Experiments with Trichostrongylus colubriformis (Giles, 1892) in the guinea-pig I. The effect of the host response on the distribution of the parasites in the gut

Abstract

The distribution of Trichostrongylus colubriformis in the intestine of the non-immune guinea-pig is described. At day 10 of the primary infection the majority of larvae were found in the anterior half of the small intestine with progressively smaller numbers in all parts of the gut posterior to this. However, soon after day 10 a migration of the worm population took place so that by day 15, before there had been a reduction in the total present, the majority of worms were found in the posterior small intestine. Thereafter the posterior movement continued, but while the numbers in the large intestine increased the movement then coincided with the beginning of the expulsion of the worms.By the irradiation of guinea-pigs prior to infection the posterior migration was prevented, indicating that the latter was the result of a host response.The independent migration of two generations of parasites was noted and two possible explanations are put forward.This work was carried out during the tenure of a Research Training Scholarship awarded by the Animal Health Trust.The author would like to thank Professor W. I. B. Beveridge in whose Department this work was carried out, and also Mr King of the Department of Radio-therapeutics, University of Cambridge, who irradiated the guinea-pigs used in Expt. 3.