Let us know some facts about Coronavirus
- Post By : Dr. Girish B. Mahajan, Ph.D.
- Source: Microbioz India
- Date: 27 Apr,2020
It was post-dinner time on Saturday 4th April 2020; the 12th evening of lock-down in India. Mr.Madhav was sitting in front of his laptop eagerly waiting for the bell of 10 pm on Web meeting. He and his close friends Kiran, Avinash, Santosh, Suhas, Mahesh, Rajan, Seema, Kavya, Vidya, Geetanjali and Namrata from different places in Maharashtra state used to meet daily on Web meeting to have a free discussion and to update each other. On that day all of them were very eager to be on this web-meeting, for a special reason; as Dr.Vasudev (DV), the well-known Virologist and classmate of Madhav had promised to be on the group on the invitation.
And it was 10 pm…. all 12 members started chirping on Web. Within a minute Dr.Vasudev joined the conversation. After his formal introduction by Madhav, everyone was just eager to ask queries to Dr.Vasudev.
Madhav: Now it’s time to have an informal discussion with DV, for our Coronavirus queries.
Avinash: DV, thanks for coming live on the group. Can you please tell me about this Coronavirus which has become globally viral, especially little about its history, size, and its unique name?
DV: Yes definitely. I am glad your group thought of such an idea to get exact information about this virus and the disease. A virus is a very tiny microbe, which is active only when it gets contact with its specific host or tissues in our or animal body. When I say tiny, this new Coronavirus that is SARS-CoV-2 is of 80-140 nanometre in diameter. OK, let me explain how small it is. Your normal ball pen tip is of 1mm diameter. On its tip about 1.7crore to 3.9 crores, such viruses can comfortably reside.
Kavya: What 1.7 to 3.9 crores!!!
DV: Yes, based on its size. Human coronaviruses were first reported in 1965, by Tyrrell D.A., Bynoe M.L. Later in 1975 it was put into a new Genus. One interesting thing, the virus has the crown-like appearance of the surface projections. It gives the virus an appearance like a crown. Hence the name was “Corona”. In Latin “Corona” means crown.
Namrata: Thank you. It seems there are many more interesting facts about this virus. When I look at its pictures, the shape appears very attractive and well-structured with lots of nails on its surface. Can you tell us about its structure?
DV: Namrata, your observations are very true. The new SARS-CoV-2 virus is spherical and has outgrowths called spikes protruding from their surface, you described them as nails. These spikes are made up of a special sugar & protein combination, called glycoproteins. These spikes latch onto human cells when the virus attacks humans. The sphere is made up of Protein and some lipids. Inside the sphere is its RNA (Ribose Nucleic Acid), the mastermind of the virus. The pictures which we see often are schematic diagrams of the electron microscopy views under 1,00,000 time’s magnification. By the way, these spikes play an important role while attacking human cells, and also they are very important for vaccine development.
Santosh: Very good information DV. But tell me please, how many such Human coronavirus can infect humans?
DV: Good question. The seven coronaviruses that can infect humans are: 229E (alpha coronavirus), NL63 (alpha coronavirus), OC43 (beta coronavirus), HKU1 (beta coronavirus), MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome, or MERS), SARS-CoV (the beta coronavirus that causes the severe acute respiratory syndrome, or SARS), SARS-CoV-2 (the novel coronavirus that causes coronavirus disease 2019, or COVID-19)
Sometimes coronaviruses that infect animals may evolve and make people sick and become a new human coronavirus. Three recent examples of such evolved viruses are 2019-nCoV, SARS-CoV, and MERS-CoV.
Geetanjali: Oh!! I see. I thought it is only one virus that was transmitted from bat to human. This is a wonderful insight you gave. DV is it true; this new virus has come from bats?
DV: OK, let me explain this. Many health experts believe that the new strain of coronavirus likely originated in bats or pangolins, or marine food. Pangolins are ant-eater animal and endangered species. The first transmission to humans was in Wuhan, China. Since then, the virus has mostly spread through person-to-person contact. To share more, Coronaviruses are common in certain species of animals, such as cattle and camels. However, it remains unclear exactly how the virus first spread to humans.
Suhas: But I wonder does this virus cause any disease in bats and those other animals?
DV: Bats have been reported to be reservoirs of many types of viruses of the group corona, Nipah, Marburg & the Hendra and rhinoviruses, lyssaviruses, and adenoviruses. Despite the reservoir of such deadly viruses, bats can dampen inflammation caused by viruses. Bats have a physiological mechanism that helps them combat inflammation from flying. This mechanism is thought to also protect the bat against the diseases caused by the Corona group of viruses.
Kiran: Doctor, is it true that these coronaviruses are usually transmitted by an intermediate animal from bats to a human?
DV: Yes correct. Civet cats were intermediates during the SARS outbreak, dromedary camels in case of MERS, horses passed on the Hendra virus, and pangolins are thought to probably have transmitted COVID-19 viruses to humans via a wet market in Wuhan.
Vidya: I have one innocent question DV. What is so scary about this virus as there are more deadly diseases around us like TB, hepatitis, typhoid, cancer, etc?
