Comparison of cone bioassay estimates at two laboratories with different Anopheles mosquitoes for quality assurance of pyrethroid insecticide-treated nets

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dc.creatorMbwambo, Stephen
dc.creatorBubun, Nakei
dc.creatorMbuba, Emmanuel
dc.creatorMoore, Jason
dc.creatorMbina, Kasiani
dc.creatorKamande, Dismas
dc.creatorLaman, Moses
dc.creatorMpolya, Emmanuel
dc.creatorOdufuwa, Olukayode
dc.creatorFreeman, Tim
dc.creatorKarl, Stephan
dc.creatorMoore, Sarah
dc.date2022-08-24T12:51:04Z
dc.date2022-08-24T12:51:04Z
dc.date2022-07-07
dc.date.accessioned2022-10-25T09:20:38Z
dc.date.available2022-10-25T09:20:38Z
dc.descriptionThis research article was published by Springer Nature, 2022
dc.descriptionckground: Quality assurance (QA) of insecticide-treated nets (ITNs) delivered to malaria-endemic countries is con ducted by measuring physiochemical parameters, but not bioefcacy against malaria mosquitoes. This study explored utility of cone bioassays for pre-delivery QA of pyrethroid ITNs to test the assumption that cone bioassays are consist ent across locations, mosquito strains, and laboratories. Methods: Double-blinded bioassays were conducted on twenty unused pyrethroid ITNs of 4 brands (100 nets, 5 subsamples per net) that had been delivered for mass distribution in Papua New Guinea (PNG) having passed pre delivery inspections. Cone bioassays were performed on the same net pieces following World Health Organization (WHO) guidelines at the PNG Institute of Medical Research (PNGIMR) using pyrethroid susceptible Anopheles farauti sensu stricto (s.s.) and at Ifakara Health Institute (IHI), Tanzania using pyrethroid susceptible Anopheles gambiae s.s. Additionally, WHO tunnel tests were conducted at IHI on ITNs that did not meet cone bioefcacy thresholds. Results from IHI and PNGIMR were compared using Spearman’s Rank correlation, Bland–Altman (BA) analysis and analysis of agreement. Literature review on the use of cone bioassays for unused pyrethroid ITNs testing was conducted. Results: In cone bioassays, 13/20 nets (65%) at IHI and 8/20 (40%) at PNGIMR met WHO bioefcacy criteria. All nets met WHO bioefcacy criteria on combined cone/tunnel tests at IHI. Results from IHI and PNGIMR correlated on 60-min knockdown (KD60) (rs=0.6,p=0.002,n=20) and 24-h mortality (M24) (rs=0.9,p<0.0001,n=20) but BA showed systematic bias between the results. Of the 5 nets with discrepant result between IHI and PNGIMR, three had confdence intervals overlapping the 80% mortality threshold, with averages within 1–3% of the threshold. Including these as a pass, the agreement between the results to predict ITN failure was good with kappa=0.79 (0.53–1.00) and 90% accuracy. Conclusions: Based on these study fndings, the WHO cone bioassay is a reproducible bioassay for ITNs with>80% M24, and for all ITNs provided inherent stochastic variation and systematic bias are accounted for. The literature
dc.formatapplication/pdf
dc.identifierhttps://doi.org/10.1186/s12936-022-04217-3
dc.identifierhttps://dspace.nm-aist.ac.tz/handle/20.500.12479/1490
dc.identifier.urihttp://hdl.handle.net/123456789/95102
dc.languageen
dc.publisherSpringer Nature.
dc.subjectBioefficacy
dc.subjectBioassay
dc.subjectCone bioassay
dc.subjectTunnel test Insecticide treated nets
dc.subjectLong lasting insecticidal nets
dc.subjectPyrethroid
dc.subjectMosquito
dc.subjectAnopheles
dc.subjectMalaria
dc.titleComparison of cone bioassay estimates at two laboratories with different Anopheles mosquitoes for quality assurance of pyrethroid insecticide-treated nets
dc.typeArticle

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