New York health officials say they have detected the virus which causes polio in the city's wastewater.

New York City and state health authorities said on Friday the discovery suggests the virus may be circulating locally.

Polio infects mostly infants and toddlers and can cause permanent paralysis of the arms and legs. As the disease is often asymptomatic, officials suspect it may have been excreted by people who don't realize they have been infected.

The investigation began after a polio case was reported in New York state last month. The disease had not been confirmed in the United States since 2013.

Polio infection can be prevented by a vaccine. But in some parts of New York state, the inoculation rate of two-year-olds is around 60 percent. Health officials are urging those who are unvaccinated to get their shots.

Data from the World Health Organization and others show polio has been largely eradicated since the introduction of the vaccine. But the virus was recently detected in sewage in the British capital of London.