Post created by Calysta
Do you wonder what unseen enemy has imprisoned millions of people around the world? What miniscule protein-covered bag of RNA--nonviable without a human host—has driven doctors and nurses to shield themselves behind protective suits? What infinitesimal invader impelled people to point fault at U.S. presidents over the past two decades? It is SARS-CoV-2, novel coronavirus, more commonly known as COVID-19.
Having infected over 2.3 million infections worldwide, COVID-19 has caused almost 160,000 deaths and has brought modern medicine to its knees. According to Harlan Krumholz of Yale University, “Its ferocity is breathtaking and humbling.” Unlike most viruses which target one specific organ system, this culprit attacks multiple organ systems: it is pan-systemic. Similar to its close cousin, severe acute respiratory syndrome (SARS) epidemic of 2003, COVID-19 attacks the respiratory and neurologic systems; however, it also attacks the cardiovascular, immune, gastrointestinal and urinary systems. Much is still being learned about the novel virus in the midst of the rising slope of victims. The war is on against this pathogen whose strategic movements continue to baffle medical scholars.
A stealthy approach…
COVID-19 has been found to be extremely contagious, largely because it is transmitted through air via infected, asymptomatic persons. Once the virus is inhaled, it finds a home in human cells rich in a cell-surface receptor called angiotensin-converting enzyme 2 (ACE2) which can be found in the linings of the lung, blood vessels, heart, and lower digestive tract. ACE-2 is a receptor for a hormone, angiotensin, used to regulate blood pressure. Most commonly, the offender lands in the nasal passages, uses the ACE-2 receptor to gain entrance into the cell where it commandeers the cell’s machinery to silently replicate itself. For about a week, the virus replicates, preparing for the attack, though its host has no symptoms and unknowingly sheds virus to those around him. After this incubation period, the host develops cough, fever, body aches, and possibly loss of smell and taste.
The war is on!
About this time the immune system either beats the attack or the virus advances down the respiratory system, down to the alveoli where the battle rages. The body brings in the artillery, summoning inflammatory cells, and killing the virus, leaving behind a field of pus which blocks oxygen from coming through. By this time supplemental oxygen may be needed by nasal prongs or by ventilator.
Launching a retaliatory attack
In an effort to fight the enemy, the body may resort to something called a cytokine storm—a destructive overreaction of the immune system—causing leaky blood vessels, drop in blood pressure, clot formation, progressing to multi-organ system failure. Cytokine are chemical mediators that help solicit an immune response. In this case, too much of a good thing can become debilitating, causing more complications on the victim—even death.
A pan-systemic battle…
Though the severe acute respiratory distress syndrome is what gets much attention, COVID-19 has slipped through hospital battle lines masquerading as other diseases:
· Some patients have presented as heart attacks, but without the coronary blockage associated with heart attacks. The viral attack, however, is just as deadly, causing grave damage to the heart muscle. Additionally, virus wreaks havoc on the hormones that regulate blood pressure, causing constriction of blood vessels, notably in the lungs, preventing ventilation even with the most sophisticated ventilators.
· Some have presented with strokes and pulmonary embolism. More and more physicians are convinced that causing blood clots is a common modus operandi for COVID-19.
· Some have presented only as severe diarrhea, bringing about concerns on the oral-fecal route of transmission.
· Some have progressed to kidney failure since the kidney cells are high in ACE-2 receptors. COVID patients with associated kidney disease are five times more likely to die than those without.
· Lastly, the villainous bandit finds a way to cross the blood-brain barrier, causing encephalitis and a hyperreaction of the sympathetic nervous system leading to seizures. Some theorize that the break-in happens at the cribriform plate, explaining the loss of smell.
No cure for the common cold
Yes, the common cold is caused by a coronavirus, but this novel coronavirus is not just your average cold—it’s deadly. The race is on to beat this invisible enemy whose impact is mighty and swift. Until then, the battle will continue within the body on multiple fronts—and around the world.
Resources
Google Search, Google, www.google.com/search?q=immune%2Bsystem%2Bfighting&client=firefox-b-1-d&sxsrf=ALeKk00MZoGCPOVOoFoKVha4c_HQjdLCDA%3A1587513096206&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjPv7OR2_roAhVLvJ4KHfIIApcQ_AUoAXoECAsQAw&biw=1536&bih=750&dpr=1.25#imgrc=VmefEyXdAwnuoM.
Wadman, Meredith, et al. “How Does Coronavirus Kill? Clinicians Trace a Ferocious Rampage through the Body, from Brain to Toes.” Science, 21 Apr. 2020, www.sciencemag.org/news/2020/04/how-does-coronavirus-kill-clinicians-trace-ferocious-rampage-through-body-brain-toes