New York health officials on Thursday reported a polio case, the first in the U.S. in nearly a decade.
Officials did not immediately offer details on who the Rockland County resident was, whether the person was vaccinated or their current condition.
State officials said it appeared the person had a vaccine-derived strain of the virus, perhaps from someone who got live vaccine — available in other countries, but not the U.S. — and spread it.
Polio was once one of the nation's most feared diseases, with annual outbreaks causing thousands of cases of paralysis — many of them in children.
Vaccines became available starting in 1955, and nationwide vaccination campaign cut the annual number of cases to less than 100 in the 1960s and fewer than 10 in the 1970s, according to the CDC.
In 1979, polio was declared eliminated in the U.S., meaning there was no longer routine spread of the virus in the country. Rarely, travelers with polio have brought infections into the U.S., with the last such case in 2013.
U.S. children are still routinely vaccinated against polio. Federal officials recommend four doses: to be given at 2 months of age; 4 months; at 6 to 18 months; and at age 4 through 6 years. Some states require only three doses.
According to the CDC's most recent childhood vaccination data, about 93% of 2-year-olds had received at least three doses of polio vaccine.
Polio spreads mostly from person to person or through contaminated water. It can infect a person's spinal cord, causing paralysis and possibly permanent disability and death. The disease mostly affects children.
Polio is endemic in Afghanistan and Pakistan, although numerous countries in Africa, the Middle East and Asia have also reported cases in recent years.
Last month, health officials in Britain warned parents to make sure their children have been vaccinated after the polio virus was found in London sewage samples. No cases of paralysis were reported.
Additional reporting by The Associated Press.