Acanthoparyphium tyosenense: The discovery of human infection and identification of its source

Acanthoparyphium tyosenense Yamaguti, 1939 (Digenca: Echinostomatidae), was originally reported as an avian intestinal parasite. here, its presence is reported in 10 humans in the Republic of Korea. The patients were 9 adults aged 35-66 yr (males and females) and a young girl aged 7 yr residing in 2 coastal villages in Puan-gun, Chollabuk-do. The worms were recovered after treatment with praziquantel and purgation with magnesium salts. A total of 158 specimens (1-107 specimens/ individual) was collected, together with v arying numbers of other intestinal flukes. The patients had eaten various k inds of brackish water mollusks caught in an estuary near their villages. F ive bivalves and a gastropod species suspected as sources of human infectio n were collected and examined. Two bivalves (Mactra veneriformis and Solen grandis) and the gastropod (Neverita bicolor) were found to be infected wit h the metacercariae of A. tyosenense; adult flukes were confirmed after the experimental infection of chicks. The results show that A. tyosenense infe cts humans and that brackish water mollusks are the source of human infecti on.