Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-27T00:20:18.677Z Has data issue: false hasContentIssue false
  • English
  • Français

Epidemiology of nematode infections of Soay sheep (Ovis aries L.) on St Kilda

Published online by Cambridge University Press:  06 April 2009

F. M. D. Gulland  and
M. Fox
F. M. D. Gulland
Affiliation:
Large Animal Research Group, Zoology Department, University of Cambridge, Downing Street, Cambridge CB2 3EJ
M. Fox
Affiliation:
Royal Veterinary College, Royal College Street, Camden Town, London NW1
Get access Rights & Permissions [Opens in a new window]

Summary

The epidemiology of nematode infections of Soay sheep on the island of St Kilda over a period of 2 years (August 1988–August 1990) spanning a host population crash is described. Infective larvae (L3) levels on pasture were high (2422±365 L3/kg D.M. grass in midsummer 1988) when host population density was high, decreasing after the sheep population declined by 70% in early 1989 (601 ±14 L3/kg D.M. in midsummer 1989). The availability of infective larvae to sheep increased during the winter of 1988–1989, probably as a result of concentration of existing larvae on grass as vegetation was destroyed by bad weather and overgrazing. Increased availability of pre-parasitic stages was accompanied by a marked increased in faecal egg counts from sheep of all ages and both sexes. Prevalence and intensity of infection (faecal egg counts) were higher in males than females throughout the 2-year study (χ2 = 208.3, P < 0.005 and F1.2000 = 304, P < 0.001 respectively), except during the lambing periods, and decreased with age in both sexes. Changes in prevalence and intensity of strongyle infections were associated with changes in host population density. Prevalence and intensity of Dictyocaulus filaria larvae in faeces increased during the host population crash. Infection intensity decreased with age (F1.203 = 44.02, P < 0.001) and was higher in males than females (F1.203 = 13.45, P < 0.001).

Keywords

epidemiologySoay sheepnematode infectionsprevalenceintensity
Type
Research Article
Information
Parasitology , Volume 105 , Issue 3 , December 1992 , pp. 481 - 492
Copyright
Copyright © Cambridge University Press 1992

