The Science Of The Virus
A Helpful Primer On What To Do, And What Not To Do
It’s become apparent as we navigate the coronavirus pandemic that there is a gap in understanding the roles and differences between viruses and bacteria.
Both live in and on us, many beneficially and others not so much. Estimates are that for every human cell in our body, there are 10 times as many bacteria. We are dependent on our commensal bacteria to help us with digestion, producing needed vitamins, supporting our immune systems and keeping more harmful bacterial populations in check.
Both bacteria and viruses cause diseases that can be transmitted to other individuals and sometimes other species. Some are specific to a particular animal or species and stay that way, while others can mutate and jump to another or multiple species. This is a vital trait for survival, but not welcome, as with the “swine flu,” measles or the current coronavirus pandemic.
The current coronavirus, officially named SARS-CoV-2, is part of a large family of viruses that are named for their appearance, a halo or crown effect of their protein-lipid coating. Coronaviruses are a huge group and cause a variety of diseases that circulate in animals and people, such as influenzas (human and animal), rabies, hepatitis (human and animal), Dengue fever, polio, smallpox, Feline Infectious Peritonitis and HIV to name just a few. An as-yet unidentified virus is suspected to be the trigger for multiple sclerosis. SARS-CoV-2 is related to the coronaviruses that cause Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS-CoV). The disease in humans caused by SARS-CoV-2 is called COVID-19 and causes flu-like symptoms, from mild-to-severe respiratory illness with fever, cough and difficulty breathing.
Bacteria and viruses are tiny – we cannot see viruses with a microscope and only some bacteria are large enough to see their shape but are still too small to identify their individual species. The biggest difference is bacteria are complex little creatures with a surrounding protective wall of one to three layers. Bacteria can survive on their own without a host for significant periods of time.
Viruses do not have a surrounding structural cell wall and are a package of either DNA or RNA with or without a coat of lipid (fat) and protein molecules. An infective virus (called a virion when not in a cell) is a hijacker – it cannot survive without a host. These viruses only survive on surfaces for varying periods of time, so some move into intermediate hosts that may take them to their appropriate host. Most viruses do cause disease and are very targeted about getting to the specific cells they need in the host’s body. Viruses cannot be treated with antibiotics.
A virion will attach to its targeted cell/s and use the cell’s replication machinery to make new virus particles until the cell ruptures and those particles move to hijack more cells. SARS-CoV-2 targets the cells of the upper respiratory tract and may move to other organ systems by the sheer volume of its reproduction – much is still not known about all its pathology.
The survival time of the SARS-CoV-2 outside of its host when transmitted by coughing, sneezing or transfer from surfaces is highly variable. The good news is that properly and frequently washing your hands with warm water and any soap kills the virus.
Additionally, avoiding touching your face is also hugely effective in preventing transmission, along with wearing masks. Common household cleaners such as dilute bleach and other chemicals also are very effective – just read labels to identify those that do kill viruses versus only bacteria. The CDC COVID-19 site does have links to charts of effective products.
There are significant areas where the disease symptoms caused by either a bacterium or a virus can overlap. For many infections, a virus can cause the first wave of illness and then a bacterium may create further opportunistic disease, such as when you get the flu and then end up with an infection in your sinuses or pneumonia. Most importantly, viruses cannot be treated with antibiotics, while most bacterial infections can be treated with antibiotics or even individualized, genetically engineered viruses called bacteriophages.
The science of virology is still very young and there is much that is unknown – especially when a new virus such as SARS-CoV-2 appears and rapidly goes global. A year or two from now – which seems incredibly long – we will know how to prevent and treat COVID-19.
Wash your hands! Wear your mask! Dispose of gloves and sanitizing wipes properly! Respect social distancing!
Dr. Margot Vahrenwald is the owner of Park Hill Veterinary Medical Center at 2255 Oneida St. For more information, visit www.parkhillvet.com