Human fascioliasis in Corozal, Puerto Rico.

A limited survey for human infection with F. hepatica was conducted in the mountain region of Corozal, Puerto Rico. This region was selected because bovine fascioliasis was hyperendemic, watercress was grown locally for human consumption, and Lymnaea cubensis snails (an intermediate host for F. hepatica in Puerto Rico) were found in the watercress farms. Of 110 fecal samples examined 12 were positive for F. hepatica. Seven matched serum samples were also positive for F. hepatica antibodies by counterelectrophoresis. Eleven of the 12 infected individuals had a history of eating watercress. This is the first survey to demonstrate a relatively large proportion of asymptomatic. F. hepatica-infected humans in Puerto Rico. Other helminth parasites commonly found in the study population included Trichuris trichiura and hookworm.