How do tribes get clean water? how do tribes protect themselves from snake/insect bites+diseases?

Why in the world is this question in Infectious Diseases?? "how do rainforest tribes get clean water?" -- From whatever part of the Amazon river or tributary they live near. It may or may not be clean. Clean is relative. The indigenous tribes harbor intestinal parasites. How could they not? "and how do they protect themselves from bites and diseases?" -- Insect bites? Animal bites? Their best protection against bites is an intimate knowledge of and deep respect for their environment and its other inhabitants. Their best protection against many diseases is an isolation from so-called civilized man.

Mine's a bit of a silly theory and it's probably not correct, but I think it has to do with pheromones or a certain smell. I'm British (English) and here there's absolutely no poisonous animals at all (except adder snakes, I think) but last year I went to visit my friend in Kansas in the US, where they have tons of poisonous and dangerous animals, bugs etc. Well we went into this forest to test out a new gun he'd bought FROM WALMART (Americans..... lol) and, bare in mind it was bloody hot, middle of july, the place was rife with ticks and other nasties.... Well when we were there I found I had 3 ticks on my body by the time we left and had hornets buzzing around me the whole time, but my friend who had lived there for about 6 years at the time was walking around without a shirt on and nothing happened to him!!! So I think bugs and things can tell when it's a new person with a different scent to the people who are from there, they think YUM, FRESH MEAT!!! Lol. So in my theory, the tribes people will have pheromones that the insects will be used to and not react overly excitedly to, but when someone new comes into the environment they go nuts! That's just what I think anyway lol