By Charles Nicolson
The previous article published in the August issue of RACA referred to the recently discovered Corona D-19 virus which has dominated headlines worldwide since the end of January this year when it began to spread out from China causing epidemic levels of infections in many countries.
Coronaviruses are, in fact, a large family of viruses which are the cause of respiratory infections ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS).
Another widespread corona-type viral disease is AIDS (acquired immune deficiency syndrome) which often develops relatively soon after infections by HIV (human immunodeficiency virus) although it may remain dormant within a human body and only become active after many years. In common with almost all diseases caused by viruses, there is not yet a cure, as such, for AIDS. However, treatment programmes with suitable vaccines can substantially reduce the progress of the disease and also prevent subsequent complications from developing.
Figure 1: Images of two types od Corona viruses. Covid-19 is image (a). Image credit: FDA ida gov
Now that the newest coronavirus disease, referred to as Covid-19, has become a world-wide addition to all the other coronavirus type infections, it is expected that the primary countermeasures against attacks by Covid-19 will continue to depend on keeping new infections as low as possible until an effective and safe vaccine has been developed and put into production. At the time of writing, progress in both testing and manufacturing various types of vaccines is reportedly advancing at unprecedented rates due to world-wide international collaboration and cooperation which includes China, the UK and the US.
There are currently ten experimental vaccines undergoing field trials and several more types are expected to become available for trials after initial laboratory testing has been completed. However, vaccines are essentially defensive agents which interfere with the mechanisms by which viruses enter and react with animal and human cells. Vaccines will help to limit total numbers of Covid-19 by preventing transmission and spreading by human bodies. The answer to the question as to how long are we going to have to live in this new “coronaworld”? would therefore seem to be – probably for the foreseeable future.
Figure 2: Human Immunodeficiency Virus (HIV). Image credit: FDA ida gov
Looking for up-to-date information on coronaviruses, one is confronted by articles, analyses and opinions containing a mass of technical terms familiar only to people who have at least a basic knowledge and understanding of this particular area of microbiology. This is also evidenced in general print and electronic media which cover news of effects and consequences of infected people but present virtually no information on characteristics and properties of the virus itself. One of the frequently used technical terms is ‘genome’ which is not only used in microbiology but widely used throughout the whole subject of biology as the detailed listing of the complete set of genetic information of any biological organism.
A high-quality, easy-to-read article entitled “Genomic Study Points to Natural Origin of Covid-19” was recently posted by Francis S. Collins, M.D., Ph, D. who was appointed as the 16th Director of NIH (National Institutes for Health research in the USA) by President Barack Obama in 2009 and continues to serve in this capacity under the administration of President Donald Trump. The opening two paragraphs are as follows.
“No matter where you go online these days, there’s bound to be discussion of coronavirus disease 2019 (COVID-19). Some folks are even making outrageous claims that the new coronavirus causing the pandemic was engineered in a lab and deliberately released to make people sick. A new study debunks such claims by providing scientific evidence that this novel coronavirus arose naturally.
The reassuring findings are the result of genomic analyses conducted by an international research team, partly supported by NIH. In their study in the journal Nature Medicine, Kristian Andersen, Scripps Research Institute, La Jolla, CA; Robert Garry, Tulane University School of Medicine, New Orleans; and their colleagues used sophisticated bioinformatic tools to compare publicly available genomic data from several coronaviruses, including the new COVID-19.”
The international research team began by studying the sections of the coronavirus genomes which cause the spikes that give these viruses their distinctive appearance resembling crowns – the word ‘corona’ being the Latin word for ‘crow’. All coronaviruses use spike -type proteins to penetrate and infect cells of organisms and over time, the various coronaviruses have constructed their own spike proteins so that they are different from each other. These differences can be seen as defined in their genomes.
The genomic data of the new coronavirus responsible for Covid-19 demonstrates that its spike protein enables this coronavirus to bind to a specific protein on human cells called angiotensin converting enzyme (ACE2). This is a similar activity that another coronavirus has that causes severe acute respiratory syndrome (SARS) in humans.
Previous computer models had predicted that this new type of coronavirus would not bind to ACE2 as well as the SARS virus. However, the researchers found that the spike protein of the new coronavirus actually bound far better than the computer predictions providing strong evidence that the new virus was not the result of any deliberate manipulations in a laboratory. In fact, the research team concluded that any bioengineers trying to design a coronavirus that threatened human health would be very unlikely to have chosen this type of conformation for a spike protein.
The researchers went on to analyse genomic data related to the overall molecular structure, or what is called the ‘backbone’ of the new coronavirus. Their analysis showed that the backbone of the new coronavirus’s genome most closely resembled one of a coronavirus discovered in a bat after the Covid-19 pandemic began. However, the region that binds ACE2 indicated a novel virus found in pangolins, also called scaly anteaters. These findings are strong evidence that the coronavirus that causes Covid-19 originated in nature. In the event that the new coronavirus had been deliberately manufactured in a laboratory it is far more likely that the backbones of coronaviruses already known to cause serious diseases in humans would have been used for this purpose.
“In common with almost all diseases caused by viruses, there is not yet a cure, as such, for AIDS.”
The researchers were not able to provide a direct answer as to what the natural origin of the novel coronavirus COVID-19 is but proposed two possibilities.
The first is that as the new coronavirus evolved in natural hosts such as bats or pangolins in which the spike proteins mutated to be able to bind to molecules similar in structure to the human ACE2 protein. This proposal would fit in with the more recent outbreaks of coronavirus-caused disease in humans, such as SARS, which arose from civet cats and Middle East respiratory syndrome (MERS), which had proliferated in camels.
The other proposal is that the new coronavirus was transmitted from animals into humans before it had become capable of causing human disease. Then, as a result of gradual evolutionary changes it gained the ability to cause serious life-threatening disease and began to spread out by transmitting from human-to-human.
Both of these possibilities propose a natural origin for Covid-19 which Dr Collins believes is “a good thing because it helps us keep focused on what really matters: observing good hygiene, practicing social distancing, and supporting the efforts of all the dedicated health-care professionals and researchers who are working so hard to address this major public health challenge”.
One further positive step in the current Covid-19 saga is that New Zealand appears to have won the battle against the virus after health officials stated that the last-known infected person had recovered.
Francis S. Collins, M.D., Ph, D
Prime Minister, Jacinda Ardern, said that New Zealand had halted the spread of the virus but she cautioned against over-confidence. “We are confident we have eliminated transmission of the virus in New Zealand for now, but elimination is not a point in time, it is a sustained effort,” she said at a news conference. “We almost certainly will see cases here again, and I do want to say that again, we will almost certainly see cases here again, and that is not a sign that we have failed, it is a reality of this virus. But if and when that occurs, we have to make sure—and we are—that we are prepared.”
Although there are still some restrictive border regulations, commentators have noted that two main factors have helped New Zealand. These are its isolated location in the South Pacific which gave it vital time to note the devastating spread of the virus in other countries and the decisive action by Ardern in imposing a strict lockdown early in the outbreak. Hopefully this achievement by New Zealand will spur on other countries to achieve similar successes.