| Title: | Post-control surveillance of Triatoma infestans and Triatoma sordida with chemically-baited sticky traps |
| Author(s): | Rojas de Arias A; Abad-Franch F; Acosta N; Lopez E; Gonzalez N; Zerba E; Tarelli G; Masuh H; |
| Address: | "Centro para el Desarrollo de la Investigacion Cientifica, Diaz Gill Medicina Laboratorial/Fundacion Moises Bertoni, Asuncion, Paraguay. rojasdearias@gmail.com" |
| DOI: | 10.1371/journal.pntd.0001822 |
| ISSN/ISBN: | 1935-2735 (Electronic) 1935-2727 (Print) 1935-2727 (Linking) |
| Abstract: | "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 approximately 0.40-0.50 for baited and at just p approximately 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 approximately 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" |
| Keywords: | Animals Chagas Disease/*prevention & control Entomology/*methods Female Humans Insect Control/*methods Insecticides/*administration & dosage Sensitivity and Specificity Triatoma/*growth & development; |
| Notes: | "MedlineRojas de Arias, Antonieta Abad-Franch, Fernando Acosta, Nidia Lopez, Elsa Gonzalez, Nilsa Zerba, Eduardo Tarelli, Guillermo Masuh, Hector eng Evaluation Study Research Support, Non-U.S. Gov't 2012/10/03 PLoS Negl Trop Dis. 2012; 6(9):e1822. doi: 10.1371/journal.pntd.0001822. Epub 2012 Sep 13" |
