The novelist Paulo Coelho once wrote that 'Everything that happens twice will surely happen a third time'. While our memory of the fatal severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) has not faded, a third, novel coronavirus (2019-nCoV) is coming into the spotlight. 

The host range expansion of coronaviruses (CoVs) from wildlife to humans via genetic recombination and/or mutations on the receptor-binding domain in the spike (S) gene is well established and results in several diseases with high fatality rates, such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS)

Increases in the global mobility of humans, nonhuman animals, plants, and products are driving the introduction of infectious diseases to new locations. In recent years we have witnessed several infectious diseases spread well beyond their previously understood geographic boundaries, as was demonstrated by the introduction of Zika virus to the Americas.