Mosquito samples collected by Penn State Extension staff on June 20 in New Salem and June 21 in Dover Township have tested positive for West Nile virus by the Pennsylvania Department of Environmental Protection.

For 2012, six mosquito collections have tested positive for West Nile Virus in York County.

The sample collected in Dover Township had two different mosquito species test positive. Additional surveillance and mosquito trapping in New Salem and Dover Township is being performed by Penn State Cooperative Extension staff and PA DEP staff.

Certain species of mosquitoes carry West Nile virus, which, when transmitted to people, can cause West Nile encephalitis, an infection that can result in an inflammation of the brain. According to the Centers for Disease Control and Prevention, all residents of areas where virus activity has been identified are at risk of getting West Nile encephalitis.

Eliminating sources of stagnant water is the best method to reduce mosquito populations that can transmit West Nile virus. Rain barrels need to be completely screened. Ornamental ponds and fountains need to be stocked with fish or treated with a bacterial larvicide available at most hardware stores.

Twenty one counties in Pennsylvania have now collected mosquito samples testing positive for West Nile. There have been human cases of West Nile Virus every year in York County since 2002.


For more information about reducing mosquitoes in York County call the Penn State Cooperative Extension - York County West Nile Program office at 717-840-2375.

For information about West Nile Virus symptoms in humans, contact the Department of Health at 1-877-PA-HEALTH, or visit the PA State West Nile web site at