This is a huge problem in Texas right now and we are starting to see more cases here as well.
A map released by the Pennsylvania Health Department shows the Lehigh and Delaware Valleys in the red zone - most at risk.
There are three more confirmed cases of West Nile virus reported in Pennsylvania, including two men from Delaware County.
They both developed meningitis from the virus.
Action News is told they are now recovering.
Some people who are infected will have no symptoms or notice just a mild illness.
But about 20-percent will develop a more severe illness with a fever.
Less than 1-percent will get a very severe illness with meningitis or encephalitis, which is swelling to the brain or spinal cord
The people who are most at risk are anyone over the age of 50 and anyone with a compromised immune system.
Still, everyone should take precautions:
More information on West Nile virus including guidelines on using repellent on children: