It is a really weird trip and you have to bring antibiotics in case you get parasites. Don’t drink the water. Brush your teeth with bottled water and keep your mouth shut in the shower. We in America don’t understand how clean our environment is on a world continuum.
Sometimes it’s simply a matter of different ‘bugs’ in another place (that you go to) that you haven’t been raised with, in your own home region. It can happen the other way around, too.