Horses Test Positive for Eastern Equine Encephalitis Virus in Wisconsin

The Wisconsin Department of Health Services (DHS) is urging everyone to continue to protect themselves from mosquito bites now that six horses in Northwestern Wisconsin have tested positive for eastern equine encephalitis (EEE), caused by the EEE virus, since late July.

EEE virus can be spread to humans, horses, and other animals through the bite of an infected mosquito. Mosquitoes acquire EEE virus by feeding on infected birds. The virus is not spread person to person or directly between animals and humans. Presence of EEE positive horses in the state confirms that there are mosquitoes in the area infected with the EEE virus that can spread the virus to people and other animals. No EEE cases in humans have been reported in Wisconsin in 2020 at this time.

Many people infected with EEE virus do not get sick. Those who do become ill may develop encephalitis (inflammation of the brain) that typically begins with the sudden development of fever, headache, chills, and vomiting. The illness may become severe resulting in disorientation, seizures, coma, or death. There is no specific treatment for EEE illness, and death occurs in approximately 30% of people who develop encephalitis from EEE.

EEE is very rare in Wisconsin with only three human cases reported in Wisconsin between 1964 and 2019. However, since the infection can be so severe, and since EEE virus is known to be circulating in Wisconsin, residents and visitors anywhere in the state should be vigilant in preventing mosquito bites.

The Wisconsin Department of Health Services offers these tips to protect yourself and your family against mosquito bites:

• Limit time spent outside at dawn and dusk, when mosquitoes are most active.
• Apply an insect repellent with DEET, IR3535, picaridin, or oil of lemon eucalyptus to exposed skin and clothes.
• Make sure window and door screens are intact to prevent mosquitoes from getting into your home.
• Prevent mosquitoes from breeding by removing stagnant water from items around your property, such as tin cans, plastic containers, flower pots, discarded tires, roof gutters, and downspouts.
• Turn over wheelbarrows, wading pools, buckets, and boats when not in use.
• Change the water in bird baths and pet dishes at least every three days.
• Clean and chlorinate swimming pools, outdoor saunas, and hot tubs; drain water from pool covers.
• Landscape to prevent water from pooling in low-lying areas, and trim tall grass, weeds, and vines since mosquitoes use these areas to rest during hot daylight hours.