EEE Information, Management and Updates

Published July 2, 2021 | Health Department | Automatically Archived on 10/17/2021

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What is EEE and how, where and when does EEE spread?

Eastern Equine Encephalitis (EEE) is a rare but serious disease caused by a virus.  The first symptoms of EEE are fever (often 103º to 106ºF), stiff neck, headache, and lack of energy. These symptoms show up three to ten days after a bite from an infected mosquito.  Inflammation and swelling of the brain, called encephalitis, is the most dangerous and frequent serious complication. [1] Approximately one third of people who contract EEE die, and survivors often experience mild to severe disability from brain damage.

The virus that causes EEE is spread through the bite of an infected mosquito. In Massachusetts, the virus is most often identified in mosquitoes found in and around freshwater, hardwood swamps.

Outbreaks of EEE usually occur in Massachusetts every 10-20 years. These outbreaks will typically last two to three years[2].


What is being done in Sudbury to minimize risk of exposure to EEE?

The Sudbury BOH has implemented the following in response to EEE being identified in the community in 2019:

  1. Increased surveillance and trapping locations, testing for mosquito type and quantity in cedar swamps where there is highest opportunity for breeding.
  2. Increased mosquito testing, which includes testing higher quantity of mosquitos more frequently.
  3. Decreased turn-around time for results of mosquito testing, from about a week to 1-2 days.


Mosquito Spraying:

East Middlesex Mosquito Control and Suffolk County Mosquito Control began aerial larvicide spraying in the spring.  Response plans are formulated using a science-driven process based on surveillance and specifies precise locations and times for spraying. If and when there is a need for adulticide spraying, there will be a public notice and info on precautions.  



What precautions can residents take to minimize risk of exposure to EEE?

Being outdoors benefits health and wellbeing. Especially during COVID, it is important to spend time outside. Use of repellants and protective clothing limits risk of being outdoors.

  • Minimize time outdoors at dawn and dusk when mosquitoes are most active. 
  • Wear light-colored socks, long pants, and a long-sleeved shirt to cover up your skin. 
  • When outdoors, use an Environmental Protection Agency (EPA)-registered insect repellent with one of the following active ingredients:

                   – DEET 

                   – Picaridin

                   – IR3535

                   – Oil of lemon eucalyptus (OLE)

                   – Para-menthane-diol (PMD)

                   – 2-undecanone 

  • Remove any sources of standing water near your home. 
  • Make sure window screens are tight-fitting. 
  • Cover cribs, strollers, and baby carriers with mosquito netting.[3]



For more information, please refer to the following websites:


Massachusetts Department of Public Health


Centers for Disease Control and Prevention


An informative video produced by the Town of Ipswich can be found here: