Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-27T11:48:59.977Z Has data issue: false hasContentIssue false
  • English
  • Français

Worm burdens, acquired resistance and live weight gains in lambs during prolonged daily infections with Trichostrongylus colubriformis (Giles, 1892) Loos, 1905

Published online by Cambridge University Press:  06 April 2009

S. N. Chiejina  and
M. M. H. Sewell
S. N. Chiejina
Affiliation:
Department of Tropical Animal Health, Royal (Dick) School of Veterinary Studies, Roslin, Midlothian
M. M. H. Sewell
Affiliation:
Department of Tropical Animal Health, Royal (Dick) School of Veterinary Studies, Roslin, Midlothian
Get access Rights & Permissions [Opens in a new window]

Extract

Three groups of lambs, aged 3, 5 and 6 months respectively, were infected daily with 5000 infective larvae of Trichostrongylus colubriformis for periods of 15–20 weeks. Some of the lambs also received a single challenge infection at the end of week 16. The course of the infections was monitored by means of faecal egg counts, measurement of live-weight gains and regular post mortem worm counts.

There was an initial rapid increase in egg counts soon after patency, which was followed by an exponential fall in the counts in most lambs. This fall seemed to precede the expulsion of worms by a few weeks and was associated with reduced fecundity in the female worms. Furthermore, although the trend of the egg counts of some lambs suggested that a self-cure reaction had taken place, in a number of these lambs the low faecal egg counts did not reflect the size of their worm burden.

Heavy worm burdens were usually associated with clinical symptoms of trichostrongylosis, including anorexia, diarrhoea and loss of weight. As the lambs developed resistance to reinfection and expelled their worm burden a rapid clinical recovery occurred, except in a few lambs which appeared to have suffered irreversible damage from the earlier heavy worm burden.

The worm burden in most lambs appeared to be cumulative during the first 4–8 weeks before they developed a strong resistance to reinfection. There was considerable loss of the adult worm burden by 8–15 weeks after initial infection and some evidence of stunting in the remaining parasites.

The immunological control of T. colubriformis infections in these lambs was achieved by means of the development of resistance to reinfection, inhibition of the ovulation of the female worms, stunting of adult worms and expulsion of adult worms by resistant lambs. These may be separate immune phenomena requiring different thresholds of parasitic material in individual animals, depending on their age, the rate and duration of infection and their innate ability to develop resistance to the parasite.

Type
Research Article
Information
Parasitology , Volume 69 , Issue 3 , December 1974 , pp. 315 - 327
Copyright
Copyright © Cambridge University Press 1974

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

Chiejina, S. N. (1972). Studies on the population kinetics and pathology of experimental Trichostrongylus colubriformis (Giles, 1892) infections in lambs. Ph.D. Thesis. University of Edinburgh.Google Scholar
Chiejina, S. N. & Sewell, M. M. H. (1974). Experimental infections with Trichostrongylus colubriformis (Giles, 1892) in lambs: worm burdens, growth rate and host resistance resulting from prolonged escalating infections. Parasitology 69, 301–14.CrossRefGoogle ScholarPubMed
Christie, M. G., Brambell, M. R. & Charleston, W. A. G. (1964). Worm populations in young sheep dosed daily with 10000 larvae of Haemonchus contortus. Journal of Comparative Pathology and Therapeutics 74, 435–46.CrossRefGoogle Scholar
Crofton, H. D. (1955). Nematode parasite populations in sheep on Lowland farms. Technical communication No. 35, Commonwealth Bureau of Helminthology, St Albans, Bucks., England.Google Scholar
Dineen, J. K. (1963). Immunological aspects of parasitism. Nature, London 197, 268–9.CrossRefGoogle ScholarPubMed
Donald, A. D., Dineen, J. K., Turner, J. H. & Wagland, N. M. (1964). The dynamics of the host-parasite relationship. 1. Nematodirus spathiger in sheep. Parasitology 54, 527–44.CrossRefGoogle Scholar
Gibson, T. E. & Parfitt, J. W. (1972). The effect of age on the development by sheep of resistance to Trichostrongylus colubriformis. Research in Veterinary Science 13, 529–35.CrossRefGoogle ScholarPubMed
Gibson, T. E. & Parfitt, J. W. (1973). The development of resistance to Trichostrongylus colubriformis by lambs under conditions of continuous infection. Research in Veterinary Science 15, 220–3.CrossRefGoogle ScholarPubMed
Gordon, H. McL. (1948). The epidemiology of parasitic diseases with special reference to studies with nematode parasites of sheep. Australian Veterinary Journal 24, 17–45.CrossRefGoogle Scholar
McCoy, O. R. (1931). Immunity reactions of the dog against hookworm (Ancylostoma caninum) under conditions of repeated infection. American Journal of Hygiene 14, 268–303.Google Scholar
Michel, J. F. (1963). The phenomena of host resistance and the course of Ostertagia ostertagi in calves. Parasitology 53, 63–84.CrossRefGoogle Scholar
Michel, J. F. (1967). Regulation of egg output of populations of Ostertagia ostertagi. Nature, London 215, 1001–2.CrossRefGoogle ScholarPubMed
Michel, J. F. (1969). Some observations on the worm burdens of calves infected daily with Ostertagia ostertagi. Parasitology 59, 575–95.CrossRefGoogle ScholarPubMed
Michel, J. F. & Ollerenshaw, C. B. (1963). ‘Parasitic gastro-enteritis’. In Animal Health, Production and Pasture (ed. Worden, A. N., Sellers, K. C. and Tribe, D. E.), pp. 479–505. London: Longmans.Google Scholar
Michel, J. F. & Sinclair, I. J. (1969). The effect of cortisone on the worm burdens of calves infected daily with Ostertagia ostertagi. Parasitology 59, 691–708.CrossRefGoogle ScholarPubMed
Morgan, D. O., Parnell, I. W. & Rayski, C. (1951). The seasonal variations in the worm burden of Scottish hill sheep. Journal of Helminthology 25, 177–212.CrossRefGoogle Scholar
Mulligan, W., Urquhart, G. M., Jennings, F. W. & Neilson, J. T. M. (1965). Immunological studies on Nippostrongylus brasiliensis infection in the rat: the ‘self-cure’ phenomenon. Experimental Parasitology 16, 341–7.CrossRefGoogle ScholarPubMed
Pradham, S. L. & Johnstone, I. L. (1972). Haemonchus contortus – the effect on lambs of prolonged exposure to daily and weekly doses of infective larvae. Parasitology 64, 143–52.CrossRefGoogle Scholar
Stewart, T. B. (1958). Resistance of cattle to infection with Cooperia punctata. Proceedings of the Helminthological Society of Washington 25, 131–2.Google Scholar
Stewart, D. F. & Gordon, H. McL. (1958). Immune reactions to Trichostrongylus colubriformis infection in sheep. Nature, London 181, 921.CrossRefGoogle ScholarPubMed
Stoll, N. R. (1928). The occurrence of self-cure and protection in typical nematode parasitism. Journal of Parasitology 15, 147–8.Google Scholar
Stoll, N. R. (1929). Studies with the strongyloid nematode Haemonchus contortus. 1. Acquired resistance of hosts under natural reinfection conditions outdoors. American Journal of Hygiene 10, 384–418.Google Scholar
Tetley, J. H. (1941). The epidemiology of low-plane nematode infection in sheep in Mana-watu district, New Zealand. Cornell Veterinarian 31, 243–65.Google Scholar
Tetley, J. H. (1949). Rhythms in nematode parasitism of sheep. Department of Scientific and Industrial Research, Wellington, New Zealand. Bulletin No. 96.Google Scholar