The United States reported its first case of polio in nearly a decade on Thursday.
The New York State Department of Health said a person living in Rockland County, 30 miles (48 kilometers) north of Manhattan, had tested positive for the disease.
America last recorded a case of polio in 2013, according to the Centers for Disease Control and Prevention.
The latest case was a type “indicative of a chain of transmission from an individual who received the oral polio vaccine (OPV),” officials said.
The oral vaccine was discontinued in the United States in 2000.
“This suggests that the virus may have originated at a site outside the United States where OPV is administered, since revertant strains cannot arise from inactivated vaccines,” the New York health department said in a communicated
Officials warned health care providers to be on the lookout for more cases and urged people in the area who are not vaccinated to get the vaccine.
In recent decades, a massive global effort has moved closer to ending polio, a crippling and potentially fatal viral disease that mainly affects children under the age of five.
Cases have declined by 99 percent since 1988, when polio was endemic in 125 countries and 350,000 cases were reported worldwide.
In the United States, cases declined dramatically in the late 1950s and early 1960s after a vaccine was developed.
The last natural cases of polio in the United States were reported in 1979.
OPV replicates in the gut and can be passed to others through faecal-contaminated water, meaning it won’t harm the child who has been vaccinated, but could infect neighbors in places where levels of hygiene and immunization are low.
Although weaker than wild poliovirus, which now exists only in Afghanistan and Pakistan, the variant can cause severe illness and paralysis in people not vaccinated against the disease.
Last month, the World Health Organization and British health officials said a vaccine-derived type of poliovirus had been detected in sewage samples from London.
© Agence France-Presse