Coronaviruses outbreaks — then to now

Abstract

According to the World Health Organization (WHO), Viral diseases continue to evolve, posing a significant public health concern. Over two decades, several viral epidemics have been recorded wherein several strains of coronaviruses have been associated with epidemics causing severe respiratory complica-tions and even death. Recently, a novel strain of this virus has come into the picture, eventually leading the world towards a pandemic. The situation today is similar to that witnessed earlier named as “SARS-CoV” and “MERS-CoV” which also affected the respiratory system. Current evidence suggests that SARS-CoV-2 is propagating to humans via transmission from illegally sold wild animals in the Huanan Seafood Wholesale Market. Phylogenetically, it has been shown that SARS-CoV-2 is a new member of the Coronaviridae family and yet is distinct from SARS-CoV (79% identical) and MERS-CoV (50% iden-tical). Knowing the origin of such a pathogen is essential to develop the means to prevent further transmission and effective vaccines. This starts a discussion about the very origin of these viruses that have fanned a global emergency in the name of COVID-19. Therefore, the focus of this review is the origin, evolution and emergence of CoV during “SARS-CoV”, “MERS-CoV” and “SARS-CoV-2” along with possibilities of future outbreaks.