I'm writing a fantasy book where the main group of humans live in a "swamp world." Picture Arrakis from Dune, but swap the desert for a swamp.
I don't want these people to have fire. I want them to be savage; their religion is focused upon the might of the tribe, and so they are brutal about the standards to survive. As such - they need to have enough energy to thrive and fight both each other and the environment.
As it stands, there is bacteria in the water that - should they survive infancy - makes their blood congeal faster and provide faster clotting. They eat animals from around as well as plant life.
However, I want to know some of the perils of this from an environmental stand point. How the human body would react to constant moisture, to frequently placed mud on the skin, and other things I'm not thinking of. Obviously there are predators, but what other person versus environment threats exist?