Low-cost solution to parasite, poverty at risk from possible NSF cuts

In the villages of rural Senegal, collecting water for cooking is a daily necessity - and a daily gamble.

Residents who wade into or draw from local waterways risk contracting schistosomiasis, a parasitic disease that infects an estimated 250 million people worldwide and puts more than 800 million at risk. The illness causes fever, abdominal pain and chronic debilitation. Over time, it chips away at people's ability to work, earn and provide for their families.

A proven, low-cost intervention, developed by an international team co-led by Cornell, could break the cycle. But the future of the project is uncertain. Most of its funds are provided by the National Science Foundation's Social, Behavioral and Economic Sciences (SBE) directorate, which the Trump administration has proposed eliminating in its 2027 budget plan.

"We were pleased to receive a $1.6 million, 5-year NSF award for this lifesaving work, and we've spent more than $1 million already," said Chris Barrett, the Stephen B. and Janice G. Ashley Professor of Applied Economics and Management in the SC Johnson College of Business, and the project's principal investigator at Cornell. "We remain hopeful the federal government evaluates projects like ours on merit and commits to continued funding for scientific research. If this grant disappears, we would lose crucial data collection on an ongoing experiment."

The large-scale study, "Integrating Socio-Economic and Environmental Interventions to Improve Well-Being in Vulnerable Communities," tests whether public information campaigns will encourage more than 2,000 Senegalese households to adopt the intervention: harvesting the aquatic vegetation that hosts the freshwater snails that vector schistosomiasis, to not only break the parasite's life cycle but also leverage the plants' high economic value as a fertilizer, animal feed and source of income.

The project aims to disrupt an insidious feedback loop, where poverty worsens disease and disease deepens poverty, which researchers call a poverty-disease trap. The team's research sits at the crossroads of public health, ecology and economics - the kind of boundary-crossing science that is often hardest to sustain when research budgets tighten.

The project is rooted in a landmark 2023 study published in Nature in which Barrett, Cornell doctoral candidate Molly Doruska, biologist Jason Rohr of the University of Notre Dame, and a multinational team of collaborators documented a striking low-cost intervention. In northern Senegal's Saint-Louis and Louga regions - some of the most schistosomiasis-burdened communities on Earth, where prevalence among schoolchildren can exceed 87% - the team removed aquatic vegetation from water access points.

The overgrowth, fed by fertilizer and livestock manure runoff, creates ideal habitat for the freshwater snails that host Schistosoma, the parasitic flatworm that causes the disease. When researchers cleared more than 400 metric tons of plants from these sites, snail populations fell and infection rates dropped by nearly one-third.

Crucially, the removed vegetation didn't go to waste. Dried and fed to livestock, it proved a low-cost substitute for purchased feed. Composted and applied to crops, it increased yields as much as chemical fertilizers, at a fraction of the price. Doruska and Barrett calculated that the economic benefits were roughly nine times the cost of the intervention. The public health innovation was also a winning agricultural strategy.

But there was a catch, Barrett said. Those results came from researcher-managed trials. For the approach to matter at scale and be sustained - to actually lift communities out of poverty-disease traps - local residents themselves would need to take it on.

Across 104 villages in the Senegal River Valley, the team is running a pre-registered cluster randomized controlled trial. Villages are randomly assigned to receive different information campaigns: some learn about the public health benefits of removing aquatic vegetation, others learn about the private agricultural benefits (cheaper compost and livestock feed) and some receive both messages. A control group receives neither. The research team completed baseline data collection in May 2024, with households and villages assigned to treatment protocols shortly after.

The study tracks whether and how those messages shift behavior, measuring vegetation removal efforts, snail populations, schistosomiasis infection rates in children, household incomes, agricultural productivity and, following an expansion of the study's scope, children's school participation, cognitive performance and learning.

"Harvesting this invasive plant might boost household income in several ways," said Barrett, who is also a professor in the Cornell Jeb E. Brooks School of Public Policy. "It could be used as low-cost feed to keep livestock alive and lactating during the dry season. And we're experimenting with how to create a direct market for it, to turn it into commercial compost to sell to gardeners in cities."

Researchers are also watching for unintended effects: whether encouraging individuals to harvest aquatic vegetation as a personal resource might inadvertently undermine communal water management or erode the cooperative norms that poor rural communities depend on.

Losing funding at this stage would be particularly damaging, Barrett said. The team has collected baseline data. They've assigned villages treatment protocols. Community members have already received information sessions, delivered in local languages, explaining the benefits of vegetation removal and how to safely conduct it.

Participants were provided with chest waders, shoulder-length gloves and pitchforks, along with instruction in how to protect themselves from infection during the process. The trial is mid-stream. Abandoning it now would leave the communities who agreed to participate, and whose health outcomes the project is meant to improve, without follow-up, without final measurement and without evidence on whether the intervention works at scale.

The disease itself would not pause. Schistosomiasis prevalence rebounds rapidly after drug treatment alone: In this region, infection rates among children routinely return to 70% to 90% within a year of deworming.

The NSF-funded study is specifically designed to address why. Without data on whether community-managed vegetation removal can break that cycle, Barrett said the public health field loses one of its most promising evidence-based strategies for the world's second most socioeconomically burdensome parasitic disease after malaria.

The project's reach extends well beyond Senegal. Schistosomiasis is endemic across Sub-Saharan Africa, Southeast Asia and Latin America. The snail-hosting aquatic plant the Cornell team focuses on, Ceratophyllum demersum, grows throughout those regions. Evidence that community-managed, self-sustaining interventions can reduce infection would have implications for development policy far beyond a single country or river valley.

"This sort of project that requires deep interdisciplinary collaboration with field-based basic science - that's a package that National Science Foundation can uniquely facilitate," Barrett said.

It brings together economists, parasitologists, ecologists, remote sensing experts, and public health researchers from Cornell, the University of Notre Dame, the University of Copenhagen and multiple Senegalese institutions. That kind of collaborative infrastructure, built over years, spanning continents, grounded in deep community relationships, cannot be quickly reassembled once dismantled.

"We're establishing that you can achieve gains in incomes for poor people, improvements in diets and water access, removal of an invasive plant species and a reduction in disease," Barrett said. "There aren't that many places you can get these win-win-wins. It's a unique opportunity."