Featured Student: Caitlin Mertzlufft

Caitlin Mertzlufft is a second year PhD student in Integrative Conservation and Geography. With a background in both geography and public health, her research focuses on the spread and distribution of diseases that are transmissible between humans and other species of animals, called zoonoses. Zoonoses comprise nearly sixty percent of all diseases currently known to affect humans, including many that have featured prominently on media outlets in the last decade: H1N1 “swine” flu, the severe acute respiratory syndrome (SARS), and most recently, Ebola and measles.

Zoonoses lie at the juncture of human, animal, and environmental interaction, and are emerging in greater frequencies in recent decades due to large scale human-environmental interaction. Unprecedented increases in human-induced environmental degradation, through practices such as deforestation or mountain-top removal, result in alarming loss of native habitats for wildlife. This forces wildlife into spaces occupied by humans and domesticated animals, including both pets and livestock, which facilitates the spread of pathogens across populations and between species. In the last decade, interdisciplinary collaboration surged in response to a combination of increased funding for zoonotic research and concurrent scientific evidence that zoonoses are emerging with increased frequency. Although an attempt to acknowledge a more interconnected worldview, these collaborations overwhelmingly prioritize human health or highlight only a single aspect of the disease transmission cycle. By failing to holistically consider the influence and ability of both human and non-human populations to affect disease transmission, the dynamics of zoonotic disease are oversimplified. This limits effective mitigation approaches. Caitlin argues that zoonotic diseases emerges from a cyclical, iterative interaction between human and non-human species, each responding to actions of the other. In order to address these connections in a truly holistic manner, she plans to approach zoonotic disease through an understanding of the network of human and non-human actors involved. This is particularly fascinating from a geographic perspective, because while zoonotic disease is by definition spread through multispecies interaction, the specific drivers of these interactions vary dramatically across regions and countries. Caitlin’s research examines the associations that bring interspecies networks into being, and assesses regionally-specific social, cultural, political, economic, and ecological drivers that dictate the actions and interaction of human and non-human populations.

Specifically, Caitlin’s dissertation research identifies the network of actors associated with Chagas disease transmission in Panama. Chagas disease is a leading cause of human illness and death due to heart disease in Central and South America. This disease is spread by multiple species of triatomine bugs, and affects a number of domesticated animals and wildlife in addition to human populations. In Panama, the triatomine species that transmits Chagas disease lives primarily in palm trees, which are associated with secondary growth following human landscape disturbance. This landscape disturbance is strongly correlated with agriculture. Caitlin plans to assess specific transmission networks of Chagas disease across forested, semi-forested, and peri-domestic landscape gradients in Panama to understand how human-induced landscape change in association with agriculture alters interaction patterns of the human and non-human actors, and therefore, Chagas transmission itself. A better understanding of Chagas transmission will inform more effective treatment and prevention strategies.

Caitlin’s advisor is Dr. Marguerite Madden in the Department of Geography. Caitlin’s research on Chagas disease is in collaboration with an interdisciplinary and international group of scholars, many affiliated with the Center for Integrative Conservation Research, who have been working on long term studies of Chagas ecology and its response to environmental change. Key UGA collaborators include Drs. Susan Tanner and Julie Velasquez Runk from the Department of Anthropology, Dr. Nicole Gottdenker from the Department of Pathology, Dr. Sara Robb from the Department of Biostatistics and Epidemiology, as well as several fellow doctoral students. International collaborators include Drs. Jose Calzada and Azael Saldaña of the Gorgas Memorial Institute. This work is further facilitated by the Smithsonian Tropical Research Institute.