Understanding COVID19 – I: How Coronavirus Attacks the Body
With more than 2.5 million COVID-19 infections confirmed in 185 countries globally, scientists have made themselves busy in doing clinical trials for vaccines while health officials want to slow the spread with effective policy implementation. Meanwhile for the common public, it is integral to truly know what we are fighting and what is going behind the scenes of the deadly pandemic’s working. In this series of four, we start with explaining the mechanism of Coronavirus and how SARS-COV-2 attacks a healthy human body. Complete Coverage: Coronavirus
Crux of the Matter
Severity Level of COVID-19 The incubation period is the time between the beginning of the infection and the first symptoms appearing, which is five days on average. After this stage, the disease is categorized into three types:
i)Mild Infection: 8 out of 10 people who get this, have fever and cough as the core symptoms.
The fever is a result of their immune system responding to the infection, by sending warning signals to the rest of the body in the form of chemicals called cytokines. This immune buildup leads to body ache and pain. Then the cough is initially dry, caused by the irritation of cells who are infected by the virus.
However, this soon converts into a thick mucus called sputum, which contains dead lung cells killed by the virus.
ii)Severe stage infection: If those chemical signals are continuously sent, too much inflammation can occur, which in turn causes collateral damage throughout the body. This imbalance in immune response leads to inflammation of the lungs and causing a medical condition called pneumonia. This stage is reached by 14% of the patients, according to WHO data.
iii) Critical stage infection: 6% of the overall cases reach this stage, which leads to the death of the patient. Multiple organ failures occur due to the prolonged stage of inflammation in the body, building what is known as the cytokine storm. This, in turn, can lead to septic shock when the blood pressure drops to dangerously low levels, causing shortness of breath and ultimately Acute respiratory distress syndrome (ARDS).
The Route of Destruction: The Infection Begins COVID-19 caused by the SARS-COV-2 virus starts with droplets that originate from an infected person’s cough, sneeze, or breath. These droplets are then transmitted to a healthy person, via air or any contaminated surface.
Once inside, the virus hijacks the healthy host cell’s machinery, making multiple copies of itself and invading receptor cells that are helpful in communicating with outside molecules and regulating blood pressure, namely angiotensin-converting enzyme 2 (ACE2). The thinner branches of the lung’s respiratory tree end in tiny air sacs called alveoli which are rich in ACE2.
The immune system is a host defense system comprising many biological structures and processes within an organism that protects against disease. To function properly, an immune system must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms, and distinguish them from the organism’s own healthy tissue.
Researchers at the University of Virginia School of Medicine have theorized that interferon-gamma (IG), a substance that helps the immune system fight invaders, was linked to social behavior. Meaning based on how friendly you’re feeling could be linked to your immune system!
Peter Doherty and Rolf Zinkernagel jointly received Nobel prize in 1996 for the discovery of how the immune system recognizes virus-infected cells. For his work, Peter Doherty was also announced as “Australian of the year” in 1997.