The Centers for Disease Control and Prevention (CDC) has reportedly sent a team to New York to investigate a case of polio.
It was detected in person in Rockland County.
A spokesperson for the CDC told ABC News that the agency is assisting with wastewater testing and vaccination efforts.
According to the CDC, polio has essentially been eliminated in the U.S. since the 1970s.
"This means that there is no year-round transmission of wild poliovirus in the United States," the agency says.
There is no cure for the highly-contagious disease, which can cause lifelong paralysis. However, the CDC said it can be prevented with vaccines, which are routine in children.
New Yorkers who were not vaccinated as children are being encouraged to get the vaccine. State health officials say they have vaccinated hundreds of people since the case of polio was first detected in July.