As a rare but paralyzing illness continues spreading across the U.S., affecting the lives of parents and children in 27 states, federal health officials are struggling to pinpoint its cause, USA Today reported on Tuesday.
> The Centers for Disease Control and Prevention on Tuesday raised the number of cases of acute flaccid myelitis reported this year to 90, spread among 27 states. An additional 162 patients are under investigation.
> The disease is rare: It afflicts fewer than one in a million children. But symptoms are life-altering. It can paralyze a child's arms and legs. Some need ventilators to breathe. It can also cause muscle weakness, slurred speech and difficulty moving eyes and swallowing.
The primary suspect has been a strain of a respiratory virus called enterovirus, most common in late summer and early fall, but federal health officials say there is not enough evidence to definitively label this particular virus as the cause AFM.
> Nancy Messonnier, the CDC's director of the National Center for Immunization and Respiratory Diseases, said patients with AFM typically had a fever or respiratory illness three to 10 days before they developed weakness in the arms or legs.
Messonnier said it is possible that enterovirus is the cause, but it is also possible that the virus triggers an immune system response, which in turn results in the disease.
She noted that although respiratory viruses are common this time of year, only a small fraction of children go on to develop AFM.
> "What we don’t know is what's triggering AFM," Messonnier said. "It may be one of the viruses we have already tested. It may be a virus we haven’t yet detected. Or it could be the virus is kicking off another process and it is actually triggering (AFM) through an autoimmune process."
> Although there have been no reported deaths in 2018, Messonnier acknowledged that the CDC has not continued to track patients diagnosed in past years. The agency has asked state health departments to match confirmed AFM cases against death registries since 2014 to check whether any kids or adults have died.