The new coronavirus which appeared late December has claimed more than 420 lives, infected more than 19,800 people in China, and spread to 24 countries.
Here is a timeline.
On December 31, 2019, China alerts the World Health Organization (WHO) to cases of pneumonia in Wuhan, a central industrial city of 11 million people.
Several infections are traced to a Wuhan market which is shut on January 1.
As infections rise, Chinese officials say on January 7 they have identified a new virus from the coronavirus family. It is named 2019-nCoV.
China announces its first death in Wuhan on January 11.
Two days later the first case outside China is reported in Thailand, a woman who arrived from Wuhan.
Japan reports its first case, also originating in Wuhan, on January 16.
The United States, Nepal, France, Australia, Malaysia, Singapore, South Korea, Vietnam and Taiwan confirm cases over the following days.
The US is among those that starts screening flights from Wuhan.
By January 20, nearly half of China’s provinces are affected, including Beijing, Shanghai and Shenzhen.
The illness can be transmitted between humans, a Chinese infectious disease expert says.
Asian countries introduce airport screenings of arrivals from Chinese high-risk areas.
Wuhan under quarantine
Wuhan is placed under quarantine on January 23, with transport links cut there and in other Hubei province cities, affecting more than 50 million people.
The WHO says the global risk is “high.”
Beijing cancels events for the Lunar New Year starting on January 25. Several landmarks are closed. The first two deaths outside Hubei.
On January 24, the first three cases are recorded in Europe, in France.
Beijing extends the holiday to limit population flows.
On January 27, the US and Germany tell their citizens not to travel to China.
On January 28, Germany and Japan announce the first two confirmed instances of human-to-human transmission outside China.
On January 29, the US and Japan become the first of many nations who will start evacuating their citizens from Wuhan.
The first cases appear in the Middle East, in the United Arab Emirates.
Some airlines suspend their China flights, while others reduce their links.
Foreign companies shutdown Chinese factories and shops, including Toyota and Starbucks.
On January 30, Russia shuts its border with China.
The WHO declares an international emergency.
On January 31, as Britain, France and North Korea airlift their nationals, Italy declares a six-month state of emergency.
First death outside China
On February 2, Wenzhou, around 800 kilometers from Wuhan, becomes the second city to be locked down.
The Philippines reports the first coronavirus death outside China – a man from Wuhan, the WHO says.
With the virus expected to impact on economic growth, China says it will pump 1.2 trillion yuan (US$173 billion) into the economy.
Chinese stocks collapse
On February 3, Chinese stocks collapse, with Shanghai plunging more than 7% on the first day of trading since the holiday.
China accuses Washington of spreading “panic” after it bans foreign nationals from visiting if they have been in China recently, a move followed by other countries and cruise lines.
China says it “urgently needs” masks and its state anti-doping agency temporarily suspends testing.
China death toll passes SARS
After the single-biggest daily increase in deaths – 57 – the 362 fatalities from the new coronavirus passes the 349 mainland deaths from Severe Acute Respiratory Syndrome (SARS) crisis in 2002-2003.
But with 19,856 confirmed infections, the mortality rate for the new coronavirus is far lower at around 2.1%, compared with 9.6% for SARS.