Populations of Ostertagia circumcincta in lambs following a single infection

Abstract

Populations of Ostertagia circumcincta in lambs following a single infection. International Journal for Parasitology 16: 63–67. The course of worm burdens in lambs following a single infection of 3000, 10000 or 33000 third stage larvae of Ostertagia circumcinta was studied. An initial period when the worm population remained stable was followed by one of exponential loss. Measurements of female worm length and observations on the incidence of reduced vulval flaps were used to show that the development of some of the worms was initially arrested and that subsequently adult worms which were lost were replaced by arrested forms resuming their development.