The environment is a key determinant of infectious disease burden in a population. This course presents an overview of how existing and, in particular, changing global environmental factors can affect the transmission cycle of infectious pathogens in both developing and industrialized countries. It examines issues of water, sanitation and hygiene in resource-limited settings that contribute enormously to childhood death due to infectious diarrheal diseases, and to morbidity and mortality due to neglected tropical diseases (NTDs). It also explores how environmental alterations, including urbanization, water development projects, changes in agricultural practices, and natural disasters such as hurricanes, earthquakes, and tsunamis, can result in ecological changes that impact on the maintenance and spread of infectious diseases in a community. The known and potential effects of climate variation and global climate change on the natural history of vector-borne diseases such as dengue are discussed. Sustainable environmental intervention strategies to reduce the burden of infectious diseases will be considered for each of the major diseases covered in class. For example, the course will examine different ways in which mosquito borne diseases such as malaria and West Nile virus are controlled in developing and developed countries, and discuss the risk and benefits of pesticide application in both settings. Students will be able to apply what they have learned towards both evaluating the potential of certain environments or environmental practices to promote transmission of specific pathogens, and understanding the basis of strategies aimed at the remediation, prevention and control of environmentally-dependent pathogens. This course is appropriate for MPH students and undergraduates, especially those interested in biology, global health, and the environment.