The virus, which has killed 362 people so far, was believed to have transferred to humans from an animal, but identifying which one has been challenging.
Now, using samples from seven patients with severe pneumonia caused by the coronavirus, scientists have found striking similarities to coronavirus found in bats.
The DNA is also 79.5 per cent identical with the deadly SARS coronavirus, which suggests vaccines for the now non-existent virus may help with this epidemic.
Global cases have risen above 17,450, higher than the total recorded cases of the SARS virus that killed some 800 people in 2002 and 2003.
Although scientists stress the animal source of the recent outbreak in China is yet to be officially declared, experts have confirmed a wholesale animal market in Wuhan city is to blame.
A menagerie of live animals including koalas, rats and wolf pups were available at the Huanan Seafood Market in central Wuhan – the outbreak’s epicentre.
While most research has pointed towards bats, research at Peking University implicated snakes as the most likely ‘reservoir’ of the rapidly spreading virus.
The Huanan market was a hotspot with locals, who could choose to buy their meat ‘warm’ meaning it had been slaughtered just moment prior.
Dr Michael Skinner, reader in virology at Imperial College London, said: ‘The discovery definitely places the origin of nCoV in bats in China.
‘We still do not know whether another species served as an intermediate host to amplify the virus, and possibly even to bring it to the market, nor what species that host might have been.
‘But the high level of sequence similarity between nCoV and TG13 is not really compatible with some of the more exotic hosts that were considered earlier in the epidemic.’
Zheng-Li Shi, a virologist and researcher at the Wuhan Institute of Virology, and colleagues, analysed samples of seven people with what’s been dubbed ‘2019-nCoV’.
Six of those included were workers at the market in Wuhan, where cases were first reported in December.
The team found that full-length genome sequences – which determined the DNA of the virus – from five of the patients, were almost 100 per cent identical to each other.
They compared it with TG13, a coronavirus in bats, and found the virus sequence is 96 per cent identical at the whole-genome level to a bat coronavirus.
This evidence suggests bats are a probable source of this coronavirus, according to the publication in the journal Nature.
This jump between species is rare and makes the virus zoonotic — capable of infecting different species.
Bats are unaffected by the pathogens in their bloodstreams but people have no protection to the viruses as they are foreign to human immune systems.
And once in humans, it can then be easily passed from person-to-person through coughs or sneezes.
Zheng-Li Shi and colleagues also found the new coronavirus shared 79.5 per cent sequence identity with SARS, and it enters the body through the same route – via a cell receptor called ACE2.
This suggests there are some genetic differences between the novel coronavirus and SARS, but their structures are similar.
A test developed by the researchers was able to detect 2019-nCoV in oral swab samples. But samples taken about 10 days later did not have a positive result.
This suggests the most likely route of transmission is through the airways.
However, the authors say other routes may be possible, and more patient data is needed to investigate transmission routes.
In a separate study also published in Nature today, Yong-Zhen Zhang and colleagues at Fudan University, Shanghai, looked at a 41-year-old male market worker admitted to a hospital in Wuhan on December 26 2019.
Source: DailyMail (UK)