COVID-19: A candid talk with a budding Microbiologist Dr. Barnamoy Bhattacharjee

April 9: The history of viruses is as old as the history of life. The Latin term “virus” meaning “poison” shares its root with “visa” in Sanskrit, Avestan and ancient Greek and has been in use since the Middle Ages. In 1892, the University of Saint Petersburg alumnus Dmitry Ivanovsky discovered the Tobacco Mosaic Virus. Six years later, the Dutch microbiologist Martinus Beijerink coined the term “virus” to describe the submicroscopic infectious agent.These fascinating pathogens have dominated the imagination of researches over the decades since thanks to their remarkable life properties, their structures, their ability to undergo genetic mutations and their cytopathic effects on the host cell and also their enormous range of hosts making them the most abundant living entities on Earth.

In this ongoing COVID-19 pandemic, the tireless efforts of microbiologists and laboratory technicians has mostly gone unsung.They play a pivotal role in our global effort to tackle this crisis of epic proportions.

Dr. Barnamoy Bhattacharjee, a Post Graduate Trainee at the Department of Microbiology, Silchar Medical College & Hospital (SMCH) speaks on this issue with way2barak.  In this highly informative and pertinent conversation, Dr. Bhattacharjee unravels some lesser known facets of the dreaded entity COVID-19.

w2b: Could you tell our viewers the salient features of this pathogen?

Dr.B.B: SarsCov-2, the causative agent of CORONA VIRUS DISEASE 2019 is Betacorona virus. Its a spherical enveloped single stranded positive sense RNA virus of Coronaviridae family of size 120 to 160nm. It has spike like peplomers bearing antigens which give rise to its crown like appearance. It mostly spreads from Human to human via large droplets contaminating fomites. Though portal of entry  and route of transmission of this virus is mainly respiratory, there has been cases of its prolong fecal shedding in infants and children in the initial part of the pandemic from China. Extremes of ages and people with co-morbidities are prone to COVID19.

w2b: How does a virus change hosts from one species to another?

Dr.B.B: As far as viruses like SarsCov-2 are concerned , 2 probable theories have been put forward. The virus either remained in circulation harmlessly in humans but due to natural selection Antigenic shift occurs resulting in Pandemic. A second theory that has been postulated after gene sequencing and phylogenetic analysis that SarsCov2 originally bearing closest match with a Bat Sars corona virus jumped to human species with an inbetween stint in animal due to persistent antigenic drift that is slow and steady point genetic mutations. Infact species jumping has been one of the survival strategies of viruses in Interepidemic period.

w2b: How do you clinically extract the evidence in favour of the virus?

Dr.B.B: Clinical confirmation of SarsCov-2 involves demonstration of E( envelope) gene , which is Group or Genus specific, in Nasopharyngeal swab or aspirates or oropharyngeal swabs in case of symptomatic patients with Upper Respiratory Tract Infection or Broncho alveolar Lavage or sputum on cases with Lower Respiratory Tract Infection by Real time RT-PCR which is the screening test. Cases found positive in screening test has to be confirmed for Rdrp gene and ORF 1b gene which are species specific and has high specificity unlike sensitive screening test. Test done is again Real time RT PCR. Unless the result of a positive confirmatory test is verified and validated by National Institute of Virology, Pune, the testing Laboratory is not allowed to disclose the positive result in public.

w2b: How are the confirmed positive cases followed up for remission ?

Dr.B.B: The follow up samples from Lab confirmed positive cases, be it Nasopharyngeal or throat swab or blood sample, should be tested for remission at an interval of 2-4 days after the patient becomes clinically asymptomatic. Two consecutive negative tests at least 24 hrs apart demonstrates viral clearance and the patient can be declared free of SarsCov-2 infection.

w2b: How much has been confirmed about the conditions in which this virus gets activated ? Is there any role of seasonal variation?

Dr.B.B: Some theories are doing round that Sars Cov2 gets inactivated at temperature more than 26 degree, but till now this has not been proved scientifically . Seasonal variation may lead to pressure of natural selection, mutations and selection of alternative intermediate hosts for survival.

w2b: Is there any relationship between specific blood groups and COVID-19 infection?

Dr.B.B: To be precise, some studies from China have come up with view that people with Blood group A are infected more with Sarscov2 and those with Blood group O are least prone . But this being a study in very initial part of Covid 19 spectrum and that too with small number of cases, this hypothesis cannot be validated.

w2b: As a budding Microbiologist, how would you describe this ongoing pandemic? How long can we think of a lockdown taking into the account the virulence of the pathogen?

Dr.B.B: Medical Microbiology is probably the Lynchpin of the entire task force of  managing the herculean challenge of ongoing pandemic as its the agency concerned with diagnosing these huge number of cases by conducting the highly sophisticated but time consuming real time RT-PCR. But I believe Lockdown and Contact tracing of lab confirmed positive cases can be a key strategy in preventing this Pandemic (which already by now has seen change in the form of SarsCov2 from L form to S form) from creating further havoc . Given that there is no more influx of supposedly exposed cases, Lockdown for one month should suffice for the already exposed asymptomatic persons in Incubation to develop symptoms and lead the Govt and health agencies to trace the already Quarantined contacts, provided the lockdown norms are stringently followed and measures like Proper hand hygiene and social distancing are practised to avoid the rapid spread of this virus .

w2b: Take on rising cases and appeal to public….

 Dr.B.B: With the rapid increase in number of cases (globally heading to 14 lakhs) and death toll (approx 76000) globally and number of COVID19 cases in India crossing 4700 with around 150 mortalities and Assam at 28, its high time the citizens act responsibly for containment of the disease and so I urge upon the Indians with history of foreign travel or travel to any territory affected by this pandemic to come forward and get themselves tested and stay in quarantine and help the Indian Govt. to combat COVID19.

(way2barak expresses its thanks to Dr. Himabrata Das & Dr. Barnamoy Bhattacharjee for this interview)