YORK – York High School is taking no chances after the deaths of two horses from Eastern equine encephalitis in York County.

Athletic Director Ted Welch made three schedule changes and called off some games Thursday and Friday. The starting times of many games were changed to avoid having players on fields at dusk, when mosquitoes are more active.

“We’re trying to use common sense to arrange the schedules properly and to err on the side of caution,” Welch said.

So far, no other York County schools have followed suit.

Dr. Dora Mills, the state public health director, said Wednesday that the death of two horses is “a further indication that the risk to people of contracting the infection is present, at least in southern Maine.”

The virus is spread by mosquitoes.

So far, no humans have been diagnosed in Maine but two horses died from the virus last week in York and Lebanon.

In New Hampshire, several schools including those in Dover, Plaistow and Hopkinton, moved start times for games to the afternoon after the death of Kelly Labell, a Newton, N.H., woman who died of the virus.

At Marshwood High School in South Berwick, Athletic Director Rich Buzzell said the possibility of games being postponed has been discussed, but no action has been taken.

At Sanford High School, Athletic Director Gordon Salls said his school’s athletic schedules will remain the same. “We haven’t seen any problems in this area,” Salls said. “Right now, the games are at the same time.”

Meanwhile, horse owners are checking their animals’ vaccinations records.

Veterinarian David Jefferson of Maine Equine Associates in New Gloucester said his practice has been receiving a steady stream of calls from worried horse owners, asking whether their animals are safe.

“It’s a nasty disease,” he said, noting that sick animals can show symptoms such as loss of coordination and seizures.