Human nanophyetiasis: transmission by handling naturally infected coho salmon (Oncorhynchus kisutch)

Abstract

The first US case of human nanophyetiasis that does not involve ingestion of raw or undercooked salmonid fishes is reported. The patient worked with highly infected fish. Hand contamination with the infectious metacercariae of the digenetic trematode Nanophyetus salmincola (family Troglotrematidae) occurred during the handling of fresh-killed, juvenile coho salmon, Oncorhynchus kisutch. Diagnosis of nanophyetiasis was based on the clinical findings of chronic diarrhea, nausea, abdominal discomfort, and a peripheral blood eosinophilia of 43% and was confirmed on finding characteristic bipolar eggs in a stool specimen. The patient rarely ate seafood products and never ate raw or cold smoked fish. He responded favorably to praziquantel and was asymptomatic after therapy.