World distribution of Trichinella spp. infections in animals and humans.

The etiological agents of human trichinellosis show virtually worldwide distribution in domestic and/or wild animals, with the exception of Antarctica, where the presence of the parasite has not been reported. This global distribution of Trichinella and varying cultural eating habits represent the main factors favouring human infections in industrialised and non-industrialised countries. Human trichinellosis has been documented in 55 (27.8%) countries around the world. In several of these countries, however, trichinellosis affects only ethnic minorities and tourists because the native inhabitants do not consume uncooked meat or meat of some animal species. Trichinella sp. infection has been documented in domestic animals (mainly pigs) and in wildlife of 43 (21.9%) and 66 (33.3%) countries, respectively. Of the 198 countries of the world, approximately 40 (20%) are small islands far from the major continents, or city-states where Trichinella sp. cannot circulate among animals for lack of local fauna (both domestic and wild). Finally, information on the occurrence of Trichinella sp. infection in domestic and/or wildlife is still lacking for 92 countries.