Water-restricted environments that experience strong seasonal variation are extremely vulnerable to landscape alteration and pollution from human activities. Increasingly, degradation of limited water resources is identified as an important and urgent problem facing much of the world, in particular Africa. This research project will evaluate coupled human and ecological drivers influencing water quality, and the health of human and animal populations in the Chobe River Region of Botswana. The investigators will use Escherichia coli as a model microorganism to track transmission linkages between the Chobe River and different trophic guilds of wildlife, domestic animals, and humans in the system. Using predictive models calibrated with field samples the researchers will investigate long-term effects of climatic changes; seasonal variation in hydrology; increases in human population; and landscape modification impacts on water quality and human and animal health. This project will identify markers of high-risk environments where coupled human-natural systems influence water quality, forming the foundation of an early-warning system that can be used by communities and governments to improve preparedness and interventions. This project integrates educational and government outreach into a research approach, which aims to develop a more predictive and fundamental understanding of the present and future impact of coupled dynamics of societal change and development on water quality and health and the potential long-term influence of climate change on these interactions.

This research project establishes multidisciplinary scientific networks and international partnerships. The project will support a graduate student-training program between the USA and Botswana, which is integrated with a multifaceted outreach program directed at Botswana youth living in the study area. This approach will strengthen cross-cultural understanding and minority-leadership capacity in scientific discovery. This study promises direct benefits to society through the translation of research findings into developmental policy that will promote the sustainability ecosystems on which human populations depend. Results from this project will advance our understanding of coupled human-natural systems and the influence this has on water quality and health for humans, livestock, and wildlife.

Project Report

Intellectual Merit With nearly 50% of the Earth’s surface characterized as ‘dryland’, the linked issues of water quality, health and water scarcity are identified as urgent global problems. Countries with extensive dry regions are particularly at risk, confronted with the growing crises of increasing population growth and declining water resources. Humans are inextricably coupled to fresh water resources in diverse ways, the availability and quality of which will feed back to influence human development and health. We know little about these interactions, however, and thus, have limited ability to manage couplings between humans and the natural environment that occur in these regions. Through our exploratory study in the dryland region of Chobe, Botswana, we confirmed that significant couplings exist between humans and the natural environment that link back to effect human and animal health and ecosystem function. Although diarrheal disease can be caused by a variety of pathogens, seasonal peaks in disease among communities living in the region were associated with rainfall and flooding and decreases in microbial water quality of the only surface water available in the region - the Chobe River. In order to understand how access to surface water influences human health and diarrhea outbreaks, we compared diarrheal disease patterns in Chobe to that observed at the national level where surface water is only found in three locations, affecting a small proportion of the population. We constructed a unique data set from archived medical reports spanning 30 years and identified significant climate-diarrhea relationships. Dry season diarrheal outbreak peaks differed in timing at the National level, supporting our hypothesis that human – natural environment interactions and surface water are important in diarrheal disease dynamics and human health in our dryland study area. Antibiotic resistance detected in fecal Escherichia coli (a common mammalian gut microorganism) is considered an important signature identifying that the microorganism likely originated in humans. We documented the widespread occurrence of antimicrobial resistance (using a panel of 10 antibiotics) among E. coli isolated from wildlife such as the banded mongoose across protected and unprotected areas in the study region. Resistance levels were similar to that found in E. coli isolated from humans in the area, revealing potiential connections between wildlife and human fecal contamination of the landscape. Evidence of high levels of antimicrobial resistance even within protected areas identifies an important and emerging public health threat. E. coli isolated from mongoose and human sources in the National Park and urban areas were genetically indistinguishable, indicating that exchange of fecal microorganisms between humans and mongoose is occurring. Our results together (some not shown here) suggest that fluvial geomorphology influenced by wildlife and human presence and land use will be important in understanding water quality and provide important insight into the dynamics of microbial movement and storage in the system. Pathogen transmission between humans and wildlife in this coupled system may also influence the coupled dynamics of health. Our work identifies the occurrence of important zoonotic pathogens such as brucellosis and leptospirosis in the region, threating humans who live closely with wildlife, share scarce water resources, and may be exposed to these pathogens through the use of bush meat and other activities. To better understand the influence of human behavior on seasonal outbreaks, we surveyed patients at local health facilities with diarrheal disease, evaluating patient characteristics over wet and dry season outbreaks. With the exception of age of the patient, no significant differences could be identified between variables when compared by outbreak period, supporting the hypothesis of common environmental drivers influencing biannual outbreaks in this region. Our results from this 2-year study have revealed significant connections between human health and the environment and establish an important framework for conducting more advanced research on coupled natural-human systems in dryland regions. Broader impacts Our work under two years of NSF funding has resulted in the publication of five peer-reviewed manuscripts and international training for 2 postdoctoral associates, 3 graduate, and 5 undergraduate students. We successfully developed and delivered the proposed educational program to two primary schools (K-7) in the study region with the curriculum titled "The Chobe River - Our Water, Our Life" and advanced our youth research-mentoring program with three intakes of youth (16 each internship period). We have presented the results of this research and recommendations at two seminars, one national and three international conferences, and to multiple Botswana Government ministries responsible for health and the environment and to their associated departments. We have harnessed the power of social media to highlight project activities using both Facebook (www.Facebook.com/caracalbotswana) and BlogSpot (www.blogspot.healthbotswana.com), the latter having over 9000 hits. Our findings from this work, associated data, and models bring direct benefits to society through improved understanding and management of water quality and health in vulnerable dryland systems found across the globe including regions of the United States.

National Science Foundation (NSF)
Division of Environmental Biology (DEB)
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Alan James Tessier
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