title: Variability of susceptibility to deltamethrin in peridomestic Triatoma sordida from Triângulo Mineiro, State of Minas Gerais, Brazil.
abstract: BACKGROUND
  Despite chemical and physical vector control strategies, persistent infestations of Triatoma sordida have been reported in a large part of Minas Gerais, Brazil, and the cause for this is little investigated. We aimed to characterize the deltamethrin toxicological profile in peridomestic T. sordidapopulations from Triângulo Mineiro area of Minas Gerais.
  
  
  METHODS
  Susceptibility to deltamethrin was assessed in seventeen peridomestic T. sordida populations. Serial dilutions of deltamethrin in acetone (0.2µL) were topically applied on the first instar nymphs (F1; five days old; fasting weight, 1.2 ± 0.2mg). Dose response results were analyzed using Probit software, and the lethal doses, slope and resistance ratios were determined. Qualitative tests were also performed.
  
  
  RESULTS
  The deltamethrin susceptibility profile of T. sordida populations revealed resistance ratios ranging from 0.84 to 2.8. The percentage mortality in response to a diagnostic dose was 100.0% in all populations.
  
  
  CONCLUSIONS
  From our results, the lack of resistance to insecticides but persistent T. sordida infestations in the Triângulo Mineiro area may be because of: 1) environmental degradation facilitating dispersion of T. sordida, allowing colonization in artificial ecotopes; 2) operational failures; and 3) complexity of the peridomicile in the study area.These variables are being investigated.
authors: Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, BR.
authors: Grasielle Caldas Dávila
authors: GC
authors: Pessoa
authors: Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, BR.
authors: Tamara Rodrigues Martins
authors: TR
authors: dos Santos
authors: Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, BR.
authors: Gabriela Chadid
authors: GC
authors: Salazar
authors: Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, BR.
authors: Letícia Sena
authors: LS
authors: Dias
authors: Secretaria de Saúde do Estado de Minas Gerais, Governo do Estado de Minas Gerais, Belo Horizonte, Minas Gerais, BR.
authors: Bernardino Vaz
authors: BV
authors: de Mello
authors: Secretaria de Saúde do Estado de Minas Gerais, Governo do Estado de Minas Gerais, Belo Horizonte, Minas Gerais, BR.
authors: Marcela Lencine
authors: ML
authors: Ferraz
authors: Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, BR.
authors: Liléia
authors: L
authors: Diotaiuti
mesh_terms: D000818:Animals; D001681:Biological Assay; D001938:Brazil; D014355:Chagas Disease / Q000635:transmission; D007306:Insecticides; D007928:Lethal Dose 50; D009570:Nitriles; D011722:Pyrethrins; D014224:Triatoma
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin