https://apnews.com/4ca5cf5320d40093ef6eac2ee054f891

NEW YORK (AP) — Philadelphia and Oakland County, Michigan, are joining the small list of U.S. localities that are looking for signs of polio infections in sewage, U.S. health officials said Wednesday.

The Centers for Disease Control and Prevention said the communities will test for polio in sewage for at least four months. Communities in New York state began testing earlier this year after a man was diagnosed with paralytic polio outside New York City.