DV: SARS-CoV2 is a new virus to which no one has immunity. Its average mortality is about 3.4%, which is lesser than other corona viral diseases like SARS and MERS. However, it is highly contagious and spreads through contact and /or even air as per recent studies. Persons who are in contact with COVID-19 patients/asymptomatic carriers/corona carrying animals are more prone to get infections.
Seema: Can I catch COVID-19 from my pet? I have a beautiful cat at my home.
DV: I have not heard any such case in India till date. However WHO has on records, the instances of animals and pets of COVID-19 patients being infected with the disease. World Health Organisation (WHO) further documents that Based on current evidence, human to human transmission remains the main driver. It is still too early to say whether cats/ or any other pet could be the intermediate host in the transmission of the COVID-19.
Seema: Thank you Doc. It is now known through social media spread knowledge that at present there is no approved drug/vaccine or any ensured specific remedial measures for the treatment of COVID-19. But please tell us the future possible ways to curtail COVID-19.
DV: Yes Seema, that is the most frequently asked question. There are few antimicrobials with potential activity against SARS-CoV-2; such as Hydroxychloroquine, Chloroquine, Lopinavir, Ritonavir, Remdesivir, and Favipiravir. Some compounds are adjunctive or for supportive care such as Azithromycin, Immunomodulating agents, COVID-19 convalescent plasma, Anticoagulation, and interleukins like Tocilizumab, & Sarilumab. Apart from this strong research is ongoing rapidly in several countries in developing a successful vaccine. Plasma therapy and stem cell work are also being followed extensively.
Mahesh: It is a very positive feeling DV to listen that so many remedial things are on their way. Man is geared himself to shut off this tiny demon, the Coronavirus. One curiosity floats in my mind from the last few days.
DV: Yes Mahesh please feel free, say it!!
Mahesh: Not all people who get infected by this new Coronavirus die, only very few die. Why?
DV: That’s the good point you brought here. See first of all our body’s resistance power, which is called immunity is very important.
Immunity power of our body is based on age, our diet, the amount of exercise we do, if one has chronic diseases, is he or she on medication of some drug, etc. So based on our immunity power, not everyone who comes across the infective agent will get infected. Again dose or number of infective particles to which one exposed is also important. Now next stage, even if one gets infected with virus particles and initially some mild symptoms have shown but our immunity power overrules the attack, and within a couple of days, patients recover. If patients show stronger symptoms then they are treated symptomatically and with some of the antimicrobial or support therapy mentioned above, which is purely based on the clinician’s decision. This therapy gives some support to immunity and the patient recovers soon. Very few roughly 4% of the infected one go to the very sad stage. Since it is a new pathogen its a new experience for us. I hope I am clear.
Mahesh: Wonderful DV!! Sir, I have a very basic question. What is the logic behind a 1-meter distance between two persons when you are outside the house?
DV: Social distancing is an effective protective measure against the new coronavirus, says the World Health Organization. Maintain at least 1 meter (3 feet) distance between yourself and anyone who is coughing or sneezing. When someone coughs or sneezes they spray small liquid droplets from their nose or mouth which may contain the virus. If you are too close, you can breathe in the droplets, including the COVID-19 virus if the person coughing has the disease. Also, 1 meter provides personal operational freedom to a person.
Kavya: Oh how perfect scientific thought behind this 1 meter. OK DV let me bother you with one more information spread across. What is the correlation between the BCG vaccine and new coronavirus infections?
DV: The Bacillus Calmette-Guerin (BCG) vaccine, administered to millions of Indian children soon after birth to protect against tuberculosis, could be a “game-changer” in the fight against the deadly coronavirus, say US scientists. The severity of coronavirus impact may be linked to national policies on BCG childhood vaccination, the yet to be published study from the New York Institute of Technology (NYIT) states while citing the examples of Italy and the US. It was found that countries without universal policies of BCG vaccination, such as Italy, the Netherlands, and the United States, have been more severely affected compared to countries with universal and long-standing BCG policies. It needs to be yet established technically.
Rajan: Ok Doctor, I heard of 14 days quarantine period. Why 14 days, why not 10 days or 21 days or 30 days?
DV: (With a smile), yes I will explain mantra of 14 days. The “incubation period” of the virus, which means the time between getting infected with the virus and beginning to have symptoms of the disease. Most estimates of the incubation period for COVID-19 range from 1-14 days, most commonly around five days. It means if we suspect anyone is infected with COVID-19 virus and if he/she is quarantined for 14 days and if no symptoms then in most of the cases it means he/she is corona negative. These estimates will be updated as more data become available.
Rajan: Every number mentioned in these Corona pandemics has some science behind it.
Madhav: I think it’s time to say bye to Dr.Vasudev, as tomorrow early morning he has to rush to the hospital for his patients. We are almost close to the next day. Thank you very much, DV for coming on our web meeting and resolving queries about COVID-19.
DV: It’s my pleasure. So all of you stay safe and stay in home to help us to break the chain of Coronavirus and come out of this global problem.