An adult male in Wisconsin has been diagnosed with AFM:
The average age of the patients in all confirmed cases over the past five years is just 4 years old, and more than 90% of the cases overall occur in children 18 and younger, according to analysis of cases reported in recent years.
You can read the rest @
One thing I have NOT seen is whether anyone OUTSIDE of the US has this disease. If not, that would tell us something about potential causes.
By the way, do you think it strange that neither the linked report nor the video states his age? I do.