title: A new approach to characterization of the resistance of populations of Rhipicephalus microplus (Acari: Ixodidae) to organophosphate and pyrethroid in the state of Minas Gerais, Brazil.
abstract: The monitoring of resistance of cattle tick populations in Brazil to the chemical bases in use is largely limited to investigation of the phenotypic profile. There are few studies investigating the role played by the genotypic profile in acaricide resistance in the country. Therefore, the aim of the present study was to carry out molecular characterization and trace out the genetic profile of populations of Rhipicephalus microplus with respect to resistance to the organophosphate and pyrethroid chemical groups. For that purpose, larvae were genotyped belonging to 587 populations for pyrethroids and 306 for organophosphates, using the polymerase chain reaction technique. It was found that 75.49% and 97.44% of the larvae studied showed resistance to the organophosphates and pyrethroids, respectively. Among the populations resistant to pyrethroids, 91.9% were heterozygotes, showing that most of the resistant populations have only one allele responsible for resistance. Therefore, it is possible to conclude that the genotyped populations have high resistance to organophosphates, and even more so to pyrethroids. This information is fundamental for understanding the mechanisms of resistance of R. microplus to acaricides, to enable improvement of control techniques.
authors: Programa de Pós-graduação em Biologia e Comportamento Animal da Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil. alinefaza@yahoo.com.br
authors: Aline Pasqualini
authors: AP
authors: Faza
authors: Isabella Silvestre Barreto
authors: IS
authors: Pinto
authors: Isabela
authors: I
authors: Fonseca
authors: Gustavo Resende
authors: GR
authors: Antunes
authors: Caio Márcio de Oliveira
authors: CM
authors: Monteiro
authors: Erik
authors: E
authors: Daemon
authors: Michelle de Souza
authors: Mde S
authors: Muniz
authors: Marta Fonseca
authors: MF
authors: Martins
authors: John
authors: J
authors: Furlong
authors: Márcia Cristina de Azevedo
authors: MC
authors: Prata
mesh_terms: D000818:Animals; D001938:Brazil; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology / Q000517:prevention & control; D005838:Genotype; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides; D007814:Larva; D010755:Organophosphates; D011722:Pyrethrins; D048494:Rhipicephalus / Q000145:classification / Q000235:genetics*; D013984:Tick Infestations / Q000469:parasitology / Q000517:prevention & control / Q000662:veterinary
chemical_list: D007306:Insecticides; D010755:Organophosphates; D011722:Pyrethrins
keywords: Cattle tick; Genotypic; Organophosphates; Pyrethroids