Eastern Equine Encephalitis (EEE), a potentially deadly viral illness spread by mosquitoes, has recently been in the news after a man died from the infection in New Hampshire. Several other people in Northeastern states have also been sickened, prompting some towns to take precautions like closing public parks at night. While EEE is rare, it’s important to understand what it is, how it spreads, and how to protect yourself.
EEE, also known as ‘triple E,’ is a virus that affects both humans and animals, particularly horses. It was first discovered in horses in Massachusetts in 1831, and human cases were documented about a century later. While sporadic cases and outbreaks have occurred throughout the years, primarily along the Atlantic and Gulf coasts, EEE is considered endemic to the United States.
In recent years, there have been between one and 15 EEE cases nationwide annually. However, 2019 saw an unusual spike with 38 cases, the reason for which is still unclear. This year, multiple states including New Hampshire, Vermont, Massachusetts, and New Jersey have each reported their first EEE case in several years. A person was also hospitalized in Wisconsin after contracting the virus in New England. So far in 2024, there have been six reported cases, with only four confirmed by the Centers for Disease Control and Prevention (CDC). One person has unfortunately died from the infection.
The virus is transmitted through mosquito bites. The mosquito species Culiseta melanura carries the virus and spreads it to birds, which serve as the primary reservoir for the virus. Other mosquito species then bite these birds and can subsequently pass the virus to mammals, including horses and humans. It’s important to remember that EEE can only be contracted through mosquito bites, not from infected people, horses, or birds.
While most people exposed to the virus through mosquito bites don’t experience any symptoms, some do develop a febrile form of the illness. This form is characterized by fever, chills, body aches, and joint pain. Most people recover from this form within one to two weeks. However, in a more serious scenario, the virus can invade the central nervous system, affecting the brain and spinal cord. This neuroinvasive form is deadly in about one-third of cases, and those who survive often experience long-term disabilities.
The neuroinvasive form typically manifests with fever, headache, vomiting, diarrhea, seizures, behavioral changes, drowsiness, and coma. Sadly, death often occurs within two to ten days of symptom onset. There are no vaccines or specific treatments for EEE, and those with the neuroinvasive form may require hospitalization for supportive care.
The best way to prevent EEE is to avoid mosquito bites. The CDC recommends using insect repellent, wearing long sleeves and pants when outdoors, and using air conditioning and screens on windows and doors to prevent mosquitoes from entering homes. Eliminating sources of standing water is also crucial. Some affected states, like Massachusetts, are spraying insecticides in areas where EEE has been detected in mosquitoes and horses.
While the number of EEE cases this year has not been out of the ordinary, it’s crucial to remain vigilant and practice mosquito-bite prevention measures. The potential for severe and even fatal complications underscores the importance of taking precautions and being aware of this potentially deadly disease.
