[Intrastrain heterogeneity of Trichinella spiralis: a sedimentation analysis]

Intrastrain heterogeneity of muscular larvae of trichinellids has been revealed in experiments of free sedimentation and isopyknic division in the density gradient of saccharose, the presence of which is confirmed by the study of morphological characters and infection activity. The presence of intrastrain heterogeneity indicates the necessity of introduction of standard technique for studies of biological characters of different strains of trichinellids.