The West Nile Virus is a flavivirus that infects the central nervous system and may cause inflammation of the brain, lining of the brain and spinal cord.
The first case of West Nile in a horse was reported in Queens, New York in 1999. Since then all but Alaska, Maine and Hawaii have reported cases of WNV.
West Nile must be inside a host to replicate. Mosquitoes infect birds, the infected birds are fed on by more mosquitoes, and those mosquitoes then feed on and infect a horse.
There are numerous symptoms of West Nile in horses. The horse may have a combination of symptoms or show none at all. It typically takes 5 to 15 days to show signs of West Nile.
The West Nile Virus can look like Eastern equine encephalitis, equine protozoal, myeloencephalitis, equine herpesvirus-1, Rabies, botulism, EPM and other neurological illnesses.
Below are the most common symptoms that may show if your horse has contracted WNV
- Lack of coordination
- Lack of appetite
- Weakness in the hind end
- Droopy lip (paralysis of lower lip)
- Disorientation, circling, or wandering
- Inability to swallow
- Muscle twitching
- Excessive sweating
- Partial or total paralysis
What should you do if you suspect the disease?
If infection is suspected, it is imperative that you have a veterinarian out as soon as possible! Your veterinarian will test to confirm that you are dealing with West Nile as many of the symptoms closely resemble other equine neurological diseases.
What will happen next?
There is not a specific treatment for West Nile. Your veterinarian will determine the best approach which may include anti-inflammatory drugs, intravenous fluids and nutritional support.
How can you help prevent the disease?
Vaccinating your horses annually is recommended.
WNV vaccine prices start at $25.95 from Big Dee’s. These are all killed virus vaccines. These are all inactive vaccines that consist of virus particles grown in culture and then killed.
Other ways to deter mosquitoes?
- Remove stagnant water sources: Empty buckets & stock tanks regularly, clean gutters, and grade areas of the field where water pools.
- Use barn safe electric fans
- Remove manure regularly and control weeds
- Keep horses in the barn during peak mosquito hours
- Fly sheets and/or fly masks
- Insect repellants that work on mosquitoes.
For more information visit the American Association of Equine Practitioners or contact your veterinarian