Prevent Incurable Horse Virus

Image of a mosquito biting a horse.

Eastern equine encephalitis virus (EEEV) is transmitted by the bite of an infected mosquito, advises the Centers for Disease Control (CDC). The virus is rare and causes inflammation of the brain called encephalitis. Animals, especially horses, are vulnerable to this infection.

"All equine cases are the result of mosquitoes which have fed on infected birds and then feed on unvaccinated horses, " advises Wayne Crans, Entomology Research Professor in Questions Regarding Eastern Equine Encephalitis and Horses. Horses are increasingly susceptible to the EEEV infection. The virus involved attacks the horse's central nervous system. "Onset is abrupt and horse cases are almost always fatal," he says.

Symptoms evident in horses infected with the virus include marked loss of coordination, unsteadiness and erratic behavior. Other signs to be aware of in horses are loss of appetite, drooping eyelids and lower lip, depression, blindness, aimless wandering and circling, and occasional paralysis. The treatment that may be provided by your veterinarian or emergency animal hospital is typically ineffective. Crans reports that after the first indications of illness in an animal "seizures resulting in death usually occur within 48 to 72 hours."

"The greater the number of infected mosquitoes, the greater the risk," says Dr. Alfred DeMaria, Wisconsin's top disease tracker," so preventing mosquito bites becomes even more important." Protecting yourself and your horse can be enhanced by following the suggestions made by the CDC and the Wisconsin Department of Agriculture, Trade and Consumer Protection.

? Provide nighttime shelter for horses from hungry mosquitoes by housing them in a barn.
? Wash out horse troughs frequently to reduce the breeding of mosquitoes near paddock areas.
? Eliminate sources of standing water.
? Wear protective clothing.
? Use insect repellent on exposed skin or clothing when outdoors especially those that contain DEET, picaridin, IR3535 or oil of lemon eucalyptus.
? Reduce or avoid outdoor activities between dusk and dawn when mosquitoes are most active.

Crans urges that vaccinations be provided to horses by only licensed veterinarians to ensure that their protection is effective. Infected horses are often found to have been "improperly vaccinated or (were) vaccinated with vaccine that had lost its protective properties."

The vaccinations when properly given are only effective for one year. Annual booster shots are required. Animals receiving their first vaccination will require a two-shot series to guarantee that their protection is adequate.

Humans that are infected with EEEV may not have any apparent illness or symptoms. Cases that are classified as severe "begin with the sudden onset of headache, high fever, chills, and vomiting. The illness may then progress into disorientation, seizures, or coma." These severe cases involve an inflammatory condition of the brain called encephalitis advises the CDC.

Sources:

Boston Globe. Massachusetts health officials raise risk level for EEE.

Center for Disease Control.

Crans, Wayne J. Questions regarding eastern equine encephalitis and horses. Rutgers Cooperative Extension Fact Sheet # FS737.

Merck Veterinary Manual.

Location

Find us on the map

Office Hours

Our Regular Schedule

Monday:

8:00 am-5:00 pm

Tuesday:

8:00 am-5:00 pm

Wednesday:

8:00 am-5:00 pm

Thursday:

8:00 am-5:00 pm

Friday:

8:00 am-5:00 pm

Saturday:

9:00 am-2:00 pm

Sunday:

--

Testimonials

Read What Our Clients Say

  • "Kath, thank you so much for being Greyson's vet, your gentle hand, compassion and great skill made all the difference for my buddy."
    --Deirdre Dekking, Portland
  • "Dr. Mertens is a very friendly, knowledgeable equine veterinarian (and a friend to the rest of the farmyard, including the chickens!). Always up to date on the latest in equine health, and even though Mertens Mammals is a small clinic giving you the personable experience, Dr. Mertens also has equipment for more advanced diagnostics and procedures!"
    —Ari Gordon, Boring
  • "I have been a client of Mertens Mammals for 10 years. Kath (Dr. Mertens) is the most kind, thoughtful and caring Vet I have ever had for my animals. I have 3 horses: my Appy "Breeze" who turns 30 this year, my Paint " Rocket " 14 and my other Paint "Fergie " 3 are all under Kath's care. I also had a dog "Cowboy" who I lost to cancer last July. Kath took care of him also. Dr.Mertens came out on Mother's Day about 7 years ago to treat Breeze for a cut above her right eye. After a few weeks of recovery we were happy to not have a huge scar. Kath also spent 2 hours with me 3 years ago when Rocket had a small case of colic. (Thank God). I couldn't ask for a better person to take care of my girls. Kath always calls to check in on the patients. When people ask who I use for my veterinary needs for my horses, I'm always proud to refer them to Mertens Mammals. I am so thankful for an honest and caring Vet. Thank you, Kath!"
    --Michelle Schatz, Portland
  • "I got looking at Sassy’s records and it will be 6 years in July when you first met Sassy—I feel so fortunate that you became her vet and have looked after her all these years. You are such a wonderful and caring doc and I know you always have Sassy’s best interests at heart. I also know I can always rely on you to help me or Sassy when needed. Thanks for all you do for both of us—will keep you posted on Sassy.”"
    —Judy Becker, Eagle Creek
  • "My horse, Pester, would have lost her eye had it not been for the great care and dedication by Mertens Mammals. They are truly there for you any time you need them. I could go on and on. Kath Mertens has been so good to us!"
    --Troy and Wendy Mohr, Estacada
  • "She has always been there for us. She is forever in my thoughts as the best vet. She saved our hours old filly from certain death. She knew exactly what to do in an instant after just seconds in seeing her. We are forever in your debt...thank you!"
    Barbara T.
  • "Thank you Dr Mertens for such a thoughtful and careful job with our sweet Daisy the Donkey this morning! She is well on her way to health again after that abscess!"
    Suzi C.