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About him in the program “Atheitis belongs to the” of “Žinių radijo” with the microbiologist of the Vilnius University Medical Faculty doc. Tomas Kačergis was discussed by his host Ignas Klėjus.
How have attitudes towards viruses changed since the start of the global COVID-19 pandemic?
According to T. Kačergis, something has not radically changed in the microbiology course he teaches and more attention is still being paid to bacteria.
“For example, we still associate seminars and laboratory work with bacterial infections, both for the nature of the work and for safety. Working with viruses, especially for students, would be really dangerous and expensive.”
Speaking of the lack of infrastructure to conduct virus research, he mentioned, in particular, the need for a certain level of biosafety laboratory.
“First of all, they must provide security for people who work with these viruses. This infrastructure, from a financial point of view, is expensive enough to make it difficult to develop. Economically viable countries, both Europe and the United States, can maintain those labs and having the capacity to carry out such studies. Therefore, it is too expensive for Lithuania. “
When asked why he chose to study viruses instead of bacteria, whose infections are much more common, the associate professor indicated that this was due to chance and certain circumstances.
“In fact, my supervisor was Professor Ambrozaitis (Head of the Infectious Diseases Clinic – Delfi) and he proposed a topic on resistance to antimicrobials, specifically bacteria, for my dissertation. I had to go to Denmark and do that work, but it turned out that the project of the researcher who was supposed to accept me was not approved and received no funding. So I had to choose an alternative and Ambrozaitis offered to go to the United States to Professor Stefan Gravenstein, who worked with the flu virus. That is where my journey as a virologist began ”, he opened.
According to the criteria of the definition of life, says Kačergis, a virus is not a form of life, because we understand life as a cellular form and a cell has certain structures, organoids that perform certain functions, and viruses are very simple in their structure.
“They consist solely of genetic material, nucleic acid and a protein coat. In fact, viruses do not have a cellular structure and therefore do not meet the criteria officially established by certain organizations. “
According to him, the virus could be recognized as a form of life unless nucleic acid is recognized as the basis of life.
When asked by a microbiologist how viruses work, he explained that they have a very simple structure consisting of just a nucleic acid and a protein sheath.
“The essential difference from all other microorganisms, such as bacteria, microscopic fungi, which also cause disease in humans, is that viruses are capable of entering the cell, that is, they are intracellular parasites. That is, it captures the entire biochemical apparatus of the cell, in this case the host, such as protein synthesis, and performs its own viral protein synthesis by capturing the cell’s ribosomes. These things stand out more when we compare viruses with other microorganisms. Viruses are actually genetic parasites that parasitize living cells and cannot survive without them. “
When asked what microbiologists fear most besides the COVID-19 virus right now, T. Kačergis mentioned the growing resistance to antimicrobial drugs, specifically bacteria and viruses.
“This is problem number one, because it is necessary to find out how to combat this phenomenon and what effective measures can be developed. Clearly, emerging infections are something else and are often associated with viruses. For example, the Zika virus, currently the COVID-19 virus, has also been waiting for a new flu pandemic for many years. Infections that occur primarily in animals and “jump” to humans are nearly impossible to predict and are feared. “
Currently six variants of coronavirus are known and, as the associate professor said, there are likely many coronaviruses in the same coronavirus family that are not even identified but are in animals and from which the infection can continue to spread directly to humans or through animals mediated by animals.
“This is very difficult to control and predict, so these emerging infections are a constant potential threat. Even those infections that have been forgotten, like fever, are particularly common in outbreaks and quite large. “
When asked to explain why so-called “old” infections sometimes recur, the associate professor replied that due to the fact that their bulbs were constantly burning and in nature.
“It is only a matter of time before and when they appear. Clearly, we cannot compare, say, the 21st century and the 17th century. In the age in which we live, we already have effective means of fighting these types of infections and how to manage them in effectively, something that could not be done, for example, in the seventeenth century, so there are some differences. Even though we live in the modern era and we have the right tools, those outbreaks happen constantly. If we don’t control them and somehow we predict them, this process will continue. “
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Humanity has been constantly exposed to coronaviruses.
T. Kačergis said that coronaviruses that were first identified using virological methods since 1966 actually existed before they were identified.
“Humanity constantly faced them, only at the moment of identification, when new methods emerged that allowed them to be identified. The first (coronavirus – Delphi) was identified in 1966, but it has been shown to cause mild upper respiratory tract infections and does not pose any major health risks. However, the effect it will have on the body is determined by the specificity of the virus for certain receptors in the human body.
Speaking of the constantly circulating coronaviruses that happen every year in the winter, fall, they just have different targets, different molecules in the epithelial cells that they stick to. While the new virus, including the first SARS virus, has a specific target, the second angiotensin converting enzyme. “
Therefore, according to the specialist, there is a problem here that said receptor is widespread in the body and is found in various cells. In particular, the associate professor said, it is found primarily in epithelial cells, in the respiratory tract, the gastrointestinal tract, and elsewhere.
“It is possible that all of these different disease symptoms associated with COVID-19 infection are caused by the ability of the virus to enter a variety of cells. When it enters the bloodstream, it can enter the various organs, their cells, through the bloodstream and cause organic pathologies. Therefore, it is the concentration of certain receptors on the surface of various cells that determines all matters related to the clinic. “
Coronavirus
When asked what he thought the further direction of the coronavirus mutation might be, the microbiologist did not want to draw immediate conclusions.
“It has only been six months since the pandemic began, so it is difficult to draw conclusions about in which direction it will or will not change at all. However, genetic studies are constantly being conducted with SARS-COV-2 viruses secreted by the human respiratory tract and show that these mutations are ongoing, but they are not so radical as to cause such changes when some characteristics of the virus change.
Most of the time, these are point mutations that are likely due to the fact that the viral enzyme required to replicate its genetic material simply makes certain mistakes during synthesis. This results in point mutations, but they are not cardinally important. “
Currently, T. Kačergis commented, three lines are distinguished according to the mutations that have occurred since the start of the pandemic.
“At the beginning of the pandemic, China was dominated by so-called option S, then it switched to option L and now Europe is dominated by option G. So there is a genetic variant that is more adapted to spread between humans. There have been changes in the region of the gene that codes for viral replication. It is feared that this change could render the virus insensitive to one of the drugs currently in use, remdesivir, which inhibits the replications of the coronavirus.
Therefore, the researcher said, it is this problem that is of most concern, but there are no other significant changes due to the change in the virus.
“As for the origin of the virus, perhaps there are three theories. One theory is that this virus originated by natural selection in animals and” jumped “into the human population. This is also shown by genetic studies, which clearly show that this virus It is derived from coronaviruses that circulate in bats.
The second theory is that this virus circulated in animals for some time and “jumped” to humans, and the unidentified ones could circulate in your body for some time before adapting to spread between humans. Those jumps between people can be episodic when they don’t even feel the symptoms, but are just carriers. “
He also cited a third theory, which he believes is perhaps more of a conspiracy theory, that the virus originated in a laboratory in Wuhan, China, where work was being done on the SARS-COV-1 virus.
“That theory states that the virus could have grown in human cells and over time, simply by forcing it and making it grow in human cells, making so-called passages or passes, it specifically adapted to the receptor for the enzyme angiotensin II that I mentioned.
However, this theory is officially disproved because the main protein involved in binding to human cells, specifically the second receptor for angiotensin converting enzyme, contains some insertion regions in that protein S that cannot be generated in vitro. This requires the intervention of the immune system ”, he concluded.
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