Government authorities confirmed the outbreak of the H5N1 strain of bird flu at a local chicken farm on Thursday. Jolly Choi, spokeswoman for Hong Kong's agriculture, fisheries, and conservation department said that earlier tests on Dec 9 were positive for an H5 virus, but further testing showed that three chickens found dead on the farm had the H5N1 subtype.

Choi said that no new measures were required other than those that have been implemented.

To prevent the spread of this deadly virus, government authorities ordered the slaughtering of over 80,000 birds in the farm and nearby poultry operations. A 21-day ban on poultry imports which would last through the Christmas holiday has also been imposed.

York Chow, Hong Kong's secretary for food and health said that experts are focusing on two lines of investigation: a possible biosecurity lapse at the farm and if a change in the circulating virus has hobbled Hong Kong's poultry vaccine.

Poultry trade representatives in Hong Kong said that smuggled fertilized eggs from China could be the source of the recent H5N1 outbreak.