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Second Case Of West Nile Virus Reported In Allegheny County


In the fleeting days of summer, health officials reported two cases of West Nile virus in Allegheny County, prompting its health department to monitor their condition and inspect the area around their homes for further cases.

West Nile virus is spread through bites from infected mosquitos.

While we more often think about mosquito bites in the summer, it is more common for West Nile to present itself in humans in the fall.

“It’s more typical that we do see them later in the season in part because it can be as much as a two-week period of time between the bite and symptoms occurring,” said Karen Hacker, director of the Allegheny County Health Department.

Birds are the most common carrier of the virus, but mosquitos pass the virus by biting an infected bird and then biting a non-infected bird. When birds migrate south in the fall, mosquitos are more likely to bite and infect humans. The shift in feeding patterns and the sometimes weeks-long incubation period for West Nile in humans explains much of the increase in cases in the fall, Hacker said.

Symptoms can include fever, headache or body aches. Some report a rash, swollen lymph glands in the last few days of the illness. More serious symptoms include tremors, convulsions and muscle weakness.

“Less than one percent of people who are infected with the West Nile virus will develop those neurological complications,” Hacker said.

There have been 24 cases of West Nile reported in Pennsylvania this year, up from 13 in 2014. The last West Nile death in Pennsylvania was reported in 2013 in Bucks County, according to the Pennsylvania West Nile Virus Control Program website.

There is no cure for West Nile, but Hacker said advancements in health care and awareness have helped to keep outbreaks under control.

“I do think that now people at least know the symptomology so they can test for it.”  

Standing water is the most common breeding ground for mosquitos that carry West Nile. To avoid bites, the Health Department suggests wearing protective clothing, spraying insect repellant, and avoiding outdoor activities at dawn and dusk.