Publisher Summary Chagas' disease-like all really great and important discoveries-has its own and very peculiar history, called by Magalhaes , a “tragicomedy, which embittered and destroyed the life of one of our greatest compatriots”. In this history it is useful to distinguish the following six periods. Chagas in 1908 discovered in the intestine of the blood-sucking triatomas that were common in the primitive huts of the Brazilian hinterland, an unknown trypanosome, which was named by “Schizotrypanum cruzi.” The presence of this parasite in bugs suggested to him the possible existence of an infectious disease in animals and man. Soon afterwards Chagas also found the parasites in the blood of domestic animals (dogs and cats) and in the blood of a sick child with a high temperature. The discovery of American trypanosomiasis by Carlos Chagas represents one of the most fascinating events in the history of medicine. It is almost incredible that such severe pathological manifestations, which represent the “causa mortis” of one third of our autopsy material, would have been overlooked or unknown before Chagas' unique discovery. American trypanosomiasis shows a very peculiar pathology of homeostasis of the human organism, and represents even today a new realm in pathology, which becomes understandable through Cannon's law of denervation.

Chagas' disease and Chagas' syndromes: the pathology of American trypanosomiasis.

Publisher Summary Among the protozoa of the Trypanosomatidae family, a large number of species represent agents of diseases, such as Chagas' disease. This chapter reviews some aspects of the cell biology of Trypanosoma cruzi, giving emphasis to those aspects related to the ultrastructure of pathogenic protozoa. Protozoa of the Trypanosomatidae family show, during their, life cycle, several forms which can be easily identified by light microscopy in Giemsa-stained preparations. The chapter also explains the life cycle of T. cruzi. In the life cycle of T. cruzi, there are forms which are able to divide. There is one form, considered to be highly differentiated and responsible for the infectivity of these protozoa, which does not divide. It is highlighted that the trypomastigote form can transform into a rounded form which possesses a free flagellum. This form, which appears in the stomach, is able to transform into either short epimastigotes that start a process of multiplication in the intestinum or into long epimastigotes which move to the more posterior region of the digestive tract of the bug. Cell surface is also emphasized in the chapter.

Cell Biology of Trypanosoma cruzi

Trypanosoma cruzi: characterization of an intracellular epimastigote-like form.

Avian embryos and tissue culture in the study of parasitic protozoa. II. Protozoa other than Plasmodium.

Mouse peritoneal macrophage cells suspended in a TC 199 calf serum medium and cultured in Leighton tubes, were infected with Trypanosoma (Schizotrypanum) cruzi culture forms in order to study the development of this parasite in vitro. Three cycles of development were thought to occur:
 1. Epimastigotes or trypomastigotes were taken up by macrophages and transformed into amastigotes. These multiplied by binary fission and ruptured the infected cell after 4‐5 days. Released amastigotes were taken up by uninfected macrophages and the cycle was repeated.
 2. A small proportion of intracellular amastigotes developed into ‘ovoid forms’ which transformed progressively into promastigotes, epimastigotes and trypomastigotes.
 3. Some amastigotes became ‘round forms’ from which sphaeromastigotes developed. These transformed directly into trypomastigotes without the formation of epimastigotes.

Developmental cycles of Trypanosoma (Schizotrypanum) cruzi (Chagas, 1909) in mouse peritoneal macrophages in vitro.

Chick embryo tissue cultures were smeared with Schizotrypanum from different sources. The cultures were inoculated with flagellates from blood-agar cultures and in one instance from blood of an infected guinea-pig. Carrels technique of tissue culture, with slight modifications, was employed. The tissue used were spleen, myocardium, liver, epithelium of the iris, spinal ganglion and monocytes from chicken blood. In all these tissues the flagellate developed easily, parasitizing different types of cells: fibroblasts, histiocytes, macrophages, epithelial cells, cells of the nervous system, etc. The authors were able to follow the complete cycle of the parasite, observing its classic evolution: transformation into leishmania, multiplication by binary division, transformation into crithidia and finally into trypanosome. They also observed forms of the parasite which possibly developed directly from leishmania to trypanosome without apparently going through the crithidia stage. They succeeded in infecting a white mouse with a human strain of S. cruzi after passage through tissue culture. The authors also pointed out different phenomena observed in the relations between the cells and the parasites.

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H. Meyer

Papers

Estudo do ciclo evolutivo do "Schizotrypanum Cruzi" em cultura de tecidos de embrião de galinha