AFM virus symptoms to watch for as the seasonal illness appears ready to return

No diagnostic laboratory test exists for acute flaccid myelitis (AFM). Kids usually show typical virus symptoms before AFM sets in.

Acute flaccid myelitis (AFM) made local headlines last year as Norton Children’s Hospital treated three children for the polio-like disease. The rare and mysterious illness typically pops up in late summer and early fall, but more than a dozen cases have already been reported nationwide this year.

According to the U.S. Centers for Disease Control and Prevention (CDC), AFM causes weakness in the arms or legs. It affects the person’s nervous system, specifically the spinal cord. The cause isn’t known, but one possibility is an immune reaction to an infection called enterovirus, which can be spread by coughing or sneezing.

“Recognizing AFM is challenging because there’s no diagnostic laboratory test for it,” said Michael L. Sweeney, M.D., pediatric neurologist with Norton Children’s Hospital and UofL Physicians – Child Neurology. “In most cases, AFM patients are healthy children who experience symptoms consistent with a viral infection. They then develop AFM.”

The CDC began tracking AFM in 2014. Last year was the largest outbreak since that time, with 233 cases in 41 states. So far this year, 11 confirmed cases have been reported in eight states, and dozens of others are under investigation.

While the paralysis and the late-summer occurrence are reminiscent of polio, the CDC said all of the patients it tested were negative for poliovirus.

Ninety percent of AFM cases have been in children.

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AFM virus symptoms

The CDC said there are symptoms that could signal the onset of AFM: symptoms of a flu-like infection followed by sudden arm or leg weakness and loss of muscle tone and reflexes. Other symptoms include:


  • Facial drooping or weakness
  • Difficulty moving eyes and drooping eyelids
  • Slurred speech or difficulty swallowing
  • Pain in arms and legs


“If parents notice these symptoms, it’s important they take their child to the doctor quickly,” Dr. Sweeney said.


“Cough and sneeze into your elbow or at least covering your mouth, and thorough handwashing,” said April R. Mattingly, M.D., pediatrician with Norton Children’s Medical Group – Crestwood. “And keep your children home when they’re sick.”

April R. Mattingly, M.D.

Preventing AFM

While there is currently no vaccine — or cure — for AFM, doctors recommend practicing the same methods used to prevent other illnesses.