CHANGSHA - Another two human H7N9 avian flu cases have been reported in Central China's Hunan province, bringing the province's number of infections to 13 this year.

According to the Hunan provincial disease control and prevention center,a total of 13 cases have been reported in January, including five deaths.

The two patients who were diagnosed on Thursday, included a 57-year-old surnamed Zou from Xinhua county. He had contact with poultry before falling ill and is in a critical condition.

A 75-year-old man surnamed Xiong from Chenzhou city died Wednesday, bringing the number of deaths from the disease in Hunan to five.

In addition to Hunan, human infections of H7N9 have also been reported in China's Guangdong, Guizhou, Hubei, Henan, Jiangxi and Shandong provinces, as well as in Shanghai, Hong Kong and Macao.

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.