Due to the rapid increase of new cases, Coronavirus Disease (COVID-19) quickly attracted global attention in 2019, and the pathogen was identified as SARS-CoV-2. As of now (May 7), according to real-time statistics released by Johns Hopkins University, there have been more than 3.85 million confirmed cases of new coronary pneumonia worldwide and 260,000 deaths. These figures are updated daily, and are expected to increase further. Although bats may be the host of SARS-CoV-2, it is unclear what the identity of any intermediate host might be to transfer to humans.
On May 7, 2020, Xiao Lihua, Shen Yongyi of South China Agricultural University and Chen Wu of Guangzhou Zoo published a research paper titled "Isolation of SARS-CoV-2-related coronavirus from Malayan pangolins" in Nature. The research was conducted from Malaya A coronavirus isolated from pangolin has 100%, 98.6%, 97.8% and 90.7% amino acid identity with SARS-CoV-2 in the E, M, N and S genes, respectively. In particular, the receptor binding domain in the pangolin-CoV S protein is actually the same as the SARS-CoV-2 receptor binding domain, with a non-critical amino acid difference.
Comparative genomic analysis showed that SARS-CoV-2 may be derived from the recombination of pangolin-CoV-like virus and bat-CoV-RaTG13-like virus. Pangolin coronavirus was detected in 17 of the 25 Malayan pangolins analyzed. Infected pangolins show clinical symptoms and histological changes, and circulating antibodies against pangolin-CoV react with the S protein of SARS-CoV-2. The isolation of coronaviruses highly associated with SARS-CoV-2 in pangolins indicates that they have the potential to serve as intermediate hosts for SARS-CoV-2. If the wildlife trade cannot be effectively controlled, the newly discovered coronavirus may pose a threat to public health.
In addition, on March 26, 2020, Guan Yi of the University of Hong Kong and Hu Yanling of Guangxi Medical University published a research paper entitled “Identifying SARS-CoV-2 related coronaviruses in Malayan pangolins” online in Nature. Several pangolin samples seized during the smuggling operation were tested, and coronavirus was found in the pangolin samples, which belonged to the two subtypes of the new coronavirus. One of the receptor binding domains was closely related to the new coronavirus. The discovery of multiple lineages of pangolin coronavirus and their similarity to SARS-CoV-2 suggests that pangolins should be considered as possible hosts for the emergence of new coronaviruses. The study re-emphasized that the trading of wild animals such as pangolins should be prohibited.
On March 19, 2020, the team of Zhang Zhigang of Yunnan University published a research paper entitled "Probable Pangolin Origin of SARS-CoV-2 Associated with the COVID-19 Outbreak" online at Current Biology. The research on the previously published Malay pangolin virus Omics data (this data was obtained from samples of pangolin lungs that could not be rescued successfully on March 24, 2019) were reassembled and comprehensively analyzed, and it was found that this batch of Malay pangolins carried SARS-CoV-2 similar coronavirus (named Is Pangolin-CoV), and its genome similarity to SARS-CoV-2 and BatCoV RaTG13 is 91.02% and 90.55%, respectively. All in all, this study shows that pangolin species are a natural reservoir of SARS-CoV-2. At the same time, the study also called for strengthening wildlife protection and management