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On the Localization of Adult Trichinae in the Intestine

1938; American Society of Parasitologists; Volume: 24; Issue: 3 Linguagem: Inglês

10.2307/3272292

1937-2345

Hans Roth,

Genetics, Aging, and Longevity in Model Organisms

That Trichinella spiralis in its adult stage prefers certain parts of the intestine is a question to which but little attention has been paid. Writers on this form mention only that trichinae inhabit the small intestine. According to McCoy (1931), who examined the small intestines of rats for trichinae, it is recognized that a few trichinae are sometimes found in the cecum; but, on account of the practical difficulty of examining these parts, which are full of foreign material, he did not include the cecum and large intestine in his investigations. While investigating the immunity of guinea pigs to super-infection with Trichinella spiralis (to be published), I tried to find a reliable method of counting the number of adult trichinae in the intestine. In contrast to McCoy who counted the total number of worms by stripping the mucosa from the whole intestine, dissolving it in 0.04 per cent sodium hydroxide, and then testing 1 cc samples of the solution, I tried, so far as possible, to determine the number of the adult trichinae in situ. My procedure was, to cut the different sections of the intestine into small pieces, which were then measured. The mucosa on each piece, with the covering layer of feces, was then stripped off, put on a very large slide and pulled to pieces in 0.9 per cent saline solution by means of needles. The slide was carefully examined several times under a binocular microscope and the worms collected. This method was, of course, very tedious and took a great deal of time, but the results attained by complete, or nearly complete, examination of only a few intestines showed a distinctly localized distribution of the trichinae. It was therefore possible, during the further investigations, to examine a series of samples from different sections of the intestine (as described below), as these samples give a clear idea of the relative extent of the inffection. The length of the total samples taken from the small intestine of each animal was about 25 cm; from the cecum about 20 sq cm. No samples were taken, as a rule, from the large intestine. All the guinea pigs in my experiments were infected by the ingestion of larvae, the numbers of which were exactly counted under the dissecting microscope, after having been freed from their cysts by artificial digestion in a manner similar to that described by McCoy. Altogether, more than fifty intestines have been examined, most of them by sampling, as described. Nearly all the animals revealed typical Received for publication, September 25, 1937. * From the Institute for General Pathology, University of Copenhagen. Director: Professor Oluf Thomsen, M.D.