
The deadly new coronavirus spreading across Asia is far more contagious than previously feared and can be spread third-hand via a simple cough or sneeze, medics have today confirmed.

Eighteen people with the virus are now confirmed to have died and more than 600 have been infected in at least 10 countries. But experts predict the true number of people with the disease could be as many as 10,000 as they warn it may kill as many as two in 100 cases.

Nine towns and cities in China are now in lockdown while officials battle to stop the spread of the deadly new coronavirus. Major Chinese New Year events in Beijing have been cancelled, authorities in Ezhou have shut down train stations, and Huanggang has announced it will suspend public buses and trains.

The development comes as Wuhan – the city at the centre of the outbreak – remains in lockdown, with all flights in and outbound cancelled, residents banned from leaving and scenes of chaos as desperate families fight for food supplies.

Chinese officials are disinfecting whole streets and parks with clouds of gas and chilling footage has emerged of roadside quarantine tents, hastily erected to isolate suspected cases. One resident told the BBC the atmosphere in the city felt like 'the end of the world'. Concerned medics were seen wheeling a suspected patient out of the airport in Fuzhou in south-eastern China in an elaborate see-through quarantine pod.

Singapore and Vietnam have today announced they have recorded cases of the infection.

In Singapore, a 66-year-old man who had flown from Wuhan with his family on Monday is recovering in hospital. A 37-year-old companion is also in hospital under observation but has not been diagnosed.

In Vietnam, a Chinese father a son are in hospital in Ho Chi Minh City after flying there from Wuhan and becoming ill. They are in 'good condition', according to Vietnamese authorities.

An Indian member of government had tweeted that an Indian nurse was being treated in Saudi Arabia but that has since turned out to be inaccurate – she instead had a similar virus called MERS.

This means the illness has now spread to nine countries, including the US, and European health officials fear the never-before-seen virus will reach the continent where the UK and other nations are already on high alert.

It was revealed today that an American man infected with the deadly virus – which Chinese officials have warned will mutate and become deadlier – came into close contact with at least 16 people before he was put in isolation.

The World Health Organisation is facing increasing pressure to declare the crisis a public health emergency, like it has done for Ebola and Zika in the past. Health chiefs will meet again later today to make a final verdict.

Images have emerged showing an airline passenger with suspected coronavirus being wheeled out of an airport in a quarantine box

In one video which emerged from Wuhan today, a man can be seen 'disinfecting' eerily quiet streets of Wuhan, with billowing fumes filling the air outside an apartment block

Passengers at Rome's Fiumicino Airport Authority are scanned by thermal imaging for body temperature as they go through health measures and procedures against deadly SARS-like virus

Doctors at the Central Hospital of Wuhan attend to a patient with coronavirus. It is unclear when this picture was taken

A pictured captured today shows healthcare workers fitted with face masks helping a mother and child in Hong Kong

More than 600 people have now been infected in China and Singapore, Vietnam and Saudi Arabia were today confirmed to have cases

Experts say the difficulty of containing the coronavirus is that so many patients have mild, cold-like symptoms and don't realise they have the infection – but it can quickly turn deadly

Another clip reportedly shows an airline passenger with suspected SARS-like being wheeled out of an airport in a quarantine box

Quarantine tents appear to have been set-up on the outskirts to isolate anyone showing symptoms in a pop-up medical area

A US Border and Protection cruiser was spotted along with unmarked vehicles, and two fire trucks today at the Atlanta Hartsfield Airport

