Where did it come from?
Although the natural reservoir of the virus is believed to be bats with
a 96·2% sequence identity, as it’s reported by Shi et al.(P. Zhou et
al., 2020b), however, its intermediate host is not yet determined.
Experiment carried out by researchers from HK (Lam et al.) also
displayed 85·5% to 92·4% sequence identity with that of the
pangolin-derived coronavirus, together with some other evidence
suggesting that Malayan pangolins in southern China could be the
intermediate host.(Lam et al., 2020)
However, plenty of issues are still vague, whereas the theory itself
still is not fully proved. Some scholar points out that the result only
indicates that the virus is possibly originated from pangolins but not
firmly confirm the pangolin must be the intermediate host. Lam’s
research group also stated their confusion that the pangolin has
actually a comparatively limited population and they are entitled to be
endangered in many places and the high sequence identity between the
viruses may be explained by convergent evolution. And therefore, further
investigation on this subject is needed.
Other than pangolins, snakes and minks was suspected to be the
intermediate host for a short period of time, but after an intense
debate, all proposal was rejected.
To be short, most debate about the intermediate host of SARS-CoV-2 can
be found on website Biorxiv
(https://www.biorxiv.org/).
Discussion of which animal is the intermediate host end up with nothing,
leaving the question still in mystery. The only thing that had been
determined is the virus originates from bats.(P. Zhou et al., 2020b)