Haplorchis taichui, H. pumilio, and Other Haplorchis Species

Human infections with Haplorchis species (Haplorchis taichui, H. pumilio, H. yokogawai, and H. vanissimus) occur in areas where freshwater or brackish water fish is consumed raw or under improperly cooked conditions. H. taichui is distributed mainly in Asia but was also reported in the Middle East (including Egypt) and Pacific Islands (Hawaii). H. pumilio has an almost worldwide distribution from Africa to the Middle East, Asia, Australia, and North and South Americas. The geographical distribution of H. yokogawai is similar to that of H. pumilio but has never been reported from North and South America (except Hawaii). Freshwater or brackish water snails serve as the first intermediate host, and a wide variety of fish species, including carps, minnows, mullets, and Tilapia, take the role of the second intermediate host. Adult flukes parasitize the small intestine of humans and animals (birds and mammals) and can cause diarrhea, abdominal pain, and weight loss. The diagnosis is based on the recovery of eggs in feces, but serological and molecular techniques are also available. The drug of choice for Haplorchis spp. infection is praziquantel.