A 2-month-old Hong Kong-born infant who lives in China has contracted a mild strain of bird flu, a health official said Tuesday.

The baby girl, who contracted the H9 strain of avian influenza, is currently isolated at a local hospital and is in stable condition, Thomas Tsang, controller of Hong Kong´s Center for Health Protection, told a news conference.

The baby lives with her family in the southern Chinese city of Shenzhen but recently visited a hospital in Hong Kong after showing symptoms, Tsang said.

He said health officials in the southern Chinese Guangdong province are trying to determine how she caught the virus.

Tsang said Hong Kong has recorded four previous human cases of H9 infections. All patients have fully recovered.

The case came weeks after three dead chickens tested positive for bird flu in Hong Kong, prompting the city to suspend poultry imports for 21 days and begin slaughtering 80,000 birds.

Hong Kong´s biggest bird flu outbreak was in 1997, when the more virulent H5N1 strain jumped to humans and killed six people.

Bird flu has killed at least 247 people worldwide since 2003, according to the World Health Organization.