Note: This article first appeared on EDM Digest.
By Dr. Dena Weiss
Faculty Member, Criminal Justice, American Military University
Viruses are microscopic organisms that must live and reproduce by feeding on a human, animal or plant host. Coronaviruses target the respiratory system of humans and are transmittable among individuals.
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How Does the Coronavirus Attack the Body?
Respiratory viruses such as COVID-19 typically penetrate the host body by entering through nasal passages and the mouth. Coming in contact with COVID-19 particles by handling a contaminated object and then touching other body orifices, such as the eyes, can also spread the virus.
Some viruses such as measles have a stronger transmission radius, but COVID-19 is believed by the Centers of Disease Control and Prevention (CDC) to have “short-range transmission” of less than three feet under most circumstances. Current recommendations are to keep a distance of six feet from other people, but there is no scientific data corroborating safe distances and many factors come into play.
Once the virus enters the body, its genetic material is injected into the host’s cells. That destroys the host cells and causes the virus to reproduce within the host’s body, resulting in further cell destruction.
The genetic material that is replicated is a single long RNA strand. The powerhouse enzymes that initiate the replication of these RNA strands are called polymerase.
German researchers identified the corona polymerase in April of 2020. The research results assisted in the development of antiviral drugs such as Remdesivir that block the enzyme from replicating.
What Is a Virus Mutation?
Virus RNA strands consist of a sequence of nucleotides that form a chain. The chain includes a sugar molecule and 4 base pairs:
- Adenine (A)
- Guanine (G)
- Cytosine (C)
- Uracil (U)
These bases exist in a variety of combinations much like a barcode. A mutation can be as complex as multiple changes of bases in sequence or the simple replacement of an Adenine for a Guanine along the chain.
Why Do Viruses Mutate?
The human body develops antibodies to fight foreign invaders such as viruses. The antibodies attach to the protein shell of the virus, inhibiting it from penetrating the host cells. In response, the virus will change its surface structure slightly, so that it is unrecognizable to the antibodies and can continue to attack the host. This type of adaptation happens routinely with influenza viruses, which is why the flu continues to be an ongoing health threat.
Some viruses that are prominent in animal species have exhibited the ability to mutate in order to transmit from animal to humans. Examples include:
- Measles, which may have originated in cattle
- Influenza, which originated in water birds
- HIV-1, which originated in chimpanzees
- SARS, which originated in bats
However, RNA viruses do not always mutate effectively. Sometimes the mutation occurs accidently because there is no proofreading mechanism to make sure the RNA sequence is repeated properly as well as no repair mechanism like in DNA strands.
The coronavirus is a powerhouse with its large infrastructure. It appears to be “ignoring the RNA virus playbook” due to the newly discovered proofreading mechanism.
Because coronaviruses have developed genetic proofreading mechanisms, changes in sequence are rare. However, a mutation known as D614G has been found on the virus surface in recent COVID-19 patients. The mutation is a simple replacement of adenine (A) for guanine (G).
Nicknamed the “G” variation in the science community, the mutated cells appear to have the ability to invade human cells more effectively. Jeremy Luban of the University of Massachusetts Medical School asserts the mutation may increase the infection rate of the coronavirus by 3 to 10 times.
Although empirical testing is still going on, the “G” mutation was found to settle in the higher upper respiratory tract (nasal cavity and mouth) in higher concentrations than other regions of the body. This leads to speculation that spread may be easier through talking and sneezing.
Virus mutations vary in significance but are critical for scientists to detect for our health and safety. Some mutations trigger an easy fix in an individual’s immune system response, but others may target additional organs in the body. The evolution of a virus can impact development of successful vaccinations and the stability of treatment strategies.
About the Author
Dr. Dena Weiss is an associate professor at American Military University, teaching courses in criminal justice and forensic science. She recently retired after working 24 years as a crime scene investigator and fingerprint examiner for a central Florida police department. Prior to that position, she was a serologist for the Florida Department of Law Enforcement. Her court experience includes testifying in more than 200 federal and circuit court cases in over 15 Florida counties.
Dr. Weiss is also an active member of the Florida Emergency Mortuary Operations Response System (FEMORS). Her educational background includes a bachelor’s degree in chemistry and sociology and a master’s degree in forensic science from Virginia Commonwealth University, as well as a Ph.D. in business administration with an emphasis in criminal justice.