title: Deltamethrin toxicological profile of peridomestic Triatoma sordida in the North of Minas Gerais, Brazil.
abstract: BACKGROUND
  In general, there was a large reduction in the occurrence of cases of Chagas disease in the last decades in Brazil. However, despite all of these efforts, there have been various reports of persistent reinfestations of T. sordida in a large part of the state of Minas Gerais, for reasons still little investigated. Thus, this purpose of this study was to characterize the deltamethrin susceptibility profile of peridomestic T. sordida populations from North of Minas Gerais-Brazil.
  
  
  METHODS
  Susceptibility to deltamethrin was assessed in seventeen peridomestic populations of T. sordida from North region of Minas Gerais, Brazil. Serial dilutions of deltamethrin in acetone (0.2 μL) were topically applied in first instar nymphs (F1, five days old, fasting, weight 1.2 ± 0.2 mg). Dose response results were analyzed with POLO program, determining the lethal doses, slope and resistance ratios (RR).
  
  
  RESULTS
  Susceptibility profile characterization of T. sordida populations revealed resistance ratios (RR50) ranging from 2.50 to 7.08.
  
  
  CONCLUSIONS
  In fact, we know very little about the real impact of the resistance ratios obtained in the laboratory bioassays on the effectiveness of the vector control activities in the field. Thus, we prefer to refer to the populations with RR > 5 as populations with altered susceptibility. For these populations, the realization of laboratory and field trials, simultaneous and complementary, permitting the evaluation of both, is recommended.
authors.affiliation: Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas/CPqRR/FIOCRUZ, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima 1715, Barro Preto, 29190-002, Belo Horizonte, MG, Brazil. grasielle@cpqrr.fiocruz.br.
authors.forename: Grasielle Caldas Dávila
authors.initials: GC
authors.lastname: Pessoa
authors.affiliation: Laboratório de Entomologia, Universidade Federal de Brasília, Brasília, DF, Brazil. marcos.obara@gmail.com.
authors.forename: Marcos Takashi
authors.initials: MT
authors.lastname: Obara
authors.affiliation: Gerência Regional de Saúde de Montes Claros, Montes Claros, MG, Brazil. joao.rezende@saude.mg.gov.br.
authors.forename: João G
authors.initials: JG
authors.lastname: Rezende
authors.affiliation: Secretaria de Saúde do Estado de Minas Gerais, Belo Horizonte, MG, Brazil. bernardinovazdemelo@yahoo.com.br.
authors.forename: Bernardino Vaz
authors.initials: BV
authors.lastname: de Mello
authors.affiliation: Secretaria de Saúde do Estado de Minas Gerais, Belo Horizonte, MG, Brazil. marcela.ferraz@saude.mg.gov.br.
authors.forename: Marcela Lencine
authors.initials: ML
authors.lastname: Ferraz
authors.affiliation: Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas/CPqRR/FIOCRUZ, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima 1715, Barro Preto, 29190-002, Belo Horizonte, MG, Brazil. diotaiuti@cpqrr.fiocruz.br.
authors.forename: Liléia
authors.initials: L
authors.lastname: Diotaiuti
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D014355:Chagas Disease / Q000635:transmission*; D006801:Humans; D007303:Insect Vectors / Q000187:drug effects*; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D009570:Nitriles / Q000494:pharmacology*; D009758:Nymph; D011722:Pyrethrins / Q000494:pharmacology*; D014224:Triatoma / Q000187:drug effects*; D014349:Trypanosoma cruzi / Q000502:physiology*
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin