1st Case of Mosquito-Borne EEE Virus Found in Rhode Island in 2024, Officials Warn

EEE is a potentially rare but fatal disease, with around 30 percent people dying from the virus, officials say.

This close-up photograph shows a mosquito in Montlouis-sur-Loire, central France, on October 21, 2022. Guillaume Souvant/AFP via Getty Images

Officials in Rhode Island on Wednesday confirmed the first case of mosquito-borne eastern equine encephalitis (EEE) this year, after neighboring Massachusetts sent out warnings over the virus.

The EEE case in Rhode Island is the state’s first human since 2019 and 11th since the early 1980s, the state’s Department of Health confirmed in a news release. The person who contracted the virus is located in Providence County and in their 70s.

“We are seeing more human cases of mosquito-borne disease in Rhode Island and in bordering communities in Massachusetts and Connecticut,” said Rhode Island Health Director Jerome Larkin in the release.

He called on residents to “continue protecting themselves from getting mosquito bites” such as avoiding outdoor activity at sunset and sunrise, wearing long-sleeved shirts and pants, and inspect repellent with DEET, or diethyltoluamide, or a similar type.

EEE is a potentially fatal disease, with around 30 percent people dying from the virus, according to the U.S. Centers for Disease Control and Prevention (CDC). However, researchers, in a paper published with the the U.S. National Library of Medicine, said that the fatality rate could be as high as 41 percent, with 50 percent suffering “long-term neurological” consequences.

The confirmation comes as officials in Massachusetts confirmed a fourth case in the state earlier this week, occurring in Middlesex County in a man in his 50s, according to a news release by the state’s Department of Public Health.

A similar warning was issued by the state’s public health commissioner, Robbie Goldstein, who said that the 2024 EEE season has been “particularly active,” triggering concerns in areas across the state.

“While EEE remains a rare disease, the risk level is elevated in multiple communities. With the weather forecast showing warm, sunny weather for the rest of the week, we recommend that people take necessary precautions in areas of elevated risk,” he said. “This includes recommending that residents and towns in areas at high risk for EEE reschedule their evening outdoor events to avoid peak mosquito biting hours from dusk to dawn.”

The state, he said, has found 91 EEE-positive samples in mosquitoes across the state this year, adding that most of the activity is located in Worcester and Plymouth counties. But EEE-infected mosquitoes have been located in Middlesex, Essex, and Bristol counties, the department said.

In late August, Massachusetts announced it would start the “aerial spraying” towns in several counties over the EEE-infected mosquitoes. The state health agency announced the first human EEE virus infection in Massachusetts for the year, occurring on Aug. 16 in Worcester County.

Officials said last month that the first infected person had often recounted to his family how he never got bitten by mosquitoes. But just before he became symptomatic, he told them he had been bitten.

EEE can cause severe disease and possibly lead to death in all age groups, but people under age 15 and people over the age of 50 are at the most risk, health officials added. An EEE outbreak in Massachusetts occurred in 2019 and 2020, with 17 people infected and seven deaths, officials said.

There have been three cases of eastern equine encephalitis in the United States this year, according to the CDC, one each in Massachusetts, New Jersey, and Vermont. The worst year for the disease was 2019, with 38 cases. It’s caused by a virus and is not very common around the world. The virus typically spreads in certain swamps, including red maple and white cedar swamps in Massachusetts.

Symptoms include fever, headache, vomiting, diarrhea, and seizures, according to the CDC. There are no vaccines or treatments for EEE.

Aside from EEE, Rhode Island officials also confirmed the state’s second case of West Nile virus, also spread by mosquitoes.