Trypanosomes and trypanosomiasis / by A. Laveran and F. Mesnil. : Translated and much enlarged by David Nabarro.

  • Charles Louis Alphonse Laveran
Date:
1907
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Licence: In copyright

Credit: Trypanosomes and trypanosomiasis / by A. Laveran and F. Mesnil. : Translated and much enlarged by David Nabarro. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    morphological characters in the blood of different species of animals. It follows, therefore, that it may often be difficult to identify a trypanosome, and on that account several of these hsematozoa still lack identification. Some observers have maintained that the names surra and nagana referred to the same disease, while others have sought to identify mal de caderas with surra. On the other hand, it was believed for some time that the trypanosome found in the blood of man in Gambia was different from that found in Uganda in the cerebro- spinal fluid of sleeping sickness patients. At the present day there is a little uncertainty about the nature of several African trypanosomes —notably that of the epizootic disease amongst dromedaries in Tim- buctoo, which has been described under the name mbori} To identify a trypanosomiasis one must take into consideration: (1) the morphological and biological characters of the trypanosomes ; (2) the symptoms of the disease as it occurs naturally; (3) the pathogenic action on different mammals; and (4) the action of the particular trypanosome upon animals immune against allied species of trypanosome. In this way we have succeeded in showing that nagana, surra, and mal de caderas are three distinct morbid entities; that the trypanosomiasis of horses in Gambia has nothing in common with the human disease; and, lastly, that the Trypano- soma gambiense and Trypanosoma icgandense should be regarded as identical. Nocard and Lignieres have shown in the same way that dourine is distinct from nagana and from mal de caderas. In certain trypanosomiases and amongst certain species of animals the parasites are very scanty in the blood and body fluids, a fact which greatly increases the difficulties of investigation. In animals with dourine it is rare to find trypanosomes in the blood, whereas they are met with in large numbers in the oedema fluids. In sleeping sickness it is often necessary, in order to demonstrate the presence of trypanosomes, to centrifuge the blood or the cerebro- spinal fluid obtained by lumbar puncture. The paucity of the parasites in the blood does not preclude their pathogenic action. In addition to dourine and human trypano- somiasis, animals may succumb to other trypanosomiases even when the parasites are very scanty in their blood. In this respect there are great differences amongst mammals. The trypanosomes of surra, nagana, and mal de caderas swarm in the blood of infected rats, mice, and dogs, whilst they are scanty, or very scanty, in the blood ot infected rabbits, goats, sheep, and cattle. Although the trypanosomes appear to multiply with difficulty in these animals, the infection is none the less serious. Surra, nagana, and mal de caderas always cause death in rabbits. 1 [It has recently been shown by Laveran that wdon is merely a variety of surra. See Chapter VI.]
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