Delco health department finds mosquitos with West Nile virus for first time this summer

West Nile virus has been detected in mosquitos for the first time this summer in Delaware County, the county’s health department announced last week.

West Nile virus, the leading cause of mosquito-borne diseases in the continental U.S., spreads to humans through mosquito bites. According to the Centers for Disease Control and Prevention, most people infected with the virus won’t develop any symptoms. About one in five infected individuals will develop a fever, along with possible headaches, body aches, joint pains, vomiting, or diarrhea. About one out of 150 people develop a severe or fatal illness.

“Overall it typically does not cause significant disability or poor health outcomes unless someone is immunocompromised or they have comorbidities that may be causing them to be more at risk for these infections,” said Delaware County’s Director of Public Health, Melissa Lyon.

In May, West Nile virus was identified in mosquitos within Philadelphia County. This year, the virus has also been found in Montgomery, Chester, Bucks, and now Delaware counties. On Tuesday, a Pittsburgh-area resident was hospitalized with Allegheny County’s first human case of the virus.

Each year, the virus is found in mosquitos across Pennsylvania from May through October when the insect is active. Following the first frost of winter, mosquitos die off or go dormant til the following spring.

“Regionally, you will almost always have a case of West Nile virus in a human each year,” Lyon said. “There may be times that Delaware County or Bucks County doesn’t have a positive case, but there’s always a slight risk for human transmission in the Southeastern Pennsylvania region.”

There is no vaccine or cure for West Nile virus, so the best way to protect against the virus is by preventing mosquito bites altogether. The Inquirer published a guide on how to prevent and recover from West Nile virus and Lyme disease, which is passed on by blacklegged ticks, or “deer ticks,” commonly found throughout Pennsylvania.

To prevent West Nile virus-infected mosquito bites, wear light long-sleeved shirts and pants when out in nature or near water sources and use bug spray with at least 20% DEET. Eliminating mosquito breeding grounds, like sources of standing water, overgrown shrubs, and tall grass, will help control the nearby mosquito population.

Staff writers Abraham Gutman and Aubrey Whelan contributed to this article.