We examine interactions among anthropogenic environmental change; biodiversity; and the ecology and emergence of pathogens in wildlife, domestic animals, and people using diverse pathogen study systems (eukaryotic parasites, bacteria, and viruses) in Sub-Saharan Africa, Madagascar, and Latin America. This work contributes simultaneously to our understanding of two key issues:
Ecology and Epidemiology of Emerging Wildlife-Borne Diseases in the Tropics
Globally, three-quarters of all emerging diseases are zoonotic in origin and represent an increasing burden on the health and well being of humans, domestic animals, and wildlife. The overall goal of our work within this context is to determine how and why anthropogenic changes to tropical forests place people and wildlife in such ecosystems at increased risk of pathogen exchange. The central hypothesis of this work is that key human behaviors, wildlife behaviors, ecological conditions, and landscape features increase the risks of interspecific disease transmission. This effort entails a combination of epidemiology, molecular ecology, behavioral ecology, social and clinical survey, and spatially explicit modeling. The ultimate products are implementable plans for protecting human and wildlife health, while simultaneously ensuring the sustainability of the ecosystems within which they live. In addition to better understanding the role of human induced habitat changes on pathogen dynamics, this work provides the opportunity for early detection of novel pathogens that may pose a threat to global health and / or wildlife conservation.
Pathogen Introduction as a Threat to Endangered Primates
The close phylogenetic relationship between humans and other primates creates exceptionally high potential for pathogen exchange. This has resulted in disease emergence in humans as an unintentional affect of the hunting and butchering of the African great apes, responsible for human outbreaks of Ebola and the global AIDS pandemic, as well as high rates of mortality in wild chimpanzee populations (Pan troglodytes) associated with anthropozoonotic transmission of human respiratory viruses. We have demonstrated that proximity between wild primates and people can promote transmission of the common gastrointestinal bacterium Escherichia coli, as well as pathogenic enterics such as Cryptosporidium and Shigella. Our work stresses that direct contact between species is not necessary for interspecific disease transmission. Indeed, most transmission of gastrointestinal pathogens between people, livestock, and wild primates is probably indirect and environmental. Many of the pathogens we are examining such as Cryptosporidium, Giardia, and enteric bacteria (i.e., Shigella, Salmonella, E. coli, etc.) readily contaminate water and soil and may persist in wet areas, while others we examine such as rickettsial agents and arboviruses are readily transmitted by vectors such as ticks and mosquitoes. Demonstration of human pathogens negatively impacting wild primates has sparked considerable debate concerning the costs and benefits to endangered primate populations of scientific research, ecotourism, and current conservation and management paradigms. Despite the disease-related risks, the consensus is that both research and tourism have contributed in overwhelmingly positive ways to primate conservation, enhancing their long-term survival by increasing their scientific and economic value. Nevertheless, such activities as well as overlap of humans and non-human primates may have unintended consequences on the health and survival of wild primate populations. We are working to better understand such threats and to propose mitigation strategies.