From what you said ti sounds like a mojority of the illnesses are respritory which is bad but to us not near as bad as stomach illnesses. You can always subtly make reference to this school and see if anyone says "oh yeah my kid goes there" then kind of keep away lol. I know its immature but hey who wants a stomach bug? Not me, not you! Anyhow I'm sure you'll be OK, as was said keep clean hands.