The heavy rainfall last week didn't help as counties across the Delaware and Lehigh valleys report mosquito pools positive for West Nile.
At CareStat in Havertown, Dr. Jonathan Gusdorrf said they have already seen a human case.
"What we do know for sure is that patient was infected with a recent West Nile virus," said Dr. Gusdorff.
What they don't know is exactly where he picked it, because the patient visiting from out-of-state.
State labs still need to confirm the clinic's lab result.
This doesn't mean there is cause for alarm, so now is the time to take precautions, such as:
-Use mosquito repellent
-Wear long sleeves and pants if out at dawn or dusk
-Get rid of standing water
Only about 20 percent of people infected will get symptoms, but some groups have to be especially careful.
"The ones who are at the greatest risk for severe disease would be kindergarten age or younger and some of our senior citizens 65, 70 and older," said Dr. Gusdorff.
Common symptoms of West Nile include headache, fever and fatigue. Signs of a rare but serious illness also include muscle weakness and stiff neck.