RESUMEN
The biological properties of the isolate from Trichinella from ajackal in the North-Caucasian Region of the Russian Federation were studied. The jackal's muscle tissue showed two Trichinella species preserving their genetic isolation during 5 passages on mice. Oval capsules containing live larvae (on day 90 after infection) in the rat muscles corresponds to the conventional description of the species Trichinella spiralis in their morphometric and biological properties. The morphological data, biological properties, and poor adaptation of round capsule-enclosed parasites to rats indirectly show their affiliation to the other Trichinella species--T. native or T. britovi. There was a negative test for outbred albino rat muscle Trichinella resistance to freezing, which, might be associated with the poor adaptation of this Trichinella isolate to this species of rodents.