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Managing insecticide resistance in malaria vectors in Africa: case studies from Cameroon, Côte d'Ivoire and Tanzania.

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Title: Managing insecticide resistance in malaria vectors in Africa: case studies from Cameroon, Côte d'Ivoire and Tanzania.
Authors: Tabue RN; National Malaria Control Programme, Yaoundé, Cameroon., Gbalegba CGN; National Malaria Control Programme, Abidjan, Côte d'Ivoire., Mwalimu CD; National Malaria Control Programme, Dodoma, United Republic of Tanzania., Tungu PK; National Institute for Medical Research, Amani, United Republic of Tanzania., Fodjo BK; Centre Suisse de Recherches Scientifiques en Côte D'Ivoire, Abidjan, Côte d'Ivoire.; Unité de Formation et de Recherche des Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d'Ivoire., Elanga-Ndille E; Centre for Research Into Infectious Diseases, Yaoundé, Cameroon.; Vector-Borne Diseases Laboratory of the Biology and Applied Ecology Research Unit, Department of Animal Biology, Faculty of Sciences, University of Dschang, Dschang, Cameroon., Menze B; Centre for Research Into Infectious Diseases, Yaoundé, Cameroon., Mosha J; National Institute for Medical Research, Mwanza, United Republic of Tanzania., Wolie RZ; Unité de Formation et de Recherche des Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d'Ivoire.; Vector Control Product Evaluation Centre - Institut Pierre Richet (VCPEC-IPR), Bouaké, Côte d'Ivoire., Clarke SE; London School of Hygiene & Tropical Medicine, London, UK., Lines J; London School of Hygiene & Tropical Medicine, London, UK., Abeku TA; Malaria Consortium, London, UK. t.abeku@malariaconsortium.org.
Source: Malaria journal [Malar J] 2025 Nov 05; Vol. 24 (1), pp. 375. Date of Electronic Publication: 2025 Nov 05.
Publication Type: Journal Article
Language: English
Journal Info: Publisher: BioMed Central Country of Publication: England NLM ID: 101139802 Publication Model: Electronic Cited Medium: Internet ISSN: 1475-2875 (Electronic) Linking ISSN: 14752875 NLM ISO Abbreviation: Malar J Subsets: MEDLINE
Imprint Name(s): Original Publication: London : BioMed Central, [2002-
MeSH Terms: Insecticide Resistance* , Mosquito Control*/methods , Mosquito Vectors*/drug effects , Malaria*/prevention & control , Insecticides*/pharmacology , Anopheles*/drug effects, Tanzania ; Cote d'Ivoire ; Cameroon ; Animals ; Humans ; Insecticide-Treated Bednets
Abstract: Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: All the authors approved the final version of the manuscript for publication. Competing interests: The authors declare no competing interests.
Background: Malaria remains a significant public health challenge in sub-Saharan Africa (SSA), where vector control strategies, particularly insecticide-treated nets (ITNs) and indoor residual spraying (IRS), have played a critical role in reducing transmission. However, the emergence and spread of insecticide resistance among malaria vectors threatens to undermine these gains. In response, many countries in the region have developed national insecticide resistance management (IRM) plans. This study evaluates the adequacy and implementation of these plans in Cameroon, Côte d'Ivoire, and mainland Tanzania, aiming to identify key challenges and best practices, and to develop actionable recommendations applicable to these and other countries with similar contexts.
Methods: A mixed-methods approach was employed, incorporating document reviews, epidemiological and entomological data analysis, and discussions with stakeholders and experts in 2023. The evaluation focused on the alignment of national IRM plans with national malaria control strategies, their operational effectiveness, and the ability to guide effective monitoring and management of insecticide resistance. The assessment was conducted before changes in the global aid funding landscape.
Results: Each country has developed a 5-year IRM plan; however, the plans for Côte d'Ivoire and mainland Tanzania were found to be outdated. While the plans align well with national malaria strategies and international guidelines, implementation has been hindered by inadequate domestic funding and heavy reliance on external donors. Sentinel site coverage for resistance monitoring remains limited, though ITN campaigns have increasingly adopted targeted approaches using varied net types based on local data. IRS is sparsely deployed, but where it is used, rotation of insecticides with differing modes of action is practiced. Despite existing strengths, such as subnational tailoring of interventions, major challenges persist, including inactive monitoring sites and limited data availability due to financial and logistical constraints. The assessment identified important recommended actions, including increased mobilization of domestic financing of resistance monitoring and management to offset shortfalls in external funding, updating of national IRM plans regularly by realistically aligning with available resources, and improved tailoring of effective vector control through high-quality and localized resistance and malaria risk data.
