Are we ready for the next cycle of pandemic coming our way or shall we prepare ourselves for the one? Mentally, physically, emotionally and financially, it would be very tough for us to answer the above question and most of us do not want to.
Mankind was almost learning to get back on track amidst the ongoing pandemic, when it was again hammered down by the news of the emergence of a novel coronavirus strain. But, should we start panicking or be well informed about it? As it is said that half knowledge is highly dangerous, the latter would be a better choice.
This blog will be covering a few important things that we should get ourselves familiar with before creating any chaos or turmoil.
● In China (2003) the first SARS-CoV (severe acute respiratory syndrome coronavirus) outbreak took place. It spread in 29 countries and infected approximately 9000 people. They were associated with respiratory symptoms like bronchiolitis and pneumonia.
● In Saudi Arabia (2012) another virus called MERS–CoV (Middle East Respiratory Syndrome coronavirus), was isolated from a patient suffering from pneumonia.
● But, recently, a new coronavirus called SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) originated from Wuhan city of China in December 2019, causing life-threatening pneumonia in the people from Wuhan. This virus is the causative agent for the ongoing pandemic, Covid-19. As we can see around us, this virus not only affected human health, but it also caused disaster in human social, economic and many other aspects of life.
What is a coronavirus?
● Coronaviruses are common throughout the world. They are a large family of viruses. They cause respiratory illness in animals as well as in humans. There are several known coronaviruses that cause mild respiratory disease, such as the common cold. But, it is seen that the two coronaviruses have caused severe diseases within humans. These are Severe Acute Respiratory Syndrome (SARS) coronavirus and Middle East Respiratory Syndrome (MERS) coronavirus.
● The ongoing pandemic is also because of a coronavirus, but this is a new strain that has not been previously identified.
● Coronaviruses are said to be zoonotic, which means they are transmitted from animals to humans. It was found that MERS-CoV was transmitted from dromedary camels to humans and SARS-CoV was transmitted from civet cats to humans. There are several other known coronaviruses that are circulating in animals and have not yet been identified in humans.
● Common respiratory symptoms include cough, fever and shortness of breath. If not treated on time then infection can cause pneumonia, kidney failure and even death.
● Some standard recommendations are given to prevent the spread of infection. This includes washing hands frequently, using alcohol-based sanitizers, covering nose and mouth when sneezing and coughing, thoroughly cooking meat and eggs, avoiding close contact with anyone showing symptoms.
How SARS-CoV-2 causes infection in humans?
● The interaction between the viral spike protein present on the surface of SARS-CoV-2 and the human cell surface receptor ACE2 (angiotensin-converting enzyme 2), is the ability of the virus to infect human cells. The spike protein binds to the ACE2 receptor using three finger-like projections. These finger-like projections are called the receptor binding domains (RBDs). These binding domains help the virus to hook onto the cell surface.
● This interaction mediates the entry of the virus within the cell. The spike protein exposed on the surface of SARS-CoV-2 is the major antigenic
determinant and generates immune response within the host. These spikes are also the main targets for different antibiotics that are in development.
The interaction of the viral spike protein (in magenta) with the human cell surface receptor ACE2 (in blue). The antibodies (in black) disrupt the interaction between them and thus, not allowing the virus to infect the host
Picture source: https://www.sigmaaldrich.com/content/dam/sigma-aldrich/articles/biology/covid-19/covid-host-cell-graph.png
How different is the novel strain of the COVID-19 that is detected in the UK?
● The novel strain of the Sars-CoV-2 virus is known as VUI - 202012/01 (the first Variant Under Investigation in December 2020). It is also known as the lineage B.1.1.7.
● In December 2020 when samples were collected from patients living in parts of South England, this variant of Sars-CoV-2 was found in them frequently. The variant has undergone 23 mutations.
● In preliminary investigation, researchers and scientists have found that patients that are infected with this novel strain carry a heightened viral load, which means this strain is more concentrated in the upper respiratory tract. In other viral diseases, such a high concentration of virus in the upper respiratory tract is associated with severe symptoms.
● As per scientists, since November 2020 a similar type of variant has been detected in 90% of the samples from South Africa whose genome has been analyzed.
