Molecular epidemiology of Trichinella spp. in three Baltic countries: Lithuania, Latvia, and Estonia

Meat of domestic pigs and wild boars has been the significant source of emerged human trichinellosis in Lithuania, Latvia, and Estonia over the past two decades. However, there is very little known on the occurrence of Trichinella spp. in main wildlife reservoirs and its transmission in domestic and sylvatic cycles in these countries. The present study demonstrated considerably higher endemicity of Trichinella spp. in main sylvatic reservoirs (28.9-42% in foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) in all three countries than previously reported. Molecular identification of Trichinella larvae from more than 500 sylvatic and domestic animals revealed four Trichinella species (Trichinella spiralis, Trichinella britovi, Trichinella nativa, and Trichinella pseudospiralis) sympatric in a relatively small area and several as the first records for the respective countries. The nonencapsulating T. pseudospiralis is found for the first time in the Eastern Europe. Sylvatic T. britovi was found in domestic pigs in Lithuania and Latvia (16 and 57.1%, respectively) and only in these countries, domestic T. spiralis was detected in sylvatic animals in areas where domestic trichinellosis was registered. The study suggests that transmission of Trichinella between domestic and sylvatic cycles in Lithuania and Latvia is favored by improper human behavior, e.g., pig and slaughter waste management.