Final answer:
Epidemiologists investigate disease transmission and develop public health policies to manage and prevent diseases. They collect data, interact with affected populations, and conduct rapid response to outbreaks.
Step-by-step explanation:
Epidemiologists play a crucial role in public health by focusing on the study of disease occurrence and distribution within populations. Two key roles they assume are: first, the investigation of disease transmission patterns to understand the spread of diseases geographically and over time. This involves gathering clinical records, interviewing patients, and surveilling disease outbreaks to identify the initial transmission method. Secondly, epidemiologists develop strategies and design public health policies aimed at reducing disease incidence and preventing further spread. They also respond to immediate threats by conducting rapid investigations during outbreaks, recommending control measures such as vaccinations and quarantine protocols.