Emerging threats from zoonotic coronaviruses-from SARS and MERS to 2019-nCoV

Coronaviruses are enveloped RNA viruses that are widely detected in mammals and birds, and commonly denoted in etiologies of upper respiratory tract infections in humans.1e3 Two potentially dangerous zoonotic coronaviruses have emerged in the past two decades.The severe acute respiratory syndrome coronavirus (SARS-CoV), originating from China, was responsible for the first outbreak that extended from 2002 to 2003.The second outbreak occurred in 2012 in the Middle East and was caused by the Middle East respiratory syndrome coronavirus (MERS-CoV).1e4 A new strain of coronavirus, designated as the 2019 novel coronavirus (2019-nCoV), emerged during the third outbreak in Wuhan, China, at the end of 2019. 5Symptoms of pneumonia with unknown etiology were reported in several patients.The infection was epidemiologically linked to the Huanan seafood market in Wuhan. 6Similar to the SARS-CoV and the MERS-CoV, bats have been denoted as