title: Comparative pathogenicity in Swiss mice of Trypanosoma cruzi IV from northern Brazil and Trypanosoma cruzi II from southern Brazil.
abstract: The geographical heterogeneity of Chagas disease (ChD) is mainly caused by genetic variability of the etiological agent Trypanosoma cruzi. Our hypothesis was that the pathogenicity for mice may vary with the genetic lineage (or Discrete Typing Unit - DTU) of the parasite. To test this hypothesis, parasitological and histopathological evaluations were performed in mice inoculated with strains belonging to the DTU T. cruzi IV (TcIV) from the State of Amazonas (northern Brazil), or the DTU T. cruzi II (TcII) from the State of Paraná (southern Brazil). Groups of 10 Swiss mice were inoculated with eight strains of TcIV obtained from acute cases (7) from two outbreaks of orally acquired ChD, and from the triatomine Rhodnius robustus (1) from Amazonas; and three strains of TcII obtained from chronic patients in Paraná. We evaluated the pre-patent period, patent period, maximum peak of parasitemia, day of maximum peak of parasitemia, area under the parasitemia curve, inflammatory process, and tissue parasitism in the acute phase. TcIV was less virulent than TcII, and showed significantly (p < 0.005) lower parasitemia levels. Although the levels of tissue parasitism did not differ statistically, mice infected with TcIV displayed significantly (p < 0.001) fewer inflammatory processes than mice infected with TcII. This supported the working hypothesis, since TcIV from Amazonas was less pathogenic than TcII from Paraná; and agreed with the lower severity of human cases of ChD in the Amazon region.
authors.affiliation: Post-Graduate Program in Health Sciences, State University of Maringá (UEM), Paraná, Brazil; Center for Medical and Pharmaceutical Sciences, State University of Western Paraná, Paraná, Brazil.
authors.forename: Sheila Karina Lüders
authors.initials: SK
authors.lastname: Meza
authors.affiliation: Department of Basic Health Sciences, UEM, Paraná, Brazil.
authors.forename: Edilson Nobuyoshi
authors.initials: EN
authors.lastname: Kaneshima
authors.affiliation: Department of Basic Health Sciences, UEM, Paraná, Brazil.
authors.forename: Sueli de Oliveira
authors.initials: Sde O
authors.lastname: Silva
authors.affiliation: Department of Basic Health Sciences, UEM, Paraná, Brazil.
authors.forename: Maristela
authors.initials: M
authors.lastname: Gabriel
authors.affiliation: Post-Graduate Program in Health Sciences, State University of Maringá (UEM), Paraná, Brazil; Department of Basic Health Sciences, UEM, Paraná, Brazil.
authors.forename: Silvana Marques
authors.initials: SM
authors.lastname: de Araújo
authors.affiliation: Post-Graduate Program in Health Sciences, State University of Maringá (UEM), Paraná, Brazil; Department of Basic Health Sciences, UEM, Paraná, Brazil.
authors.forename: Mônica Lúcia
authors.initials: ML
authors.lastname: Gomes
authors.affiliation: Department of Public Health, Federal University of Amazonas, Amazonas, Brazil.
authors.forename: Wuelton Marcelo
authors.initials: WM
authors.lastname: Monteiro
authors.affiliation: Post-Graduate Program in Tropical Medicine, State University of Amazonas, Dr. Heitor Vieira Dourado Tropical Medicine Foundation, Amazonas, Brazil.
authors.forename: Maria das Graças Vale
authors.initials: Md
authors.lastname: Barbosa
authors.affiliation: Post-Graduate Program in Health Sciences, State University of Maringá (UEM), Paraná, Brazil; Department of Basic Health Sciences, UEM, Paraná, Brazil. Electronic address: mjotoledo@uem.br.
authors.forename: Max Jean de Ornelas
authors.initials: MJ
authors.lastname: Toledo
mesh_terms: D000818:Animals; D001921:Brain / Q000469:parasitology / Q000473:pathology; D001938:Brazil / Q000453:epidemiology; D014355:Chagas Disease / Q000453:epidemiology / Q000469:parasitology* / Q000473:pathology; D006321:Heart / Q000469:parasitology; D006614:Hindlimb; D008099:Liver / Q000469:parasitology / Q000473:pathology; D008297:Male; D051379:Mice; D018482:Muscle, Skeletal / Q000469:parasitology / Q000473:pathology; D009206:Myocardium / Q000473:pathology; D018512:Parasitemia / Q000453:epidemiology / Q000469:parasitology / Q000473:pathology; D013154:Spleen / Q000469:parasitology / Q000473:pathology; D014349:Trypanosoma cruzi / Q000145:classification / Q000472:pathogenicity*
keywords: Amazon; DTUs; Mice; Pathogenicity; Trypanosoma cruzi