Really glad to hear that he is responding well to iritis treatment Ann and that he is mostly back to normal.
I hope they will be able to culture for the culprit, salmonella or the like may very well have caused a ReA and the GI illness would definitely be the kind of physical stressor that could've triggered the immune response into an iritis attack. I always worry about any form of food poisoning, as food is a gamble that we can't be certain of avoiding 100% of the time. No-one should have to deal with this rotten stuff at 10 yrs old, the poor little guy. My very best wishes that he can be treated effectively to avoid more lasting troubles.
Hugs for better days ahead!
mig