A cross-sectional study of Trichinella spp. infection in wolves (Canis lupus) reveals first evidence of T. spiralis in the species in Poland.

Introduction: Trichinella spp. is an important zoonotic nematode parasite which infects a variety of hosts, not only including omnivorous and carnivorous animals but also herbivores. The environment and wildlife play a crucial role in nematode circulation in Poland. Trichinella spp. are present in prey animals, and the growth in the wolf population makes them potentially one of the major reservoirs, spreaders and/or indicators of Trichinella presence in their prey. The main aims of the study were to demonstrate the prevalence of Trichinella spp. in wolves, identify the predilection sites, and evaluate the species diversity and possible risk factors.

Material and methods: Forelimb, diaphragm and tongue muscle samples from 96 wolves from all over the country were examined by microscopy and molecular identification of parasitic isolates from them was made by multiplex PCR.

Results: A total of 43 wolves (44%) were infected with Trichinella spp. For the first time, T. spiralis was detected in these animals, being noted in almost half of the cases. Trichinella spiralis infections were clustered in the north-west of the country.

Conclusion: The high Trichinella prevalence in the apex predator suggests the wolf's growing importance in the circulation and transmission of this food-borne parasite. This also indicates the importance of the disposal of carcasses to prevent the risks of animal and human exposure to this dangerous pathogen and the spread of Trichinella in a sylvatic environment.