Coronavirus: What we know so far What is this virus? The virus has been identified as a new type of coronavirus. Coronaviruses are a large family of pathogens, most of which cause mild respiratory infections such as the common cold. But coronaviruses can also be deadly. SARS, or severe acute respiratory syndrome, is caused by a coronavirus and killed hundreds of people in China and Hong Kong in the early 2000s. Can it kill? Yes. Seventeen people have so far died after testing positive for the virus. What are the symptoms? Its symptoms are typically a fever, cough and trouble breathing, but some patients have developed pneumonia, a potentially life-threatening infection that causes inflammation of the small air sacs in the lungs. People carrying the novel coronavirus may only have mild symptoms, such as a sore throat. They may assume they have a common cold and not seek medical attention, experts fear. How is it detected? The virus's genetic sequencing was released by scientists in China to the rest of the world to enable other countries to quickly diagnose potential new cases. This helps other countries respond quickly to disease outbreaks. To contain the virus, airports are detecting infected people with temperature checks. But as with every virus, it has an incubation period, meaning detection is not always possible because symptoms have not appeared yet. How did it start and spread? The first cases identified were among people connected to the Huanan Seafood Wholesale Market in Wuhan. Cases have since been identified elsewhere which could have been spread through human-to-human transmission. What are countries doing to prevent the spread? Countries in Asia have stepped up airport surveillance. They include Japan, South Korea, Thailand, Hong Kong, Indonesia, Malaysia and Philippines. Australia and the US are also screening patients for a high temperature, and the UK announced it will screen passengers returning from Wuhan. Is it similar to anything we've ever seen before? Experts have compared it to the 2003 outbreak of severe acute respiratory syndrome (SARS). The epidemic started in southern China and killed more than 700 people in mainland China, Hong Kong and elsewhere Advertisement

In other developments announced today:

Cases have now been reported in 25 provinces in China, with 608 patients now infected across the world (as at 17.55GMT on January 23)

Patients suspected to have the infection are being tested in Colombia, Brazil, Mexico and Canada

Technology giant Huawei has postponed its annual developer conference in China by more than a month following the outbreak of coronavirus

Lunar New Year celebrations planned for Beijing this weekend have been cancelled over fears large gatherings may spread the virus

Singapore became the eighth country to confirm it has a patient infected with the coronavirus

Vietnam became the ninth country to confirm cases – a Chinese father and son are 'in good condition' in a hospital in Ho Chi Minh City

US authorities said at least 16 people are monitored in Washington State after coming into contact with a man there who is infected

Social media has shown chaotic scenes in Wuhan, the London-sized Chinese city at the centre of the outbreak, as it comes to the end of its first day in lockdown

Wuhan's Health Commission said the city is 'witnessing a fast growing trend of fever patients' and hospitals are facing bed shortages

Dr David Heymann, an infectious disease expert at the London School of Hygiene and Tropical Medicine, said today: 'We are now seeing second and third generation spread,' CNN reported.

Third generation spread means people are catching it from others who also caught it from a person, not the original animal source.

Dr Heymann added there is growing evidence that coughs or sneezes even close to someone could infect them, but there is no proof the virus is airborne.

No cases of coronavirus have been confirmed yet in the UK but medics at London Heathrow last night screened passengers landing from Wuhan.

And two people who travelled back from China recently are sick at a hospital in Scotland, but their condition is not known.

Health Secretary Matt Hancock said this morning that there is an 'increased likelihood' of there being a case in the UK but that the NHS is 'ready to respond appropriately'.

In the US, authorities in Washington state are monitoring at least 16 people who they say had close contact with a man there who is recovering from coronavirus after catching it in China.

President Donald Trump insisted earlier this week that the country wasn't concerned about the outbreak and added: 'We have it totally under control. We do have a plan, and we think it's going to be handled very well.'

In China, the government is being forced to take more drastic measures and nine towns and cities home to more than 20million people are now effectively in quarantine.

Officials yesterday banned Wuhan's 11million residents from travelling and ordered them to wear face masks in public to control the spread of the SARS-like infection.

Today it was announced that nearby cities of Ezhou and Huanggang – home to some one million and seven million, respectively, are taking similar steps.

Clips posted on Twitter claim to show the impact the unprecedented decision has had in Wuhan, with deserted streets reminiscent of the disaster film 28 Days Later.

Traffic has piled up on the city's major roads, which have been blocked by police vans enforcing travel bans.

In one video an eerily quiet street is seen being 'disinfected', with billowing fumes filling the air, while another shows huge 'quarantine tents' lining a neighbourhood.

Another clip reportedly shows an airline passenger being wheeled out of an airport in a quarantine box, amid suspicions he has the coronavirus.

Wearing a protective suit, a mask and gloves, the man allegedly showed symptoms during screening and was isolated from other travellers.

Social media users complained that shops have bumped up the price of fresh produce and shoppers have been seen physically fighting a crowded supermarket.

China and other countries around the world have stepped up their defences against a virus which has already killed more than a dozen people.

Officials say at least 593 cases of coronavirus have been confirmed, most of which (444 to date) are in China's Hubei province.

