The death toll from a new flu-like coronavirus in China rose to nine on Wednesday with 440 confirmed cases, Chinese health officials said on Wednesday.

Another 2,197 people who came into contact with infected people were isolated, with 765 so far released from observation, National Health Commission vice-minister Li Bin told reporters.

“Recently there has been a big change in the number of cases, which is related to our deepening our understanding of the disease, improving diagnostic methods and optimizing the distribution of diagnostic kits,” Li said.

The virus, originating in the central Chinese city of Wuhan in Hubei at the end of last year, has spread to Chinese cities including Beijing, Shanghai and Macau, as well as the United States, Thailand, South Korea, Japan and Taiwan.