West Nile virus found in Allegheny County mosquitoes

Mosquitoes collected by the Allegheny Health Department in Mt. Oliver Borough and in the nearby Pittsburgh neighborhoods of Beltzhoover and South Side Slopes have tested positive for West Nile virus.

The infected mosquitoes were collected on July 11 as part of the department’s Vector Control Program. County health officials said they will continue to set mosquito traps as they monitor for the virus and other diseases that are carried by the insects.

The department announced in early June its plan to use pesticides to treat about 10,000 stormwater catch basins in areas of Pittsburgh with a history of West Nile virus activity. It planned to use FourStar, a product designed to kill mosquito larvae without harming people, pets and aquatic life.

Each spring, the department also treats wetlands that are known mosquito breeding sites.

West Nile virus is the leading cause of mosquito-borne disease in the United States.

The most recent human case of West Nile virus was reported last September.

According to the Pennsylvania Department of Environmental Protection, there were 34 human cases of the disease recorded last year among 12 counties, including 11 cases in Philadelphia, three in Allegheny and one fatal case each in Franklin, Lancaster and Philadelphia counties.

Also last year, 2,817 mosquito samples collected from among 50 counties tested positive for the virus. That included 137 samples from Allegheny County and 10 from neighboring Westmoreland County.

One in five people infected with the virus develop a fever and other symptoms, such as headache, body aches, joint pains, vomiting, diarrhea or a rash, according to Allegheny health officials. Less than 1% of infected people develop a serious illness.

Cases of West Nile virus occur during mosquito season, which starts in the summer and continues through fall. There is no vaccine for the virus or medication to treat it.

Nicholas Baldauf, vector control coordinator for the Allegheny County Health Department, advised residents to wear long sleeves and pants and use insect repellent on exposed skin to help avoid mosquito bites. Mosquitoes are most active around sunrise and sunset, he said.

“Mosquitoes can breed in as little as a half inch of water, so residents should pay close attention to potential breeding sites like stagnant water in tires, unused swimming pools, buckets and clogged gutters,” Baldauf said.

Allegheny County residents can report mosquito breeding sites on private or public property by calling 412-350-4046.