Kevin Messacar and colleagues at Children’s Hospital Colorado found themselves remarking on how reminiscent the unfolding investigation was of a medical mystery they’ve been enmeshed in for the past eight years — acute flaccid myelitis, or AFM, a polio-like condition in children.

Meanwhile, Carlos Pardo, the co-principal investigator of a National Institutes of Health study into the natural history of AFM, started fielding queries from hepatologists at Johns Hopkins Medicine, where he teaches, about what kinds of samples they should be collecting from suspected hepatitis cases.

“There are many parallels between this initial investigation of these cases of hepatitis of unknown origin and our initial investigations of AFM cases,” Messacar, a pediatric infectious disease physician and an associate professor at the University of Colorado, told STAT.