One of the two other studies published alongside Bove’s sought to narrow the definition of the disease so that it could be distinguished from other neurologic diseases that have overlapping symptoms, such as spinal cord stroke, Guillain-Barre syndrome, and meningitis.

“Our main goal was to prepare ourselves for future research studies that are going to be needed to get an understanding of the causes, diagnoses and treatment,” said the study’s lead author Dr. Matthew Elrick, a fellow in neuromuscular medicine and pediatric neurology at the Johns Hopkins School of Medicine.

The description used by the CDC is good enough as a screening tool, Elrick explained, but to really unravel the details of the disease, you need a much more restrictive set of diagnostic criteria to make sure you are only looking at cases of AFM. One of the signs that distinguishes AFM from other paralyzing diseases is that it doesn’t cause a loss of sensation in affected limbs, Elrick said. AFM also appears to affect limbs on one side of the body more severely than the other. So if both arms are affected, the right (or the left) might be worse.

What is known so far is that AFM’s symptoms “are almost identical to those of polio,” Elrick said. “In fact it’s almost indistinguishable from polio, except for some subtle differences.”

The disease is thought to be caused by viruses from the same family—the enteroviruses—as the polio virus. But in many children the virus hasn’t been isolated, so the connection isn’t solid yet. Elrick and others believe the reason the virus isn’t being found in some children is that the initial symptoms seem so benign—very much like the garden variety cold – that kids aren’t brought right away to a doctor. By the time paralysis sets in, the thinking is, the virus has burrowed deep within the cells in the spinal cord and doesn’t show up in tests.

“Based on animal models – and the experience with polio—we know that the virus can live inside cell bodies,” Elrick said. “The only way it could be confirmed during the polio era was through autopsy.”

What scientists know from polio is that certain viruses can kill nerve cells, Elrick said. When kids go through rehab and recover function it’s not because new nerve cells have been made, but because the surviving ones have stepped in and taken over the jobs that the dead ones used to do.