In a report published today, Defra confirmed two further cases of low-pathogenic H7N3 avian influenza in free-range poultry in Norfolk. Both flocks were owned by the same farmer and comprised 8,000 chickens each. They have now been culled.

It is clear that the infection at these two farms pre-dates that at the intensive broiler plant where the virus was first diagnosed on 27 April. All three farms are within 3 km of each other.

The free range flocks were housed, fed and watered in barns but allowed outside access during daylight. This means that wild birds cannot be ruled out as the origin of the original infection.

However, it is not clear how the infection entered the intensive broiler production plant, which operated biosecurity measures to prevent infection getting in. There is some evidence that the virus has increased in its pathogenicity (its ability to cause serious disease) to poultry, as it has spread amongst the domestic flocks, though further test results are awaited to confirm this.

One worker at the broiler plant has developed conjunctivitis as a result of contracting the virus. Defra states that the virus in its current form has only extremely limited implications for human health.

Defra are maintaining livestock movement controls within 1 km or each of the farms and continuing to conduct surveillance of poultry flocks in the area.

It is believed that most highly pathogenic avian influenzas evolve in domestic poultry from low pathogenic strains introduced from wild birds. The pattern of infection in this case seems to fit this theory.

No further cases of highly pathogenic H5N1 have been discovered in the UK since the single whooper swan in Fife on 5 April.

There are no restrictions on access to the countryside or feeding garden birds as a result of this recent development, and no reason for alarm.

Government officials today confirmed that the H5N1 positive swan discovered in Cellardyke, Scotland was a whooper swan, not as previously thought a mute swan.

Initial identification had been hampered by the advanced state of decay of the carcass and the species was only confirmed through DNA profiling.

Whooper swans are migratory. The Icelandic breeding population winters in north-west Europe, including Britain and Ireland, the Low Countries and the Baltic. H5N1 has been confirmed in several whooper swans in the Baltic during February and March.

It seems plausible that the bird found in Scotland may have originated in this region and was attempting to migrate back to Iceland to breed, before becoming too sick to continue and alighting on the sea.

If this is the case, then it may be an isolated incident. However, it would be wise at this stage, not to dismiss the alternative theory that the swan was wintering in the UK (either in Fife or elsewhere) and contracted the virus locally from another species of waterfowl.

For this reason, the current restrictions should be kept in place and further surveillance of wild birds carried out.

The Scottish Executive has now set up a 3km 'protection zone' around Cellardyke, where the dead swan was found, and a 10 km 'surveillance zone' around that. The Scottish Executive have also set up a 2,500 sq km ‘wild bird risk area’, stretching along the East coast, around the site of the outbreak. Within these three areas, all poultry are to be brought indoors, and there will be increased surveillance of wild bird populations.

This ‘wild bird risk area’ includes our Vane Farm, Strathbeg and Loch of Kinnordy Nature Reserves. In the light of recent events in the area, the RSPB is carrying out daily surveillance of these reserves. All our nature reserves remain open, and they are still welcoming visitors – there is no need to stop visiting the countryside.

After the dramatic news of H5N1 being detected in the UK, many people are understandably alarmed if they find a dead bird. If you do find a sick or dead bird, the following advice has been issued by Defra: If you find one or more dead swans/wild fowl (ducks and geese); more than 3 dead birds of the same species or more than 5 dead birds of different species, in the same place, you should contact the Defra Helpline (08459 33 55 77). 

Currently the Helpline is available between the following hours Monday - Friday 6 am to 10 pm and Saturday - Sunday 6 am to 10 pm. You will be asked for details of your finding and its location. If the dead bird is a single, small garden, or wild bird then you do not need to call Defra. 

Please see 'The bird breeding season begins' and 'Your questions answered' for more information by clicking on the links to the left.

Government sources confirmed today that the virus isolated from the dead swan in Fife, east Scotland was the Highly Pathogenic H5N1 type.

It is stressed that this is a disease of birds and it is extremely difficult for humans to contract it. Nevertheless, you are advised not to touch any sick or dead birds. It is extremely unlikely that avian influenza could be transmitted to people by feeding birds in the garden, but observing sensible hygiene measures is always recommended.

The countryside remains open and you are urged to continue to enjoy its scenery and wildlife.