As of the writing of this article, the 2019-2020 Coronavirus disease (COVID-19) pandemic has caused worldwide social and economic upheaval. Almost every country has mandated some level of social lockdown, severe travel restrictions have been placed between many nations (with mandatory quarantines of up to two weeks for those that do choose to travel), and economic output worldwide has been reduced to a crawl. With its increased prevalence in our collective thoughts, many people are now learning more about viruses (and exponential functions) than ever before. For the casual passerby, this flurry of new information may be daunting. Here, we’ll attempt to address some of these questions and help you be more informed on the current pandemic situation. There will also be discussions involving terminology surrounding this virus, what is a coronavirus, and why coronaviruses will continue to be a part of human life, albeit not always to this degree of disruption.
Terminology
Many similar-sounding terms have been thrown around about the current pandemic, and this can lead to significant confusion. Let’s discuss and clarify some of these terms here.
An epidemic is the spreading of disease through a specific region, population, or community. When this spread reaches beyond just one place or one population, then it has the potential to become a pandemic. The pan– prefix comes from Greek, meaning “all” or “everything”; so a pandemic would be an epidemic on a global scale. The words outbreak and endemic have also been used. If something is endemic, that means that is usually associated with a specific region. For example, malaria is endemic to Africa, as that is where it is typically found, and it probably will not be going away from that region anytime soon. An outbreak is when there is a greater than normal instance of a disease somewhere, regardless of whether it is endemic or not. If a student with chicken pox comes to school and gives a bunch of other student’s chicken pox, that could be considered an outbreak of chicken pox.
As this particular virus is a brand-new strain, it is not endemic to any location. There was initial an outbreak in the region of Wuhan, as many people got sick very quickly in a small area. As the outbreak spread and began infecting more and more people, not just in a part of the city but all over the city and beyond (but not too far out of Wuhan), it morphed into an epidemic. Once this virus spread beyond China and into the broader world, it eventually gained the status of pandemic. There is no hard border between these three terms, and they can be used interchangeably in certain situations, hence why these terms seem confusing or contradictory at times.
Additionally, we should discuss the terminology surrounding the virus itself. The three terms we’ll discuss are coronavirus, COVID-19, and SARS-CoV-2. The terms coronavirus is for the family of viruses that cause diseases in mammals (including humans) and birds. These viruses include not just the current outbreak but also previous viruses including SARS and MERS. SARS-CoV-2 is short for “severe acute respiratory syndrome coronavirus 2” which is the name of the specific coronavirus that is causing the world so much havoc as of late. The disease that this virus causes is called COVID-19, which is short for the “Coronavirus disease 2019”; this encompasses the symptoms and bodily response that occurs when someone is infected with SARS-CoV-2.
In summary, coronavirus is the family name of this virus, SARS-CoV-2 is the name of the specific virus that is causing the current pandemic, and COVID-19 is the disease that is caused by this specific virus.
Discovery and related viruses
The first members of the coronavirus family were initially discovered in animals. One of the first is the infectious bronchitis virus (IBV), which was isolated from chickens in the 1930s. A particularly virulent strain, outbreak have caused significant economic damage to the poultry industry. Other such animal coronaviruses include the Mouse Hepatitis Virus (MHV), the transmissible gastroenteritis virus (TGEV) affecting pigs, as well as feline and canine related coronaviruses. The latter was first discovered in 1971, after an outbreak among German sentry dogs.
The first human cases involving coronaviruses were not detected until the 1960s. Since then, a number of outbreaks of particularly strong coronaviruses have caused international concern, examples of those being the SARS and MERS outbreaks of recent memory. In general, coronaviruses are not particularly strong, and do not cause much turmoil; coupled with rhinoviruses, these two classes of viruses make up the majority of cold and flu cases during the colder months of the year. It is by the process of evolution, and a bit of bad luck, that these coronaviruses mutate into deadlier forms of themselves.
Why Coronavirus?
The name “corona” comes from the shape of the virus when viewed under an electron microscope, a powerful microscopy technique to study very small objects. The structure of the virus, a ball-shape with protruding anchor proteins, makes it look like the stellar corona, which surrounds our sun.
How does it infect cells?
