EEE Virus: Mosquito-Borne
Eastern Equine Encephalitis (EEE) is a rare cause of brain infections (encephalitis). Only a few cases are reported in the U.S. each year. Most occur in eastern or Gulf Coast states. Approximately 30% of people with EEE die, and many survivors have ongoing neurologic problems.
EEE was first recognized in horses in 1831 in Massachusetts. The first confirmed human cases were identified in New England in 1938.
According to CNN (9-25-19), 10 people have died from this mosquito-borne illness in 2019. EEE virus has caused 27 human cases in 6 states since August 2019. In 2018 there were 6 reported cases.
EEE is transmitted to humans (and horses) through the bite of an infected mosquito
The primary transmission cycle takes place in and around swampy areas
About 4-5% of human EEE virus infections result in EEE
Infection is thought to confer life-long immunity against re-infection
In the U.S., an average of 7 human cases of EEE are reported annually
The incubation period of EEE (the time from infected mosquito bite to onset of illness) ranges from 4 to 10 days. It can result in one of two types of illness:
Systemic (affecting the entire body)
Muscle and joint pain
The illness lasts 1 to 2 weeks, and recovery is complete when there is no nervous system involvement.
Encephalitis: (affecting the brain)
Loss of appetite
Vomiting and diarrhea
Cyanosis (bluish coloring)
About 1/3 will die from EEE. Many are left with disabling and progressive mental and physical complications, which can range from minimal brain dysfunction to severe intellectual impairment, personality disorders, seizures, paralysis, and cranial nerve dysfunction. Many patients with severe complications die within a few years.
Preliminary diagnosis is often based on the patient’s symptoms, places and dates of travel, activities, and epidemiologic history of the location where the infection occurred
Laboratory test of blood and spinal cord fluid
Treatment: There is no vaccine or anti-viral treatment available
Prevention: Prevent mosquito bites
Insect Repellent: Use Environmental Protection Agency (EPA)-registered insect repellents with one of the active ingredients below:
Oil of lemon eucalyptus
Always follow the product label instructions.
Reapply insect repellent as directed.
If you are also using sunscreen, apply sunscreen first and insect repellent second.
Wear long-sleeved shirts and long pants
Apply insect repellent to clothing and gear. Don’t apply directly to the skin
Use screens on windows and doors. Repair holes in screens to keep mosquitoes outdoors
Use air conditioning, if available
Stop mosquitoes from laying eggs in or near water: Once a week, empty and scrub, turn over, cover, or throw out items that hold water, such as tires, buckets, planters, toys, pools, birdbaths, flowerpots, or trash containers