[The strategy of a parasite is to preserve and continue its species; some trends for achieving the goal].

The authors show that the strategy of parasites, which is to preserve and continue its species is accomplished mainly by providing of a trophic substrate. Opisthorichiasis is used as an example to show that the nutriceutic biomass of cholangiocytes may be increased due to gene mutations, induced proliferation of liver stem cells, their differentiation to committed ones and cholangiocellular differon elements; moreover, the proliferative processes of mesenchymal components become active in other organs of a host. During their ontogenesis in the intermediate and final hosts, the parasites work out the mechanisms for prolonging their life span to complete a full development cycle (Margaritifera margaritifera glochidia); however, predominantly the parasite-host symbiosis is attended by the latter's lameness. Predation is one of the types of symbiotic relations.