title: First report of the Phe1534Cys kdr mutation in natural populations of Aedes albopictus from Brazil.
abstract: Knockdown resistance (kdr), caused by alterations in the voltage-gated sodium channel (NaV), is one of the mechanisms responsible for pyrethroid (PY) resistance. In the Asian tiger mosquito, Aedes albopictus, at least four different mutations were described in the IIIS6 NaVsegment in populations from Asia, North America and Europe. In contrast, in Aedes aegypti at least 12 non-synonymous mutations have been reported at nine different codons, mostly in the IIS6 and IIIS6 NaVsegments. The Phe1534Cys kdr mutation in the IIIS6 NaVsegment is the most prevalent in populations of Ae. aegypti worldwide, also found in Ae. albopictus from Singapore. Herein, we investigated the DNA diversity corresponding to the IIS6 and IIIS6 NaVsegments in natural populations of Ae. albopictus from Brazil.
  
  
  
  DNA from eight Brazilian Ae. albopictus natural populations were individually extracted and pooled by states of origin, amplified, cloned and sequenced for the corresponding IIS6 and IIIS6 NaVsegments. Additionally, samples from each location were individually genotyped by an allelic specific PCR (AS-PCR) approach to obtain the genotypic and allelic frequencies for the 1534 NaVsite.
  
  
  
  No non-synonymous substitutions were observed in the IIS6 sequences. However, the Phe1534Cys kdr mutation was evidenced in the Ae. albopictus NaVIIIS6 segment sequences from Paraná (PR) and Rondônia (RO) states, but not from Mato Grosso (MT) state. The 1534Cyskdrallele varied from 3% (Marilena/PR and Porto Velho/RO) to 10% (Foz do Iguaçu/PR). To our knowledge, this paper reports the first occurrence and provides distribution data of a possible kdr mutation in Ae. albopictus in South America.
  
  
  
  The emergence of a likely kdr mutation in Ae. albopitus natural populations is a signal of alert for vector control measures since PY are the most popular insecticides adopted by residents. Additionally, once the kdr allele is present, its frequency tends to increase faster under exposition to those compounds. Although the Asian tiger mosquito is not incriminated as an important vector of dengue, chikungunya and Zika viruses in South America, its importance in this regard has been extensively discussed since Ae. albopictus is rapidly spreading and can also migrate between sylvatic and urban environments. Therefore, insecticide resistance monitoring initiatives should also be extended to Ae. albopictus in Brazil in order to maintain chemical compounds as an efficient vector control tool when needed.
authors.affiliation: Laboratório de Entomologia Médica e Veterinária, Setor de Ciências Biológicas, Departamento de Zoologia, Universidade Federal do Paraná, PO Box 19020, Curitiba, 81531-980, Paraná, Brazil.
authors.forename: Oscar Alexander
authors.initials: OA
authors.lastname: Aguirre-Obando
authors.affiliation: Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz-FIOCRUZ, Av. Brasil 4365, Rio de Janeiro-RJ, PO Box 2104-900, Brazil. ademirjr@ioc.fiocruz.br.|Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil. ademirjr@ioc.fiocruz.br.
authors.forename: Ademir Jesus
authors.initials: AJ
authors.lastname: Martins
authors.affiliation: Laboratório de Entomologia Médica e Veterinária, Setor de Ciências Biológicas, Departamento de Zoologia, Universidade Federal do Paraná, PO Box 19020, Curitiba, 81531-980, Paraná, Brazil.
authors.forename: Mário Antônio
authors.initials: MA
authors.lastname: Navarro-Silva
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000235:genetics* / Q000821:virology; D000483:Alleles; D000818:Animals; D001208:Asia; D001938:Brazil; D065632:Chikungunya Fever / Q000517:prevention & control / Q000635:transmission / Q000821:virology; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D003715:Dengue / Q000517:prevention & control / Q000635:transmission / Q000821:virology; D005060:Europe; D005787:Gene Frequency; D017344:Genes, Insect; D005838:Genotype; D007305:Insecticide Resistance / Q000235:genetics*; D000072138:Mosquito Vectors / Q000235:genetics* / Q000821:virology; D009154:Mutation; D009656:North America; D016133:Polymerase Chain Reaction; D011722:Pyrethrins; D012846:Singapore; D000071243:Zika Virus Infection / Q000517:prevention & control / Q000635:transmission / Q000821:virology
chemical_list: D011722:Pyrethrins; D004247:DNA
keywords: Allele-specific PCR; Chikungunya; Dengue; Pyrethroid resistance; Vector control; Voltage-gated sodium channel; Zika