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 complications 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% identical). 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.