Pennsylvania Confirms Additional West Nile Virus Cases

Ruzanna Harutyunyan's picture

The Pennsylvania Department of Health today announced three newly confirmed cases, and one suspected case, of West Nile virus infection in southeastern Pennsylvania. This brings the number of cases reported in Pennsylvania this season to five.

The four new cases involve people ranging in age from 48 to 66 and they occurred in Philadelphia, Delaware (2), and Bucks counties between Aug. 8 and Aug 18, which is before the time the Department of Environmental Protection administered aerial treatments to control mosquitoes in the southeastern part of the state (Aug. 26-27).

DEP sprayed the region after finding evidence that the proportion of mosquitoes infected with West Nile virus was rising. Testing done after the aerial treatments showed mosquito populations were reduced by about 80 percent.

“The Department of Health remains concerned about the risk of West Nile virus for Pennsylvania residents, particularly people in southeastern PA,” said Secretary of Health Dr. Calvin B. Johnson. “The recent spraying in the Philadelphia area was a necessary measure to reduce the threat of human illness from West Nile virus and is likely to have prevented additional cases.”

Disease from West Nile infection can take two forms. The milder form, known as West Nile fever, usually results in headache, body aches, skin rash, and swollen lymph glands accompanied by fever. The more severe form is known as West Nile encephalitis (an inflammation of the brain). People with encephalitis may experience high fever, headache, neck stiffness, disorientation, a decreased level of alertness, tremors, seizures, paralysis, and coma. Anyone with these symptoms should immediately contact his or her health care provider.


There is no specific treatment for West Nile virus. For severe cases, hospitalization is needed and illness can be associated with long-term disabilities and death.

Since it was first identified in Pennsylvania in 2000, West Nile virus has been found in all areas of the state and has returned each summer. Pennsylvanians should presume that West Nile virus is present throughout the state during the warmer periods of the year and should take appropriate precautions.

While late summer is the peak period for West Nile virus infection, it remains a public health risk as long as warm weather persists in the fall. Mosquitoes will continue to be present and to bite until the first frost occurs in late autumn. The public is urged to continue to take steps to avoid mosquito exposure and to reduce the presence of mosquitoes around the home.

To eliminate mosquito breeding sites, the public is urged to look for areas of standing water or sluggish water flow, including clogged gutters and drains, trash can lids and other plastic vessels, stagnant swimming pools, and garden planters.

To avoid mosquito bites, use DEET-containing insect repellant during outdoor activities, especially in the evening during peak mosquito activity. Wear long sleeves and pants outside. Make sure that window screens are in place and intact.

People at highest risk of severe West Nile virus infection (the elderly and persons with compromised immune systems) should consider avoiding outdoor activities during early morning and at night.

The commonwealth will continue to monitor mosquito populations to determine whether additional pesticide applications will be necessary to reduce the risk of additional human illness.