More than 14,800 new cases of the coronavirus have been reported in China's Hubei province - the epicentre of the outbreak.
Health officials in the country have been using a new method to identify cases of COVID-19, the disease which is caused by the coronavirus.
There had been optimism that the number of infections was beginning to slow down. On Tuesday, China had reported its lowest number of new COVID-19 cases in two weeks.
But the World Health Organisation had warned that the apparent slowdown in the spread of the coronavirus epidemic should be treated with "extreme caution".
A total of 48,206 cases of COVID-19 are now being treated in Hubei province alone, most of them in the city of Wuhan.
According to the region's health commission, 33,693 people are still being treated in hospital - and 5,647 of them are said to be critically ill.
More than 158,000 people who came into close contact with COVID-19 patients are being tracked in Hubei, and 77,308 people are under medical observation.
In other developments:
- Dozens of Britons rescued from Wuhan are going to be released after two weeks of quarantine in Merseyside
- London has had its first confirmed case of COVID-19, taking the total number of patients in the UK to nine
- The World Health Organisation has warned "this outbreak could still go in any direction"
- Several events - including the Chinese Grand Prix in Shanghai and the Mobile World Congress in Barcelona - have been cancelled
- A second patient has tested positive for COVID-19 in San Diego, California