Erie County reports 2024's first batch of West Nile-infected mosquitoes

West Nile Virus-infected mosquitoes have been trapped in Erie County for the first time in 2024.

The batch was found in Millcreek Township, the Erie County Department of Health reported Thursday. Exact locations are not provided.

County health officials have found the virus in mosquitoes or birds nearly every summer since 2000, a year after West Nile was first detected in the United States. The only years without a documented West Nile case in Erie County were 2010 and 2017, according to the Pennsylvania Department of Environmental Protection.

But a feared epidemic of human West Nile cases has not materialized. Only nine county residents have tested positive for West Nile, and none since 2018.

West Nile Virus can cause brain swelling in rare cases

West Nile remains a health concern for humans, however, because the virus can cause encephalitis — a life-threatening swelling of the brain. Less than 1 percent of West Nile infections lead to encephalitis, but the death rate for West Nile encephalitis is about 9 percent, according to Penn State Extension.

No mosquitoes trapped in Erie County so far this year have tested positive for Jamestown Canyon Virus, another mosquito-borne illness that can, in rare cases, cause encephalitis. One mosquito batch trapped in Crawford County in 2024 has tested positive for JCV.

Who is most at risk of West Nile and Jamestown Canyon complications?

Certain people are more at risk of West Nile and Jamestown Canyon complications than others. They include those older than 60, people with weakened or compromised immune systems, and those with chronic diseases like diabetes and high blood pressure.

Precautions you can take to prevent mosquito bites

If you fall into one or more of those categories, it's recommended that you take precautions to reduce your risk of mosquito bites when heading outdoors, especially between dusk and dawn. These include using insect repellent, and wearing long pants and a long-sleeved shirt.

Contact David Bruce at dbruce@timesnews.com. Follow him on X @ETNBruce.