Schistosomes are parasitic flatworms that have a snail intermediate host and a human definitive host.
After developing in the snail, they (cercariae stage) escape into the water and can attach to the skin of a human. Then, it will penetrate the skin and migrate into areas of the human's body.
I have been unable to find any information on the mechanisms related to attachment to the human host's skin. More specifically, my questions are:
- Do they attach to whatever they can find, and can only develop into the next stage if they (by chance) attach to the right host?
- If they selectively attach to human host skin, how do they detect the skin? What makes the skin distinguishable to them?
Here is a great picture of the life cycle of these parasites, for reference.