Human botfly larvae ... and hatch waiting for the next bare foot to pass by. But some egg-laying parasites go more than just skin deep. Tapeworms, for example, invade your intestines.

When those animals go to their bathroom, sometimes, their feces contains hookworm eggs ... but the worms can enter through any part of the skin. It cannot spread between humans.

It's a good idea to trim fingernails too, to prevent the eggs from getting caught under them. Threadworms aren't the only worms (helminths) that invade humans ... through the skin and travel ...

A Toronto doctor is alerting Canadian tourists about the re-emergence of skin-eating screwworms, which had been contained in South America.