Allegheny County Health Department Confirms Additional West Nile Virus
Published on September 08, 2025
Allegheny County Health Department Confirms Additional West Nile Virus in Mosquitoes
Nine Neighborhoods Scheduled for Spraying on September 10
PITTSBURGH – The Allegheny County Health Department (ACHD) has confirmed that additional mosquito samples have tested positive for West Nile Virus (WNV). A second human case of WNV has also been reported from Pittsburgh’s North Side.
To reduce the risk of human transmission, ACHD will conduct mosquito control treatment in the following neighborhoods: Brighton Heights, Marshall-Shadeland, California-Kirkbride, Manchester, Allegheny Commons, the Mexican War Streets, Perry South, Fineview, and Troy Hill/Spring Garden.
Treatment will involve the use of Zenivex E20, an insecticide approved by the Pennsylvania Department of Environmental Protection. Zenivex is one of the safest insecticides available because it works on contact with mosquitoes yet degrades rapidly in sunlight.
The insecticide is applied using ultra low volume (ULV) sprayers to minimize exposure to 0.6 ounces per acre. This application process is considered low risk to people, pets, wildlife, and pollinators. Crews will conduct spraying using truck-mounted ULV equipment on Wednesday, September 10, from 7:30 p.m. to 11:00 p.m. If weather prevents spraying on that date, the work will be rescheduled for Thursday, September 11, during the same time frame.
“Mosquitoes that carry West Nile Virus are most active from dusk to dawn,” said Nicholas Baldauf, ACHD Vector Control Specialist. “We encourage residents to wear insect repellent or long sleeves and pants when outdoors, especially during these times.”
West Nile Virus is the most common mosquito-borne disease in the United States. It is a vector-borne disease which means it is transmitted through the bite of infected mosquitoes. While there is no vaccine for WNV, according to the CDC, 70–80% of people infected with West Nile Virus do not develop symptoms. However, about 20% may develop fever, headache, body aches, vomiting, or rash. Severe illness is rare but can occur in less than 1% of cases. Individuals who believe they may be infected should contact a health care provider for evaluation and care.
“Allegheny County residents play an important role when it comes to reducing the area’s mosquito population,” said Baldauf.
Mosquitoes can breed in as little as half an inch of stagnant water, often found in items such as tires, buckets, clogged gutters, unused swimming pools, and corrugated piping.
To report mosquito breeding sites, residents can contact the ACHD Housing and Community Environment Program at 412-350-4046 or submit a complaint online.
Learn more about Vector-Borne Diseases in Allegheny County.
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The Allegheny County Health Department's mission is to protect, promote, and preserve the health and well-being of the more than 1.2 million people who call Allegheny County home.
Media inquiries may be directed to Ronnie Das,
Public Information Officer for the Health Department,
at ronnie.das@alleghenycounty.us or by phone at 412-578-7991.