Comparison of the effects of infection with Trichostrongylus colubriformis, T. vitrinus and T. rugatus in merino lambs.

Groups of six worm-free merino lambs were infected with 100,000 larvae of T. colubriformis, T. vitrinus, T. rugatus or a mixture of the three species and were slaughtered 21 days later. Nematodes were distributed predominantly in the first 3 m of the small intestine where they caused subtotal villus atrophy. T. vitrinus caused severe erosion of the epithelium; erosion was less severe with T. colubriformis infections and mild with T. rugatus infections. Plasma concentrations of albumin declined during the experiment and were most marked in sheep infected with T. vitrinus. Plasma phosphate concentrations declined during infection with all three species, while plasma concentrations of globulin and calcium declined only in sheep infected with T. vitrinus. Food intake was reduced in all groups, but was most marked with sheep infected with T. vitrinus. T. vitrinus appeared to be more pathogenic than the other species.

[1]  R. L. Coop,et al.  Chronic infection with Trichostrongylus vitrinus in sheep. Some effects on food utilisation, skeletal growth and certain serum constituents. , 1979, Research in veterinary science.

[2]  L. Symons,et al.  Anorexia: occurrence, pathophysiology, and possible causes in parasitic infections. , 1985, Advances in parasitology.

[3]  P. Dewey,et al.  Calcium and phosphorus absorption in lambs exposed to Trichostrongylus colubriformis. , 1985, Journal of comparative pathology.

[4]  I. Barker.  Location and distribution of Trichostrongylus colubriformis in the small intestine of sheep during the prepatent period, and the development of villus atrophy. , 1975, Journal of comparative pathology.

[5]  D. Pout.  The mucosal surface patterns of the small intestine of grazing labms. , 1970, The British veterinary journal.

[6]  I. Barker,et al.  Morphogenesis of Trichostrongylus rugatus and distribution during development in sheep. , 1983, Veterinary parasitology.

[7]  R. Martin,et al.  Mortality in weaner sheep in South Australia under different regimes of anthelmintic treatment , 1985 .

[8]  I. Barker.  The relationship of abnormal mucosal microtopography with distribution of Trichostrongylus colubriformis in the small intestines of lambs. , 1974, International journal for parasitology.

[9]  S. Taylor,et al.  Trichostrongylus vitrinus: The influence of age of sheep and population size on the intestinal distribution , 1980, Journal of Helminthology.

[10]  F. Jackson,et al.  Development of morphological changes in the small intestine of lambs continuously infected with Trichostrongylus vitrinus. , 1983, Research in veterinary science.

[11]  I. Horak,et al.  The pathological physiology of helminth infestations. 3. Trichostrongylus colubriformis. , 1968, The Onderstepoort journal of veterinary research.

[12]  G. Pearson,et al.  Trichostrongylus vitrinus in sheep. I. The location of nematodes during parasitic development and associated pathological changes in the small intestine. , 1979, Journal of comparative pathology.

[13]  T. Gibson,et al.  The development of resistance to Trichostrongylus colubriformis by lambs under conditions of continuous infection. , 1973, Research in veterinary science.

[14]  I. Barker,et al.  Intestinal pathology associated with Trichostrongylus colubriformis infection in sheep: vascular permeability and ultrastructure of the mucosa , 1975, Parasitology.

[15]  I. Barker.  A study of the pathogenesis of Trichostrongylus colubriformis infection in lambs with observations on the contribution of gastrointestinal plasma loss. , 1973, International journal for parasitology.

[16]  R. L. Coop,et al.  Subclinical trichostrongylosis in growing lambs produced by continuous larval dosing. The effect on performance and certain plasma constituents. , 1976, Research in veterinary science.

[17]  I. Barker,et al.  Intestinal pathology associated with Trichostrongylus colubriformis infection in sheep: histology , 1975, Parasitology.

[18]  G. Pearson,et al.  Trichostrongylus vitrinus in sheep. II. The location of nematodes and associated pathological changes in the small intestine during clinical infection. , 1979, Journal of comparative pathology.