Heterophyiasis is infection with the intestinal fluke Heterophyes heterophyes, which is acquired by eating infected raw or undercooked fish from freshwater or brackish water.
Heterophyes heterophyes is endemic in the Far East, Middle East, and Egypt. Infection is acquired by eating infected raw or undercooked fish from freshwater or brackish water containing metacercariae (encysted stage). After ingestion, metacercariae excyst and attach to the mucosa of the small intestine. There, they develop into adults, growing to about 1.0 to 1.7 mm by 0.3 to 0.4 mm. Infection with Metagonimus yokogawai, a related trematode, has been reported after eating raw or undercooked freshwater or brackish fish in the Far East, Siberia, Manchuria, the Balkan states, Israel, and Spain. Intestinal infection with Nanophyetus salmincola has been reported after ingestion of raw or undercooked salmon.
Adult flukes can cause abdominal pain and diarrhea.
Diagnosis is by finding eggs in the feces.
Treatment is with praziquantel 25 mg/kg po tid for 1 day for H. heterophyes and M. yokogawai and 20 mg/kg po tid for 1 day for N. salmincola.
Last full review/revision July 2013 by Richard D. Pearson, MD
Content last modified October 2013