The risk posed to Australians by a new strain of coronavirus is low, but health authorities say there is a need to be vigilant.

CORONAVIRUS ORIGINS AND SPREAD:

* The World Health Organisation began responding to cases of unexplained pneumonia in Wuhan, central China, on December 31, 2019.
* The virus is believed to be animal in origin having jumped from animals to humans, with Chinese authorities having linked initial cases to a fish market in Wuhan.
* Cases have been confirmed in other parts of China as well as Thailand, South Korea and Japan. The majority of people said they had travelled from Wuhan.
* There have now been 222 confirmed cases with four confirmed deaths, but mild cases could be going undetected.
* 'Novel coronavirus' is a term given to new strains of coronavirus, which is from the same family as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS).
* WHO says the virus is capable of limited human to human transfer, with Chinese health workers confirmed to have caught the bug.

WHAT'S HAPPENING IN AUSTRALIA?

* Queensland health authorities confirmed on January 21 one man was being isolated in his Brisbane home as they test him for the virus.
* The man had recently travelled to Wuhan to visit family and returned with a respiratory problem.
* Australian border authorities are screening passengers travelling into Sydney on direct flights from Wuhan.
* Health authorities say the risk to the Australian public is "relatively low" but caution is required.

HOW DOES IT SHOW UP?

* High fever is the most common symptom of the virus, but other symptoms include a cough, breathlessness and sore throat.
* In severe cases, infection can cause pneumonia, severe acute respiratory syndrome, kidney failure and even death, the WHO says.
* The virus has an incubation period of one week, meaning people with the bug might not show symptoms over that period.
* All the confirmed cases have been in adults and no children have been infected.
* In the severe or fatal cases, the people were already sick or had other medical conditions.

(Source: Federal Health Department; WHO website.)