An outbreak of severe pneumonia of unknown cause was reported in December 2019 in Wuhan, Hubei Province, China. The infectious virus was soon identified and named as 2019 novel coronavirus (2019-nCov). The name of the coronavirus infectious disease (COVID-19) was given by WHO on 11 February 2020. It has so far caused about 118 000 cases in 114 countries including China and was characterized as a pandemic by WHO on 11 March. We still face great challenges in control of the epidemic: uncertain initial source of infection, infected populations widely scattered, complex routs of transmission, populations generally susceptible, high contagiousness of the virus, and finally vaccines unlikely available in the near future.