The snails harbor a parasitic worm which they pass on to the water supply. The worms then use humans as a host and lay a large amount of eggs in the host. The w

The snails harbor a parasitic worm which they pass on to the water supply. The worms then use humans as a host and lay a large amount of eggs in the host. The worms and the eggs themselves cause an enormous strain on the hosts liver, kidneys, digestive, and urinary system. They essentially migrate through the body to get to the liver where they can lay thousands of eggs a day. Most eggs then enter the intestines in order to pass out of the host and back into the water supply to mature in snails and start the cycle over. The real danger is you don't need to drink the water, just come in contact with it. So stepping in a puddle could cause infection. I was just in Colombia and there was a campaign trying to raise awareness on this so I learned a bunch about it. Scary stuff!