Research Summary
My research addresses fundamental questions in disease ecology, particularly focused on vector-borne diseases including tick-, fly- and mosquito-transmitted pathogens across the America's. The central theme of my research is understanding the environmental drivers of vector ecology and pathogen transmission, from microclimate and habitat conditions, to land use change and changes in global climate. Below you can read more about my research program and the core research areas on which work in the lab is focused.
Human cases of tick-borne diseases, most notably Lyme disease, have been increasing in incidence and geographic distribution across the northern hemisphere. This increase is likely being driven by a number of interacting factors including climate and land use change, changes in host community composition and human behavior, along with a concomitant increase in both our ability to detect tick-borne pathogens and in reporting efforts. In North America, there are an estimated 300,000 cases of human Lyme disease each year with geographically distinct disease foci, or regions where the disease is considered to be endemic, including in the northeastern, upper midwestern and far western United States. While the northeastern and upper midwestern foci have experienced geographic expansion and increases in incidence, the far western United States has experienced low and consistent annual incidence in the human population. Understanding this distinct and unique epidemiological pattern is the primary goal of my work on tick-borne disease, informing the questions I have addressed in the field in California.
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Habitat loss and fragmentation have pervasive impacts on natural systems, and are central elements of anthropogenic environmental change. In the US Northeast, a period of reforestation followed agricultural production in the region as people and jobs moved to cities in the early 20th century. Recent expansion back into forests, driven by suburban development has served to fragment forests across the northeastern US. This fragmentation has had important consequences for the animal host communities that support tick populations and transmission of the Lyme disease spirochete in the region, including evidence that fragmented forests support fewer vertebrate species, higher abundance of reservoir hosts for the bacteria and larger populations of ticks. However, these findings and patterns are controversial and the results of studies attempting to link forest fragmentation directly to human disease incidence have been mixed. We tackle the question of the effects of forest fragmentation on human Lyme disease using novel data and statistical techniques.
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Land use, land cover and climate are rapidly changing across the tropics and developing world. Changes including forest fragmentation and loss, urbanization and increasing temperature are having profound effects on the transmission of vector-borne diseases from malaria to dengue, and yellow fever to leishmaniasis. These processes of global change and resulting impacts on vector-borne disease transmission are particularly pronounced in Latin America, where the world's largest remaining tropical forest is steadily being cleared for pasture and agriculture, and recent epidemics of Zika virus and a resurgence of malaria, for example, figure prominently in the public health landscape. Within this complex landscape, we have developed a core research agenda tackling numerous questions at the interface of global change and vector-borne disease transmission.
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In addition to my core research on the ecology of vector-borne disease transmission, I also have collaborations investigating 1) win - win solutions for conservation and human health, 2) the effects of health care intervention on deforestation and forest conservation in Indonesian Borneo, 3) the effects of agricultural production practices on natural systems and biodiversity in California, and 4) Coupled natural-human system dynamics.