The “whole world needs to be on alert” to fight the coronavirus, the head of the World Health Organization’s Health Emergencies Programme has said.
Dr Mike Ryan praised China’s response to the deadly outbreak, saying: “The challenge is great but the response has been massive.”
The WHO will meet on Thursday to discuss whether the virus constitutes a global health emergency.
The Chinese city of Wuhan is the epicentre of the outbreak.
But the virus has spread across China and to at least 16 countries globally, including Thailand, France, the US and Australia.
More than 130 people have died in China and close to 6,000 have been infected.
There is no specific cure or vaccine. A number of people have recovered after treatment, however.
The WHO’s Dr Ryan said an international team of experts was being assembled to go to China and work with experts there to learn more about how the disease is transmitted.
“We are at an important juncture in this event. We believe these chains of transmission can still be interrupted,” he said.
Scientists in Australia have managed to recreate the new coronavirus outside of China , raising hope that it could be used to develop an early-diagnosis test.
WHO director-general Tedros Adhanom Ghebreyesus, who visited China this week, said most people who contracted the virus were suffering only “milder symptoms”, but about 20% had severe effects such as pneumonia and respiratory failure.
He said that China “needs the world’s solidarity and support,” and that “the world is pulling together to end the outbreak, building on lessons learned from past outbreaks.”
The director-general added that the WHO “deeply regrets” referring to the worldwide risk from the virus as “moderate” in three reports last week instead of “high”.
He described the person-to-person spread of the illness in Germany, Vietnam and Japan as worrying, and said experts would consider it on Thursday when deciding whether to declare a global emergency.
What’s happening in Wuhan?
The city’s residents are enduring an isolated, frightening time. Most forms of traffic have been banned, and more than 50 million people are shut up in their homes, trying to minimise the spread of the virus.
Videos have emerged online of neighbours shouting “Wuhan jiayou!” out of their windows – roughly translated to “Stay strong Wuhan!” or “Keep on going Wuhan”.
The phrase has been trending on Weibo, China’s Twitter-like social media site, with people from around the country posting supportive messages.
“We will get through this. Wuhan jiayou, the whole country is supporting you,” read one comment on Weibo.
By BBC.com