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Field experiments on the Immunity of Lambs to Parasitic Gastritis caused by a mixed infection of Trichostrongylid Nematodes

Published online by Cambridge University Press:  05 June 2009

E. L. Taylor
E. L. Taylor
Affiliation:
(Veterinary Laboratory, Ministry of Agriculture.)
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Extract

Four lambs introduced to infective pasture early in life acquired an immunity to parasitic gastritis, the immunity being sufficiently strong to maintain them in good health under conditions of repeated reinfestation, heavy enough to lead to the death of ten lambs of a like age, but not so protected, within periods varying from weeks to weeks. At post-mortem examination the protected lambs were found to carry more worms than many of the lambs which died, although they had been observed to disseminate only one-thirteenth the number of eggs of some of those fatally affected. The infestation of individual lambs in the various groups showed marked differences, amounting in some instances to the presence of a large number of worms of one species in some lambs and the total absence of worms of that species from others.

The observations lead to the following conclusions:—

1. Lambs are able to acquire an immunity against parasitic gastritis powerful enough to protect them against a rate of reinfection at pasture that is sufficiently great to result in the death of unprotected lambs in less than seven weeks.

2. This immunity operates against the acquiring of infection, but also in enabling the lambs to resist the injurious effects of the infection. Resistant animals may carry more parasites than are carried at the time of death by non-resistant animals.

3. The immunity is acquired slowly and does not appear to become firmly established for 18 weeks. A gradually acquired infection leads to immunity while a quickly acquired infection leads to death where the final number of parasites is the same in both instances.

4. The immunity is specific and operates more powerfully on N. fillicolis and H. contortus than on Ostertagia, Trichostrongylus and Cooperia.

5. The immunity has an inhibitory influence on egg laying and on the development of young worms; the egg output of the worms may be reduced to one-thirteenth of the normal.

6. There are marked differences in the reactions of individual lambs, instances of marked resistance and of marked susceptibility having been observed.

7. The symptoms of parasitic gastritis are due to something more than the abstraction of blood by the worm.

8. The part of immunity which inhibits the production of eggs by the parasites develops earlier than the resistance to the harmful effects of the infestation.

Type
Research Article
Information
Journal of Helminthology , Volume 12 , Issue 3 , June 1934 , pp. 143 - 164
Copyright
Copyright © Cambridge University Press 1934

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References

Chandler, A. C., 1932a.—“Susceptibility and Resistance to Helminthic Infestation.” J. Parasit. xviii, 135–152. (W.L. 11428.)CrossRefGoogle Scholar
Chandler, A. C., 1932b.—“Experiments on Resistance of Rats to Superinfection with the Nematode Nippostrongylus muris.” Amer. J. Hyg. xvi, 750–782. (W.L. 600a.)Google Scholar
Fourie, P. J. J., 1931.—“The Haematology and Pathology of Haemonchosis in Sheep.” 17th Report of the Director of Veterinary Services and Animal Industry, Onderstepoort, Part 2 495–572.Google Scholar
Graybill, H. W., 1921.—“Data on the Development of Heterakis papillosa in the fowl.” J. Expt. Med. xxxiv, 259–270. (W.L. 11189.)CrossRefGoogle Scholar
Hill, R. B., 1926.—“The Estimation of the Number of Hookworms Harboured by the Use of the Dilution Egg-Count Method.” Amer. J. Hyg. vi, 19–41. (W.L. 600a.)Google Scholar
McCoy, O. R., 1931.—“Immunity Reactions of the Dog Against Hookworm (Ancylostoma caninum) under Conditions of Repeated Infection.” Amer. J. Hyg. xiv, 268–303. (W.L. 600a.)Google Scholar
Ross, I. C., 1932.—“Observations on the Resistance of Sheep to Infestation by the Stomach Worm (Haemonchus contortus).” J. Council for Sci. and Indust. Research, Australia, v, 73–80.Google Scholar
Sarles, M. P., 1929.—“The Effect of Age and Size of Infestation on the Egg Production of the Dog Hookworm Ancylostoma caninum.” Amer. J. Hyg. x, 658–666. (W.L. 600a.)Google Scholar
Sarles, 1932.—“Development of an Acquired Resistance in Rabbits by Repeated Infection with an Intestinal Nematode, Trichostrongylus calcaratus, Ransom 1911.” J. Parasit. xix, 61–82. (W.L. 11428.)CrossRefGoogle Scholar
Scott, J. A., 1928.—“An Experimental Study of the Development of Ancylostoma caninum in Normal and Abnormal Hosts.” Amer. J. Hyg. viii, 158–204. (W.L. 600a.)Google Scholar
Stoll, N. R., 1929.—“Studies with the Strongyloid Nematode Haemonchus contortus.” Amer. J. Hyg. x, 384–418. (W.L. 600a.)Google Scholar
Wells, H. S., 1931.—“Observations on the Blood Sucking Activities of the Hookworm, Ancylostoma caninum.” J. Parasit. xvii, 167–182. (W.L. 11428.)CrossRefGoogle Scholar
Winfield, G. F., 1933.—“Quantitative Experimental Studies on the Rat Nematode, Heterakis spumosa, Schneider, 1866.” Amer. J. Hyg. xvii, 168–228. (W.L. 600a.)Google Scholar