title: Insecticide resistance in vector Chagas disease: evolution, mechanisms and management.
abstract: Chagas disease is a chronic parasitic infection restricted to America. The disease is caused by the protozoa Trypanosoma cruzi, which is transmitted to human through the feces of infected triatomine insects. Because no treatment is available for the chronic forms of the disease, vector chemical control represents the best way to reduce the incidence of the disease. Chemical control has been based principally on spraying dwellings with insecticide formulations and led to the reduction of triatomine distribution and consequent interruption of disease transmission in several areas from endemic region. However, in the last decade it has been repeatedly reported the presence triatomnes, mainly Triatoma infestans, after spraying with pyrethroid insecticides, which was associated to evolution to insecticide resistance. In this paper the evolution of insecticide resistance in triatomines is reviewed. The insecticide resistance was detected in 1970s in Rhodnius prolixus and 1990s in R. prolixus and T. infestans, but not until the 2000s resistance to pyrthroids in T. infestans associated to control failures was described in Argentina and Bolivia. The main resistance mechanisms (i.e. enhanced metabolism, altered site of action and reduced penetration) were described in the T. infestans resistant to pyrethrods. Different resistant profiles were demonstrated suggesting independent origin of the different resistant foci of Argentina and Bolivia. The deltamethrin resistance in T. infestans was showed to be controlled by semi-dominant, autosomally inherited factors. Reproductive and developmental costs were also demonstrated for the resistant T. infestans. A discussion about resistance and tolerance concepts and the persistence of T. infestans in Gran Chaco region are presented. In addition, theoretical concepts related to toxicological, evolutionary and ecological aspects of insecticide resistance are discussed in order to understand the particular scenario of pyrethroid resistance in triatomines.
authors.affiliation: Centro de Investigaciones de Plagas e Insecticidas (CIPEIN), Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Investigaciones Científicas y Técnicas para la Defensa (CONICET-CITEDEF), Buenos Aires, Argentina; Centro de Referencia de Vectores (CeReVe), Dirección de Enfermedades Transmisibles por Vectores, Ministerio de Salud de la Nación Argentina, Santa María de Punilla, Córdoba, Argentina. Electronic address: gmougabure@gmail.com.
authors.forename: Gastón
authors.initials: G
authors.lastname: Mougabure-Cueto
authors.affiliation: Centro de Investigaciones de Plagas e Insecticidas (CIPEIN), Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Investigaciones Científicas y Técnicas para la Defensa (CONICET-CITEDEF), Buenos Aires, Argentina. Electronic address: mpicollo@gmail.com.
authors.forename: María Inés
authors.initials: MI
authors.lastname: Picollo
mesh_terms: D000818:Animals; D001118:Argentina; D005075:Biological Evolution; D001838:Bolivia; D014355:Chagas Disease / Q000635:transmission*; D006801:Humans; D007300:Insect Control; D007303:Insect Vectors / Q000187:drug effects / Q000235:genetics* / Q000469:parasitology; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides / Q000494:pharmacology; D009570:Nitriles / Q000494:pharmacology; D011722:Pyrethrins / Q000494:pharmacology; D012239:Rhodnius / Q000187:drug effects / Q000235:genetics* / Q000469:parasitology; D014224:Triatoma / Q000187:drug effects / Q000235:genetics* / Q000469:parasitology; D014349:Trypanosoma cruzi
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin
keywords: Chagas disease; Chemical control; Insecticide resistance; Pyrethroids; Triatoma infestans; Triatominae