August 04, 2025
Ken Ruinard/USA TODAY NETWORK via Imagn Images
Wister Woods and Wakefield Park in Germantown are being sprayed with insecticide Monday to kill mosquitos potentially carrying West Nile virus, Philadelphia health officials say.
To prevent the spread of West Nile virus, the Philadelphia Department of Health is spraying parts of Germantown with a mosquito insecticide Monday night.
The city's Vector Control staff will apply the treatment around dusk in Wister Woods and Wakefield Park. Mosquito samples from the area have shown that adult mosquitos potentially carry the disease, so the spraying is a preemptive measure.
Only certain species of mosquitos carry the West Nile virus, which can cause encephalitis — inflammation of the brain — when transmitted to humans. There are more than 3,000 mosquito species worldwide, but only 200 in the United States and 60 in Pennsylvania. In urban areas, the most common species is the northern house mosquito, which is thought to transmit the most West Nile cases in Pennsylvania, according to Penn State Extension.
Mosquitoes infected with West Nile virus have detected this summer at several places in Philadelphia, including Pennypack Park. They also have been detected in Bucks, Chester, Delaware and Montgomery counties, and in Burlington, Camden and Gloucester counties in parts of South Jersey. No human cases have been reported in the Philadelphia region.
During the spraying, a chemical treatment called Duet Duel Action Adulticide will be distributed in small aerosol droplets by a machine mounted to a truck. The mist stays in the air and kills the bugs on contact. It has no residual effects, according to the health department, and quickly evaporates.
People can prevent mosquito bites by using insect repellent, wearing long sleeves and pants, and staying indoors at dawn and dusk — when mosquitos are most active.
Most people infected with West Nile virus do not develop symptoms, but about 1 in 5 develop a fever or other symptoms, including headache, joint pains, vomiting, diarrhea and a rash. About 1 in 150 people develop more serious illnesses.
People 55 and older, people who have received organ transplants and those with underlying medical conditions like cancer, diabetes, high blood pressure and kidney disease are more susceptible.
