![]() ![]() Laboratory diagnosis is essential for effective management and epidemiology of COVID-19 as it serves as a supplementary tool to ascertain not only case identification and treatment but also aids in the contact tracing, finding the animal source and rationalization of control and preventive measures along with the containment of the disease. Detection methods should be highly sensitive, rapid, cost-effective, and specific. As evidenced by previous epidemics caused by SARS-CoV and MERS-CoV, diagnosis is the most important point in the COVID-19 management not only for the safety of infected individuals but also for the community/population safety as well. Within 3 months of the appearance of the first case (17 November 2019), on 30 January 2020, COVID-19 was declared as a public health emergency of international concern by the WHO and on 11 March 2020, COVID-19 got categorized as a pandemic. Zoonotic origin of human SARS coronaviruses From cross-species analysis, animal species such as Minks, ferrets, snakes, turtles, yak, pigs are presumed to be the potential intermediate host between bats and humans. However, the absence of an insertion of four residues motif ‘PRRA’ in the viral genome of pangolin coronaviruses indicates the contrary. Initially, Pangolins were considered as the most probable intermediate host of SARS-CoV-2 due to the high sequence similarity between the two coronaviruses (pangolin coronavirus and novel hCoV). There is still a lot of ambiguity related to the identity of the intermediate host responsible for the transmission of SARS-CoV-2 to humans. SARS-CoV and MERS-CoV were transmitted to humans from bats through civet cats and dromedary camels, respectively ( Figure 1). It was also found to be closely related to bat-SL-CoVZC45 and bat-SL-CoVZXC21, the bat-derived SARS-like coronaviruses. The genomic sequence of SARS-CoV-2 shares 79% homology to SARS-CoV and 50% to MERS-CoV. This novel coronavirus or SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) is a beta-CoV and through phylogenetic analysis has been placed under the subgenus Sarbecovirus. The causal agent was found out to be a novel coronavirus. It was initially speculated that till October 2020, about 10% of the world population may have gotten infected, which now looks like an overestimate as till Dec 2020 about 1% population got infected and this proved to be saving grace for the mankind. Many countries in Europe, North and South America, and Africa continue to report a high incidence of daily new cases and are reinstating lockdown procedures. The newly detected variants of the virus (SARS-CoV-2 VUI-202012/01 UK strain and 501Y.V2 South African strain) are highly transmissible resulting in a spike in the number of COVID-19 cases. There have been 82 million confirmed cases of coronavirus, 1.79 million deaths and around 4,44,437 cases are reported everyday world over, as of 30 December 2020. The number of cases grew rapidly across the region, ultimately disseminating to 183 countries and 27 territories globally within a short span of around 6 months leading to a full-blown pandemic. ![]() In December 2019, cases of enigmatic disease leading to pneumonia in infected individuals of unknown etiology were reported in Wuhan City, Hubei Province of China. ![]()
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