2020 has seen a pandemic of a new virus known as coronavirus but it’s actually a new virus from the coronavirus family and it’s known as COVID 19 and SARS-COV-2. Some people understand that this is the first time such a virus outbreak has happened but in reality, there have been previous outbreaks with outbreak of SARS in 2002 and outbreak of MERS in 2012. Both these viruses belong to the coronavirus family. In fact there are seven viruses in this family that can and have attacked humans. Just like any other virus from coronavirus family, SARS when attacks a human causes multiple symptoms i.e. cough, sneezing, running nose, sore throat and fever. Most of the time, these are just mild symptoms and they can be controlled with regular antibiotic and over the counter medicine. On the other hand, if the attack is severe or critical, SARS virus can enter in human lungs and seriously damage the air sacks and inner tissues of the lungs. This condition is called Severe Acute Respiratory Syndrome or SARS. If the patient is attacked critically, it can immediately shut down the lungs and the patient might needs to go on ventilator.
History and origin of SARS:
SARS was first seen in 2002 somewhere in China where two patients were admitted in hospital with almost similar symptoms. SARS is thought to be important because of its highest mortality rate being the first major disease of 2000 millennium. From the moment it was first recognized, this virus outbreak affected more than 8000 people and around 800 died. In the beginning, this virus was identified by a WHO scientist from Vietnam. Unfortunately this scientist who told the world about the outbreak of a new type of virus on which antiviral and antibiotic medicines weren’t making any impact died because of the same disease. This lead to WHO declaring a worldwide alert for the spread of SARS virus and soon there were cases reported from China, Germany, Canada and even USA.
Structure of SARS:
There are basically three groups of viruses in coronavirus family; alpha, beta and gamma and even if the members of these groups differ in some features and characteristics, they all have the same structure i.e. spike glycoprotein, nucleocapsid protein, envelope protein and membrane protein. It is important to understand that although structure of SARS indicates it’s relation to the 2nd group of corona viruses, there are also some features that differentiate it and make it fell into a new group that has new and some similar features with other groups. N protein is crucial for virus RNA synthesis where the spike glycoprotein is responsible for latching on to human cells and penetrating it to replicate. RNA of SARS is arranged in 13 to 15 ORF or open reading frames and there are more than 30,000 nucleotides within a single RNA of SARS.
One of the key element that differentiate SARS from other existing corona viruses is that there are only three key proteins found in the extracted cell of this virus from different stages but the most important protein that is found in every coronavirus genes; hemagglutinin esterase can’t be found in SARS RNA. In between the already confirmed and studied genes of SARS, there are some ORFs or open reading frames that can’t be recognized. Two of these ORFs are found between spike and envelope genes where on the other hand, at least 5 of these ORFs are found between nucleocapsid and membrane genes. Existence of these unknown and unfamiliar ORFs is one of the reason that even after passing 18 years of the first outbreak of SARS, scientists and biologists are still figuring out the way to control and contain this virus if it ever breakouts again.