NEW YORK (CBSNewYork) – A mystery illness that attacks the nervous system, paralyzing some children, has many parents concerned across the country.

Cases have been reported in 22 states, with possibly one case in California.

Health officials urge parents to be vigilant, as there’s a lot unknown about the syndrome and what causes it.

More: CDC: Cases Of Paralyzing ‘Acute Flaccid Myelitis’ Reported In 22 States

For little Maipele Burns, it began with a serious asthma attack, and then she lost function in her right arm.

“My husband that noticed her arm was kind of just hanging there,” her mother, Carlene, said.

For 3-year-old Camden Stravers, what his parents thought was the common cold developed into something far worse.

“He stopped being able to support his head, his right arm function went away, and he couldn’t stand up,” said his father, Justin.

More: ‘Acute Flaccid Myelitis’ Causing Polio-Like Symptoms In Midwest Children

Health experts say acute flaccid myelitis, or AFM, is a polio-like syndrome that affects the nervous system, specifically the spinal cord. Muscles and reflexes are weakened, and some patients are left paralyzed.

More than 90 percent of the cases are in children 18 years and younger.

“What parents have to know is if your child suddenly has a weak arm or leg, is not speaking properly, has a stiff neck or a wobbly neck – call the doctor immediately,” pediatrician Dr. Laura Popper said.

Doctors say the most serious cases can lead to respiratory failure.

The Centers for Disease Control and Prevention report 62 cases in 22 states this year. Another 127 cases are suspected.

“This is truly a mystery disease. We actually don’t know what’s causing this increase,” said Dr. Nancy Messonnier, of the CDC.

AFM is still extremely rare. CDC experts say the overall rate of AFM is about one in a one million.

The CDC says to be on the lookout for the onset of arm or leg weakness, and loss of muscle tone and reflexes. In addition, some people will experience the following:

  • facial droop/weakness,
  • difficulty moving the eyes,
  • drooping eyelids, or
  • difficulty with swallowing or slurred speech.

For more information on AFM, CLICK HERE.