus is once again being diagnosed frequently in both people and horses. According to the Center for Disease Control (CDC), the West Nile virus has been isolated in people, birds and mosquitoes in 48 states with the majority of cases coming from Texas, South Dakota, Mississippi, Oklahoma, Louisiana, and Michigan.
West Nile virus can infect horses as well as people. Horses can become infected with the disease through the bite of an infected mosquito in much the same way that people become infected.
There is currently no evidence to suggest that West Nile virus disease can be spread from horse to horse or from horses to people.
Symptoms of West Nile Virus Disease
In most cases, West Nile virus causes a mild and self-limiting disease in horses. The most commonly seen symptoms are mild fever, lethargy and lack of appetite. Most infected horses recover fully from the disease.
However, in some cases, the disease can become much more severe. Neurological symptoms such as general weakness, weakness or paralysis of the hind quarters, loss of vision or impaired vision, head pressing, circling, wandering aimlessly, seizures, difficulty swallowing, and coma can occur. The disease can be fatal for infected horses.
Treatment of Infected Horses
There is no specific cure for West Nile virus disease. As with any viral infection, treatment is supportive in nature.
There is currently a vaccine available for West Nile virus in horses. Consult your veterinarian to discuss whether your horse is at risk and whether the vaccine is recommended. Vaccinations against eastern equine encephalitis (EEE), western equine encephalitis (WEE), and Venezuelan equine encephalitis (VEE) will not protect your horse against West Nile virus as the virus belongs to a different family of viruses.
Here are some other precautions to take to help prevent infection with West Nile virus.
- Mosquitoes are most active at dusk and dawn. Keeping your horse stabled during these times will help prevent exposure to mosquitoes.
- If possible, eliminate standing/stagnant bodies of water near your horses.
- Use protective gear such as fly sheets to keep mosquitoes away from your horse.
- Apply mosquito repellents approved for use on horses.
- Place incandescent light bulbs in areas away from stalls to lure mosquitoes away.
- Fans can also help deter mosquitoes. Use fans in and around stall areas.
- Mosquitoes become infected through contact with birds. Remove any dead birds from your property. Consider contacting your local and/or state health department for help in dealing with dead birds and determining whether the bird is infected with West Nile virus.
More information about West Nile virus is provided through Pennsylvania’s West Nile Virus Control Program site.