It’s the peak time of year for mosquitoes, including mosquitoes that can spread diseases like West Nile virus and eastern equine encephalitis (commonly known as EEE or triple E).

The Massachusetts Department of Public Health announced on July 1 that West Nile virus has been detected this season in mosquitoes in Massachusetts. There were eight human cases of West Nile in 2020, but a record 49 human cases in 2018.

All West Nile- and EEE-positive results are posted on the DPH’s Arbovirus Surveillance Information web page, which is updated daily. The DPH also produces West Nile and EEE risk maps for every community in the state and has published a range of arbovirus information to assist local boards of health.

West Nile Virus and EEE can cause illness ranging from a mild fever to more serious disease like encephalitis or meningitis. Only a small number of mosquitoes are infected at any given time, so being bitten by a mosquito does not mean you will get sick. The best way to avoid these illnesses, however, is to prevent mosquito bites.

Public health officials recommend that residents do the following to protect against illness:
• Use insect repellents whenever outdoors
• Wear long-sleeved clothing
• During peak mosquito season, schedule outdoor activities to avoid the hours from dusk to dawn
• Repair damaged window and door screens
• Remove standing water from the areas around homes

For more information, see the DPH’s frequently asked questions about mosquitoes in Massachusetts, or call the Division of Epidemiology at 617-983-6800.