An epidemiologist is an “investigator who studies the occurrence of disease or other health related conditions or events in defined populations.” (Last, 2001) Epidemiologists in this enumeration include all those employed by the state who are either federal assignees, contract employees, fellows or state employees assigned to work at a local or regional level.

Reference: Last, J. M. (Ed.) (2001). A Dictionary of Epidemiology (4 ed.). New York, NY: Oxford University Press, Inc.