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Seasonal change in a balanced polymorphism in Haemonchus contortus populations*

Published online by Cambridge University Press:  06 April 2009

Leo F. LeJambre  and
L. H. Ractliffe
Leo F. LeJambre
Affiliation:
New York State Veterinary College at Cornell University, Ithaca, New York 14850
L. H. Ractliffe
Affiliation:
New York State Veterinary College at Cornell University, Ithaca, New York 14850
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Extract

Twenty-one sheep were killed after having been kept for varying times on a pasture contaminated with Haemonchus contortus. The proportions of linguiform A to linguiform B phenotypes were estimated for the H. contortus populations of each sheep. They gave further evidence that the linguiform B phenotype gradually replaces the linguiform A phenotype during the summer. Given the genetic basis of the phenotype it is pointed out that this seasonal change would appear to be inconsistent with any theory stating that essentially only one generation of worms is involved in the yearly outbreaks of disease.

Type
Research Article
Information
Parasitology , Volume 62 , Issue 1 , February 1971 , pp. 151 - 155
Copyright
Copyright © Cambridge University Press 1971

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References

REFERENCES

Cole, L. C. (1954). The population consequences of life history phenomena. Quarterly Review of Biology 29, 103–37.CrossRefGoogle ScholarPubMed
Crofton, H. D. (1957). Nematode parasite populations in sheep on lowland farms. III. The seasonal incidence of species. Parasitology 47, 304–18.CrossRefGoogle ScholarPubMed
Das, K. M. & Whitlock, J. H. (1960). Subspeciation in Haemonchus contortus (Rudolphi, 1803), Nemata, Trichostrongyloidea. Cornell Veterinarian 50, 182–97.Google ScholarPubMed
Lejambre, L. F. (1970). The adaptiveness of polymorphism in Haemonchus contortus. Cornell Thesis, 1970.Google Scholar
Lejambre, L. F. & Whitlock, J. H. (1968). Seasonal fluctuation in linguiform morphs of Haemonchus contortus cayugensis. Journal of Parasitology 54, 827–30.CrossRefGoogle Scholar
Michel, J. F. (1967). Morphological changes in a parasitic nematode due to acquired resistance of the host. Nature, London 215, 520–1.CrossRefGoogle Scholar
Michel, J. F. (1969 a). Observations on the epidemiology of parasitic gastroenteritis in calves. Journal of Helminthology 43, 111–33.CrossRefGoogle ScholarPubMed
Michel, J. F. (1969 b). The epidemiology and control of some nematode infections of grazing animals. Advances in Parasitology 7, 211–82.CrossRefGoogle ScholarPubMed
Roberts, F. H. S., Turner, H. N. & Mckevett, M. (1954). On the specific distinctness of the ovine and bovine ‘strain’ of Haemonchus contortus (Rudolphi) Cobb (Nematoda: Trichostrongylidae). Australian Journal of Zoology 2, 275–95.CrossRefGoogle Scholar
Whitlock, J. H. (1963). A cybernetic approach to a natural epidemic of strongylatosis in sheep. Cornell Veterinarian 53, 505–34.Google ScholarPubMed
Whitlock, J. H. (1966). The environmental biology of a nematode. In Biology of Parasites, pp. 185–97. New York: Academic Press Inc.Google Scholar