Tests are being conducted on the body of a grey heron found in Lok Ma Chau that is suspected to have died from bird flu.
The railway worker who found the heron on Monday is being monitored with six colleagues after preliminary tests on the bird showed signs of avian flu.
A spokesman for the Health, Welfare and Food Bureau said further tests were being carried out to determine if the bird died from the H5N1 virus strain, outbreaks of which have killed 32 people in Thailand and Vietnam this year and prompted poultry culls across Southeast Asia.
'As a precautionary measure, the Centre for Health Protection has traced all seven people who had contact with the dead bird and found they are in good health,' the spokesman said.
Poultry farms within a 2km radius of the site where the bird was found were also inspected.
If confirmed, the heron would be the first bird found with the H5N1 strain of avian flu in Hong Kong this year.