Possible Scenarios on Origins of COVID-19

The novel SARS-CoV-2 coronavirus that appeared in 2020, caused a large scale COVID-19 epidemic that turned into pandemic, touching all countries worldwide.

It is a new and still not identified type of disease on which scientists, doctors, experts and the pharmaceutical industry is working on for discovering a proper cure.

The first news on the origin of this virus, were on it’s base – it came from Wuhan, China and slowly via travel and human contact it spread into other continents. On 31.13.2019 Chinese authorities alerted the World Health Organization upon the outbreak of a novel strain of coronavirus which is causing severe illness – the SARS-CoV-2.

Image by Skica911 from Pixabay

COVID-19 is spreading from person to person (human-to-human transmission) via small respiratory droplets through sneezing, coughing, touch, etc. The other way, they can land on surfaces that others may come into contact with and people can get infected if  they touch their nose, mouth or eyes.

The incubation period for COVID-19 (the time between exposure to the virus and onset of symptoms) is estimated to be between 1-14 days. A person can feel that they are infected one or two days before symptoms appear. The infectious period is estimated to last for 7-12 days in moderate cases, and can go up to two weeks on average in severe cases.

According to Kristian Andersen, PhD, associate professor of immunology and microbiology at Scripps Research and his team of experts who gathered to explore this new disease, state that this virus has a natural origin and it is a product of evolution.

Yet, according to the analysis of public genome sequence data from SARS-CoV-2 and related viruses claim that there are no evidence that the virus was made in a laboratory or  engineered.

Looking back on the history and origin of this virus and other viruses in general, Coronaviruses are viruses that circulate among animals and some of them are known to infect humans. Bats are considered natural and most common hosts of these viruses, while it is common other older and known viruses to be spread from other type of wild animals.

Andersen and his team of collaborators made researches and analyses that brought them to conclusion that the most likely origins for SARS-CoV-2 followed one of two possible scenarios:

1. The virus evolved to its pathogenic state through natural selection in a non-human host and then was transmitted to humans – here researchers commented that bats are  the most common reservoir for SARS-CoV-2 because it is very similar to a bat coronavirus. But, there are not documented cases or evidence of direct bat to human transmission.

2. A non-pathogenic version of the virus has been firstly infected into an animal host and than transmitted into humans. After some period, it evolved to the current pathogenic state around the human population.

Source:

https://www.sciencedaily.com/releases/2020/03/200317175442.htm

https://www.ecdc.europa.eu/en/covid-19/questions-answers

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