Micro-encapsulated pirimiphos-methyl shows high insecticidal efficacy and long residual activity against pyrethroid-resistant malaria vectors in central Côte d’Ivoire

Malaria Journal

Research

Christian Nsanzabana¹  Maiti Laserna de Hipsl²  Jürg Utzinger²  Thomas A Smith²  Olivier JT Briët²  Pie Müller²  Jennifer Donzé³  Emile S Tchicaya⁴  Benjamin G Koudou⁵  Yao Tano⁶ 

[1] Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, OX3 7LE, Oxford, UK;World Wide Antimalarial Resistance Network (WWARN), OX3 7LE, Oxford, UK;Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, CH–4002, Basel, Switzerland;University of Basel, CH–4003, Basel, Switzerland;Department of Parasitology, University of Neuchâtel, CH–2000, Neuchâtel, Switzerland;Département Environnement et Santé, Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan 01, Côte d’Ivoire;Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan 22, Côte d’Ivoire;Département Environnement et Santé, Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan 01, Côte d’Ivoire;Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan 22, Côte d’Ivoire;Centre for Neglected Tropical Diseases, Parasitology Department, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK;Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan 22, Côte d’Ivoire;

关键词: Malaria;    Insecticide resistance;    Indoor residual spraying;    Organophosphates;    Anopheles gambiae;    Hut trial;    Côte d’Ivoire;   

DOI  :  10.1186/1475-2875-13-332

 received in 2014-07-04, accepted in 2014-08-19,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundThe wide-scale implementation of insecticide-treated nets and indoor residual spraying (IRS) has contributed to a considerable decrease of malaria morbidity and mortality in sub-Saharan Africa over the last decade. Due to increasing resistance in Anopheles gambiae sensu lato mosquitoes to dichlorodiphenyl trichloroethane (DDT) and pyrethroids, alternative insecticide formulations for IRS with long-lasting residual activity are required to sustain the gains obtained in most malaria-endemic countries.MethodsThree experimental capsule suspension (CS) formulations of the organophosphate pirimiphos-methyl were evaluated together with Actellic 50 EC, an emulsifiable concentrate (EC) of pirimiphos-methyl, and the pyrethroid ICON 10 CS, a lambda-cyhalothrin CS formulation, in an experimental hut trial. The formulations were tested on two types of surfaces: mud and cement. The study with a 12-month follow-up was carried out in Bouaké, central Côte d’Ivoire, where An. gambiae mosquitoes show high levels of resistance against pyrethroids, DDT and carbamates. Residual activity was also tested in cone bioassays with the susceptible An. gambiae KISUMU strain.ResultsOne of the CS formulations of pirimiphos-methyl, CS BM, outperformed all other formulations tested. On cement surfaces, the odds ratios of overall insecticidal effect on An. gambiae s.l. of pirimiphos-methyl CS BM compared to Actellic 50 EC were 1.4 (95% confidence interval (CI): 1.2–1.7) for the first three months, 5.6 (95% CI: 4.4–7.2) for the second three months, and 3.6 (95% CI: 3.0–4.4) for the last six months of follow-up. On mud surfaces, the respective odds ratios were 2.5 (95% CI: 1.9–3.3), 3.5 (95% CI: 2.7–4.5), and 1.7 (95% CI: 1.4–2.2). On cement, the residual activity of pirimiphos-methyl CS BM measured using cone tests was similar to that of lambda-cyhalothrin and for both treatments, mortality of susceptible Kisumu laboratory strain was not significantly below the World Health Organization pre-set threshold of 80% for 30 weeks after spraying. Residual activity was shorter on mud surfaces, mortality falling below 80% on both pirimiphos-methyl CS BM and lambda-cyhalothrin treated surfaces at 25 weeks post-treatment.ConclusionCS formulations of pirimiphos-methyl are promising alternatives for IRS, as they demonstrate prolonged insecticidal effect and residual activity against malaria mosquitoes.

【 授权许可】

Unknown   
© Tchicaya et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.