A horse from Van Buren County has tested positive for a virus that is transmitted through the bite of an infected mosquito.
Michigan officials said the horse, a standardbred filly, is the first domestic animal in Michigan to test positive for Eastern Equine Encephalitis (EEE) in 2024. The horse was not vaccinated.
“While this is the first case of EEE detected this season, other mosquito-borne diseases have been discovered throughout Michigan, including one human case of West Nile virus,” said State Veterinarian Dr. Nora Wineland, DVM, MS, DACVPM. “These detections clearly indicate disease is circulating in the state’s mosquito population, making it crucial to protect animals and people against these insects. Preventing mosquito bites will prevent mosquito-borne diseases.”
This is the only detection of EEE in Michigan. If you believe your animal has EEE or West Nile virus, there is funding available under an arbovirus grant to cover testing costs. You should contact MDARD at 800-292-3939.
So far this year, West Nile virus has been detected in 48 mosquito pools, 12 wild birds, and one human.
---> Let’s talk about Michigan mosquitoes: Are they eating you alive? Here’s what to know
What is EEE?
EEE is a viral disease that is transmitted through the bites of mosquitoes. Only a few human cases are reported in the United States each year, according to the CDC. In Michigan, cases are usually seen in the late summer to early fall each year.
Can humans get EEE?
Yes. However, horses do not spread the virus to other horses and horses do not spread the virus to humans.
EEE is spread through the bite of an infected mosquito and can make a human very ill.
“It only takes one bite from an infected mosquito to cause a severe illness,” said Dr. Natasha Bagdasarian, MDHHS chief medical executive. “We urge Michiganders to take precautions such as using an EPA-registered insect repellent when outdoors, avoiding areas where mosquitoes are present if possible, and wearing clothing to cover arms and legs to prevent bites. EEE is one of the most dangerous mosquito-borne diseases in the United States, with a 33% fatality rate in people who become ill.”
What are the symptoms of EEE in humans?
Most people infected with EEE do not develop symptoms. When people do develop symptoms, it usually takes between four to 10 days for the symptoms to appear. EEE can cause febrile illness or neurologic disease.
Febrile illness symptoms include fever, chills, body aches, and joint pain. The illness lasts one to two weeks and most people recover completely when the central nervous system isn’t involved.
Neurologic disease can include meningitis or encephalitis. Symptoms of neurologic disease include fever, headache, vomiting, diarrhea, seizures, behavioral changes, drowsiness, and coma. In infants, neurologic disease usually occurs soon after onset of symptoms. In older children and adults, encephalitis might occur after several days of systemic illness.
How to protect your horses, other domestic animals
- Talking to a veterinarian about vaccinating horses against EEE
- Placing livestock in a barn under fans (as mosquitos are not strong flyers) during peak mosquito activity from dusk to dawn
- Using an insect repellent on an animal that is approved for the species
- Eliminating standing water on the property
- Contacting a veterinarian if an animal shows signs of the illness: fever and stumbling, which can progress to being down and struggling to stand
Protect yourself, your family
- Apply insect repellents that contain the active ingredient DEET to exposed skin or clothing and always follow the manufacturer’s directions for use
- Wear long-sleeved shirts and long pants when outdoors
- 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
More information about EEE is available at michigan.gov/emergingdiseases.