GUANGZHOU, Dec. 16 -- South China's Guangdong Province on Monday reported the second H7N9 bird flu case since Sunday.

The female patient, Zhang, 65, resident of the city of Yangjiang, is in serious condition, the provincial health authority said in a statement.

Guangdong on Sunday confirmed an H7N9 case from a man, aged 39, who is also in serious condition. The province has warned the public of the transmission after the virus was found in its live poultry markets.

Lin Shaochun, vice governor of Guangdong, warned at a meeting on Sunday that the province had entered a season when human infections of H7N9 are highly likely to occur.

The Chinese mainland has reported 142 human infections of the deadly bird flu virus since it emerged in March.

Earlier this month, Hong Kong also confirmed its first two H7N9 cases, including an Indonesian national and a mainland resident.