What is a virus? Viruses are microscopic parasites that are usually much smaller than bacteria and consist of genetic material (either DNA or RNA) protected by a protein coat or a lipid bilayer. They lack the ability to reproduce outside of a host and as a result must hijack the reproductive systems of cells through fooling receptors on the cells' outermost layers and using their host's reproductive systems to produce more viruses. There are many debates as to whether or not viruses are alive because they are not made of cells, often do nothing besides lie dormant to survive, and canot reproduce on their own.
What is a coronavirus? Coronaviruses are a large family of viruses which cause mild to severe respiratory illness. There are hundreds of coronaviruses, but only seven have been known to infect humans- three of which cause major disease (SARS-Cov-1, MERS-CoV, and SARS-CoV-2). Coronaviruses were first discovered in domestic poultry, and characterized in humans in mid-1960 as the cause of the common cold.
There are four categories of coronavirus- alpha, beta, gamma, and delta. Alphacoronaviruses and betacoronaviruses infect only mammals, whereas gammacoronaviruses and deltacoronaviruses affect poultry and some mammals. Alpha and beta coronaviruses are the only types known to infect humans.
Electron Microscope generated image of SARS-CoV-2.
What is SARS-CoV-2? SARS-CoV-2 stands for severe acute respiratory syndrome coronavirus and is the virus that causes the disease COVID-19. SARS-CoV-2 is a coronavirus, which means that it looks almost like a solar eclipse with its shape and has spike proteins around the outside of its protective phospholipid bilayer. SARS-CoV-2 is similar to the SARS-CoV virus which caused the SARS outbreak in the early 2000s and affected many parts of the Eurasian continent and North America. The novel SARS-CoV-2 virus is much more widespread and has affected many more people than SARS-CoV.
How does SARS-CoV-2 infect our bodies? There are three main antigens in the SARS-CoV-2 virus (essentially toxic molecules that cause an immune response): the spike-protein, the membrane-protein, and the nucleocapsid-protein. These antigens bind to a receptor protein called ACE2 in human respiratory cells (usually epithelial cells, or cells that line the outside of organs). The virus then uses the information encoded in its genetic material to reproduce with the cells' "machinery" through the lytic cycle (which destroys the host cells). The copies of this virus then infect more cells, spreading the virus throughout the body.
How does the virus spread? The virus is spread in three main ways, respiratory, aerosol and contact transmission. Respiratory transmissions happen when someone sneezes or coughs. Aerosol transmission happens after someone sneezes or coughs and their germs remain in the air. Contact transmission happens when germs are on a surface and someone touches that surface and then their face or another area of their body, which is known as self-inoculation.
Why is this virus so difficult to treat? The virus is difficult to treat because it is a novel virus, meaning it is a disease that we have never seen before. Therefore we do not have any treatments that are specific to treating its symptoms and stopping the viral spread within the body. Viruses in general cannot be cured due to their nature, but by bolstering the immune system's identifiers (B-cells with specific antibodies that allow lymphocytes to attack invaders) and defenders (T-cells), one may be able to defeat SARS-CoV-2 through the body's natural defenses and potentially again through the use of memory B-cells.
How can I protect myself from the virus? The CDC, WHO, and healthcare professionals recommend the regular washing of one's hands for 20 seconds, especially after coming in contact with surfaces in public places, coming in contact with people, or just going out in public in general. Masks or face coverings should be worn where effective social distancing is not possible, but it is highly recommended to help prevent the spread of the virus among people. See two videos below, one detailing the effectiveness of hand-sanitizer versus hand washing to combat the virus (spoiler- both work, but wash your hands), and another detailing the effectiveness of masks and how they work.
These videos, from reputable sources Ted Ed and Vox, are really helpful if you would like a more concise overview of safety in video format.
Sources “Coronavirus (COVID-19) Frequently Asked Questions.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 22 Apr. 2020, www.cdc.gov/coronavirus/2019-ncov/faq.html#Coronavirus-Disease-2019-Basics.
“Coronaviruses.” National Institute of Allergy and Infectious Diseases, U.S. Department of Health and Human Services, www.niaid.nih.gov/diseases-conditions/coronaviruses.
“Coronavirus.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 15 Feb. 2020, www.cdc.gov/coronavirus/types.html.
Neuman, Benjamin. “Virologist Explains What The Coronavirus Does to Your Body That Makes It So Deadly.” ScienceAlert, www.sciencealert.com/why-is-this-coronavirus-so-much-more-dangerous-a-coronavirus-expert-explains.
Cain, Michael L., Robert B. Jackson, Peter V. Minorsky, Jane B. Reece, Lisa A. Urry, and Steven A. Wasserman. "The Immune System." Campbell Biology, edited by Wilbur, Beth et al., 9th ed., Pearson Education Inc, 2011, pp. 929-945.
Cain, Michael L., Robert B. Jackson, Peter V. Minorsky, Jane B. Reece, Lisa A. Urry, and Steven A. Wasserman. "Viruses." Campbell Biology, edited by Wilbur, Beth et al., 9th ed., Pearson Education Inc, 2011, pp. 381-393.