HEALTH ALERT: Mosquito-borne illnesses and schools

We are sharing the following letter from Stephen Sears, MD MPH, State Epidemiologist, with the Maine Center for Disease Control, to whom we defer on all public health issues. Please share this letter with school principals and school nurses.

The Maine Department of Education, in collaboration with the Maine Center for Disease Control and Prevention, is sharing this important guidance to schools regarding mosquito-borne illnesses. The information and guidance in this letter was developed by Maine CDC.

Two mosquito-borne illnesses are considered endemic in Maine: Eastern Equine Encephalitis (EEE) and West Nile virus (WNV). Both are potentially serious viral infections transmitted to people from the bite of an infected mosquito. The disease is especially severe in children (as well as adults over 50). There is no vaccine or effective treatment for humans. Therefore, prevention strategies are critical.

Both EEE and WNV have previously been identified in Maine. EEE was last identified in 2009 when a large animal outbreak killed multiple horses, a llama and some pheasants. WNV was identified in a pool of mosquitoes in August 2012. Both viruses have been detected during 2012 in New England (WNV in New Hampshire, and both EEE and WNV in Massachusetts).

The risk for contracting mosquito-borne diseases is highest from dusk to dawn and when temperatures are above 50 degrees (and especially above 60 degrees), since these are the conditions when mosquitoes are most actively biting.

Schools play an important role in preventing mosquito-borne illnesses. Maine CDC and its consulting experts recommend you:

  • Cover up outdoors. Children and others on outdoor field trips and participating in other outdoor activities for a significant amount of time when the temperature is above 50 degrees should be encouraged to:
  • Implement Integrated Pest Management strategies. Since we anticipate the risk from mosquito-borne illnesses to continue, schools should consult with their IPM coordinator to review their IPM policy. Information on Maine’s School IPM Program can be found at

If mosquito-borne disease activity increases, other strategies to minimize exposures to the mosquitoes that can transmit EEE and WNV may include:

  • Consider limiting/rescheduling evening outdoor activities. Unless the dusk temperature is forecast to be less than 50 degrees, consider limiting or rescheduling outdoor group evening activities, such as school athletic events, so people are able to go indoors by one hour before sunset, or make sure participants and spectators know to use repellent.

All these recommendations are especially true in those areas with previously identified mosquito-borne illnesses. However, the lack of identified virus in an area of the state does not mean there is no risk.

Maine CDC has one-page fact sheets for EEE, WNV and repellents, which we encourage you to send home with students, share by email and/or post on your school website(s), as you deem appropriate. You can access the facts sheet here:

Resources to learn more about mosquito-borne illness and mosquito control:

Maine Department of Education and Maine CDC continue to work very closely together and are greatly appreciative of your assistance in keeping Maine’s children and school communities healthy.

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