Author:
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Glunt, Katey D.; Coetzee, Maureen; Huijben, Silvie; Koffi, A. Alphonsine; Lynch, Penelope A.; N'Guessan, Raphael; Oumbouke, Welbeck A.; Sternberg, Eleanore D.; Thomas, Matthew B.
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Abstract:
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In spite of widespread insecticide resistance in vector
mosquitoes throughout Africa, there is limited evidence that
long-lasting insecticidal bed nets (LLINs) are failing to
protect against malaria. Here, we showed that LLIN contact in
the course of host-seeking resulted in higher mortality of
resistant Anopheles spp. mosquitoes than predicted from standard
laboratory exposures with the same net. We also found that
sublethal contact with an LLIN caused a reduction in blood
feeding and subsequent host-seeking success in multiple lines of
resistant mosquitoes from the laboratory and the field. Using a
transmission model, we showed that when these LLIN-related
lethal and sublethal effects were accrued over mosquito
lifetimes, they greatly reduced the impact of resistance on
malaria transmission potential under conditions of high net
coverage. If coverage falls, the epidemiological impact is far
more pronounced. Similarly, if the intensity of resistance
intensifies, the loss of malaria control increases nonlinearly.
Our findings help explain why insecticide resistance has not yet
led to wide-scale failure of LLINs, but reinforce the call for
alternative control tools and informed resistance management
strategies. |