According to Hunan provincial disease control and prevention centre, eight cases have been reported in the past 16 days, including three deaths.
A new case was reported in Hunan yesterday. The patient, a 36-year-old woman from Hengyang City, is in critical condition and receiving medical treatment.
She had contact with poultry before falling ill, state-run Xinhua news agency reported.
Another 11 H7N9 cases have been reported in Guangdong, with two deaths.
H7N9 is a bird flu strain first reported to have infected humans in March 2013 in China. It is most likely to strike in winter and spring.
PTI