✍️ Dr.Niranjan Koirala Ph.D (Gandaki Pradesh)
SARS-CoV-2 (Covid-19) belongs to the coronavirus family along with SARS-CoV (2003) and MERS-CoV (2012). Among all these positive sense single stranded RNA Corona viruses, Covid-19 is the most infectious (pandemic) but with low lethality (2 %) followed by SARS-CoV (10 %) and MERS-CoV (32%). Covid-19 primarily infects lungs and in majority of the cases (80 %) exhibit mild symptoms like fever, dizziness, headache, breathelessness, dry cough, fatigue, loss in smell and taste. Around 15 % seems to have pneumonia, 5 % will suffer organ failure like respiratory failure and 2 % cases leads to lethal death. There are certain underlying problems that leads to fatality such as hypertension, diabetes, cardiac problems, respiratory issue, individuals on immune suppressants, old generation with low immunity.
Covid-19 infection can be categorized into four different stages. In the first stage the infected person may not exhibit any of the typical symptoms (asymptomatic carriers). In the second stage the infected person will show mild fever, cough, headache, and upper respiratory tract infections. The symptoms are more pronounced in the third stage that may require hospitalization, and in the final fourth stage the patient shows severe problems including pneumonia and respiratory distress which may eventually lead to the death of the individual.
Covid-19 directly impacts the lungs and damages the alveoli (tiny air sacs). The function of the alveolus is to transfer oxygen to the blood vessels. These blood vessels or capillaries carry the oxygen to the RBCs (Red blood cells). It is the RBCs that finally deliver the oxygen to all the internal organs in the body. The virus works by damaging the wall and the lining of the alveolus and capillaries. The debris from the damage, which is plasma protein accumulates on the alveolus wall and thickens the lining. As the walls’ thicken, the transfer of oxygen to the red blood cells is impaired. The thicker the wall gets, the more difficult it gets to transfer oxygen to the red blood cells, which causes difficulty in breathing as the body is running short of oxygen. And the lack of oxygen to the internal organs results in a deficit in the body and impairs the functioning of the organs. As the oxygen carrying capacity of the RBC is compromised aerobic respiration is hindered resulting to low energy ATP production then required by the body to function. At the same time due to low level of oxygen the anaerobic respiration increases leading to the accumulation of lactic acid which results in the body pain and organ failure.
The first response of the body is to destroy the virus and prevent its replication, but if the individual has weaker immunity then the body is unable to stop the virus, and this aggravates the crisis Pneumonia. As the air sacs are damaged, there is an influx of liquid which is mostly inflamed cells and protein and this fluid build-up leads to pneumonia. This further impairs the oxygen intake by the lungs and hinders the oxygen exchange. Due to the novelty of the Covid 19 strain, there is no immediate treatment to directly cure pneumonia in Covid 19 patients and are mostly given supportive care.
There are some key indicators the medical practitioners use to judge the onset and severity of Covid-19 infections: Hypoxia-Low oxygen levels in the blood, due to damage to the alveolus; Breathing difficulties and shortness of breath; Chest x-rays of the lungs exhibit an opaque and glassy look against the black background; Deterioting symptoms over the course of time, from the day of detection of the virus.
Dr. Niranjan Koirala, Nepal born researcher earned his Ph.D. from South Korea and double Postdoctoral fellowships from UNAM, Mexico and UM, Macau SAR, China. His research interest is in the field of pharmaceutical engineering, pharmaceutical/medicinal chemistry, natural products drugs discovery, functional foods, diabetes, metabolic disorders and biofuels.