What branch of medical science studies diseases affecting large populations?

Epidemiology is the branch of medical science that focuses on the study of how diseases affect large groups of people. It involves analyzing the patterns, causes, and effects of health and disease conditions in defined populations. Epidemiologists use statistical methods to identify risk factors for disease and targets for preventive healthcare. By studying outbreaks and the spread of diseases, they play a crucial role in public health, helping inform policy decisions and health guidelines aimed at improving community health. This field is essential for managing and controlling diseases, particularly during outbreaks, by recognizing trends and implementing strategies to mitigate impact.

The other fields mentioned, while important in their own right, focus on different aspects of biology and medicine. Immunology deals with the immune system and its responses to pathogens; pathology studies the nature of disease, including causes and effects on tissues; and bacteriology specifically involves the study of bacteria and their relationships to diseases. These areas do not primarily analyze diseases at the population level in the way epidemiology does.