Ecological border of distribution of Trichinella nativa Britov et Boev, 1972 and T. nelsoni Britov et Boev, 1972.

According to the received data Trichinella nelsoni and T. nativa occupied different areas. T. nelsoni was localized in Africa and Mediterranean subregion of Palearctics, T. nativa occupied the continental territory of Eurasia and Neoarctics. Their distribution was limited by the threshold action of certain gradation of low temperatures. The joints of the species borders passed along the isotherm line of -5 - -6 degrees of January, where they made sympatric populations. Outside of this border these species were registered as allopatric populations.