Conditions ripe for mosquito virus

By Tom Venesky - [email protected]
Corpus -

Larry Corpus knows what can happen with mosquito populations when conditions are right.

An assistant biology professor at Misericordia University, Corpus and his students conducted research on mosquito habitat last summer, counting the number of larvae found in various places where stagnant water formed.

The students quickly learned that it doesn’t take much for mosquitoes to thrive.

“We checked a small flower vase in a local cemetery that had water in it. In that single vase, we counted over 800 mosquito larvae,” Corpus said. “They don’t need much.”

On Friday, the state Department of Environmental Protection issued a release cautioning about “record mosquito numbers” and the resulting heightened risk of West Nile virus.

While mosquitoes may not need much in order to thrive, as Corpus says, the factors they do require have been in ample supply this summer.

Receding floodwaters and heavy rains across Pennsylvania have created a perfect storm of conditions, contributing to the highest level of West Nile virus activity in the mosquito population since the disease was first introduced in 2000, according to DEP. The disease has infected more than 150 people in the past six years and is on track to pose an unusually higher than normal risk this year. As of Aug. 1, the virus has been detected in either mosquito samples, birds or both in 51 counties.

Colleen Connolly, community relations coordinator for DEP’s Northeast Regional Office, said as of Friday 2,274 mosquito pools tested positive in the state. At the same time last year there were 1,458 positives. In Luzerne County, 23 mosquito samples have come back positive so far, compared to 65 all of last year.

As a result of the increased threat of West Nile virus, Gov. Tom Wolf’s administration has implemented several specific initiatives. The Pennsylvania Department of Health has issued an advisory through the Health Advisory Network to alert medical professionals about the risk of West Nile virus this year, and the program’s budget has been increased by $140,000.

DEP West Nile virus program staff have conducted multiple operations to reduce mosquito habitats from tire piles and other areas. These efforts will be ongoing until the first hard frost of the year.

Corpus advised that everyone should take steps to eliminate mosquito habitat on their properties, adding that it doesn’t take long for a breeding ground to develop.

“It has to be there just for a little bit for the water to be conditioned. It’s not just the rain that creates mosquito habitat, it’s also the warm and humid weather,” Corpus said. “When you have sunlight striking the water, the organic matter builds rapidly. This is what larvae feed on, and the female mosquito detects this and will lay her eggs.”

While there has been one human case of West Nile virus this year — in Allegheny County — birds are especially susceptible. There have been 23 avian cases of the virus this year and the state bird, the ruffed grouse, has been hit hard, according to DEP.

Symptoms of West Nile virus in humans are typically like those of a mild flu, but the virus can lead to a more serious condition that includes swelling of the brain, muscle convulsions, coma, paralysis and death. Since DEP first began monitoring for the virus in 2000, there have been 33 fatal cases of West Nile in Pennsylvania.

Abundant rainfall and warm, humid weather may create a boom in mosquito numbers

By Tom Venesky

[email protected]

Reach Tom Venesky at 570-991-6395 or on Twitter @TomVenesky

Reach Tom Venesky at 570-991-6395 or on Twitter @TomVenesky