Small liver flukes, Clonorchis sinensis and Opisthorchis viverini, are fish-borne trematodes (FBTs) causing
significant public health problems in Asia. While C. sinensis is distributing mainly in far east Asia, O.
viverini is distributing in Indochina peninsula. Recently, however, the geographical distributions of those
small liver flukes were proven to be far wider than expected. Nevertheless, little is known about the
epidemiology of small liver flukes in Cambodia. The present study is, therefore, aimed at clarifying the
status of small liver fluke infections in various species of freshwater fish in southern Cambodia. A total of
1479 freshwater fish, 1316 (89%) comprised of 20 different species of the cyprinoid family and 163 (11%)
belonging to 8 families of non-cyprinoids, were collected during May 2007 and February 2008, and the
presence of small liver fluke metacercariae was examined by the compression method. Small liver fluke
metacercariae were found in 10 species of cyprinoids with the infection rate ranging 2.1–66.7% and the
mean intensity of infection of 1.0–15.0 (range: 1–65). For the speciation, adult worms were obtained by
experimental infection in hamsters. The small liver fluke found in this studywere identified as Opisthorchis
viverrini by the morphological features of adult worms, and this identification was confirmed by partial
COI sequencing of the metacercariae