A few days ago there was discussion re Bali Belly. In Canada we have a vacine called Dukaral (sp). It is supposed to inooculate one for E-Coli infection. You take it in two doses taken one week apart. I used it last time I was in Bali and it may have worked for e-coli but I came back with Giardia so if one dosen't get you the other will.