Migrations and the introduction of wild ruminants as a source of parasite exchange and emergence of new parasitoses.

The relationship between European bison and cervidae is a good model for studies on the influence of migration and introduction of new species on the helmhninthofauna of wild ruminants and the occurrence of new parasitoses. Changes in the helminthofauna of bison and deer under the influence of changes in the environment and living conditions, as well as the introduction and migration of other species, are discussed in detail. The exchange of helminths between bison, cervids and domestic ruminants is demonstrated. Examples of helminth introduction from specific Cervidae species, the formation of the new host-parasite systems and the appearance of new parasitoses are also presented.