It happened between a farm off each coast and there was NO physical traffic of any kind between the two farms, and there was no shared resources either. floating on air currents between the two farms was really the only explanation they could come up with that was at ALL feasible. Everything else pretty much is just "MAGIC! It was magic."

It seems just utterly ridiculous, but when you know more about the disease...it's almost not. FMD is one of the biggest reasons that they check your shoes at customs. Even the tiniest bit of infected manure in the smallest bit of soil on your shoes can be infectious. It's just INSANELY contagious.