Malaria Journal (Oct 2019)

Bio-efficacy and wash resistance of MAGNet long-lasting insecticidal net against wild populations of Anopheles funestus in experimental huts in Muheza, Tanzania

  • Eliningaya J. Kweka,
  • Patrick K. Tungu,
  • Aneth M. Mahande,
  • Humphrey D. Mazigo,
  • Subira Sayumwe,
  • Shandala Msangi,
  • Lucile Lyaruu,
  • John Waweru,
  • William Kisinza,
  • James Wangai

DOI
https://doi.org/10.1186/s12936-019-2973-x
Journal volume & issue
Vol. 18, no. 1
pp. 1 – 8

Abstract

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Abstract Background The decline in malaria cases and vectors is major milestone in fighting against malaria. The efficacy of MAGNet long-lasting insecticidal nets (MAGNet LLIN), an alpha-cypermethrin incorporated long-lasting net, with the target dose ± 25% of 5.8 g active ingredient (AI)/kg (4.35–7.25 g AI/kg) was evaluated in six veranda-trap experimental huts in Muheza, Tanzania against freely flying wild population of Anopheles funestus. Methods MAGNet LLINs were tested against wild, free-flying, host-seeking An. funestus mosquitoes over a period of 6 weeks (total of 36 nights in the huts). MAGNet LLIN efficacy was determined in terms of mosquito mortality, blood-feeding inhibition, deterrence, induced exiting, personal protection, and insecticidal killing over 20 washes according to WHO standardized procedures. Efficacy was compared with reference to a WHOPES recommended approved LLINs (DuraNet) and to a net conventionally treated (CTN) treated with alpha-cypermethrin at WHO-recommended dose and washed to just before cut-off point. The efficacy of MAGNet was evaluated in experimental huts against wild, free-flying, pyrethroid-resistant An. funestus. The WHO-susceptibility method was used to detect resistance in wild Anopheles exposed to 0.75% permethrin. Mosquito mortality, blood-feeding inhibition and personal protection were compared between untreated nets and standard LLINs. Blood-feeding rates were recorded and compared between the 20 times washed; blood-feeding rates between 20 times washed MAGNet LLIN and 20 times washed WHOPES-approved piperonyl butoxide (PBO)/pyrethroid were not statistically different (p > 0.05). Results The results have evidently shown that MAGNet LLIN provides similar blood-feeding inhibition, exophily, mortality, and deterrence to the standard approved LLIN, thus meeting the WHOPES criteria for blood feeding. The significantly high feeding inhibition and personal protection over pyrethroid-resistant An. funestus recorded by both unwashed and 20 times washed MAGNet compared to the unwashed DuraNet, the WHOPES-approved standard pyrethroid-only LLIN provides proof of MAGNet meeting Phase II WHOPES criteria for a LLIN. Conclusion Based on this study, MAGNet has been shown to have a promising impact on protection when 20 times washed against a highly resistant population of An. funestus.

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