A sense of panic has spread in Wuhan as the Chinese city of 11 million people was put on lockdown in an attempt to quarantine a deadly virus believed to have originated there.

On Thursday, authorities banned all transport links from the city, suspending buses, the subway system, ferries and shutting the airport and train stations to outgoing passengers.

Nearby Huanggang and Ezhou suspended buses, subways and ferries and shut the airport and train stations to outgoing passengers.

In Wuhan, supermarket shelves were empty and local markets sold out of produce as residents hoarded supplies and isolated themselves at home. Petrol stations were overwhelmed as drivers stocked up on fuel amid rumours that reserves had run out. Local residents said pharmacies had sold out of face masks.

Few pedestrians were on the street and families cancelled plans to get together for the lunar new year holiday. Special police forces were seen patrolling railway stations. Residents and all government workers are now required to wear face masks while in public spaces.

“When I saw the news when I woke up, I felt like I was going to go crazy. This is a little too late now. The government’s measures are not enough,” said Xiao, 26, a primary school teacher in Wuhan, who asked not to give her full name.

Some residents posted photos of their newly bought supplies of instant noodles and snacks on social media. “No more going out … so I won’t get sick,” wrote one person on Weibo, adding: “Hope Wuhan can get some support soon.”

Others said the lifts in their apartment complexes were being disinfected and that most of their friends and relatives in the city were also planning on staying in as much as possible.

A staff member checks the body temperature of a passenger after a train from Wuhan arrived at Hangzhou Railway Station in Hangzhou.
A staff member checks the body temperature of a passenger after a train from Wuhan arrived at Hangzhou Railway Station in Hangzhou. Photograph: STR/AFP via Getty Images

At least 571 people have been infected with the coronavirus, which is part of the same family of viruses that gave rise to Sars. It has now reached almost all of the country’s provinces as well as the US, Taiwan, South Korea, Thailand and Hong Kong. Vietnam and Singapore confirmed their first cases on Thursday.

Chinese authorities said on Thursday that 95 patients were in critical condition.

Guardian graphic.

Hong Kong officials announced on Thursday they would turn two holiday camps, including a former military barracks, into quarantine zones for people who may have come into contact with carriers of the Wuhan virus.

Seventeen people have died since the virus was detected in late December, all of them in Hubei province, of which Wuhan is the capital. Many of the deaths occurred in Wuhan, where a seafood market selling wild animals is the suspected source of the virus. Scientists believe it probably jumped from an animal to a human and is now transmissible from one person to another, and could mutate further.

What is the virus causing illness in Wuhan?

It is a member of the coronavirus family that has never been encountered before. Like other coronaviruses, it has come from animals, or possibly seafood. New and troubling viruses usually originate in animal hosts. Ebola and flu are examples.

What other coronaviruses have there been?

Severe acute respiratory syndrome (Sars) and Middle Eastern respiratory syndrome (Mers) are both caused by coronaviruses that came from animals.

What are the symptoms of the Wuhan coronavirus?

The virus causes pneumonia. Those who have fallen ill are reported to suffer coughs, fever and breathing difficulties. In severe cases there can be organ failure. As this is viral pneumonia, antibiotics are of no use. The antiviral drugs we have against flu will not work. If people are admitted to hospital, they may get support for their lungs and other organs as well as fluids. Recovery will depend on the strength of their immune system. Many of those who have died are known to have been already in poor health.

Is the virus being transmitted from one person to another?

Human to human transmission has been confirmed by China’s national health commission. As of 27 January, the Chinese authorities had acknowledged more than 2,700 cases and 56 deaths. In the past week, the number of confirmed infections has more than tripled and cases have been found in 13 provinces, as well as the municipalities of Beijing, Shanghai, Chongqing and Tianjin. The virus has also been confirmed outside China, in Hong Kong, Macau, Japan, Nepal, Singapore, South Korea, Taiwan, Thailand, the US, and Vietnam. There have not been any confirmed cases in the UK at present, with the more than 70 people tested for the virus all proving negative. The actual number to have contracted the virus could be far higher as people with mild symptoms may not have been detected. Modelling by WHO experts at Imperial College London suggests there could be as many as 100,000 cases, with uncertainty putting the margins between 30,000 and 200,000.

