17 dead and 11 million people in lockdown: Everything you need to know about China's coronavirus outbreak.

The entire city of Wuhan in Central China has been placed into lockdown. Major public Lunar New Year holiday celebrations have been cancelled, transport networks — including flights, buses, ferries, trains — have been frozen, and its 11 million residents urged not to leave the city.

Wuhan is the source of an outbreak of novel coronavirus, which has so far infected more than 550 people and claimed 17 lives.

Health workers have been deployed to transport hubs across the country, measuring incoming passengers’ body temperature for any signs of fever. And with cases cropping up overseas, international health agencies are now also on high alert.

But what exactly is the virus? And should Australians be worried?

Mamamia‘s daily news podcast, The Quicky, spoke to experts to help break it down, including infectious disease specialist, Dr Sanjaya Senanayake, Professor of Medicine at Canberra’s Australian National University, and Dr Matt Killingsworth, Senior Lecturer in International Relations at the University of Tasmania.

What is coronavirus?

Coronaviruses are nothing new. They’re actually a big family of viruses that occur mostly in animals and are responsible for a number of common illnesses. However, certain strains can mutate, be transmitted to people and then spread person-to-person.

Another example of a human coronavirus was SARS (severe acute respiratory syndrome). SARS originated in China in 2002 and, over the course of several months, spread to two dozen countries, infected at least 8000 people and led to 774 deaths.

This new strain of coronavirus behind the current outbreak is being referred to as 2019-nCoV — or 2019 novel coronavirus. It’s not clear what animal was the source of the original human infection.

Listen: Worried about novel coronavirus? The Quicky covers all the details you need to know.

What are the symptoms of novel coronavirus and how is it spread?

As Prof Sanjaya Senanayake explained, it appears that those who contract 2019-nCoV start showing symptoms between 10-14 days later.

“Most of the time [2019-nCoV] will cause a respiratory illness, and that can be as mild as a common-cold-type illness to a severe pneumonia where you need to be in hospital with fever, coughing, shortness of breath,” he said.

While several people have died after contracting the virus, Prof Senanayake noted that many had pre-existing health issues, including heart disease.

“For a lot of infections, people who’ve got other illnesses tend to be more susceptible to a severe illness and a really bad outcome, and that’s just because they haven’t got as much reserve. And at this early stage that seems to be the case with this coronavirus,” he said. “Otherwise the mortality from it seems to be relatively low compared to other coronaviruses, like SARS, for instance.”

There is currently no definitive answer on how 2019-nCoV is spread between humans, but Prof Senanayake noted that similar viruses are transmitted via respiratory droplets, contact with contaminated surfaces and bodily fluids including blood, urine and faeces.

A vaccine is currently being developed, but that process is likely to take many months.

Where did the novel coronavirus outbreak start and how quickly has it spread?

The first case of novel coronavirus was detected in Wuhan over a month ago. The primary source has since been identified as a large seafood market in a central residential district. The market was shuttered on January 1 amid mounting reports of illness among customers and workers.

As of Thursday, there have been 554 confirmed cases of the infection in China. The majority of these have been in the Wuhan area, though dozens have been reported in the country’s east, including Beijing, Shanghai, and the providences of Guangdong and Zhejiang. Confirmed overseas cases of the virus include four in Thailand, and one each in Japan, South Korea, Taiwan and the US.

So far, the only confirmed fatalities from the outbreak have occurred in Wuhan. But of concern is how quickly the death toll is climbing: within the 24 hours to Thursday morning (Australian time) it jumped from six to 17.

The World Health Organisation is currently considering whether to declare the outbreak a global public health emergency. If the last-resort declaration is made, WHO would enact a coordinated international response to halt the spread of the virus.

Are Australians at risk?

So far there have been no confirmed cases of novel coronavirus in Australia. Earlier this week there were concerns that one Brisbane man may have contracted the virus but screening found no evidence of infection.

In order to minimise the risk of local cases, Australian authorities have bolstered biosecurity measures at airports, with particular focus on the three direct flights per week that come from Wuhan to Sydney. The last one to leave ahead of the Wuhan lockdown arrived on Thursday morning, and was met by Australian border security and biosecurity officials who provided passengers with information on the virus. Authorities said anyone reporting or displaying symptoms would be screened by NSW Health officers.

Australian Government Chief Medical Officer Brendan Murphy said local health authorities are “alert but not alarmed”.

“I want to reassure Australians that to date there have been no confirmed cases in Australia and the risk of transmission in Australia from this novel coronavirus remains low,” he said.

“We have well-established mechanisms to detect and respond to ill travellers, and processes in place to implement further measures if the risk increases.”

In the meantime, anyone who has recently travelled to Wuhan or the surrounding region and finds themselves sick is urged to contact their doctor A.S.A.P. and state where they’ve been, and limit contact with others.

Wait, doesn’t China have a history of covering up the seriousness of viral outbreaks?

It does. The authoritarian Chinese government attempted to mask the outbreak of SARS when it first emerged in the country in 2002: it concealed information from the public and did not inform the WHO for several months, presumably in order to maintain the status quo and prevent economic fallout.

But experts say that’s unlikely to be repeated in this case.

As Dr Matt Killingsworth told Mamamia, China is likely to have learned from the global outrage that followed its handling (and almost certainly exacerbation) of the SARS outbreak.

“If China is caught in a cover-up again, it undermines China’s legitimacy at a really important time in how China is evolving both economically and socially, and undermines its ability to conduct business internationally,” he said.

“President Xi [Jinping] has called for tough measures. He said the [Communist] Party, committees, governments and relevant departments at all levels should put people’s lives and health first. And the Chinese government has warned that anyone who hides infections will be forever nailed to history’s pillar of shame.”

For up-to-date information on the novel coronvirus outbreak, visit the Australian Government Department of Health website. For associated travel warnings visit via the SmartTraveller website.

Feature image: Getty.