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Abstract

The effects of cold storage of infective third-stage larvae (I-A) of different isolates of the parasitic nematode Haemonchus contortus,were studied with respect to infectivity, pre-patent period and propensity for larval arrestment. Two complementary experiments were Conducted with 2 groups of lambs, each animal being inoculated with 2000 L3 of either Swedish or Kenyan origin. In a first experiment, L3s were cold treated at 5 degrees C for 9 months prior to infection, whereas in a second experiment larvae were newly hatched. Individual faecal egg counts (FECs), and worm burdens were determined for each experiment. The results showed that the greatest differences were associated with the pre-treatment of larvae. The pre-patent period and the FECs differed significantly between the experiments but not between the isolates use(] in each experiment. However, the extent of hypobiosis was significantly different between the two isolates when fresh larvae were used (36%, Kenyan isolate and 70% Swedish). The storage of H. contortus at 5 degrees C had no apparent effect on the infectivity of L3s, as high establishment ranging from 43 to 74% were observed, irrespective of isolates used. This study showed that H. contortus exhibited similar phenotypic traits regardless of geographical origin. Thus, there was limited evidence for adaptations to temperate climatic conditions.

Keywords

Haemochus contortus; cold storage; larval inhibition; pre-patent period; establishment

Published in

Parasitology
2006, volume: 132, pages: 403-409
Publisher: CAMBRIDGE UNIV PRESS

SLU Authors

UKÄ Subject classification

Veterinary Science
Animal and Dairy Science

Publication identifier

  • DOI: https://doi.org/10.1017/S0031182005009182

Permanent link to this page (URI)

https://res.slu.se/id/publ/10052