Mosquito Spraying To Avert West Nile Virus In Phoenixville Area

This story was updated at 11 a.m. on Aug. 24 to add details about the mosquito tests in Chester County.

PHOENIXVILLE, PA — After multiple mosquito samples in the Phoenixville area tested positive for West Nile Virus, portions Phoenixville Borough and Schuylkill Township will be sprayed, the Chester County Health Department said on Monday.

The Health Department reported for the month of August, nine mosquito sample pools have been analyzed, of which, seven tested positive for West Nile Virus. A total of 819 mosquitoes were collected during this time.

"The low number of mosquitoes and high number of positives show the concentration of positive mosquitoes is high," a spokesperson for the County Health Department said on Tuesday.

The Health Department said it will conduct a mosquito control treatment spray in portions of Phoenixville Borough and Schuylkill Township on Aug. 25 from 7:30 to 11 p.m. The rain date is Aug. 26 at the same time.

A map of the area where the mosquito control treatment is being sprayed is shown at the end of this story. People who are concerned about exposure to mosquito control products can reduce their potential for exposure by staying indoors with children and pets when their neighborhood is being sprayed, the Health Department said.

The Chester County Health Department explained it conducts mosquito control treatment in areas with high levels of mosquito activity and where multiple mosquito samples have tested positive for West Nile Virus (WNV).

"After exhausting other available mosquito control strategies, spraying is conducted to reduce residents' risk of WNV infection," the CCHD said in a news release.

The Health Department said anyone living in an area where mosquitoes are infected with WNV is at risk, but the risk of infection is highest for people who work outside or participate in outdoor activities.

Fewer than 1 percent of people infected will develop serious illness. While serious illness can occur in people of any age, people over 60 years of age, people who have received organ transplants, and people with certain medical conditions such as cancer, diabetes, hypertension, and kidney disease are at the greatest risk for serious illness, the Health Department explained.

The Chester County Health Department said it uses a truck-mounted sprayer to apply 3.0 ounces of U.S. Environmental Protection Agency-approved product (Zenivex E4 RTU) per acre of land.

The mosquito control spray becomes inactive in just a few hours or with sunshine. Sprays are conducted after sunset when mosquitoes are most active and bees have returned to their hives.

Sprayers are turned off near bodies of water and apiaries to protect aquatic life and bees, the Health Department said.

The Chester County Health Department notifies registered beekeepers and residents who are listed as hypersensitive in a designated spray area prior to conducting a spray.

"If you would like to take extra precautions after the spray is completed, you can rinse off outdoor furniture or playground equipment before use," the news release said.

While spraying helps to reduce mosquito populations, the Chester County Health Department also encourages residents to take action on their own properties to make it a "Bite-Free Zone." Detailed instructions can be found here.

The Chester County Health Department is a member of the Environmental Protection Agency’s Pesticide Environmental Stewardship Program. This program requires participants to affirm that environmental stewardship is an integral part of their integrated pest management (IPM) practice, use current, comprehensive information regarding the life cycle of mosquitoes within their IPM program, educate the community on the benefits of IPM, and demonstrate a commitment to pesticide risk reduction activities, the Health Department explained in its news release.

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