West Nile Virus in Horses

Facts About West Nile Virus in Horses

West Nile virus in horses is not very common and is usually nothing to worry about as long as early precautions are taken to treat the infected horse. Like the West Nile virus in humans, the disease is not transmittable from horse to horse or from horse to person. The only known way that a horse can become infected with the West Nile virus is by being bitten by an infected mosquito. Through the insect’s bite, the virus is injected into the horse’s blood system, multiplies, and can cause illness. West Nile virus in horses becomes dangerous only if the virus infects the brain. This can lead to brain inflammation and thereafter interfere with the normal function of the animal’s central nervous system. Once the horse’s central nervous system is seriously affected, possible death can ensue.

Symptoms of the West Nile virus in horses
Signs that could indicate that a horse is infected with the West Nile virus include: stumbling, weakness in hind limbs, inability to stand, listlessness and head shaking. However, some infected horses show no signs at all.

How should a horse with the West Nile virus be treated?
There is no reason to destroy or even isolate a horse that is infected with the West Nile virus. Most horses will fully recover from the illness. Treatment for the horse should be consistent with standard veterinary practice for animals infected with a viral disease.

Can horses be vaccinated against the West Nile virus?
The answer is yes. A vaccination against the West Nile virus for horses has recently been approved by the FDA for veterinary use only. The vaccination is called West Nile Innovator (Fort Dodge) and it helps horses develop immunity to West Nile infections. However, the effectiveness of the vaccine has yet to be determined.