Indoor Resting Density and Man-Biting Rate of Anopheles gambiae s.l. in Relation to Ownership of Insecticidal Treated Bed Nets in Nembe Local Government Area, Bayelsa State, Nigeria

Indoor resting density and biting activity of malaria vectors, together with household ownership of insecticidal treated bed nets (ITBN), are important indicators for evaluating malaria control interventions. This study assessed indoor resting density, man-biting rate, and ITBN ownership in selected communities of Nembe Local Government Area, Bayelsa State, Nigeria. Adult mosquitoes were collected using pyrethroid spray catch methods, and ITBN ownership was assessed through structured questionnaires. A total of 290 mosquitoes were collected, comprising 192 (66.2%) Anopheles gambiae sensu lato and 98 (33.8%) Culex quinquefasciatus. Female An. gambiae were predominantly unfed (46.7%) and gravid (27.2%). The mean indoor resting density and man-biting rate were 16 mosquitoes per room per night and 21.4 bites per person per night, respectively, with significant variation across communities (p < 0.05). Of the 904 households surveyed, 45.0% owned ITBN. Among owners, 88.9% reported consistent use, while 10.6% used nets irregularly. Community-level analysis showed significant associations between ITBN ownership and use patterns and indoor resting density (r = 0.83, p < 0.05) and estimated man-biting rate (r = 0.78, p < 0.05). Irregular ITBN use was strongly associated with higher biting rates (r = 0.86, p < 0.05). These findings indicate sustained indoor malaria transmission risk associated with high vector density, moderate ITBN coverage, and inconsistent utilization, highlighting the need for improved ITBN use and integrated vector control strategies in the study area.