Open AccessPost-Control Surveillance of Triatoma infestans and Triatoma sordida with Chemically-Baited Sticky Traps
Author(s) -
Antonieta Rojas de Arias,
Fernando AbadFranch,
Nidia Acosta,
Elsa López,
Nery Sablón González,
Eduardo Zerba,
Guillermo Tarelli,
Héctor Mario Masuh
Publication year - 2012
Publication title -
plos neglected tropical diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.99
H-Index - 135
eISSN - 1935-2735
pISSN - 1935-2727
DOI - 10.1371/journal.pntd.0001822
Subject(s) - triatoma infestans , infestation , triatoma , vector (molecular biology) , biology , toxicology , veterinary medicine , ecology , heteroptera , reduviidae , horticulture , medicine , trypanosoma cruzi , parasite hosting , biochemistry , world wide web , computer science , gene , recombinant dna
Background Chagas disease prevention critically depends on keeping houses free of triatomine vectors. Insecticide spraying is very effective, but re-infestation of treated dwellings is commonplace. Early detection-elimination of re-infestation foci is key to long-term control; however, all available vector-detection methods have low sensitivity. Chemically-baited traps are widely used in vector and pest control-surveillance systems; here, we test this approach for Triatoma spp. detection under field conditions in the Gran Chaco. Methodology/Principal Findings Using a repeated-sampling approach and logistic models that explicitly take detection failures into account, we simultaneously estimate vector occurrence and detection probabilities. We then model detection probabilities (conditioned on vector occurrence) as a function of trapping system to measure the effect of chemical baits. We find a positive effect of baits after three (odds ratio [OR] 5.10; 95% confidence interval [CI 95 ] 2.59–10.04) and six months (OR 2.20, CI 95 1.04–4.65). Detection probabilities are estimated at p ≈0.40–0.50 for baited and at just p ≈0.15 for control traps. Bait effect is very strong on T. infestans (three-month assessment: OR 12.30, CI 95 4.44–34.10; p ≈0.64), whereas T. sordida is captured with similar frequency in baited and unbaited traps. Conclusions/Significance Chemically-baited traps hold promise for T. infestans surveillance; the sensitivity of the system at detecting small re-infestation foci rises from 12.5% to 63.6% when traps are baited with semiochemicals. Accounting for imperfect detection, infestation is estimated at 26% (CI 95 16–40) after three and 20% (CI 95 11–34) after six months. In the same assessments, traps detected infestation in 14% and 8.5% of dwellings, whereas timed manual searches (the standard approach) did so in just 1.4% of dwellings only in the first survey. Since infestation rates are the main indicator used for decision-making in control programs, the approach we present may help improve T. infestans surveillance and control program management.