Its emergence has fueled fears of a deadly epidemic as hundreds of millions of people travel in China, or around the Asian region, during the Lunar New Year holiday.
Coronavirus is a large family of viruses, which include severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).
Common symptoms include a runny nose, cough, sore throat, and possibly a headache. Those who have a weakened immune system, particularly the young and the elderly, are at risk of the virus turning into a more serious respiratory tract illness.
Authorities said the Wuhan coronavirus was passed from animals to humans; can be spread from person to person; and appears to cause pneumonia in people who have weakened immune systems.
It is thought to be milder that SARS and MERS and take longer to develop symptoms. Patients to date have typically experienced a mild cough for a week followed by shortness of breath, causing them to visit a hospital.
Experts are now trying to understand how it is being transmitted, who is at most risk and whether transmission is occurring mostly in hospitals or in the community.
In one instance, 14 doctors and nurses operating on a patient -- who was not known to be carrying the virus -- were all infected with it, suggesting it can be spread relatively easily.
Where is this happening?
Where it started: Ground zero
The outbreak emerged last month in the largest city in central China, Wuhan, a city of 11 million people in Hubei province.
Officials linked it to Huanan Seafood Wholesale Market, saying wild animals sold there are the likely source of the virus. The market has been closed since January 1 for disinfection and officials are scrambling to discover its animal source.
Snakes -- the Chinese krait and the Chinese cobra -- may be responsible for transmitting coronavirus to humans.
Scientists in China say that the virus might have jumped from bats to snakes, which were sold in the local seafood market in Wuhan, and then to humans.
However, how the virus could adapt to both the cold-blooded and warm-blooded hosts remains a mystery, and further tests are necessary to determine the source animal.
At least 30 people died in the province, many of them elderly and suffering from pre-existing conditions.
As deaths mount in the city, officials imposed a number of new measures including the postponement of New Year celebrations in Wuhan, a ban on tour agencies from bringing groups of people out of the city and thermal monitors and screening in public spaces.
From the first reported case in December, in Hubei province, the virus has spread to almost all of China's administrative regions this week.
The country has adopted prevention and control measures that are typically used for major outbreaks such as plague and cholera. This means health officials will get sweeping powers to lock down affected areas and quarantine patients.
Wuhan "temporarily" closed its airport and railway stations on Thursday for departing passengers, and all public transport services are suspended until further notice.
The city's coronavirus task force also announced the closure of highways out of the city.
Meanwhile, the city made it mandatory for everyone to wear face masks in public places after confirmed coronavirus cases passed the 500 mark.
Authorities in China have imposed ind