Maine CDC Press Release

October 31, 2012

Maine Identifies First Case of West Nile Virus In Human

AUGUSTA – The Maine Center for Disease Control and Prevention announced today that it has identified the state’s first-ever case of West Nile virus (WNV) in a Maine resident from Cumberland County. The patient, who has now recovered, presented with symptoms including fever, encephalitis, meningitis, weakness and double vision. The symptoms began on October 1. Since the patient had not traveled during the exposure period, this is considered a locally acquired case. WNV is a virus that is transmitted through the bite of an infected mosquito. It can cause serious illness in humans, large animals and some species of birds. Nationally and regionally, 2012 has been an extremely active year for WNV. Prior to this human case, seven mosquito pools in Maine tested positive for WNV in August and September. Five of the positive mosquito pools came from Cumberland County and the other two were in York County. A Pennsylvania resident vacationing in Maine in August also tested positive for WNV earlier this year; however the infection was likely contracted out of state. While winter is approaching in Maine, the temperatures are still high enough to support mosquito activity. "As long as the temperatures remain above freezing there is potential for West Nile virus transmission," said Dr. Stephen Sears, State Epidemiologist. Mosquitoes will remain active until the first hard frost of the season. While some parts of Maine have already experienced their first hard frost, others have yet to reach freezing temperatures, making it important to remember to protect against mosquito exposures.

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

  • Use an EPA 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
  • Use screens on windows and doors to keep mosquitoes out of the home
  • Avoid or limit time outdoors at dawn and dusk when many species of mosquitoes are most active
  • Practice household mosquito-source reduction: standing water should be removed from artificial water-holding containers in and around the house

The MeCDC will continue to monitor mosquitoes and expects to see the virus again in the spring when it will be brought by migrating birds. The Department of Agriculture, Conservation and Forestry notes that both WNV and Eastern Equine Encephalitis are reportable diseases in animals as well. Dr. Beth McEvoy, Acting State Veterinarian, reminds horse owners that both viral diseases are preventable with vaccines.