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Insecticide resistance of Triatoma infestans (Hemiptera, Reduviidae) vector of Chagas disease in Bolivia
Author(s) -
Lardeux Frédéric,
Depickère Stéphanie,
Duchon Stéphane,
Chavez Tamara
Publication year - 2010
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1111/j.1365-3156.2010.02573.x
Subject(s) - bendiocarb , deltamethrin , triatoma infestans , reduviidae , malathion , biology , toxicology , piperonyl butoxide , enzootic , pyrethroid , triatominae , veterinary medicine , rhodnius prolixus , hemiptera , pesticide , virology , zoology , medicine , ecology , trypanosoma cruzi , insect , computer science , virus , parasite hosting , world wide web
Summary Objective To define the insecticide resistance status of Triatoma infestans to deltamethrin (pyrethroid), malathion (organophosphate) and bendiocarb (carbamate) in Bolivia. Methods Fifty populations of T. infestans were sampled in Bolivian human dwellings. Quantal response data were obtained by topical applications of 0.2 μl of insecticide–acetone solutions on nymphs N1 of the F1 generations. For most populations, dose–mortality relationships and resistance ratios (RR) were analysed. Discriminating concentrations were established for each insecticide with a susceptible reference strain and used on the other field populations. A tarsal‐contact diagnostic test using insecticide impregnated papers was designed to rapidly identify deltamethrin‐resistant populations in the field. Results Discriminating concentrations for topical applications were 5, 70 and 120 ng active ingredient per insect for deltamethrin, bendiocarb and malathion, respectively. The diagnostic concentration for deltamethrin was 0.30% for the 1‐h exposure by tarsal contact. All populations sampled in human dwellings exhibited significant levels of resistance to deltamethrin, from 6 to 491 and varied among regions. Resistant populations did not recover complete susceptibility to deltamethrin when the synergist piperonyl butoxide (PBO) was used. None of the sampled populations exhibited significant resistance to bendiocarb (all RR 50 < 1.8) or malathion (all RR 50 < 2.2). Conclusion In Bolivia, most ‘domestic’ T. infestans populations are resistant to deltamethrin. Because insecticide vector control is the only selection pressure, resistance likely originates from it. Switching from pyrethroids to organophosphates or carbamates could be a short‐term solution to control this vector, but other alternative integrated control strategies should also be considered in the long term.