The Centers for Disease Control and Prevention says it's now investigating 127 cases of AFM, or acute flaccid myelitis, in 22 states.
Sixty-two cases have been officially confirmed. The disease is still very rare and affects less than one in a million American children.
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However, that doesn't mean there isn't a lot of concern.
The stories are similar: a child is sick, then within days sudden weakness sets in, with many unable to move their arms and legs.
During a briefing, CDC doctors said they're frustrated that lab tests haven't zeroed in on a specific cause for this year's cases of AFM.
They have ruled out polio and are now looking at a range of potential culprits.
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"AFM can be caused by other viruses, such as enterovirus and West Nile virus, environmental toxins, and a condition where the body's immune system attacks and destroys body tissue that it mistakes for foreign material," said Dr. Nancy Messonnier, the director of the National Center for Immunizations and Respiratory Diseases.
Ninety percent of the AFM cases in 2018 are in kids 18 years or younger. The average is 4 years old.
Geographically, cases are spread out across the country.
Although AFM is reported in other countries, none has the pattern seen in the U.S., with a spike in cases every two years seen in late summer to early fall.
The CDC says this year's numbers are similar to those in 2014 and 2016, but investigators aren't any closer to knowing which children are at higher risk of AFM or why.
Another mystery remains, and that is the long-term prognosis for those sickened.
"We know that some patients diagnosed with AFM recover quickly, and some continue to have paralysis and require ongoing care," says Dr. Messonnier.
The CDC says until more answers are known, parents should take these precautions:
- Everyone in the family should wash their hands frequently
- Make sure everyone has their vaccinations up to date
- Use insect repellent to prevent mosquito bites
For more information on AFM, visit www.CDC.gov.
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