Chinese officials are taking measures to prevent the spread of H7N9, a deadly strain of bird flu that has already killed 22 people this year.
Three members of the same Chinese family contracted H7N9 in Hangzhou, the capital of the eastern province of Zhejiang, the worst-affected by the current spike in cases.
Local authorities are set to close live poultry markets in major cities, according to reports in official media.
Live poultry trading will be halted in cities in coastal Zhejiang province from February 15, and neighbouring Shanghai will stop trading for three months beginning on Friday.
So far this year, China has confirmed 110 human H7N9 cases, including 22 deaths, according to an AFP news agency's tally of reports by local authorities.
By comparison there were 144 infections and 46 deaths in all of 2013, according to official figures.
Zhejiang alone has seen 53 cases this year, almost half the national total, and 12 deaths.
On Tuesday, Hong Kong's only wholesale poultry market began culling 20,000 chickens and suspended imports of fresh poultry from mainland China for three weeks after the discovery of the H7N9 bird flu virus in a batch of live chickens from the southern province of Guangdong.
The government order took effect on Tuesday, two days before the start of the Chinese New Year, when poultry sellers generally anticipate a surge in sales.
China's human H7N9 outbreak began in February 2013 and sparked fears the virus could mutate to become easily transmissible between people, potentially triggering a pandemic.
Both Chinese authorities and the World Health Organisation (WHO) have said there has been no evidence so far of sustained human-to-human transmission.
But limited spread, such as between relatives in close contact, is possible, and there have been previous such family clusters.
The WHO said on Wednesday that the spike in cases this year was not surprising due to seasonal factors, rather than a virus mutation.
"Today there is no evidence that the characteristics of the virus have changed in a way that would explain an increase in cases and change in case fatality," WHO Representative in China Bernhard Schwartländer told the AFP news agency.