Volume 1

On the possibility of the occurrence of trypanosomiasis in India / by W.B. Leishman.

  • Leishman, W. B. (William Boog), Sir, 1865-1926.
Date:
1903
Catalogue details

Licence: Public Domain Mark

Credit: On the possibility of the occurrence of trypanosomiasis in India / by W.B. Leishman. Source: Wellcome Collection.

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    sites can only rarely be found, and frequently the most care- ful search of several films fails to demonstrate a single trypanosoma, the organisms in this case being found in large numbers either in some of the internal organs and the bone marrow, or forming accumulations in the lymphatics of cer- tain regions, such as the eye or the genital organs. It is thus evident that a fatal attack of trypanosomiasis in an animal does not necessarily postulate the occurrence of the parasites in the peripheral blood, in numbers large enough to permit of microscopical detection. Again, the chronic nature of the disease in the few recorded eases of trypanosomiasis in man and the immunity which man appears to possess to infection by other varieties of trypano- soma, such as nagana, surra, dourine, mal de eaderas, etc., would appear to show that man is very resistant to trypano- soma infection. It is not, then, I think, unreasonable to assume, first, that when trypanosomiasis does occur in man the parasites are more likely to multiply and accumulate in the capillaries or lymphatics of the internal organs than to invade the general circulation in large numbers; and, secondly, that the cases which have been recently reported are in reality exceptional cases, in which the resistance of the individual was compara- tively low, and in which the parasites were able tc develop and multiply in the blood stream, as they do in the case of a horse, rat, or mouse infected by trypanosoma brucei. It appears to me, therefore, as at least possible that trypano- somiasis may be a much commoner disease of tropical countries, including India, than is generally supposed, and that its non-recognition may be due, as I have suggested above, partly to the tendency of the parasite to confine itself to the internal organs during the life of its host, and partly to the rapid degeneration and loss of characteristic shape which follow on the death of the organism and render its identification, in sections or smear preparations, a matter of difficulty. This difficulty is further increased by reason of the fact that only by Romanowsky staining can the macro- nuclei and micro-nuclei be rendered visible, and then only in smear preparations, since it is very hard to produce satis- factory chromatin staining in sections owing to the chemical alterations induced in the tissues by the various processes of hardening and embedding. I have tried to modify these pro- cesses in various ways, bnt so far without success. With a view, then, to finding out whether some of these severe tropical cachexias, such as the Dum-dum fever, may not be due to trypanosomiasis, I would suggest that, as a routine practice, necropsies of such cases should include the staining of smear preparations from the spleen, lungs, and liver by Romanowsky’s method, and a careful seareh for the degeneration forms of the parasites which I have described. Increased facilities for the detection of trypanosomiasis during life are much to be desired. Positive results might be obtained by inoculation of a susceptible animal with blood from a suspected case, although this procedure does not appear to have been successful in Dr. Manson’s case, and Drs. Annett and Dutton record that the pathogenicity of the trypanosoma in their case was not marked in white rats. Possibly the monkey might prove more susceptible to the trypanosoma of man. Some of the methods of staining thick blood films by dissolving out the haemoglobin, such as those
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