The emergence of SARS, MERS and Novel SARS-2 coronaviruses in the 21st century

At the beginning of the 21st century, a new deadly infectious disease known as severe acute respiratory syndrome (SARS) was recognized as a global public health threat. Subsequently, ten years after the initial SARS cases occurred in 2002, new cases of another atypical respiratory disease caused worldwide concern. This disease became known as Middle East respiratory syndrome (MERS). Currently, history has repeated itself with the emergence of a new Chinese epidemic at the end of 2019.