By JOHN SEEWER, Associated Press Writer
TOLEDO, Ohio (AP) - Dozens of birds of prey -- among hundreds that have died in recent weeks in the Midwest -- are being tested for the West Nile virus.
Some wildlife watchers worry an unstoppable disease is spreading and could infect threatened and endangered species.
About 400 owls and hawks have died recently in Ohio, state and federal wildlife officials estimate. Dead raptors also have been found in Michigan, Kentucky, Indiana and Iowa.
"This is a major die-off," said Mark Shieldcastle, a wildlife biologist in Ohio. "These birds are being found in lawns, on golf courses."
Wildlife officials are careful, though, to say they are not certain the mosquito-borne virus is responsible. West Nile has killed at least 21 people nationwide this year, and is fatal to birds and horses.
"It's either West Nile or something else we don't know about," Shieldcastle said. "It could go in a lot of different directions."
Infected birds and mosquitoes can serve as an early warning system for the presence of the West Nile virus. The virus most commonly has been found in blue jays and crows but has been confirmed in 111 bird species nationwide.
In Ohio, dozens of great horned owls and red-tailed hawks have been found either dead or near in the last two weeks. Some were shaking and suffering from a lack of coordination.
Seven of eight birds tested last week had the virus. More samples are being tested at state labs and at the National Wildlife Health Center in Madison, Wis.
"A bird came in looking healthy and it was tremoring all over," said Kathryn Converse, wildlife disease specialist with the center. "Some die rapidly and some linger over days despite treatments."
Researchers at Michigan State university are testing a handful of raptors found dead in the southern part of the state. Initial tests showed suspicious signs of the virus, said Jon Patterson, a veterinary pathologist.
Wildlife researchers are puzzled why so many raptors have died in Ohio in recent weeks but not in states where the virus is more established.
"I have no idea why," Converse said.
Some bird rehabilitation centers have reported finding more dead birds of prey in the last weeks than they normally would see in a year.
So far, Ohio has no reports of dead bald eagles, ospreys or peregrine falcons, all endangered species in the state.
"We're very concerned, especially about the eagle population," Shieldcastle said. "It could have a devastating effect on their recovery.
"Most likely there's not a thing we can do about it if this is a viral thing."
People have been diagnosed with West Nile in 20 states and the District of Columbia.
The virus has been reported from the Gulf of Mexico to the Great Lakes, but it has done most of its damage this year in the South. In Louisiana, there have been 171 human cases and eight deaths.