The Centre for Health Protection (CHP) of the Department of Health is investigating a case of influenza A (H9N2) infection - a mild form of avian influenza - involving a 35-month-old girl.

A spokesman for CHP said today (December 23) the girl, living in Sha Tin, developed symptoms of cough, fever, runny nose since late November. She was admitted to the Prince of Wales Hospital and was discharged on December 11. She has now recovered.

Influenza A (H9N2) was detected in the patient´s respiratory specimen.

Investigation is ongoing.

The department will inform the World Health Organization.

Influenza A (H9) is an avian influenza virus which has been isolated from duck and chicken for many years. Infection in humans is rare, and appears to present as a mild disease.

This is the seventh time that H9 viruses was found in humans in Hong Kong. Five females and a male were confirmed to have suffered from H9 infection in 1999, 2003, 2007, 2008 and 2009.

"Hong Kong has a comprehensive avian influenza surveillance programme to detect the presence of any avian influenza in our environment and the possible reassortment of the viruses so that prompt responsive measures can be taken," the spokesman said.

As a precautionary measure, people are reminded to avoid contact with live poultry to minimise the chance of being infected with avian influenza.

"Hands should be washed thoroughly with soap and water after handling live poultry.

"To build up good body resistance against influenza, the public are encouraged to maintain a balanced diet, do regular exercise, and have adequate rest. They should not smoke." he said.