Eastern Equine Encephalitis

Eastern Equine Encephalitis

Public Health Fact Sheet

What is Eastern Equine Encephalitis?
Eastern Equine Encephalitis, or EEE, is a very rare but serious disease caused by a virus that is transmitted to humans and horses through mosquito bites. This form of encephalitis occurs mainly along the Eastern seaboard of the United States, on the eastern Gulf coast, and in some inland Midwestern states.

What is the EEE virus?
The EEE virus is one of many viruses in the arbovirus family, which is shorthand for arthropod-borne virus.

How is Eastern Equine Encephalitis spread?
The virus that causes EEE lives almost exclusively in the bloodstream of infected birds, and in the mosquitoes that bite those birds.

What can we do to prevent EEE?
There is no vaccine for people, but there is a vaccine for horses, which should be updated every spring. The best way to protect yourself is to avoid mosquito bites as much as possible, by: 

  • Using repellents. Insect repellents containing 20-30% DEET work best. Follow the label instructions carefully.
  • Limiting outdoor activity in the evening, when mosquitoes are most active.
  • Maintaining window and door screens to keep mosquitoes out.
  • Reducing mosquito populations; eliminate all standing water that collects in birdbaths, boats, buckets, tires, unused pools, roof gutters, and other containers.
  • Avoiding shaded areas where mosquitoes may be resting.
  • Wearing protective clothing such as long-sleeved shirts and pants.
Symptoms of Eastern Equine Encephalitis
  • Abrupt onset of fever
  • Headache
  • Body aching
  • Disorientation
  • Change in level of consciousness
  • Varying paralysis
  • Coma