How worried are the experts?

There were fears that the coronavirus might spread more widely during the week-long lunar new year holidays, which start on 24 January, when millions of Chinese travel home to celebrate, but the festivities have largely been cancelled and Wuhan and other Chinese cities are in lockdown.

At what point should you go to the doctor if you have a cough, say?

Unless you have recently travelled to China or been in contact with someone infected with the virus, then you should treat any cough or cold symptoms as normal. The NHS advises that there is generally no need to visit a doctor for a cough unless it is persistent or you are having other symptoms such as chest pain, difficulty breathing or you feel very unwell.

Should we panic?

No. The spread of the virus outside China is worrying but not an unexpected development. It increases the likelihood that the World Health Organization will declare the outbreak to be a public health emergency of international concern on Thursday evening. The key concerns are how transmissible this new coronavirus is between people and what proportion become severely ill and end up in hospital.

Sarah Boseley Health editor and Hannah Devlin 

“It’s truly an extraordinary development. You have a city of 10 million people being shut down,” said Dali Yang, a professor of political science focusing on China at the University of Chicago. “In many ways the local leadership and the population are definitely not prepared. This is truly an emergency for them.”

On Thursday some residents raced to leave Wuhan before the de facto quarantine was put into effect at 10am, lining up at the airport and at train stations. Local authorities, announcing the emergency measure at around 2am on Thursday, said citizens would be notified later when the restrictions were lifted.

Anxiety has been exacerbated by reports that sick patients are being turned away from hospitals without enough room. “Infected people could be right beside you and you wouldn’t know. That is what is scarier,” said Xiao, who has not left home since Sunday.

Wuhan’s disease prevention and control centre released a statement on Thursday asking residents not to panic and not to stockpile. “At the present time, Wuhan’s reserves of food, medicine and other supplies are all enough,” it said.

Authorities have made an effort to update citizens regularly on the situation and state media have attempted to frame the current shutdown as a battle being waged by the people of Wuhan for the good of the country. The state-run People’s Daily posted on Weibo: “Come on Wuhan, let us win this disease prevention war together!”

A worker disinfects a railway station in Nanchang City, Jiangxi province, China.
A worker disinfects a railway station in Nanchang City, Jiangxi province, China. Photograph: Hu Guolin/EPA

But residents are wary of the information provided by their government, which in recent weeks repeatedly said the virus was not serious and was “controllable”.

“I am a bit panicked because before the government said it wasn’t serious so no one thought it was a big deal,” said Wang Ying, 26, a government worker who described going out in large crowds on New Year’s Eve, despite the virus having been detected before then.

“Then this morning, Wuhan was suddenly sealed off. I think the government’s early warnings were not enough.”

Chinese paramilitary officers wearing masks stand guard at an entrance of the closed Hankou Railway Station after the city was locked down following the outbreak of a new coronavirus in Wuhan.
Chinese paramilitary officers wearing masks stand guard at an entrance of the closed Hankou Railway Station after the city was locked down following the outbreak of a new coronavirus in Wuhan. Photograph: China Daily/Reuters

Others criticised local authorities, who held a lunar new year banquet for 40,000 people days before authorities announced that the virus could be transmitted between humans.

“It’s been a month since the first case was discovered and only now do they think of closing the city? This Wuhan emergency response is a little slow, right?” another Weibo user wrote.

As reports circulated online that food prices had gone up in Wuhan, there were calls for government intervention. One person said: “The government needs to address this. If things become too expensive, people will definitely panic and when people feel unsafe, terrible things happen. Right now people are fighting over supplies, soon they may just be fighting.”

Additional reporting by Lillian Yang