How do blood fluke larvae enter the human body?

Blood fluke larvae, known as cercariae, enter the human body primarily by penetrating the skin upon contact with infested water. When these fork-tailed larvae emerge from their intermediate snail host into the water, they attach to the skin of a human, shed their tails, and burrow into the tissues to reach the blood circulation.1

In the case of the urinary blood fluke (Schistosoma haematobium), the mature larvae may also enter the human host through the mouth. Infection is commonly contracted by individuals who work, bathe, or swim in water populated by snails that carry these parasitic flatworms.21