AN outbreak of coronavirus has so far killed 41 people and infected more than 1,200, officials said.

It comes as experts warn that Britain is on the brink of an epidemic - with more than 30 people tested for the killer illness.

After emerging in the city of Wuhan, the deadly coronavirus has continued its relentless global march, with the number of nations affected almost doubling overnight.

Confirmed cases have skyrocketed to more than 1,200 in China alone, officials said.

Among the dead is a doctor at Hubei Xinhua Hospital, reports China Global Television Network.

Liang Wudong, 62, had been at the front line of the coronavirus outbreak in Wuhan city.

Vietnam, Singapore, Saudi Arabia and Hong Kong all now have confirmed cases — alongside the US, China, Japan, South Korea, Taiwan and Thailand.

And last night France confirmed three cases and Australia one - all patients who had returned from Wuhan.

The World Health Organisation has refused to declare a global public health emergency, saying it was “too early”.

However, officials admitted the committee was split almost 50-50.

Lockdown

Fourteen major Chinese cities are in lockdown with 41million people in quarantine, with evidence of human to human transmission.

Officials have restricted travel in virus epicentre Wuhan, which is home to 11million, as well as neighbouring Huanggang, Ezhou and Lichuan.

Hospitals warned they could not cope with the number of patients turning up with symptoms.

Preliminary research suggested the coronavirus was passed on to humans from snakes at Wuhan’s seafood market.

Michael Ryan, head of WHO’s emergencies programme, said almost three-quarters of confirmed cases were in people aged over 40, with four in ten having underlying health conditions.

Experts have warned it may prove as deadly as the Spanish flu, which claimed 50million lives.

There are fears that it could accelerate further with millions travelling Chinese New Year celebrations tomorrow.

Authorities today said they would take stricter and more targeted measure to curb the spread of the virus.

Public transport has been suspended in 10 cities, shutting temples and even closing the Forbidden City and part of the Great Wall.

The risks also persuaded Shanghai Disneyland theme park to close from Saturday until further notice.

In Wuhan, the central Chinese city where the outbreak began last month, pharmacies were running out of supplies and hospitals were flooded with nervous resident seeking medical checks.

What is coronavirus? Coronavirus is an airborne virus, spread in a similar way to colds and the flu. The virus attacks the respiratory system, causing lung lesions. Symptoms include a runny nose, headache, cough and fever, shortness of breath, chills and body aches. It is incredibly contagious and is spread through contact with anything the virus is on as well as infected breath, coughs or sneezes. Symptoms include a runny nose, headache, cough and fever, shortness of breath, chills and body aches. In most cases, you won't know whether you have a coronavirus or a different cold-causing virus, such as rhinovirus. But if a coronavirus infection spreads to the lower respiratory tract (your windpipe and your lungs), it can cause pneumonia, especially in older people, people with heart disease or people with weakened immune systems. There is no vaccine for coronavirus. In 2003 an outbreak of a similar virus, SARS, infected more than 8,000 people in 37 countries before it was brought under control, killing 800 of those worldwide.

As of Thursday, there were 830 confirmed cases and 26 people had died, the National Health Commission said.

Most cases have been in Wuhan, where the virus is believed to have originated in a market that traded illegally in wildlife.

The city of 11 million people, and neighbouring Huanggang, a city of about 7 million, were in virtual lockdown.

So far, 14 people in the UK have been tested for coronavirus, with five given the all-clear and nine still awaiting results.

6 A Chinese hospital has released first pictures of doctors treating patients who have been struck down by a new deadly virus Credit: Wuhan Central Hospital/Weibo

6 A nurse checks a patient's body temperature next to a campaign poster alerting on the coronavirus at a hospital in Bangkok, Thailand Credit: EPA

British experts said up to 10,000 people could already be infected globally - adding that we can't rule out the possibility" there could already be a positive case in the UK.

Professor Neil Ferguson, an expert at Imperial College London, said the new strain is currently "as deadly as the Spanish flu epidemic".

The 1918 outbreak is the most severe pandemic in recent history, wiping out an estimated 50 million people across the world.

Prof Ferguson warned of "more deaths to come" as fellow experts said the outbreak has reached the threshold for an international public health emergency.

