When the answer is "We don't know," epidemiologists get to work.

Reduce risk by uncovering clues about what causes disease and injury to better detect, plan for and prevent them - here and across the globe.

As an epidemiologist, you may investigate why and how diseases such as influenza occur in different groups of people, how to reduce the rate of heart disease in older adults, and now to best prepare for and reduce the impact on human health from a disaster.

What you learn may also be used to improve clinical and medical research and preventive health care.