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CovidReference.com
novel SARS-CoV and MERS-CoV. There is strong evidence that these viruses emerged recently from animal reservoirs, originating in bats and transmitted to man via intermediate host species. Intra- and inter-species transmission of CoVs, and genetic recombination events contribute to the emergence of new CoV strains. The following sections will review CoV in general with a more detailed appraisal of the origin, evolution, virological structure and pathogenesis of SARS-CoV-2 to expand knowledge pertaining to COVID-19 and prospective anti-viral and vaccine therapies.
History Coronavirus disease was first described as early as 1930 presenting as infectious bronchitis in chickens, gastroenteritis in pigs and severe hepatitis and neurological disease in mice. The first coronavirus to be isolated was the Infectious bronchitis virus (IBV) from chickens with respiratory disease reported by Beaudette and Hudson in 1937 (Zuckerman 2009, Korsman 2012, Knipe 2013). The first human coronaviruses were discovered much later. In 1965, Tyrrell and Bynoe isolated a virus, which they designated B814, from a respiratory tract sample of a boy with a common cold by passage in embryonic tracheal organ cultures (Zuckerman 2009). At the same time, Hamre and Procknow were able to grow a virus, designated 229E, in tissue culture from samples obtained from medical students with upper respiratory tract infections. These two viruses were both ether-sensitive, shared identical morphology under electron microscope, and were not related to any known human viruses. Furthermore, B814 resembled avian IBV suggesting a similar origin (Perlman 2020, Kahn 2005). Following similar techniques of tissue culture, English scientist McIntosh and colleagues recovered multiple isolates of previously unknown pathogenic agents from human respiratory tract samples. The human viral prototype was designated OC43 indicating it was grown in organ culture (Perlman 2020, Kahn 2005). OC43 morphologically resembled two animal CoV, mouse hepatitis virus and transmissible gastroenteritis virus of swine. The unique feature were the distinct protruding spike proteins present on the viral surface reminiscent of a crown. This group of unrecognized viruses was thus named “Coronaviridae” which received and accepted by the International Committee for the Taxonomy of Viruses (ICTV) in 1968,. (Perlman 2020, Kahn 2005, Almeida 1968). In November of 2002 an unusual and lethal form of pneumonia, termed severe acute respiratory syndrome (SARS), emerged in Guangdong province, PeoKamps – Hoffmann
