Trypanosoma cruzi belongs to order Kinetoplatida, which includes the families Bodonidae Hollande, 1952 and Trypanosomatidae Kent, 1880. Genus Trypanosoma is one of the most important within the Trypanosomatidae family, as it includes a series of species that cause relevant human diseases, such as Trypanosoma cruzi, the agent of Chagas disease.
Optical microscopy allows us to identify, in the parasite: (i) the general shape of its cell, (ii) its nucleus, (iii) kinetoplsat, and (iv) the flagellum. According to: (i) the general form of the evolutionary form; (ii) the relative position between the flagellum and the nucleus; (iii) the location of the flagellar pocket (from which the flagellum emerges); and (iv) location of the free flagellum, it is possible to identify the different evolutionary forms of trypanosomatidae: amastigote, tripomastigote, and epimastigote. Cell culture methods make it possible to obtain a large number of these cells, resulting in morphological, structural, biochemical and genetic studies. Scanning electron microscopy studies have revealed the structural complexity of this parasite. Biochemical and genetic studies have highlighted the molecular diversity of T. cruzi and opened up the questioning on the possible relation between parasite diversity and the diversity of the clinical forms of Chagas disease.