Genetics of Severe Acute Respiratory Syndrome Coronavirus-2 and Diagnosis of Coronavirus Disease-2019: An Overview

Abstract

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a positive sense, single-stranded RNA virus, responsible for the ‘coronavirus disease-2019’ (COVID-19) pandemic. SARS-CoV-2 belongs to the sarbecovirus (lineage-B) sub-genus within the betacoronavirus genus of the coronaviridae family. SARS-CoV-2 shares similarities with SARS-CoV, which was responsible for the 2003 SARS epidemic. SARS-CoV-2 binds with great affinity to the Angiotensin Converting Enzyme-2 receptors on human cells, and its ~30 kilobases long RNA genome hijacks the host machinery and compromises the host immune system with the help of accessory proteins, such as non-structural proteins, resulting in a widespread infection. The spike protein is responsible for the contagious nature of SARS-CoV-2 and, together with the nucleocapsid protein, elicits the host inflammatory response. Several real-time reverse transcriptase polymerase chain reaction (rRT-PCR) tests have been developed to confirm SARS-CoV-2 infection in suspected cases of COVID-19. Furthermore, rapid tests based on SARS-CoV-2-specific antigens and antibodies have been developed to conduct epidemiological surveillance of the hotspot regions that are worst affected by the COVID-19 pandemic. Until effective measures to prevent the occurrence or spread of COVID-19 pandemic are developed, containment measures are being taken, such as isolation of confirmed COVID-19 patients, quarantine of individuals who may have come in contact with a SARS-CoV-2 infected individual, community-wide social distancing, state/nation-wide lockdown, etc. Several vaccines and drugs are being tested that could target the viral structural proteins, non-structural proteins or associated SARS-CoV-2 sub-genomic RNA regions.