I need to visit Nepal every 2 years (at least). I was there 2 years ago and got very sick in the second week, basically stomach flu, probably salmonella or e.coli or both.
I was there about a month ago and became sick again in a similar fashion, although it seemed very slightly less dramatic, no high fever this time etc.
Can I expect to gain immunity against e.coli at least or maybe even salmonella? Can I expect to get a stronger stomach, which is not so easily upset? Do frequent travelers to Asia or Africa, who tend to experience these type of problems tend to experience them less the more they travel?
I have asked a similar question on The Great Outdoors and was advised to ask on Health as well.