Trichinella spiralis: effects on the host-parasite relationship in mice of BCG (attenuated Mycobacterium bovis).

GROVE, D. I., AND CIVIL, IL H. 1978. Trichinella spiralis: Effects on the host-parasite relationship in mice of BCG (attenuated Mycobacterium bovis). Experimental Parasitology 44, 181-189. The effects of BCG (Bacillus Calmette-Guerin, i.e., attenuated Mycobacterium bovis) on the host-parasite relationship in murine trichinosis were examined. A total of 2 X 10’ colony forming units of BCG given iv 1 week prior to Trichirda spiralis infection delayed the expulsion of adult worms from the gut. The suppression of adult worm elimination was proportional to the dose of BCG given. This finding was associated with a reduction in the degree of partial’ villous atrophy induced in the small bowel by T. spiralis. Adult female worms were fecund when they were examined 1, 2, and 3 weeks after infection of mice with T. spiralis. Despite the prolongation of fecund adult worms in the gut, there were no significant differences in muscle larval counts 4 and 6 weeks after infection. When newborn larvae were cultivated in vitro and injected iv, there was a significant 25% reduction in larval numbers recovered from the muscles of BCG-treated mice 4 weeks later. The administration of BCG had no effect on the inflammatory reaction around larvae in the muscles 4 and 6 weeks after infection. It is conchrded that BCG alters the host-parasite relationship producing retention of adult worms in the gut, reduction in the severity of partial villous atrophy, and increased nonspecific resistance to the systemic larval phase of this parasite. INDEX DESCRIPTORS: Trichinella spiralis; Nematode; Adult worms; Newborn larvae; Trichinosis; Mouse; Partial vilbus atrophy; Nonspecific resistance; BCG = Bacillus Calmette-Guerin = attenuated Mycobacterium bovis.