Mosquitoes in Massachusetts

The Latest Response to Mosquitoes in Sherborn

Last Updated October 16th, 2025 - For more recent information, please call 508-651-7852 or email health@sherbornma.org

There are 51 different kinds of mosquitoes that have been found in Massachusetts and mosquitoes are usually found in damp, shady areas. Some mosquitoes carry germs that can make people and animals sick when they bite. In Massachusetts, the diseases linked to mosquitoes are West Nile Virus (WNV) and eastern equine encephalitis (EEE) virus.  

Eastern Equine Encephalitis (EEE)

Quick facts about EEE

  • EEE is spread through the bite of infected mosquitoes.
  • EEE symptoms begin 3 to 10 days after a bite from an infected mosquito.
  • EEE is very rare, in 88 years, there have been just 115 cases.

West Nile Virus (WNV)

Quick facts about WNV

  • WNV is spread through the bite of an infected mosquito, but can also be spread through blood transfusion or organ transplant.
  • Majority of people with WNV will have no symptoms. 
  • Approximately 20% of people infected with WNV will develop mild symptoms.
  • Less than 1% of people infected with WNV will develop severe symptoms. Persons older than 50 years of age have a higher risk of developing severe illness.



Mosquito Prevention use EPA bug spray with DEET, wear long sleeves, know active mosquito times

Local Risk Levels for Mosquito-Borne Diseases in Massachusetts

The Massachusetts Arbovirus Dashboard is updated based on seasonal testing from June to October.