ABSTRACT
The fish tapeworm, Diphyllobothrium latum, occurs mainly in the temperate and subarctic regions of the Northern Hemisphere. A focus for human diphyllobothriasis has for a long time been the eastern and southern Baltic region and adjacent areas of Russia. In addition to the final host, principally man, the life cycle of this parasite includes two obligatory intermediate hosts, that is, a planktonic copepode and a fish. The infective larva developes in the muscles and visceral organs of the fish and is transmitted to man when fish products are eaten raw or without proper treatment. Thus, dietary habits are decisive for the spread of the disease, which gives diphyllobothriasis its nature of an endemic disease. Most carriers of fish tapeworm infection are symptomless or suffer very little discomfort. The most serious effect induced by the parasite is tapeworm anaemia, which is of the pernicious type. In addition to hematological changes the tapeworm anaemia is frequently accompanied by neurological symptoms. Expulsion of the parasite is easily achieved with drugs today and usually leads to complete remission. It is emphasized that campaigns aiming at reducing or eliminating diphyllobothriasis from endemic areas should primarily focus on educational work in order to prevent transmission of the infective larvae from fish to man.