● Predominantly in the South and East of England, 1,108 cases have been identified with this variant as on 13th December 2020.
Picture source: https://timesofindia.indiatimes.com/img/79852738/Master.jpg
Why is this variant causing concern?
There are two most important things that are causing concern:
● The rapid replacement of other versions of virus due to mutations.
● The occurrence of the mutations affecting the most important part of the virus.
What do we know about the new mutations?
● The novel strain of SARS-CoV-2 has undergone several mutations in the spike protein and other genomic parts of the RNA virus. One of these mutations have been identified as “N501Y”, by COG- UK, in an area of the spike protein that binds to a key receptor, ACE 2, in the human cells. This is making the novel strain more infectious.
● It is observed that the mutation has altered amino acid sequence within the six most important residues in the receptor binding domain (RBD). This mutation will allow the spike protein to attach more easily with the human cells.
Is this novel strain of the virus deadly?
● As per the studies and investigations conducted by scientists and researchers, this novel strain of the virus is not deadly. However, the rate of transmission is 70% more as compared to the previous mutations.
● It is observed that this novel strain B.1.1.7, is spreading rapidly. In September 2020 the first case was detected and within 2 months quarter of cases in London were because of this novel strain. By mid- December, the number of cases rose to two-thirds.
● As quoted by Professor Willem van Schaik, Director of the Institute of Microbiology and Infection at the University of Birmingham, that “The new strain of the coronavirus is not more deadly but is contagious. This means that it is easier for this strain of the coronavirus to spread from one person to another”.
Where does the novel strain of Sars-CoV-2 virus came from?
The novel strain has several mutations and it might have evolved within a patient whose weak immune system was unable to combat the virus and thus, his body became suitable for the virus to mutate.
Will vaccines work against the novel strain of Sars-CoV-2 virus?
● Any vaccine when injected into the body trains the immune system to attack different parts of the pathogen. So, even though a part of the spike protein is mutated in the virus, the vaccines should still work.
● Scientists hope that the novel strain will not have any impact on any vaccines that are under development. This is because one significant mutation cannot change how a virus attacks humans. This scenario happens rarely.
● Viruses have the ability to beat the antibodies and vaccines and thus, escape immunity. But, according to the changes undergone by a virus, vaccines can be updated. The good news is to match up to changes undergone by Sars-CoV-2 virus, vaccines like Moderna and Pfizer can be easily altered.
● As per Shekhar Mande, Director General of the Council for Scientific and Industrial Research, the vaccines that are in development will work against the novel strain of Sars-CoV-2 virus.
Where else the lineage B.1.1.7. has been detected?
The novel strain has been found in other countries like Italy, Australia, Denmark, South Africa and Netherlands.
What measures have the Indian government taken against the novel strain?
● After concerns about the novel strain of Sars-CoV-2 virus, the Ministry of Civil Aviation has suspended flights from the UK till 11:59 pm, December 31. The suspension of flights is to start from 11.59 pm, December 22.
● As per Hardeep Singh Puri, Civil Aviation Minister, to maintain the utmost precaution, passengers that are arriving from the UK in all transit flights should undergo a mandatory RT-PCR test after their arrival at airports.
● Those passengers that have tested positive on their arrival should be sent for quarantine that is set up by UT/state governments. Those that have tested negative are advised to isolate themselves at home for 7 days and they will be medically monitored by the UTs/ states.
● The aviation authorities have specifically approved that cargo flights will be exempted from this nine day suspension.
● A new standard operating procedure has been issued, wherein, the government will be conducting genome sequencing of all Covid-19 patients who are arriving from the UK to determine whether the patient is infected with the novel strain of the virus or not.
To sum up…
Mutations are common in viruses. Any virus becomes invasive by making multiple copies of itself. The copies are always not the exact clones. There are many errors that creep into the process. However, few complex viruses have the ability of proof-reading mechanism that can correct the errors. But, in RNA- viruses, like Sars-CoV-2, this mechanism of proof-reading is not well developed and hence it leads to mutations.
Amidst the current scenario, what we can do is, take the utmost precautions by continuing wearing masks, maintaining hand hygiene, healthy diet and physical distancing.
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