But other countries have been infected, too – the US, Thailand, Japan, South Korea and Taiwan have confirmed cases, and suspected infections have cropped up in Mexico, Colombia and Canada.

The virus, which goes by the name of nCoV2019, emerged in Wuhan in December from a food market, and spread to other countries by travellers.

Wuhan has been put in lockdown ahead of the upcoming Lunar New Year holiday, when thousands of people were expected to travel.

Chinese state media said Wuhan had its train stations and airport closed, while ferries and long-distance buses have also been stopped.

Twitter footage posted by @mxmbt2 shows traffic building up on a main highway.

He wrote: '[They] are not letting us leave Wuhan. The [highway] out of the city is blocked and we cannot leave. The [highway] to Xiaogan has been blocked. [The traffic] is jammed.'

Another video posted by @Dystopia992 shows police vans stopping cars from passing, causing gridlock traffic late at night.

Police, SWAT teams and paramilitary troops can be seen guarding the city's train station, where metal barriers are blocking the entrances.

Most people are protecting themselves with face masks after local authorities demanded people do so in public places to stop the illness spreading.

One Twitter user, the BBC reported, said the threat of food shortages and disinfectant in the street made it feel like 'the end of the world'.

Dr Martin Cetron, director for the Division of Global Migration and Quarantine at the US's Centers for Disease Control, described the US plan to control the spread of coronavirus following a media briefing confirming the first American case on Tuesday.

Given how quickly the virus has spread, Dr Cetron said the CDC has instructed the Department of Homeland Security and the Transportation Department to redirect anyone who tries to get from Wuhan to the US without going through any of those five airports.

At least three major Chinese cities home to a combined approximately 20million people are in lockdown as officials scramble to contain the virus

India's Minister of State for External Affairs, Vellamvelly Muraleedharan, said on Twitter that an Indian nurse working in Saudi Arabia had been diagnosed with the infection — this later turned out not to be true

Shoppers are pictured in a supermarket in Wuhan, where people are complaining that food prices have risen and videos showed people scrapping over groceries (Picture taken today, January 23)

Medical workers in Hong Kong are dressed in protective gear which they have to wear while dealing with suspected coronavirus patients (Pictured today, January 23)

People covering their mouths with masks are pictured having their temperatures checked at Hangzhou railway station in the east of China today, January 23

A screen shows the body temperatures of arriving passengers at Hong Kong International Airport, pictured today

Airline passengers queue today, January 23, at an airport in Hong Kong while wearing face masks to try and stop themselves catching the deadly virus

Another video shows overcrowded tills in a supermarket where shoppers fight over fresh vegetables

THE KILLER VIRUS MAY HAVE COME FROM BATS, SCIENTISTS SAY The killer coronavirus sweeping across the world may have come from bats, scientists have said. Researchers at the Chinese Academy of Sciences, the People's Liberation Army and Institut Pasteur of Shanghai came to the conclusion. In a statement, the team said: 'The Wuhan coronavirus' natural host could be bats… but between bats and humans there may be an unknown intermediate. Tests of the virus, which has yet to be named, have revealed it targets a protein called ACE2 – just like its cousin SARS, the South China Morning Post reported. Tracing the evolution of the virus, the team of experts found it belonged to betacoronavirus, making it structurally similar to SARS. Authorities have pointed the blame on food markets in Wuhan, the Chinese city at the centre of the outbreak that scientists are scrambling to contain. Rodents and bats among other animals are slaughtered and sold in traditional 'wet markets', which tourists flock to see the 'real' side of the country. Advertisement

Cetron described funnelling as 'a very complex process that involves reissuing tickets and rerouting passengers from all over the globe through connecting indirect flights'.

'With increasing cases, we decided to move into this full-on, 100 percent coverage strategy, which means adding additional airports and ... begin our funnelling approach and redirect all the traffic to airports that have screening so that the benefit of the alert could be more completely covered,' Cetron said.

CDC officials have also suggested the possibility of redirecting entire flights inbound from China through airports with screening checkpoints.

hen a traveler is sent for a screening in the US, they are first required to take a survey about possible symptoms, such as cough or fever, as well as whether they visited the meat or seafood markets in Wuhan that have been tied to the outbreak.

