As a sixth person in China dies from the mystery illness, what is the coronavirus?

The pathogen, known as 2019-nCoV, is thought to be a new strain of coronavirus (Getty)

*The death toll was accurate at the time of publication and has since risen.

A sixth person has died from the mysterious illness spreading across China, authorities confirmed.

The major of the city of Wuhan, at the centre of the outbreak, confirmed the two latest fatalities on Tuesday.

Confirmed cases have jumped to 291, while more than 900 suspected sufferers are under observation, the New Straits Times reported.

The infectious virus has spread throughout China, including in major cities like Beijing and Shanghai, with cases also being identified in Japan and South Korea.

READ MORE: As coronavirus spreads, anxiety rises in China and overseas

The pathogen, known as 2019-nCoV, is thought to be a new strain of coronavirus that has never before been identified in humans.

Like other strains, it typically starts with flu-like symptoms, including fever, cough, shortness of breath and breathing difficulties.

Six coronaviruses are known to infect people, with 2019-nCoV being considered the “seventh”.

The pathogens as a whole are common worldwide, triggering mild-to-moderate upper respiratory tract infections, like the common cold, according to the Centers for Disease Control and Prevention (CDC).

In rarer cases, coronaviruses can lead to lower-respiratory tract infections, such as pneumonia or bronchitis.

These tend to occur in babies, the elderly or those with weak immune systems.

How is 2019-nCoV life-threatening?

The 2019-nCoV fatalities are occurring as a result of pneumonia.

This comes about when a respiratory infection causes the alveoli (air sacs) in the lungs to become inflamed and filled with fluid or pus, according to the American Lung Association.

The lungs then struggle to draw in air, resulting in reduced oxygen in the bloodstream.

“Without treatment the end is inevitable,” the charity Medecins San Frontiers reported.

“Deaths occurs because of asphyxiation.”

READ MORE: Human-to-human transmission confirmed in China coronavirus

2019-nCoV is not the first coronavirus that has got people panicked.

The strain Middle East respiratory syndrome (Mers) kills about three or four in every 10 patients, according to the CDC.

Severe acute respiratory syndrome (Sars) also made headlines in the early 2000s after 774 people died from the infection across dozens of countries, mainly in Asia.

No fatalities have occurred anywhere in the world since 2004, according to the CDC.

2019-nCoV has evoked memories of Sars, with genetic analyses revealing it is more closely related to the pathogen than any other coronavirus.

How does 2019-nCoV spread?

Some strains of coronaviruses only infect animals but have the potential to “jump” to humans.

This is thought to be the case in the 2019-nCoV outbreak, which likely originated from infected animals at a seafood and wildlife market in Wuhan.

Most of those who initially fell ill worked at, or visited, the market.

China's National Health Commission confirmed on Monday it can be passed from person-to-person, like other coronaviruses.

These commonly spread via coughing, sneezing, shaking hands or touching a contaminated object.

The virus enters the body if contaminated hands touch the eyes, nose or mouth.

In rare cases, faecal contamination can be to blame.

READ MORE: WHO emergency group to meet on spreading China virus

There is no specific treatment for coronaviruses, according to the CDC.

If the infection triggers pneumonia, doctors work to combat the complication.

When a virus is to blame - like with 2019-nCoV - pneumonia must be treated via “antiviral medication”, according to the American Lung Association.

US health officials are working on a vaccine against 2019-nCoV, however, it will likely be months before the first stage of trials are underway and more than a year before it is available to the public, CNN reported.

For now, the World Health Organization advises people avoid “unprotected” contact with live animals, thoroughly cook meat and eggs, and stay away from those with flu-like symptoms.