Background: Fish-borne trematode infection is a parasitic zoonosis with a great variety of clinical manifestations. According to current information, the metacercaria of heterophyid trematode can be found in freshwater fish, especially the cyprinoid group.
Objective: To investigate the prevalence of Heterophyidae metacercariae in freshwater fish.
Material and methods: A parasitological investigation was done using 129 fish from 17 species: Labiobarbus siamensis, Puntioplites proctozysron Barbodes gonionotus, Barbodes altus, Henicorhynchus siamensis, Hampala macrolepidota, Mystacoleucus marginatus, Notopterus notopterus, Pristolepis fasciatus, Anabas testudineus, Puntius brevis, Poropuntius deauratus, Cyclocheilichthys armatus, Osteochilus hasselti, Labiobarbus spilopleura, Lobocheilus davisi and Rasboratornieri. The fish were caught during the rainy season (June-September 2007) in the Chiang Mai water reservoirs (Mae Ngad and Mae Kuang) and the Chiang Rai water reservoirs (Nong Luang and Mae Tak).
Results: The prevalence of heterophyid metacercariae infection at Mae Ngad, Mae Kuang, Nong Luang and Mae tak were 37.83%, 51.35%, 12.00% and 63.33%, respectively.
Conclusions: There is a high prevalence of Haplorchis metacercarial infection in cyprinoid fish. The highest intensity of heterophyid metacercariae infection in Barbodes gonionotus was in Mae Kuang at 104.