The coronavirus, a new form of viral pneumonia, has already claimed more than 200 lives and infected thousands in China.
Outside of China, more than 40 cases have been confirmed elsewhere in the world -including eight now in the UK.
Other cases have been found in Thailand, Taiwan, Japan, South Korea, the US, Vietnam, the UAE, Singapore, Malaysia, Nepal, France, Canada, Germany and Australia.
Almost all involve Chinese tourists or people who visited Wuhan.
In response to the outbreak of new strand of coronavirus, the World Health Organisation has declared the situation a "global emergency”.
Meanwhile the Chinese government is keen to avoid a repeat of SARS, or severe acute respiratory syndrome, another coronavirus that started in 2002 and killed nearly 800 people.
But what is this new strand and what effect does it have on people?
Here’s what you need to know.
What is the virus?
Coronaviruses (CoV) are a large family of viruses causing illness ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV).
It is called a novel coronavirus (nCoV) when a new strain has been identified in humans.
Public Health England (PHE) is currently using the name Wuhan novel coronavirus (WN-CoV) for the new strand - named after where it was discovered - until there is an internationally accepted name for the virus and the disease or syndrome it causes.
You may also see it referred to as the 2019 novel coronavirus (2019-nCoV) elsewhere.
Where did the virus come from?
On December 31 last year, the World Health Organization was informed of a cluster of cases of pneumonia of unknown cause in Wuhan City, Hubei Province, China.
On January 12 this year the novel coronavirus had been identified in samples obtained from cases.
Initial analysis suggested that this was the cause of the outbreak.
Many, but not all, of the cases identified in Wuhan had been to or worked in a seafood and live animal market in the city (Huanan South China Seafood Market).
This market was closed on January 1, 2020, and sanitised.
The majority of cases have been in China, but the virus has also been found in Thailand, Japan, South Korea, the US, Vietnam, Singapore, Malaysia, Nepal, France, Australia and Canada.
What are the symptoms?
Fever, fatigue and dry cough are the main symptoms in the early stage of illness and some patients may not progress to more severe illness, such as pneumonia, according to PHE.
Dyspnoea – a condition that causes difficulty with breathing - is said to be common in hospitalised patients, while vital signs were reported to be generally stable at the time of admission.
Older patients with an underlying disease were more likely to progress to severe disease.
How is the virus passed on?
Some coronaviruses are passed on easily from person to person, while others are not.
This illness can be passed on through coughs, sneezes and touching infected surfaces.
Little is known about WN-CoV at this stage and investigations are ongoing but "information to date indicates human-to-human transmission is occurring", according to government advice.Other coronaviruses are airborne and can be passed on between humans.
The Chinese health minister has warned the ability of the virus to spread was getting stronger and accelerating, and that the disease is infectious before symptoms start to show.
Should tourists avoid any countries?
Wuhan remains in lockdown and Britons have been advised against travel to Hubei province by the Foreign Office.
The guidance also added: “If you are in this area and able to leave, you should do so. This is due to the ongoing novel coronavirus outbreak.”
As of January 28, the Foreign Office has warned against "all but essential travel" to mainland China.
The British embassy in Beijing has said transport to get UK citizens out "may happen quickly and with short notice".
Is there a vaccine?
When a disease is new, there is no vaccine until one is developed.
It can take a number of years for a new vaccine to be developed, according to WHO.