If they appear to have any symptoms associated with coronavirus, they are taken to on-site triage for further examination and a temperature check.

Two passengers flying from Shanghai on United Airlines were reportedly examined at O'Hare on Tuesday after appearing to show symptoms of coronavirus, the airline said.

It's unclear what led officials to single out the passengers, but they were both cleared and released after examination.

'We continue to follow CDC guidelines and remain in close contact with authorities in the United States and Asia to further ensure the safety of our customers and employees,' a United spokesperson told CNBC.

President Donald Trump addressed the deadly new virus during remarks at the World Economic Forum in Davos, Switzerland, early Wednesday morning.

He praised the CDC's rapid response and said the situation is being handled 'very well'.

Travellers wear face masks as a precautionary measure at Hong Kong International Airport, pictured today

Pedestrians cover their faces in Hong Kong today, January 23. At least two people have been infected in Hong Kong, which is part of the same land mass as China

Medical staff at Huazhong University of Science and Technology today attended a ceremony to form a 'assault team' in the fight against the coronavirus

WORLD HEALTH ORGANIZATION POISED TO DECLARE CORONAVIRUS AN EMERGENCY FOR ONLY SIXTH TIME EVER 2009 Swine flu epidemic In 2009 'Swine flu' was identified for the first time in Mexico and was named because it is a similar virus to one which affects pigs. The outbreak is believed to have killed as many as 575,400 people. 2014 Poliovirus resurgence Poliovirus began to resurface in countries where it had once been eradicated, and the WHO called for a widespread vaccination programme to stop it spreading. Cameroon, Pakistan and Syria were most at risk. 2014 and 2019 Ebola outbreaks Ebola killed at least 11,000 people across the world after it spread like wildfire through Guinea, Liberia and Sierra Leone in 2014, 2015 and 2016. More than 28,000 people were infected in what was the worst ever outbreak of the disease. Almost 4,000 people were struck down with the killer virus in the Democratic Republic of Congo last year. 2016 Zika outbreak Zika, a tropical disease which can cause serious birth defects if it infects pregnant women, was the subject of an outbreak in Brazil's capital, Rio de Janeiro, in 2016. Advertisement

'The CDC has been terrific, very great professionals. We're in very good shape and I think China is in very good shape also,' Trump said.

The president added in an interview with CNBC's 'Squawk Box' that he was 'not at all' concerned about the possibility of a pandemic.

'It's one person coming in from China, and we have it under control,' he said.

'We have it totally under control. We do have a plan, and we think it's going to be handled very well.'

The American man infected has not been named by CDC officials but is said to be a resident of Snahomish County, north of Seattle.

He is currently hospitalised and in 'good' condition but is being closely monitored in isolation.

The man traveled from Wuhan, but did not visit any of the markets at the epicentre of the outbreak, according to state health officials.

He arrived at Seattle-Tacoma International Airport – but not directly from Wuhan – on January 15, the day before screening was in place, and before he developed symptoms.

But he reportedly recognised his own symptoms – which typically include cough, fever and runny nose – after seeing online coverage of the virus.

The patient reached out to doctors on January 16, was tested on the 17th and his diagnosis was confirmed Monday, health officials said.

The patient is currently at Providence Regional Medical Center in Everett.

A top official at the National Institute of Health (NIH) revealed Wednesday that human trials for a vaccine targeting 2019-nCoV could begin within three months.

Anthony S Fauci, the director of NIH's National Institute of Allergy and Infectious Diseases, told Bloomberg Law that his agency is working with Cambridge, Massachusetts-based biotech company Moderna Inc to develop the vaccine.

'We're already working on it,' Fauci said. 'And hopefully in a period of about three months, we'll be able to start a phase I trial in humans.'

Medical workers at Fiumicino Airport in Rome wear protective gear as they prepare to screen passengers arriving from Wuhan today, January 23

Residents in Wuhan are pictured wearing masks to buy vegetables in the market this morning

Pictured, Wuhan residents wear masks to buy vegetables in the market today

Italian Health Ministry officials get ready to screen passengers at Rome's Fiumicino Airport for the virus

INFECTED US PATIENT 'CAME INTO CONTACT WITH 16 PEOPLE BEFORE HE WAS ISOLATED' The American man who was infected with China's new coronavirus came into close contact with at least 16 people before he was put in isolation, according to health officials. The unnamed man from Washington state, who is in his 30s, had his illness publicly confirmed on Tuesday, January 21, making him the first Westerner to be infected. Officials in the US now say he may have encountered – and therefore potentially infected – 16 or more people in America since catching the bug. He wasn't diagnosed until Monday, January 20, after returning home from China five days earlier and becoming ill later that week. Advertisement

Fauci said his agency was also working with the WHO and CDC to obtain information about helping doctors around the world identify symptoms of coronavirus.

