Resistance of mice to Toxocara canis: effect of prechallenge infections and injections of worm extracts

Abstract

Test mice have been infected one or more times and challenged with Toxocara canis larvae in an attempt to demonstrate acquired resistance to this nematode in a paratenic host. The worm burden of these mice at necropsy was not significantly less than that for controls.Mice given prechallenge injections of somatic fractions of T. canis eggs and adult worms, together with adjuvant, were found to harbor significantly fewer larvae after a challenge infection than did controls. The worm burden of mice similarly injected with fractions of adult Ascaris lumbricoides had worm burdens after challenge which were about equal to that of controls.