Immunological Identification of Trypanosoma cruzi Lineages in Human Infection Along the Endemic Area

Genotyping studies show a polarized geographic distribution of Trypanosoma cruzi lineages in humans Here, we assessed their distribution along Latin America through an immunological approach we designated Western blot (WB) assay with Trypomastigote small-surface antigen (TSSA) I and TSSA IT (TSSA-WB) These antigens are expressed by T cruzi I (TCI, now Tcl) and T cruzi II (TCII, reclassified as Tell to TcVI) parasites TSSA WB showed good concordance with genotyping tests An unexpected frequency of TSSA IT recognition was observed in Colombia Venezuela, and Mexico (northern region of Latin America) In Argentina and Paraguay (southern region), immunophenotyping confirmed the already reported TCII (TcII to TcVI) dominance The lineage distribution between these regions showed significant difference but not among countries within them (except for Colombia and Venezuela) TSSA WB shows TCII emergence in the northern region where TCI was reported as dominant or even as the unique T cruzi lineage infecting humans