In an email Tuesday, Maryland Department of Health spokeswoman Brittany Fowler said the CDC will "make a determination about the status of the cases" in Maryland "based on clinical and laboratory information".
The condition remains very rare.
The MDH says the case is now being reviewed, and did not provide information regarding where in the state this particular case was diagnosed, or whether or not the child is in the hospital.
The disease affects the spinal cord and can cause weakness and pain in the arms and legs.
Although symptoms resemble polio, no evidence of poliovirus has been found in specimens from any case diagnosed so far, Messonnier said. The average age of those afflicted is 4, and 90 percent of those with AFM are 18 or younger. The highest number of cases took place in 2016, when 149 were reported cases in 39 states. The most severe symptom of AFM is respiratory failure, which can happen when the muscles needed to breathe become weak from the disease.
People can protect themselves from contracting AFM using methods similar to preventing getting the flu, Ellerin said.
The long-term effects are not known, and outcomes have been different for patients, with some recovering quickly and others having lasting paralysis and requiring ongoing care.
"As a parent myself I understand what it's like to be scared for your child", Messonnier said.
Officials began tracking the disease in 2014 when they received reports of 120 cases nationwide. Though AFM has not claimed any lives this year, there was one death in 2017. The CDC doesn't know what caused the spikes. "We recommend seeking medical care right away if you or your child develop sudden weakness of the arms and legs".
The agency knows that poliovirus is not the cause of these cases because the CDC has tested every single stool specimen from patients and none have tested positive for poliovirus. Messonnier said West Nile virus, which had been listed as a possible cause on CDC's website, is not causing the illnesses. "Parents need to know that AFM is rare even with the increase in cases we are seeing now".
The CDC is actively investigating and monitoring disease activity and recommends taking standard prevention measures such as hand-washing, protecting oneself from mosquito bites and staying up-to-date on vaccinations.
In a few cases, it appears that the illnesses were linked to viruses, including enterovirus.