Rice expansion and public health in SSA – cross-sectoral collaboration needed

By Melanie Connor and Pauline Chivenge

Rice production in sub-Saharan Africa (SSA) is steadily increasing, fuelled by a rising demand for food, population growth, urbanisation and changing dietary preferences. Currently, rice self-sufficiency rates are low and do not meet domestic requirements, resulting in Africa importing about 45 per cent of its rice requirements. As a response to the growing demand, many SSA countries developed National Rice Development Strategies (NRDS) under the Coalition for African Rice Development (CARD), aiming to double rice production. Across SSA, rice production has grown, driven largely by area expansion, often converting natural habitats, with most NRDSs targeting to double or triple irrigated rice production, positioning irrigation as a cornerstone for future productivity gains. For countries like Tanzania, that means expanding the irrigated rice production area to half a million hectares.  

Climate and public health trade-offs

While irrigated rice production systems are more profitable and higher yielding than rainfed systems, boosting food security, they also pose climate and public health trade-offs. Conventional irrigated rice production, characterised by transplanting and continuous flooding, is water-intensive and generates substantial emissions of methane, a potent greenhouse gas which contributes to global warming. In response, agronomic win-win solutions such as alternate wetting and drying (AWD), direct seeded rice (DSR) and rice-fish co-cultures maintain or enhance rice productivity while reducing input use, especially water and cutting methane emissions.

A rice field in Tanzania. Photo: Melanie Connor

Another often-overlooked challenge is that in SSA, irrigated rice systems create ideal breeding grounds for mosquitoes, especially Anopheles gambiae, the primary malaria vector, and therefore increase malaria transmission. These aquatic environments can also provide suitable habitats for freshwater snails that transmit schistosomiasis, highlighting how rice systems can simultaneously influence multiple vector-borne diseases. Schistosomiasis is a devastating parasitic disease which is prevalent in rice fields and is transmitted by intermediate host snails. However, the occupational risk of schistosomiasis to people working in irrigated rice fields is not well established yet.

Malaria – one of the deadliest diseases in SSA

Despite decades of global investment, malaria remains one of the deadliest diseases in SSA, accounting for 95 per cent of global cases and 97 per cent of malaria-related deaths world-wide. Annually, malaria claims the lives of approximately 600,000 people, with children under five years accounting for 76 per cent of global malaria deaths. Most malaria control efforts focus on providing insecticide-treated nets, vaccine development, and medical treatment. However, far less investment has been directed towards managing mosquito breeding sites, despite clear evidence that African malaria vector species are exceptionally well-adapted to breeding in rice fields.

Climate change can amplify the threat to public health and malaria fight, with projected warmer climates and increased precipitation, often resulting in enhanced occurrence of flash floods, potentially promoting proliferation of malaria vector abundance. A recent review clearly shows that communities close to irrigated rice are exposed to greater malaria risk. Expansion of irrigated rice production, coupled with warmer temperatures and changing rainfall patterns, increasingly drives malaria and schistosomiasis transmission across many rice-growing regions in SSA.

Mosquito larvae. Photo: Melanie Connor

Cross-sectoral coordination needed

While development goals are clearly defined across different sectors, with, for example, African health ministers planning to eliminate malaria to improve public health, agricultural ministers aiming to improve food security by intensifying irrigated rice production and environmental ministers seeking the reduction of greenhouse gas emissions, the sectors mostly operate in isolation. Coordination across the different sectors to align these development goals remains weak. Whereas all three – food security, climate resilience and public health improvement– are highly desirable goals, the intensification of irrigated rice production often creates trade-offs that risk undermining progress in both health and climate outcomes. Governments in SSA have proposed expanding and intensifying irrigated rice to reduce costly rice imports.

However, realising these benefits requires collective action to eliminate climate and public health trade-offs, ensuring that productivity gains do not come at the expense of sustainability and community well-being. This, therefore, requires deliberately integrating agricultural and public health practices to control malaria and schistosomiasis without negating food security attainment and climate mitigation goals.

A plethora of different rice growing practices exist, especially to mitigate greenhouse gas emissions without profit loss for farmers through climate-smart nutrient and water management practices, in particular DSR, AWD and rice-fish co-cultures. These practices may influence mosquito vector and schistosomiasis-carrying snail abundance. Furthermore, rice-fish co-cultures have been shown to enhance rice productivity while reducing methane emissions (6) and potentially help control mosquito populations by consuming larvae.

Generally, mosquito and snail control is predominantly done through pesticide application and requires repeated application, posing further health risks. It is also costly, which questions its sustainability for farmers and the environment. This highlights an important research gap to explore alternative options to reduce vector abundance in rice fields that are sustainable, cost-effective, easy to apply and do not pose additional risks to farmers’ health or livelihoods. A full understanding of the relationship among options of rice management in African rice fields that simultaneously improve food security, reduce greenhouse gas emissions and improve public-health outcomes is yet to be addressed through cross-sectoral, multidisciplinary teams.

