Chinese health officials carefully tracking the 14-day history of a confirmed coronavirus patient say the man contracted the killer virus by standing near an infected person for just 15 seconds.

The 56-year-old male patient had had no previous contact with animals and was not acquainted with any confirmed carriers of the virus in his native district of Jiangbei, in East China’s Zhejiang Province.

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A report by the Jiangbei Health Commission said the man named only as ‘patient 5’ stood next to a confirmed female carrier - 61-year-old ‘patient 2’ - at a booth inside Shuangdongfang market on 23 January.

The report noted that at 7.47am local time, patient 5 came in brief contact with patient 2 for just 15 seconds while neither was wearing a surgical mask.

The same morning, patient 5 then went on to visit two more supermarkets and finally a restaurant before he was diagnosed with the pneumonia-like Wuhan coronavirus on 4 February.

Shuangdongfang market where the patient is believed to have contracted the Wuhan coronavirus from another carrier in just 15 seconds. Credit: AsiaWire / AsiaWire/Australscope

Jiangbei health officials said 19 individuals who had close contact with the five confirmed coronavirus patients - among 18 carriers in the city of Ningbo - have since been put in quarantine.

The number of isolated individuals stood at 92 as of 5th February, the commission said.

Wuhan International Convention and Exhibition Center's "Fangcang hospital" receives patients. Credit: Barcroft Media / Barcroft Media via Getty Images

The update comes as officials confirmed the death toll from the coronavirus outbreak in mainland China has reached 636, with 3143 new infections reported on Thursday.

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What is the coronavirus?

Coronaviruses are a group of viruses that can cause a range of symptoms including a runny nose, cough, sore throat and fever. Some are mild, such as the common cold, while others are more likely to lead to pneumonia.

The latest strain was discovered in the Chinese province of Wuhan.

How do you get coronavirus?

China says the virus is mutating and can be transmitted through human contact.

It’s primarily spread through a sick person coughing or sneezing on someone but a person could also become infected through contact with the virus particles on a surface, NSW Health warns.

What are coronavirus symptoms?

Symptoms include fever, cough and difficulty breathing. Most of those affected are older people and those with underlying health conditions.

How dangerous is the coronavirus?

The virus has caused alarm because it is still too early to know how dangerous it is and how easily it spreads between people.

So far, at least 638 people have been killed and thousands more infected – nearly all in China.

How do you treat coronavirus?

As it stands, there is no vaccine for the virus and because it is new, humans have not been able to build immunity to it.

A group of Melbourne researchers have been tasked with finding a vaccine, while China is testing the HIV drug Aluvia as a treatment.

How do I protect myself from coronavirus?

WHO’s standard recommendations: