Trichinellosis of animals in Chukotka, USSR: A general review

During an examination, for trichinellosis, of 1489 mammals of 12 different species, in the territory of Chukotka National district (regions of Anadyr', Bering, Iul'tin, Chaun and Chukotka) and in the region of North-Even of Magadan province, Trichinella larvae were detected in 236 (16·4%) of these animals from 6 of the species: in 109 (44·8%) of the blue polar foxes kept in cages, in 12 (15·8%) of the silver-black foxes kept in cages, in 84 (18·2%) of the white polar foxes, in 17 (17·5%) of the common foxes, in 13 (12·1%) of the dogs and in the one European bear examined. Trichinella larvae were not found in 190 marine mammals examined: 178 ringed seals, 7 whales, 4 walruses, and 1 bearded seal, nor in the 8 Siberian squirrels and 159 domestic pigs examined. The high incidence of Trichinella infection amongst blue polar foxes and silver-black foxes on fur-animal farms in Chukotka, where the food ration of these animals is predominately the flesh of marine mammals (walruses and other pinnipeds), suggests that marine mammals may constitute one of the sources of infection to caged animals. In Chukotka, as in other regions of the Extreme North and North-East, the circulation of trichinae in nature may occur between two ecologically different groups of animals: terrestial and marine mammals. A wide distribution of trichinellosis among animals in nature, or kept in cages and among dogs in Chukotka National district and in the North-Even region of Magadan province provides a constant threat of infection to man. Thus the flesh and sub-products of potential hosts of trichinae (including dogs, fur animals, European and polar bears, marine mammals, etc.) should undergo thorough trichinelloscopy examination before being consumed by man. The flesh of sea mammals should be examined for trichinellosis before being used as food for animals; the presence of trichinae in it requires its sterilization.