The 2013 mosquito season, which usually continues through mid-September, is much calmer than last in terms of the detection of West Nile virus in York
The 2013 mosquito season, which usually continues through mid-September, is much calmer than last in terms of the detection of West Nile virus in York County. (AP File Photo/Wilfredo Lee)

Mosquito season bites, but this year is much calmer than last in terms of the detection of West Nile virus in York County.

So far, there have been four positive samples collected in York County. This time last year, 45 samples tested positive for the virus. Two years ago, that number was 16.

This year's positive samples were found on July 9 in Springettsbury Township, July 11 in Hanover, July 17 in Manchester Township and July 18 in West Manchester Township.

For the past two years, York ranked first in the state in positive samples collected over the year. Last year, the area ranked third in the nation with 389 positive tests for the virus.

The county is typically in the top five statewide, said Tom Smith, West Nile Virus Program administrator for Penn State's Cooperative Extension. It's tied for fifth so far this season; Delaware County tops the list with nine positive samples.

'Normal year': The mosquito season usually continues through mid-September, and maybe into mid-October if the weather cooperates, Smith said.

But for positive samples, he said this year is back to typical numbers after last year's rough season.

"This is more of a normal year for West Nile virus," he said.

But it might seem like the blood-suckers are really biting recently.

That's because mosquito populations have increased because of two factors: the weather patterns and people's negligence in cleaning up water-holding mosquito breeding grounds, such as tires, buckets and kiddie pools, he said.

Mosquitoes love hot, wet and humid weather, Smith said, which are precisely the words to describe most of this July in York. And because people don't clean up, they'll just keep reproducing, he said.

"This is self-inflicted," Smith said.

West Nile: The West Nile virus is always in the area because it exists in the bird population, Smith said. But certain species of mosquito like to feed on birds, he said, so that's why it becomes a concern during the summer.

The virus, first detected in North America in 1999, can cause fever, meningitis and even death in humans, according to the Centers for Disease Control and Prevention. There were three reported human positives in York

County last year.

To decrease the human risk of disease, the West Nile Virus Program conducts spray events across the county that kill adult mosquitoes flying in the area, Smith said.

There were 21 separate sprays last year, he said, and two have been conducted this year in Hanover and Spring Garden Township.

Two more spray events are scheduled in Hanover on July 31 and Aug. 1.

The program will probably announce new sprayings at the end of this week, but they're not the real solution, Smith said.

"Spraying only provides temporary relief," he said. "If people don't clean up, high populations will be back in a week."

--Reach Mollie Durkin at mdurkin@yorkdispatch.com.