Abstract

THE PROXIMAL ORIGIN OF COVID-19

Dr. Ripudaman M. Singh*, Osama Chaudhary, Taimoor Ansari, Areeb Khan, Zaid Khan and Anas Khan

ABSTRACT

As of February 15, 2020, 51,800 cases of COVID-19 disease, including more than 1,600 COVID-19-related deaths, had been Laboratory-confirmed in mainland China, mainly in Hubei province. Additionally, 526 laboratory-confirmed cases have been reported across 25 other countries. Approximately, 15% of cases reported to the World Health Organization (WHO) are severe, 3% are critical, and 82% are mild clinical manifestations, whereas the estimated overall case fatality rate is approximately 2% but the figure outside of Hubei province is approximately 0.05% or less, not different from the fatality identified in the seasonal influenza. It is not yet clear why sustained chains of transmission have not been reported outside Asia. Genetic factors encouraging transmission within Asian populations, effective containment, inefficient transmission, poor reporting due to lacking molecular testing capacity in some low-income countries, and specific environmental conditions in Hubei province and mainland China. Among the most severely affected patients, viral ribonucleic acid (RNA) has been detected in the plasma approximately 15% and viral detection in stool reveals possibility of fecal transmission. The unanswered questions include the pathophysiology of pulmonary clinical. Infection, influenza and other viral co-infection, and the rate of bacterial complications. Six residuals in the Receptor Binding Domain (RBD) of the spike protein of SARS-CoV and SARS-related coronaviruses, the most variable part of the virus genome appear to be critical for binding to the human ACE2 receptor and the determining host range. Five of these six residuals are mutated in COVID-19 compared to its most closely related virus, RaTG13 sampled from a Rhinolophus affinis bat to which it is approximately 96% identical. Volz., et al. used Bayesian and maximum likelihood phylogenetic methods on analyzing 53 SARS-CoV-2 (COVID-19) Whole genome sequences collected up to February 3, 2020 revealed that the COVID-19 was introduced into the human population in Wuhan, China in early December 2019 and has an epidemic doubling time of about 7 days. In conclusion, to identify the COVID-19 origin, obtaining virus sequences from immediate non-human animal sources would be the most definite method. For substantially refining of phylogenetic estimates of epidemic size and growth rate of COVID-19 in Wuhan, Hubei province and mainland China, larger numbers of more systematically sampled sequences from across China are needed. (Attapon et al,. 2020).

Keywords: COVID-19; 2019-nCoV; SARS-CoV-2; Proximal Origin; Phylogenetic, Coronavirus Disease 2019, MERS: Middle-East Respiratory Syndrome, ACE: Angiotensin-Converting Enzyme, WHO: World Health Organization.