The Milroy lectures on kala-azar, delivered before the Royal College of Physicians of London. Lecture III, The life-history of the parasite, mode of infection, and prophylaxis / by Leonard Rogers.
- Leonard Rogers
- Date:
- 1907
Licence: Public Domain Mark
Credit: The Milroy lectures on kala-azar, delivered before the Royal College of Physicians of London. Lecture III, The life-history of the parasite, mode of infection, and prophylaxis / by Leonard Rogers. Source: Wellcome Collection.
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![pore Se a ae Le as sinin deeply and are easy tocount. The total result is very dective. Adult Parasites.—When segments are stained in this way the internal structures, particularly the reproductive organs and tbe ova, are well brought out. It is best to allow the psrasites or the segments to remain in the acid solution for «bout one hour, and in the eosin solution overa night. After thorough drying with absorbent paper they are cleared in clove oil or xyiol for twenty-four bours and then mounted in balsam. Spores.—My colleague, Dr. J. A. Nixon, working with eertain fungi of the skin and hair, informs me that he finds this device gives very satisfactory results with those spores which sre only stained with difficulty by the methods usually employed for this purpose. Ghe Milroy Lertures | KADLA-AZARS DELIVERED BEFORE THE RoyAL COLLEGE OF PHYSICIANS of LONDON. Br LEONARD ROGERS, M.D., F.R.C.P., LM.S., PROFESSOR OF PATHOLOGY, CALCUTTA. Lecture III. THE LIFE-HISTORY OF THE PARASITE, MODE OF INFECTION, AND PROPHYLAXIS. [ABSTRACT. ] ul HAVE now dealt with kala-azar both collectively as an epidemic and individually as a disease, but have still to discuss the evidence I obtained in Assam regarding its infectiousness before describing the life-history of the parasite which producesit. — _ When I went to Assam in 1896 there was much differ- ence of opinion as to whether kala-azar was infectious or not, the majority holding that as it was certainly malarial it therefore could not be infectious, while a few contended that it was certainly a communicable disease, and there- cre it could not be simply malarial in nature, but no one had found time to inquire into the exact way in which it spread. In order to settle this important point I travelled over 150 miles on foot from village to village, and obtained the histories of the introduction of the disease into them from the head men, who return all the deaths, and who were always able to give me detailed information on the subject. Very similar stories were constantly related to the effect that some one suffering from the disease had come to live in the village, usually with relatives, and then others, who resided in the same house, were shortly afterwards attacked, and on the survivors of the first infected household being taken into. other families they in turn suffered, while after a year or two the disease became widespread, and frequently from one to two thirds of the people eventually died of it before it began to decrease. Wherever the infection had spread a similar kind of history was obtained, while whenever a village had escaped, although surrounded by infected ones, it was found that for some reason or other they had no communication with each other, even if only a few hundred yards apart. Thus a small village of Brahmins, who had no intercourse with the infected low caste people around them, escaped, although all the sur- tounding villages had been attacked for several years. Again, one part of a Village, which was separated from the rest by only a few small rice-fields, remained free for years owing to their head man not allowing them to have any intercourse, even with their relations in the infected portion. On the other hand, on visiting a village which was reported to be infected, although all those around it were free, I found that it belonged to people who had recently moved there from a badly-infected part of tue district, bringing the disease with them. ‘The extreme steps which the people themselves sometimes took to prevent the spread of the disease is also strong evidence of its infectiousnegs in their eyes, For example, a girl, ‘who had married a man ina healthy village, but soon after was found to be suffering from kala-azar, was turned out, while her own father, in a neighbouring uninfected village, was prevented from taking her into his house, eo she Was living in a hut erected in the open rice- fields at the time of my visit. isolating cases of the disease was adopted by the Garos, who are reported to have gone so far as to render the patients comatose with drink and then burn them in their huts. All the evidence goes to show that the infection is, as a rule, obtained by sleeping in a house with infected persons for a longer or shorter time, in some cases only for a day or two. Moreover, the plan of moving the village to a new site appeared to have a distinctly good effect in lessening the disease when occasionally resorted to by the people themselves, so that I thought the infection might possibly pass through the soil. It was on the knowledge of the infection being largely a house one that I based the prophylactic measures which proved £0 successful long before the parasite of kala-azar was discovered, but now that we possess much more definite information regarding the true pathology of the disease it will be best to describe the life-history of the protozoal organism of kala-azar before taking up the important practical question of prophylaxis, as the latter will thus be rendered more definite. THE PARASITE OF KALA-AZAR AND ITS DISTRIBUTION IN THE Human Bopy. The parasite of kala-azar was independently found by more than one observer, but to W. B. Leishman, R.A.M.C., belongs the credit of having had the courage to first probably a degenerate stage of a.human trypanosome, not, very long after that organism had been found in a fever in Africa by the late Dr. Dutton, while Rose Bradford and Plimmer had previously described a form of the Trypanosoma brucei similar to the bodies Leishman found. As soon as Leishman’s paper reached India, C. Donovan, I.M.S., recorded that he had independently observed the same bodies in the spleens of patients dying of prolonged fever in Madras one month before Leishman’s note was pub- lished, and as he was alsoable to find them in fresh spleen blood obtained by puncture of the organ during life, he was able to disprove Leishman’s suggestion that they were degenerate trypanosomes, for the flagellate form of the organism has never been found in the human system. Laveran and Mesnil, after examining specimens sent by Donovan, concluded that the organism was a piroplasma, while J. H. Wright of Boston, at the end of 1903, de- scribed similar bodies to those of Leishman and Donovan in a form of chronic ulceration met with in the Punjab known as Delhi boil, in which D. D. Cunningham had, as early as 1885, described the aggregations of these peculiar bodies. As kala-azar is unknown in the Punjab there is good reason to believe that the parasite of Delhi boil is quite a distinct species from that of the Assam fever. Tn 1896 I had stained smears of kala-azar spleens with aniline dyes without being able to distinguish these bodies, which are not well shown by them, while Romenowsky’s stain and its numerous modifications had not then come into common use, and I mainly used fresh unstained blood films, as then advised by Sir Patrick Manson and others, for searching for malarial or other protozoal parasites. The papers just referred to appeared while 1 was on leave in England, and I quickly realized, as was also suggested by Donovan, Ross, and others, that if many of the cases previously known as “ malarial cachexia” were really caused by the new parasites, then kala-azar of Assam must be also produced by it, for I had shown in my report that the Assam outbreak was but an epidemic form of the so-called “ malarial cachexia.” On returning to India at the end of 1903 I obtained some slides of spleen blood of kala-azar patients from my friend, Dr. Dodds Price, and readily found the new parasites in them, as well as in several cases of chronic spleen fever in the Dinajpur district, which were evidently the sporadic form of the same disease. At about the same time Dr. Bentley independently found the same parasites in kala-azar cases, and published his observations shortly before my own appeared in print. Other cases in Dinajpur with large spleens following chronic fever showed only malarial parasites in their spleen blood; and I found it impossible at a single examination to differentiate between the two forms clinically, although subse- quently able to do so by: the blood changes, as described in my last lecture. It is not, therefore, surprising that kala-azar has been so long confounded with chronic forms of malarial fever; and the discovery of the new parasite](https://iiif.wellcomecollection.org/image/b33450249_0005.jp2/full/800%2C/0/default.jpg)
