For the first time in six years, a human case of Eastern equine encephalitis (EEE) was confirmed in Massachusetts earlier this month. The state Department of Public Health reports that the mosquito-borne illness recently was spread to a man in Plymouth County. Infectious disease experts from the MGH say while EEE is rarely transmitted to people, the risk for human infection usually peaks during the months of August and September.

“We’re really not in the clear until those first hard frosts settle in over New England,” says Edward Ryan, MD, director of MGH Global Infectious Diseases. “EEE is a virus that is usually transmitted among mosquitoes and non-human animals such as birds. But when a person is infected, it can be severe.”

Signs of EEE include flu-like symptoms, such as fever, muscle aches and headaches. The virus can cause inflammation of the brain and result in neurologic damage and, sometimes, death. Along with aerial spraying for mosquitoes, Ryan offers the following tips:

  • Avoid outdoor activity from dusk until dawn.
  • Cover exposed skin whenever possible.
  • Wear insect repellent approved by the Centers for Disease Control.
  • Remove standing water from yards where mosquitoes might thrive.

“There is no vaccine for EEE and no treatment,”says Ryan. “So it’s vital to minimize the likelihood of getting bitten by a mosquito.”