More than half of all USA states have had confirmed or possible cases this year.
In Minnesota, four-year-old Orville Young was likely the earliest confirmed case in the state, according to the Star Tribune.
The surge has baffled health officials, who on Tuesday announced a change in the way the agency is counting cases.
"Be aware of the symptoms of any weakness in children", advised Dr. Vikram Prakash, a pediatric neurologist at Arnold Palmer Hospital for Children.
Since then, the agency has received information about 386 confirmed cases, mostly in children. "And the fact that it's hard to advise on prevention when the cause has not been identified". It dipped back down to 33 in 2017, before rising again in 2018.
Unfortunately, there is now no specific treatment plan for the disease, though medics may advise physical or occupational therapy on a case-by-case basis. The rare but serious disorder affects a person's nervous system, specifically the spinal cord.
Possible causes being considered include viruses that affect the digestive system called enteroviruses, and possibly strains of rhinoviruses, which cause the common cold, she said.
This year, the CDC believes cases of AFM are generally on track to match numbers from previous disease peaks; it's too premature to say that they know exactly how it will progress this year though, because they haven't had the same amount of time to study and diagnose the diseases in this year's patients compared with other years. Maryland's first case was reported September 21.
The disease may be caused by an enterovirus or rhinovirus, but these viruses have been found only in a few patients, which does not explain the increased number of cases at the end of summer.More news: Is Donald Trump undermining the Fed's independence?
'It's a one-in-million chance to get this so it's extremely unlikely your child will get this, ' said Dr Acosta.
King's Daughters pediatrician Dr. Aaron McGuffin says the condition is getting more attention because of the severity of the symptoms.
"We know this can be frightening for parents", Messonnier said in a news briefing.
Once diagnosed, some patients have recovered quickly, but some continue to have paralysis and require ongoing care, Messonnier said. The CDC emphasized that none of the children who developed these symptoms had the polio virus. However, Messonnier said in her report, the CDC has tested every stool specimen from AFM patients, and none have tested positive for poliovirus. Here's what puzzles health officials about AFM: The cause is still unknown.
History: The CDC has no idea why there has been a spike in cases, though there have been similar spikes in 2014 and 2016, according to Fox News.
Officials said they will be conducting additional analysis on this year's cases.
Staff at the hospital say she will be discharged on Wednesday and transferred to Shirley Ryan AbilityLab, a rehabilitation center where she will face several weeks of physical therapy to regain strength and movement. "And we can't always detect them in each individual patient for a variety of reasons". It causes the muscles and reflexes in the body to become weak or even paralyzed.
Adults can take preventative steps to protect children from illness as much as is possible - think: washing hands, using insect repellant, and staying up to date on vaccination programs.
How can people prevent AFM?
But some state health departments have been making public their reported cases.