West Nile Virus in Horses

With the flooding we have had this spring, the potential for West Nile Virus is a Major Concern. Now, pretty much every horse owner knows about the potential of West Nile Virus in horses but this year we are expecting to see an increase in the number of cases.

Signs of West Nile Virus include stumbling, weakness, hindlimb paralysis, muscle twitching and in some cases, death. Fever occurs in less than one-fourth of all confirmed equine cases. Each horse may exhibit a combination of symptoms or none. Once a horse has been bitten, it takes 5-15 days for signs of West Nile Virus to appear.

Treatment is very difficult as there is no specific antibody to counter the effects of the virus. Supportive therapy is a major key to the success of treatment. Recovery time depends on the health of the horses and the severity of symptoms. Horses that are unable to stand require slinging to aid in circulation and to prevent pressure sores. Horses that are unable to eat or drink may require nutritional and fluid therapy. Recent statistics show that 2/3 of horses with West Nile Virus will recover up to 17% may relapse or have incomplete recovery.  In some cases, horses will develop secondary conditions such as joint and tendon infections, pneumonia and diarrhea can all occur.

There are quite a few things that can be done to reduce the risk of West Nile Virus in your horses. First and foremost, Vaccines are highly effective to prevent the disease. It does require two vaccines given 3 weeks apart then yearly after that. Typically, we see West Nile Virus in August so giving the vaccines now will give them time to reach maximum effectiveness before then. Horses that are vaccinated before being exposed to West Nile will benefit from protection against the virus but if they do manage to contract it while vaccinated, they will have a lessened reaction and symptoms.  We do carry the vaccines so please let us know if you would like to pick some up to vaccinate your horse. We recommend that every horse be vaccinated to ensure their safety. We can also vaccinate your horses for you if that is easier for you!

Removing all unnecessary standing water including those in tires, in gutters, in buckets, and in pools is a great step. If the water can not be removed, using “mosquito dunks” or Bti granules are effective at controlling the mosquito population.  

If you have any additional questions, please feel free to call us. We will be happy to assist you with your horse health questions.

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