Experimental Studies and Critical Considerations Regarding the Life Cycle of Trypanosoma Cruzi

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  • Bacteriological Laboratory of the Children's Hospital, University of Cordoba, Argentina

In the life cycle of Trypanosoma cruzi, the causative agent of Chagas' disease, as described in most publications, the organism after an incubation period enters the blood-stream of the vertebrate host as a narrow, active “metacyclic” trypanosome, that develops without multiplication into a broad “blood form.” When deposited in the tissues, it becomes a round leishmanian type that undergoes multiplication and eventually produces cyst-like accumulations. Some of the leishmanian forms may revert to trypanosomes and reinfect the blood, thus producing new metastatic foci. Since it is difficult to follow the transformation process within mammalian tissues, the developmental stages have been studied chiefly in artificial cultures and in the invertebrate host, Triatoma, where multiplication also begins with the leishmanian form. According to the accepted belief the life cycle of T. cruzi in the vertebrate and invertebrate hosts and in cultures takes the following identical course with no sexual process involved.