Among the concerns the CDC has are that the agency does not know the cause of AFM, why there has been an increase in cases since 2014, or the long-term effects of the illness.
Federal and state health officials are baffled by a mysterious and rare illness that seems to target children, causing paralysis.
The CDC says this is still a rare condition that affects less than one in 1 million people per year.
Doctors in Colorado experienced the same with children who fell ill in 2014, Dominguez said.
More than 90 percent of the cases are in children 18 years and younger.
Fox 2/KPLR 11's Dan Gray talked to an infectious disease specialist who said the disease isn't new but should be considered a growing health concern.
The most severe symptom of AFM is respiratory failure that can happen when the muscles involved with breathing become weak. IL health officials said they're working with the CDC to better classify the cases.
"I am frustrated that despite all our efforts we haven't been able to identify the cause of this mystery illness", Messonnier said. No pathogen has been consistently detected in the patients' spinal fluid. Six children in Minnesota were diagnosed with the disease since mid-September.
Although some AFM patients tested positive for an enterovirus, indicating a possible link, not all had the virus.
Messonnier stressed that while she understands how frightening this situation is for parents, they should remember that the infections are, in fact, rare. Unlike polio, there is no vaccine for AFM.
The number of confirmed cases reported to date is similar to levels reported in the fall of 2014 and 2016.
The CDC has provided information about AFM on its website and Messonnier encouraged parents to seek medical care immediately if they or their children experience sudden weakness of the arms or legs.
The two cases this year were in the southern and southeastern parts of the state. "So we're very lucky that he had (physical therapy) through early intervention".
"Nobody really knows treatment protocols, they don't know prognosis, and they can't really give parents an answer as to where this is coming from", she said. Some children paralyzed by AFM have eventually regained their ability to walk, but need time. So far, it's been reported in 22 states.