A comparative pathological study of three strains of Trypanosoma cruzi in an experimental model

Abstract

Trypanosoma cruzi. the etiological agent of Chaps' cliscase. shows a wide variation in its biological hcl ia\ . io~~dre pending on the geographical distribution of different strains. Moreover. sonic. strains can show; variations with the course of tinic. We have studied the tissular tropism of three strains of T. cruzi, Cali. Buli\,ia and Y. from different geographical origins (Colombia. Bolivia ancl I3rasil respectively) on Swiss inice in order to detect any pnrsihle modification in their behaviour attributable only to parasite but not to host variations. The anatoniopathological stud!! of sections from heart. brain. liver. spleen. lymphatic ganglion. skeletal muscle and colon from Swiss mice infected with these strains has cvidencecl the presence of some important tliscrcpancics hctwecn the tissular tropism expected from thcir former clescriptions. and classical typification and then observed lesions. The greatest variations were found in the Y strain which had been described as eniincntly I-eticulotropic but presented lesions in all the organs except tlie spleen and lymphatic ganglion. We consider that the x~ariationsf ound in our study can only be explained in ternis of changes in the properties of the strains consiclercd. and conclude that the classic typificrrtion techniques based on the constant! of the characteristics of the parasite are not fully reliable for the description and clinical management of some evolving strains.