Are the populations of Triatoma infestans from Santiago del Estero, Argentina, resistant to pyrethroids?

GOMEZ-BRAVO A; VASSENA CV; ALZOGARAY RA; ZERBA EN; ABRIL MC

Atlanta

Congreso; 65th Annual Meeting of the American Society of Tropical Medicine and Hygiene; 2016

American Society of Tropical Medicine and Hygiene

Under the vector surveillance and control program for Triatoma infestansthat Mundo Sano has in place since 2002 in the urban and surroundingrural areas of Añatuya (Santiago del Estero Province), monitoring ofinsecticide resistance was implemented in 2014. The objective was toevaluate the susceptibility of T. infestans samples from this area to thepyrethroid deltamethrin, active ingredient found in the most widely usedformulations for triatomine control. Bioassays were performed followingthe World Health Organization protocol for the evaluation of insecticidaleffect on triatomines. First instar nymphs obtained in the laboratory fromadult insects collected in the feld (F1 generation) were used. Mortality wasevaluated 24 hours after topical application of the discriminant dose (2ng/insect). The CIPEIN and La Pista (resistant to deltamethrin) strains wereused as negative and positive controls, respectively. Possible resistancewas considered when survival was observed in at least one insect in twoof every three independent assays. Percent mortality for the differentcollection sites were: El Desvio 90%; Barrio Sportivo, 75%; Miel de Palo,70%; Lote 47, 38%. These results suggest that some of the populationsevaluated present early-stage resistance to deltamethrin. New assays willbe conducted in order to quantify this phenomenon with greater precision.