Occurrence of Trichinella Species in Wild Boar (Sus scrofa) Populations Across Bulgaria.

Trichinellosis is a natural-focal helminthic zoonosis that affects the skeletal muscle tissue of carnivorous and omnivorous wild and domestic animals. In Europe, four prevalent species belonging to the genus Trichinella have been identified: T. spiralis, T. britovi, T. nativa and T. pseudospiralis. The aim of this study was to identify the Trichinella species circulating in wild boar populations in Bulgaria, and to evaluate their prevalence. The research covered five hunting seasons, from October 2020 to February 2025. A total of 43,228 wild boar carcasses were examined using artificial digestion, and 597 tested positive, corresponding to a prevalence of 1.5%. The Trichinella isolates were identified at the species level by multiplex PCR at the European Union Reference Laboratory for Parasites in Rome, Italy. Among the samples suitable for molecular identification, Trichinella britovi was the only species detected in wild boar in Bulgaria during the study period, although other Trichinella species, including T. spiralis and T. pseudospiralis, have occasionally been reported in this host in earlier investigations. Geographical distribution analysis showed that most infected wild boar originated from southern part of the country.