title: Kdr mutations in Triatoma infestans from the Gran Chaco are distributed in two differentiated foci: Implications for pyrethroid resistance management.
abstract: Point mutations in the voltage-gated sodium channel, the primary target of pyrethroid insecticides, have been associated with the resistance in Triatoma infestans, an important vector of Chagas' disease. Hence, the sustainability of vector control programs requires the implementation of resistance management strategies. We determined the sensitivity of the molecular assays previously designed for early resistance detection to be used in pooled samples from a wide area of the endemic region, and validated them for their routine use in control campaigns for the monitoring of insecticide resistance in T. infestans. Consequently, we used these methods to examine the distribution of resistance-associated mutations in the sodium channel gene in populations of T. infestans from the Argentinean and Bolivian Gran Chaco. The PASA and REA assays tested proved sensitive enough to detect kdr SNPs in pooled samples, indicating these assays are suitable for routine screening in insecticide resistance surveillance. Two geographically differentiated foci were detected in T. infestans populations from the Argentinean and Bolivian Gran Chaco, with populations on the Bolivian-Argentinean border carrying L1014F mutation, and those from the Argentinean Chaco carrying L925I mutation. In all highly resistant populations analyzed, one of both kdr mutations was present, and toxicological assays determined that all pyrethroid resistant populations analyzed herein were sensitive to fenitrothion. The principal cause of pyrethroid resistance in T. infestans from the Gran Chaco ecoregion is kdr mutations in the sodium channel. Different levels of resistance occur in different populations carrying identical mutation, suggesting the existence of contributory mechanisms.
authors.affiliation: Laboratorio de Neurobiología de Insectos, Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Buenos Aires, Argentina. Electronic address: sierra.ivana@gmail.com.
authors.forename: Ivana
authors.initials: I
authors.lastname: Sierra
authors.affiliation: Laboratorio de Neurobiología de Insectos, Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Buenos Aires, Argentina. Electronic address: nataliacapriotti@gmail.com.
authors.forename: Natalia
authors.initials: N
authors.lastname: Capriotti
authors.affiliation: Centro de Investigaciones de Plagas e Insecticidas-CIPEIN (CONICET-CITEDEF), Juan B de La Salle 4397, Villa Martelli, Buenos Aires, Argentina, Argentina. Electronic address: georginafronza@gmail.com.
authors.forename: Georgina
authors.initials: G
authors.lastname: Fronza
authors.affiliation: Centro de Investigaciones de Plagas e Insecticidas-CIPEIN (CONICET-CITEDEF), Juan B de La Salle 4397, Villa Martelli, Buenos Aires, Argentina, Argentina. Electronic address: gmougabure@gmail.com.
authors.forename: Gastón
authors.initials: G
authors.lastname: Mougabure-Cueto
authors.affiliation: Laboratorio de Neurobiología de Insectos, Centro Regional de Estudios Genómicos, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Buenos Aires, Argentina. Electronic address: sheilaons@hotmail.com.
authors.forename: Sheila
authors.initials: S
authors.lastname: Ons
mesh_terms: D000818:Animals; D014355:Chagas Disease / Q000517:prevention & control; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D009154:Mutation; D020641:Polymorphism, Single Nucleotide; D011722:Pyrethrins / Q000494:pharmacology*; D015222:Sodium Channels / Q000235:genetics*; D014224:Triatoma / Q000235:genetics*
chemical_list: D007306:Insecticides; D011722:Pyrethrins; D015222:Sodium Channels
keywords: Chagas’disease; Kdr; Pyrethroid resistance; Sodium channel; Triatoma infestans