Following the death of thousands of birds due to the H5 virus attack, Hong Kong has culled 18,000 chickens at a farm outside a quarantined area. Allaying fears, health authorities said the strain was not the kind that killed humans in 1997.

"To prevent the spread of the virus, we decided to depopulate the farm," said the agriculture fisheries and conservation department's deputy director Liu Kwei-kin. He added, "We do not rule out the possibility that this is a new case not connected with the previous cases."