An epidemic refers to a sudden increase in the number of cases of a disease above what is normally expected in a specific area. This can occur with various diseases, such as influenza or COVID-19, and often requires public health interventions to control its spread. Epidemics can have significant social and economic impacts, leading to increased healthcare costs and disruptions in daily life. Understanding the patterns and causes of epidemics is crucial for epidemiologists and public health officials to implement effective prevention and response strategies.