Epidemiologists are scientists who study epidemics. You may be surprised to learn that equally important wSork is done in the field as in the lab. To trace an outbreak to its source and identify the microbe that causes it, epidemiologists often start by interviewing the people stricken with the disease. Their goal is to find common links between these people and the ways the disease has spread.

They also take samples from anything that might contain microbes relating to the outbreak—from blood and local insects to food and water. Steps taken to investigate and control an outbreak may effect new public health measures or focus attention on a previously unknown microbe. Perhaps most importantly, these techniques help prevent similar outbreaks in the future.