Coronavirus Evolution and Possible Origins

Coronavirus Evolution

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The Coronavirus outbreak, which began in China, is rapidly evolving. With the global case toll rising steadily, borders around the world closing, face masks and disinfectants flying off of store shelves, and the global economy upended by the virus, it’s no wonder fear and questions are swirling about Covid-19.

The World Health Organization (WHO) declared the COVID-19 outbreak a pandemic on March 11 – a new disease that has spread across the world. Many countries have seen reported cases of the virus rise within their borders – and that includes the Philippines.  

The spread of the virus and the slow rollout of testing mean reported case numbers are quickly changing. Meanwhile, outbreaks have been surging in Italy, South Korea, and the United States. With the new virus continually spreading around the world, here are answers to your most burning questions.

  1. What are coronaviruses?
    Coronaviruses are a large family of viruses that cause respiratory and intestinal infections in animals and humans. The name comes from the Latin word corona (crown), and the ancient Greek word korōnè (wreath or garland), because of the spiky fringe that encircles these viruses.

    Initially, coronaviruses were not highly pathogenic to humans until the SARS outbreak in 2002-2003 in Guangdong province, China. Ten years after SARS, MERS-CoV – another highly pathogenic coronavirus – appeared in Middle Eastern countries. Only seven coronaviruses, including SARS, MERS-CoV, and now COVID-19, are known to infect humans.
  2. SARS-CoV-2 and COVID-19 – what’s the difference?
    Don’t be confused by these two terms! Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the name of the virus that causes Coronavirus Disease 2019 (COVID-19).

    Masks are a key measure to suppress transmission and save lives.
  3. Is the virus genetically manipulated or does it have a natural origin?
    There are numerous myths surrounding COVID-19. One of the most popular myths surrounding it is that it was deliberately made in a laboratory. However, recent research debunks this myth.

    According to recent findings, the SARS-CoV-2 virus that emerged in Wuhan, China last year and has since caused a large scale COVID-19 pandemic and spread to more than 192 countries is the product of natural evolution.

    Shortly after the pandemic began, Chinese scientists sequenced the genome of SARS-CoV-2. Then, they made the data available to researchers around the world. The genomic sequence data reveals that Chinese authorities swiftly detected the pandemic and that the number of COVID-19 cases have been increasing due to human-to-human transmission after a single introduction into the human population.

    The analysis of public genome sequence data from SARS-CoV-2 and other related viruses found no evidence that the virus was created in a laboratory or otherwise engineered. According to Kristian Andersen, PhD, an associate professor of immunology and microbiology at Scripps Research, “By comparing the available genome sequence data for known coronavirus strains, we can firmly determine that SARS-CoV-2 originated through natural processes.”

    Evidence for natural evolution. Scientists found that the RBD portion of the SARS-CoV-2 spike proteins had evolved to successfully target ACE2 a molecular feature on the outside of human cells. ACE2 is a receptor that is involved in blood pressure regulation. In fact, the SARS-CoV-2 spike protein was so effective at binding the human cells that scientists determined that it was the result of natural selection, not the product of genetic engineering.

    This evidence for the natural evolution of SARS-CoV-2 was supported by data on the virus’ backbone – its overall molecular structure. If someone were looking to create a new coronavirus as a pathogen, they would have constructed it from the backbone of a virus known to cause illness. However, scientists found that the SARS-CoV-2 backbone differed significantly from those of already known coronaviruses and mostly resembled related viruses found in pangolins and bats.

    These two distinct features of the SARS-CoV-2 virus – its distinct backbone and the mutations in the RBD portion of the spike protein, rules out laboratory manipulation as a potential origin for SARS-CoV
  4. Where did the SARS-CoV-2 virus originate?
    Based on genomic sequencing analysis, scientists concluded that the SARS-CoV-2 virus originated from one of two possible scenarios.

    In one scenario, the virus may have evolved to its current pathogenic state through natural selection in a non-human host, then jumped to humans. This is how previous coronavirus outbreaks have emerged – with humans contracting the virus affect direct exposure to camels (MERS-CoV) and civets (SARS). Researchers suggested bats as the most likely source for the SARS-CoV-2 virus as it is very similar to a bat coronavirus. However, there are no documented cases of direct bat-to-human transmission – this suggests that an intermediate host was probably involved between bats and humans.

    In this first scenario, both the distinct features of SARS-CoV-2’s spike protein would have evolved to its current state prior to entering humans. In this case, the current pandemic would have rapidly emerged as soon as humans were infected as the virus would have already evolved the features that make it pathogenic and able to spread from one person to another.

    In the second proposed scenario, a non-pathogenic version of the virus jumped from an animal host into humans – and then evolved to its current pathogenic state within the human population. For example, some coronaviruses from pangolins found in Africa and Asia have an RBD structure similar to that of SARS-CoV-2. A coronavirus from a pangolin could have been transmitted to a human – either directly or through an intermediary host (i.e. ferrets or civets).

    In this scenario, the other distinct spike protein feature of SARS-CoV-2, the cleavage site, may have evolved within a human host, probably through limited undetected circulation in the human population before the beginning of the pandemic. Searchers found that the SARS-CoV-2 cleavage site, appears the same as the cleavage sites of strains of bird flu that have been proven to easily transmit from one person to another. The SARS-CoV-2 virus may have evolved such an infectious cleavage site in human cells and soon started off the current pandemic, as the coronavirus would have become far more capable of spreading from one person to another.

The Bottom Line

Contrary to the myth surrounding COVID-19, the virus that causes this disease was not created in a laboratory; rather, scientists concluded that it has natural origins.

We hope that this article was able to clear up the evolution and possible origins of the new coronavirus.

Stay safe – stay indoors and wash your hands regularly!

Face Shields are a key measure to suppress transmission and save lives.

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