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It started in a live animal market late last year in the sprawling Chinese city of Wuhan. Now a mysterious virus previously unknown to science has killed at least 300 people, left more than 14,500 sick and led to the lockdown of 50 million people in central China.

The rapid spread of the flu-like illness has put the world on high alert. Cases have emerged in more than 20 countries, already surpassing the number formally diagnosed during the deadly SARS outbreak of 2002 and 2003 and casting a pall over China’s biggest annual holiday, Lunar New Year.

On January 30 the World Health Organisation declared the emergence of the virus a global health emergency but so far experts note it does not appear as deadly as similar outbreaks.

In China, celebrations – and cities – have ground to a halt as part of an unprecedented government effort to contain millions of people travelling for the holiday. But, despite the lockdown, the US, France and Japan have already flown hundreds of their citizens back home from the epicentre of the outbreak. The Australian government, under pressure to free its own citizens, including more than 100 children, is now in the midst of an extraordinary plan to airlift evacuees to the Christmas Island detention centre for quarantine. On February 1, Australia followed Italy and the US in barring entry to all but its own citizens and their families who are travelling from mainland China.

While most cases are still in China, the virus has been confirmed elsewhere in Asia including Thailand, Singapore and Japan as well as further afield in Europe, the Middle East and North America. Australia has now 12 confirmed cases across NSW, Victoria, Queensland and South Australia, as the race picks up to develop a vaccine for the virus authorities say is already mutating.

So what is a coronavirus, how does it spread and is this actually the world’s next SARS?

China Eastern Airlines cabin crew at Brisbane International Airport.

China Eastern Airlines cabin crew at Brisbane International Airport.Credit:AAP


What is a coronavirus?

Coronaviruses are a broad family of viruses that cause respiratory illnesses. They are mostly found in animals – only six have previously been identified in humans including SARS-CoV, which led to the SARS (Severe Acute Respiratory Syndrome) outbreak almost 20 years ago.

This new virus brings that tally to seven. Known as 2019-nCov (for novel coronavirus), the strain emerged in December, and has been traced back to a live animal market in the capital of China’s central Hubei province, Wuhan. The market has since been closed and quarantined. People often catch viruses causing colds and flu – including some known coronaviruses. But when a new strain jumps to humans, often through the handling and slaughter of wildlife, it can be dangerous as there is little natural immunity to fight it off.



What are the symptoms and how serious is it?

It appears to start with a fever, a cough or shortness of breath and can lead to more serious pneumonia-like complications.

Experts say medical authorities have unlocked the genetic code of the virus – which is about 75 per cent similar to the SARS strain – in “record time”, thanks to cooperation from a Chinese government eager to avoid a repeat of the SARS crisis that saw it accused of a cover-up.


The next few weeks will be critical to the world’s understanding of the virus, says infectious disease specialist Sanjaya Senanayake. While a lot is still unknown, Chinese authorities have warned the new strain is already mutating as it enters a “critical stage” and its spread picks up speed.

The country’s health minister, Ma Xiaowei, told reporters on January 26 that, unlike the SARS strain, this new virus is infectious during its one to 14 day incubation period – before a person shows symptoms. While experts had at first been sceptical of this “unusual” finding, Australia’s chief medical officer Brendan Murphy said the case of a Chinese national without symptoms who travelled to Germany for a conference and infected four people was convincing evidence.

The total number of cases is also expected to be much higher than official numbers so far – in the depths of China’s winter, many people with milder cases might dismiss them for a common cold, associate professor Senanayake says.

Its spread has already well surpassed the 8000-odd people officially diagnosed with SARS. Still, experts have been cautious so far when assessing the new virus’s danger, noting at present its cases have been milder overall – and the death toll lower – than both SARS and the other deadly coronavirus MERS (Middle East Respiratory Syndrome). The WHO estimates only about 20 per cent of people infected so far have suffered serious complications and says the death rate is falling as new cases are discovered.

By February, the first death recorded outside of China was confirmed in the Philippines but  340 people had recovered from the infection world-wide, including two of the four people diagnosed in NSW.

Meanwhile, an Australian lab has become the first place outside China to successfully replicate the virus – a breakthrough that could now help the CSIRO begin testing vaccines within six weeks.


