A 46-year-old Mercer County man was diagnosed Monday with the West Nile virus, according to the Pennsylvania Department of Health. Laboratory results confirmed it as the first human case in Mercer County.

"It's the first case but not terribly unexpected," said Richard McGarvey, of the department of health. "We know we can find the virus anywhere in the state."

He said the infected man is alive and was hospitalized, but further information regarding his condition is unavailable.

So far this year in Mercer County, West Nile has been found in 14 dead birds, one mosquito sample and no cases of sentinel and vet samples. Sentinels are watched chicken flocks and horses near high concentrations of mosquitoes that are tested weekly for the virus, McGarvey said.

In Pennsylvania there have been 18 human cases reported, with three deceased, 648 dead birds, 286 mosquito samples and 93 sentinel and vet samples.

The first human case in Pennsylvania was reported on Aug. 31 from a 66-year-old Lancaster County man who eventually recovered. The second case was an 87-year-old Allegheny County man who died earlier this month.

The tests are performed by the Department of Health State Public Health Laboratory in Lionville, Chester County, and results are 95 percent accurate. Samples are sent to the Centers for Disease Control and Prevention in Atlanta for final tests.

Anyone can get the virus but the elderly are more at risk because of a weaker immune system. Most people infected with West Nile virus have no symptoms of illness, but some may become sick three to 15 days after the bite of an infected mosquito. Health authorities believe about one in five infected people will have mild illness with fever, headache and body aches, sometimes with skin rash and swollen lymph glands. Only about one in 150 people infected with West Nile virus will have the more serious illnesses of encephalitis or meningitis and will need medical followup, McGarvey said.

Symptoms of encephalitis (inflammation of the brain) and meningitis (inflammation of the spinal cord and brain linings) include severe headache, stiff neck, stupor, disorientation, coma, tremors, muscle weakness, convulsions and paralysis.

McGarvey suggests people can protect themselves outdoors by covering up or using insect repellent with DEET.