My research has focused on the evolution and ecology of infectious disease in natural population. My fundamental concern is human infectious disease but, somewhat unusually, I have used plants as tractable, accessible models with which to investigate the transmission and dynamics of pathogens in nature. However, we have researched diseases in organisms as diverse as bumble bees, mice, and primates, and include human data sets in our analyses. I also have an interest in the history of evolutionary biology and germ theory, and self-sustaining ecological systems. I retired from teaching eight years ago, and am not taking on graduate students or new post-docs. I now focus on research and writing, with a current interest in clade age and pathogen occurrence in ferns. I have been fortunate to have funding from NIH, NSF, and the Humboldt Foundation, and now collaborate in research with the labs of Mandy Gibson, here at University of Virginia, and Emme Bruns (University of Maryland), Michael Hood (Amherst College), Mike Boots (University of California, Berkeley) and Matthias Rillig (Free University, Berlin).