Introduction: Genetic differences between T. cruzi I and T. cruzi ll may determine differences in their tissue tropism in the vertebrate host and may also be responsible for the differences in clinical manifestations of Chagas disease.
Objective: Two Colombian clones of the T. cruzi groups I and II were characterized biologically and genetically in a murine model.
Materials and methods: Strains Cas15 and AF1 belonging to the T. cruzi groups I and II were cloned in semisolid medium. A clone of each strain and a mix of both were used to infect mice; the mice were subsequently sacrificed at selected post-infection intervals. In order to identify the parasite presence in blood and organs, two methods were used (a) microhematocrit and (b) polymerase chain reaction with primers for satellite DNA and the intergenic region of miniexon.
Results: The T. cruzi I clone was more infectious, with a preferential tropism observed in heart, rectum and skeletal muscle, whereas clone T. cruzi II exhibited a preferential tropism for spleen and liver. During the infection with the clone mixture a predominance of the T. cruzi I clone over clone II in blood as well as in organs was observed.
Conclusions: The results corroborate that the genetic differences between the T. cruzi groups correlate with their tissue tropism, and can play an essential role in explaining the clinical manifestations of Chagas disease observed in Colombia.