Studies implemented to evaluate the success of Long-lasting insecticidal nets (LLIN) distribution campaigns are often limited to ownership and utilization rates, neglecting other factors that directly affect the efficacy of the tool in malaria control. This study investigates sleeping habits and net maintenance behaviour in addition to LLIN ownership, utilization and the challenges associated with LLIN use among residents in Ilorin City where the tool has been massively distributed.

Objective: To examine malaria-related knowledge and practices among residents in Ilorin City\ud to guide forthcoming malaria elimination action of the recently restructured Nigerian National\ud Malaria Elimination Program.\ud Methods: Community-wide cross-sectional study was conducted in June 2012 using pretested\ud structured questionnaire and interview schedule to collect information on perception, prevention\ud and treatment of malaria among the residents.\ud Results: Majority of the respondents attributed malaria to mosquito bites and prevented the\ud disease through multiple means including the use of long-lasting insecticidal nets (60%),\ud insecticide sprays (54%) and mosquito coils (48%) alternatively. All the respondents spraying\ud insecticides in the bedrooms shortly before bed time stayed outdoors during night hours. Fifty\ud three percent of the respondents treated the last malaria episode at the hospital/clinic, and the\ud remaining (47%) employed self-medication. Only 6.1% of those who engaged in self-medication\ud used artemisinin combination therapy drugs.\ud Conclusions: Combined use of long-lasting insecticidal nets and insecticide sprays call for\ud investigation of behavioural and physiological insecticide resistance in the mosquitoes present in\ud this area. Night time outdoor staying behaviour mandated by spraying of insecticides and possible\ud switch of the vectors to bite outdoor at early night hour also necessitate incorporation of outdoor\ud mosquito control into the malaria elimination plan for this locality. Likewise, observation of selfmedication in spite of high literacy levels implies that campaigns against such practice may not\ud yield the desired result unless quality healthcare service is made affordable and accessible to all

In Nigeria, most research and malaria vector control efforts have focused on primary vectors within the Anopheles gambiae complex, with less emphasis on other secondary vectors. Consequently, understudied secondary vectors have demonstrated a proportional and increasing role in transmission. This study utilized geospatial models to understand the potential distribution of anopheline species other than An. gambiae complex (non-gambiae species) in Nigeria. Adult mosquitoes were sampled monthly between 2020 and 2022, with concurrent surveys of larval sites in selected Local Government Areas (LGAs) across 20 States resulting in the collection and identification of over 100,000 Anopheline mosquitoes. Utilizing 23 environmental variables, the model produced maps depicting the potential geographical distribution of four secondary vector species under current climatic conditions. An. funestus, An. coustani, An. maculipalpis, and An. rufipes dominated collections, with other species also present. Most species collected exhibited higher occurrences in the Northern parts of the country, albeit with lower numbers, while they seem confined to fewer locations in the southern parts - with higher densities. An. funestus, An. maculipalpis, and An. rufipes demonstrated a higher potential for wide range expansion compared to An. coustani based on the model. Overall, modeling outputs indicate that non-An. gambiae were expected to exhibit a wide-spread across the country, with their distribution primarily influenced by temperature rather than precipitation-related factors. These models provide research scientists and decision-makers with a baseline for research, monitoring towards establishing management plans for future national mosquito surveillance and control programs in Nigeria.

Malaria vector surveillance is required to determine disease transmission dynamics, vector insecticide susceptibility status, suitable control strategies and impact of control interventions. However, capacity and resources for vector surveillance and insecticide resistance monitoring is often inadequate in most countries at risk of vector-borne diseases. Collaborations and linkages between malaria control policy makers and existing research institutions generating vector surveillance research data are often weak, thereby hindering the availability of data for decision-making. A national vector surveillance programme, mobilizing all stakeholders towards quality data generation and policy making, is required for effective data-driven country-wide vector control. This paper provides an analysis and suggested future directions for such synergized national malaria vector surveillance and insecticide resistance monitoring system currently being implemented by all research and policy stakeholders in Nigeria. The harmonized national vector surveillance system described here can be used as a model for the development or improvement of such structures in other countries with high malaria transmission risks.

