This section introduces some key epidemiological terminology and an overview of the COVID 19 outbreak history and its geographic distribution.  

An epidemic is the occurrence of cases of an infectious disease that is over what is usually expected. To determine what is 'normally expected,' the number of cases of disease that occur in a specific population over a specific period is needed, and the existence of an epidemic is judged relative to these statistics. Where excess disease cases above normal levels occur in a defined geographical area, such as a particular community or village, the term ‘outbreak’ is often used.

In the case of COVID 19 disease, cases are not reported under' normal' circumstances, so even a few cases arising would be unexpected and thus considered an outbreak. The situation can be different with other diseases, for example, Malaria, which occurs naturally in low levels in the populations of many tropical countries, with peaks during the rainy season. This cycle with seasonal peaks is expected and occurs year on year, and so would not be considered an outbreak.