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Improving houses in the Bolivian Chaco increases effectiveness of residual insecticide spraying against infestation with Triatoma infestans , vector of Chagas disease
Author(s) -
Gonçalves Raquel,
Landivar Daniel,
Grover Sañez Liendo Edson,
Mamani Fernandez Janet,
Ismail Hanafy M.,
Paine Mark J. I.,
Courtenay Orin,
Bern Caryn
Publication year - 2021
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/tmi.13640
Subject(s) - triatoma infestans , infestation , triatoma , vector (molecular biology) , toxicology , biology , veterinary medicine , environmental health , ecology , medicine , agronomy , trypanosoma cruzi , reduviidae , parasite hosting , biochemistry , heteroptera , world wide web , computer science , gene , recombinant dna
Objective Failure to control domestic Triatoma infestans in the Chaco is attributed to vulnerable adobe construction, which provides vector refuges and diminishes insecticide contact. We conducted a pilot to test the impact of housing improvement plus indoor residual spraying (IRS) on house infestation and vector abundance in a rural community in the Bolivian Chaco. Methods The intervention included three arms: housing improvement + IRS [HI], assisted IRS [AS] in which the team helped to clear the house pre‐IRS and routine IRS [RS]. HI used locally available materials, traditional construction techniques and community participation. Vector parameters were assessed by Timed Manual Capture for 2 person‐hours per house at baseline and medians of 114, 173, 314, 389 and 445 days post‐IRS‐1. A second IRS round was applied at a median of 314 days post‐IRS‐1. Results Post‐intervention infestation indices and abundance fell in all three arms. The mean odds of infestation was 0.29 (95% CL 0.124, 0.684) in the HI relative to the RS arm. No difference was observed between AS and RS. Vector abundance was reduced by a mean 44% (24.8, 58.0) in HI compared to RS, with no difference between AS and RS. Median delivered insecticide concentrations per house were lower than the target of 50 mg/m 2 in >90% of houses in all arms. Conclusion Housing improvement using local materials and community participation is a promising strategy to improve IRS effectiveness in the Bolivian Chaco. A larger trial is needed to quantify the impact on reinfestation over time.