Bald Eagle

West Nile virus threat spurs mosquito spraying near Clarence

The good news: There are fewer confirmed cases of West Nile virus in Centre County this year than last.

The bad news: There are a lot more mosquitoes.

The hot, wet July weather has spawned a rash of the blood-sucking pests, and the Pennsylvania West Nile Control Program has deemed a few infected mosquitoes enough of a threat to spray and hopefully eradicate that threat.

Centre County mosquito control officials have confirmed three infected mosquitoes in the Snow Shoe Township area in late July, said Amanda Witman, press aide with the state Department of Environmental Protection in Harrisburg. Another infected mosquito was found in Spring Township on July 25.

The rash of mosquitoes from the wet, humid July yielded the increase in testing.

“We ramp up surveillance in that area to see if there’s a significant problem,” Witman said. “If we find the virus that could potentially impact human health, we will spray.”

Most of Centre County has been virus-free, but Clarence-area residents near Snow Shoe may hear the trucks with mosquito-spraying equipment in the neighborhood from about 8:30 to 10 p.m. Wednesday. Should it rain, the spraying will be pushed back to Thursday, according to a Centre County West Nile virus program news release.

So far this year, Centre County has seen just the four positive West Nile virus cases, and that’s from a sample of 232 tested, Witman said.

However, we are still in the middle of the mosquito season, which runs May to October, she said.

“Still, I would be surprised if we saw another four cases — for a total of eight all year,” she added.

That’s because the cool and dry spring this year kept mosquitoes at bay.

Here’s how it works: Mosquitoes breed and feed, and when they feed on birds, they can become infected with the virus.

“The birds are the real culprit,” Witman said, “even though the mosquitoes spread the virus.”

Last year, there were 52 positive cases of West Nile in Centre County alone, she said, and that’s out of 425 samples. For the record, 24,000 samples were tested statewide last year with slightly more than 4,300 positive cases.

The difference was that in 2012, spring was warm and wet. Therefore mosquito breeding happened earlier and more rapidly but with fewer of the insects.

When the mosquitoes produce earlier, they tend to infect the younger avian population, Witman said, and those younger birds are more vulnerable than adult birds to the virus.