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Population biology of helminth infections of veterinary importance and its relevance to control

  • Gary Smith
Part of the Monographiae Biologicae book series (MOBI, volume 67)

Abstract

This chapter examines how mathematical models can be helpful in the design and evaluation of control programs directed against the debilitating and sometimes fatal diseases that arise when domestic ruminants are infected with helminth parasites. The models comprise hypotheses about the natural processes which control and regulate parasite abundance. The empirical description of regulatory processes is described in detail since these processes act in such a way as to confine parasite population density between certain bounds and so tend to work in opposition to disease control strategies.

It is demonstrated that models can rank strategies in order of efficacy — at least in parasitological terms — but currently give no good indication of how much better one strategy might be than another in terms of the things that most interest the farmer: the net return on his investment in parasite control, and the risk associated with that investment. It is argued that the proper use of the models described here is not to replace anthelmintic field trials but rather as tools to guide our thinking, a means of refining judgments about the strategies most likely to work, and a framework for the development of new methods of disease control. Models should reduce the number of field trials required to evaluate the possible permutations of some new strategy because we will already have some very good idea of which will work best.

Keywords

Population Biology Helminth Infection Parasite Burden Helminth Parasite Parasite Abundance 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Literature cited

  1. Anderson, N., J. Abrmour, R. M. Eadie, W. F. H. Jarrett, F. N. Jennings, J. S. D. Ritchie, and G. M. Urquhart. 1966. Experimental Ostertagia ostertagi infections in calves: results of single infection with five graded dose levels of larvae. American Journal of Veterinary Research 27:1259–1265.Google Scholar
  2. Anderson, N., R. S. Morris, and I. K. McTaggart. 1976. An economic analysis of two schemes for the anthelmintic control of helminthiasis in weaned lambs. Australian Veterinary Journal 52:174–180.PubMedGoogle Scholar
  3. Anderson, R. M. and J. F. Michel. 1977. Density dependent survival in populations of Ostertagia ostertagi. International Journal for Parasitology 7: 321–329.PubMedCrossRefGoogle Scholar
  4. Armour, J. and C. P. Ogbourne. 1982. Bovine Ostertagiasis: a review and annotated bibliography. Miscellaneous publication No. 4., Commonwealth Institute of Parasitology.Google Scholar
  5. Barger, LA. (1982) Helminth parasites and animal production. In, Biology and Control of Endoparasites. (ed. by L. E. A. Symons, A. D. Donald, J. K. Dineen) Academic Press, Sydney, pp 133–156.Google Scholar
  6. Berry, C.I. and J. D. Dargie. 1976. The role of host nutrition in the pathogenesis of ovine fascioliasis. Veterinary Parasitology 2: 317–332.CrossRefGoogle Scholar
  7. Boray, J. C. 1969. Studies on experimental infections with Fasciola hepatica with particular reference to fascioliasis in sheep. Advances in Parasitology 7: 95–210.PubMedCrossRefGoogle Scholar
  8. Campbell, W. C. 1986. The chemotherapy of parasitic infections. Journal of Parasitology 72: 45–61.PubMedCrossRefGoogle Scholar
  9. Cole, H. H. and M. Ronning. 1974. Animal Agriculture. W. H. Freeman and Co., San Francisco.Google Scholar
  10. Donald, A. D. 1985. New methods of drug application for control of helminths. Veterinary Parasitology 18:121–137.PubMedCrossRefGoogle Scholar
  11. Gaafar, S. M. (ed.). 1983. Morantel Sustained Release Bolus. Special Issue of Veterinary Parasitology 12: 215–362.Google Scholar
  12. Gettinby, G., K. Bairdon, J. Armour, and C. Benitez-Usher. 1979. A prediction model for bovine ostertagiasis (Ostertagia ostertagi) Veterinary Record 105: 57–59.PubMedCrossRefGoogle Scholar
  13. Gettinby, G. and W. P. Gardiner. 1980. Disease incidence forecasts by means of climatic data. Biometeorology 7: 87–103.Google Scholar
  14. Grenfell, B. T. and G. Smith. 1983. Population biology and control of ostertagiasis in first year grazing calves. Proceedings of the Society for Veterinary Epidemiology and Preventive Medicine (Southampton 12–13 April, 1983) pp 70–77.Google Scholar
  15. Grenfell, B.T., G. Smith, and R. M. Anderson. 1986. Maximum likelihood estimates of survival and migration rates of the infective stages of Cooperia oncophora and Ostertagia ostertagi. Parasitology 92, 643–652.PubMedGoogle Scholar
  16. Grenfell, B. T., G. Smith, and R. M. Anderson. 1987a. The regulation of Ostertagia ostertagi in calves: The effects of past and current experience of infection on proportional establishment and parasite survival. Parasitology 95: 363–372.PubMedGoogle Scholar
  17. Grenfell, B. T., G. Smith, and R. M. Anderson. 1987b. A mathematical model of the population biology of Ostertagia ostertagi in calves and yearlings. Parasitology 95: 389–406.PubMedGoogle Scholar
