Health officials say they have identified poliovirus in New York City sewage, suggesting local transmission of the virus.

This finding comes after a case of paralytic polio was found in a Rockland County resident on July 21.

The illness can lead to permanent paralysis of the arms and legs and even death in some cases, according to the New York City Health Department.

Although both city and state health officials say there is a high polio vaccination rate, they are still urging people who haven’t received the vaccine to do so immediately.

Officials with the Centers for Disease Control and Prevention also warn this case could be the tip of iceberg and could lead to more cases.

"It is imperative that all New Yorkers make sure they have received their full polio vaccination, which is standard for children and nearly 100% effective,” stated City Council Speaker Adrienne Adams and Health Committee Chair Lynn Schulman.

The World Health Organization says 90% of people who have polio do not have any visible symptoms.

"Most of the time you don't get sick, it’s 4%, so it’s a smaller percentage that end up with paralysis. If you have it in the water, it means it is circulating in the community,” said Dr. Margaret Hammerschlag, professor of pediatrics and medicine at SUNY downstate.

“For every one case of paralytic polio identified, hundreds more may be undetected,” state Health Commissioner Dr. Mary T. Bassett said. “The detection of poliovirus in wastewater samples in New York City is alarming, but not surprising. Already, the State Health Department – working with local and federal partners – is responding urgently, continuing case investigation and aggressively assessing spread. The best way to keep adults and children polio-free is through safe and effective immunization – New Yorkers’ greatest protection against the worst outcomes of polio, including permanent paralysis and even death.”