Viruses wreak havoc by hijacking our cellular machinery to produce more of themselves. First, coronavirus has to break-in. This is done by the protein spikes that exist on the viral surface. These spikes latch onto complementary receptors that exist on the host cells; once this is done, the virus inserts its contents (its RNA) into the cell. Though the exact mechanism for coronaviruses is not known, there are two options. The first option is that the viral casing could fuse directly with the cell wall, releasing its RNA free into the cellular space. The other option is the virus could transport its RNA within an endosome formed from the cell wall. Once the RNA is inserted, this is transcribed by the molecular machinery within the cell to make more of itself, to begin the process all over again.
How does an animal virus come to infect humans?
Coronaviruses belong to class of zoonotic viruses, meaning that they are of animal origin; these viruses can jump from animals to humans. Viruses mutate very quickly, multiple times within a year, which is the cause of the yearly cold and flu cycles; this is why we need a new vaccine every year for the flu, as the virus that year is a new strain, with slightly altered genetic coding. If animals and human work close together, these mutations that cause cyclic cold and flu seasons can also make the virus transmittable between species, thus the jump from animals to humans. Wherever humans and animals work together, be it in predator-prey relations (such as hunting animals), economic reasons (raising animals for meat or their by-products, as well as animals as transportation or farm equipment), as companions (pets), or in research, there will always be the risk of a viral jump from animals to humans. Once the virus jumps species, the spread of that virus within the second species is a real possibility. However, just because a virus can transmit between a species, doesn’t mean that it will lead to a pandemic.
What makes this current coronavirus strain so bad?
For a virus to reach pandemic proportions, it needs to balance its lethality and its ability to spread. Most viruses that cause the common flu are weak by comparison, but they spread easily within the population partly due to their weak nature. People that have relatively mild symptoms, who might still be contagious, could still go about their lives, further spreading the virus. On the other hand, more deadly coronaviruses such as SARS and MERS are either not as easily transmittable or kill their hosts too quickly, removing further spread potential. SARS is an example of a coronavirus with a high mortality rate at around 9.5%, but with low spread and infection rates, with only around 8000 confirmed cases worldwide. No new cases for this virus have been reported since 2004. MERS is another example of a deadly but low spread coronavirus, with a mortality rate of almost 35% among 2519 cases since 2012. No evidence of asymptomatic spread has been identified, and human-to-human transmission has only been observed with close, continued contact with severely ill patients.
On the other hand, the spread of COVID-19 has been accelerated by its ability to be spread by not only symptomatic patients, but also those that are infected with the virus but do not exhibit symptoms (asymptomatic). This is one of the major reasons why many nations have instituted 14-day isolation periods for those that arrive from abroad. If a person is infected, they will run through the course of the virus within that time, regardless of whether they show symptoms. Without these measures, each new case of COVID-19 has the potential to infect up to an additional four people. Though this may not seem like a large number, to reach ~2,000,000 infections (the current confirmed numbers worldwide as of the writing of this article), this process would only have to repeat about 10 times. With a mortality rate approaching 6% and ease of transmission due to a long contagious period and asymptomatic/mild symptoms carriers, COVID-19 might be the pandemic to define our generation.
What makes a disease?
In order for a disease to spread there needs to be three elements; susceptible host (humans), agent (SARS-CoV-2 virus), and environment (air). These elements are called the disease triangle. To address a disease public health professionals can address any of these three elements. Vaccines reduce susceptible hosts by building the immunity of a community. Cleaning surfaces and using air purification systems keeps the environment clean, reducing the spread.
How do we slow and stop the spread?
As mentioned above, one of the biggest issues with this current pandemic is the ability for this virus to be spread by people with little to no symptoms. To understand the spread of this virus among the population, and to quantify just how much of the population has been infected, rapid and comprehensive screening needs to take place. One such solution for this is the COVID-19 antigen rapid test and COVID-19 antibody rapid test, which is a fast, cartridge-based test to identify the coronavirus viral antigen or the IgG and IgM antibodies. Please contact us to get a hold of these rapid testing kits to help mitigate the spread of this pandemic!
Please visit the WHO official site for latest updates on COVID-19 outbreak.