The emerging SARS-CoV, MERS-CoV, and SARS-CoV-2: An insight into the viruses zoonotic aspects

Abstract

Zoonotic coronavirus disease (COVID) has emerged in the past two decades and caused a pandemic that has produced a significant universal health alarm. Severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome-CoV (MERS-CoV) emerged in 2002 and 2012, respectively, provoking severe lower respiratory infection and deadly pneumonia. COVID-19 is a severe respiratory disease caused by the new strain of novel CoV (SARS-CoV-2). The zoonotic aspects of the SARS-CoV-2 in comparison to SARS-CoV and MERS-CoV are highlighted in this article. COVID-19 has rapidly become a pandemic and has spread and infected millions of people worldwide. As of November 19, 2020, the date of submitting this review, the total CoV cases, deaths, and recovered patients are 56,828,218, 1,359,320, and 39,548,923, respectively. In conclusion, COVID-19 has particularly altered the opinion of the significance of zoonotic diseases and their animal origins and the intermediate reservoirs, which may be unknown wild animals. Genetically, the SARS-CoV-2 is related to the SARS-like bat CoVs and shares 85% identity with the SARS-CoV that is derived from the SARS-like bat CoVs. However, the virus is related to a lesser extent to the MERS-CoV. The SARS-CoV-2 uses the same receptor-binding domain receptor of the SARS-CoV - the angiotensin-converting enzyme 2; conversely, DPP4 (CD26). It has not been proved that the MERS-CoVs primary receptor is the receptor of the SARS-CoV-2.

Keywords: Bats; RNA viruses; coronavirus disease-19; pneumonia; zoonotic.

Figure-1

The well-adapted strains of coronaviruses from humans.

Figure-2

Briefing of severe acute respiratory syndrome coronavirus transmission pathways.

Figure-3

Briefing of Middle East respiratory syndrome-coronavirus transmission routes. Solid lines designate identified transmission pathways and dashed lines designate possible transmission routes for which supporting proof is incomplete or indefinite.

Figure-4

Briefing of severe acute respiratory syndrome coronavirus-2 transmission routes. The solid lines designate identified transmission pathways and the dashed lines designate the possible transmission routes for which supporting proof is incomplete or indefinite.