Viruses, these small and powerful creatures that are difficult to tell whether they belong to living things or not, are not so almighty, because they cannot survive without penetrating the living cell they use to reproduce, and then kill it.
Very little number of organs are needed for a human to live, and therefore quite a number of body parts in a vital sense is completely unnecessary. Viruses have brought this rationality to perfection: the virus is a simple biological device purified from most unnecessary parts. By definition of a living being (you know already: homeostasis, organization, metabolism, growth, adaptation, reproduction) the virus can barely be counted into the living world. It is built to maximize its functionality and minimize energy consumption and the need for environmental survival conditions.
The virus is actually a thin lipid membrane to which several lumps of connective protein are attached from the outside, into which only the most basic genetic material is wrapped. Coronavirus (SARS-CoV-2) as a genetic material contains single-chain ribonucleic acid, RNA and that’s all it needs for life. The virus lacks practically all the other parts that exist in other living cells: it has no mitochondria that produce energy, no cell wall or cytoplasm, no nucleoplasma, no vacuoles, lysosomes, ribolas, endoplasmic reticulum or Golgi’s apparatus… This in turn means that it does not have the parts of its own necessary for life and reproduction.
How then their lives and reproduces? Simple, and brilliant: for this, the virus uses another living cell it enters and which is insidious like a Cuckoo bird who has no nest but a egg planted on another bird to sit on it, hatch it and feed it to a bird that is not hers, and which will take all the food and living space intended for other birds, to plant its genetic material in our cells. Then the cells, not realizing that they’re executing messenger information from someone else’s genetic record – the rest of the reproduction done instead of the virus.
Coronavirus is most common in the cells of our respiratory system, those that coat the respiratory organs (respiratory epithelium). The epithelium is connected to the surface by its spike proteins , which are “pinned” to the epithelium in specific places, so-called “spikeproteins”. receptors for the virus. In the case of SARS-CoV-2 viruses, these are receptors that in a healthy organism are normally used to bind the angiotensin-converting enzyme in charge of regulating blood pressure, ace2-receptor.
If we skip many times the chewed topic on ways of transmission (in short: wash your hands!) and assume that the virus has reached the mucous membrane — after adhesion (adsorption) to the respiratory epithelium, the virus through the membrane of the epithelial cell protised (“syringe”) of its RNA in the “gut” of our cell, i.e. the membrane of the epithelial cell. Insert your genetic material, the information intended for our cell apparatus to “assemble” new viruses and form thousands of identical copies of that single virus that made the “landing” on the station.
And the epithelial cell, not knowing that it has “fostered” foreign genetic material, accepts viral RNA as its own and follows its simple instructions: “copy ⇒ multiply ⇒ compositions”. All of its resources directs our infected cell to complete exhaustion towards this imposed task, until it is fully fulfilled by thousands of copies of the virus and then receives the final genetic “command” – to destroy itself. And the cell really disintegrates, releasing new, newly composed viruses that then attack adjacent healthy cells and repeat the cycle: adsorption at the receptor – inserting RNA into the cell – forcing the cell to hyperproduct new viruses – cell breakdown – spread of the virus to new victim cells.
The number of infected cells – you assume yourself – is growing exponentially (a favored mathematical term in epidemiology and infectious disease), so after ten days it is infected with millions of cells in the respiratory system, and by our lungs they slither, beaches and numerous billions of viruses. But despite this exponential invasion of our respiratory epithelium, the virus has not yet caused too much damage: the person to whom it has happened will only have symptoms resembling a common cold, down to moderately strong flu. Because our healthy and normal “pinched” immune system protects us.
So what makes COVID-19 so dangerous, and for some people, a deadly disease? Now, here’s the point: the biggest enemy in the COVID-19 infection is not the SARS-CoV-2 virus, but just our defender and savior, our own immune system.
Sometime in the middle of the second week since the onset of the disease (about 10 days) in our body can happen spectacular but tragic remake of the movie “2Fast & 2Furious”: our immune system can slip away from self-control and react too quickly and too fiercely with its otherwise defensive arsenal.
Two types of immune cells are particularly heavily armed to fight aggressors: neutrophils, which by releasing proteolytic enzymes can destroy any virus, bacterium or cell, and T-cell-class lymphocytes, affectionately known as killer-cells, because of their ability to force infected cells to – suicide.
