Avian influenza (bird flu)

This guidance is for Scotland

Avian influenza is a highly infectious viral disease affecting the respiratory, digestive and/or nervous system of birds.

The severity depends upon the strain of the virus and the type of bird infected. Some strains - known as 'highly pathogenic avian influenza' - can cause severe disease in poultry, with a high death rate. The disease can develop so rapidly that birds may die without showing any previous signs of disease.

Other strains - known as 'low pathogenic avian influenza' - usually result in milder, less significant disease. However, certain low pathogen strains can mutate into highly pathogenic strains.

Possible impact of the disease

All bird species are thought to be susceptible to avian influenza. Migratory birds such as wild ducks and geese can carry the viruses, often without symptoms of illness, and show the greatest resistance to infection. However, domestic poultry flocks are particularly vulnerable to epidemics of a rapid, severe and fatal form of the disease.

Legislation and processes for management of the disease are different, depending on the circumstances of the outbreak - for example, whether the high pathogenic strain H5N1 is confirmed in poultry, other captive birds or wild birds, and whether the disease occurs at a farm, slaughterhouse or border inspection post.

The highly pathogenic H5N1 strain has shown the ability to jump the species barrier occasionally and cause severe disease in humans. It has not shown the ability to move easily between humans, but this is a cause for concern (see below).

Clinical signs

The severity depends upon the strain of virus and the type of bird infected. Birds infected with highly pathogenic avian influenza may die suddenly or show a range of clinical signs.

Individual birds with highly pathogenic avian influenza may show the following symptoms:

• nervous signs (tremors and incoordination)
• depression, sneezing and coughing
• swollen, congested and oedematous wattles
• haemorrhages on the hock (lower part of leg)
• diarrhoea

In the flock, symptoms can be:

• unusual quietness, decreased activity levels
• decreased levels of vocalisation
• decreased levels of feed and water consumption
• decreased egg production

It is important to note that when infection is due to a highly pathogenic form of avian influenza, the onset of clinical signs is sudden, severe, short lasting and mortality is extremely high (sometimes 100%).

Avian influenza is a notifiable disease. If you suspect any type of bird flu, you must tell the Animal and Plant Health Agency (via the local APHA office) immediately. Failure to do so is an offence.

Procedures when disease is confirmed

The premises where disease is confirmed will be put under restriction so poultry or other captive birds cannot move on or off. It will be referred to as the infected premises. An approved disinfectant must be used to disinfect footwear, clothing and vehicles before entering or leaving the premises.

A protection zone of 3 km and a surveillance zone of 10 km are put in place around the infected premises where the disease has been confirmed. There are certain restrictions for keepers of poultry and other captive birds that are within the protection and surveillance zones. Keepers can now apply for a licence to move poultry from a restricted zone, using APHA's online animal disease licensing service.

If avian influenza is confirmed, it will be controlled in line with the contingency plan for exotic notifiable diseases and the notifiable avian disease control strategy will be implemented.

Biosecurity

Biosecurity measures should be practised routinely. Avian influenza is spread through bird-to-bird contact and indirectly through contaminated feed, water, equipment, etc.

The boots, clothing and hands of any person who has been in contact with infected animals can spread the disease.

The Scottish Government has published information on biosecurity and the measures you can take to protect your birds from disease, specifically avian influenza. It includes posters on protecting your birds from avian influenza.

There is also guidance on the GOV.UK website on how to spot and report the disease.

Legislation applicable to avian influenza

The Animal Health Act 1981 provides powers for the control of outbreaks of avian influenza. It was amended in 2006 to provide more powers to deal with various diseases, including avian influenza and Newcastle disease.

The Act provides for the slaughter of diseased poultry, poultry suspected of disease, poultry exposed to disease and poultry that the Scottish Ministers thinks should be slaughtered to prevent the spread of disease (a 'firebreak' cull).

