The WEFE nexus and One Health: Complex links present challenges and opportunities

In the latest webinar in the CGIAR Initiative on NEXUS Gains' long-running series, experts investigated the complex connections between the WEFE nexus and One Health.

"One Health advocates that human, environmental, and animal health are closely interlinked and that interventions should actively consider these interlinkages to achieve larger impacts," explained Dr. Vartika Singh, a Senior Research Analyst at the International Food Policy Research Institute, as she introduced the webinar. "One Health is intricately linked to the WEFE nexus, whether through the availability and quality of water, means of energy production, or the production of food."

Dams and malaria

These links were explored first by Dr. Jonathan Lautze, a Research Group Leader at the International Water Management Institute (IWMI) and NEXUS Gains Coordinator for Southern Africa, who focused on dams and human health. "Dams can have a lot of very good benefits for human health, such as reducing the effects of floods and droughts, supporting food production, and enhancing energy production," he noted. "However, the edges of reservoirs can be breeding grounds for mosquitoes, which in some places leads to increased malaria transmission in nearby communities."

A 2015 study mapped over 1,000 dams in Africa and conservatively estimated that 1.1 million malaria cases every year are associated with large dams. Dr. Lautze added that this figure may treble by the 2080s due to rising temperatures and shifting rainfall patterns triggered by climate change. Despite this finding, Dr. Lautze stressed that the relationship was a complex one, pointing out that dams in areas with high or very low malaria prevalence were unlikely to increase disease incidence. Site-specific factors, such as reservoir management, local housing conditions, and topography - with steeper-sided reservoirs harboring fewer mosquito larvae - also affect malaria incidence.

"For me, the important lesson here is that this variability presents opportunities for management," Dr. Lautze concluded. "Feasibility studies and proper planning for dams - taking into account factors such as existing malaria prevalence, reservoir gradient, and climate change predictions - can help minimize the risk of increasing malaria rates."

Integrated fish-rice systems

The focus shifted to Asia with the second presentation. Dr. Matthew McCartney, a Research Group Leader at IWMI and NEXUS Gains Lead, explained how the integration of rice, fish, irrigation, and water storage in inland fisheries could improve the sustainability of these vital but overlooked systems.

"Inland fisheries provide jobs for 17 million fishers and generate USD 19 billion annually, making them important for the livelihood security of many millions of people," he said. "They also strengthen nutrition security by providing a vital source of protein, minerals, and micro-nutrients. Traditional rice-fish systems in Asia - which have very low agrochemical inputs - are an important source of biodiversity, home to hundreds of species of fish, insects, crustaceans, mollusks, reptiles, amphibians, and plants." In places like Laos, many of these species supplement, add diversity and enhance the nutritional value of diets.

However, the expansion and intensification of irrigated agriculture is adversely impacting inland fisheries. Dammed rivers prevent fish from migrating to breed or feed, and increasing agrochemical use is harming biodiversity and lowering fish production.

One solution is to better integrate fisheries into the design and management of rice and irrigation systems. "The aims of integrated rice-fish systems are to increase climate resilience and food and nutritional security of local communities', boost water productivity, and generate more income per hectare," explained Dr. McCartney. Integrating fisheries requires much lower agrochemical use, which protects not only fish but also other biodiversity. Other promising options include ecosystem-based management to enhance reservoir fisheries, mimicking natural habitats and processes to support healthy fish populations.

Data and greater awareness still needed

During the panel discussion that followed, Alvin Lopez, Senior Natural Resources and Agriculture Specialist at the Asian Development Bank, agreed that rice-fish systems were hugely important. "But without solid data from expert organizations to inform their planning and development," he cautioned, "it's difficult for us to move forward on these issues. Technical advice is critically important."

Dr. Timmo Gaasbeek, a Senior Policy Officer Food Security at the Netherlands Ministry of Foreign Affairs, added that increased agrochemical use was also impacting human health, as people are eating fish and other aquatic foods with high concentrations of pesticides. Despite concerning trends such as these, Dr. Gaasbeek reminded webinar attendees that the important links between One Health and the WEFE nexus raised in the webinar continue be overlooked. "We need to bring other people into these discussions," he said. "We need to make them realize that this is really important."

Didn't catch the webinar? You can also listen to the podcast:

View the presentation slides by Jonathan Lautze View the presentation slides by Matthew McCartney

Learn more about all the webinars in the series on the NEXUS Gains Talks landing page and subscribe to the NEXUS Gains newsletter to be the first to hear about upcoming Talks.

This work was carried out under the CGIAR Initiative on NEXUS Gains, which is grateful for the support of CGIAR Trust Fund contributors:www.cgiar.org/funders

Header image: Farmers in Cambodia use fish ponds for crop irrigation. Photo by Fani Llauradó/Worldfish.

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