Utilization of vector bionomics, remote sensing and larval habitat characterization data to inform larval source management decision in the high malaria burden state of Kebbi, Nigeria

(2025) 24:370 Oduola et al. Malaria Journal https://doi.org/10.1186/s12936-025-05568-3 Malaria Journal Open Access RESEARCH Utilization of vector bionomics, remote sensing and larval habitat characterization data to inform larval source management decision in the high malaria burden state of Kebbi, Nigeria Adedayo O. Oduola1*, Petrus U. Inyama1, Lazarus M. Samdi1, Muhammad A. Bunza2, Abubakar Bagudu3, Ifeanyi Okeke1, Grace Yina1, Mary Esema4, Godwin Ntadom4, Kelley Ambrose5, Jules Mihigo6, Melissa Yoshimizu7 and Aklilu Seyoum5 Abstract Background Malaria remains a public health challenge with Nigeria having the highest burden in cases and deaths worldwide. Increased outdoor and indoor biting of Anopheles gambiae sensu lato (s.l.) and large gaps in protection have become emerging challenges threatening malaria control efforts in Kebbi State, Nigeria. This study provided data on vector behaviour, the distribution, diversity, and other characteristics of larval habitats to inform the feasibility of larval source management in the state. Methods Routine entomological data were comparatively analyzed across six entomological monitoring sites located in Akwa Ibom, Ebonyi, Kebbi, Oyo, Plateau and Sokoto states in Nigeria. With a focus on Kebbi State, using Geographical Information System (GIS) data integrated with satellite imagery, potential larval habitats were remotely identified, characterized and mapped in Argungu, Bunza and Kalgo local government areas (LGAs). Field data on larval habitat abundance, larval density, and proximity of larval habitats to human habitation, and breeding index were determined and analyzed. Results Anopheles gambiae s.l. was the predominant 13,201(100%) malaria vector species in Kebbi State, in contrast to other states where Anopheles coustani, Anopheles funestus s.l., Anopheles maculipalpis, Anopheles marshallii group, Anopheles moucheti, Anopheles pharoensis and Anopheles rufipes were also collected. The average human biting rate of An. gambiae s.l. in Kebbi was the highest at both indoors and outdoors in the dry (15.2, 8.7 b/p/n) and rainy (42.2, 14.3 b/p/n) seasons across the six routine surveillance sites. The human behavioural observation data in Kebbi showed a protection gap of 0.83 (83%) from mosquito bite exposures both indoors and outdoors. A total of 3218 and 635 potential mosquito larval habitats were sampled by the field enumerators and sample collectors respectively across Argungu, Bunza and Kalgo LGAs. Of the 635 potential larval habitats identified by sample collectors, 460 (97.9%) were positive for Anopheles larvae. Eleven different larval habitat types were identified including temporary and permanent habitats. The proportion of temporary larval habitats within 100 m proximity of inhabited houses *Correspondence: Adedayo O. Oduola Full list of author information is available at the end of the article © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/. Oduola et al. Malaria Journal (2025) 24:370 Page 2 of 16 was highest in Argungu LGA 464 (43%) Bunza 230 (18%), and Kalgo 276 (61%). The highest proportions of those habitats were rice fields in Argungu 231 (80%), Bunza 446 (96%) and Kalgo 90 (94%). Conclusion The consistently high entomology indices, measured protection gaps, productive and abundant larval habitats situated near human habitations throughout the year indicate the need for complementary vector control interventions, such as larval source management (LSM) in Kebbi State. Keywords Larval source management, Kebbi, Malaria vectors, Nigeria, Remote sensing, GIS, Mapping, Habitat characterization Background Malaria remains a major public health challenge and is the leading cause of morbidity and mortality in Nigeria [1]. According to the World Malaria Report, there were 249 million cases globally in 85 malaria endemic countries in 2023. Nigeria was first among the 29 countries accounting for 95% of the global cases, and first (at 31.1%) among the four countries accounting for nearly half of all malaria deaths worldwide in 2022 [2]. Nigeria, with malaria cases estimated at 68 million and deaths from malaria at 194,000 in 2022 [1], has been identified as one of 11 high burdens to high impact countries. Between 2019 and 2022, there was an increase of about 5.3 million estimated cases in the country [2]. Out of 36 states and the Federal Capital Territory, Kebbi State contributed an estimated 3.1% of the 68 million malaria cases in 2021, and children under 5 years accounted for 49% of the cases. This makes Kebbi the state with the highest malaria burden in Nigeria [3, 4]. Malaria burden is driven by multiple factors ranging from socioeconomic to ecological. Ecologically, rice fields have been reported as major contributors to the proliferation of competent malaria vector species in countries with high malaria transmission [5–7] including Nigeria. Leading rice producing areas in Nigeria are Kebbi (the major producer in northern Nigeria), Borno, Kano, and Kaduna [8, 9] states. Kebbi State has several hectares of fadama (Hausa for “irrigable lowland”) farming stretching across 15 out of the 21 local government areas (LGAs) in the state, and rice farming has become a mainstream commercial activity, reducing the need for importation [9]. Traditional rain-fed rice farming in Kebbi has been driven by rainfall and suitable ‘tableland’ topography, which encourages water retention. The access of small holder farmers to the government’s Anchors Borrowers Programme, an initiative to support the production of agricultural commodities such as rice, maize, sugarcane and wheat, has further increased farmer incomes due to multiple rice harvests in the year, made possible through irrigation [10, 11]. Rice fields now are flooded by rain during the rainy season and irrigated via other water sources such as solar/fuel-powered boreholes during the dry season [12]. These newer irrigation practices create and maintain mosquito larval habitats in drier months, wh (...truncated)