Question

What is the difference between common/single source vs. propagated types of outbreaks?

A) Common source outbreaks involve a single contaminated source, while propagated outbreaks involve multiple sources.
B) Common source outbreaks spread through direct person-to-person transmission, while propagated outbreaks involve exposure to a common source.
C) Common source outbreaks have a longer incubation period, while propagated outbreaks have a shorter incubation period.
D) Common source outbreaks are caused by bacteria, while propagated outbreaks are caused by viruses.

Answer 1

Common source outbreaks are traced to a single source, while propagated outbreaks spread via person-to-person contact, with each case potentially starting new chains of transmission.

Step-by-step explanation:

The difference between common/single source and propagated types of outbreaks is that a common source outbreak involves all infected individuals getting the disease from a specific, single source, whereas a propagated outbreak results from direct or indirect person-to-person transmission, with each infected individual becoming a source themselves. An example of a common source outbreak can be traced back to John Snow's study, which identified a contaminated well as the source during a cholera outbreak. Conversely, propagated outbreaks, such as those caused by influenza, tend to have a longer duration, spreading through the population as people infect each other over time. The correct answer to the student's question is 'A) Common source outbreaks involve a single contaminated source, while propagated outbreaks involve multiple sources.'