Praziquantel for treatment of human Nanophyetus salmincola (Troglotrema salmincola) infection.

Human nanophyetiasis is a zoonotic disease recently recognized in the coastal US Pacific Northwest and is caused by the digenetic trematode Nanophyetus salmincola. Ten additional stool-proven cases from the same geographic area have been identified; five presented with histories of gastrointestinal complaints and five had eosinophilia. Nine of 10 patients had histories of fish ingestion (incompletely cooked or home-smoked salmon or steelhead trout) and were treated with praziquantel. Several individuals noted prompt resolution of symptoms following therapy. In all treated cases subsequent stool examinations were negative for eggs of Nanophyetus. Nanophyetiasis may be the most commonly encountered trematodiasis endemic to North America, and the use of praziquantel in its treatment appears to be efficacious.