Микобактериальные заболевания
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ISSN: 2161-1068
ISSN: 2161-1068
Saru Maharjan
Corona viruses are enveloped viruses with a positive-sense single-stranded RNA genome. It is roughly spherical in shape having a diameter of around 125 nm. The genome size of coronaviruses ranges from 26.4 to 31.7 kilobases and is counted as one of the largest RNA viruses. The first human coronavirus was discovered in 1960s, since then coronavirus family gained notoriety with the emergence of severe acute respiratory syndrome (SARS). In 2002/2003, SARS-CoV was identified that lasted for 8 months and resulted in 8,098 confirmed human cases worldwide, of which 774 were lethal. In 2013, MERS-CoV (Middle East Respiratory Syndrome) appeared in kingdom of Saudi Arabia that continued to cause outbreak resulting in 2,260 affirmed cases in 27 countries of which 803 were fatal. In 2019, a global pandemic of SARS-CoV-2 (Severe Associated Respiratory Syndrome Coronavirus-2) was identified which resulted in 29,466,633 confirmed cases in more than 250 countries and 933,150 have been fatal. SARS-CoV-2 symptoms are milder, yet it is highly transmissible infectious diseases compared to SARS and MERS outbreaks, according to morbidity and mortality rates. Genome sequencing and phylogenetic analysis provide powerful insights into the origins, transmission, and evolution of emerging viral infections such as SARS-CoV-2.