Presented By

In an average year, the U.S. sees only seven human cases of the rare and severe neurologic disease Eastern equine encephalitis, or EEE. But so far this year about 30 cases have been reported nationwide, and a pair of deaths this week brings the number of 2019 EEE fatalities up to 11, highlighting continuing risks associated with the mosquito-borne illness.

On Oct. 1, Connecticut health officials announced that a person in their 60s had died from EEE, the state’s third such death this year; another person in the state remains hospitalized due to EEE, officials said. The next day, Michigan health officials announced that a fourth person in that state had died from the disease, bringing the national death count up to an estimated 11.

Here’s what to know about the rare but serious illness EEE.

What is EEE?

EEE virus is transmitted to humans by the bites of infected mosquitoes, but it cannot be spread person-to-person. Symptoms begin with headache, fever, chills and vomiting, according to the Centers for Disease Control and Prevention (CDC), and can progress in serious cases to include neurologic issues such as brain inflammation (encephalitis), disorientation, seizures and coma. About one third of those who get EEE die, the CDC says.

Where has EEE been detected?

The disease is most common in Atlantic and Gulf Coast states, though it does sometimes pop up in other regions, according to the CDC. This year, cases have been reported in Michigan, Tennessee, North Carolina, Massachusetts, Rhode Island, Connecticut and New Jersey, according to provisional estimates from the CDC. Four people have died from EEE in Michigan, three people have died in both Connecticut and Massachusetts and one person has died in Rhode Island.

When does EEE season end?

EEE cases are most commonly reported from late spring to early fall, according to the CDC—so incidence should begin to decline soon, despite the pair of recent deaths. However, the CDC warns that rare cases of the disease do occur into the winter in warmer climates, such as in the Gulf States. An unseasonably warm late summer and early fall may also extend mosquito season in some parts of the country.

Can you prevent EEE?

The best and simplest way to prevent EEE is to prevent mosquito bites by wearing insect repellent on skin and clothes; maintaining screens on doors and windows to keep mosquitoes out of indoor spaces; and avoiding letting water collect in places like flower pots, buckets and barrels, since mosquitos are drawn to standing water.

Prevention is the best medicine, since there is no specific treatment for EEE, according to the CDC.

More Must-Reads From TIME

Write to Jamie Ducharme at

You May Also Like