26^th April 2020

Survival of the fittest- Pandemic of Nobel Coronavirus (Covid19):

"Survival of the fittest" is a phrase that originated in 1868 from Darwinian evolutionary theory as a way of describing the mechanism of natural selection -a natural process that results in the survival and reproductive success of individuals or groups best adjusted to their environment and that leads to the perpetuation of genetic qualities best suited to that particular environment.

In Dec. 2019, Chinese city of Wuhan first reported an outbreak of atypical pneumonia caused by the 2019 novel coronavirus (2019-nCoV). From there, virus spread to 213 countries and as on 24^th April 2020, 2 724 809 were tested infected; 187 847 died of this; numbers of infected people and deaths are rising as so far there is no vaccine or cure from infection. Many research institutions are working to invent vaccine for virus. Many patients have survived the infection without treatment as their own immunity saved them.

The genomic data for COVID-19 show that its spike protein contains some unique adaptations. One of these adaptations provides special ability of this coronavirus to bind to a specific protein on human cells called angiotensin converting enzyme (ACE2).

Wide range of symptoms may appear 2-14 days after exposure to the virus: Fever, Cough, Shortness of breath or difficulty breathing, Chills, Repeated shaking with chills, Muscle pain, Headache, Sore throat, New loss of taste or smell.

COVID-19 is a respiratory disease. That means, for most patients, the virus will start and end with the lungs. In the early days of infection, the virus invades lung cells. Specifically, this can damage the cilia, the hair like projections that move around to keep airways clear of mucus and debris. When cells get infected, they die and shed off, adding to the debris and hindering your body's ability to keep stuff out of the lungs and trachea. The inflammation causes damage, and damage causes more inflammation, and this cycle could continue until there's no healthy tissue left. And inflammation might explain why a dry cough is one of the most common symptoms. Same goes for shortness of breath and phlegm production.

For some severe and critical cases, though, symptoms can escalate into acute respiratory distress syndrome (ARDS) that happens when fluid builds up in the lungs. Inflammation triggers a flood of immune cells that are meant to target the infection. They're usually isolated to infected areas, but sometimes the body goes overboard, which is when the immune cells start killing anything in their path, including healthy cells. ARDS is often fatal. In critical cases, it can lead to respiratory failure, requiring advanced life support. ARDS treatment includes supplemental oxygen and mechanical ventilation. The goal is to get more oxygen into the bloodstream since the lungs can't. When this treatment doesn't work, the lungs are basically too flooded to get any oxygen into your bloodstream. That's the cause of most COVID-19 deaths. And even when a patient survives this phase, they could be left with permanent lung damage. Most people who die of the disease will do so within 14 to 19 days of infection.

As of now, there is no vaccine for the virus. The best way to avoid getting sick is to avoid being exposed. COVID-19 is contagious, spreads easily from person to person through coughing and sneezing. To avoid, wash your hands often and avoid close contact with people who are sick and clean and disinfect surfaces that you use daily. COVID-19 should be taken seriously, but most cases are survivable, so stay home, stay clean.

Asymptomatic persons are those who probably have a mild form of the disease but don’t show any symptoms. These people become carriers and pose a risk to vulnerable person with low immunity.

If spread of the virus is not contained, then it can spread by community transmission which occurs when the source of the disease is untraceable and the virus is spread through a large number of people.

A very low proportion of the population has developed antibody response to Covid-19.

While people who have recovered from the infection have antibodies against the virus, some of them have very low levels of neutralising antibodies in their blood, “suggesting that cellular immunity may also be critical for recovery”.

The development of immunity to a virus through natural infection is a multi-step process that takes place over one to two weeks. The body responds to a viral infection immediately with a non-specific innate response in which macrophages, neutrophils, and dendritic cells slow the progress of the virus and may even prevent it from causing symptoms. This non-specific response is followed by an adaptive response, where the body makes antibodies called immunoglobulins that specifically bind to the virus.

The body also develops cellular immunity by making T-cells to eliminate other cells infected with the virus. This (cellular immunity) combined adaptive response may clear the virus from the body, and if the response is strong enough, may prevent progression to severe illness or reinfection by the same virus.

People capable of developing immunity against this virus are surviving and showing no symptoms, but they can spread infection.

Many countries across the world that have been forced to take the tough decision of locking down their populations at home to halt the spread of the pathogen. While crucial to break the chain of infections, these measures gravely threaten economic activity, with many likely to lose their jobs or have their pay cut as nations brace for a recessionary period. Residents in specified hot spots are not allowed to step out of their homes, with the authorities’ home-delivering essentials to their doorstep. People are advised to maintain social distancing.

This closure of economic activity or lock down cannot last long. Every production or manufacturing involves labor which is provided by human. In absence of labor, there cannot be any production or manufacturing. During lock down, people would consume the stock or inventories. Similarly, food production needs labor in sowing and harvesting; without this, people would feed on reserve or buffer of grains like wheat, rice. Crop also needs time in sowing and harvesting; in a season; without this future availability of food would be affected. When end of lock-down in not certain as cure / vaccine of virus yet not invented, Countries would have to accept loss of population at cost of economic activities till invention made in near future, say in months. If this last long, this would cause substantial loss of population and would damage supply chain of demand and supply of many necessities, would make people frustrated.

Homo sapiens is struggling for its survival. Population is divided into two, one who can resist infection and others who cannot. How would they co-exist? How long would lock-down and social distancing would continue? In this complex civilised world, social interaction and economic activities are essential and time is essence as people cannot remain locked-down for long.

“Necessity is mother of invention” said ancient Greek philosopher Plato. Professor of Psychology Barbara Fredrickson argues that HOPE comes into its own when crisis looms, opening us to new creative possibilities.

Let us hope for the best and adapt to new realities of existence on earth.