Pangolin carriers coronavirus similar to Covid-19

Researchers at the Shantou University-University of Hong Kong Joint Institute of Virology in China and Guangxi Medical University recently reported in the British journal Nature that they found a coronavirus similar to COVID-19 in samples from smuggled pangolin. This similarity, however, is not enough to suggest that the pangolin is an intermediate host that is causing the current outbreak.

The researchers obtained a number of smuggled pangolin samples intercepted in recent years in Guangxi and Guangdong, China, and conducted RNA (ribonucleic acid) high-throughput sequencing and other analysis of the samples found that these pangolins carry a coronavirus with COVID-19 genome sequence similarity of 85.5 percent to 92.4 percent.

The analysis showed that the pangolin-carrying coronaviruses and COVID-19 were in the "COVID-19-related evolutionary clade" in the coronavirus evolutionary tree, and the pangolin-carrying coronaviruses belonged to two subtypes of this clade, and the similarity between the spiny protein receptor-binding domain of one subtype and COVID-19 was as high as 85.5% to 92.4%. 97.4 per cent.

The receptor-binding domain of the bristleconidial protein acts as a "hook" that hooks onto the host cell and plays a key role in the invasion of the virus into the cell.

The strain most similar to COVID-19 is the coronavirus found in bats by researchers from the Wuhan Institute of Virology, Chinese Academy of Sciences, with 96 percent genomic identity and 89.2 percent receptor-binding domain similarity.

The pangolin is the only mammal other than bats known to be infected by COVID-19-associated coronaviruses to date, and is likely to be a long-term host for such viruses, the researchers said.

The researchers note that the latest findings are not sufficient to suggest that the pangolin is an intermediate host that caused the current outbreak, but it should be considered a possible host for COVID-19. A strict ban on trading pangolin in the market would reduce the risk of future transmission of the virus to humans.

Previously, a team from Lingnan Modern Agricultural Science and Technology Guangdong Laboratory in collaboration with South China Agricultural University published a preprint of a paper saying that the pangolin-carrying coronavirus sequence they spliced from the macrogenome shares about 90 percent similarity with the COVID-19 genome sequence, suggesting that the pangolin may be an intermediate host for COVID-19. The paper has not yet been peer-reviewed.