A solution that doesn't require choosing between competing goods
In the rice paddies of rural Senegal, where the act of farming has long carried the hidden cost of disease, researchers have found that an ancient agricultural practice may quietly disrupt one of the world's most persistent cycles of poverty and illness. By introducing native fish into flooded fields, a team from the University of Notre Dame has demonstrated that snail populations — the carriers of schistosomiasis — can be suppressed not through chemical intervention or medical campaigns alone, but through the restored logic of a functioning ecosystem. The study, touching more than 400 households along the Senegal River basin, suggests that when nature's relationships are honored rather than overridden, the benefits tend to multiply in ways no single-purpose solution can match.
- Schistosomiasis traps over 220 million people in a cycle that treatment alone cannot break — the drug cures, but the flooded fields reinfect, and the disease returns with the next harvest.
- Rice farmers and their children bear the sharpest burden, their daily labor in standing water making the paddies both livelihood and source of infection.
- Researchers introduced African Bonytongue and Nile tilapia into Senegalese rice fields, betting that fish who naturally prey on or outcompete snails could quietly dismantle the disease's transmission chain.
- The fish required no supplemental feeding, snail populations declined, and rice yields climbed more than 25 percent — a rare convergence of health, agricultural, and economic benefit from a single intervention.
- The team is now working to determine whether the approach can scale across endemic regions, with additional trials underway and the prospect of a replicable model for addressing disease, hunger, and poverty together.
Schistosomiasis remains one of the most entrenched neglected tropical diseases in the world, infecting more than 220 million people and resisting decades of drug-based campaigns. The disease is especially punishing in sub-Saharan Africa, where it is woven into the fabric of agricultural life. Rice farmers and their families face the highest exposure — the parasitic worms responsible for infection are spread by freshwater snails that inhabit the standing water of rice paddies, turning the fields that sustain communities into a source of chronic illness. A drug exists to treat schistosomiasis, but it cannot prevent reinfection, leaving farmers caught in a cycle of recovery and relapse that steadily erodes income and opportunity.
Researchers at the University of Notre Dame, working with partners across multiple institutions, set out to test whether an old agricultural technique could interrupt that cycle. In rural Senegal, along the northern Senegal River basin, they introduced two native fish species — African Bonytongue and Nile tilapia — into rice fields. Both species naturally suppress snail populations, either by eating them or by competing for the same food sources. The team studied more than 400 households in the region and confirmed what prior data suggested: children of rice farmers contracted schistosomiasis at significantly higher rates than children of non-farming families.
The results of the fish introduction were striking on multiple fronts. Snail populations fell in fields stocked with both species. The fish sustained themselves without supplemental feeding, pointing toward a self-sufficient system. Rice yields rose by more than 25 percent. Soil quality improved. And farmers gained a new income stream by harvesting and selling the fish. In a single intervention, the approach addressed disease transmission, food production, and economic resilience simultaneously.
Lead author Emily Selland described the work as an effort to repurpose a familiar agricultural technique for infectious disease control. The research team believes the early results justify scaling the approach across rice-growing regions where schistosomiasis is endemic. Funded by the National Science Foundation, Notre Dame's Poverty Initiative, and Stanford's Sustainability Accelerator, the project is already moving into expanded trials — carrying with it the possibility of a model that achieves what sustainable development rarely manages: solving several hard problems at once.
Schistosomiasis has infected more than 220 million people worldwide, and despite decades of drug treatment campaigns, it remains one of the most stubborn neglected tropical diseases on the planet. The disease is particularly brutal in sub-Saharan Africa, where it feeds on poverty and geography in equal measure. Rice farmers and their families face the highest risk—the parasitic worms that cause the infection are spread by freshwater snails that live in the standing water of rice paddies, making the very act of farming a vector for disease.
Researchers at the University of Notre Dame, working across multiple institutions, decided to test whether an old agricultural technique might solve a modern health crisis. They introduced two native fish species—African Bonytongue and Nile tilapia—into rice fields in rural Senegal, along the northern Senegal River basin, a region where schistosomiasis is endemic. The logic was straightforward: these fish naturally eat snails or compete with them for food, and if snail populations dropped, so would disease transmission. What made the approach unusual was that it promised something rare in global health work: a solution that didn't require choosing between competing goods.
The team studied more than 400 households in the region and found what they expected: children of rice farmers contracted schistosomiasis at higher rates than children of non-farmers. The disease creates a trap. A drug exists to treat it, but the drug cannot prevent reinfection. Farmers and their families get sick, recover, return to the fields, and get sick again—a cycle that drains income, energy, and opportunity from entire communities.
What happened when the fish were introduced was striking. In fields stocked with both species, snail populations fell noticeably. The fish thrived without supplemental feeding, suggesting the system could sustain itself. But the benefits extended far beyond disease control. Rice yields increased by more than 25 percent. Soil nutrients improved. And farmers gained a secondary income stream from harvesting and selling the fish themselves. The intervention, in other words, addressed three problems at once: it reduced disease transmission, boosted food production, and created economic opportunity.
Emily Selland, the lead author and a graduate student in the research group, described the work as an attempt to take an agricultural technique used elsewhere and repurpose it for infectious disease. The team believes the initial results are strong enough to warrant the next phase: determining how the approach might scale across rice-growing regions where schistosomiasis is common. If the findings hold as the work expands, rice-fish coculturing could become a model for how to address health, food security, and poverty simultaneously—the kind of integrated solution that sustainable development requires but rarely achieves. The research was funded by the National Science Foundation, Notre Dame's Poverty Initiative, and Stanford's Sustainability Accelerator, and additional trials are already underway.
Citas Notables
We don't always have to choose between improving human health, increasing food production and protecting the environment.— Jason Rohr, University of Notre Dame, corresponding author
We're taking an agricultural technique used in other regions and expanding it to infectious disease transmission, tackling schistosomiasis while supporting community development.— Emily Selland, lead author and graduate student, Notre Dame
La Conversación del Hearth Otra perspectiva de la historia
Why does schistosomiasis hit rice farmers so much harder than other people?
Because they're in the water constantly. The snails that carry the parasite live in the standing water of rice paddies. You can't farm rice without being in that water, so the exposure is almost unavoidable.
And the drug doesn't solve it?
The drug treats the infection, but it doesn't prevent you from getting reinfected. So a farmer gets treated, goes back to work in the fields, and catches it again. It's a cycle that never breaks.
So the fish are doing what—eating the snails?
Both eating them and competing with them for resources. The two species work together. And the remarkable part is they don't need to be fed. They sustain themselves in the rice field ecosystem.
What about the rice yield increase? Is that because the fish are fertilizing the water?
Partly that, yes—the fish contribute nutrients. But they also likely reduce pests and improve soil structure. It's a more complex system than monoculture, so multiple benefits emerge.
Can this actually scale? Or is it a nice pilot that won't work everywhere?
That's the honest question now. The initial results from Senegal are encouraging, but scaling means training farmers, ensuring fish availability, managing the system across different environments. It's doable, but it requires infrastructure and support that doesn't exist yet in many places.