Did she eat Chinese?
During my months long trip to Asia, China was relatively clean, although I didn't go to the poorest areas (off limits). The far West where the Uiger Muslims are was fithly, as was Tibet. My understanding is the flus come from the South part of the country where it's historically poorer and typically more humid. As dirty as Tibet was, apparently it's too cold much of the year for viruses to get much of a foothold.
Nepal was a cleaner version of India, still had cows walking around, but it's also colder there, and smaller. Easier to contain. And I only went to the capital, I think the rest of the country is very poor and lacks sanitation.
India was the worst. Unbelievable really. Children in the middle of the street picking seeds out of cow shit to take home for dinner, everything in the country - every post, fence, building, telephone pole, everything - was yellow from the waist down.
Thailand was the cleanest. Very clean. The only place I'd eat the street food (although I did eat the street food in Xingjiang - that's all there was much of the time, and I stayed with uncut fruit and lamb shish-kabob cooked over the fire while I watched).