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The development and overwintering survival of free-living larvae of Haemonchus contortus in Sweden

  • K. Troell (a1), P. Waller (a1) and J. Höglund (a1)

Abstract

Five complimentary studies were undertaken with the overall aim to examine the ability of free-living stages of Haemonchus contortus to over-winter and tolerate cold stress. Two studies deal with the development and long-term survival of eggs and infective larvae of two geographically different isolates (Kenya and Sweden). Eggs and larvae were monitored in climatic chambers at temperatures that fluctuated daily between −1°C and 15°C, or at constant temperatures of 5°C and 15°C. The development from egg to larvae was dependent on temperatures over 5°C. The long time survival was favoured at lower temperatures. Furthermore, the overwintering capacity of the free-living stages of these isolates was estimated under Swedish field conditions. Two groups of lambs were experimentally infected with different isolates, and kept separated on previously ungrazed plots. In early May the following year, two parasite-naive tracer lambs were turned out on each of the plots to estimate the pick up of overwintered larvae. This experiment was replicated in central and southern Sweden. In addition, two experiments were performed in 2003 on pasture previously grazed by naturally infected sheep. One trial was on a pasture in southern Sweden grazed by a commercial flock, where extreme numbers of H. contortus were found towards the end of the grazing season 2002. The other study was on a pasture plot in central Sweden grazed by a hobby flock in 2002, where three of six lambs died due to haemonchiasis. Overwintered H. contortus was recorded on three of four experimental sites. Worm burdens were in all instances extremely low. No differences in development and survival were found between the isolates. Consequently, overwintering on pasture is of no practical significance in the transmission of H. contortus between grazing-seasons in Sweden.

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*Author for correspondence Fax: +46 18 30 91 62 E-mail: Johan.Hoglund@sva.se

References

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Crofton, H.D. (1965) Ecology and biological plasticity of sheep nematodes. I. The effect of temperature on the hatching of eggs of some nematode parasites of sheep. Cornell Veterinarian 55, 242250.
Donald, A.D., Morley, F.H.W., Waller, P.J., Axelsen, A. & Donnelly, J.R. (1978) Availability to grazing sheep of gastrointestinal nematode infection arising from summer contamination of pastures. Australian Journal of Agricultural Research 29, 189204.
Dobson, R.J., Waller, P.J. & Donald, A.D. (1990) Population dynamics of Trichostrongylus colubriformis in sheep: the effect of infection rate on the establishment of infective larvae and parasite fecundity. International Journal for Parasitology 20, 347352.
Gordon, H.M. (1948) The epidemiology of parasitic diseases, with special reference to studies with nematode parasites of sheep. Australian Veterinary Journal 24, 1744.
Gordon, H.M. & Whitlock, H.V. (1939) A new technique for counting nematode eggs in sheep faeces. Journal of the Council of Scientific and Industrial Research 12, 5052.
Levine, N.D. (1963) Weather, climate, and the bionomics of ruminant nematode larvae. Advances in Veterinary Science and Comparative Medicine 19, 215261.
Lindqvist, A., Ljungström, B.L, Nilsson, O. & Waller, P.J. (2001) The dynamics, prevalence and impact of nematode infections in organically raised sheep in Sweden. Acta Veterinaria Scandinavica 42, 377389.
Pearce, E.A. & Smith, C.G. (2000) The Hutchinson World weather guide. 453 pp. OxfordHelicon.
Rose, J.H. & Small, A.J. (1982) Observations on the development and survival of the free-living stages of Hyostrongylus rubidus both in their natural environments out-of-doors and under controlled conditions in the laboratory. Parasitology 85, 3343.
Rose, J.H. & Small, A.J. (1984) Observations on the bionomics of the free-living stages of Trichostrongylus vitrinus. Journal of Helminthology 58 4958.
Rossanigo, C.E. & Gruner, L. (1995) Moisture and temperature requirements in faeces for the development of free-living stages of gastrointestinal nematodes of sheep, cattle and deer. Journal of Helminthology 69, 357362.
Rudby-Martin, L. (2002) Haemonchus -läget. Fårskötsel 1213 (in Swedish).
Silverman, P.H. & Campbell, J.A. (1959) Studies on parasitic worms of sheep in Scotland I. Embryonic and larval development of Haemonchus contortus at constant conditions. Parasitology 49, 2338.
Tharaldsen, J. (1976) The epidemiology of trichostrongylid infections in young cattle in Norway. Acta Veterinaria Scandinavica Supplementum 121.
Troell, K., Mattsson, J.G., Alderborn, A. & Höglund, J. (2003) Pyrosequencing analysis identifies discrete populations of Haemonchus contortus from small ruminants. International Journal for Parasitology 33, 765771.
Waller, P.J., Rudby-Martin, L., Ljungström, B.L & Rydzyk, A. (2004) The epidemiology of abomasal nematodes of sheep in Sweden, with particular reference to overwinter survival strategies. Veterinary Parasitology 122, 207220.

The development and overwintering survival of free-living larvae of Haemonchus contortus in Sweden

  • K. Troell (a1), P. Waller (a1) and J. Höglund (a1)

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