Severe cases of the Jamestown Canyon virus can cause encephalitis, meningitis and even death, according to the Maine CDC.
This 2014 photo shows a feeding female Anopheles gambiae mosquito. Credit: James Gathany / U.S. Centers for Disease Control and Prevention via AP

A mosquito-borne disease that can cause brain swelling has been detected in York County.

The Jamestown Canyon virus was found in a group of mosquitoes in Wells, the first time the virus has been detected in Maine since 2019, according to Lindsay Hammes, a spokesperson for the Maine Center for Disease Control and Prevention.

Hammes noted there have been no confirmed cases of Jamestown Canyon virus or any other mosquito-borne disease in a Mainer so far this year.

Jamestown Canyon virus is spread through the bite of an infected mosquito. It cannot be spread to humans from other animals or from person to person.

Its symptoms include fever and flu-like illness, but more severe symptoms include encephalitis, meningitis and even death, according to the Maine CDC. Anyone experiencing these symptoms should contact their doctor.

About half of people who contract the virus are hospitalized, and death remains rare, according to the U.S. Centers for Disease Control and Prevention.

Only 17 cases of Jamestown Canyon virus are reported on average every year, according to the CDC, which considers the virus significantly underreported. While the virus is found throughout the United States, most cases are reported in Minnesota and Wisconsin.

So far this year, there have been just three confirmed cases, one in New York and two in Michigan, according to the CDC.

The Maine CDC tests for mosquito-borne viruses like eastern equine encephalitis and West Nile virus throughout the summer, starting in July.

Mainers can protect themselves from those and other mosquito-borne diseases by wearing loose-fitting long-sleeve shirts and long pants, using bug repellant, draining any standing water on their property, and putting screens in doors and windows.