I was thinking Norovirus, too. Here in NC, there is now an annual "tradition" of a Norovirus outbreak along the Appalachian Trail in late April/early May, where the "bubble" of each season's thru-hikers who started in Georgia crowd shoulder to shoulder in the shelters along the first couple or three hundred miles of the trail. Sanitation is at a low ebb, hikers are physically stressed, one person picks up the virus, and the next thing you know is dozens of hikers along dozens of miles of the AT are laid low by rapid onset double-ended "fluid loss". It sounds as though your superior physical condition limited the duration of the symptoms at least somewhat, though surely it couldn't have seemed brief to you two.
I normally read your trip reports while thinking "Man, I'd like to do that trip". Your Thanksgiving trip--not so much. Thanks for the wonders of Wonder and looking forward to more!
Foy