By Glynn Cosker
Managing Editor, EDM Digest

Eastern Equine Encephalitis (EEE) virus has caused several deaths in numerous states in one of the worst seasons for the mosquito-borne virus in recent memory.

EEE Virus Cases in 2019 Alarmingly Higher Than Normal

EEE virus affects mostly birds and mammals – particularly horses. It is also a rare cause of brain infections in humans with most cases occurring in the Eastern and Gulf states of the U.S. In humans, it is fatal around 33 percent of the time. The disease spreads to humans via bites from mosquitoes that have fed on infected birds.

According to the Centers for Disease Control and Prevention (CDC), 72 human EEE virus cases resulted in 30 fatalities from 2009 to 2018. However, there are 27 confirmed cases this year alone and nine deaths – representing a major uptick in infections that is baffling scientists and medical officials. There is no human vaccine against EEE virus infection and no treatment regimen is available.

EEE Virus Prevalence in Humans

(Data source: CDC)

Six States Affected by EEE Virus

Massachusetts has seen 10 human cases of EEE so far this year – three of which were fatal. According to CNN, there has also been eight cases in Michigan, including three deaths; two cases in Connecticut, both of them fatal; three cases in Rhode Island, including one death; three cases in New Jersey; and one case in North Carolina.

“We haven’t seen anything like this since 1996,” said Connecticut’s state epidemiologist, Dr. Matthew Carter. “In 1996, there were a number of infections that led the state to do more ground and aerial spraying for mosquitoes, but those events occurred earlier in time than where we are right now in September 24.”

EEE Virus Prevention

Avoiding the mosquito bites that cause the disease is the first line of defense. Here is a list of tactics to avoid the infection from the Boston Public Health Commission:

• Use a mosquito repellent. Repellents approved by the EPA include those containing DEET, oil of lemon eucalyptus, Picaridin or IR3535.

• Wear protective clothing such as long-sleeved shirts, long pants and socks whenever possible. Tuck your shirt into your pants to keep mosquitoes from going under your clothes.

• Although mosquitoes can bite at any time of day, try to limit your time outdoors between dusk to dawn when mosquitoes are most active.

• Make sure window and door screens don’t have holes in them.

EEE Virus Symptoms in Humans

Sometimes, no symptoms occur in a person infected with EEE virus. However, some people have mild, flu-like symptoms that disappear in time.

Unfortunately, about 20 percent of people infected with EEE virus subsequently develop a serious illness. Additionally, about 50 percent of those infected develop neuroinvasive disease, which triggers encephalitis – the nearly always fatal brain-swelling condition. This serious phase of the infection usually involves a sudden onset of a headache, chills, high fever, and vomiting before progressing further to disorientation, seizures, and death.

EEE Virus Outlook

The good news is that EEE virus cases will dramatically decline once the affected states’ mosquito population dies off – usually after the first sub-zero frost of the fall. In the meantime, vigilance against mosquito bites is the best approach to avoiding the infection if you live in one of the affected areas of the United States.