Indoor resting mosquitoes were collected between November 2013 and May 2014 using Pyrethrum spray collection (PSC). The mosquitoes were identified using morphological keys and species specific polymerase chain reaction (PCR) assays. The species composition of members of the An. gambiae complex and reported malaria cases in the selected study communities were spatially mapped using Arc GIS software. A total of 645 mosquitoes were collected from the study sites and morphologically identified. This comprised of 598 (92%) Anopheles species, 42 (7%) Culex species and 5 (1%) Aedes species. One hundredand ninety-six An. gambiaes. l. samples were randomly selected and successfully identified by PCR. The composition of the mosquitoes species collected in Gaa Bolohunduro showed that a higher proportion 53 (64.6%) were An. arabiensis compared to lower proportions 5(6.1%) of An. coluzzii and 24 (29.3%) An. gambiae. In Osin, only 12 (10.5%) were An. arabiensis compared to 13 (11.4%) and 89 (78.1%) identified as An. coluzzii and An. gambiae respectively. The variation in the composition of members of the An. gambiaes. l. identified in Gaa Bolohunduro was not significant (p=0.070) compared to Osin (p=0.043). A weak correlation coefficient showed that the predominance of Anopheles in both communities was not dependent on rainfall, though variation in the members of the complex within the wet and dry season was significant (p<0.01). The sympatric occurrence and availability of An. gambiaes. s. and An. arabiensis during the dry and wet seasons corroborated the high malaria prevalence identified in Ilorin South. This suggests that both vectors will sustain malaria transmission in the study sites. Hence, a vector control strategy in these localities should be informed by the individual behaviour of each vector species identified. Keywords: Anopheles arabiensis, Anopheles coluzzi, Anopheles gambiae, distribution, composition, malaria case

Effectiveness of currently deployed insecticide-based malaria vector control measures depends on continuous insecticide resistance monitoring and management. Urban malaria is becoming a serious health problem in Africa partly due to vector resistance in urban areas. To provide insecticide resistance trends information for effective resistance management, this study assessed insecticide susceptibility status and occurrence of knock down resistance mutation in Anopheles mosquitoes from urban Ilorin, Nigeria in two different years. Malaria vectors in urban Ilorin were assayed for susceptibility to WHO-recommended insecticides in 2017 and 2020 using WHO test kits. Sub-sets of exposed An. gambiae s.l. mosquitoes were PCR-assayed for sibling species and knock down resistance (kdr) mutation detection. Full mosquito susceptibility (98–100% mortality; Niger and Baruba) and suspected resistance (95–97% mortality; Shao garage and Edun) to alphacypermethrin were recorded in 2017. Significantly (p ≤ 0.010) reduced mosquito mortalities indicating increased alphacypermethrin resistance were recorded in 2020. Permethrin, lambda-cyhalothrin and DDT resistance increased significantly (p ≤ 0.03) from 2017 (42–89%) to 2020 (5.8–58%) but not deltamethrin (p ≥ 0.086). Mosquitoes tested were mostly susceptible to bendiocarb and pirimiphos-methyl. The kdr-L995F detected increased from 15 to 20% for An. arabiensis, 24–36% for An. gambiae and 0–18% for An. coluzzii from 2017 to 2020. For both 2017 and 2020, most of the pyrethroid resistant (≥ 80%) and susceptible (≥ 75%) mosquitoes from each site were identified as An. arabiensis. This study presents a first report on widespread occurrence of kdr-L995F mutation in An. arabiensis mosquito populations in urban Ilorin, Kwara State, Nigeria. The report of pyrethroid-resistant An. arabiensis prevalence in urban Ilorin triggered the switch from pyrethroid only to dual active ingredient ITN distribution in the city since 2020. Extension of dry season periods due to climate change may drive more preponderance of An. arabiensis in the study area. Therefore, the implementation of supplementary vector control measures targeted at An. arabiensis is required in this locality.