Efficacy of Olyset Duo, a bednet containing pyriproxyfen and permethrin, versus a permethrin-only net against clinical malaria in an area with highly pyrethroid-resistant vectors in rural Burkina Faso: a cluster-randomised controlled trial

Abstract

EU Seventh Framework Programme.

The effectiveness of older insecticide-treated bed nets (ITNs) to prevent malaria infection in an area of moderate pyrethroid resistance: results from a cohort study in Malawi

“…However, a recent study in an area of high oxidase-based pyrethroid resistance in Mozambique found complete loss of An. funestus susceptibility following exposure to permethrin or deltamethrin that was only moderately restored after pre-exposure to PBO [46] suggesting that other next-generation ITNs incorporating chlorfenapyr [47] or pyriproxyfen [48] might be needed in settings of high pyrethroid resistance. In Malawi, Centers for Disease Control and Prevention bottle bioassays indicated that An.…”

“…Although potential confounders were carefully ascertained and adjusted for in analyses, it is possible that residual and/or unmeasured confounding (due to heterogeneity in insecticide resistance, condition of ITNs, and insecticide content) could have biased the findings of this observational study. While several observational studies have found limited impact of pyrethroid resistance on the effectiveness of ITNs [5][6][7][8][9], studies comparing PBO [44] or dual-treated ITNs [48] to pyrethroid-only ITNs have demonstrated a clear benefit of these nets over pyrethroid-only ITNs in cluster-randomized designs, suggesting that some of the protection, such as through the community effect, may be underestimated in observational studies of the impact of resistance on ITNs. Additionally, the measurement of the physical integrity of ITNs was imperfect since caregiver self-report may be subject to recall and social desirability biases and assessing the presence or absence of holes of varying size does not capture other forms of net deterioration (e.g.…”

Preferred resting surfaces of dominant malaria vectors inside different house types in rural south-eastern Tanzania

“…To counter the growing challenge of insecticide resistance [29], most countries have switched from using pyrethroids, and now rely mostly on organophosphates or carbamates, as well as some new insecticide classes such as neonicotinoids, which were recently introduced [30]. There have also been calls to introduce bed nets with multiple active ingredients or synergists as a way to tackle resistance [31][32][33].…”

Steroid hormone agonists reduce female fitness in insecticide-resistant Anopheles populations

“…The public health value of incorporating insect growth regulators into LLINs has been previously demonstrated in a clinical trial of a PPF permethrin net from Sumitomo Chemical Ltd (Tiono et al, 2018). This trial, conducted in an area of intense malaria transmission and highly pyrethroid resistant vectors, found that malaria incidence was reduced in clusters using PPF-permethrin nets compared to standard LLINs.…”

“…To restore the efficacy of pyrethroid treated bed nets in areas with resistant vectors, next generation nets impregnated with both pyrethroid insecticides and the cytochrome p450 inhibitor piperonyl butoxide (PBO) (Protopopoff et al, 2018) are now being implemented in several African countries. In addition, dual action nets with pyrethroids plus the sterilising compound pyriproxyfen have been successfully trialled in a field settings (Bayili et al, 2017;Protopopoff et al, 2018;Tiono et al, 2018) and this class of nets are expected to be in field use by the end of 2020. Mathematical models demonstrate that these new classes of nets could play a key role in reducing malaria cases in areas with high levels of insecticide resistance (Churcher et al, 2016).…”