Only one case has been confirmed this year, but officials are still investigating the latest possible cases.
Since mid-September, six children under the age of 10 were hospitalized and diagnosed with AFM in Minnesota.
A study of children diagnosed with AFM in Colorado in 2014 found that majority were better one year later, although most also had residual weakness in their arms and legs.
The agency said it hasn't confirmed the cause for the majority of the cases, which primarily occur in children.
The CDC says symptoms of AFM include facial drooping or weakness, difficulty moving the eyes, drooping eyelids or difficulty swallowing or slurred speech.
Parents usually notice the child's loss of the use of an arm or a leg.
He had just recovered from a cold and fever in July.
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"The results come back that he had an abnormality throughout his entire spinal cord", Elaine Young said. "He was weak, he couldn't walk".
Orville was diagnosed with AFM and spent six days in the hospital.
Between August 2014 and August 2018, the CDC received 362 cases of acute flaccid myelitis (AFM).
"The cause of any individual case of AFM can be hard to determine, and often, no cause is found", the Washington State Department of Health said in a release on Wednesday.
Dr. Elizabeth Meade, chief of pediatrics at Swedish Pediatrics, says AFM is more common in kids and is sometimes associated with viruses. A 2014 uptick in the number of cases coincided with the outbreak of a respiratory illness caused by eneterovirus D68.
The children are from King, Pierce, Snohomish and Lewis counties, the health department said. "So at that point, where it burst onto the scene, the CDC took initiatives to make this condition reportable".
During 2015, CDC did not receive information about large EV-D68 outbreaks in the United States, and laboratories reported only limited EV-D68 detections to CDC's National Enterovirus Surveillance System (NESS).
"There is obviously a lot of concern about it, but it is rare", Griffith said. 20, prompting the Minnesota Department of Health to ask doctors to be on the lookout for the disorder, which has severe consequences but mysterious origins.
The U.S. Senators from Iowa and Minnesota are asking for an investigation into a rare polio-like illness that has infected seven children across both states.
"From what my understanding is, if there is an external causal agent, it may be hard to determine when the exposure to that agent occurs", Kenyon said. "Cases have been reported from the Twin Cities, central Minnesota and northeastern Minnesota", the state health department said in a statement.
AFM is not known to be contagious, she said.
There is no specific treatment for AFM, but a doctor who specializes in treating brain and spinal cord illnesses (neurologist) may recommend certain interventions on a case-by-case basis.
Health officials in Minnesota and at the CDC have recommended general preventive steps. Among the viruses that can cause AFM are West Nile virus and poliovirus. This condition is not new, but the increase in cases we saw starting in 2014 is new.