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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

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