Health officials: 5 possible cases of rare polio-like illness under investigation in Maryland

Five Maryland children may have contracted a rare virus with symptoms similar to polio, according to state health officials.

The Centers for Disease Control and Prevention (CDC) has confirmed cases in 22 states overall. Making matters even more concerning, investigators are not sure what is causing the outbreak.

The illness is called acute flaccid myelitis or AFM. It is a rare, but serious condition - fewer than one in a million Americans will get AFM every year, the CDC estimates.

Symptoms include the sudden onset of arm or leg weakness and the loss of muscle tone and reflexes. Some patients will also experience facial weakness, difficulty moving the eyes, drooping eyelids or slurred speech.

More than 120 confirmed or possible cases are under investigation nationwide, according to the CDC.

"It attacked [my child's] body and her spinal cord a certain way that seems to be happening to other kids too," said Josh Payne, the parent of a child battling AFM.

There are no known cases of the illness in either Virginia or D.C., according to area health officials. CDC officials added that while they have not seen any geographical clustering, they have seen seasonal clustering, with most cases occurring in the late summer and fall, dating back to when the CDC first noticed an uptick in the illness in 2014.

"Despite a lot of investigation by CDC and our partners, AFM remains a mystery disease," said Dr. Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases for the CDC.

Officials said some people diagnosed with the illness recover quickly while others need ongoing care.