'Obviously as is always the case when we have these outbreaks, it's a lot of collaboration and synergy between the CDC and the WHO and the NIH,' he said. 'Our job ultimately is to develop countermeasures.'

Vaccine experts at Baylor University are also reportedly working on modifying a vaccine they designed to prevent SARS to protect against the new, related coronavirus.

But the school's Dean of Tropical Medicine, which is developing the shot, Dr Peter Hotez, told DailyMail.com that it's likely years away from deployment.

'To my knowledge, trying to contain a city of 11million people is new to science,' Gauden Galea, the World Health Organisation's representative in China, told the Associated Press.

'It has not been tried before as a public health measure. We cannot at this stage say it will or it will not work.'

An Oxford University expert yesterday said the outbreak so far has been 'extraordinary'.

Dr Peter Horby said: 'We haven't seen this large-scale spread since Sars.'

Speaking about whether he thought the World Health Organization should declare it an international emergency, he added: 'There are three criteria – one, is this an extraordinary event? Two, is it spreading internationally? Three, is an international response required? In my opinion all three of these have been met.'

China and other countries around the Asia-Pacific have stepped up their defence against the virus. Pictured, a protective mask is offered to people in a car in Chongqing, China

China banned trains and planes from leaving Wuhan at the centre of a virus outbreak on January 23. Pictured, an attendant offers free protective masks to a passenger at a gas station

Paramilitary police stand guard at an entrance to the closed Hankou Railway Station in Wuhan in central China's Hubei Province

Chinese state media said Wuhan had its train stations and airport closed, while ferries and long-distance buses were also stopped. Normally this station in Wuhan is packed with passengers, but was eerily quiet on January 23

Social media users complained on social media that food vendors were exploiting the situation with huge price increases on fresh produce. Pictured, residents buy vegetables wearing masks

Chinese flight attendants wear masks to go through customers at Rome's Fiumicino Airport

'LEAVE YOUR OFFICE AND SHUT THE PATIENT IN', UK DOCTORS TOLD IN CORONAVIRUS WARNING Doctors in the UK have been told to leave the room straight away and shut their patient in if they think they might have the Chinese coronavirus. Public Health England has issued official guidance for doctors as concerns grow that the contagious illness will make its way to the UK. More than 600 people have now been infected in Asia and 18 have died. Health authorities and university experts say it is likely cases will appear in Europe and the UK. No cases have been confirmed in the UK yet, but the Government last night screened patients arriving at Heathrow from the Chinese city at the centre of the outbreak, Wuhan. At least 15 medical workers in Wuhan have become infected while treating patients with the virus. The PHE guidance, which was issued to GP practice doctors this week, reads: 'If [the Wuhan coronavirus] is considered possible when a consultation is already in progress, withdraw from the room, close the door and wash your hands thoroughly with soap and water. 'Avoid physical examination of a suspected case. The patient should remain in the room with the door closed. Belongings and waste should remain in the room. 'Advise others not to enter the room. If a clinical history still needs to be obtained or completed, do this by telephone. 'The patient should not be allowed to use communal toilet facilities. 'Instruct them to not touch anything or anyone when walking to the toilet. Instruct the patient to wash their hands thoroughly after toileting.' If the patient is critically ill, they should be put into an ambulance, PHE said. But otherwise, a hospital should be phoned ahead and warned and the patient must be told to get there without using public transport or a taxi. Advertisement

Citizens in Peking wear masks to defend against the potential spread of the coronavirus

A staff member checks a passenger's body temperature at Wangjiadun metro station in Wuhan this morning

A China Eastern Airlines aircrew member arrives at Sydney airport after landing on a plane from Wuhan today

Crew from China Eastern Airlines leave the airport wearing face masks after arriving in Sydney from Wuhan this morning

