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

## TL;DR

This study found that Trichinella britovi is the only species infecting wild boar in Bulgaria, with a 1.5% infection rate, mainly in the south.

## Contribution

The study identifies Trichinella britovi as the sole species in Bulgarian wild boar, updating regional parasite knowledge.

## Key findings

- Trichinella britovi was the only species detected in wild boar in Bulgaria.
- Infection prevalence was 1.5% among 43,228 examined carcasses.
- Most infected boar were from southern Bulgaria.

## Abstract

Trichinellosis is a disease caused by parasitic worms that can be transmitted from animals to humans. Free-ranging wild boar play an important role in maintaining this parasite in nature and are also a potential source of human infection through the consumption of raw or undercooked meat. The aim of this study was to identify which species of this parasite are present in wild boar in Bulgaria and to determine the frequency of infection. The study was conducted over five hunting seasons, from 2020 to 2025, and more than 43,000 wild boar carcasses were examined. Approximately 1.5% of the animals were found to be infected. All positive samples belonged to a single parasite species, Trichinella britovi, even though other species have been occasionally reported in the past. Most infected wild boar originated from the southern part of the country. These findings provide valuable information for public health protection, food safety, and wildlife management by helping authorities better assess infection risk and design effective control measures.

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.