Influence of host hormones on nematode parastism in rabbits, Oryctolagus cuniculus (L.)

Abstract

The presence of an oestrogen implant significantly increased the numbers of Trichostrongylus retortaeformis naturally acquired by grazing rabbits of both sexes. The injection of luteinizing hormone at 18-day intervals to induce pseudopregnancies in the pre-breeding period caused a reduced number of T, retortaeformis to be acquired by grazing females relative to that acquired by normal females and males. The experimental manipulations did not influence numbers of Graphidium strigosum in the same rabbits; but numbers of G. strigosum acquired by rabbits in different experimental enclosures differed significantly. Progesterone decreased and ACTH increased the numbers of T. retortaeformis that matured following a standard experimental infection of previously worm-free rabbits.