… about the origin – COVIDyearOne

What did we know about the origin of COVID-19?

(during the first year of the pandemic)

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COVID-19, the disease, first emerged in late 2019 in the city of Wuhan, located in central China. It is caused by the virus SARS-CoV-2, a member of the coronavirus family. This viral family includes pathogens responsible for the common cold as well as more severe diseases such as SARS (Severe Acute Respiratory Syndrome), which appeared in Asia in 2002 and was fully contained by 2004, and MERS (Middle East Respiratory Syndrome), which emerged in the Middle East in 2012.

SARS-CoV-2 is genetically similar to the virus that caused SARS, now referred to as SARS-CoV or SARS-CoV-1. Both viruses are believed to have originated in bats. SARS-CoV likely spread to humans through an intermediate host, the civet cat, while SARS-CoV-2 is thought to have come from horseshoe bats, possibly passing through another mammalian species.

horseshoe bat

Initially, scientists suspected that the virus spilled over to humans through live animals sold at a wet market in Wuhan. However, genomic analysis of early viral variants suggests a different scenario—rather than originating in the market, an infected individual likely introduced the virus there, leading to rapid transmission among people. In contrast, the MERS virus is known to have spread to humans through contact with camels.

COVID-19 is significantly less deadly than SARS or MERS for those who contract the disease, but it is far more contagious, which has resulted in a much higher overall death toll. Additionally, COVID-19 is notably more lethal and appears to be more transmissible than most strains of the seasonal flu.

It is interesting to note that viruses can evolve in bats without causing them to become “sick.” One possible reason is that these mammals maintain a high body temperature, which may help protect them—similar to how fever functions in humans, though it does not completely eliminate the virus.

Since mammalian tissues, such as those in the nasal cavity, share certain genetic similarities across species, multiple mammals can potentially be infected by this virus. So far, dogs, cats, tigers, lions, and mink have tested positive for COVID-19. There is strong evidence that farmed mink in the Netherlands transmitted the virus back to humans, but similar cases have not been confirmed in other mammals.

The likelihood of spillover events is increasing due to two main factors:

The rapid growth of the human population, which leads to more interactions between humans and wildlife.
Human encroachment into natural habitats, such as deforestation, which disrupts ecosystems and brings humans into closer contact with animals like bats.

Both of these factors significantly raise the chances of viruses crossing from animals to humans.

Scientists have repeatedly warned governments and the public about the high likelihood of future pandemics. In an ideal world, we would have been much better prepared for COVID-19. Perhaps if both authorities and the public had better understood why scientists were so certain that a pandemic was inevitable, greater efforts would have been made to prepare in advance.

Continue with What we knew about the structure of the SARS-CoV-2 virus.

What we knew
What we knew about the origin of COVID-19
What we knew about the structure of the SARS-CoV-2 virus
What we knew about the virus spreading in a population