With more than 147,800 infected and nearly 5,500 dead as of March 14, covid-19 has spread to more than 110 countries.
Although there are still many doubts about this new virus that first appeared in the central Hubei province of China, towards the end of 2019, contagion is estimated to occur when we aspire little drops expelled through the cough or sneeze of an infected person.
Also when we come in contact with a contaminated surface by the virus.
We also know its symptoms: tiredness, fever and dry cough They are the main ones, but also some patients may have pain, nasal congestion, sore throat and diarrhea, according to the information page of the World Health Organization.
But what exactly does the coronavirus do to our body? How does it infect you? And how does our body look after overcoming the disease?
“The coronavirus is mainly a respiratory virus“William Schaffner, professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center in the United States, explains to BBC Mundo.
For this reason, it begins infecting the throat.
When the virus enters our body —either through the eyes, the mouth, or the nose— “it attaches itself to the mucous cells at the bottom of the nose and throat,” says the expert.
Thanks to its lance-shaped proteins that protrude from the surface, the coronavirus can penetrate the membrane of these cells.
“And once inside the cell, like the other viruses, it begins to give it the order to produce more viruses.”
This is the way the virus has to replicate, since being a microscopic acellular infectious agent, it can only multiply within the cells of other organisms.
Once the copies are ready, they leave the cell where they originated, destroy it, and begin to infect other cells.
Each virus can create between 10,000 and 100,000 replicas.
“When this occurs, the body realizes that the virus is there and produces an inflammatory response to try to fight it,” explains Schaffner.
“So that’s why we started to feel a little bit of sore throat and we may feel a stuffy nose. “
“The virus then goes to the bronchial ducts (the airways that go to the lungs) and there it produces an inflammation in the mucosa of these ducts ”.
“This causes irritation and therefore we begin to coughSchaffner notes.
As this occurs, “the inflammatory response increases because the body is fighting the virus, and as a consequence, the fever”
At this point is when we start to feel bad and lose our appetite.
According to an analysis by the World Health Organization based on the study of 56,000 patients, the 80% of those infected will develop mild symptoms (fever, cough, and in some cases pneumonia), 14% severe symptoms (shortness of breath and shortness of breath) and 6% will suffer a serious illness (lung failure, septic shock, organ failure and risk of death).
The situation may worsen if the virus “leaves the bronchial duct and reaches the lungs, where it causes inflammation (pneumonia) ”.
“If a sufficient portion of lung tissue is affected, it will be more difficult for the patient to breathe, because they cannot breathe out the ‘bad air’ and inhale the ‘good’.”
When the body cannot receive enough oxygen, the patient must be hospitalized and may need to be connected to a respirator.
The problem is not just the infection, but the how our body responds To fight it, he explains to BBC Mundo Kalpana Sabapathy, a clinical doctor and epidemiologist on the global health team at the School of Hygiene and Tropical Medicine in London, UK.
“To prevent infection from hijacking our cells, our bodies produce chemicals that are quite aggressive.”
In the case of pneumonia, “it creates congestion in the small air sacs at the base of our lungs (alveoli).”
These small structures are the ones that normally fill with air, and through their walls the gas exchange takes place by which oxygen reaches the blood, and from there to the rest of the body.
“But if these bags are full of infection, combined with our body’s response to that infection, they have less capacity for air,” says Sabapathy.
“And if the body doesn’t get enough oxygen this results in respiratory failure, and the heart, not getting enough oxygen through the bloodstream, can’t function.”
Schaffner compares the inflammatory response with a warlike conflict.
Imagine it is a war. There are two armies that fight each other, but sometimes the bombs hurt civilians. Or they can fall on the hospital, or the museum, but not on the enemy, “he says.
In other words, the response can be so powerful that it ends up damaging the tissue where the virus is found.
“Call collateral damage. This is what can happen when the inflammatory response is so vigorous that it adds to the problem of pneumonia (…) ”.
This means that the infection does not need to move to another part of the body for an infected person to be in a critical condition.
So … can the coronavirus also spread to another part of the body?
From nose to rectum
As explained to the New York Times Amy Compton-Phillips, clinical director of the Providence Health System, in the United States, the infection can spread from the nose to the rectum.
A study published in March in the prestigious magazine The Lancet not conclusive, but also suggests that covid-19 “is not only capable of causing pneumonia, it could also cause damage to other organs like the heart, liver and kidneys, as well as in body systems such as the blood or the immune system. “
Based on studies that have been done on SARS (severe acute respiratory syndrome), “cousin” of covid-19, “we think it can go to other parts of the body,” says Schaffner.
This may partly explain why some infected patients have suffered diarrhea and abdominal pain, problems that are not directly linked to a respiratory infection.
These diseases, says Schaffner, referring to SARS and MERS (Middle East respiratory syndrome coronavirus) “look very similar in their most severe stages.”
But to reach this conclusion, it will be necessary to “know the results of the autopsies, and that information is only beginning to be revealed,” he says.
As for long-term damage, both in the lungs and in other organs, the specialist says that the vast majority make a full recovery.
Although also “there are some reports of patients who, as a consequence of inflammation, may have some scarring in the lungs and a reduced lung function.”
“It will take time to determine this more precisely, and attention is now focused on acute cases of the disease.”
“We have not had time to think about the long term yet,” concludes the expert.
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