[The characteristics of diphyllobothriasis foci in the Pur River basin (Yamalo-Nenets Autonomous Okrug)].

Diphyllobothriases are spread in the population of the Pur River basin unevenly. The population on the lower Pur is affected little, but that on the upper Pur and its tributaries is affected much more. This is largely accounted for by what fishes are prevalent in the diet of the local population and how they consume fish. In the past 30 years, the infection of fish with Diphyllobothrium latum larvae and the prevalence of the population's infection have reduced in some areas of the Pur River basin. Among other things, this is associated with man-made impacts on the local water reservoirs (development of areas, gas extraction, etc.), which influences the first and second intermediate D.latum hosts.