While the CDC has yet to confirm a case in Virginia, Hoff said her son Camdyn was diagnosed with AFM while hospitalized at UVA Medical Center, falling ill with the telltale symptoms.
The CDC's Messonnier said, "We know this can be frightening for parents".
"I am frustrated that despite all our efforts we haven't been able to identify the cause of this mystery illness", Messonnier said.
Each year since then, usually in August or September, the CDC has logged a spike in the illness.
This year's numbers are similar to 2016 and 2014.
It's too early to know whether the total for 2018 will surpass those previous years.
Messonnier said the CDC has definitively ruled out polio - which causes a similar set of symptoms - as the cause.
It attacks the nervous system, specifically the spinal area.
The CDC says AFM's cause can vary from a virus to environmental toxins to genetic disorders.
Officials with the Iowa Department of Public Health said they are following the condition very closely and heeding warnings from the Centers for Disease Control and Prevention. This is the first report of potential AFM to the NDDoH.
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However, the 2018 edition, using the new criteria, "backcast" data for 2017 and came up with new rankings for that year. The highest mark possible is 100 points, an imaginary ideal "frontier" of economic competitiveness.
The agency has not yet confirmed whether the New Hampshire patient, a juvenile from Rockingham County, contracted AFM or if it is another illness, said Jake Leon, a spokesman for the state Department of Health and Human Services.
"There is a lot we don't know about AFM", Messonnier told NPR in a teleconference with reporters on Tuesday.
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'". But she stressed that despite the increase in cases, the illness is still very rare, occurring in fewer than 1 in a million people in the US each year.
Symptoms of AFM include sudden limb weakness, loss of muscle tone and reflexes, facial and eyelid drooping, difficulty moving the eyes, difficulty swallowing and slurred speech, the CDC said.
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. We have not confirmed the cause for the majority of these cases.
The illness can lead to serious complications - including paralysis or respiratory failure - and requires immediate medical attention.
"The data on the recently reported cluster of cases of AFM will have to be carefully evaluated to better understand the role of EV-D68 in this new outbreak". Most of the cases are in children under the age of 19, with kids under the age of 4 appearing to make up the biggest portion of cases. However, experts say that initial indications from a small number of cases suggest a grim outlook. Doctors may also recommend physical or occupational therapy to help with arm or leg weakness.
Messonnier said the CDC has tested every stool specimen from AFM patients.
The CDC says disease prevention steps should be followed, including staying up to date on vaccines, washing hands and using mosquito repellant.
Benjamin Greenberg, a neurologist who has treated children with AFM at the University of Texas Southwestern in Dallas, said AFM is "exquisitely rare".