Conclusion: Insecticide resistance remains a significant threat to malaria control efforts across sub-Saharan Africa. Robust, adaptable IRM plans are essential to address this challenge. Case studies from Cameroon, Côte d'Ivoire, and mainland Tanzania reveal that such policy plans exist but implementation gaps, largely driven by funding shortages (a challenge that has increased since the study was completed), undermine the effectiveness of existing strategies. Strengthening domestic resource mobilization, enhancing multisectoral coordination, and investing in systematic entomological surveillance are critical to ensure evidence-based, sustainable vector control programmes.
(© 2025. The Author(s).)
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Grant Information: PO8615 UK International Development from the UK Government [Health Research Programme Consortia (RPCs): RAFT (Resilience against Future Threats through Vector Control)
Contributed Indexing: Keywords: Cameroon; Côte d’Ivoire; Insecticide resistance; Mainland Tanzania; Malaria; Resistance management
Substance Nomenclature: 0 (Insecticides)
Entry Date(s): Date Created: 20251105 Date Completed: 20251106 Latest Revision: 20251108
Update Code: 20251108
PubMed Central ID: PMC12590846
DOI: 10.1186/s12936-025-05606-0
PMID: 41194077
Database: MEDLINE
Description
Abstract:Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: All the authors approved the final version of the manuscript for publication. Competing interests: The authors declare no competing interests.<br />Background: Malaria remains a significant public health challenge in sub-Saharan Africa (SSA), where vector control strategies, particularly insecticide-treated nets (ITNs) and indoor residual spraying (IRS), have played a critical role in reducing transmission. However, the emergence and spread of insecticide resistance among malaria vectors threatens to undermine these gains. In response, many countries in the region have developed national insecticide resistance management (IRM) plans. This study evaluates the adequacy and implementation of these plans in Cameroon, Côte d'Ivoire, and mainland Tanzania, aiming to identify key challenges and best practices, and to develop actionable recommendations applicable to these and other countries with similar contexts.<br />Methods: A mixed-methods approach was employed, incorporating document reviews, epidemiological and entomological data analysis, and discussions with stakeholders and experts in 2023. The evaluation focused on the alignment of national IRM plans with national malaria control strategies, their operational effectiveness, and the ability to guide effective monitoring and management of insecticide resistance. The assessment was conducted before changes in the global aid funding landscape.<br />Results: Each country has developed a 5-year IRM plan; however, the plans for Côte d'Ivoire and mainland Tanzania were found to be outdated. While the plans align well with national malaria strategies and international guidelines, implementation has been hindered by inadequate domestic funding and heavy reliance on external donors. Sentinel site coverage for resistance monitoring remains limited, though ITN campaigns have increasingly adopted targeted approaches using varied net types based on local data. IRS is sparsely deployed, but where it is used, rotation of insecticides with differing modes of action is practiced. Despite existing strengths, such as subnational tailoring of interventions, major challenges persist, including inactive monitoring sites and limited data availability due to financial and logistical constraints. The assessment identified important recommended actions, including increased mobilization of domestic financing of resistance monitoring and management to offset shortfalls in external funding, updating of national IRM plans regularly by realistically aligning with available resources, and improved tailoring of effective vector control through high-quality and localized resistance and malaria risk data.<br />Conclusion: Insecticide resistance remains a significant threat to malaria control efforts across sub-Saharan Africa. Robust, adaptable IRM plans are essential to address this challenge. Case studies from Cameroon, Côte d'Ivoire, and mainland Tanzania reveal that such policy plans exist but implementation gaps, largely driven by funding shortages (a challenge that has increased since the study was completed), undermine the effectiveness of existing strategies. Strengthening domestic resource mobilization, enhancing multisectoral coordination, and investing in systematic entomological surveillance are critical to ensure evidence-based, sustainable vector control programmes.<br /> (© 2025. The Author(s).)
ISSN:1475-2875
DOI:10.1186/s12936-025-05606-0