Flight crew from China Eastern Airlines leave Sydney airport wearing face masks after arriving from Wuhan this morning

Pedestrians cover their faces with sanitary masks after the first cases of coronavirus have been confirmed in Hong Kong, pictured today

Heathrow passengers arriving from coronavirus epicentre claim they were barely checked on landing Heathrow passengers arriving from the coronavirus-stricken Chinese city of Wuhan yesterday claimed they were barely checked for the killer infection. Health officials claimed flights arriving from the city home to 11million people would be subject to 'enhanced monitoring' amid fears the outbreak – which has already killed 18 people – will reach Britain. But one passenger described having a regular arrival through baggage reclaim and customs, revealing: 'It could have been a completely normal flight'. They added: 'All we were given was the mask and the check of our temperature. We were told to ring the NHS 111 if we start feeling ill and that's it.' Passengers were also given a Public Health England leaflet, advising them to contact doctors if they felt unwell. The never-before-seen virus can cause a fever. Advertisement

Experts from the WHO will meet again today to decide whether to declare an global health emergency over China's coronavirus.

A decision was expected yesterday, but Dr Tedros Adhanom, director general of the WHO, said pushed it back saying the committee needed more information.

He said: 'The decision about whether or not to declare a public health emergency of international concern is one I take extremely seriously, and one I am only prepared to make with appropriate consideration of all the evidence.'

He said there is a team in China working with local experts and officials to investigate the outbreak, and he added: 'We will have much more to say tomorrow.'

On Wednesday the Department of Health and Social Care (DHSC) said precautionary measures were being put in place at Heathrow after cases of the virus spread to other parts of the world.

But a passenger arriving in Heathrow last night was described having a regular arrival through baggage reclaim and customs, revealing: 'It could have been a completely normal flight'.

They added: 'All we were given was the mask and the check of our temperature. We were told to ring the NHS 111 if we start feeling ill and that's it.'

Passengers were also given a Public Health England leaflet, advising them to contact doctors if they felt unwell. The never-before-seen virus can cause a fever.

There are three direct flights a week from Wuhan in China to Heathrow Airport, landing at around 6pm on Monday, Wednesday and Friday.

Under the new measures, it was planned that planes would be taken to an isolated area of terminal four.

Health care workers in Hong Kong are pictured today giving first aid in an ambulance as they cover their faces with sanitary masks

Passengers wearing masks arrive at Sydney airport after landing on a plane from the Chinese city of Wuhan today

Workers manufacture protective face masks in a factory, as face mask stocks run low amid the outbreak of coronavirus, in Handan, Hebei Province, pictured today

People wearing masks board a train for the direction of Wuhan at Hongqioa train station as they head home for the Lunar New Year in Shanghai, pictured today

The captain of each flight would then tell passengers during landing to let a flight attendant know if they feel unwell, and these details would then be passed on to public health teams at the airport who would carry out further checks.

Meanwhile, the Foreign and Commonwealth Office updated its travel advice for China, with a spokesman saying: 'In light of the latest medical information, including reports of some person-to-person transmission, and the Chinese authorities' own advice, we are now advising against all but essential travel to Wuhan.

'The safety and security of British nationals is always our primary concern and we advise British nationals travelling to China to remain vigilant and check our travel advice on gov.uk.'

PHE upgraded the risk to the UK population from coronavirus from 'very low' to 'low'.

In a report published yesterday, the European Centre for Disease Prevention and Control said 'further global spread is likely'.

And ECDC added 'there is a moderate likelihood of detecting cases imported into European countries'.

