If an epidemic curve shows multiple peaks separated by intervals, this pattern most likely indicates:

• A. A propagated outbreak with successive generations
• B. A point-source single-exposure outbreak
• C. No transmission
• D. Random reporting

Answer: (C)

The main idea is that the shape of an epidemic curve tells you how the disease is spreading. When you see several peaks separated by intervals, it points to propagated spread with successive generations of transmission. Each peak marks a new wave of cases after the previous generation has infected others and those new cases progress through the incubation period to onset. The time between peaks roughly reflects the generation time (the time from a person’s infection to the infections they cause). This pattern is different from a point-source outbreak, where a single exposure leads to a rapid rise and then a fall as the exposed population is finished, producing one main peak rather than multiple waves. No transmission would show little to no cases, not repeating peaks. Random reporting might blur the curve but wouldn’t generate clear, regular waves.