In: Biology
Is there evidence that shows the COVID-19 originated in a bat? How would you go about generating data to make sure from a biological standpoint?
Yes there are some evidences that show covid-19 emerged in a bat.the etiological agent for the disease was a betacoronavirus belonging to a new clade in subgenus Sarbecovirus in the Orthocoronavirinae subfamily.Phylogenetic studies of the new virus showed it shared about 79% nucleotide homology with SARS-CoV, as well as to two SARS-like coronaviruses isolated from Chinese horseshoe bats (Rhinolophus sinicus) in Zhoushan, with which it shared 89% nucleotide homology and to a third SARS-like coronavirus from an Intermediate horseshoe bat (R. affinis), with which it shared 96% nucleotide homology.
The virus was detected from the areas of Wuhan market in China. The virus was amplified in the market and hence it does note tell about the origin.Angiotensin-converting enzyme II (ACE2) is known to be the cell receptor for SARS-CoV, and also for some SARS-like bat coronaviruses. Sequence studies found that the receptor-binding domain of the SARS-CoV-2 virus was sufficiently similar to that of SARS-CoV to indicate it could efficiently use the human ACE2 receptor for entry to human cells. Infectivity experiments were undertaken with HeLa cells expressing or not expressing ACE2 from humans, bats, civets, pigs and mice, and the results confirmed that SARS-CoV-2 virus was able to use entry receptors on all ACE2-expressing cells other than mice5. Molecular modelling has indicated that the binding affinity of SARS-CoV-2 to ACE-2 may be even higher than that of SARS-CoV and it may therefore be more efficient at infecting human cells. Evidence from the sequence analyses clearly indicates that the reservoir host of the virus was a bat, probably a Chinese or Intermediate horseshoe bat, and it is probable that, like SARS-CoV, an intermediate host was the source of the outbreak. To ensure that future cross-species transmission events of this new virus don’t occur again in the future, it is important to identify the reservoir and intermediate wildlife hosts. The closest known wildlife sequence to SARS-CoV-2 remains the sequence from the virus isolated from an Intermediate horseshoe bat, but there were significant differences in the receptor-binding domain between the two viruses. Malayan pangolins (Manis javanica) have been how been found out to be the intermediate hosts.