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Albon, S. D., Mitchell, B., Huby, B. J. & Brown, D. (1986). Fertility in female Red deer (Cervus elaphus): the effects of body composition, age and reproductive success. Journal of Zoology 209, 447–60.Google Scholar
Anderson, R. M. & Crombie, J. A. (1984). Experimental studies of age-prevalence curves for Schistosoma mansoni infections in populations of Biomphalaria glabrata. Parasitology 89, 79–105.CrossRefGoogle ScholarPubMed
Anderson, R. M. & May, R. M. (1978). Regulation and stability of host–parasite population interactions. I. Regulatory processes. Journal of Animal Ecology 47, 219–47.Google Scholar
Anderson, R. M. & May, R. M. (1979). Population biology of infectious diseases: Part I. Nature, London 280, 361–7.CrossRefGoogle ScholarPubMed
Armour, J. (1980). The epidemiology of helminth disease in farm animals. Veterinary Parasitology 6, 7–46.Google Scholar
Armour, J. (1989). The influence of host immunity on the epidemiology of trichostrongyle infections in cattle. Veterinary Parasitology 32, 5–19.Google Scholar
Barger, I. A. (1987). Population regulation in trichostrongylids of ruminants. International Journal for Parasitology 17, 531–40.Google Scholar
Boag, B. & Thomas, R. J. (1970). The development and survival of free living stages of Trichostrongylus colubriformis and Ostertagia circumcincta on pasture. Research in Veterinary Science 11, 380–1.CrossRefGoogle ScholarPubMed
Boag, B., Topham, P. B. & Webster, R. (1989). Spatial distribution on pasture of infective larvae of the gastrointestinal nematode parasites of sheep. International Journal for Parasitology 19, 681–5.CrossRefGoogle ScholarPubMed
Clutton-Brock, J. (1981). Domesticated Animals from Early Times. London: British Museum (Natural History) and Heinemann.Google Scholar
Clutton-Brock, T. H., Price, O. F., Albon, S. D. & Jewell, P. A. (1991). Persistent instability and population regulation in Soay sheep. Journal of Animal Ecology 60, 593–608.Google Scholar
Crofton, H. D. (1949). The ecology of immature stages of Trichostrongyle nematodes. III. Larval populations on hill pastures. Parasitology 39, 274–80.CrossRefGoogle Scholar
Crofton, H. D. (1958). Nematode parasite populations in sheep on lowland farms. VI. Sheep behaviour and nematode infections. Parasitology 48, 251–60.CrossRefGoogle ScholarPubMed
Donald, A. D. (1967). Population studies on the infective stage of some nematode parasites of sheep. I. The frequency distribution of strongyloid infective larvae in random samples of pasture. Parasitology 57, 263–79.CrossRefGoogle ScholarPubMed
Donald, A. D. & Leslie, R. T. (1969). Population studies on the infective stage of some nematode parasites of sheep. II. The distribution of faecal deposits on fields grazed by sheep. Parasitology 59, 141–57.CrossRefGoogle ScholarPubMed
Downey, N. E. & Conway, A. (1968). Grazing management in relation to trichostrongylid infestation in lambs. 1. Influence of stocking rate on the level of infestation. Irish Journal of Agricultural Research 7, 343–62.Google Scholar
Dunsmore, J. D. & Dudzinski, M. L. (1968). Influence of numbers of nematode parasites in wild rabbits Oryctolagus cunicuius (L.), to host sex, age, and season. Journal of Parasitology 54, 462–74.CrossRefGoogle Scholar
Genstat 5 Committee (1987). Genstat 5 Reference Manual, Oxford: Oxford University Press.Google Scholar
Gettinby, G., Mckellar, Q. A., Bairden, K., Theodoris, V. & Whitelaw, A. (1985). Comparison of two techniques used for the recovery of nematode infective larvae from pasture. Research in Veterinary Science 39, 99–102.CrossRefGoogle ScholarPubMed
Gibson, T. E. (1963). Experiments on the epidemiology of Nematodiriasis. Research in Veterinary Science 4, 258–68.CrossRefGoogle Scholar
Gibson, T. E. & Everett, G. (1972). The ecology of the free living stages of Ostertagia circumcincta. Parasitology 64, 451–60.CrossRefGoogle ScholarPubMed
Grenfell, B. T. (1988). Gastrointestinal nematode parasites and the stability and productivity of intensive ruminant grazing systems. Philosophical Transactions of the Royal Society of London, B321, 541–63.Google Scholar
Grenfell, B. T., Price, O. F., Albon, S. D. & Clutton-Brock, T. H. (1992). Overcompensation and population cycles in an ungulate. Nature, London 355, 823–6.Google Scholar
Gulland, F. M. D. (1992). The role of nematode parasites in Soay sheep (Ovis aries L.) mortality during a host population crash. Parasitology 105, 493–503.CrossRefGoogle Scholar
Hansen, J. W., Nansen, P. & Foldager, J. (1981). The importance of stocking rate to the uptake of gastrointestinal nematodes by grazing calves. In Epidemiology and Control of Nematodiasis in Cattle, (ed. Nansen, P., Jorgensen, R. J. & Soulsby, E. J. L.) pp. 471–494. Brussels: ECSC, EEC, EAEC.Google Scholar
Haukisalmi, V., Henttonen, H. & Tenora, F. (1988). Population dynamics of common and rare helminths in cyclic vole populations. Journal of Animal Ecology 57, 807–25.CrossRefGoogle Scholar
Hudson, P. J., Dobson, A. P. & Newborn, D. (1985). Cyclic and non-cyclic populations of red grouse: a role for parasitism? In Ecology and Genetics of Host–Parasite Interactions, (ed. Rollinson, D. & Anderson, R. M.) pp. 79–90. London: Academic Press.Google Scholar
Jewell, P. A., Milner, C. & Boyd, J. M. (1974). Island Survivors. London: Athlone Press.Google Scholar
Keith, L. B., Cary, J. R., Yuill, T. M. & Keith, I. M. (1985). Prevalence of helminths in a cyclic snowshoe hare population. Journal of Wildlife Diseases 21, 233–53.Google Scholar
Keymer, A. E. (1981). Population dynamics of Hymenolepis diminuta in the intermediate host. Journal of Animal Ecology 50, 941–50.Google Scholar
Lancaster, M. B. (1970). The recovery of infective larvae from herbage samples. Journal of Helminthology 44, 219–30.Google Scholar
May, R. M. & Anderson, R. M. (1978). Regulation and stability of host–parasite populations. II. Destabilizing processes. Journal of Animal Ecology 47, 249–67.Google Scholar
May, R. M. & Anderson, R. M. (1979). Population biology of infectious diseases. Part II. Nature, London 280, 455–61.Google Scholar
Michel, J. F. (1976). The epidemiology and control of some nematode infections in grazing animals. Advances in Parasitology 14, 355–97.Google Scholar
Ministry of Agriculture Fisheries and Food (1971). Manual of veterinary parasitological laboratory techniques. Technical Bulletin 18, London: HMSO.Google Scholar
Reddington, J. J., Stewart, G. I., Kramer, G. W. & Kramer, M. A. (1981). The effect of host sex and hormones on Trichinella spiralis in the mouse. Journal of Parasitology 67, 548–55.CrossRefGoogle ScholarPubMed
Salih, N. E. & Grainger, J. N. R. (1982). The effect of constant and changing temperature on the development of the eggs and larvae of Ostertagia circumcincta. Journal of Thermal Biology 7, 35–8.CrossRefGoogle Scholar
Scott, M. E. (1987). Regulation of mouse colony abundance by Heligmosomoides polygyrus. Parasitology 95, 111–24.CrossRefGoogle ScholarPubMed
Scott, M. E. & Anderson, R. M. (1984). The population dynamics of Gyrodactylus bullatarudis (Monogenea) on guppies (Poecilia reticulata). Parasitology 89, 159–94.Google Scholar
Scott, M. E. & Dobson, A. (1989). The role of parasites in regulating host abundance. Parasitology Today 5, 176–83.Google Scholar
Southcott, W. E., Langlands, J. P. & Heath, D. D. (1970). Stocking density and nematode infections of grazing sheep. Proceedings of the 11th International Grassland Congress, Australia, pp. 888–890.Google Scholar
Taylor, E. L. (1939). Technique for the estimation of pasture infestation by strongyloid larvae. Parasitology 31, 473–8.Google Scholar
Uriate, J. & Valderrabano, J. (1989). An epidemiological study of parasitic gastroenteritis in sheep under an intensive grazing system. Veterinary Parasitology 31, 71–81.Google Scholar
Wakelin, D. (1987). The role of the immune response in helminth population regulation. International Journal for Parasitology 17, 549–57.Google Scholar
Weinstein, Y., Ran, S. & Segal, S. (1984). Sex associated differences in the regulation of immune responses controlled by the MHC of the mouse. Journal of Immunology 132, 656–61.Google Scholar
Yadav, C. L. (1987). The epidemiology and control of sheep nematodes. Ph.D. thesis, University of Liverpool.Google Scholar
Young, R. R., Anderson, N., Overend, D., Tweedie, R. L., Malafont, K. W. J. & Preston, G. A. N. (1980). The effect of temperature on times to hatching of eggs of the nematode Ostertagia circumcincta. Parasitology 81, 477–91.Google Scholar