WHAT DO WE KNOW ABOUT THE DEADLY CORONAVIRUS IN CHINA? It emerged today that the deadly new virus spreading across Asia is far more contagious than previously thought and someone who is infected can spread it with just a simple cough or a sneeze, scientists say. Eighteen people with the virus are now confirmed to have died and more than 600 have been infected in at least 10 countries. But experts predict the true number of people with the disease could be as many as 10,000 as they warn it may kill as many as two in 100 cases. Here's what we know so far: What is the Wuhan coronavirus? A coronavirus is a type of virus which can cause illness in animals and people. It is an RNA virus (RNA is a type of genetic material called ribonucleic acid), which means it breaks into cells inside the host of the virus and uses them to reproduce itself. This coronavirus from Wuhan is one which has never been seen before this outbreak. It is currently named 2019-nCoV, and does not have a more detailed name because so little is known about it. Dr Helena Maier, from the Pirbright Institute, said: 'Coronaviruses are a family of viruses that infect a wide range of different species including humans, cattle, pigs, chickens, dogs, cats and wild animals. 'Until this new coronavirus was identified, there were only six different coronaviruses known to infect humans. Four of these cause a mild common cold-type illness, but since 2002 there has been the emergence of two new coronaviruses that can infect humans and result in more severe disease (Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses). 'Coronaviruses are known to be able to occasionally jump from one species to another and that is what happened in the case of SARS, MERS and the new coronavirus. The animal origin of the new coronavirus is not yet known.' The first human cases were publicly reported from the Chinese city of Wuhan, where approximately 11million people live, three weeks ago after medics first started seeing cases in December. By January 8, 59 suspected cases had been reported and seven people were in critical condition. Tests were developed for the new virus and recorded cases started to surge. The first person died that week and, by January 16, two were dead and 41 cases were confirmed. The next day, scientists predicted that 1,700 people had become infected, possibly up to 4,500. Today, just one week later, there have been more than 600 confirmed cases and those same scientists estimate that some 4,000 – possibly 9,700 – were infected in Wuhan alone. There are now 10 countries with confirmed cases and 18 people have died. Where does the virus come from? Nobody knows for sure. Coronaviruses in general tend to originate in animals – the similar SARS and MERS viruses are believed to have originated in civet cats and camels, respectively. The first cases of the virus in Wuhan came from people visiting or working in a live animal market in the city, which has since been closed down for investigation. Although the market is officially a seafood market, other dead and living animals weere being sold there, including wolf cubs, salamanders, snakes, peacocks, porcupines and camel meat. Bats are a prime suspect – researchers at the Chinese Academy of Sciences said in a recent statement: 'The Wuhan coronavirus' natural host could be bats… but between bats and humans there may be an unknown intermediate.' And another scientific journal article has suggested the virus first infected snakes, which may then have transmitted it to people at the market in Wuhan. Peking University researchers analysed the genes of the coronavirus and said they most closely matched viruses which are known to affect snakes. They said: 'Results derived from our evolutionary analysis suggest for the first time that snake is the most probable wildlife animal reservoir for the 2019-nCoV,' in the Journal of Medical Virology. So far the fatalities are quite low. Why are health experts so worried about it? Experts say the international community is concerned about the virus because so little is known about it and it appears to be spreading quickly. It is similar to SARS, which infected 8,000 people and killed nearly 800 in an outbreak in Asia in 2003, in that it is a type of coronavirus which infects humans' lungs. Another reason for concern is that nobody has any immunity to the virus because they've never encountered it before. This means it may be able to cause more damage than viruses we come across often, like the flu or common cold. Speaking at a briefing yesterday, Oxford University professor, Dr Peter Horby, said: 'Novel viruses can spread much faster through the population than viruses which circulate all the time because we have no immunity to them. 'Most seasonal flu viruses have a case fatality rate of less than 1 in 1,000 people. Here we’re talking about a virus where we don’t understand fully the severity spectrum but it’s possible the case fatality rate could be as high as two per cent.' If the death rate is truly two per cent, that means two out of every 100 patients who get it will die. 'My feeling is it’s lower,' Dr Horby added. 'We're probably missing this iceberg of milder cases. But that's the current circumstance we're in. 