The impact of refugia on the development of thiabendazole resistance in Haemonchus contortus

doi:10.1016/0020-7519(81)90023-0

International Journal for Parasitology

Volume 11, Issue 1, February 1981, Pages 35-41

https://doi.org/10.1016/0020-7519(81)90023-0 Get rights and content

Abstract

Martin P. J., Le Jambre L. F. and Claxton J. H. 1981. The impact of refugia on the development of thiabendazole resistance in Haemonchus contortus. International Journal for Parasitology11: 35–41. Beginning with a mixture of 5% thiabendazole-resistant and 95% non thiabendazole-resistant Haemonchus contortus larvae, worm free sheep were artificially infected with either 10,000, 9000, 7000, 2500 or zero larvae. Four weeks later, the infected sheep were treated with 44 mg/kg of thiabendazole. Seven days after anthelmintic treatment the same sheep were infected with zero, 1000, 3000, 7500 or 10,000 larvae respectively so that each sheep was given a total of 10,000 larvae. The larvae given after thiabendazole treatment are referred to as being in refugia (defined as an area where individual members of a population can escape exposure to a drug). This was repeated for six generations of parasites, maintaining the same proportion of larvae in refugia in each generation. The egg hatch assay for resistance indicated that refugia delayed the development of resistance in Haemonchus contortus. Where none or a small proportion of larvae were in refugia, a rapid increase in resistance occurred. With an increased proportion of larvae in refugia, resistance was slower to develop. Population size, as estimated by faecal egg counts done after anthelmintic treatment and corrected for the number of larvae given in each treatment, was lower at the higher levels of refugia. This was due to a lower level of resistance in the higher refugia lines and consequently a greater effect of the drug. However, the estimate of population size, from egg counts done after the larvae introduced from refugia had matured, were similar in all lines.

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There are more references available in the full text version of this article.

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^‡: Present address: CSIRO, Division of Animal Health, Private Bag 1, Parkville, Vic. 3052, Australia.

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International Journal for Parasitology

Abstract

References (17)

Egg hatch as an in vitro assay of thiabendazole resistance in nematodes

Veterinary Parasitology

Grazing management and control of parasites in sheep

Some observations on asymmetrical correlated responses to selection

Genetic Research

Anthelmintic activity of tetramisole, thiabendazole and purified fine particle phenothiazine against experimental infections of Haemonchus contortus and Trichostrongylus species in sheep

Field studies on parasite control in sheep: comparison of thiabendazole, ruelene, and phenothiazine

American Journal of Veterinary Research

Pesticide resistance as an evolutionary phenomenon

Genetic and biological influences in the evolution of insecticide resistance

Journal of Economic Entomology

The interpretation of insecticide resistance in terms of changes in ratio of genotypes

Cited by (91)

A journey through 50 years of research relevant to the control of gastrointestinal nematodes in ruminant livestock and thoughts on future directions

Multiple drug resistance in hookworms infecting greyhound dogs in the USA

Spread of anthelmintic resistance in intestinal helminths of dogs and cats is currently less pronounced than in ruminants and horses – Yet it is of major concern

Refugia-Based Strategies for Parasite Control in Livestock

Managing anthelmintic resistance in cyathostomin parasites: Investigating the benefits of refugia-based strategies

Parasite Control Programs