Scientists are closer to unraveling the mystery of a terrifying polio-like illness that spikes every two years among children. New research published Tuesday in the journal mBio says traces of antibodies found in the cerebrospinal fluid of affected patients add to growing evidence points to enterovirus, a common respiratory virus, is a cause of acute flaccid myelitis, which has paralyzed hundreds of youngsters in the last five years in the U.S. alone. The team also tested for antibodies of tick-borne diseases in the fluid and didn’t find any, indicating that’s not a factor. Federal health officials have been cataloging increases in AFM every two years since 2014. In 2018, there were 233 cases.