I had a bit of a finicky tummy all my life, but it was a virus about 12 years ago that took me down for over a week - couldn't keep a thing in - that made it impossible for me to handle any gluten at all. I lost 5 pounds I didn't have to lose & needed IV fluids and a shot to stop my stomach from spasming at the end of that week. It was horrible. It took me a year to figure out gluten was an issue - lots of ups & down with stomach 'illness' and denial.
Did the virus cause it ?
Most info on celiac says it can be triggered by a stressor - pregnancy, life stress, a virus, etc. That's not saying the virus caused it, rather the extreme stress the body is under due to the virus turns on some gene that is celiac disease.
How about another example - someone's parent dies - extreme stress - they develop celiac disease. Turn that around and say that a parent dying causes celiac disease. Not exactly ! One would have to have the celiac gene AND conditions would be just right to turn it on.