A review of coronaviruses focusing on SARS-CoV-2 (2019-nCoV) the cause of COVID-19

Coronaviruses, enveloped positive single-stranded RNA viruses, have become significant pathogens for humans and other vertebrates since the outbreak of SARS (severe acute respiratory syndrome) in 2002 in China. These viruses could infect the respiratory tract of humans and other animals. The outbreaks of SARS and MERS (Middle East respiratory syndrome), which Bats are thought to be the origin of both viruses, have demonstrated that these viruses could be transmitted from animal to human and human to human. The rapid and widespread outbreak of pneumonia caused by SARS-CoV-2, since December 2019 worldwide, and its 2 to 3 percent mortality, indicates the serious threat of coronavirus to global health. Some coronaviruses also cause great economic loss by infecting domestic animals. At the current time, there is no definitive treatment or effective vaccine for COVID-19, a disease caused by SARS-CoV-2. So it is necessary to develop effective treatment and prevention methods to combat coronaviruses.