The Diseases of Poultry (Scotland) Order 2003 introduced a number of key amendments to the Animal Health Act 1981. The definition of poultry within section 87(4) of the Animal Health Act 1981 was amended to include all birds (including those in captivity) and the definition of disease in section 88(3) was extended to include all diseases of birds.

The Avian Influenza and Influenza of Avian Origin in Mammals (Scotland) Order 2006 allows for a flexible and risk-based approach to disease control, which will enable industry to continue to operate in a safe and biosecure manner.

The Order contains preventive measures such as:

• power for the Scottish Ministers to declare an avian influenza prevention zone
• ban or limitation of bird gatherings
• separation of birds from wild birds
• surveillance for avian influenza

The Order includes a range of provisions for application in cases of suspected and confirmed avian influenza, both highly pathogenic and low pathogenic.

The Avian Influenza (H5N1 in Poultry) (Scotland) Order 2007 provides for specific requirements in addition to those in the Avian Influenza and Influenza of Avian Origin in Mammals (Scotland) Order 2006 in the event that avian influenza H5N1 is found in poultry. The Scottish Ministers must declare a further controlled zone, termed a restricted zone (RZ). This can be centred on the outbreak point or adjacent to the surveillance zone or another restricted zone.

The Avian Influenza (H5N1 in Wild Birds) (Scotland) Order 2007 provides controls in the event that avian influenza H5N1 is found in wild birds.

The Avian Influenza (Slaughter and Vaccination) (Scotland) Regulations 2006 prohibit vaccination but allow the Scottish Ministers to declare an emergency vaccination zone or a preventive vaccination zone. The Scottish Ministers can also serve an emergency vaccination notice on individual premises. Within the zones or on individual premises, the Scottish Ministers can require the vaccination of poultry and other captive birds. Movement restrictions will apply within the zones.

The Avian Influenza (Preventive Measures) (Scotland) Order 2007 bans fairs, markets, shows or other gatherings of poultry or birds. In practical terms, bird gatherings have been permitted to take place under a general licence, but the organiser must notify their local APHA office that they are going to happen.

The current position in relation to bird gatherings is that gatherings of all poultry and captive birds are permitted, as long as you meet the requirements of the bird gathering general licence.

Keepers of poultry and other captive birds are required to register their flocks on the new Scottish Kept Bird Register (SKBR) by 1 October 2024. Previously, only flocks with 50 or more birds were required to be registered (keepers already registered with the Great Britain Poultry Register have until 1 December to register on the SKBR). Keepers are encouraged to register their birds ahead of the legal deadline. See 'Registration and records of poultry and other captive birds' for more information on registration requirements.

The Avian Influenza (Preventive Measures in Zoos) (Scotland) Regulations 2005 restricts the vaccination of birds in zoos. The Scottish Ministers can require that vaccination of birds in zoos is carried out. Certain measures apply to vaccinated birds in zoos, and the Scottish Ministers can require surveillance at these zoos.

Effect on food and humans

Advice from the World Health Organisation is that there is no health risk from well cooked poultry meat or from eggs.

Avian influenza is primarily a disease of birds. Humans can only be infected with the disease through close contact with live infected birds.

Transmission of avian influenza viruses to people remains relatively rare and in most cases occurs as a result of direct contact with infected poultry or other birds or their faeces. At present the virus cannot transfer directly from human to human.

There is concern that the virus may change (or mutate) to emerge as a new virus that is transmissible between people and capable of causing disease in people, birds and other animals.

Public health control measures in any outbreak of avian influenza amongst poultry will therefore aim to protect people against avian influenza and also protect against the risk of any mutation of the virus.

For more information please see the section of the GOV.UK website on avian influenza: guidance, data and analysis.

Disease alerts

Livestock keepers can stay up to date with the latest avian influenza developments via the APHA alert subscription service.

Trading Standards

For more information on the work of Trading Standards services - and the possible consequences of not abiding by the law - please see 'Trading Standards: powers, enforcement and penalties'.

In this update

Keepers are required to register all flocks with by 1 October (with certain exceptions).

Last reviewed / updated: September 2024