In your opinion, which person was the most influential, or what event was signif

In your opinion, which person was the most influential, or what event was significant, in developing the new trends of Epidemiology? Please elaborate on your answer and include at least 2 scholarly references.
Textbook(s):
Fleming, S. T. (2008). Managerial epidemiology: Concepts and cases (3rd ed.). Chicago, IL:
Health Administration Press. ISBN 13: 978-1-56793-684-1