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BREAKING NEWS: Calumet County horse contracts EEE and has to be euthanized

Posted at 2:45 p.m. on Friday, August 20, 2021

The Brillion News

CHILTON – A horse in Calumet County in a private facility, diagnosed as being infected with deadly Eastern Equine Encephalitis (EEE), has been put down.

The three-year old Pony of the Americas mare showed signs of the disease on August 12.

Among the symptoms were head pressing, lack of an appetite, neurological indications. refusing to drink and recumbence.

EEE was confirmed on August 16, and the horse was euthanized. In most cases, from first symptoms to death is less than three days.

The Calumet County case was the third EEE case reported in Wisconsin this year.

The fourth, diagnosed on August 9, was on a farm in Marquette County, where the victim was a Percheron.

The two others were on August 11 in Monroe County and on August 17 in Burnett County.


According to the state Division of Agriculture, symptoms of encephalitis in horses include depression, loss of appetite, drooping eyelids and lower lip, fever, weakness, twitching, paralysis or lack of coordination, aimless wandering, circling, and blindness.

Horses may also go down, be unable to rise, exhibit seizures, or become unresponsive. Equine owners should contact their veterinarian if they observe any of these signs.

EEE is fatal in more than 90 percent of equine cases. In 2020, Wisconsin confirmed 26 cases of EEE.


The disease is not contagious from one horse to another and, while humans can be infected by EEE, the viruses do not pass directly between horses and people.

Mosquitoes carry the viruses from infected birds, and the only route of transmission is from a mosquito bite.

Confirmation of a horse infected with EEE means the virus is in Wisconsin's mosquito population.

Because the viruses follow mosquito populations, the threat in Wisconsin varies depending on the weather but normally starts in mid to late summer and remains until the first killing frost.

Besides vaccination, limiting exposure to mosquitoes will help control EEE and other equine diseases.

Protect your horses

The Equine Disease Communication Center ( notes that infected horses pose no risk of infection to other horses.

The EDCC recommends taking precautions to prevent mosquitoes from giving the disease to your horses:

  • Keep all horses up to date on vaccinations. Initial vaccination is followed in 4 to 6 weeks with a booster; yearly re-vaccination is recommended.

  • Use insect repellents frequently; re-apply after rain.

  • Keep horses in at night when possible, and apply insect repellent.

  • Eliminate or minimize standing water.

  • Stock your water tanks or ponds with fish that feed on mosquito larvae. (Goldfish, bass, guppies, minnows, bluegill and catfish are all fish that eat mosquito larvae. By consuming the mosquito larvae, these fish disrupt the mosquitoes’ life cycle and control their population by preventing them from becoming breeding adults.)

  • Eliminate brush piles, gutters, old tires and litter.

  • Remove all equipment in which standing water can collect.


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