The rare and potentially deadly mosquito-borne virus eastern equine encephalitis is spreading in Michigan, state health officials announced Thursday.
Six more horses now have confirmed cases of the virus, which is spread by the bite of infected mosquitoes, bringing the total to 28 horses in 11 counties and one suspected human case.
State health officials announced Tuesday that an adult from Barry County is the first suspected human case of Triple E this year. Lab tests to confirm the case are underway and are expected to be completed later this week.
Livingston County now has Triple E cases in horses, according to the Michigan Department of Health and Human Services, and will be included in an aerial mosquito-control program that is scheduled to continue Thursday night.
The other high-risk counties with cases in horses are: Barry, Clare, Ionia, Isabella, Jackson, Kent, Mecosta, Montcalm, Newaygo and Oakland.
“These additional cases of EEE in horses underscores the importance of providing aerial treatment in the affected counties,” said Dr. Joneigh Khaldun, chief medical executive and chief deputy for health at MDHHS. “There is an ongoing threat to the health and safety of Michiganders as we know mosquitoes are carrying this potentially deadly disease in these areas. Last year, 10 families were devastated by this disease and we are trying to protect others from being infected.”
Eastern equine encephalitis, also called Triple E or EEE, is one of the deadliest mosquito-borne viruses in the United States. It kills 33% of people who become sickened by it. And it leaves many survivors with physical and mental disabilities.
Mosquitoes are carriers of EEE, and can transmit it to humans and animals after biting infected birds.
As of Sept. 9, five other human cases of EEE have been reported in two other states – Massachusetts and Wisconsin, according to the U.S. Centers for Disease Control and Prevention.
Last year, the virus sickened 38 people in the U.S. – more than in any previous year since it’s been tracked by the CDC. Of them, more than one-quarter – 10 people – were from Michigan.
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In a typical year, there are seven cases nationally.
Of the 10 Michigan cases in 2019, six people died, and four others were hospitalized. Three of the four people who survived EEE infections in the state “have severe neurologic issues and continue to receive supportive care, either in rehab or at home with home care,” said Lynn Sutfin, a spokeswoman for the Michigan Department of Health and Human Services.
Not all who are bitten by an EEE-infected mosquito will be sickened by the virus. Many people will have mild symptoms or no symptoms at all. The people most at risk from being sickened by EEE are those younger than 15 and older than 50.
There is no treatment for the EEE virus, except to offer support to help a severely ill patient with breathing, hydration and nutrition.
Symptoms of EEE typically appear from four to 10 days after the bite of an infected mosquito, according to the CDC. The infection can be either systemic or encephalitic, which involves the swelling of the brain. Some people who contract EEE do not have symptoms at all.
In those who develop a systemic infection, symptoms can appear suddenly and last up to two weeks. They include:
In people who develop the encephalitic infection, the following symptoms typically follow after a few days of systemic illness:
Anyone with any of those symptoms should seek care from a physician.
The only way to protect yourself from the Triple E virus is to avoid being bitten by mosquitoes.
Although the weather is beginning to cool down, the mosquitoes that spread EEE are still active. For that reason, health officials are urging people who live in the 10 affected counties to avoid outdoor activity in the evenings and after dark, when mosquitoes are most active. They suggest canceling outdoor events, especially those that might include children.