A "polio-like illness" that affects children is spreading across the United States and has now been found in 22 states, CNN reported Wednesday.
Acute flaccid myelitis, or AFM, mostly strikes children and affects the nervous system.
As of Tuesday, it had been found in 15 states. Today, that's 22, as the CDC tracks up to 127 potential cases. Sixty-two cases are confirmed.
On Wednesday morning, CNN brought Dr. Sanjay Gupta on to talk about the disease, which is still not well-understood.
Gupta said doctors know very little about the disease.
"We are not 100 percent sure yet," Gupta said. "Kids may have a cold-like symptom, cough, congestion and fever, and what is alarming and frightening is they suddenly develop weakness, and typically it's in an arm or leg, and you can look at the list of symptoms, and it comes out of the blue."
Other than muscle weakness without pain, there is not an obvious indicator that a child has been infected.
"At first they were not sure the symptoms were real because it came so suddenly, and that weakness comes and often times it persists and that's when the parents take their child to go see the doctor for the treatments available, but that's the pattern, sudden onset painless weakness," Gupta said. "These symptoms that are similar to cold-like symptoms, with this particular virus, what is probably happening is something is causing an inflammation within the spinal cord."
This disease is like a "hit-and-run," Gupta said, and "you don't have evidence of the virus but you do have evidence of the aftermath so it's hard to piece together."
The disease has left some children with paralyzed limbs. There is no known treatment other than physical therapy. It could be potentially deadly if the diaphragm is paralyzed because the child would be unable to breathe.
No one knows how the disease is spreading, Gupta said.
"It's a bit of a medical mystery," he said. "We don't know if it's something contagious."
Watch the CNN segment below.