Virology and Molecular Pathogenesis of Coronavirus Disease 2019: An Update.

The pandemic coronavirus disease 2019 outbreak's causative agent was identified as severe acute respiratory syndrome coronavirus 2. It is a positive-sense single-stranded RNA virus with a ~30 kb size genome that belongs to the Nidovirales. Molecular analysis revealed that severe acute respiratory syndrome coronavirus 2 is a variant of severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome coronavirus with some sequence similarity. The confirmed cases and death toll are high in severe acute respiratory syndrome coronavirus 2 compared to severe acute respiratory syndrome coronavirus and the estimated R0 is >1. The data on pathological findings on severe acute respiratory syndrome coronavirus 2 are scarce and present treatment management is based on symptoms that are similar to severe acute respiratory syndrome coronavirus. In this review, we have discussed the transmission, viral replication, and cytokine storm and highlighted the recent pathological findings of coronavirus disease 2019. The reported severe acute respiratory syndrome coronavirus 2 pathological findings were similar to that of severe acute respiratory syndrome coronavirus. Though these findings help notify the clinical course of the disease, it warrants further in vivo and ex vivo studies with larger samples obtained from the coronavirus disease 2019 patients.