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Self-cure of Haemonchus contortus infections under field conditions

Published online by Cambridge University Press:  06 April 2009

E. W. Allonby  and
G. M. Urquhart
E. W. Allonby
Affiliation:
Wellcome Laboratories for Experimental Parasitology, The University of Glasgow, Scotland
G. M. Urquhart
Affiliation:
Wellcome Laboratories for Experimental Parasitology, The University of Glasgow, Scotland
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Extract

The phenomenon of self-cure, as it occurred under field conditions in East Africa, was studied in Merino sheep infected with Haemonchus contortus. The onset of self-cure, as judged by a dramatic fall in faecal egg counts, was found to be simultaneous in sheep grazing on infected pasture and in sheep grazing on parasite-free pasture. Furthermore the results of autopsies carried out before and after self-cure showed that a marked and equal loss of adult worm burdens had also occurred. These results indicate that self-cure of H. contortus infections under natural conditions occurs in the absence of reinfection and is apparently non-immunological in origin. Since the phenomenon was always associated with a period of significant rainfall, it is suggested that new growth of pasture may be a significant aetiological factor.

Type
Research Article
Information
Parasitology , Volume 66 , Issue 1 , February 1973 , pp. 43 - 53
Copyright
Copyright © Cambridge University Press 1973

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