Acquired Immunity to Fasciola Hepatica in the Laboratory White Mouse

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  • Department of Biology, Eastern Washington State College, Cheney, Washington 99004


At 25 and 40 days after a challenge infection administered to mice inoculated with one or two immunizing infections, no significant difference in challenge worm burdens were observed among experimental groups. All experimental groups had significantly fewer challenge worms when compared with the natural-immunity controls at 25 and 40 days after challenge.

Immune factors responsible for the observed immunity in this system are effective between 20 and 25 days after challenge. It is suggested that the specific antigens responsible for the induction of acquired immunity are released from worms between 8 and 17 days old.