“This disease can catastrophically affect almost everything in the body, and very quickly. The brutality of this virus knows no boundaries, it is striking and shocking. So says Dr. Hongbo Jia of the Institute of Biomedical Engineering and Technology of the Chinese Academy of Sciences.
Where to look for the "weak link"?
If we take into account the "shadow" statistics of the pandemic, according to which many cases bypass the official channels of information for one reason or another, we are faced with truly apocalyptic prospects.
Working on the article, the author studied the available sources and found that the number of patients had long ago exceeded several million, and the number of deaths exceeded no less than half a million people. At the same time, every minute the terrible score grows.
In this situation, the attending physicians cannot come to a single general picture of the disease and are still trying to understand what the virus is most dangerous for the human body. Some traditionally consider the lungs a "weak link", others pay attention to the cardiovascular system, others - to the gastrointestinal tract and organs of internal secretion, and some talk about the danger of viral damage to the brain.
What are the main features of the "crowned" virus known to scientists today?
And will doctors, overcoming professional contradictions, be able to leave the fierce controversy and develop a common clinical approach to the Covid-19 pandemic?
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Deadly attack
Virologists have already published more than a thousand articles in scientific journals on the nature of the coronavirus. However, the only indisputable conclusion here is one - there is no clear picture of the disease, and the virus behaves completely differently than others.
The main "gateway" for the penetration of SARS-CoV-2 into the body is the nasopharynx. The virus then searches for vulnerable tissues containing receptors that regulate blood pressure. With their help, he penetrates into the cell and begins self-reproduction, conquering more and more new territories.
At the beginning, the victim of a viral attack develops a high fever, a dry cough, a sore throat, a person loses his sense of smell and taste, he develops a headache and body aches.
If the victim's immunity is weak, SARS-CoV-2 attacks the lungs, after which the normal supply of oxygen to organs and tissues is cut off. Symptoms of pneumonia appear with continuous "barking" cough, shortness of breath and high fever. Many develop acute respiratory distress syndrome, and the oxygen content in the blood drops sharply. Such patients require artificial ventilation of the lungs, otherwise there is a high probability of death.
A number of doctors believe that in this condition, many seriously ill patients experience a catastrophic immune system response known as a "cytokine storm." It occurs when the content of cytokines - molecules that control the immune response - exceeds a critical level. Then immune cells begin to attack healthy cells, while blood vessels become permeable, blood pressure drops, blood clots form, and as a result, vital organs can fail.
But virologists are worried that attempts to weaken the cytokine response may backfire, and drugs that suppress the immune response will increase the spread of the virus.
Meanwhile, some scientists pay attention to completely different organs, which, according to them, contribute to the rapid deterioration of the condition in a number of patients. This is the heart and blood vessels.
Blow to the heart
One of the worst outbreaks of the pandemic occurred in Italy. Epidemiologists are still arguing about the cause, and virologists note the strange fact that many patients have traditional heart attack symptoms. At the same time, their hearts were so weak that they pumped blood three times less than the norm. But doctors at first could not find the blockage of blood vessels that feed the heart. Additional analysis immediately clarified the cause of this heart attack - Covid-19 was detected in patients.
Subsequent studies have failed to clarify how the virus attacks the cardiovascular system, although this happens quite often. By the way, almost half of the patients, even without signs of a heart attack, had arrhythmia.
Even stranger is the abnormally increased blood coagulation, leading to the formation of blood clots that block the arteries. In this case, there is a risk of developing pulmonary embolism, which is extremely dangerous for patients with Covid-19. Blood clots from arteries can also travel to the brain, causing a stroke.
The infection can also lead to narrowing of the blood vessels. Nutrition for the fingers and toes is impaired. This is the result of reduced blood flow, which can lead to swelling of the fingers and tissue death.
If Covid-19 affects blood vessels, this can also explain why diabetics and hypertensive patients with damaged blood vessels are at high risk of death. According to Russian doctors, they are deeply bewildered by the fact that there are relatively few patients in intensive care units with chronic diseases such as bronchial asthma. At the same time, there are many elderly patients with diabetes, obesity and hypertension.
Scientists cannot yet understand what exactly causes damage to the heart and blood vessels. Perhaps the virus directly attacks the heart and blood vessels, or perhaps the vessels are damaged due to lack of oxygen. There is also a paradoxical hypothesis that the immune cytokine storm also damages the heart and blood vessels.
War on the kidney front
Now all the attention in the world is riveted to the lack of artificial ventilation devices that help lungs that cannot cope with their task. But little is said about the shortage of dialysis machines vital to kidney failure. Meanwhile, the need for dialysis is due to the fact that the kidneys are also another target for the virus.
According to preliminary data from Chinese doctors, more than a quarter of patients in Wuhan suffered from kidney failure. In addition, patients with Covid-19 with acute renal failure died five times more often than those who did not have the disease.
It turns out that although the lungs are the main battlefield, the virus can also attack the kidneys. On autopsy images of the kidneys taken with an electron microscope, viral particles were found, indicating a direct viral attack. In addition, ventilators (ventilators) increase the risk of kidney damage, as do some experimental antiviral drugs. Hypercytokinemia can also reduce blood flow to the kidneys, causing fatal damage. In addition, diabetes mellitus also significantly increases the risk of acute renal failure.
Brain damage
Covid-19 was not believed to directly affect the brain and central nervous system. Now the situation has changed, and summary data allow us to speak about at least 10% of the total number of sick patients who have suffered brain damage, especially due to the stress of the body from being connected to a ventilator and taking tranquilizers.
Russian doctors note that they have met patients with meningitis, convulsive seizures, and also with a "sympathetic storm", as the brain version of the cytokine storm is called. At the same time, some patients with Covid-19 lose consciousness for a short time, they may have a stroke, they lose their sense of smell, and even the reflex of the brain stem, which feels oxygen starvation, is suppressed. This explains the dangerous paradox of insensitivity in patients with critically low blood oxygen levels.
There are other factors that can damage the brain. For example, a cytokine storm can cause cerebral edema, and increased blood clotting can cause a stroke.
The new path of the virus
Dr. Jianzhong Shi and his colleagues from the Harbin Veterinary Research Institute decided to test new ways of spreading SARS-CoV-2 and its effects on various human organs. To do this, they investigated the ways of transmission of infection to humans from domestic and wild animals. Thus, antibodies to SARS-CoV-2 were found in the blood of Wuhan cats - a sign that they had had Covid-19. Based on this, the US Centers for Disease Control and Prevention has recommended limiting contact with pets. This will allow you to protect yourself and your pets.
In cats, the virus was able to multiply in the upper respiratory tract, but did not cause serious consequences and death of animals. In felines, on the third and sixth days, viruses were found not only in the upper respiratory tract, but also in the lungs.
In addition, they were able to transmit the virus to each other. This was tested on three pairs of animals, in which one animal was instilled with a culture with viruses, and the other lived in a cage adjacent to the infected animal, separated by a four centimeter distance. A week later, the virus was found in a nearby cat, and three weeks later, antibodies to the virus were found in both animals. This suggests that cats are susceptible to SARS-CoV-2 and can transmit it to each other, and possibly to humans.