Eastern Equine Encephalitis: A Rare but Deadly Mosquito-Borne Virus

A Culiseta melanura mosquito. Image from CDC's page.

The main points

• Eastern equine encephalitis is caused by a virus spread to people by the bite of an infected mosquito.
• It is rare but serious.
• People who live where the virus circulates should prevent mosquito bites.

How common, how serious

Only a few cases are reported in the United States each year, mostly in eastern or Gulf Coast states. But about 30% of people who develop severe illness die, and many survivors have lasting neurologic problems.

Symptoms

Fever, headache, vomiting, diarrhea, seizures, behavior changes and drowsiness. More on symptoms.

How it spreads

Through the bites of infected mosquitoes — and, rarely, through solid organ transplants. More on causes and spread.

Prevention

There are no vaccines or medicines to prevent it in people. The way to lower your risk is to prevent mosquito bites — see CDC's prevention advice.

Diagnosis and treatment

• See a health care provider if you have symptoms after mosquito exposure where the virus spreads.
• No medicines treat it, and antibiotics don't work against viruses.
• Rest, fluids and over-the-counter pain relievers may ease some symptoms.
• People with severe disease often need hospital care — IV fluids, pain medicine and nursing care.

For health care providers: treatment and prevention guidance.

Sources

Based on "Eastern Equine Encephalitis," Centers for Disease Control and Prevention; a work of the United States government in the public domain.