New York, New York - Polio has been detected in New York City, the state Health Department said Friday, a startling discovery based on wastewater samples that comes three weeks after the first confirmed US case since 2013 emerged in Rockland County.

The US went almost a decade without logging any polio cases, but the reported arrival of the paralyzing virus in New York City suggests community spread.

"For every one case of paralytic polio identified, hundreds more may be undetected," Dr. Mary Bassett, the state health commissioner, said in a statement. "The detection of poliovirus in wastewater samples in New York City is alarming, but not surprising."

Health officials are still trying to determine exactly how the infections came about. "Already, the State Health Department – working with local and federal partners – is responding urgently, continuing case investigation and aggressively assessing spread," Bassett added.

Dr. Ashwin Vasan, the city health commissioner, urged New Yorkers to respond to the news by getting jabbed with the long-administered polio vaccine.

"The risk to New Yorkers is real but the defense is so simple – get vaccinated against polio" Vasan said in a statement. "Polio is entirely preventable and its reappearance should be a call to action for all of us."

According to the Cleveland Clinic, the extremely contagious virus may not cause symptoms in most people, it can lead to paralysis in those who become seriously ill. There is no known cure for polio.