The Coronavirus seen under an electron miscroscope.

The Coronavirus seen under an electron miscroscope.Credit:AFP

How is it spread?

Coronaviruses are commonly carried by bats and then passed on to humans through mammals sold at live animal markets. Previously, Chinese authorities had claimed it could only be passed from animal to humans. But on January 20, they revealed that at least two people infected had never set foot in Wuhan during the outbreak. Zhong Nanshan, a top Chinese expert investigating the virus, told state media the people had caught the virus from family members. In one case, one patient was believed to have infected 14 medical workers. Zhong warned it was now certainly a “human-to-human transmission phenomenon” and such cases of human spread have since been recorded in other countries including Japan, Germany, Canada and Vietnam.


The virus has hit at “the worst possible time” for China, Senanayake says, amid Lunar New Year celebrations.Professor James McCaw at the University of Melbourne is part of a working group urgently convened by the WHO to try to model the spread of the virus. So far their work shows each infected person tends to infect three others. That makes it more infectious than the flu but slightly less infectious than SARS and much less infectious than measles, where one person is likely to infect up to 20 people.

How can you catch it?

Senanayake says he expects the virus will spread in a similar fashion to SARS –people will catch it the way they catch a cold, from close contact with infected people, animals or contaminated surfaces. NSW Health advises the virus can jump from person to person within at least 15 minutes of face-to-face conversation, or at least two hours in an enclosed space together.


A spokeswoman said that when new confirmed cases of the virus emerged following air travel,  NSW Health contacted passengers who travelled up to two rows in front, two behind or in the same row as a person at the time they were infectious, as that was considered close contact. Experts say the virus will not survive long outside the body, meaning it is near impossible to catch from receiving a parcel or passing someone in the street.

Australian authorities are so far balancing caution with calls for calm, advising those who have recently travelled to central China or have come into close contact with a confirmed case of the new virus to self-isolate for 14 days.

Given symptoms mirror the common cold and flu, there have already been many false alarms. But those concerned they have the virus should call ahead before visiting their GP and wear a face mask. Some jurisdiction like NSW are even waiving fees for medical treatment. The WHO says the key to minimising the outbreak is to identify cases early and contain them. For the general public that means, frequent washing of hands and it can include covering the nose and mouth to prevent transmission of airborne droplets, though catching the virus in public spaces is considered less likely.

“With SARS, there wasn’t one group of people who caught it but how people reacted [to it] did depend on their health,” Senanayake says. “I expect this will be similar.”

Antibiotics do not work on the virus as it is not caused by a bacteria. As with most respiratory illnesses, it seems those most at risk are the elderly and people with underlying conditions.

Government workers take the temperature of passengers as they exit a railway station in Fuyang in central China's Anhui Province.

Government workers take the temperature of passengers as they exit a railway station in Fuyang in central China’s Anhui Province.Credit:AP


Is this another SARS?

Hanging over the emergency is the shadow of SARS – which also spread from a live animal market in China and went on to kill nearly 800 people globally. That outbreak was eventually traced back to a colony of bats and was believed to have been passed onto humans via the Himalayan palm civet, an ancient species of mammal eaten as a delicacy in China.

Authorities suspect the new virus is also linked to the illegal wildlife trade, sparking renewed calls for tougher regulation after a push to rein in wild animal markets in the wake of SARS failed. Wild and often poached animals packed together and then butchered in Chinese markets can be incubators for viruses to evolve and jump the species barrier to humans.

As it steps up containment efforts, China has banned the wildlife trade across the nation, including the shipping and sale of species. It has quarantined breeding sites and warned people against the consumption of wild animals. Conservation groups and experts are now calling on China to make the ban on wildlife trade permanent, warning the nation has not learnt the lesson of SARS.

On January 30, the WHO declared the outbreak a global health emergency, stressing the decision was “not a vote of no confidence in China”. Such declarations are usually made when a co-ordinated international response is needed, such as during the start of Ebola in the Congo and the emergence of Zika virus in the Americas in 2016. Earlier this month, the WHO decided not to declare an emergency but said further evidence of human to human transmission beyond China had now made the measure necessary. It will trigger recommendations to all countries such as stepping up monitoring and containment efforts and allow the WHO to query nations on their decisions, though the body has no legal authority to impose sanctions.

