By Victor Dumaguing, MD
MICROBIOLOGY is the study of microbes, divided into cellular microbes-bacteria, algae, archea, protozoa, fungi. Scientists do not consider viruses to be living organisms, they are referred to as “acellular microbes” or “infectious particles” rather than microorganisms.
Complete virus particles called virions are very small and simple in structure. There are several theories as to the origin of viruses but the most plausible is that cells came first and that viruses represent ancient derivatives of degenerate cells or cell fragments. Unlike the other microbes, example bacteria, which are relatively easy to identify with a light microscope it was only in the 1930s with the invention of the electron microscope that the world was able to see viruses.
It is important to emphasize that no type of organism is safe from viral infections; viruses can infect humans, animals, plants, fungi, protozoa, algae. Viruses that can infect bacteria are called bacteriophage.
Viruses have specific properties that distinguish them from living cells. Majority of viruses possess EITHER the double-stranded DNA or the single stranded RNA, unlike living cells which possess both. Viruses are unable to replicate or multiply on their own; their replication is directed and controlled by the viral nucleic acid ( DNA or RNA) once it has been introduced into a host cell. Unlike other microbes, they do not divide by mitosis, meiosis and binary fission, and they do not have the genes and enzymes necessary for production or generation of energy. In other words, intracellular survival mechanisms (absolute necessity of staying inside the host cell) keep them alive.
Viruses are unique in the sense that they are the only ones in this world which are either DNA or RNA containing; all the rest in the animal and plant kingdom have both DNA and RNA.
Viruses are also ultrafilterable – meaning they are so small, and thus can penetrate the membrane of the nucleus of human cells and manipulate, modify and even take over the genetic machinery of the host cells.
Which is the case of the COVID -19 virus, also called SARS-CoV2 which is an RNA virus equipped with the reverse transcriptase, an enzyme so powerful that once it is inside the host cell, it could dictate or, to use another familiar term, hold the host cell hostage into obediently producing more copies of the virus, thus leading to the signs and symptoms of the COVID-19 disease.
In other words, viruses survive and replicate (reproduce) by invading the host (patient) cells by hijacking and commandeering its protein-making machinery – that protein are in the surface of the COVID virus which enables it to invade more of the host’s cells; such surface receptors are found in abundance mostly in the respiratory tract and in the gastrointestinal tracts which explains why most symptoms of COVID-19 are affectations of the lungs like extreme difficulty of breathing, low oxygen levels of the blood which require intubation, as well as intractable loose bowel movement and dehydrating diarrheas.
Lately, clinical experiences of many cardiologists and even neurologists proclaim the presence of receptors of the COVID-19 virus in the heart and brain respectively which might explain the absence of sense of taste and smell in some patients.
As if the onslaught of COVID-19 is not enough in causing havoc and distress to humanity, especially adults – particularly the elderlies – the virus did not spare the children and infants. For some unexplained reasons which bother and bewilder pediatricians, the disease manifests itself in the form of vasculitis, infection/inflammation of the blood vessels very similar to the pathogenesis of Kawasaki disease in which the distal extremities like the toes and fingers bear reddish discoloration and rashes.
Notwithstanding the great strides and breakthroughs in the field of medicine, the fact remains that there is no single medicine to treat and cure COVID-19. The world knows that whenever it’s a viral infection, unless there’s a secondary bacterial infection, antibiotics are not indicated. For the most part, common colds and most viral infections are self-limiting. Just a balanced diet, isolation at home, restful sleep would be enough to bring the patient back to his/her feet. Thus, our medical front liners have come up with a “cocktail regimen” – combination of several drugs; anti-virals, steroids, anti-inflammatory meds like the zumabs to tide over a serious patient back into good health.
Next Week: Is there an Ideal vaccine?