Michigan health officials are urging residents of 11 counties to stay inside from dusk to dawn to avoid getting bitten by mosquitoes carrying a deadly virus that last year killed six people in the state.
The state Department of Health and Human Services announced Tuesday that a resident in Barry County in southwest Michigan was the state's first suspected human case of eastern equine encephalitis, called EEE.
That suspected case in a person comes after the virus has been found in 28 horses in 11 counties — twice as many animal cases as at the same time last year.
"When there are high rates of animal infections, humans are just as at risk," a state advisory said.
The health department has also urged the rescheduling or cancellation of outdoor activities during or after dusk, particularly for children.
"EEE is one of the most dangerous mosquito-borne diseases in the United States," a state advisory said, noting that people can be infected from one bite of a mosquito carrying the virus and that people younger than 15 and over 50 are at greatest risk of severe disease following infection.
“This suspected EEE case in a Michigan resident shows this is an ongoing threat to the health and safety of Michiganders and calls for continued actions to prevent exposure, including aerial treatment,” Dr. Joneigh Khaldun, chief medical executive for the MDHHS, said in a statement.
A first night of aerial anti-mosquito treatments was conducted Wednesday for high-risk areas.
As of Sept. 9, the U.S. has had only five confirmed human cases of EEE this year, three in Massachusetts and two in Wisconsin, according to the Centers for Disease Control and Prevention.
Only about 4 to 5 percent of people who become infected with the EEE virus contract encephalitis, and the U.S. has on average 11 cases of the disease each year.
But 2019 had the highest number of cases in more than a decade — 38. Michigan, with 10 cases, accounted for more than 25 percent of that number.
Signs of EEE infection include the sudden onset of fever, chills, body and joint aches, which can progress to a severe encephalitis, resulting in headache, disorientation, tremors, seizures and paralysis, the Michigan Health Department said. Approximately a third of all people with encephalitis due to EEE infection die, according to the CDC.
The best prevention is to avoid mosquito bites by following preventative measures, including using an EPA-approved mosquito repellent, wearing long sleeves and pants, and cleaning any outdoor items containing standing water, like bird baths or planters.
This article was originally published on NBCNews.com.