| T13 |
0-2011 |
Sentence |
denotes |
Coronaviruses (CoVs) have a single-stranded RNA genome (size range between 26.2 and 31.7 kb, positive sense), covered by an enveloped structure.[1] The shape is either pleomorphic or spherical, and it is characterized by bears club-shaped projections of glycoproteins on its surface (diameter 80–120 nm).[1] Among all the RNA viruses, the RNA genome of CoV is one among the largest.[2] The number of open reading frames (ORFs) in the CoV genome ranges from six to ten.[2] CoV genetic material is susceptible for frequent recombination process, which can give rise to new strains with alteration in virulence.[3] There are seven strains of human CoVs, which include 229E, NL63, OC43, HKU1, Middle East respiratory syndrome (MERS)-CoV, severe acute respiratory syndrome (SARS)-CoV, and 2019-novel coronavirus (nCoV), responsible for the infection with special reference to the involvement of the respiratory tract (both lower and upper respiratory tract), e.g., common cold, pneumonia, bronchiolitis, rhinitis, pharyngitis, sinusitis, and other system symptoms such as occasional watery and diarrhea.[45] Among these seven strains, three strains proved to be highly pathogenic (SARS-CoV, MERS-CoV, and 2019-nCoV), which caused endemic of severe CoV disease.[5] The reservoir of SARS-CoV is unknown, but bats and subsequent spread to Himalayan palm civets are hypothesized.[6] MERS-CoV also has a zoonotic origin in the Middle East, and the transmission is through camels.[7] Among these, the SARS-CoV outbreak started in 2003 in Guangdong province of China and the second outbreak of the MERS-CoV outbreak in 2012 in Saudi Arabia.[146] Previous to these two attacks, CoV was known to cause milder disease, and these two outbreaks highlighted their adaptive potential to the changing environmental conditions and they are classified under “emerging viruses.” Knowledge about the structure, metabolic pathways of CoV, and pathophysiology of CoV-associated diseases is important to identify possible drug targets.[8] |
