The Centers for Disease Control and Prevention has been investigating hundreds of cases of acute flaccid myelitis dating back to 2014. It affects the nervous system, specifically the area of spinal cord called gray matter, which causes the muscles and reflexes in the body to become weak. This condition is not new, but the increase in cases starting in 2014 is new. Still, CDC estimates that less than one in a million people in the United States will get AFM every year.

In recent months states have been reporting more cases. Twenty-two states have confirmed cases this year. Currently, 127 patients are under investigation. Sixty-two cases have been confirmed. One child died in 2017.

The disorder, which mainly affects children, can paralyze a person's arms and legs. Some children recover and others remain paralyzed. The average age of those afflicted is 4 years old, and 90 percent of those with AFM are 18 or younger, the CDC said.

Nancy Messonnier , Director of the National Center for Immunization and respiratory Diseases at CDC says."we haven't been able to identity the cause of this mystery illness."

Symptoms are similar to a severe respiratory illness along with a fever, but those progress into neurological symptoms. Some people with AFM will feel weakness in their arms or legs, a loss of muscle tone or slower reflexes. The most severe symptom is respiratory failure. If you or your child develops any of these symptoms, you should seek medical care right away.

There is no specific treatment for AFM, but a doctor who specializes in treating brain and spinal cord illnesses (neurologist) may recommend certain interventions on a case-by-case basis.