Long-lasting residual efficacy of a new indoor residual spraying product, VECTRON ™ T500 (broflanilide), against pyrethroid-resistant malaria vectors and its acceptance in a community trial in Burkina Faso.

Autor: Hien AS; Institut de Recherches en Sciences de la Santé, Centre National de la Recherche Scientifique et Technologique, Ouagadougou, Burkina Faso. aristide.hien@yahoo.fr., Bayili K; Institut de Recherches en Sciences de la Santé, Centre National de la Recherche Scientifique et Technologique, Ouagadougou, Burkina Faso., Maiga S; Institut de Recherches en Sciences de la Santé, Centre National de la Recherche Scientifique et Technologique, Ouagadougou, Burkina Faso., Oumbouke W; Innovative Vector Control Consortium (IVCC), Liverpool, UK., Birba J; Institut de Recherches en Sciences de la Santé, Centre National de la Recherche Scientifique et Technologique, Ouagadougou, Burkina Faso., Soma DD; Institut de Recherches en Sciences de la Santé, Centre National de la Recherche Scientifique et Technologique, Ouagadougou, Burkina Faso., Ouattara AY; Institut de Recherches en Sciences de la Santé, Centre National de la Recherche Scientifique et Technologique, Ouagadougou, Burkina Faso., Karama DO; Institut de Recherches en Sciences de la Santé, Centre National de la Recherche Scientifique et Technologique, Ouagadougou, Burkina Faso., Coleman M; Innovative Vector Control Consortium (IVCC), Liverpool, UK., Snetselaar J; Innovative Vector Control Consortium (IVCC), Liverpool, UK., Small G; Innovative Vector Control Consortium (IVCC), Liverpool, UK., Niimi S; Mitsui Chemicals Crop & Life Solutions, Inc., Tokyo, Japan., Ayumi K; Mitsui Chemicals Crop & Life Solutions, Inc., Tokyo, Japan., Kompaoré S; Permanent Secretariat for Malaria Elimination, Ouagadougou, Burkina Faso., Tsuchiya K; Mitsui Chemicals Crop & Life Solutions, Inc., Tokyo, Japan., Dabiré RK; Institut de Recherches en Sciences de la Santé, Centre National de la Recherche Scientifique et Technologique, Ouagadougou, Burkina Faso., Diabaté A; Institut de Recherches en Sciences de la Santé, Centre National de la Recherche Scientifique et Technologique, Ouagadougou, Burkina Faso.
Jazyk: angličtina
Zdroj: Parasites & vectors [Parasit Vectors] 2024 Nov 23; Vol. 17 (1), pp. 484. Date of Electronic Publication: 2024 Nov 23.
DOI: 10.1186/s13071-024-06577-y
Abstrakt: Background: The WHO Global Malaria Programme advocates for a comprehensive, strategic approach to managing insecticide resistance, highlighting the importance of using multiple insecticides with different modes of action through rotations and combinations. To slow the spread of resistance, it is essential to develop and evaluate new formulations that feature unique modes of action and extended residual effects. Addressing this need, Mitsui Chemicals Crop & Life Solutions, Inc., developed VECTRON™ T500, a new indoor residual spraying (IRS) formulation using broflanilide, applied at a dosage of 100 mg AI/m 2 . This formulation was tested in a Phase III community trial, alongside Actellic ® 300CS, a commonly used IRS product containing pirimiphos-methyl, applied at the recommended dosage of 1000 mg AI/m 2 .
Methods: Monthly WHO wall cone bioassays were performed to assess the efficacy of the interventions using three mosquito strains: the laboratory-bred, insecticide-susceptible Anopheles gambiae s.s. Kisumu strain, the insecticide-resistant Anopheles coluzzii VKPer strain, and wild Anopheles gambiae s.l. mosquitoes from the Vallée du Kou, where the study was conducted. Vector surveillance was carried out to compare the results between sites treated with VECTRON™ T500, Actellic ® 300CS, and an untreated control site. In addition, any reported adverse effects were closely monitored to evaluate the community's acceptance of VECTRON ™ T500.
Results: VECTRON™ T500 consistently achieved 100% mortality across all wall types for both susceptible and resistant mosquito strains over the 12-month period. In comparison, Actellic ® 300CS induced < 80% mortality for both strains, irrespective of the wall substrate. When assessing delayed mortality in An. gambiae s.l. mosquitoes collected from sites treated with Actellic ® 300CS (VK1) and VECTRON™ T500 (VK3), a statistically significant difference was noted after a 72-h holding period compared to the control site (RR = 0.51, CI95% = [0.31-0.6], P = 0.0026). Additionally, no adverse events were reported in households sprayed with VECTRON™ T500.
Conclusions: The residual efficacy of VECTRON ™ T500 extended for 12 months post-spraying, effectively covering the full malaria transmission season while maintaining high mortality rates in pyrethroid-resistant malaria vectors. VECTRON ™ T500 demonstrated non-inferiority in performance compared to Actellic ® 300CS, the standard reference product. This new IRS formulation has the potential to play a crucial role in managing insecticide resistance by being integrated into a rotational strategy alongside other IRS products containing insecticides with different modes of action.
Competing Interests: Declarations. Ethics approval and consent to participate: An information consent form, translated into the local language, was provided to the heads of households. Furthermore, informed consent was obtained from the volunteer mosquito collectors. The mosquito collectors were exclusively male individuals between the ages of 18 and 40, members of the local community, who were recruited and trained for this role. Collectors were permitted to withdraw from the trial at any time. They were subject to regular examination by a study physician for clinical indications of malaria while participating in the study. In the event of a positive diagnosis, they were referred to the nearest local health centre for free treatment. Furthermore, mosquito collectors were afforded free access to malaria diagnosis and treatment for a period of up to 1 month following the conclusion of the study. A study physician at the local public health facility was responsible for the administration of all medical care under the project. Spray operators were required to be male, at least 18 years of age, physically fit, and in good health. They were also expected to have no obvious disabilities that would limit their mobility and to possess sufficient literacy in French to enable them to follow all insecticide handling procedures in a safe manner. Prior to their participation in the study, all participants, including heads of households and mosquito collectors, provided written informed consent. Furthermore, this study was approved by the ethics committee and registered under the number 15-2021/CEIRES on April 6, 2021. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.
(© 2024. The Author(s).)
Databáze: MEDLINE
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