ABSTRACT
This chapter discusses the epidemiology of outbreak investigations. It presents the importance of case definitions, and the various types of epidemic curves. Geographical information systems methods might be very useful to study rabies in racoons or factors influencing tick-borne encephalitis virus prevalence in ticks, since neither animal moves around very much, but humans can travel quickly over large distances. The geography shows the different age groups going up and the number of cases in each group as squares going left and right. The disease was gastroenteritis, and there was a rather prolonged epidemic. The geographical difference could be due to increased clinical awareness in the doctors on the east side of the river. For diseases that are not only due to environmental exposures but that also spread person-to-person, the analysis of an outbreak often becomes complicated.