Our immune cells, which rush into viruses that have flooded their lungs, run into billions of multiplied viruses when they arrive at the scene. The fighting wave of incoming immune cells interacts with each other by releasing and receiving small signaling proteins called cytokines, which regulate the strength and direction of the immune response. But viruses have a simple tactic: “Look, new cells have arrived! Let’s infect them too!”, so viruses infect some of these immune cells.
Infected immune cells immediately secrete additional cytokines, which in turn attract new immune cells with even more cytokines, which spins all over again in an exponential spiral… And you got it, didn’t you? – in a record short time, the entire organism is inundated with billions of fiercely killer immune cells, whose explosions destroy everything around them, uncontrollably squasting powerful defensive resources – both viruses and the surrounding cells of their own organism.
In short – a cytokine storm occurs.
And in this storm, cytokines vigorously stimulate both classes of immune fighting cells, so neutrophils uncontrollably and explosively release large amounts of aggressive enzymes capable of killing everyone in front of them (including their own cells), and killer T-lymphocytes in a state of confusion begin and completely healthy cells order suicide. The vicious circle is closed.
The more immunological stations are affected, the more damage is caused at the surrounding stations, which means that they are destroyed and the lung stations that were still healthy by that time, and somehow succeeded to maintain the breathing function. Such damaged lungs are literal and exposed, without the possibility of adequate defense of new infections, so it is very common that the corrosive lung damage is superponed (above) and severe bacterial inflammation of the lungs (the so-called secondary bacterial pneumonium, which is caused by the bladder resistant to most standard antibiotics).
The organism, exhausted with over two weeks of fierce immune battle and with depleted defensive resources, no longer has the strength to defend, so the lungs – covered with viruses, bacteria and suffocated by thick sticky mucus – fail both functionally and anatomically (acute respiratory failure, ARDS): the patient ends up on a respirator.
And since the immune system is “on the knees”, the infection from the lungs practically expands further, so the agents enter the bloodstream, with the spread of infection to all organic systems, i.e. sepsis – the general inflammatory response of the whole organism (SIRS, Systemic Inflammatory Response Syndrome). Depleted organs one after the other lose their function and gradually fail, which is called multiple organ failure (MOF, Multiple Organ Failure).
Sudden failure of liver function results in the disruption of the formation of coagulation factors, the result of uncontrolled blood clotting in the blood vessels throughout the body, which is a common side effect of sepsis: disseminated intravascular coagulation (DIK), which depletes the body’s reserves of clotting factors, resulting in mass bleeding into the lungs, intestines, brain, adrenal gland…
The sequence of events described in connection with the cytokine storm is rapid: it is measured in hours. The speed and timeliness of the chronological order of therapeutic measures is crucial. However, even with the most ideally organized and complex therapeutic measures, the survival of patients is only 40-60%, even in those who did not have significant chronic diseases prior to COVID-19 disease.
Even if the patient survives this immune cataclysm of self-destruction, the lungs that have been exposed to a cytokine storm can suffer permanent and irreversible damage. Moreover, even in patients who did not “fly” into a cytokine storm, but their immune system managed to “stay on their feet” and overcome COVID-19 without the appearance of severe symptoms, the consequences of this struggle within the lung tissue between immune cells, cytokines and viruses can cause damage to the surrounding healthy lung cells, damage to lung function that can remain noticeable in chronic form, throughout the rest of life.
Is there any help other than putting on a respirator and implementing general and supportive medical measures? Good question. Ideally, it would be to have a specific SARS-CoV-2 vaccine, or a reliably effective antiviral medicine. But for now, we don’t have any, although the announcements are promising. Several vaccines are currently in different stages of clinical testing, and the drugs are mostly in the experimental or initial clinical stages of efficacy trials vs COVID-19.
Stay tuned. And stay at home.
UPDATE: Some people report this to Facebook as abusive. This is writed by Croatian doctor and is translated to English. Many sites write about Cytokine Storm: Check it on Google – https://www.google.com/search?client=firefox-b-d&q=Cytokine+Storm+covid-19 or read about Cytokine Storm on BBC: Cytokine storms: When the body attacks itself!
Then if you still think it’s abusive we will remove the article! Thanks