Now that it’s flu season, most of us are worried about catching the virus from a sneezing coworker. Though we mostly think about disease transmission between people, pathogens like influenza are also transmitted between species (remember swine flu?). This process of pathogen transmission from non-human species to humans is critical for researchers and health care providers to better understand. There are a huge number of factors in the environment that can affect how a pathogen moves between species. Despite this complexity, some interesting patterns have been uncovered by recent research from Joseph Mihaljevic and his coworkers in Dr. Piet Johnson’s lab in CU Boulder’s Ecology and Evolutionary Biology department.