RESUMEN
In the course of experiments in was found out that golden hamsters having the bilious duct operationally blocked display receptivity to the infection with the non-excysted Opisthorchis felineus metacercariae passed to the stomach. Excysted metacercariae injected to the system of the portal vein settle down in the bilious pathways of the liver and develop there up to the adult stage. In vitro, the metacercariae survive in the blood serum of the intact golden hamsters during one day. Based on the experiments, it is hypothesized that the early stage of O. felineus infection in the bilious duct of definitive hosts is performed by means of hematogenic migration of metacercariae through the portal veins system from the mucous layer of the alimentary tract of the host.