Maine CDC Press Release

August 23, 2012

Second Mosquito Pool Tests Positive for West Nile Virus

Additional Increase in Positive Tests in Mosquitoes Expected; Maine CDC Offers Prevention Tips

AUGUSTA – The Maine Center for Disease Control and Prevention has confirmed the presence of West Nile Virus (WNV) in a mosquito pool from the town of Gorham in Cumberland County. This is the second mosquito pool from Maine to test positive for WNV in 2012.

WNV is a virus that is transmitted through the bite of an infected mosquito. It can cause serious illness in humans, large animals like horses and some species of birds. Prior to 2012, the last time WNV was identified in Maine was in 2010.

There has been a recent increase in regional WNV activity over the last month, including multiple positive mosquito collections in New Hampshire, as well as human and equine cases in Massachusetts and just recently, a human case in New Hampshire. Dr. Stephen Sears, State Epidemiologist, said that an increase in activity is expected to continue in Maine and that more positive tests in mosquito pools is likely.

Maine CDC recommends the following preventative measures to protect against WNV and other mosquito-borne illnesses:

  • Use an Environmental Protection Agency-approved repellent when outdoors, especially around dawn and dusk. Always follow the instructions on the product’s label;
  • Wear protective clothing when outdoors, including long-sleeved shirts, pants and socks;
  • Keep window and door screens down to keep mosquitoes out of the home;
  • Limit time outdoors at dawn and dusk when many species of mosquitoes are most active;
  • Remove containers holding water in and around the home, as water can attract mosquitoes.

Maine's Health and Environmental Laboratory (HETL) routinely performs testing for WNV and Eastern equine encephalitis (EEE) in mosquitoes, large animals and humans. Maine stopped testing individual dead birds for mosquito-borne illnesses in 2006 and no longer uses them as an indicator for disease.

The Maine CDC will continue to update information on mosquito-borne disease surveillance in Maine on a weekly basis. These reports are posted every Monday from May through September at

Future positive tests will be announced through this report.

Information on pesticides and repellents is available at the Maine Board of Pesticides Control website at: