Medical Wizardry

COVID-19: The Eclipse that Greeted 2020

Vien the wake of the recent outbreak of SARS in Wuhan, the capital of the Hubei province of China. Here are some facts and figures about the coronavirus disease of 2019 (COVID-19).

The 24th situation report submitted by WHO had confirmed that as of the 13th of February 2020, there were around 50,000 confirmed cases worldwide. Though the bulk of these patients belonged to China, there are many cases distributed throughout the globe.

The events since then were fast-paced. COVID-19 was declared a pandemic on the 11th of March 2020.

Since then, the number of cases rose to over 1.2 million within a month (as of the 5th of April 2020), with about 70,000 dead!

Emerging Viruses

2019-CoV is what we in the medical fraternity call an “emerging virus”, which are viruses that appear to scientists unexpectedly or have been discovered for the first time.

The emergence of these viruses can not be explained by any unique mechanism. However, research has shed some light on three main processes that may lead to the emergence of various viruses. They are:

Mutation of the existing virus
Dissemination of the viral disease from a small isolated population
Zoonotic spillover: Spread of existing viruses from vertebrate animals to humans.

Zoonotic Spillover

As mentioned, it is essentially the spillover of a pathogen from the ”natural reservoir” population into the human population. The natural reservoir population includes the animals in which the virus resides hidden. The reservoir population usually remains asymptomatic.

To get a clear view of the concept described above, let us consider a well-known example, which is nothing but the "flu" virus, which has caused multiple epidemics throughout the pages of human history.

Being familiar with the three subtypes (A, B, and C) of Influenza viruses, only type A can produce symptomatic diseases in both animals and humans. And thus, it comes as no surprise that the infamous Spanish flu pandemic of 1918, as well as the Swine flu epidemic of 2009, were caused by an influenza A virus of the subtype H1N1.

One of the hypotheses is that these were caused because of the rich source of natural reservoir available for the transmission of the virus from the zoonotic species to the human race.

With this basic understanding of emerging viruses, let us try and understand the recent COVID-19 pandemic.

The Coronavirus

It is a single-stranded, positive-sense RNA virus that is relatively large with a diameter ranging from 80-220 nm.

It is an enveloped virus that is pleomorphic (meaning it can assume different forms) with “spikes” with club-like or drumstick-like swellings placed at regular intervals over it.

Though the virus multiplies exponentially at 34°C, its infectivity has an inverse relationship at higher temperatures.

Apart from respiratory infections, the coronavirus can also cause outbreaks of gastroenteritis when transmitted via the feco-oral route. This is characterized by non-inflammatory watery diarrhea and is usually self-limiting.

The diagnostic test is an electron microscopic examination of the stool sample from an infected individual. But, it is not mandatory due to the self-limiting nature of the disease.

Structure of the coronavirus; Author: Felipe Esquivel Reed

Fun Fact: Why “Corona”-virus?

Image: Naming the virus

The coronavirus gets its name because of its morphology seen under an electron microscope, which shows projections/spikes on the membrane, creating a halo-like or crown-like appearance (corona, Latin for “halo” or “crown”).

Classifying the coronavirus

The coronavirus contains four main genera:

Alpha
Beta
Gamma
Delta

The beta-coronavirus is the one that has been implicated in the recent outbreak that is said to have started in Wuhan. It goes by various names such as the novel coronavirus, 2019-nCoV, or the SARS-CoV-2.

Chinese horseshoe bats have been implicated as the natural reservoir of a SARS-like coronavirus.

The other carriers of the coronavirus include;

Masked palm civet
Burmese ferret-badger
Racoon dog

Coronaviruses belong to the order, Nidovirales, and have a propensity to cause enteric, respiratory, and neurological infections in domesticated mammals.

History and Speculations

Severe Acute Respiratory Syndrome (SARS)

In November 2002, people in China (especially in Guangdong Province of China) began falling sick of a new respiratory disease. Nothing of this was said by the Chinese authorities until February 2004, when 305 "atypical pneumonia" cases were reported.

It already fled China at that time, when it was transmitted by a Guangdong resident in a Hong Kong hotel to other guests who circulated it to t.

It took only a few months for pneumonia to spread to more than 25 countries in Asia, Europe, and North and South America, thanks to the ease of global travel. The World Health Organization (WHO) released a global warning on SARS in March 2004.

In May, anyone found violating SARS quarantine orders threatened to be executed or jailed for life.

Public health staff reacted quickly, isolating patients and quarantining those who had come into contact with them. This rapid response resulted in quenching the epidemic before it could reach a much larger population due to low infectivity and other characteristics of the SARS virus.

By July 2003, when the outbreak had been declared over, it had spread to 29 countries, killed 774 people, and infected 8,098. Of those killed, 350 were in China, none in the United States.

Two Hong Kong and Shenzhen teams discover a Coronavirus in wild animals gathered in markets in southern China on May 23, 2003.

Species tested positive were the masked palm civet, the Burmese ferret-badger, and the raccoon dog.

Over 10,000 civet cats, a forest animal sold in wild game markets, and a popular delicacy in many restaurants were killed by the Chinese government.

During and after the outbreak, accelerated identification and preventive steps were undertaken. Two examples of protective measures are proactive monitoring of symptoms of fever or respiratory disease at airports and the implementation of SARS-CoV vaccine trials. At the moment, no particular treatment is accepted.

The SARS outbreak in 2003 revealed the ease with which a viral infectious agent would spread to the globe.

It is not clear if SARS-CoV was passed on directly to people (bats are eaten as a delicacy and bat feces are a traditional Asian asthma treatment) or whether they were transmitted to people through infected civets.

Middle East Respiratory Syndrome (MERS)

Under the International Health Regulation (2005), the Republic of Korea told the WHO on 20 May 2015. The Regional Emergence Center was founded by WHO on 28 May 2015, and an event management team was formed.

Image: Electron micrograph of Middle East Respiratory Syndrome virus CoV particles

In June, a joint mission was conducted by the Ministry of Health and Welfare and WHO to assess the risks posed by the outbreak and make recommendations on response measures.

The joint mission was followed by a visit by Dr. Shin Young-soo and Dr. Margaret Chan, then the WHO Regional Director and Director-General, respectively.

Epidemiology

As mentioned above, throughout history, there seem to be two main outbreaks of the coronavirus:

SARS (Severe acute respiratory syndrome)
MERS (Middle East respiratory syndrome)

SARS or SARI (Severe Acute Respiratory Infection)

MERS

How can we protect ourselves from coronavirus?

The WHO has issued a set of standard recommendations to limit the exposure and spread of infections. These include:

Social distancing seems to be the need of the hour.
Frequent handwash by using alcohol-based hand rub or soap and water.
Coughing and sneezing into a flexed elbow or tissue. Following this, the tissue is thrown away immediately and hands are washed.
Avoid close contact with anyone who has a fever and cough.
Self-quarantine if you experience any of the symptoms of the coronavirus infection. Seek help from a medical practitioner in case symptoms worse over the days.
The consumption of raw or undercooked animal products should be avoided.

Note:

No antiviral drugs or vaccines are available to curtail this infection to date. However, there are reports of beneficial effects of hydroxychloroquine. But, they remain anecdotal, and the risk of dangerous adverse effects makes HCQ a risky choice for prophylaxis.

Conclusion

What doesn't kill you only makes you stronger. With every emerging virus, humanity evolves and grows, and so does healthcare. Necessity is the mother of invention, and it is also the precursor for change. The hurdles that humanity has faced so far have been overcome. With it, we have blossomed into a better and more advanced society.

Fighting the coronavirus is a way for humanity to realize the damage that can be caused by the advancement of science which ironically, is also the solution for the problem it causes!

Prevention is always better (both physically and financially) better than cure. Thus, let us protect ourselves from yet another deadly infection by spreading awareness regarding the coronavirus.

Highlights from Grand Wizard Zeo:

“COVID-19 has an average R0 (basic reproduction number) of 2.2. R0 tells you how many people can get infected by one contagious person. The current R0 of COVID-19 varies from 2 - 3.

The lockdown initiated by GOI in view of the COVID-19 pandemic is a strategy to curtail the spread of the infection. The lockdown was for 21 days from the 25th March to the 14th of April 2020.”

References:

Author’s footnotes

These are testing times for humanity. Not only do you have to protect yourself, but also your near and dear.

We urge you to fight corona by staying home, staying safe, and maintaining social distancing.

Feel free to click on the references for a more in-depth reading if you so desire.

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