"This is a mystery and we haven't solved it yet, so we have to be thinking broadly", said Messonnier, adding, "You'd think that we would finding a single agent and that's not what we're finding".
Boston Children's Hospital has evaluated all of the confirmed and suspected AFM cases that occurred in MA this year. "A respiratory illness or a viral illness and then it's the development of a sudden weakness", said Berbari.
Early symptoms mirror those of a common cold such as cough, congestion, and fever.
A Tennessee mother says her son is the latest victim of a mysterious polio-like disease that is concerning parents across the country.
"3-year-old Aamira is truly one in a million", the hospital wrote on Facebook.
A main symptom of AFM is the onset of sudden muscle weakness in the arms and legs. In 2017, one person died of AFM.
In September, Pardo-Villamizar and his colleagues published a follow-up of 16 patients stricken in 2016 that concluded that "the majority of children with AFM have limited motor recovery and continued disability".
Messonnier did not address enterovirus D68 directly during the news conference and said the CDC has not yet had time to fully analyze the cases from this summer and fall.
None of the specimens has tested positive for polio virus, however.
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Some children with AFM recover full motion and strength-usually within a few months-whereas in others the nerve damage seems permanent, she says. "In this cases it's unknown", Ehresmann said.
"It's not really highly exciting stuff", she said, "but it's a good reminder of things you can do on a daily basis". But treatments for the infection itself remain elusive. Nationwide, the Centers for Disease Control and Prevention has reported 62 cases this year and a total of 386 since 2014. AFM may be one of them.
Messonnier said some patients diagnosed with AFM have recovered quickly while others continue to struggle with paralysis. It's the first such case at the hospital.
"Treatment options are quite limited", he said. Polio was eradicated in the U.S.by vaccination.
So far, viruses, environmental toxins and genetic disorders are all possible causes for the spike. Similar waves of the same illness occurred in 2014 and 2016.
Why is AFM likened to polio?
Victims generally suffer from muscle weakness and some paralysis of the face, neck, back, arms and legs. It's unclear from mouse studies whether AFM symptoms will return in afflicted individuals, Tyler says.
AFM cases tend to start in August, peak in October and taper off by December, according to the CDC. Doctors at Children's have not seen an AFM patient needing a ventilator this year, but have treated such cases in the past, Benson said.
No cases of polio have originated in the U.S. since 1979, while in Australia, the last case of the disease caused by a locally acquired virus was in 1972.
Kerkering said doctors aren't sure what causes the spinal infection.