Experimental infection in mammalian host
Two hamsters weighing 100–150 g were used as the experimental
final hosts. They were fed with commercial animal food
and kept in galvanized metal cages and were handled according to
the Animal Care and Use Protocol (Mahidol University, FTM-ACUC
007/2008). Each hamster was infected orally with 30 live metacercariae
using a polyethylene tubing connected to a 5 ml syringe. The
maturation of metacercariae into adult flukes was judged by fecal
examinations for parasite eggs 4 weeks afterwards. Infected hamsters
became fecal egg-positive at 5 weeks and were sacrificed 6
week post-infection. The gastrointestinal tract, bile duct, and other
organswere carefully examined for the presence of flukes. The adult
worms were fixed in warm 10% formalin, stained with Semichon’s
acetic carmine, and identified with the aid of morphological criteria