Kipsum, M. | bioRxiv Science

bioRxiv2026

The evaluation of the SumiOne™ spatial emanators against wild Anopheles funestus in experimental huts in Siaya County, western Kenya

Background Spatial Emanators (SEs) are a promising tool for complementing existing malaria vector control interventions. In 2025, the World Health Organization (WHO) issued a conditional recommendation for SEs, and two transfluthrin-based products were added to the WHO Prequalification List. As SEs are scaled up, additional products are needed to ensure reliable supply, competitive pricing, and continued innovation. Methods This study evaluated the efficacy of SumiOne SE, containing 10% metofluthrin, in experimental huts in Siaya County, western Kenya. SumiOne SE efficacy was evaluated in six experimental huts, three intervention and three control, using human landing catches (HLCs) and aspiration. Collections were conducted in two 12-night phases, alternating between HLC and aspiration every six nights. Outcomes included reductions in human landing rates, density, exophily and blood feeding inhibition of Anopheles mosquitoes. Results SumiOne SE significantly reduced indoor densities of An. funestus with 63% protective effect (IRR = 0.37, 95% CI: 0.20-0.69, p = 0.0087). Overall An. funestus density (indoor and outdoor combined) was reduced by 58% (IRR=0.42, 95% CI: 0.22-0.79; p=0.0222). The rate of exophily of An. funestus exiting was 34% (95% CI: 27-42) in the intervention huts compared to 2% (95% CI: 1-4) in the control huts (p< 0.0001). Blood feeding inhibition for An. funestus was 46% with 44% (95% CI: 36-51) of the collected mosquitoes being blood fed in the intervention huts compared to 81% (95% CI: 76-86) blood fed in the control huts, (p<0.0001). Conclusion These findings support SumiOne SEs potential as a complementary vector control tool, alongside existing core interventions such as Insecticide Treated Nets and Indoor Residual Spraying, particularly in contexts where additional protection is needed.

zoology↗

bioRxiv2020

Western Kenyan Anopheles gambiae s.s. showing intense permethrin resistance harbor distinct microbiota

BackgroundInsecticide resistance poses a growing challenge to malaria vector control in Kenya and around the world. Following evidence of associations between the mosquito microbiota and insecticide resistance, we comparatively characterized the microbiota of An. gambiae s.s. from Tulukuyi village, Bungoma, Kenya, with differing permethrin resistance profiles. MethodsUsing the CDC bottle bioassay, 133 2-3 day-old, virgin, non-blood fed female F1 progeny of field-caught An. gambiae s.s. were exposed to five times (107.5g/ml) the discriminating dose of permethrin. Post bioassay, 50 resistant and 50 susceptible mosquitoes were subsequently screened for kdr East and West mutations, and individually processed for microbial analysis using high throughput sequencing targeting the universal bacterial and archaeal 16S rRNA gene. Results47% of the samples tested (n=133) were resistant, and of the 100 selected for further processing, 99% were positive for kdr East and 1% for kdr West. Overall, 84 bacterial taxa were detected across all mosquito samples, with 36 of these shared between resistant and susceptible mosquitoes. A total of 20 were unique to the resistant mosquitoes and 28 were unique to the susceptible mosquitoes. There were significant differences in bacterial composition between resistant and susceptible individuals (F=2.33, P=0.001), with presence of Sphingobacterium, Lysinibacillus and Streptococcus (all known pyrethroid-degrading taxa), and the radiotolerant Rubrobacter, being significantly associated with resistant mosquitoes. On the other hand, the presence of Myxococcus, was significantly associated with susceptible mosquitoes. ConclusionThis is the first report of distinct microbiota in An. gambiae s.s. associated with intense pyrethroid resistance. The findings highlight differentially abundant bacterial taxa between resistant and susceptible mosquitoes, and further suggest a microbe-mediated mechanism of insecticide resistance in mosquitoes. Our results also indicate fixation of the kdr East mutation in this mosquito population, precluding further analysis of its associations with the mosquito microbiota, but presenting the hypothesis that any microbe-mediated mechanism of insecticide resistance would be likely of a metabolic nature. Overall, this study lays initial groundwork for understanding microbe-mediated mechanisms of insecticide resistance in African malaria vectors, and potentially identifying novel microbial markers of insecticide resistance that could supplement existing vector surveillance tools.

molecular biology↗