Eastern Equine Encephalitis Confirmed in Clare County Horse

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For immediate release: August 11, 2020

Media contacts:
     MDARD: Jessy Sielski, 517-331-1151, SielskiJ@Michigan.gov
     MDHHS: Bob Wheaton, 517-241-2112, WheatonB@Michigan.gov

Eastern Equine Encephalitis Confirmed in Clare County Horse

How to Protect Your Animals, Yourself, and Your Family

LANSING, Mich.—Today, the Michigan Department of Agriculture and Rural Development (MDARD) State Veterinarian, Dr. Nora Wineland, confirmed the first case of Eastern Equine Encephalitis (EEE) for 2020 in a two-year-old filly from Clare County, which underscores the need for both horse owners and Michigan residents to take precautions.

EEE is a zoonotic, viral disease, transmitted by mosquitoes to both animals and people. EEE is one of the most dangerous mosquito-borne diseases in the U.S., with a 90-percent fatality rate among horses that become ill and a 33-percent fatality rate among humans who become ill. Last year, Michigan experienced 50 cases of EEE in animals and a record of 10 cases in humans. The virus is typically seen in late summer to early fall each year in Michigan.

People can be infected with EEE from the bite of a mosquito carrying the virus. The disease is not spread by horse-to-horse or horse-to-human contact. In humans, signs of EEE include the sudden onset of fever, chills, and body and joint aches. EEE infection can develop into severe encephalitis, resulting in headache, disorientation, tremors, seizures, and paralysis. Permanent brain damage, coma, and death may also occur in some cases.

“In 2019, Michigan experienced the worst outbreak of EEE ever documented in the state, with 10 human cases—including 6 deaths and 50 cases in animals from 20 counties,” said Dr. Joneigh Khaldun, chief medical executive and chief deputy director for health for the Michigan Department of Health and Human Services. “Michiganders are strongly urged to take precautions to protect themselves from mosquito bites. It only takes one bite from a mosquito to transmit the virus, which can lead to severe neurologic illness, permanent disability, and sometimes death.”

“This Clare County horse was never vaccinated against EEE, and it developed signs of illness—including walking in circles, leaning to the right, and pressing her head against objects—which progressed to the horse being down on the ground with an inability to get up,” said Dr. Wineland. “Horse owners in Michigan should take extra measures to protect their animals.”

To protect your animals, measures could include the following:

  • Talking to a veterinarian about vaccinating horses against EEE.
  • Placing horses in a barn under fans (as mosquitos are not strong flyers) during peak mosquito activity from dusk to dawn.
  • Using an insect repellant on the animals that is approved for the species.
  • Eliminating standing water on the property—i.e., fill in puddles, repair eaves, and change the water in buckets and bowls at least once a day.
  • Contacting a veterinarian if a horse shows signs of the illness: mild fever and stumbling, which can progress to being down and struggling to stand.

To protect yourself and your family, here’s what you should do now:

  • Apply insect repellents that contain the active ingredient DEET, or other U.S. Environmental Protection Agency-approved products to exposed skin or clothing, and always follow the manufacturer’s directions for use.
  • Wear long-sleeved shirts and long pants when outdoors. Apply insect repellent to clothing to help prevent bites.
  • Maintain window and door screening to help keep mosquitoes outside.
  • Empty water from mosquito breeding sites around the home, such as buckets, unused children’s pools, old tires or similar sites where mosquitoes may lay eggs.
  • Use nets and/or fans over outdoor eating areas. Overall, mosquito-borne illnesses, like EEE, will continue to pose a risk to both animals and humans until late fall when nighttime temperatures consistently fall below freezing.

For more information about mosquito-borne diseases, visit Michigan.gov/emergingdiseases.