title: A DTU-dependent blood parasitism and a DTU-independent tissue parasitism during mixed infection of Trypanosoma cruzi in immunosuppressed mice.
abstract: Trypanosoma cruzi (Tc) diversity is determined by different biological, genetic, and biochemical markers and has been grouped into six discrete typing units (DTUs) or taxonomic groups (TcI-TcVI). This variability, coupled with natural reinfection or the hosts' immunosuppression, may play an important role in the pathogenesis of Chagas disease. Therefore, we evaluated the blood and tissue parasitism and genetic profile of mice coinfected with the TcII (JG) strain and TcI AQ1-7 (AQ) or MUTUM (MT) strains during the acute and chronic phases of the disease and during immunosuppression. T. cruzi blood populations in mixed infections were clearly associated with the TcII strain during acute and chronic phases or during immunosuppression. However, in tissues, the parasite populations were distributed according to the strain and the stage of infection. TcII populations overlapped TcI strains during the acute phase; in contrast, during chronic phase, both TcI strains were more prevalent than the TcII strain. The immunosuppression induced selective exacerbation of parasite populations, leading to reactivation of the TcII strain when associated with the AQ, but not with MT strain. Thus, a differential distribution of T. cruzi populations in blood and tissues with overlapping according to the stage of infection and strain used was observed. Blood parasitism was associated with the DTU TcII and tissue parasitism with a specific parasite strain and not with DTUs. Finally, to our knowledge, this is the first study to analyze subpatent blood parasitism and to simultaneously identify different T. cruzi populations in tissues and blood.
authors.affiliation: Pós Graduação em Ciências Fisiológicas, Universidade Federal do Triângulo Mineiro, Uberaba, Minas Gerais, Brazil, tonsales@fcfrp.usp.br.
authors.forename: Helioswilton
authors.initials: H
authors.lastname: Sales-Campos
authors.forename: Henrique Borges
authors.initials: HB
authors.lastname: Kappel
authors.forename: Cristiane Pontes
authors.initials: CP
authors.lastname: Andrade
authors.forename: Tiago Pereira
authors.initials: TP
authors.lastname: Lima
authors.forename: Mardén Estevão
authors.initials: ME
authors.lastname: Mattos
authors.forename: Alessandra
authors.initials: A
authors.lastname: de Castilho
authors.forename: Dalmo
authors.initials: D
authors.lastname: Correia
authors.forename: Luis Eduardo Ramirez
authors.initials: LE
authors.lastname: Giraldo
authors.forename: Eliane
authors.initials: E
authors.lastname: Lages-Silva
mesh_terms: D000818:Animals; D014355:Chagas Disease / Q000097:blood* / Q000469:parasitology* / Q000473:pathology; D060085:Coinfection / Q000469:parasitology*; D007165:Immunosuppression Therapy; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D014349:Trypanosoma cruzi / Q000145:classification* / Q000235:genetics