West Nile Virus FAQ

What are the symptoms of West Nile Virus? How is it spread?

Symptoms of West Nile Virus include:

• Stumbling or tripping
• Muscle weakness or twitching
• Partial paralysis
• Loss of appetite
• Depression or lethargy
• Head pressing or tilt
• Impaired vision
• Wandering or circling
• Inability to swallow
• Inability to stand up
• Fever
• Convulsions
• Coma
• Death

The disease cycle starts with infected birds, which can travel long distances in a short amount of time. When a mosquito bites a bird carrying the West Nile virus, it too becomes infected. The mosquito then feeds on a horse, human or other mammal. Once a horse has been bitten, it may take only 5 to 15 days for signs of West Nile virus to appear.

What can you tell me about the vaccine?

The U.S. Department of Agriculture recently granted a conditional license to Fort Dodge Animal Health for a first West Nile virus vaccine for horses. The vaccine is labeled for vaccination of healthy horses as an aid in the prevention of disease caused by West Nile virus. The recommended dose is two 1-mL doses, three weeks apart, plus annual revaccination and is available only from a licensed veterinarian.

I use a vaccine for Western, Eastern and/or Venezuelan equine encephalitis - is my horse protected from WNV?

No. Vaccines that protect your horses against Western, Eastern and Venezuelan equine encephalitis do not protect against encephalitis caused by West Nile virus.

Besides vaccination, what can I do to decrease my horse's exposure to West Nile Virus?

You can use a fly control product designed for mosquitos. We carry dozens of products for horse and stable that are effective against mosquitoes, see our Fly and Pest Control section for a great selection of these items. More tips:

• Remove standing water from buckets, old tires and other areas where mosquitoes may breed.
• Make sure roof gutters drain properly. Clean clogged gutters in the spring and fall.
• Turn over wheelbarrows and stock tanks when not in use.
• Eliminate any standing water that collects on your property.
• Keep horses stabled during dawn and dusk, when mosquitoes are most active.
• Turn off lights that attract mosquitoes at night.
• Use fluorescent lights, which do not attract mosquitoes.
• Keep screens in stable windows.

Who else can I contact for info on the WNV vaccine, besides my vet?