Mosquitoes in Portland tested positive for the West Nile Virus, the Maine Center for Disease Control (CDC) announced on Thursday, marking the first in the state to test positive for a mosquito-borne illness in the state this year.
The Maine CDC routinely tests mosquito pools—groups of 50 mosquitoes taken from targeted areas in the state—to determine whether they are carrying any diseases that could pose a risk to humans. Testing typically occurs during peak mosquito season in the summer and fall.
Though the Portland pool was the first this year to test positive for mosquito-borne illnesses, West Nile Virus was discovered earlier this year in birds in Kennebec, Sagadahoc, and York counties.
According to the U.S. CDC, West Nile Virus can cause symptoms within 2 to 14 days of infection; however, in 80 percent of cases, symptoms never manifest.
In nearly 20 percent of people, symptoms manifest as flu-like, and those infected typically recover completely but often suffer ongoing fatigue for weeks or even months after other symptoms end.
In under one percent of cases, the disease can be deadly and cause serious symptoms like encephalitis, swelling of the brain, or meningitis, as well as spinal cord inflammation.
The Maine CDC urged anyone experiencing severe symptoms to contact a doctor, “especially if a COVID-19 test is negative.”
They warned that Maine mosquitoes have also been known to carry Eastern Equine Encephalitis and Jamestown Canyon virus.
