Novel insecticides are urgently needed to control insecticide-resistant populations of Anopheles malaria vectors. Broflanilide acts as a non-competitive antagonist of the gamma-aminobutyric acid receptor and has shown prolonged effectiveness as an indoor residual spraying product (VECTRON T500) in experimental hut trials against pyrethroid-resistant vector populations. This multi-centre study expanded upon initial discriminating concentration testing of broflanilide, using six Anopheles insectary colonies (An. gambiae Kisumu KCMUCo, An. gambiae Kisumu NIMR, An. arabiensis KGB, An. arabiensis SENN, An. coluzzii N’Gousso and An. stephensi SK), representing major malaria vector species, to facilitate prospective susceptibility monitoring of this new insecticide; and investigated the potential for cross-resistance to broflanilide via the A296S mutation associated with dieldrin resistance (rdl). Across all vector species tested, the discriminating concentration for broflanilide ranged between LC99 × 2 = 1.126–54.00 μg/ml or LC95 × 3 = 0.7437–17.82 μg/ml. Lower concentrations of broflanilide were required to induce complete mortality of An. arabiensis SENN (dieldrin-resistant), compared to its susceptible counterpart, An. arabiensis KGB, and there was no association between the presence of the rdl mechanism of resistance and survival in broflanilide bioassays, demonstrating a lack of cross-resistance to broflanilide. Study findings provide a benchmark for broflanilide susceptibility monitoring as part of ongoing VECTRON T500 community trials in Tanzania and Benin.
Novel insecticides are urgently needed to control insecticide resistant populations of Anopheles malaria vectors. Broflanilide acts as a non-competitive antagonist of the gamma-aminobutyric acid (GABA) receptor and has shown prolonged effectiveness as an indoor residual spraying (IRS) product (VECTRON™ T500) in experimental hut trials against pyrethroid-resistant vector populations. This multi-centre study expanded upon initial discriminating concentration testing of broflanilide, using six Anopheles insectary colonies (An. gambiae Kisumu KCMUCo, An. gambiae Kisumu NIMR, An. arabiensis KGB, An. arabiensis SENN, An. coluzzii N’Gousso and An. stephensi SK), representing major malaria vector species, to facilitate prospective susceptibility monitoring of this new insecticide; and investigated the potential for cross-resistance to broflanilide via the A296S mutation associated with dieldrin resistance (rdl). Across all vector species tested, the discriminating concentration for broflanilide ranged between LC99x2=1.126 - 54.00 μg/ml or LC95x3=0.7437 - 17.82 μg/ml. Lower concentrations of broflanilide were required to induce complete mortality of An. arabiensis SENN (dieldrin-resistant), compared to its susceptible comparator, An. arabiensis KGB, and there was no association between the presence of the rdlmechanism of resistance and survival in broflanilide bioassays, demonstrating a lack of cross-resistance to broflanilide. Study findings provide a benchmark for broflanilide susceptibility monitoring as part of ongoing VECTRON™ T500 community trials in Tanzania and Benin.
Background: To attain and sustain the universal Long-Lasting Insecticidal Nets (LLINs) coverage, cheap nets that provides equivalent or better protection than the standard LLINs, are required. While it is essential to follow the World Health Organization (WHO) guidelines for the evaluation of LLINs, adherence to the Good Laboratory Practice (GLP) is necessary to generate reliable and reproducible data that will facilitate efficient LLINs to be speedy registered. Adherence to GLP obviate the need to duplicate the assessment and ensures substandard LLINs are not reaching the market. This study aimed to evaluate efficacy of SafeNet NF® and SafeNet® LLIN in accordance to the WHO Pest Evaluation Scheme (WHOPES) and the GLP guidelines. Both candidate LLINs were manufactured with less fabrics to cut down manufacturing costs, motivated by the need for cheaper LLINs to achieve universal coverage. Materials & Methods: SafeNet NF® and SafeNet® LLIN, were assessed in experimental huts against wild, pyrethroid-resistant Anopheles arabiensis mosquitoes. Efficacy in terms of mosquito blood-feeding inhibition and mortality, was compared with Interceptor® LLIN and an untreated net. All nets were washed and artificially holed to simulate a used torn net. The GLP guidelines were followed throughout this study.Results: The mortality of mosquitoes exposed to SafeNet NF® and SafeNet® LLIN were equivalent to that of the reference net. Blood-feeding inhibition was only evident in Interceptor® LLIN. Adherence to GLP was observed throughout the study.Conclusions: Step-wise procedures to conduct LLIN evaluation in compliance to both WHOPES and GLP guidelines are elaborated in this study. SafeNet NF® and SafeNet® LLIN offers equivalent protection as Interceptor® LLIN and can facilitate universal LLIN coverage due to its low manufacturing cost. However, further research is needed to understand durability, acceptability and residual efficacy of these nets in field environments.
Insecticide testing facilities that evaluate a variety of vector control products may generate a large number of hazardous wastes from routine operations. These wastes originate from degraded technical grade materials, sprayed substrates with Indoor Residual Spraying (IRS), and redundant stock or working insecticidal solutions. The washing of Long-Lasting Insecticidal Nets (LLINs) during preparation for laboratory and experimental hut trials also contribute to wastewater with insecticide content. Human and environmental exposure to insecticidal waste can occur during transport, categorization, storage, and disposal, resulting in environmental pollution and potential health effects. Various national and international guidelines have been devised for safe disposal and should be strictly followed to avoid adverse effects on humans or environment. To facilitate proper insecticidal waste management, this paper outlines simple but safe practices derived from international and national guidelines that can be adopted by other similar facilities. National and international policies related to chemical management were reviewed and translated into Standard Operating Procedures (SOPs), training pathways, and manuals. National Environmental Management Council (NEMC) assessed the test facility and recommended disposal procedures. NEMC recommendations were followed to construct the soak pits for liquid waste disposal while chemical transporters and incinerators were contracted for solid waste disposal. An environmental expert was contracted for environmental audit and annual monitoring. Studies and activities at the facility were evaluated for their waste generation index. Safety manual and SOPs on risk assessment, waste management and disposal, handling hazardous materials, health and safety procedures, and chemical usage were written. At KCMUCo-PAMVERC, an annual average of 0.02 and 24.9 cubic meters of liquid waste, which mainly includes a mixture of water, insecticides, and solvents, were generated from laboratory experiments (phase I) and semi-field LLIN experiments (phase II), respectively, while the IRS semi-field experiments generated an annual average of 88 L of liquid waste and 6.3 tons of solid waste. An annual average of 0.18 cubic meters of liquid waste results from other sources, including expired laboratory reagents. Well-translated national and international policies/regulations may be adopted by insecticide test facilities for proper and effective waste disposal.
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