Despite the highest global burden of malaria, information on bionomics and insecticide resistance status of malaria vectors is grossly lacking in the densely populated Sahelo-Sudanian region of Nigeria. To support evidence-based vector control we characterised transmission and resistance profiles of Anopheles coluzzii populations from three sites in northern Nigeria. High sporozoite infection (~19.51%) was found in the An . coluzzii populations. A high pyrethroid resistance was observed with only 1% mortality against deltamethrin, a high LD 50 (96.57 µg/ml), and a high LT 50 (170.27 min, resistance ratio of ~51 compared with the fully susceptible Ngoussou colony). Moderate carbamate resistance was observed. Synergist bioassays significantly recovered deltamethrin susceptibility implicating CYP450s (mortality = 85%, χ 2 = 134.04, p < 0.0001) and esterases (mortality = 56%, χ 2 = 47.31, p < 0.0001). Reduced bed net efficacy was also observed, with mortalities on exposure to the roof of PermaNet3.0 (PBO + deltamethrin) more than 22 times compared to the side panel (deltamethrin). TaqMan genotyping revealed a high frequency of 1014F kdr mutation (82%) with significant difference in genotype distribution associated with permethrin resistance [OR = 4.69 (CI:1.53–14.35, χ 2 = 8.22 p = 0.004]. Sequencing of exons 18–21 of the VGSC led to detection of two additional nonsynonymous mutations, Ile10148Asn and Ser1156Gly. These findings highlight the threats posed by the highly resistant An . coluzzii to malaria control in Nigeria.

Mosquitoes are tiny insects that can serve as vectors for numerous infectious diseases like malaria. Malaria is considered as one of the major causes of mortality, loss of productivity and a major contributor of poverty in the African continent. In 2020, most global malaria cases (94%) were recorded in the Africa Region. In Nigeria, about 97% of the estimated populations are at risk of malaria, with up to 27% and 24% of Africa and global malaria deaths respectively in 2018. Malaria control programmes in Africa have challenge of rising insecticide resistance in the main anopheline vectors, this affects primary malaria vector control interventions. In Africa, the dominant mosquito species that transmit malaria parasites are mainly Anopheles gambiae s.s. A key control strategy against major mosquito- borne diseases involves targeting mosquito vectors to disrupt the transmission of diseases. Environmental changes can alter the genetic structure, protein profiles and enzymes of mosquitoes leading to increase in insecticide resistance. Knowing the ecology, spatial distribution of mosquito larvae, and some environmental features like physicochemical factors are important in tackling insecticide resistance. Water and larval samples were collected from three Anopheles mosquito breeding sites in August, September and October, 2019. Physicochemical parameters, larval densities and morphological specie identifications were determined. Results from this study reveal variation in levels of each studied parameter according to the site of the study. These variations can be attributed to differences in activities that occur in each site of the study.. Correlation studies indicated a significantly higher larval density in agricultural site relative to industrial and residential sites, this was by a magnitude of 10.65 and 41.30 respectively. Anopheles gambiae s.s. complex was found to be predominant in all the three study sites. These physicochemical parameters can either have negative or positive effect on mosquito biology depending on their levels, hence can affect vector control measures making it significant in terms of vector control programmes.

The effectiveness of alkaline hydrogen peroxide as a suitable choice of pretreatment for the conversion of millet husk to reducing sugars using cellulase enzyme for hydrolysis and subsequent ethanol production was determined. The effects of three variables on reducing sugar production from millet husk were determined using one factor at a time (OFAT) method namely; peroxide concentration, pretreatment time and pretreatment temperature. From the results, it was observed that a significant (P<0.05) amount of reducing sugars were lost during pretreatment of millet husk. The untreated group which was only physically pretreated (milled) however yielded a significantly higher (P<0.05) reducing sugar concentration of 10.67mg/ml after enzymatic hydrolysis while the highest reducing sugar concentration of 4.82mg/ml was obtained using 0.375%v/v peroxide concentration for 60minutes at 250C. Therefore, pretreatment of biomass with alkaline hydrogen peroxide may be more suitable for feedstock with high lignin contents than millet husk.