Bird flu of the highly pathogenic H5N1 strain has been found in commercial poultry at a farm near Elham, in Kent.
All birds on site will be humanely culled by APHA to help limit the spread of infection, with officials also due to carry out further testing and deep cleaning.
In line with Defra guidance, a 3km protection zone and a 10km surveillance zone has been put in place around the farm to further reduce the risk of the disease spreading.
All bird keepers in a disease control zone must follow rigorous biosecurity standards and not move birds, eggs or meat off their premises without permission from APHA.
All poultry and captive birds in the 3km protection zone must also be housed. Keepers can check if they are in the protection or surveillance zone on the APHA interactive map.
The protection and surveillance zones will remain in place until lifted by the government.
People working directly with the flock at the premises are being offered routine preventative treatment.
The 2021-2023 bird flu outbreak has been the UK's worst and longest ever recorded, with over 330 cases confirmed across the country.
It comes after the government lifted the Avian Influenza Prevention Zone (AIPZ) for poultry and captive birds, introduced to help stop the spread of bird flu.
The risk of avian influenza has now reduced to 'low' for all poultry, the government confirmed last week.
Head of Kent Trading Standards, Steve Rock, said "good housekeeping" was an essential defence against bird flu and key to limiting its spread.
He said: “All Kent bird keepers should continue following Defra rules and immediately report any signs of the disease in their birds to the Defra Rural Services Helpline on 03000 200 301.
“People who have over 50 birds are legally required to register but anyone who keeps poultry, even as pets, should sign up here – if they haven’t already – so they be contacted.”
Kent County Council director for public health, Dr Anjan Ghosh added: "It is important we all play our part in helping to reduce the spread of the disease so please don’t pick up dead or sick birds with your bare hands.
“If you’re out and about in the countryside or on the coast, stick to footpaths and keep dogs on leads to limit contact with wild birds.
"And if you feed birds in your garden, keep feeders clean and always wash your hands after handling them.”
Earlier this month, two poultry workers contracted avian influenza after they came into contact with infected birds, following confirmation of two positive cases in May.
The two people returning positive tests were known to have recently worked on an infected poultry farm in England.
