Inhibited development of Ostertagia spp. and Cooperia spp. in naturally acquired infections in calves

Authors: Brunsdon RV
Publication: New Zealand Veterinary Journal, Volume 20, Issue 10, pp 183-189, Oct 1972
Publisher: Taylor and Francis

Animal type: Cattle, Livestock, Production animal, Ruminant
Subject Terms: Parasites - internal, Nematode, Growth/development
Article class: Scientific Article

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Abstract: Inhibition of the development of the larval stages of parasitic nematodes in their final host is a common phenomenon in many host/parasite systems and the fact that the inhibited forms are capable, at a later stage, of resuming their development has been recognized for some time (for reviews see Armour et al 1969a; Michel, 1971). Inhibited development of Ostertagia ostertagi, in both experimental and naturally acquired infections, has been reported frequently and the practical importance of the phenomenon well established (Martin et al 1957; Vegors, 1958; Michel, 1963; Ross, 1963, 1965; Anderson et al 1965; Hotson, 1967; Armour et al 1969a, b). In this species, inhibition occurs at the early 4th larval stage and, although up to several hundreds of thousands of these forms may accumulate in the abomasal mucosa, they do not cause disease. The larvae are capable of eventually resuming their development and usually do so in small numbers to replace adult worms that are lost (Michel, 1971). However, occasionally, in circumstances that are not clearly understood, massive numbers may resume their development simultaneously and so precipitate clinical disease…

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