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Avian Influenza (Dorset)

Volume 470: debated on Tuesday 15 January 2008

Between 27 December and 4 January three mute swans were found in a swannery and its vicinity near Chesil Beach; preliminary reports suggest that two of the swans were still alive when located but were euthanised due to injuries and poor condition. The third was already dead. Two were found through regular patrols by the swannery’s staff as part of Defra’s routine dead wild bird surveillance programme, and a third was found by a member of the public.

Targeted surveillance for avian influenza in wild birds is in place throughout the UK and focuses on species that are most likely to spread the disease and on high risk areas where there is a greater abundance of poultry and waterfowl. More than 6,000 birds were tested last year alone. The numbers of birds tested is in part dependent on the numbers of birds found dead by regular patrols of certain wetland reserves or reported by the public. There have been over 2,000 patrols undertaken since the start of this migration period in September and October at over 200 sites. The number of dead birds can be lower during a milder year. No cuts have been made to active patrolling or testing and in some areas patrolling has been increased due to national and international avian influenza incidents.

In the case of the swans found in Dorset, there was no immediate cause to suspect disease, and as the cases did not appear unusual given mortality rates among the local swan population, the swannery held the carcasses until Monday 7 January, when they first reported them to Defra. The Meat and Livestock Commission (MLC), which is Defra’s contracted collection agent for the wild bird surveillance programme, then collected the carcasses and delivered them on the same day to the local regional laboratory of the Veterinary Laboratories Agency (VLA), at Starcross in Exeter. There, post mortem examinations and sample collections were carried out prior to courier dispatch of the samples for Avian Influenza testing at the VLA in Weybridge, Surrey, which is the World Animal Health Organisation (OIE) reference laboratory for avian influenza. This was conducted as part of routine surveillance, and the collection, storage and transportation of the samples to the laboratory, and their testing, were entirely consistent with international standards.

On the evening of Wednesday 9 January, preliminary results indicated the presence of H5N1, but not the pathogenicity. The VLA immediately informed Defra which sought expert ornithological advice on the following day about the restrictions that might be needed. At lunchtime on 10 January, following further laboratory tests, the Acting Chief Veterinary Officer was able to confirm that highly pathogenic H5N1 avian influenza had been found in the three swans.

Wild bird control and monitoring areas were immediately put in place around the swannery. The boundary of the control area has been set to meet EU requirements for a 3 km minimum radius, and encompasses an appropriate area around Chesil Beach and Portland Bill. The boundary of the monitoring area meets the minimum requirement for a 10 km radius and an appropriate area around the wild bird control area. The boundaries were determined following advice from expert ornithologists who took into consideration the location of local bird reserves and the presence of wild bird populations. This advice also gives us some confidence that birds in this area have not moved widely and therefore there is no scientific justification for requiring birds to be housed, or bird gatherings to be banned, in the rest of the country outside the wild bird monitoring area.

Inside these areas, no poultry or other captive bird movements from premises are permitted, all birds must be housed or otherwise isolated from contact with wild birds, no wild birds may be hunted, and all bird gatherings are banned. Biosecurity measures apply on premises where poultry or captive birds are kept. We are currently working with industry to determine the availability of licences for movements from premises and for hunting of wild birds.

Soon after confirmation, Defra, using the poultry register, sent a text message to all those who had registered a mobile phone number with the register. Two messages were sent; one to keepers in the control and monitoring areas, and one to all those in England and Wales. Known keepers registered on Animal Health’s database—excluding those who had already received a message via the poultry register—were also sent a voicemail message.

On 11 January, information packs were posted to all known poultry premises in the control and monitoring areas. These packs have also been distributed by Animal Health vets during surveillance visits in the field.

One member of the public and 11 reserve staff have been assessed for possible risk to their health by the Health Protection Agency (HPA), seven of whom have been given precautionary courses of antiviral drugs because of their close contact with infected or potentially infected birds. None of these people is ill. Vaccination with seasonal human influenza vaccines has also been administered to this group of people. The HPA advise that the risk to the general public is very low.

While surveillance and testing continue, no evidence of disease has been found in domestic poultry or other captive birds. There will be no culling of wild birds because such action might disperse birds further creating a risk of disease spread. While our policy on vaccination is kept under continuous review, experts advise us that it would not assist disease control in this case.

A full epidemiological investigation is under way to determine the source of infection. The strain of the virus identified is very similar to that causing the cases confirmed in the Czech Republic, Romania and Poland mid to late last year. It is less similar to that found in East Anglia in November. We are also carrying out increased surveillance in the area to look for any further carcasses of wild birds for testing, in addition to our routine collection and testing of certain species of dead wild birds in areas of the rest of the country with higher wild bird and poultry density. All premises in the control area with domestic poultry are being visited by Animal Health staff to look for presence of disease. We are making a rapid assessment of the risk to captive birds and poultry in the wider area so that we can consider whether we need to further enhance surveillance of wild and captive birds, and advise local poultry keepers about preventative measures they should take.

Trade in poultry and poultry products to other EU member states from outside the control and monitoring areas can carry on largely unaffected. Exports of poultry and poultry products to non-EU countries are already very limited because, following the H5N1 outbreak in Suffolk in November last year, the UK is currently not officially free from avian influenza according to the OIE—the World Organisation for Animal Health. As these new cases have been found in wild birds our intention to regain our “officially free” status later this year is not affected.

I wish to stress as before that avian influenza is largely a disease of birds. The virus does not easily cross from birds to infect humans; in almost all instances, such transmission requires extremely close contact with infected birds, particularly faeces. The fact that disease has been found in wild birds rather than poultry makes no difference to the human health risk.

I would also like to take this opportunity to thank all those in Defra, Animal Health, other partners and especially the relevant local authorities for their usual professional and rapid response.