A narrative review comparing SARS-CoV-2, SARS-CoV-1 and MERS-CoV highlighting their characteristic features, evolution and clinical outcomes

Abstract

COVID‑19 pandemic caused by SARS-CoV-2 created a bio threat situation throughout the world. This article features evolution and clinical outcomes of SARS-CoV-2, SARS-CoV-1 and MERS-CoV. COVID‑19 originated in Wuhan, China and resulted in severe morbidity and mortality. Features of SARS are similar to COVID‑19. MERS exhibited a relatively milder disease, mainly in Middle East countries. Coronaviruses are large (100 nm) viruses exhibiting a spherical shape with a lipoprotein envelope and can cause diseases in animals and humans. All coronaviruses are sensitive to physicochemical agents. They attach to angiotensin Converting Enzyme -2 (ACE-2) and serine protease receptors of lungs. Literature review and genetic homology were conducted using data sources and bioinformatics tools for the comparison of SARSCoV- 2 with SARS-CoV-1 and MERS-CoV. Genome analysis between SARS-CoV-2 with SARS-CoV-1 and MERS-CoV revealed that SARS-CoV-2 and SARS-CoV-1 are 95% related with each other whereas SARS-CoV-2 and MERS-CoV are 65% related. SARS-CoV-2 and SARS-CoV-1 are genetically more related than MERS-CoV. Animal reservoirs for SARS-CoV-2 and SARS-CoV-1 may be bats, pangolins, etc. MERS can be transmitted from infected camels. SARS-CoV-2 might have evolved from SARS-CoV-1 or from another animal reservoir coronavirus. It can be transmitted from infected animals and humans through respiratory route. Strict public health measures such as physical distancing and maintaining good hygiene should be taken to contain their community spread. SARS-CoV-2 can undergo antigenic variation resulting in difficulty to develop drugs and vaccines. COVID‑19 has caused a severe blow to the economy of both developed and developing nations.