A Chinese woman wears a protective mask and sunglasses as she shops in Beijing on January 28.

A Chinese woman wears a protective mask and sunglasses as she shops in Beijing on January 28.Credit:Getty

So how is it being contained?

While Chinese authorities had maintained that the spread was still “preventable and controllable”, on January 22 they began to clamp down on the movement of people across the country. Flights, trains and buses have been shut down out of Wuhan and other cities leaving people largely indoors, wearing masks to venture out into what have been called “ghost towns”. Medical and food supplies are being rushed in as officials scramble to build make-shift hospitals to contain victims.

Large-scale quarantines are rare around the world, even during deadly epidemics, and memories of the secrecy wielded by the Chinese government during the SARS crisis is now fuelling some distrust. For months, China parked SARS patients in hotels and drove them around in ambulances to conceal the true number of cases and avoid WHO experts.


This time around, China’s leader President Xi Jinping has told officials to promptly pass on updates, put lives first and work with international agencies. “Anyone who deliberately delays and hides the reporting of [virus] cases out of his or her own self-interest will be nailed on the pillar of shame for eternity,” a notice from Beijing’s Central Political and Legal Affairs Commission reads.

This week, as confirmed cases skyrocketed, state media quoted Xi as saying he was still confident China would win the battle against the virus he called “a devil”. Other Chinese officials said that while the virus had spread to at least 18 countries, those patients accounted for less than 1 per cent of cases, suggesting containment measures were mostly working.

Countries are screening for people with symptoms at airports, as many airlines, including Qantas, shutter flights from China. Italy has banned all air traffic from the nation and on January 29, the Trump administration said it would bar entry to foreign nationals who had recently travelled to China as it declared a public health emergency over the outbreak.

Due to the “escalating threat of the virus” Australia has since beefed up its own border measures and followed suit with a ban on travellers from China, though citizens, permanent residents and their dependents or spouses will be accepted in and urged to self-isolate. New Zealand and South Korea have also followed suit.

On January 23, the last flight from Wuhan to Australia arrived in Sydney as the Chinese city went into lockdown. Australian health authorities have stockpiled 10 million masks and are now tracing people who shared flights with infected patients.

Since the terror of SARS and then MERS in 2012, Senanayake says screening and quarantine methods have improved around the world.

“Still, we are vulnerable to a superbug or virus at any time.”

On social media, people are posting prevention advice such as wearing masks and washing hands. Many cancelled their travel plans for Lunar New Year. But misinformation and even xenophobia is also spreading fast as panic picks up.

Many countries including Australia and the US are urging citizens not to travel to China – a move the Chinese Foreign Ministry has slammed as “truly mean” given the WHO’s praise for its containment efforts so far. Inside Wuhan, some doctors have spoken of being ordered to keep early cases quiet.

After months of anti-Beijing protests, tensions in Hong Kong are again threatening to boil over as leader Carrie Lam rejects calls from medical unions to close the border with mainland China to contain the virus.

How big is the risk to Australia?

 While experts acknowledge Australia is vulnerable to the outbreak – given its high influx of travellers from China – authorities have stressed it has good measures in place to deal with the virus.

“There is no reason for alarm in the general community,” said Victorian state health minister, Jenny Mikakos, following the first revelation of an Australian case – a man in Melbourne with pneumonia on January 25.


Four days later, Prime Minister Scott Morrison announced a plan to evacuate the 600-odd Australians from central China to Christmas Island, where they will be held for a 14-day quarantine in the near-empty detention centre. The first flight is expected to take off as early as Monday but the Australian government is still in talks with Beijing. Some people on Christmas Island have hit back ata lack of consultation on the plan, voicing concern about becoming a “leper colony”.

Hundreds of US citizens as well as Japenese and European nationals have already been airlifted out of the city and placed under temporary quarantines on home soil as New Zealand and Russia ready their own evacuation plans.

With Dana McCauley, Rachel Clun, Eryk Bagshaw, Liam Mannix and agencies

Sherryn Groch is the explainer reporter for The Age and The Sydney Morning Herald.

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