Viruses 101 and the Body’s Battle Against These Relentless Invaders
Joseph R. Anticaglia MD
Medical Advisory Board
In the film, “Invasion of the Body Snatchers,” several people in the fictitious small town of Mira, California visit psychiatrist, Dr. Miles Bennell. They have similar complaints: the personality of their loved ones have been hijacked by some outside force changing them eventually into emotionless, robotic humans.
Initially, the doctor dismisses the patients’ concerns due to anxiety. However, the doctor and others discover that their concerns are valid. The outward appearance of the loved ones remain basically the same, however, their psyches have been re-educated. The internal workings of their human spirit have been brainwashed causing them to take on a new persona. It’s as if a loved one suddenly becomes cold and indifferent. How did this happen?
In this sci-fi film, extraterrestrial forces have caused plant pods to descend on Mira, California. The pods invade the bodies of the people in this community while they are asleep. Once inside the living body, the seeds with their toxic chemicals multiply exponentially. The invasion overwhelms the body’s defenses and transforms humans into this new reality, unemotional creatures—pod people. Well, what does this have to do with viruses?
Viruses
Viruses can be thought of as outside forces that penetrate, outsmart and overwhelm the body’s natural defenses. They can remain dormant in the body until something triggers their virulent — harmful behavior. Active viruses can multiple thousands and thousands of times and overwhelm the body’s defenses. And when this happens, it can transform a person’s psyche.
Depending on their virulent make-up, type and numbers, viruses can cause mild symptoms such as that of the common cold or they could have deadly consequences due to the influenza virus, the Ebola virus and more recently, the novel Coronavirus.
Viruses are astonishingly small. They range in size from about 20 to 400 nanometers in diameter. Scientists need to use an electron microscope to visualize them because an ordinary light microscope cannot detect them. Their small size can pass through filters that are effective in preventing even the smallest bacteria from passing through such filters.
They have a dramatic ability to replicate (reproduce-increase in numbers), commandeering and overwhelming the body natural defense mechanisms; and at times, become brutally lethal. They come in different sizes and shapes and target different organ systems.
Source: Wikimedia commons
All true viruses contain a nucleic acid core—either DNA (deoxyribonucleic acid) or RNA (ribonucleic acid)—and protein. The nucleic acid makes each virus unique.
Some viruses specialize in attacking the respiratory system, others the gastrointestinal system and so forth. When scientists think they have discovered an answer to combat their virulence, the viruses often mutate — change size, shape and characteristics. The common cold is a frustrating example of this viral Gordian knot. Scientists to date have been unsuccessful in developing a vaccine to counter the common cold virus.
History of the First Virus
It was in the late 18th century when the work of two men contributed to the discovery of the first virus. In 1892, scientists Dimitri Ivanovsky and in 1898 Martinus Beijerinck observed that an agent of the tobacco mosaic disease passed through porcelain filters whereas bacteria did not pass through such filters. When this slimy, filtered material was placed in contact with tobacco leaves, it caused tobacco mosaic disease. The conclusion: the material that passed through the filter contained a distinctive pathological agent (a disease causing substance) and it was not bacteria. The culprit was subsequently identifies as the tobacco mosaic virus.
The name virus, given to the above disease causing substance, was taken from the Latin word meaning slimy liquid. Many considered the observations of the two scientists as the birth of Virology — the science that deals with the study of viruses.
Since the findings of the above scientists, the term virus has been restricted to “filterable agents that require a living host for propagation.” The groundbreaking work of the above researchers established a pathway for other scientists to follow which resulted in other viruses being discovered. For example:
- 1901 — Yellow fever virus
- 1903 — Rabies
- 1906 — Variola virus
- 1908 — Polio virus
- 1931 — Swine flu virus
- 1933 — Human Influenza virus
In the 1950’s several important human viruses were discovered; including the measles virus, the varicella zoster virus, rhinoviruses that cause the common cold and respiratory (syncytial) viruses. In 1963 Hepatitis B virus and in 1983 the HIV virus were discovered. In the second half of the 20th century, different viruses have been discovered in every decade.
In the early part of the 21st century, the world experienced and identified — Severe Acute Respiratory Syndrome (SARS). It is a respiratory illness caused by coronavirus (SARS-CoV) that first appeared in Asia in 2003. This contagious, viral respiratory disease spreads through droplets that enter the air when someone with the disease coughs, sneezes or talks. It caused 774 deaths or about one in ten people who were infected with the virus.
Middle East respiratory syndrome, MERS, is a viral respiratory disease caused by a coronovirus (MERS-CoV). Symptoms include shortness of breath, fever, cough and diarrhea. It was first identified in Saudi Arabia in 2012 According to the World Health Organization, approximately 35% of reported patients with MERS-CoV have died or 858 deaths since September 2012.
More Characteristics of Viruses
All viruses need a living host cell to multiply (obligate parasites). They’re called either “DNA virus” or “RNA virus” and the virus cannot contain both DNA and RNA. Viruses are non-cellular and are surrounded by a protein envelop called capsid. They don’t increase in size but they do increase in number.
The ability of viruses to cause mayhem depends in part on their virulence, their ability to mutate and on the resistance of the individual. If the host living cell swells to capacity and cannot tolerate more pressure, as noted above, the cell bursts, freeing viruses to circulate throughout the body targeting other cells. Antibiotics have no effect on these rampaging viruses.
In short, viruses don’t have the biologic machinery, namely, the ability to thrive on their own. Therefore, they have to sponge-off living cells to get nutrition and to increase in numbers. Like other obligate parasites, they give nothing back to the host cells. In the laboratory viruses have to suck up nutrition from living cells. In contrast, bacteria and fungi can be cultivated and live in the laboratory and reproduce on non-living nutrient agar.
Viruses infect people, animals and plants at any moment of day, in any place and at any time of the year. In 2020, the world is experiencing another worldwide outbreak associated with coronavirus. The number of cases afflicted by this novel coronavirus is on the rise. It’s infecting more people, causing more deaths and in more countries. Hopefully, we have the wherewithal to repel these relentless invaders.
References
- Center for Disease Control and Prevention — CDC; Severe Acute Respiratory Syndrome (SARS)
- H. Lecoq; Discovery of the first virus, the tobacco mosaic virus: 1892 or 1898? C R Acad Sci III. Oct 3, 2001
- Lumen Learning, Boundless Microbiology; Overview of Viruses
- Center for Disease Control and Prevention — CDC; Middle East Respiratory Syndrome (MERS)
This article is intended solely as a learning experience. Please consult your physician for diagnostic and treatment options.