Corona Virus Pandemic, All You Need to Know and Do From the Physiologist Point of View
This article will contain a little detailed medical information and terminologies that I will do well to explain to them to favor all my readers. This article is not written to scare or put fear among persons diagnosed with the virus, but it rather focuses on educating and providing you with all the necessary information needed to guide and protect you from being affected by the virus. Although this piece will have much-solicited information that may be solicited from other sources, for the sake of ease of reading and better understanding by the general public, there will be no in-text citation but rather a general list of possible reference materials.
Etiology OF COVID-19(Origin of the coronavirus).
The Novel coronavirus (NCOV) has been identified as the cause of the coronavirus disease 2019 (COVID-19). The NCOV or SARS-Cov-2 belongs to a group of viruses with a bilipid coat that gives them some form of protection. Ordinarily (under normal circumstances), viruses are pieces of proteins containing some sort of genetic materials that give false information to host cells to produce wrong proteins in the body. Viruses themselves are not alive (i.e., they are not alive as bacterial and protozoa). It means they do not feed or reproduce when they are not in any living organism. Unique about is that they have lipid coat that surrounds this protein piece I have described above and thus, provides them some good protection. While some coronaviruses are already well known such as the SARS, MERS among others, the SARS-CoV-2 is very new with little or no information about exactly where it came from. Almost all information presently out there is mere speculation.
PATHOGENESIS (How SARS-CoV-2 causes COVID-19).
The majority of news outlets and people have usually confused the name of the virus and disease it causes. The virus is called Novel Coronavirus (NCOV) or severe Acute Respiratory syndrome coronavirus disease identified in 2019 (COVID-19). As mentioned above, NCOV is a respiratory system virus which means it only affects the respiratory system. The respiratory system is a part of our body that helps us to breathe. This part comprises the nose, trachea (generalized for tube between nose and lungs), and lungs. As we know, breathing simply involves exchanging gases between our body and the environment, this means that virus must be carried in air or get some access to these places mentioned. However, virologists at the WHO have arguably (I don’t believe wholly) said the NCOV does not freely float in the air, but rather transported with water droplets from talking, sneezing, or coughing by infected individuals and hence described as aerosolizing (little droplet of water in the air). However, a recent Japanese experiment has revealed that, while relatively larger droplets of saliva from a cough or loud talking or sneezing may quickly drop-off the ground, the very light ones remain floating for quite a long time up to about 20 minutes in a poorly ventilated environment, and this gives a crude (not too clear) idea that, NCOV is nearly airborne. When the virus comes into contact with the host through their eyes, nose, or mouth, it is absorbed by the body. This becomes easy because our body cells have similar lipid coats so the virus lipid coat easily dissolves in our cell membrane (the layer that surrounds the cells). The virus does not have motility (does not move), it is our body that absorb it. When it is absorbed into the body, there may be an immediate response to it by individuals with a strong immune system and eliminate it quickly or later, and such individuals may only show systems of upper respiratory disorders (mild-cold or flu “catarrh and running nose”). Those with the weaker immune system may not respond until after some time.
PATHOPHYSIOLOGY (How the body responds to COVID-19).
The final target of the NCOV is a type of cells in the lungs known as pneumocyte type II (lung cell type 2) which is found in the lungs. The function of this cell is to produce surfactants (lubricant in alveoli from collapsing) alveoli are balloon-like structures in our lungs that open and close to pump air, without surfactant, the alveoli fail to open when it closes. Unfortunately this is the cell NCOV targets. I very healthy individuals who have a very strong immune system as aforementioned, the NCOV may not reach this cell which is very deep in the chest through the blood or other routes but would be eliminated quickly or silenced without having the disease COVID-19. In that case, the body develops very strong resistance for the virus and does not allow it to cause any harm. However, in people with a weak immune system or any underlying condition, the virus is carried in the blood until it finds its target pneumocyte type II. This cell has an ACE receptor (a receptor is like a lock to a door, once you have the right key, you can open it and enter the room). This ACE receptor is where the NCOV binds, once it endocytosed (the cell swallows the virus) in the pneumocyte type II. In the pneumocyte type II, the genetic material I mentioned earlier on, is incorporated into the normal human genes in the cells and the genes make more copies, the virus genes multiply, but because these new genes are not normal in the lungs, the pneumocyte type II dies.
As the pneumocyte type II begins to die, the body’s immune system is alerted. So it sends some special inflammatory cells which include interleukin 1, 6(ILT1, 6), and tumor necrosis factor (TNF) to destroy the dying or dead pneumocyte type II which is inside the alveoli, this process is called inflammation. As these inflammatory cytokines destroy the dead cells, there is a production of pus (an example of fluid) because the body breaks down the bad cell and the inflammatory cytokines together in a process called liquefactive necrosis. This fluid begins to fill the alveoli, and as more and more pneumocyte type II cells are attacked by the virus, more inflammation occurs and more pus is produce filling the alveoli. The filing of the lungs with pus is what is called PNEUMONIA. In this pneumonia depending on its severity the individual is unable to breathe making the person hypoxic (low oxygen in the body). During this time the person will have an unproductive cough (dry cough), headache, and high body temperature, and so on. Due to this the body tries to add additional force to get oxygen so the individual breathes faster and stronger (panting) for air (this is called Acute Respiratory Distress Syndrome-ARDS). After some time if there is no support, the muscles in the chest which help in respiration become fatigued because there is no oxygen. Then the brain starts dying and the other organs as well, then the individual dies.
In a lucky situation where the patient is placed on a ventilator (the machine that pumps oxygen into the lungs), the body gradually removes the dead cells and the patient starts to recover. Some patients die even when placed on a ventilator because, they may have lost too much of their alveoli and are not able to recover.
DIAGNOSIS (How to tell if someone has the virus)
In asymptomatic patients (people with the virus but shows no signs and symptoms), the only way is to do a laboratory test called Polymerase Chain Reaction (PCR), a complicated laboratory test that increases collected genes and can tell if the virus gene is present in such gene. This is an expensive test done in some special labs. In symptomatic patients (patients that show signs and symptoms) the signs and symptoms can give a hint but only the laboratory test can confirm.
The virus is very new and virologists have little information about it, thus far there is no known direct treatment. Clinicians only manage the direct treatment. Clinicians only manage the symptoms and place patients on ventilators. In about 80% of cases patients recover through this management. All medicines you have heard in the news are still under clinical trials.
Most viruses are prevented by vaccination, however, SARS-CoV-2 has no vaccine yet. Prevention is therefore, an individual’s effort to try as much as possible to observe those advertised by WHO. Observing social distancing, washing hands under running water with soap, staying at home, and also avoiding touching eyes, nose, and mouth.
- Barrett KE, Barman SM, Boitano S & Brooks HL. (2012). Gannon’s Review of Medical Physiology, Twenty-fourth ed. New York: McGraw-Hill.
- Guyton, C. A & Hall, E.J (2017). Text Book of Medical Physiology (13th ed.). Philadelphia: Elsevier Saunders.
- Physiological Reviews available at: Physrev.physiology.org
- WHO Coronavirus disease (COVID-2019) situation reports. April 3, 2020.
This article will contain a little detailed medical information and terminologies that I will do well to explain to them to favor all my readers. This article is not written to scare or put fear among persons diagnosed with the virus, but it rather focuses on educating and providing you with all the necessary information needed to guide and protect you from being affected by the virus.
This content is for informational purposes only and does not substitute for formal and individualized diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed medical professional. Do not stop or alter your current course of treatment. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
© 2020 Richard Asiedu