Geographical Variation of Deltamethrin Susceptibility of Triatoma infestans (Hemiptera: Reduviidae) in Argentina With Emphasis on a Resistant Focus in the Gran Chaco.
Chagas disease is one of the most important parasitic infections in Latin America. The main vector of the protozoan Trypanosoma cruzi in America is Triatoma infestans, a blood-sucking triatomine bug who is widely distributed in the Gran Chaco ecoregion. Control programs in endemic countries are focused in the elimination of triatomine vectors with pyrethroid insecticides. However, chemical control has failed in the Gran Chaco over the last two decades because of several factors. Previous studies have reported the evolution of different levels of resistance to deltamethrin in Tri. infestans Recently, very high resistance has been found in the central area of the Argentine Gran Chaco. However, the origin and the extension of this remarkably resistant focus remain unknown. The aim of this study was to evaluate the geographical variation of deltamethrin susceptibility of Tri. infestans in different endemic provinces of Argentina, with emphasis in the center of the Argentine Gran Chaco ecoregion where this main vector has not been reduced. Populations of Mendoza, San Juan, Santiago del Estero, and Tucumán provinces were all susceptible. Resistant populations were only detected in the province of Chaco, where a mosaic resistant focus was described at the Güemes Department. It was characterized into three pyrethroid resistance categories: susceptible, low, and highly resistant populations. We found the populations with the highest resistance levels to deltamethrin, with resistant ratios over 1000.
Centro de Investigaciones de Plagas e Insecticidas, Unidad de Investigación y desarrollo estratégico para la Defensa/Consejo Nacional de Investigaciones Científicas y Técnicas (CIPEIN, UNIDEF/ CONICET), Juan B. de La Salle 4397, Villa Martelli, Buenos Aires, Argentina, georginafronza@gmail.com.
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Centro de Investigaciones de Plagas e Insecticidas, Unidad de Investigación y desarrollo estratégico para la Defensa/Consejo Nacional de Investigaciones Científicas y Técnicas (CIPEIN, UNIDEF/ CONICET), Juan B. de La Salle 4397, Villa Martelli, Buenos Aires, Argentina.
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Toloza
Centro de Investigaciones de Plagas e Insecticidas, Unidad de Investigación y desarrollo estratégico para la Defensa/Consejo Nacional de Investigaciones Científicas y Técnicas (CIPEIN, UNIDEF/ CONICET), Juan B. de La Salle 4397, Villa Martelli, Buenos Aires, Argentina.
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Picollo
Programa Nacional de Chagas de Argentina, Dirección de Enfermedades Transmisibles por Vectores, Ministerio de Salud de la Nación, 9 de Julio 341, Córdoba, Argentina.
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Spillmann
Centro de Referencia de Vectores (CeReVe), Ministerio de Salud de la Nación, Pabellón Rawson s/n, Santa María de Punilla, Córdoba, Argentina.
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Mougabure-Cueto
D000818:Animals; D001118:Argentina; D014355:Chagas Disease / Q000517:prevention & control; D005260:Female; D005843:Geography; D007303:Insect Vectors / Q000187:drug effects* / Q000502:physiology; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D009570:Nitriles / Q000494:pharmacology*; D009758:Nymph / Q000187:drug effects; D010063:Ovum / Q000187:drug effects; D011722:Pyrethrins / Q000494:pharmacology*; D014224:Triatoma / Q000187:drug effects* / Q000254:growth & development
D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin
Gran Chaco; Triatoma infestans; pyrethroid resistance; toxicological heterogeneity