The EEE virus is spreading in the US
The mosquito strikes again


A mosquito-borne virus is making a comeback: Eastern equine encephalitis (EEE). While not actually new, cases are extremely rare. Nonetheless, there have been higher instances than usual in the U.S. this year. If a case is severe, it has the potential to be deadly, and there is no cure or prevention for the disease. Illnesses like EEE are only going to become more common as the climate continues to warm.
What is EEE?
EEE has been spreading across the northeastern U.S. The virus is spread through mosquitos but is rare and deadlier than the West Nile virus. "Approximately 30% of people who develop severe eastern equine encephalitis die, and many survivors have ongoing neurologic problems," said the Centers for Disease Control and Prevention. "Definitely, I'd say New England and the Gulf Coast are the two areas in the U.S. where it's mainly occurred in the past," David Hamer, a professor of global health and medicine at the Boston University School of Public Health, said to The Hill. "Massachusetts has had hundreds of cases over a 70-year period," Hamer added. "There may not be any for a couple years, and then there's another case or two, although we believe that it may be occurring a little more frequently."
The good news is that most people do not experience symptoms. "In 95% of cases, the infection has no symptoms at all, and the person is really quite well and doesn't know they have the virus," Ruanne Barnabas, the chief of the Division of Infectious Diseases at Massachusetts General Hospital, said to The Hill. However, the virus creates a bad situation for people who do experience symptoms. "In 5% of cases, people do have symptoms, including fever and chills. And then it can actually affect the central nervous system, and they can develop confusion, abnormal movements and encephalitis as well." In the worst cases, EEE can lead to death. The disease also has no vaccines or medicines to prevent or treat it. Instead, people should protect themselves from mosquito bites by using insect repellant and wearing long sleeves.
The Week
Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.

Sign up for The Week's Free Newsletters
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
Will EEE get worse?
Along with people, the disease has also appeared in animals including horses, llamas and alpacas. Approximately 90% of horses infected with EEE have died. Dogs and cats are at much lower risk. The disease is not transmissible between animals and can only be passed through mosquitos in both humans and animals. It is also difficult to determine who is most at risk for severe EEE. "If you look at the cases, it seems to hit, you know, young teenagers, 30-year-olds, 40-year-olds — I mean healthy people that don't have clear risk factors. And so, I think everybody needs to be cautious," Hamer said.
The growing prevalence of mosquito-borne illnesses is largely due to climate change. Mosquitos thrive in warmer temperatures, and their range is rapidly expanding. Diseases like EEE are also appearing in regions where the diseases were not present before. "We've got milder winters, we've got warmer summers and we've got extremes in both precipitation and drought," Theodore G. Andreadis, a researcher who studied mosquito-borne diseases at the Connecticut Agricultural Experiment Station, said to Grist. "The impact that this has on mosquito populations is probably quite profound."
A free daily email with the biggest news stories of the day – and the best features from TheWeek.com
Devika Rao has worked as a staff writer at The Week since 2022, covering science, the environment, climate and business. She previously worked as a policy associate for a nonprofit organization advocating for environmental action from a business perspective.
-
September 1 editorial cartoons
Cartoons Monday’s political cartoons include Labor Day picnic, branding strategy, and more
-
What is Tony Blair's plan for Gaza?
Today's Big Question Former PM has reportedly been putting together a post-war strategy 'for the past several months'
-
When does autumn begin?
The Explainer The UK is experiencing a 'false autumn', as climate change shifts seasonal weather patterns
-
Scientists are speeding up evolution
Under the radar Proteins can evolve in minutes
-
Sloth fever shows no signs of slowing down
The explainer The vector-borne illness is expanding its range
-
A new subtype of diabetes was found and it may require different treatment
Under the radar It is prevalent in Black Africans and Americans
-
Texas declares end to measles outbreak
Speed Read The vaccine-preventable disease is still spreading in neighboring states, Mexico and Canada
-
How China is battling the chikungunya virus
Under The Radar Thousands of cases of the debilitating disease have been found in the country
-
RFK Jr. shuts down mRNA vaccine funding at agency
Speed Read The decision canceled or modified 22 projects, primarily for work on vaccines and therapeutics for respiratory viruses
-
Forever chemicals were found in reusable menstrual products. That is nothing new for women.
Under the Radar Toxic chemicals are all too common in such products
-
Scientists are developing artificial blood for use in emergencies
Under the radar It could aid in global blood shortages