Further Evidence Indicates That Animal has Transmitted SARS-CoV-2 to Humans

The coronavirus may have originated from bats, but it is likely that another species has infected humans.


When the Covid-19 epidemic broke out in January, many researchers investigated the intermediate host for transmitting coronavirus to humans. On Feb 15, Wu Yuan Bin, head of the Department of Science and Technology for Social Development, China’s Ministry of Science and Technology, said the studies identified bats as the most likely species.

However, recently published findings suggest that pangolin may be a host for the virus from bat to human. In other words, the SARS-CoV-2 virus was present in the first bat, but through an intermediate host, pangolin was transmitted to humans.

Further evidence indicates that this animal has transmitted SARS-CoV-2 to humans
Bats may be the first carriers of SARS-CoV-2 virus, but do not infect humans directly.

What is Pushing Coronavirus From Animals to Person?

Mysterious intermediate host

In an article in Conversation , the team at the University of Michigan says they have evidence to show that pangolin is an intermediate host. The researchers agree with the general opinion that SARS-CoV-2 virus first appeared in Chinese horseshoe bats. However, the possibility of direct transmission from this bat to humans is quite low.

In 2003, the SARS virus was also transmitted from bats to an intermediate host, the mongoose, before it was transmitted to humans. Another coronavirus, MERS-CoV, caused the MERS epidemic in 2012 and also spreads from bats to camels before spreading it to humans.

It is important to identify the intermediate host, knowing which species will help to limit sales, thereby reducing the likelihood of spreading the virus. Since the end of January, a team of Chinese researchers said the snake, including the Chinese scorpion and cobra, could be the direct host of the SARS-CoV-2 virus to humans.

However, this study is suspected because there has been no evidence that coronavirus can be transmitted from cold-blooded animals such as snakes to humans.

Further evidence indicates that this animal has transmitted SARS-CoV-2 to humans
In late January, research conducted in China concluded that snakes may be the species that spread SARS-CoV-2 virus to humans.

Conclusions on snakes are based on the assumption that the codons (the trio of transcription codes, the genetic code on the information RNA) of the virus and host spread must be identical. After comparing the genetic codes of eight animals at the Wuhan Seafood Market, the team determined that snakes are the most similar genetic code to SARS-CoV-2.

However, the hypothesis of the above study has never been proven. The University of Michigan team compared the genetic code of the three coronavirus strains to about 10,000 animals, and found that the virus codon did not necessarily match the actual host.


The evidence shows that pangolin is the host

The group then went on to conduct a study on Malaysian pangolin (Manis javanica). They found that the genetic code taken from the coronavirus attached to the lung cells of this pangolin was 91% similar to SARS-CoV-2.

The protein spikes of these two viruses have only 5 distinct amino acids. Compared to the coronavirus from bat species, the protein spines of SARS-CoV-2 virus have 19 distinct amino acids. From this evidence, the team believes that pangolin is an animal most likely to spread the SARS-CoV-2 virus to humans.

Further evidence indicates that this animal has transmitted SARS-CoV-2 to humans
The coronavirus on pangolin has more similarities with SARS-CoV-2 than the bat virus.

This is not the first scientific study to conclude that the Malaysian pangolin. At the end of March, another research team at the University of Hong Kong also found a virus directly related to the SARS-CoV-2 virus in the Malaysian pangolin, seized from a wildlife transport line illegal in southern China.


“Detecting similarities of some strains of pangolin with SARS-CoV-2 virus suggests that the animal may be listed as an infectious host and need to be removed from animal markets. wild “, Dr. Tommy Lam, study author concludes in scientific report.

“Although pangolin is the most suspect species, our study concludes that we still need to consider other types of intermediate hosts. The coronavirus can be transmitted through many intermediate hosts before it is transmitted to humans. .

Several studies indicate that ferrets and cats can also be infected with SARS-CoV-2. We still don’t know if humans are likely to catch coronavirus from these animals, “a University of Michigan research team concluded.


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