  18. Hawkins, CD. and R. S. Morris. 1978. Depression of productivity in sheep infected with Fasciola hepatica. Veterinary Parasitology 4: 341–351.Google Scholar
  19. Hope-Cawdery, M. J., G. Gettinby, and J. N. R. Grainger. 1978. Mathematical models for predicting the prevalence of liver fluke disease and its control from biological and meteorological data. In. Weather and Parasitic Animal Disease. W.H.O. Technical Note No. 159. (ed. T. E. Gibson), 21–39.Google Scholar
  20. Michel, J. F. 1963. the phenomenon of host resistance and the course of infection of Ostertagia ostertagi in calves. Parasitology 53:63–84.Google Scholar
  21. Morris, R. 1969. Assessing the economic value of veterinary services to the primary industries. Australian Veterinary Journal 45: 295–300.PubMedGoogle Scholar
  22. Ollerenshaw, C. B. 1966. The approach to forecasting the incidence of fascioliasis over England and Wales 1958–1962. Agricultural Meteorology, 3: 35–63.CrossRefGoogle Scholar
  23. Ollerenshaw, C. B. 1974. Forecasting liver fluke disease. In. The effects of Meteorological Factors upon Parasites. Symposium of the British Society for Parasitology Vol. 12. (ed. A. R. Taylor, and R. Muller) Blackwell Scientific Publications.Google Scholar
  24. Ollerenshaw, C.B., E.G. Graham, and L.P. Smith. 1978. Forecasting the incidence of parasitic gastroenteritis in lambs in England and Wales. Veterinary Record 103:461–465.PubMedCrossRefGoogle Scholar
  25. Over, H. J. and J. Dijkstra. 1975. Infection rhythm in fascioliasis, In Facts and Reflections II (Lelystad Workshop on Fascioliasis) (ed. H. J. Over and J. Armour).Google Scholar
  26. Paton, G., R. J. Thomas, and P. J. Waller. 1984. A prediction model for parasitic gastroenteritis in lambs. International Journal for Parasitology 14:439–445.PubMedCrossRefGoogle Scholar
  27. Roberts, M. G., J. R. Lawson, and M. A. Gemmel, M. A. (1987) Population dynamics in echinococcosis and cysticercosis: mathematical model of the life-cycles of Taenia hydatigena and T. ovis. Parasitology 94, 181–197.PubMedGoogle Scholar
  28. Ross, J. G. 1967. An epidemiological study of fascioliasis in sheep. Veterinary Record 80: 214–217.Google Scholar
  29. Smith, G. 1982. An analysis of variations in the age structure of Fasciola hepatica populations in sheep. Parasitology 84: 49–61.PubMedGoogle Scholar
  30. Smith, G. 1984a. Analysis of anthelmintic trial protocols using sheep experimentally or naturally infected with Fasciola hepatica. Veterinary Parasitology 16: 83–94.PubMedCrossRefGoogle Scholar
  31. Smith, G. 1984b. Chemotherapy of ovine fascioliasis: use of an analytical model to assess the impact of a series of discrete doses of anthelmintic on the prevalence and intensity of infection. Veterinary Parasitology 16: 95–106.PubMedCrossRefGoogle Scholar
  32. Smith, G. 1984c. The impact of repeated doses of an anthelmintic on the intensity of infection and age structure of Fasciola hepatica populations in sheep. Veterinary Parasitology 16: 107–115.PubMedCrossRefGoogle Scholar
  33. Smith, G. 1984d. Density dependent mechanisms in the regulation of Fasciola hepatica populations in sheep. Parasitology 88:449–461.PubMedGoogle Scholar
  34. Smith, G. 1988. The population biology of the parasitic stages of Haemonchus contortus. Parasitology 96: 185–195.PubMedGoogle Scholar
  35. Smith, G. and B. T. Grenfell. 1985. The population biology of Ostertagia ostertagi. Parasitology Today 1: 76–81.PubMedCrossRefGoogle Scholar
  36. Smith, G. and D. T. Galligan. 1988. Mathematical models of the population biology of Ostertagia ostertagi and Teladorsagia circumcincta, and the economic evaluation of disease control strategies. Veterinary Parasitology 27: 73–83.PubMedCrossRefGoogle Scholar
  37. Smith, G., B. T. Grenfell, and R. M. Anderson. 1986. Development and survival of the non-infective free living stages of Ostertagia ostertagi. Parasitology 92: 471–482.PubMedCrossRefGoogle Scholar
  38. Smith, G., B. T. Grenfell, and R. M. Anderson. 1987a. The regulation of Ostertagia ostertagi populations in calves: density dependent control of fecundity. Parasitology 95: 373–388.PubMedGoogle Scholar
  39. Smith, G., B. T. Grenfell, R. M. Anderson, and J. B. Beddington. 1987b. Population biology of Ostertagia ostertagi and anthelmintic strategies against ostertagiasis in calves. Parasitology 95:407–420.PubMedGoogle Scholar
  40. Thomas, R.J. and J. R. Starr. 1978. Forecasting the peak of gastrointestinal nematode infection in lambs. Veterinary Record 103:465–468.PubMedCrossRefGoogle Scholar
  41. Wilson, R. A., G. Smith, and M. R. Thomas. 1982. Fascioliasis. In, Population Dynamics of Infectious Diseases: Theory and Applications (ed. by R. M. Anderson). Chapman and Hall, London, pp. 262–304.Google Scholar

Copyright information

© Kluwer Academic Publishers 1992

Authors and Affiliations

  • Gary Smith
    • 1
  1. 1.Section of Animal Health EconomicsUniversity of Pennsylvania, School of Veterinary MedicineKennett SquareUSA

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