Deadly mosquito virus discovered in Massachusetts: These are the symptoms you should know

Massachusetts is on high alert for Eastern equine encephalomyelitis, a rare but potentially life-threatening viral disease transmitted by mosquitoes, after health officials confirmed the first human case in the state in four years.

Ten communities in Massachusetts are currently considered critical or high-risk communities for the virus, also known as Triple E or EEE, the Massachusetts Department of Public Health said.

In these areas, officials are spraying mosquito repellent from planes and trucks to control Eastern equine encephalomyelitis. Several cities have announced plans to close parks at night and impose voluntary curfews to limit mosquito exposure during the dusk-to-dawn period when mosquitoes are most active.

The patient, a man in his 80s, was exposed to the virus in the city of Worcester, the Massachusetts Department of Health said in an August 16 press release.

According to the U.S. Centers for Disease Control and Prevention, Eastern equine encephalomyelitis is transmitted to humans through the bite of an infected mosquito.

Infection can cause inflammation and swelling of the brain. About 30% of those infected die, and survivors often suffer from persistent neurological problems, according to the CDC.

News of the Massachusetts case comes as another virus spread by blood-sucking insects, West Nile virus, is circulating in the United States. In early August, a woman in Dallas, Texas, died from contracting West Nile virus. Just this week, it was revealed that Dr. Anthony Fauci, Joe Biden's former chief medical adviser, was hospitalized with West Nile virus.

“We are in a critical season for mosquito-borne diseases of all kinds, including epidemic influenza E, which carries a higher risk of hospitalization and potentially fatal outcomes,” said Dr. Kavita Patel, a family medicine physician and medical contributor to NBC News, in a TODAY segment that aired Aug. 26.

What is the disease EEE?

EEE stands for Eastern Equine Encephalitis, a rare but serious disease caused by the Eastern Equine Encephalitis virus that can infect mosquitoes, humans, and a range of animals. According to the CDC, the virus is found in North America and the Caribbean.

In humans, the virus can attack the central nervous system, including the brain and spinal cord, causing severe illness or death.

According to the CDC, there are only a handful of human cases of Eastern equine encephalomyelitis in the United States each year. There were seven cases in 2023, one in 2021, and 13 cases in 2020. In 2019, there were 38 cases in the United States, the highest annual number in over a decade.

Infections peak in the summer months, but according to the Cleveland Clinic, cases can last into early fall.

What is the mortality rate from electrical and electronic devices?

About 30% of people infected with EEE die because the infection can cause inflammation and swelling of the brain. Survivors often suffer permanent neurological problems, according to the CDC.

How is Eastern equine encephalomyelitis transmitted to humans?

In nature, the Eastern equine encephalomyelitis virus is maintained by a cycle between mosquitoes (particularly the species Culiseta melanura).) in freshwater marshes and wild birds, which the CDC says are reservoirs for the virus.

Since this species of mosquito feeds mainly on birds, they are not a major transmitter of the virus to humans.

According to the CDC, the Eastern equine encephalomyelitis virus is transmitted to humans when another species of mosquito that bites humans and birds (such as the Culex mosquito, which also spreads West Nile virus) becomes infected and forms a “bridge” between the infected birds and uninfected humans.

Humans are considered a “dead-end host.” Eastern equine encephalomyelitis cannot be transmitted from person to person or from horse to person.

There have been rare cases of Eastern equine encephalomyelitis in humans transmitted through organ transplants.

What are the symptoms of Eastern equine encephalomyelitis?

Most people who become infected with Eastern equine encephalomyelitis do not experience any symptoms. If symptoms do occur, they usually begin within four to 10 days of being bitten by an infected mosquito, according to the CDC.

Symptoms of Triple E include:

• Fever
• chills
• Muscle pain
• Joint pain

These typically last one to two weeks, and most people recover completely if the central nervous system is not affected by the virus, according to the CDC.

Severe infection with Eastern equine encephalomyelitis can cause a neurological disease that can result in inflammation of the brain (encephalitis) or the tissue surrounding the brain and spinal cord (meningitis).

According to the CDC, symptoms of severe Eastern Equine Encephalomyelitis include:

• High fever
• Behavioral changes
• Seizures
• Vomit
• Diarrhea
• coma

These complications can become life-threatening, and about one in three people with Eastern equine encephalomyelitis die from it. Many people who recover have long-term mental and physical problems, including intellectual disabilities, seizures or personality disorders, according to the CDC.

Where in the United States is Eastern equine encephalomyelitis spreading?

In the United States, cases of Eastern equine encephalomyelitis occur most frequently in the Eastern and Gulf Coast states.

According to CDC data as of August 20, three human cases of Eastern equine encephalomyelitis have been reported in the United States, all of which were severe (neuroinvasive). These cases were reported in three states:

• Massachusetts
• New Jersey
• Vermont

According to the Cleveland Clinic, cases most commonly occur near freshwater bodies, including swamps and coastal areas.

In Massachusetts, the communities of Worcester County and Plymouth County are considered particularly at risk according to health authorities. To reduce the risk of electrical and electronic equipment, the following communities are being sprayed:

• Carver
• Halifax
• Kingston
• Middleborough
• Plymouth
• Plympton
• Rochester
• Wareham
• Douglas
• Dudley
• Oxford
• Sutton
• Uxbridge

Treatment of Eastern Equine Encephalomyelitis

There is no cure or specific treatment for Eastern equine encephalomyelitis. Antibiotics are not effective because the infection is caused by a virus.

Treatment often focuses on relieving symptoms, such as rest, fluid intake to avoid dehydration, and over-the-counter pain relievers, according to the Cleveland Clinic.

Severe cases of Eastern equine encephalomyelitis may be treated in hospital and require additional monitoring and supportive care.

How to prevent Eastern equine encephalomyelitis

There is no vaccine to protect against Eastern equine encephalomyelitis. The best way to reduce your risk of Eastern equine encephalomyelitis and other mosquito-borne diseases is to protect yourself from mosquito bites.

According to the CDC, you can take the following steps to prevent mosquito bites:

• Apply an EPA-approved insect repellent
• Wear long-sleeved shirts and pants outside
• Limit your outdoor activities to the hours between dusk and dawn, when mosquitoes are most active.
• Drain or empty standing water around the house where mosquitoes can breed