Immunization of swine against Trichinella spiralis.

Swine were immunized with partially purified stichosome antigens derived from Trichinella spiralis muscle larvae. In 3 trials, 500 to 600 micrograms of the solubilized particle component (S3) induced moderate levels of resistance to challenge inoculation; the percent reduction in larvae per gram of muscle ranged from 43 to 55. The effect of immunization with S3 on pig intestinal expulsion of adult worms was determined in one experiment and the results indicated that S3 immunization was only weakly effective in enhancing gut expulsion. These results suggest that immunization with S3 induces a protective immune response in the pig that may be directed either against the migrating newborn larvae or against adult worm fecundity.