From the point of view of its ultimate (human) host, the parasitic flatworm Schistosoma mansoni has a gruesome way of life. It hatches in feces-tainted water, grows into a larva in the body of a snail and then burrows through human skin to take up residence in the veins. Once there, it grows into an adult, mates and, if it’s female, starts laying eggs. It can remain in the body for decades.
