The wild boar (Sus scrofa, Linnaeus, 1758) as an important reservoir host for Alaria alata in the Baltic region and potential risk of infection in humans

Alaria alata trematode is widely distributed throughout Europe and has a complex life cycle in which wild boar serve as a reservoir host. The primary aims of the present study are to establish the occurrence of A. alata mesocercariae in naturally infected wild boar in Latvia and to assess the risk for humans to acquire A. alata infection via consumption of wild boar meat. By summarizing long-term data using the Trichinella inspection method from 2014 to 2019, the overall A. alata prevalence was 8.3%, of which significantly higher A. alata prevalence was observed during the summer seasons. Additionally, 43.9% (n = 485) of wild boar were found to be infected with A. alata using Alaria mesocercariae migration technique. The present study indicates that the probability for humans to acquire A. alata mesocercariae is possible, yet improbable and varies from 0.2% to 2.2%. Most likely, it depends on both frequency of A. alata presence in wild boar population and of a method of preparing wild boar meat for consumption that will allow for the parasite inactivation.