An epidemic is a sudden increase in the number of cases of a disease within a specific geographic area or population. It occurs when a contagious disease spreads rapidly, affecting many individuals at once. Common examples of epidemics include outbreaks of the flu or measles in communities. Epidemics can be caused by various factors, including changes in the environment, increased human interaction, or the emergence of new pathogens. Public health measures, such as vaccination and sanitation, are often implemented to control the spread of diseases during an epidemic and protect the health of the population.