In Washington County, three dead crows tested positive for West Nile virus in August. One of those crows was found at the Roxbury Correctional Institution, one of three medium-security prisons south of Hagerstown. The others were found at the intersection of Mount Aetna Road and Md. 66, and at Greenbrier State Park.
In Pennsylvania, a dead crow found in Greencastle, tested positive for the virus earlier this month, and last week, a blue jay found in Chambersburg, Pa., tested positive for the virus.
Infected mosquitoes carry the West Nile virus and can spread it by biting a human, animal or bird.
In humans, symptoms of the virus are usually mild, but the most severe cases can be fatal, health officials say.
Elderly persons or those with weakened immune systems are at most risk of suffering severe complications, Cannarella.
"This shouldn't cause panic but it should cause people to become more aware," Cannarella said Monday.
Cannarella called the public's attention to steps they can take to avoid the disease.
Those steps include eliminating pools of stagnant water where mosquitoes can breed, wearing long-sleeved shirts and long pants when outdoors and applying insect repellent containing DEET.
High concentrations of DEET can cause harmful side-effects, so health officials recommend that adults not use a repellent that contains more than 23.8 percent DEET, said Cannarella.
Children under 2 years of age should only use a repellent containing no more than 4 percent DEET, said Cannarella.
Children using repellent with the lower concentration of DEET need to have the repellent re-applied more often - about every half hour - because of the lower concentration, Cannarella said.