Listeria is everywhere.
And because it can be found in so many places, it provides the ideal model for studying the evolution and ecology of bacterial pathogens. L. monocytogenes causes death in as many as 20 percent of people who contract listeriosis. It also poses serious health risks to agricultural animals. While scientists understand the microbiology of the bacterium, how it is transmitted through food, animals, water and soil is not well understood. All the while we will be trying to understand the basic biology that forms the base for those associations.