The new novel coronavirus disease 2019 (COVID-19) has caused havoc across the globe. United, the world is fighting against the pandemic since its first outbreak in Wuhan, China in December 2019. Possible animal sources of COVID-19 have not yet been confirmed. But did you know coronaviruses are not the new viruses. They have a history of about 9 decades since its evolution first came into existence.
Coronaviruses were first discovered in the 1930s with an acute respiratory infection in domesticated chickens.1 These are well-established pathogens of humans and animals from the virus family Coronaviridae.2 Human coronaviruses were discovered in the 1960s. The earliest ones studied were from human patients with the common cold, which were later named human coronavirus 229E and human coronavirus OC43. These virus displayed a characteristic fringe of large, distinctive, petal-shaped spikes which resembled a crown, hence the name “Coronavirus”.3 Coronaviruses are large, enveloped, positive-stranded RNA viruses. They have the largest genome among all RNA viruses, typically ranging from 27 to 32 kb.4
Coronavirus can be classified into four genera:
Among them, alpha- and betacoronaviruses infect mammals, gammacoronaviruses infect avian species, and deltacoronaviruses infect both mammalian and avian species.4
Coronaviruses common symptoms include fever, cough, fatigue, cold and upper respiratory tract infections throughout the world, in all age groups.6,7
Discoveries of Human Coronaviruses8-10
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HCoV, Human Coronavirus; SARS-CoV, Severe acute respiratory syndrome coronavirus; MERS-CoV, Middle East respiratory syndrome-related coronavirus; COVID-19, Coronavirus disease 2019; SARS-CoV-2, Severe acute respiratory syndrome coronavirus 2.
Many human coronavirus have their origin in bats. The HCoV NL63 and HCoV 229E shared a common ancestor with bat coronavirus. Occasionally, people get infected with these viruses which may then spread to other people. For example, SARS-CoV first infected in bats and then associated with civet cats which spread to humans and MERS-CoV emerged in humans from bats through intermediate host of dromedary camels.7
2. J.S.M. Peiris. Coronaviruses. (Eighteenth Edition), 2012.
3. Sturman, L. S. The Molecular Biology of Coronaviruses. 1983.
4. Fang Li. Structure, Function, and Evolution of Coronavirus Spike Proteins. 2016.
5. Stephen N.J. Human coronaviruses. 2012.
8. Jeffrey S. Kahn. History and Recent Advances in Coronavirus Discovery. 2005.
10. Stanley Perlman and Kenneth McIntosh. Coronaviruses, Including Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). 2020.
COVID-19 has been a great lesson to mankind across the globe in practicing personal hygiene and keeping the surroundings clean. Till date, there is no fixed treatment for this dreadful virus. Social distancing and few simple safety precautions are being followed. Further on safety measures to be taken during pandemic, read this space in our next blog. Read here>