History of coronavirus

For the ongoing outbreak, see 2019-20 Wuhan coronavirus outbreak. For the virus strain causing this outbreak, see 2019 novel coronavirus.
A coronavirus is one of a number of viruses that cause diseases in mammals and birds. In humans, the viruses cause respiratory infections, including the common cold, which are typically mild, though rarer forms such as SARS, MERS and COVID-19 can be lethal. Symptoms vary in other species: in chickens, they cause an upper respiratory disease, while in cows and pigs coronaviruses cause diarrhea. There are no vaccines or antiviral drugs to prevent or treat human coronavirus infections.
Coronaviruses comprise the subfamily Orthocoronavirinae in the family Coronaviridae, in the order Nidovirales.[5][6] They are enveloped viruses with a positive-sense single-stranded RNA genome and a nucleocapsid of helical symmetry. The genome size of coronaviruses ranges from approximately 26 to 32 kilobases, the largest among known RNA viruses. The name coronavirus is derived from the Latin corona, meaning "crown" or "halo", which refers to the characteristic appearance of the virus particles (virions): they have a fringe reminiscent of a crown or of a solar corona.
In 2019, an outbreak began in Wuhan, China, and is ongoing as of February 2020. As of 15 February it has affected over 66,000 people. Because of the virus's contagiousness, mortality rate, and resistance to treatment, it has prompted extensive government action including mandated quarantines. Internationally, countries have limited travel to and from affected regions and implemented screening measures to detect potential carriers of the virus.
Discovery
Coronaviruses were discovered in the 1960s.[7] The earliest ones discovered were infectious bronchitis virus in chickens and two viruses from the nasal cavities of human patients with the common cold that were subsequently named human coronavirus 229E and human coronavirus OC43.[8] Other members of this family have since been identified, including SARS-CoV in 2003, HCoV NL63 in 2004, HKU1 in 2005, MERS-CoV in 2012, and SARS-CoV-2 (formerly known as 2019-nCoV) in 2019; most of these have been involved in serious respiratory tract infections.
Transmission
Human to human transmission of coronaviruses is primarily thought to occur among close contacts via respiratory droplets generated by sneezing and coughing
Human coronaviruses
Coronaviruses are believed to cause a significant proportion of all common colds in adults and children.[11] Coronaviruses cause colds with major symptoms, such as fever and sore throat from swollen adenoids, primarily in the winter and early spring seasons.[24] Coronaviruses can cause pneumonia - either direct viral pneumonia or a secondary bacterial pneumonia - and may cause bronchitis - either direct viral bronchitis or a secondary bacterial bronchitis.[25] The much publicized human coronavirus discovered in 2003, SARS-CoV, which causes severe acute respiratory syndrome (SARS), has a unique pathogenesis because it causes both upper and lower respiratory tract infections.[25] There are no vaccines or antiviral drugs to prevent or treat human coronavirus infections.

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