Nester's Microbiology 8th Edition by Denise Anderson,Sarah Salm,Deborah Allen

Exercise 1

A student disagreed with the presentation of the examples in figure 19.9. She claimed that the number of cases from a common-source outbreak could remain high over a much longer period of time in some cases and not decrease to zero. Is the student's claim reasonable? Why or why not?

FIGURE 19.9 Comparison of Propagated Versus Common-Source Epidemics (a) The time between the index case and subsequent cases reflects the average incubation period of the disease. As the disease is propagated, this interval is blurred. (b) Cases in a common-source epidemic appear only within the incubation period.