Severe acute respiratory syndrome-Coronavirus 2 (SARS-CoV-2) is a novel virus from the family of coronaviruses which causes COVID-19 i.e. Coronavirus Disease-2019. It is the successor of the SARS-CoV-1 which caused the SARS outbreak in the year 2003-2004. This is a positive-sense single-stranded RNA virus which has rapid mutation properties.
The etymology of the name suggests that 'Corona' comes from the Latin word corōna meaning crown, garland, or a wreath. When seen under an Electron Microscope, the virion which has a diameter of 50-200 nanometres looks like the solar corona hence named Coronavirus.
When the virus enters the body; it attaches itself to the binding site or the ACE 2 receptors of healthy lung cells through its spike protein. Then it enters the cell via this attachment and causes apoptosis or cell death. The virus also affects organs other than lungs such as the brain, heart and kidneys. The multiple impact points make it problematic for the researchers to create a vaccine in addition to its rapid mutation properties.
The disease might have a zoonotic origin i.e. the transmission occurs from animals to humans. On comparing the genomic sequences the Human Coronavirus strain is found to be 96% identical to Bat Coronavirus samples and 92% similar to the Pangolins samples. Human transmission of the disease takes place via air droplets when the infected person is coughing, sneezing or talking.
The first cases of this respiratory illness were reported to the World Health Organization (WHO) from Wuhan City, Hubei Province, China, on 31 December 2019. It is the first severe outbreak since the 2009 H1N1 Influenza Pandemic. Initially, it was supposed that the site of origination is Huanan Seafood Wholesale Market but, in May 2020 the negative samples tested, by Chinese Center for Disease Control and Prevention, from the livestock market suggested that it was the site of the super spreading of the virus.
SARS-CoV-2 is known to have an average reproduction number of 2.2-2.6 which means that, on an average, one infected person can spread the infection to 2-3 people. Although if measures like social distancing are put into use, to reduce the exposure of the infected population, it leads to a significant reduction in transmission rates. The infection fatality rate (IFR) of COVID-19 in various studies till 16th June 2020 was projected to range 0.60% to 1% of infected people . However few studies suggested the IFR as high as 3.6%.
The testing of an individual takes place through a method known as real-time Reverse transcription Polymerization Chain reaction (rRT-PCR). The process of obtaining strains and testing the patients usually involves nasal swabs or sputum swabs; the results come in within a span of a few hours to a couple of days.
Currently, there are no known vaccines available for the virus or any specific antiviral treatments, but there are numerous vaccines in works all over the world to tackle COVID-19. Experts believe that the minimum time required to test a vaccine is 12 to 18 months.
Trials are also going on for the repurposed drugs or the drugs which are useful for treating other diseases and might be capable against COVID-19: Some of these drugs are Hydroxychloroquine, chloroquine, Remdesivir, Dexamethasone, Lopinavir-ritonavir, and Convalescent plasma.
The only current solutions for tackling the pandemic are social distancing, hand wash, hygiene and face masks.
