Investigation on the human coronaviruses origin (bats and pangolins): a review

A coronavirus related to SARS-CoV-2 has been isolated from Malayan pangolins illegally imported into Guangdong Province. It is not the precursor of SARS-CoV-2, but a comparison of viral genome sequences provides further evidence that the virus currently infecting humans. Bats and pangolins have been suggested as the natural reservoirs of a large variety of viruses. Some researchers have given attention to other species as the origin of coronaviruses and none have referred to bats and pangolins as the two emerging coronaviruses origin, which have caused unexpected human disease outbreaks recently. Severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV), are suggested to be originated from bats and pangolins. Numerous species of bats and pangolins in China have been observed to harbor genetically diverse SARS-like coronaviruses. Some strains are highly similar to SA RS-CoV even in the spike protein and are able to use the same receptor as SA RS-CoV for cell entry. Meanwhile, different coronaviruses phylogenetically related to M ERS-CoV have been observed in the bats and pangolins species, some might be classified as similar to coronavirus species as MERS-CoV. Coronaviruses genetically related to human coronavirus 229E and NL63 have been found in bats and pangolins, respectively. However, intermediate hosts are suggested to play an important role in the transmission and emergence of these coronaviruses from bats and pangolins to humans. 'this study further documented that bats and pangolins origin of human coronaviruses are meaningful to predict and prevent a future outbreak of the deadly pandemic.