by Tayo Fasuan
So let us get straight to this in order to warn and encourage us in the fight against COVID-19 caused by SARS CoV-2 that just got into our country, Nigeria.
So, why would this Coronavirus be difficult to control.
1. It is an air-borne virus.
In the history of infectious diseases, airborne infections are the most difficult to control, and because of this, respiratory viruses are known to be devastating during their outbreak. Severe Acute Respiratory Syndrome (SARS) was a prime example of this, and its outbreak in 2003 was known to be uncontrollable at the initial stage. The Spanish flu, caused by the influenza virus, another known respiratory virus, in 1918 was recorded to have caused over 200 million deaths worldwide before it was controlled, and all other subsequent influenza outbreaks have been known to be highly uncontrollable. While other infectious agents that are blood-borne and food-water-borne can easily be controlled by avoiding the sources, avoiding airborne infections has proved to be more difficult and trickier.
2. It is an RNA virus.
RNA viruses are arguably the viruses that have caused more devastation in the history of infectious diseases, more than their other counterparts in the DNA family. Influenza, Ebola, Lassa, Coronaviruses, Arboviruses and even HIV are all known RNA viruses with documented history of re-emergence and continually sabotaging efforts to curb their infections. The reason lies in the fact that their genome, which is an RNA, is known to be able to mutate faster than those of DNA viruses. In fact, many studies have shown that when some RNA viruses enter new hosts, they are usually different genomically when they are exiting these hosts. And because of this, targeted preventive and curative measures usually do not work.
3. They use the oral routes as well.
Most infectious respiratory agents have been known to be shed and transmitted from the mouth, especially through salivary spray. This makes these agents even more difficult to control since transmission is now through both cavities (mouth and nostril). The throat (pharynx and larynx) is responsible for this connection, acting as the passageway for air, food and liquid. Its location is behind the nose and mouth, and it connects the mouth (oral cavity) and nose to the breathing passages (trachea and lungs) and the esophagus (eating tube). This now allows infectious fluids from the lungs (the primary place of viral multiplication) to be distributed from both mouth and the nose as aerosols.
But why is Coronavirus seemingly also easy to control?
1. Simple hygienic practices.
Despite the dangerous way respiratory viruses operate, with their established and known ways of disseminating themselves, simple hygienic procedures and practices are known to disrupt and control their transmission. The use of nose and mouth masks, washing of hands, use of sanitisers to wipe hands and surfaces are known to be able to curb their spread by over 90%. Once the virus is disallowed to spread, its devastating effects would be stopped. And since infectious respiratory agents are likely to be acquired outside the body just like food-water-borne agents, then hygienic practices would likely prevent them unlike blood-borne infectious agents.
2. Seasonal Dependence.
Although most studies and researches have shown that respiratory infections are common during cold seasons, a lot of people are still skeptical due to the fact that the viruses can mutate and adapt to hot weathers. While this could be so, the bulk of the respiratory infections still happen during the cold, winter or harmattan seasons, indicating that environmental conditions are huge factors in sustaining their transmission. The reason is that these viruses are generally inactivated by hotter temperatures, rupturing their protective envelopes and denaturing their proteinous coats. Also, the high humidity that is prevalent in hot weathers also makes sure that instead of the infectious particles being airborne and suspended as observed during the dry season, they would have acquired enough moisture to make them fall closer to the ground, hence preventing them from being inhaled or swallowed.
3. Mutation might actually be slower in Coronaviruses.
The coronaviruses have the largest RNA genome known, and because of this, there have been suggestions in many studies that the genome might not be prone to mutation like other RNA viruses. Although, there is yet no evidence about this mutation frequency, the frequency of its outbreak over the years can be pointed out as supporting this claim. After the 2003 SARS outbreak, the next Coronavirus outbreak was nine years later in 2012 in the form of Middle East respiratory syndrome outbreak. And now, seven to eight years after, we have COVID-19 caused by a variant of SARS virus of 2003. If anything is to be deduced about the frequency of occurrence in comparison to other virus outbreaks like those of the arboviruses (another notorious family of RNA viruses) or even HIV whose mutation occurs per seconds, then maybe the virus mutation is not as faster as expected of major RNA viruses then.
While all these points stated might not really be new, we should at least be encouraged that the COVID might yet be defeated.