West Nile virus infections reported in 7 Westmoreland communities

West Nile virus has been detected in five more Westmoreland County communities as high levels of the virus are being found across the state.

Since Aug. 7, mosquitoes have tested positive for the virus in Youngwood, Midway, Scottdale, Trafford and New Kensington — joining infected insects sampled earlier this season in the Latrobe and Greensburg areas, according to Chrissy Edwards-McCune, West Nile virus technician with the Westmoreland Conservation District.

There have been no reports of the virus spreading to humans so far this year in Westmoreland County. But Edwards-McCune noted mid-August to mid-September historically has been the peak time for such infections from mosquito bites.

“Very high levels of West Nile virus are being found across the commonwealth,” she said. In Westmoreland, she added, “Adult mosquito control (spraying) may be considered in some areas if virus activity continues to be high after additional mosquito testing is completed.”

So far this year, she said, the county virus program has concentrated on eliminating mosquito larvae at sites where the pests were found to be breeding. She set additional mosquito traps in those areas to determine how widely the virus has spread.

She has set 238 traps in the county this year and has collected 11 positive mosquito samples — some occurring multiple times in the same areas.

According to statewide data, West Nile virus has appeared so far this year in all but 17 of Pennsylvania’s 67 counties. In the southwestern corner of the state, Armstrong, Fayette and Butler counties are among the few where the virus hasn’t been detected.

Sampling across the state has revealed a total of 1,908 positive mosquito samples. That includes 135 in Allegheny County, 36 in Beaver County, 14 in Washington County, 13 in Cambria County and seven each in Fayette and Indiana counties. Philadelphia leads the way with 325 positive samples.

West Nile infections have been reported in 10 people, including two in Allegheny County.

In 2023, Pennsylvania reported 22 cases of human infection — including four that proved fatal, one of them in Allegheny County.

Scientist say rising global temperatures associated with climate change are creating an extended mosquito season in much of the United States, increasing the potential risk of human exposure to West Nile and other diseases spread by the insects.

In Pennsylvania, from 1980 through 2009, there was an annual average of 110 days with conditions suitable for mosquito activity, according to a Washington Post report. Those conditions (temperatures between 50 and 95 degrees and average humidity of at least 42%) were present for a yearly average of 124 days from 2019 through 2023 in the Keystone State.

To limit the chance of getting bitten, Edwards-McCune recommends staying inside at dusk and dawn, when mosquitoes are most active.

“If the public chooses to be outside, they should wear pants and long-sleeved shirts and/or mosquito repellents,” she said.

Eliminating areas of standing water will keep mosquitoes from breeding around one’s home.

“Mosquito larvae need water to complete their life cycle, and they take only five to seven days to become adults,” she said. “Mosquitoes can breed in just a capful of water.”

The Centers for Disease Control and Prevention offers more information about West Nile virus.