title: Trypanosoma cruzi IV causing outbreaks of acute Chagas disease and infections by different haplotypes in the Western Brazilian Amazonia.
abstract: BACKGROUND
  Chagas disease is an emergent tropical disease in the Brazilian Amazon Region, with an increasing number of cases in recent decades. In this region, the sylvatic cycle of Trypanosoma cruzi transmission, which constitutes a reservoir of parasites that might be associated with specific molecular, epidemiological and clinical traits, has been little explored. The objective of this work is to genetically characterize stocks of T. cruzi from human cases, triatomines and reservoir mammals in the State of Amazonas, in the Western Brazilian Amazon.
  
  
  RESULTS
  We analyzed 96 T. cruzi samples from four municipalities in distant locations of the State of Amazonas. Molecular characterization of isolated parasites from cultures in LIT medium or directly from vectors or whole human blood was performed by PCR of the non-transcribed spacer of the mini-exon and of the 24 S alfa ribosomal RNA gene, RFLP and sequencing of the mitochondrial cytochrome c oxidase subunit II (COII) gene, and by sequencing of the glucose-phosphate isomerase gene. The T. cruzi parasites from two outbreaks of acute disease were all typed as TcIV. One of the outbreaks was triggered by several haplotypes of the same DTU. TcIV also occurred in isolated cases and in Rhodnius robustus. Incongruence between mitochondrial and nuclear phylogenies is likely to be indicative of historical genetic exchange events resulting in mitochondrial introgression between TcIII and TcIV DTUs from Western Brazilian Amazon. TcI predominated among triatomines and was the unique DTU infecting marsupials.
  
  
  CONCLUSIONS
  DTU TcIV, rarely associated with human Chagas disease in other areas of the Amazon basin, is the major strain responsible for the human infections in the Western Brazilian Amazon, occurring in outbreaks as single or mixed infections by different haplotypes.
authors: Tropical Medicine Foundation Dr. Heitor Vieira Dourado, Manaus, Amazonas, Brazil.
authors: Wuelton Marcelo
authors: WM
authors: Monteiro
authors: Laylah Kelre Costa
authors: LK
authors: Magalhães
authors: Amanda Regina Nichi
authors: AR
authors: de Sá
authors: Mônica Lúcia
authors: ML
authors: Gomes
authors: Max Jean de Ornelas
authors: MJ
authors: Toledo
authors: Lara
authors: L
authors: Borges
authors: Isa
authors: I
authors: Pires
authors: Jorge Augusto de Oliveira
authors: JA
authors: Guerra
authors: Henrique
authors: H
authors: Silveira
authors: Maria das Graças Vale
authors: Md
authors: Barbosa
mesh_terms: D000208:Acute Disease; D000818:Animals; D001938:Brazil / Q000453:epidemiology; D014355:Chagas Disease / Q000453:epidemiology* / Q000235:genetics* / Q000635:transmission; D004272:DNA, Mitochondrial / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D004196:Disease Outbreaks; D003576:Electron Transport Complex IV / Q000235:genetics; D005260:Female; D017125:Genes, Protozoan; D020459:Genes, rRNA / Q000235:genetics; D006239:Haplotypes; D006801:Humans; D008297:Male; D008394:Marsupialia / Q000469:parasitology; D015800:Protozoan Proteins / Q000235:genetics; D014225:Triatominae / Q000469:parasitology; D014349:Trypanosoma cruzi / Q000235:genetics* / Q000472:pathogenicity
chemical_list: D004272:DNA, Mitochondrial; D016054:DNA, Protozoan; D015800:Protozoan Proteins; C117108:cytochrome C oxidase subunit II; D003576:Electron Transport Complex IV