Insights into the cross-species evolution of 2019 novel coronavirus.

Recent study reported in this journal that the threats of continuous evolution and dissemination of 2019 human coronaviruses.1 Since its emergence in December 2019, a “seventh” member of the family of 2019 human coronavirus named “SARS-CoV-2” was responsible for an outbreak of coronavirus disease (COVID-19) in Wuhan, China.2 As of February 23, 2020, China had reported more than 77,042 confirmed cases of SARS-CoV-2, with 2,445 fatalities and counting (http://www.nhc.gov.cn). Strikingly, SARS-CoV-2 had been transmitted rapidly in more than 29 countries to date (https://www.who.int), including Asia, Europe, North America, Africa, and Oceania, posing serious concerns about its pandemic potential. Despite of droplet and contact transmissions of SARS-CoV-2, recent studies demonstrated that SARS-CoV-2 might be transmitted via aerosol and fecal–oral routes 3 (Figure 1), which needs to be paid attention in particular.