The origin of the virus is still under investigation, but samples in New York are genetically linked to polioviruses found in London and Jerusalem wastewater.
The polio virus has now been found in seven wastewater samples in Rockland and Orange counties, which are next to each other and north of New York City.
New York state health officials issued a more urgent call on Thursday for unvaccinated children and adults to get inoculated against polio, citing new evidence of “potential community spread” of the debilitating virus.