The U.S. Centers for Disease Control and Prevention is reporting a case of a mysterious, polio-like illness in Maryland.
The CDC said the Maryland case comprises one of 11 confirmed cases of acute flaccid myelitis in eight states.
The CDC said AFM is a rare but serious condition that affects the nervous system. It typically begins with a fever and stomach problems. Symptoms progress to mimic polio and can cause muscles and reflexes to weaken suddenly.
There are no known treatments or ways to prevent it.
"(It's) clearly a disease of children, no doubt about that," Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, told WBAL's sister station, WRC-TV. "So people -- CDC, (the National Institutes of Health), all the health people -- all scratching our heads saying what's clear is that we don't know what's causing this."
The illness tends to peak in the late summer and early fall.
Some children recover quickly, while others are left with a disability that could be permanent. If parents notice something's not right in their children, Fauci said not to wait to get help.
"Not only for the good of the child, but so that it can be made known that we have another case and perhaps finds some patterns. The CDC, the disease detectives that are always trying to find connections will get a better feel when the cases are reported immediately," Fauci said.
But he also said it's important to separate fact from fear.
"It's a one in a million incident. Although parents are understandably concerned about what they're hearing about now, we need to make sure parents are alert to it and aware of it, but don't get necessarily frightened to it because it really is a rare occurrence," Fauci said.
On Tuesday, the CDC warned doctors to be on the lookout for the illness.
In addition to Maryland, the confirmed cases were reported in California, Nebraska, North Carolina, Pennsylvania, Texas, Utah and West Virginia.