Extremely. According to the CDC, there were 38 confirmed cases in 16 states this year through September 30. Specifically, the disease affects the area of the spinal cord called gray matter. But federal officials said that those viruses have not been linked to the US outbreak over the past four years.
Kristen Ehresmann, director of Infectious Disease Epidemiology, Prevention, and Control at the Minnesota Department of Health, told Healthline, "it's very concerning".
Andrea Kunicky, spokesperson for UPMC Children's, declined to comment on any cases at the hospital. "We recommend seeking medical care right away if you or your child develop sudden weakness of the arms or legs". The most severe symptom of AFM is respiratory failure, which can happen when the muscles needed to breathe become weak from the disease. The CDC has yet to figure out a common link between all the cases that have been reported, although they did note that several of them seem to have been linked to infections by other viruses, enterovirus D68.
While the cause of AFM is not clear, experts say it can occur as a result of a variety of viral illnesses including the polio virus, enteroviruses, West Nile virus, and adenoviruses. "In this cases it's unknown", Ehresmann said.
The number of confirmed cases has been on the rise since late 2014, when there were 120 confirmed cases from August to December in 34 states.
"What we have been told is that he's the best case scenario of a hard situation", she said. More than 90 percent of the confirmed cases have been in children 18 and younger, with the average age being 4 years old. Then in 2016, it peaked again with 149 cases in 39 states.
For example, the CDC doesn't know who may be at higher risk for developing AFM or why some are at higher risk, she said. She noted the confirmed cases are in 22 states.
They also know that all six children developed the disease around the same time.
"The cases are from all over the state", Ehresmann said.
There's no way to determine which child will development AFM, according to Glatter.
The U.S. Centers for Disease Control is warning about a rare mysterious illness affecting American children, which can cause "polio-like" symptoms. "The search for a biomarker from the blood or cerebrospinal fluid would be helpful to identify those at elevated risk".
As of yet, there is no known effective treatment for the condition, but the vast majority of patients do recover with treatment.
Once diagnosed, some patients have recovered quickly, but some continue to have paralysis and require ongoing care, Messonnier said.
New Jersey has three confirmed, and three more are suspected.
"It's rare, but certainly when you hear about it it's very scary for parents", CBS News medical contributor Dr. Tara Narula told "CBS This Morning". The CDC estimatesfewer than 1 in a million Americans will get the disease.
"As a parent myself I understand what it's like to be scared for your child", Messonnier said.
Ehresmann noted that the sudden onset of muscle weakness is the most obvious sign.
Danielle Finkle, a mother from IL who was interviewed, said about her son: "He came to me and he's supporting his left arm with his right arm, and he says, 'Mommy my arm's broke'". Parents who want to protect their children should encourage the same sort of good hygiene that protects kids against cold and flu, such as washing their hands frequently and covering coughs or sneezes, Dominguez said.