The United States reported its first polio case in nearly a decade on Thursday.
The New York State Health Department said a person living in Rockland County, 30 miles north of Manhattan, 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 originate from a location outside of the United States where OPV is administered, as revertant strains cannot emerge from inactivated vaccines,” the New York Department of Health said in a statement. .
Officials warned health care providers to be on the lookout for more cases and urged people in the area who are unvaccinated to get vaccinated.
Over the past few decades, a massive global effort has nearly eliminated poliomyelitis, a debilitating and life-threatening viral disease that primarily affects children under the age of five.
Cases have fallen by 99% since 1988, when poliomyelitis was endemic in 125 countries and 350,000 cases were recorded 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 poliomyelitis in America were reported in 1979.
OPV replicates in the gut and can be passed to others via water contaminated with faeces, which means it will not harm the child who has been vaccinated, but it could infect neighbors in places with low levels of sanitation and vaccination.
Although weaker than wild poliovirus, which now only exists 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