Heterobilharzia americana (HA) is a parasitic blood fluke that infects various species of mammals, including racoons, dogs, cats, and humans. It is a trematode parasite endemic to the Gulf Coast regions of the United States which also has been reported in Kansas, North Carolina, and Indiana. The parasite's life cycle involves snails as intermediate hosts, where they release cercariae that penetrate the skin of their mammalian hosts, causing a dermatitis-like condition. Dogs are exposed to infection when immersed in freshwater lakes or streams harboring lymnaeid snails (the intermediate host). The cercariae then migrate to the lungs and liver, where they mature into adult flukes and lay eggs. Heterobilharzia americana cercariae from snails have been incriminated in causing dermatitis in humans (“swimmer’s itch”) following skin penetration.