Susceptibility and resistance to insecticides of Chagas disease vectors

Chemical control of Chagas disease vectors appears to be the best practical way to reduce the incidence of the disease. DDT was initially tested in th e 1950s for the campaigns of control of Chagas disease vectors. Its low lev el of effectiveness against triatomine caused the failure of these control actions. HCH was then introduced in the southern cone and Dieldrin in the n orth of Latinoamerica. Starting in the late 1960s anticholinesterasic organ ophosphorus and carbamate compounds were introduced in the control of Chaga s vectors. The use of pyrethroid compounds began in 1980. This family of in secticides is now the most important tool in triatomines control because of its favorable toxicological properties. Other types of insecticides also s tudied for Chagas vector control were the insect growth regulators and the antifeeding compounds. Because of the mode of action of these insecticides they are now considered just a potential complement of neurotoxic insectici des for integrated programmes of Triatomines control. Innovative formulatio ns such as fumigant canister and insecticidal paints have been successfully developed in Latinoamerica with the World Health Organization support. Res istance to insecticides of triatomines is not yet a great problem in Chagas vectors. However, some resistant strains to pyrethroids have been found in Rhodnius prolixus from Venezuela and in Triatoma infestans from Brazil. So me cases of T. infestans incipient resistance to deltamethrin have been det ected in Argentina. According to the control tools now available it is poss ible to expect the interruption of vector transmission of Chagas disease in the near future.