PHOTO: ADOBE STOCK

The first human case of West Nile virus this year in Allegheny County has been diagnosed in a Plum resident.

The individual began experiencing symptoms of fever, fatigue, diarrhea and other issues in mid-July, according to the Allegheny County Health Department. As a result, the county has set up additional surveillance in the eastern part of the county.

The virus is carried by mosquitoes. In the last week, the county also has been spraying for mosquitoes in the West End neighborhoods of Pittsburgh and Crafton and Ingram. It also has recently detected infected mosquitoes in Wilkinsburg, Schenley Park, Mount Washington, Beltzhoover, Mt. Oliver and Hazelwood. They spray with Zenivex E20, a pesticide that is not harmful to humans or pets; it is delivered in extremely small amounts in a fine mist designed to minimize exposure.

Most people who are bitten by a mosquito carrying the virus do not develop symptoms. But some older people or those with lower immunity can develop headaches, body aches, joint pains, vomiting and other issues. Occasionally it can lead to death; an 80-year-old woman in the Elliott neighborhood of Pittsburgh died in early fall 2023. Before the Plum diagnosis, the last reported human case of West Nile Virus in Allegheny County occurred in September 2024.

The mosquitoes that carry West Nile virus are most active at dawn and dusk, so be sure to wear insect repellent and cover your arms and legs if you’re out at those times. Take a look around your property to make sure there is no standing water; mosquitoes can lay their eggs in or near just a small amount of water, as deep as a bottle cap.