S.J.
Hi D.,
I have no experience with this virus, but to add to what Amanda said, you can also get probiotics (like acidophilus) in chewables or in granules that can be added to kids food. The granules are behind the counter at the pharmacy because they have to be refrigerated, but you don't need a prescription. The chewables (there's one with a big picture of a strawberry on the front that my kids LOVE) you can sometimes get at GNC (don't get their own brand -- they're gritty) or at Home Economist (South Blvd near southend or Independence Blvd...I don't know if there are any other locations). These are the good bacteria that you system needs.
Good luck!!