ABSTRACT
The prerequisites of the successful establishment of a given amphistome are the simultaneous presence of the worm, the susceptible intermediate, and the adequate definitive hosts. As the amphistomes show narrow specificity to their intermediate host, the fate of the amphistomes carried with the definitive hosts depends either on the degree of the specificity of the flukes or on the presence of the same or closely related intermediate hosts. There are numerous countries, islands, or other territories where domestic animals, mainly domestic ruminants, are not indigenous, and their amphistomes, undoubtedly, have been introduced by these definitive hosts, and they successfully established their populations. There are several other countries where the number of amphistomes of ruminants, besides the endemic species, was considerably increased by the introduction of domestic ruminants. The dispersal data arising from human activities show that without efficient sanitary measures, the spread of amphistome parasites is likely.
