My research involves epidemiology and medical ecology of infectious diseases potentially transferred between livestock, wildlife and humans and assessing microbial contamination of the environment by livestock and wildlife. A special emphasis is on microbial contamination of surface and groundwater from watersheds located in the Sierra Nevada Range, foothills along the San Joaquin Valley, and coastal regions of central and northern California. Key methods involve linking process-based experimental work with longitudinal epidemiological studies and molecular characterization to characterize rates of environmental loading, fate and hydrological transport, and dissemination of infectious diseases within and between host populations.