China has confirmed the new SARS-like virus that has killed three people has spread between humans.
China’s National Health Commission team said 14 healthcare workers had caught the respiratory virus while treating patients.
Two patients in southern China also caught the virus from infected family members, according to local media.
They had not visited Wuhan city, where the outbreak is centred and believed to have come from an animal source.
Huanan Wholesale Seafood Market in Wuhan city has been under investigation since January 1 as scientists scramble to determine the mode of transmission.
But there is now ‘affirmative’ evidence the pneumonia-causing virus could be passed through coughing, sneezing, or other bodily fluids.
A total of 222 across the Asia have now tested positive for the virus – a sharp increase from the 48 on January 17.
It comes ahead of Lunar New Year, which will see millions of Chinese citizens travelling abroad.
Three countries have also reported cases of the virus – Thailand, Japan and South Korea.
All four patients had visited Wuhan, home to 11million people. Some 3,300 people fly out from the city’s airport every day.
The unnamed novel virus has infected an estimated 1,700 in Wuhan, China. Authorities said the virus had spread to other cities in China. The total confirmed cases has tipped 200 and three have died. Four confirmed cases are outside China in Thailand, Japan, and South Korea
Two patients in southern China have caught the virus from infected family members, according to local media. Pictured, Chinese residents wear masks in Wuhan
Professor Zhong Nanshan, a renowned scientist at the National Health Commission, said human-to-human transmission is ‘affirmative’, in a press conference.
‘Currently, it can be said it is affirmative that there is the phenomenon of human-to-human transmission,’ he said, according to state broadcaster CCTV.
He added: ‘It has also been proved that medical workers had been infected… [They] worked around a patient carrying the new strain of coronavirus… and 14 of them in total.’
The two patients understood to have contracted the virus from their family are in Guangdong. They never visited Wuhan themselves.
Details about the healthcare workers have not yet come to light and only been discussed by Professor Nanshan.
The World Health Organization (WHO) said earlier an animal source seemed to be ‘the most likely primary source’ of the virus.
Investigations have focused on a food market in Wuhan where most of the first detected patients worked or visited.
Known as a ‘zoonotic disease’, it was believed harmful germs had spread from animals in the market to workers or visitors.
On January 14, the WHO said there was ‘limited’ human-to-human transmission of the virus, just two days before it said there was ‘no clear evidence of human to human transmission’.
China reported on January 20 the mysterious virus had spread across the country from Wuhan. Pictured, medical staff at Jinyintan hospital, Wuhan
Over the weekend, 136 fresh infections were reported in Wuhan, bringing the total number of cases China has confirmed to more than 200
The majority of patients have been traced to the Huanan Wholesale Seafood Market (pictured)
Paul Hunter, professor of health protection at the University of East Anglia, said for a virus to be problematic, it must be capable of spreading between people.
He told MailOnline: ‘If it’s going to cause problems around the world, it has got to spread from person to person. If it’s from an animal, it won’t be as important.’
The coronavirus – which has never been seen before – was first discovered in the city of Wuhan in December.
It is from the same family as two viruses that turned into global killers: SARS and MERS, both of which can be transferred between humans.
Scientists first thought that only animals transmitted SARS to humans. But it soon became apparent that SARS could spread between humans.
SARS started in southern China and killed more than 700 people in mainland China, Hong Kong and elsewhere in the early 2000s.
Similarly, it took ‘a while’ for scientists to spot that MERS could be spread between people, according to Professor Paul Kellam, department of infectious disease at Imperial College London.
‘It doesn’t mean the new virus will spread uncontrollably,’ he told MailOnline.
MERS was discovered in Saudi Arabia in September 2012 and has killed around 850 people. So far, all cases of MERS have been linked through travel to, or residence in, countries in and near the Arabian Peninsula.
Jeremy Farrar, a specialist in infectious disease epidemics and director of the Wellcome Trust global health charity, raised concerns about the number of people travelling through Wuhan.
He said: ‘Wuhan is a major hub and with travel being a huge part of the fast approaching Chinese New Year, the concern level must remain high.
‘There is more to come from this outbreak.’
He added that coughing is the ‘quickest way to spread an infection around the world’.
‘Whenever you get something new happening in humans, especially when it is spread by coughing, it is always a worry. It could get worse, it could get better – but you have to plan for it getting worse,’ Mr Farrar told MailOnline.
On January 17, there were 48 confirmed cases of the novel Chinese virus worldwide, 45 of which were in Wuhan.
The total has jumped up to 222 over two days, including four people in other countries and 20 in other areas of China.
Five new cases in Beijing and 14 in the Guangdong province have been confirmed.
Suspected cases have also cropped up in Sichuan, Yunnan, Shanghai, Guangxi and Shandong. Tests have yet to confirm the patients have the coronavirus.
Five other people have been put in isolation and tested in eastern Zhejiang province.
South Korea confirmed its first case on January 20 after a 35-year-old woman arriving at Seoul’s Incheon airport tested positive for the virus. She had been in Wuhan last week.
Last week, one case was confirmed in Japan and two in Thailand, meaning the total number of confirmed cases outside of China now sits at four.
A British tourist fighting for his life in Thailand is feared to be the first Western victim, but this has not been confirmed.
Ash Shorley, 32, is in critical condition in a hospital in Phuket after being struck down with a lung infection while visiting Koh Phi Phi island.
Mr Shorley had to be transported to hospital by a specialised seaplane because his lung had collapsed and he could not cope with high altitude travel.
Doctors revealed his symptoms were consistent with the Chinese coronavirus. He has been in hospital for nearly a month.
Three people have died from the virus, two of which were males in their 60s. Details of the third patient have not been revealed.
An analysis from Imperial College London last week estimated the number of cases in Wuhan was probably around 1,700 – but could even be as high as 4,500.
The team did not look at how the virus may be transmitted, but said ‘past experience with SARS and MERS-CoV outbreaks of similar scale suggests currently self-sustaining human-to-human transmission should not be ruled out.’