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The original item was published from 10/2/2019 1:19:00 PM to 10/2/2019 1:21:14 PM.

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Health Department - News

Posted on: September 26, 2019

[ARCHIVED] Eastern Equine Encephalitis (EEE) Information

Mosquito news flash (1)

Update on EEE and aerial spraying in Washenaw County

As of Oct 2, 2019, Washtenaw County has no human or animal cases of EEE. We strongly encourage preventing mosquito bites whenever possible, but not avoiding the outdoors.

Washtenaw County Health Department has agreed to participate in the recommended aerial spraying in a small portion of northern Washtenaw County to combat spread of the potentially deadly EEE virus. The area targeted for spraying is a 2.5 mile radius around the confirmed animal case in neighboring Livingston County. This area includes parts of Livingston County, as well as northern Northfield and Webster Townships in Washtenaw County. This decision was made in collaboration with the Michigan Department of Health and Human Services (MDHHS); an aerial spray will lower the mosquito population and reduce the risk of humans or animals contracting EEE. 

This area is a weather alternative for spraying the night of Oct. 2 into the morning of Oct. 3. The Washtenaw County zone will only be sprayed tonight (Oct. 2) if, due to weather, it is not possible to spray the areas in southwest Michigan prioritized for treatment tonight. All aerial treatment will begin at dusk and conclude by 4:30 am.

Please see for updates, aerial spray schedules and detailed county spray

To date, EEE has been confirmed in nine people in Michigan, with three fatalities, in Barry, Berrien, Calhoun, Cass, Kalamazoo and Van Buren counties. In addition, cases have occurred in 33 animals from 15 counties: Allegan, Barry, Berrien, Calhoun, Cass, Genesee, Jackson, Kalamazoo, Kent, Lapeer, Livingston, Montcalm, Newaygo, St. Joseph and Van Buren. 

Residents can opt out of the recommended spraying intervention. This will reduce the overall treatment effectiveness in the area. Mosquito populations upwind of the opt-out area will not be reduced, and neighbors will not benefit from the reduction in mosquito numbers. Before exercising this option, please remember that EEE is highly deadly, and that this aerial spraying does not carry any significant risks to human health, pets or the environment. To opt out, send an email with your name and full residential address to [email protected]

What is Eastern Equine Encephalitis (EEE)?

EEE is a rare disease caused by a virus that is spread by infected mosquitoes. EEE virus is one of a group of mosquito-transmitted viruses that can cause inflammation of the brain (encephalitis). In the United States, approximately 5-10 EEE cases are reported annually. Unfortunately, multiple human and animal cases have been reported in Michigan this year. Even with the unexpected number of cases in Michigan this year, EEE infection is considered rare. As of Oct 1, no human or animal cases of EEE have been identified in Washtenaw County. 

Symptoms usually occur within 4-10 days after the infected mosquito bite. Symptoms can be severe, including sudden onset of high fever, headache, and stiff neck. EEE can cause swelling of the brain, leading to seizures, coma, or death.

The mosquitoes that can carry the EEE virus are most often found in and around hardwood forests or freshwater swamps and bogs, usually at night between dusk and dawn. Not all mosquitoes can carry the EEE virus, and only about 4-5% of human infections result in EEE illness. Individuals who are over the age of 50, under the age of 15, or have compromised immune systems due to underlying medical conditions or treatments are at elevated risk for contracting the virus.

The best way to avoid EEE is to prevent mosquito bites. 

Mosquito bite prevention tips:

  • bug sprayUse insect repellent to prevent mosquito bites. To find a repellent right for you, use the Environmental Protection Agency’s insect repellent search tool:
  • Wear long sleeves, pants, shoes, and socks when outdoors.
  • Repair screens on windows and doors to keep mosquitoes out of your home.
  • Reduce mosquito breeding conditions by eliminating standing water around your yard. Clean gutters and empty flower pots, tires, barrels, and other items that can hold water.

More information

Washtenaw County Health Department
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