COLUMBUS -- Mosquitoes caught in a trap in suburban Cleveland tested positive for the potentially fatal West Nile virus, the Ohio Department of Health. Ohio is only the second state to have detected the virus in a mosquito trap this year.

The trap was set May 28 in Garfield Heights. The virus was detected in a pool of 50 mosquitoes, Dr. Richard Berry, chief of the department's

vector-borne disease program, said Wednesday.

New Jersey is the only other state to have found West Nile virus in a mosquito pool this year, Berry said. Ohio is working with local health departments to try and reduce the mosquito population.

Berry said fewer than 1 percent of mosquitoes carry West Nile virus, even in an affected area. About one in 150 people bitten by an infected mosquito will become severely ill.

The virus generally causes mild symptoms that mimic the flu in humans, state public health officials said. In some cases, people can develop deadly encephalitis -- swelling of the brain -- or meningitis -- inflammation of the covering of the brain and the spinal cord.

There is no known cure for the disease.

Mosquitoes spread the virus from infected birds to humans. Humans cannot pass the virus to one another.

In southwest Ohio's Warren County, a dead blue jay found in early June tested positive for the virus, said Larry Wiser, an administrator with the county health board.

''This just gives a little more emphasis that you need to protect yourself from the mosquitoes. It's just a warning sign that we have the virus in the area,'' Wiser said.

No human cases of the virus have been reported this year in the United States. But the federal Centers for Disease Control and Prevention recommends that people protect themselves against mosquito bites by getting rid of standing water, using insect repellent and wearing long sleeves.

West Nile was first detected in New York in 1999. Last

summer was the most severe so far, with 66 human infections and nine deaths reported.

Sporadic infections have been detected as far west as Illinois, Arkansas and Louisiana. Health officials have said that migratory birds will probably carry the virus farther west this season.

The virus also can kill horses, but there is a vaccine available to protect them from contracting the virus.

Mark Ulrich, a veterinarian in West Alexandria, said he has given hundreds of vaccinations to horses this year.

Horses need two vaccinations a year the first year they are vaccinated, and once a year after the initial dose, Ulrich said. Vaccinations cost about $25 each. The Associated Press