Characterization of insecticide resistance in populations of Triatominae (Hemiptera: Reduviidae), vectors of Trypanosoma cruzi Chagas, 1909

Introduction Chagas disease (CD) is still considered an important public health problem in several Latin American countries. In these areas, at least 12 to 14 million people are infected with Trypanosoma cruzi Chagas, 1909 and approximately 28 million are at risk of contamination. Without vaccines and efficient treatment, control of CD relies mostly on vector-control with residual spraying of insecticides. Currently, there are records of outbreaks of resistant populations of Triatoma infestans Klug, 1834 to deltamethrin, -cypermethrin and -cyfluthrin in northern Argentina and southern Bolivia. In Brazil, populations of Triatoma sordida Stål, 1859 has been detected with initial resistance to deltamethrin in the municipalities of Bocaiúva and Coração de Jesus in the State of Minas Gerais. Objectives - Analyze the levels of resistance of Panstrongylus megistus Burmeister, 1835; Triatoma brasiliensis Neiva, 1911 and T. sordida to deltamethrin. Describing the interaction of this compound in the dorsal cuticle of nymphs of the 1st stage. Standardize field bioassays for study of resistance in triatomine populations. Methods - In this thesis, dose-response bioassays were made with reference colony, comparing them with field populations originating from eleven endemic states of Brazil. In addition, the Scanning Electron Microscopy (SEM) was used to study the cuticle of first instar nymphs treated with different concentrations of deltamethrin. Field bioassays were conducted using substrates of mud, brick and wood. The results of dose response bioassays were estimated by Probit analysis. Differences between populations were established by ANOVA and Tukey test. Results The level resitance to deltamethrin of 38 triatomines populations were evaluated in the biennium 2008-2009. It was detected for the first time, low-level resistance to the population of P. megistus, 10 municipality of Serranópolis Iguaçu/PR. However, due to the wide geographical distribution...