HEALTH UPDATE: Mosquito-Borne Illnesses and Schools

TO:        Superintendents, Heads of Private Schools, School Nurses, Principals, Athletic Directors and Coaches
FROM:  Maine Department of Education and Maine Center for Disease Control and Prevention
RE:        Mosquito-Borne Illnesses and Schools
DATE:   September 2019

Maine Department of Education (Maine DOE), in collaboration with Maine Center for Disease Control and Prevention (Maine CDC), is sharing this important guidance, developed by Maine CDC, with schools regarding mosquito-borne illnesses.

Three mosquito-borne illnesses are a local risk in Maine: Eastern Equine Encephalitis (EEE), Jamestown Canyon virus (JCV), and West Nile virus (WNV).  These are potentially serious viral infections, spread by the bite of an infected mosquito.  These diseases are especially severe in children (as well as adults over 50).  About one in every three people with EEE die, and many of those who recover have lasting health problems. It is important to practice prevention, since there is no vaccine or treatment for humans.

Maine saw the first human case of WNV in 2012, the first human case of EEE in 2014, and the first human case of JCV in 2017. Maine had two human cases of WNV and one human case of JCV in 2018. Maine also had one case of WNV in a horse and four WNV positive mosquito pools in 2018. Mosquito testing in Maine does not include JCV, and laboratory testing for JCV in humans is done out of state.

Maine identified an EEE positive horse in York County on August 30, 2019. To date in 2019, Maine has not identified any positive human or mosquito pools. Other northeastern states are reporting a very active season for EEE. Massachusetts is reporting one human death and four animal deaths from EEE. Hundreds of mosquito pools in Massachusetts have come back positive for EEE. New Hampshire also reports EEE positive mosquito pools and an EEE positive horse. Massachusetts also reports WNV positive mosquito pools.

The risk for getting a mosquito-borne disease 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 partners recommend:

  • Cover up outdoors. Children and others on outdoor field trips and participating in outdoor activities for a significant amount of time, when the temperature is above 50 degrees, should cover up with long sleeve shirts, long pants, and long socks.
  • Use repellent.   Use an EPA approved repellent containing DEET, picaridin, IR3535, or oil of lemon eucalyptus on skin. The repellent permethrin can be used on clothing and can be remain effective through several washes. Always follow the package directions.  See here for details on recommended repellents.  Schools that schedule practices or games at dusk or evening with temperatures above 50 degrees should encourage the use of repellent for all participants, including coaches and observers.  Please note:  School employees and volunteers must have authorization from parents/guardians before applying repellents to minor children (CMR 01-026, Chapter 10, Section 2.I.4.iii).
  • 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.  Review information on Maine’s School IPM Program. 
  • Monitor Maine CDC’s arboviral website for the most up to date information on confirmed detection in the state. If mosquito-borne disease activity increases in your area, the following strategies should be implemented:
    1. Strongly encourage the use of EPA approved repellents.
    2. Talk with your school IPM coordinator and implement a plan to reduce the number of mosquitoes and mosquito breeding sites on school grounds.
    3. Limit and/or reschedule evening outdoor activities. Unless the dusk temperature is forecast to be less than 50 degrees, limit or reschedule outdoor evening activities such as school athletic events so people are able to go indoors by one hour before sunset.

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.

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

Maine DOE 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.