Health authorities in south China's Guangdong Province on Wednesday reported two H7N9 human infections.
Both cases were in the city of Dongguan. A 52-year-old woman and a 37-year-old man receiving treatment at local hospitals were both confirmed as infected on Tuesday, the provincial health and family planning commission said in a statement.
Both are in a serious condition, and the woman is critical.
Besides Guangdong, Shanghai Municipality and Fujian and Zhejiang provinces have reported human cases of H7N9 this winter.