EEE: What You Should Know

The number of mosquitoes infested with Eastern equine encephalitis (EEE) in Massachusetts is the highest it has been in three decades, a "top health official" told The Boston Globe.

The summer's second round of aerial spraying is scheduled to take place in the coming days.

What is EEE?

EEE is a disease caused by a virus.

According to the Massachusetts Department of Public Health (MDPH), EEE is very rare:

Since the virus was first identified in Massachusetts in 1938, fewer than 100 cases have occurred. Over 60 percent of those cases have been from Plymouth and Norfolk counties.

Public health officials are responsible for collecting and testing mosquitoes for disease, including EEE, throughout the summer season. When the disease is found, "public health officials issue warnings to the public."

Most of the time, regional mosquito control workers will drain standing water or kill larvae developing in mosquito habitats to help combat the spread.

If the risk becomes "too great," state agencies consider whether or not to spray towns with insecticides by airplane.

How does it spread?

The virus infects birds that live in freshwater swamps and is spread from bird to bird by infected mosquitoes. If a mosquito infected with the virus bites a horse or human, the animal or person can become sick.

Although humans and several other types of mammals, particularly horses and llamas, can become infected, they do not spread disease.

A list of common disease-carrying mosquitoes in Massachusetts can be found here.

How serious is EEE?

Mass DPH:

EEE can cause severe illness in any age group; however people under the age of 15 are at particular risk. The death rate for humans who get EEE is high, and survivors often suffer severe neurological damage.

Why is it such a risk now?

The risk of getting EEE is typically highest annually from late July through early September.

However, more mosquitoes survived this past winter due to the unseasonably warm temperatures in New England. More mosquitoes around during the summer means more potential carriers of EEE.

What symptoms should you look out for?

The first symptoms of EEE that occur are flu-like: they include a fever (often 103 degrees to 106 degrees Fahrenheit), stiff neck, headache and a lack of energy — all of which occur three to 10 days after a bite from an infected mosquito.

Inflammation and swelling of the brain, called encephalitis, is the most dangerous complication. Some patients who have contracted EEE fell into a coma within a week.

What should you do to prevent it?

MDPH and the Massachusetts Department of Health and Human Services have listed a handful of suggestions to prevent yourself from contracting EEE: