Trumbull County health officials have sent dead blue jays to Columbus for tests.
PAINESVILLE, Ohio -- The Ohio Department of Health is analyzing blood samples from 143 horses in Lake County for signs of the West Nile virus.
Surveillance and monitoring efforts for the potentially deadly virus have increased since its presence was confirmed in Ohio last week.
A Lake County homeowner had turned in a dead blue jay that tested positive.
Mosquitoes can carry the virus from birds to humans and other animals. Results on the horse samples are expected by mid-August.
Testing: Two dead blue jays, recently found in Brookfield and Newton Falls, have also been sent by the Trumbull County Health Department to a lab at The Ohio State University in Columbus for testing.
It will be 10 days before test results are available, health officials said.
The Trumbull County Health Department continues to collect mosquitoes four nights a week at locations around the county to be tested for the virus said J. Vincent Catuogno, the director. That program was started at the beginning of the summer.
"The virus can spread so quickly," Catuogno said. "It has no boundaries."
No direct danger: Mosquitoes can transmit the virus to horses, but don't pick it up from them, so the disease isn't a direct danger to humans when it's present in horses, according to Ohio's West Nile Virus Work Group.
"This is simply a precautionary measure," said Fred Dailey, director of the Ohio Department of Agriculture.
Lake County Health Department is increasing mosquito surveillance and checking more dead birds, said spokesman Ed Binic.
The virus has killed nine people in New York and New Jersey since 1999.
No human cases have been reported in Ohio.
The disease, fatal in about 10 percent of infected humans, will kill 30 percent to 40 percent of infected horses.