Trichinella infection of wild carnivorans in Primorsky Krai, Russian Far East

Abstract

Nematodes of the genus Trichinella cause trichinosis, which is a zoonotic disease of humans, wild and domestic animals. In the Russian Far East, trichinosis has a natural focal character. Carnivorans (Carnivora), living in natural ecosystems including Protected Areas, are the main hosts of Trichinella. The peculiarities of Trichinella circulation in natural environment and the parasite prevalence in wild animals of different species remain poorly understood as well as the species composition of the Trichinella genus in the studied region. Muscle samples were obtained from 731 specimens belonging to 14 species and four families (Mustelidae, Ursidae, Felidae, and Canidae) in Primorsky Krai (Russia) in 2010–2020 and examined on Trichinella. The parasites were found in 124 specimens belonging to 11 species. The highest Trichinella prevalence was observed in Vulpes vulpes (64%), Ursus arctos (57%), and Lynx lynx (50%). A relatively high ratio of infected animals (30–50%) was found in Nyctereutes procyonoides, Ursus thibetanus, and Prionailurus bengalensis. The parasite prevalence was relatively low in the representatives of the Mustelidae family. Three species of the genus Trichinella (T. nativa, T. spiralis, and T. pseudospiralis) were found for carnivorans inhabiting the study area. Trichinella nativa was found the most frequently in natural ecosystems. Trichinella pseudospiralis was discovered for the first time both for P. bengalensis and for the area of the Primorsky Krai. The Carnivora ecology contributes to a high risk of infection by Trichinella species. The parasite prevalence was high in the species that combined different feeding habits, i.e. they acted as predators, scavengers and cannibals. A relatively long life expectancy also contributed to a higher risk of infection. A relatively high parasite prevalence of Trichinella in wild animals in the Primorsky Krai was caused by the high biological diversity of carnivorans. Our results are important for understanding the trichinosis circulation in natural communities and the possibility of human infestation. These data are also important for managing the carnivorans' populations in the Russian Far East. The issues of nature conservation in regard to the trichinosis circulation are also important for threatened animals, including Panthera tigris altaica.

Keywords

• animal ecology
• nematode
• parasite prevalence
• parasites
• predator
• trichinosis