Collective action is required involving agronomists working in rice production systems, entomologists and ecologists with expertise in malaria-causing mosquitoes and schistosomiasis-carrying snails, epidemiologists and social scientists who will need to provide insights on options that generate co-benefits across climate, public health and food production.

This challenge highlights the value of adopting a One Health perspective recognising that human health outcomes are shaped by factors across human, animal and environmental domains. The approach needs to address vector breeding (mosquitoes and snails) at its environmental and systemic roots, complementing existing preventive tools. Embedding vector-borne disease reduction into the research and development agenda for rice production systems in SSA offers a practical pathway to deliver co-benefits for public health, climate resilience, and food security.

Melanie Connor is a senior social scientist at the International Rice Research Institute (IRRI) in  Nairobi, Kenya, specialised in behavioural and risk research. She holds a doctoral degree from ETH Zurich, Switzerland, and has 20 years of experience in research.
Contact: M.Connor(at)cgiar.org

Pauline Chivenge is a senior scientist in Cropping Systems Agronomy/Climate Change and Country Representative at the International Rice Research Institute (IRRI) in Dar es Salaam, Tanzania. Her work focuses on advancing sustainable and climate-smart innovations in rice farming systems. She earned her doctoral degree from the University of California, Davis and brings over 25 years of research experience in smallholder farming systems. 

References:

• van Oort, P. A. J., Saito, K., Tanaka, A., Amovin-Assagba, E., Van Bussel, L. G. J., van Wart, J., de Groot, H., van Ittersum, M. K., Cassman, K. G. & Wopereis, M. C. S. (2015). Assessment of rice self-sufficiency in 2025 in eight African countries. Global Food Security 5: 39–49.
• Seiler, W., Holzapfel-Pschorn, A., Conrad, R., Scharffe, D., 1983. Methane emission from rice paddies. Journal of Atmospheric Chemistry 1, 241-268.
• Sander, B.O., Wassmann, R., Siopongco, J.D., 2016. Mitigating greenhouse gas emissions from rice production through water-saving techniques: potential, adoption and empirical evidence. Climate change and agricultural water management in developing countries. CABI Wallingford UK, pp. 193-207.
• Jiang, Y., Carrijo, D., Huang, S., Chen, J.I., Balaine, N., Zhang, W., van Groenigen, K.J., Linquist, B., 2019. Water management to mitigate the global warming potential of rice systems: A global meta-analysis. Field Crops Research 234, 47-54.
• Pathak, H., Sankhyan, S., Dubey, D.S., Bhatia, A., Jain, N., 2013. Dry direct-seeding of rice for mitigating greenhouse gas emission: field experimentation and simulation. Paddy and Water Environment 11, 593-601.
• Hussain, S., Peng, S., Fahad, S., Khaliq, A., Huang, J., Cui, K., Nie, L., 2015. Rice management interventions to mitigate greenhouse gas emissions: a review. Environmental Science and Pollution Research 22, 3342-3360.
• Zhang, W., Xu, M., Lu, J., Ren, T., Cong, R., Lu, Z., Li, X., 2023. Integrated rice-aquatic animals culture systems promote the sustainable development of agriculture by improving soil fertility and reducing greenhouse gas emissions. Field Crops Research 299, 108970.
• Sack, A., Selland, E., Bakhoum, S., Seck, M., Jouanard, N., Magblenou, L. D. & Rohr, J. R. (2025). Human Schistosoma exposure risk in rice fields and an exploration of fish species for snail and schistosomiasis biocontrol. PLOS Global Public Health 5(6): e0004726.
• World Health Organization, 2024. World malaria report 2024: addressing inequity in the global malaria response. Geneva: Licence: CC BY-NC-SA 3.0 IGO.
• (Chandler, J. A., Highton, R. B., & Hill, M. N. (1975). Mosquitoes of the Kano Plain, Kenya. I. Results of indoor collections in irrigated and non-irrigated areas using human bait and light traps. Journal of medical entomology, 12(5), 504–510. https://doi.org/10.1093/jmedent/12.5.504
• Megersa DM, Luo X-S. Effects of Climate Change on Malaria Risk to Human Health: A Review. Atmosphere. 2025; 16(1):71. https://doi.org/10.3390/atmos16010071).
• Chan, K., Tusting, L. S., Bottomley, C., Saito, K., Djouaka, R. & Lines, J. (2022). Malaria transmission and prevalence in rice-growing versus non-rice-growing villages in Africa: a systematic review and meta-analysis. The Lancet Planetary Health 6(3): e257–e269.

Further reading:

Rural 21 issue 4/2020: One health