A flooding river moves more than just water. Inundation and draining result in an exchange of matter and organisms — including those that cause disease.

Kathleen Alexander, associate professor of wildlife in Virginia Tech’s College of Natural Resources and Environment, received a $1.8 million grant from the National Science Foundation’s Dynamics of Coupled Natural and Human Systems Program to investigate the underlying processes that link the environment, wildlife, domestic animals, and humans in dryland river systems in southern Africa, driving the accumulation and movement of waterborne disease across the landscape.

Alexander, an affiliate of the Fralin Life Science Institute, will lead a group of university, federal, and nonprofit researchers in the study of a critical dryland river, the Chobe-Linyanti-Kwando system straddling Botswana and Namibia.

Waterborne disease accounts for 90 percent of all infectious disease in developing countries. “It is not just a matter of water contamination,” Alexander said. “Flooding and rainfall can move sediment and fecal microbes across the landscape in complex ways, dramatically influencing water quality even in locations distant to direct contamination of the water.”

In previous National Science Foundation-funded research at her long-term study site in Chobe, Botswana, Alexander has documented the coupled nature of diarrheal disease, water-quality declines, and environmental drivers. The new project will advance this work, evaluating the complex interactions between hydrological, geomorphological, sedimentary, and ecological processes particular to dryland river floodplains and their influence on fecal microbial dynamics, water quality, and human waterborne disease risk.

The team will also evaluate coupled sociocultural and economic processes that influence landscape change and waterborne disease risk, elements that can lead to further environmental degradation and pathogen pollution. “These dynamics are not well understood in dryland river floodplains, impeding management of water quality and health in these vulnerable systems,” Alexander said.

“The aim is to create modeling tools that will make it possible to monitor, manage, and forecast the complex processes that drive water quality declines and human waterborne disease epidemics in dryland river floodplain ecosystems,” Alexander said. “Long-range forecasts that indicate heightened risk of diarrheal disease and degraded water quality will provide lead times to allow public health preparations and application of health interventions.”

Research and outreach activities will be conducted in collaboration with a local nongovernment organization, the Center for African Resource: Animals, Communities and Land Use (CARACAL), which was co-founded by Alexander and Mark Vandewalle and works in close collaboration with local and central government in Botswana.

Educational activities will be directed toward two age groups in the U.S. and Botswana. Elementary school students in Blacksburg and Botswana will meet in a virtual classroom to investigate and learn together the challenges facing river systems near their homes — the New River in Virginia and the Chobe River in Africa. In a second program, Virginia Tech undergraduates will work with Botswana youth, 18 to 24 years old, co-mentoring, learning, and exploring water quality and emergent public and animal health in challenges in river systems from the Americas to Africa.

Research results will support improved land-use planning, water management, and public health policies and approaches particular to dryland river floodplains with applications across the globe. Forecasting tools will be made available for use in predicting environmental waterborne or water-associated disease interactions, epidemic preparedness, and local mitigation needs. The close partnership of Alexander with the Botswana government will ensure that research outcomes will also bring important advances to management of dryland rivers in this region of Africa.

Several members of the research team are from Virginia Tech:

Other research team members include the following:

  • John Bock, professor of anthropology at California State University, Fullerton, who specializes in the social, cultural, and ecological determinants of health and has a long history of research on health and ecology in Botswana
  • Douglas Goodin, professor of geography at Kansas State University, who specializes in remote sensing and geospatial modeling of infectious disease
  • Louis Iverson, landscape ecologist with the U.S. Forest Service, who has a long history of modeling species-climate-landscape interactions
  • Jeffrey Shaman, associate professor with Columbia University’s Mailman School of Public Health, who models and forecasts infectious diseases and their environmental determinants
  • Stephen Tooth, professor of physical geography at Aberystwyth University in Wales

Alexander has worked in Africa for over 20 years, focusing on pathogen dynamics at the human-animal-environmental interface. She is one of few scientists to receive grants from both the National Science Foundation’s Dynamics of Coupled Natural and Human Systems Program and its Ecology and Evolution of Infectious Diseases Program. Learn more at the blogs for each project: Water Quality and Health in Botswana and Disease Ecology of the Social Banded Mongoose.



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