Where did coronavirus start? From bats to snakes - the theories on deadly virus' origins The killer coronavirus was spread from bats to snakes to humans, experts have claimed. An outbreak of the virus is understood to have started at an open air fish market in the Chinese city of Wuhan - which has since been put in lockdown after 25 people died and more than 600 people were infected globally. A new study published in the China Science Bulletin this week claimed that the new coronavirus shared a strain of virus found in bats. Previous deadly outbreaks of SARS and Ebola were also believed to have originated in the flying mammal. Experts had thought the new virus wasn't capable of causing an epidemic as serious as those outbreaks because its genes were different. But this latest research appeared to prove otherwise - as scientists scrabble to produce a vaccine. In a statement, the researchers said: “The Wuhan coronavirus’ natural host could be bats … but between bats and humans there may be an unknown intermediate." Meanwhile, scientists at Peking University also claim that the deadly virus was passed to humans from bats - but say it was through a mutation in snakes. The researchers said that the new strain is made up of a combination of one that affects bats and another unknown coronavirus. They believe that combined genetic material from both bats and this unknown strain picked up a protein that allows viruses bind to certain host cells - including those of humans. After analysing the genes of the strains the team found that snakes were susceptible to the most similar version of the coronavirus. It meant that they likely provided a "reservoir" for the viral strain to grow stronger and replicate. Snakes are sold at the Huanan Seafood Market in central Wuhan and may have jumped to other animals before passing to humans, they claim. But a senior researcher at the Wuhan Institute of Virology, who asked not to be named, said the findings should be treated with caution. He told the South China Morning Post: “It is based on calculation by a computer model. “Whether it will match what happens in real life is inconclusive. “The binding protein is important, but it is just one of the many things under investigation. There may be other proteins involved.” The expert believes that the new strain was an RNA virus, meaning that its mutation speed was 100 times faster than that of a DNA virus such as smallpox.

The previously unknown virus, which has no cure and can spread through respiratory transmission, has created alarm because there are a number of unknowns.

Emerging data suggests that the killer virus was born out of a single case which was able to ignite a chain of other infections.

The World Health Organisation reported on Thursday that there have been at least four generations of spread of the new strain, called 2019-nCoV.

That means that a person who contracted the virus from a non-human source - believed to be an animal at a seafood market in Wuhan - has infected a person, who infected another person, who then infected another person.

It's unclear whether transmission fazed out at that point, or whether further generations of cases from those chains are still to come.

6 Officials last night stepped up checks at Heathrow as the death toll doubled in a day to 17 Credit: Ian Whittaker.

6 Health officials watch travellers on a thermographic monitor at the Kuala Lumpur International Airport in Malaysia Credit: AP:Associated Press

6 Chinese people wear masks in the street of the capital Beijing Credit: EPA

Know the signs

The virus is transmitted between people in droplets from coughing and sneezing and touching or shaking hands.

One of the best ways to protect yourself from catching 2019-nCoV is to be aware of the symptoms, which include:

Runny nose

Cough

Sore throat

High temperature

Most victims of the virus die from complications including pneumonia and swelling in the lungs.

It also causes swelling in the respiratory system, which can make it hard for the lungs to pass oxygen into the bloodstream - leading to organ failure and death.

Severe pneumonia can kill people by causing them to "drown" in the fluid flooding their lungs.

Currently there is no vaccine to protect people against the virus, but researchers are looking to develop one.

However, they say it could be at least a year before it's made available.

Animal origins

The new strain of coronavirus is believed to have originated at a seafood market in the eastern Chinese city of Wuhan.

The Huanan Seafood market, which sold live koalas, snakes, rats and wolf pup to locals to eat, has since been shut down while an investigation is carried out.

6

Those most at risk are understood to be those who worked or visited the market - or has come into contact with anyone who has.

However, as the incubation period ranges from five days to two weeks, people may have unknowingly picked up the virus and subsequently travelled.

That's what makes the risk higher for those outside of Wuhan, experts say.

Scientists in China yesterday claimed that the deadly strain shares a common ancestor with a virus found only in fruit bats.

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Since then footage and images have been circulated purporting to show people eating the Chinese delicacy.

Bat soup is reported to be an unusual but popular dish particularly in Wuhan, where the virus is understood to have originated at an open air fish market.

Meanwhile, scientists at Peking University also claim that the deadly virus was passed to humans from bats - via snakes.