What You Should Know About the Mosquito-Borne EEE Virus

It’s very rare in humans, but there are steps you can take to protect yourself

EEE virus borne by mosquitoes

If you’ve read or watched the news lately, you may have heard warnings about a rare but dangerous virus called Eastern Equine Encephalitis that’s hitting certain parts of the country harder than usual.

Advertising Policy

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

More than a dozen people have been sickened by EEE — or “triple E” — so far this year, according to data from the Centers for Disease Control and Prevention. Typically, only 5 to 10 human cases are reported to the CDC each year.

EEE is an arbovirus, which means it’s spread by mosquitoes (similar to West Nile or Zika), that can cause a severe, sometimes-deadly infection in the brain.

Though it’s dangerous, it’s also important to remember that the infection is still extremely rare in people, says neurological infectious disease specialist Adarsh Bhimraj, MD.

“This virus generally doesn’t want to be in humans because we are dead-end hosts, meaning we don’t develop enough of the virus circulating in our blood to pass it on,” he says.

As mosquito season carries on, here’s what you should keep in mind.

Advertising Policy

What is EEE virus?

EEE is not common in humans because it’s mostly passed between birds and a certain type of mosquito that feeds on birds.

But, it can be transferred to mammals, such as humans or horses, if infected birds are bitten by other kinds of mosquitoes that also feed on mammals. You can’t get EEE from an infected human, or from any other kind of infected mammal.

Because it’s spread by mosquitoes, the infection tends to be the biggest threat to warm, wet, mosquito-friendly climates, like those in the Northeast, Great Lakes and Gulf Coast regions.

Signs of ‘Triple E’

You can’t know if you have the virus just by looking at a mosquito bite. “Most people, if they have a reaction to a mosquito bite, that’s an allergic reaction,” Dr. Bhimraj says.

The majority of people who are infected with the EEE virus develop no symptoms or get a mild flu-like illness. The CDC reports that only about 4 to 5% of people who are infected develop dangerous brain swelling (encephalitis).

Advertising Policy

Those symptoms usually set in within 4 to 10 days after infection and may include:

  • Drowsiness.
  • Fever.
  • Headache.
  • Neck stiffness.
  • Chills.
  • Vomiting.
  • Seizures.

Although there is no specific treatment for this infection, anyone with these symptoms should seek immediate medical care. Healthcare professionals can provide supportive care in the form of IV fluids, breathing support and prevention of other infections.

The takeaway: Ward off mosquito bites

The best thing you can do to avoid EEE is straightforward — protect yourself from mosquitoes.

The CDC recommends you:

  • Use insect repellent that contains DEET, picaridin, IR3535 or oil of lemon eucaplyptus as directed.
  • Wear long sleeves and pants when going outside, especially if you’re in a wet or wooded area.
  • Make sure your window and door screens are intact and secure to keep mosquitoes out of your home.
  • Help reduce mosquito breeding by dumping out standing water in flower pots, buckets, barrels, bird baths, etc.

“These are universal precautions we should be taking anyway,” Dr. Bhimraj reiterates.

Advertising Policy
Advertising Policy