'Two per cent case fatality rate is comparable to the Spanish Flu pandemic in 1918 so it is a significant concern globally.' How does the virus spread? Information has emerged today, Thursday, suggesting that the illness may spread between people just through coughs and sneezes, making it an extremely contagious infection. It is believed to travel in the saliva and therefore close contact, kissing and sharing cutlery or utensils are risky. Because it infects the lungs, it is also likely present in droplets people cough up which, when inhaled, can infect the next person. Originally, people were thought to be catching it from a live animal market in Wuhan city. But cases soon began to emerge in people who had never been there, which forced medics to realise it was spreading from person to person. There is now evidence that it can spread third hand – to someone from a person who caught it from another person. What does the virus do to you? What are the symptoms? Once someone has caught the virus it may take between two and 14 days for them to show any symptoms. If and when they do, typical signs include a runny nose, a cough, sore throat and a fever (high temperature). The vast majority of patients – at least 97 per cent, based on available data – will recover from these without any issues or medical help. In a small group of patients, who seem mainly to be the elderly or those with long-term illnesses, it can lead to pneumonia. Pneumonia is an infection in which the insides of the lungs swell up and fill with fluid. It makes it increasingly difficult to breathe and, if left untreated, can be fatal and suffocate people. What have genetic tests revealed about the virus? Scientists in China have recorded the genetic sequences of around 19 strains of the virus and released them to experts working around the world. This allows others to study them, develop tests and potentially look into treating the illness they cause. Examinations have revealed the coronavirus did not change much – changing is known as mutating – much during the early stages of its spread. However, the director-general of China's Centre for Disease Control and Prevention, Gao Fu, yesterday said the virus was mutating and adapting as it spread through people. This means efforts to study the virus and to potentially control it may be made extra difficult because the virus might look different every time scientists analyse it. More study may be able to reveal whether the virus first infected a small number of people then change and spread from them, or whether there were various versions of the virus coming from animals which have developed separately. How dangerous is the virus? The virus has so far killed 18 people out of a total of at least 600 officially confirmed cases – a death rate of around three per cent. This is a higher death rate than the Spanish Flu outbreak which, in 1918, went on to kill around 50million people. However, experts say the true number of patients is likely considerably higher. Imperial College London researchers estimate that there were 4,000 (up to 9,700) cases in Wuhan city alone up to January 18 – officially there have only been 444 there to date. If cases are in fact 100 times more common than the official figures, the death rate may be considerably lower. Experts say it is likely only the most seriously ill patients are seeking help and are therefore recorded – the vast majority will have only mild, cold-like symptoms. For those whose conditions do become more severe, there is a risk of developing pneumonia which can destroy the lungs and kill you. Can the virus be cured? The Wuhan coronavirus cannot currently be cured and it is proving difficult to contain. Antibiotics do not work against viruses, so they are out of the question. Antiviral drugs can, but the process of understanding a virus then developing and producing drugs to treat it would take years and huge amounts of money. No vaccine exists for the coronavirus yet and it's not likely one will be developed in time to be of any use in this outbreak, for similar reasons to the above. The National Institutes of Health in the US, and Baylor University in Waco, Texas, say they are working on a vaccine based on what they know about coronaviruses in general, using information from the SARS outbreak. But this may take a year or more to develop, according to Pharmaceutical Technology. Currently, governments and health authorities are working to contain the virus and to care for patients who are sick and stop them infecting other people. People who catch the illness are being quarantined in hospitals, where their symptoms can be treated and they will be away from the uninfected public. And airports around the world are putting in place screening measures such as having doctors on-site, taking people's temperatures to check for fevers and using thermal screening to spot those who might be ill (infection causes a raised temperature). However, it can take weeks for symptoms to appear, so there is only a small likelihood that patients will be spotted up in an airport. Is this outbreak an epidemic or a pandemic? The outbreak has not officially been confirmed as either an epidemic or a pandemic yet. This is likely because, despite the global concern, the number of people who have been confirmed to be infected is still relatively low. A pandemic is defined by the World Health Organisation as the 'worldwide spread of a new disease'. An epidemic is when a disease takes hold of a smaller community, such as a single country, region or continent. Advertisement

A family arrive Sydney airport after landing on a plane from Wuhan this morning

A China Eastern Airlines aircrew arrive at Sydney airport after landing on a plane from the Chinese city of Wuhan, pictured today

Children wearing masks arrive at Sydney airport after landing on a plane from the Chinese city of Wuhan, pictured today

A young boy wearing a facemask sits with a bag on the floor at the West Kowloon rail station in Hong Kong today

Passengers who arrived on one of the last flights from the Chinese city of Wuhan walk through a health screening station at Narita airport in Chiba prefecture, outside Tokyo

A China Eastern Airlines pilot arrives at Sydney airport after flying a plane from the Chinese city of Wuhan today

Airport personnel look at thermal scanners as they check on arriving passengers at Manila's international airport, Philippines. The government is closely monitoring arrival of passengers

A thermal scanner checks on arriving passengers at Manila's international airport, Philippines

A young boy wearing a mask rides on a roller bag at Changi Airport in Singapore