Trichinella species circulating in wild boar (Sus scrofa) populations in Poland

Hunting in Poland has a long tradition and became more popular after 1990. Each year over 60,000 wild boar are hunted. Some of them may act as Trichinella carriers thus all carcasses of wild boar are systematically sampled in game-handling establishments as part of the post-mortem examination. The aim of the study was to determine the species of Trichinella and to evaluate the year to year differences in the occurrence of those species in the populations of wild boar in Poland. Samples for the study were provided by the Veterinary Inspection Service. Wild boar carcasses were examined using a digestion method. Only samples recognized as positive for Trichinella in these examinations were sent to the National Reference Laboratory (NRL) for confirmation of genus identity. Samples from 450 animals were obtained for the study (380 muscle samples and 70 larval isolates preserved in 90% ethyl alcohol). Tissue samples were digested to isolate larvae. Extracted larval DNA was amplified using a modified multiplex PCR protocol to identify the species of Trichinella. Five larvae from each sample were examined by PCR. The study revealed that Trichinella spiralis and Trichinella britovi are present in wild boar in Poland in a ratio of 3:1. Mixed infections with T. spiralis and T. britovi were found in 1% of the animals.