Differentiation and Multiplication of Dyskinetoplastic Trypanosoma cruzi in Tissue Culture and in the Mammalian Host*

SYNOPSIS. In cultures of the Y strain of Trypanosoma cruzi treated with acriflavine, a very high proportion of the crithidiae may be dyskinetoplastic. These crithidiae cannot be maintained in subcultures but are able to differentiate into (dyskinetoplastic) metatrypanosomes. In tissue cultures infected with these metatrypanosomes, or with blood trypanosomes and treated with acriflavine, dyskinetoplastic T. cruzi is able to go thru the whole sequence of stages that characterizes its cycle in the vertebrate host: penetration by trypanosomes into cells, differentiation into leishmaniae, multiplication in this phase and differentiation again into trypanosomes. The same may occur in the mammalian host itself. The physiological implications of these findings are discussed and special attention is called to polymorphism of blood forms of T. cruzi, which probably has the same significance it has in the brucei‐evansi group of trypanosomes.