In the UK, when outbreaks of Highly Pathogenic Avian Influenza (HPAI), such as H5N1, occur - as seen at Linton-on-Ouse, Wetherby and Easingwold in North Yorkshire - a set of rigorous physical control measures are implemented to eradicate the virus, prevent its spread, and reduce the risk of recurrence. These controls are based on statutory disease control strategies developed by the Animal and Plant Health Agency (APHA), the Department for Environment, Food and Rural Affairs (Defra), and devolved administrations in Wales, Scotland, and Northern Ireland.

1.   Protection and Surveillance Zones

·         3km Protection Zone (PZ): Immediately surrounding the infected premises, this zone enforces strict movement controls. Movement of poultry, eggs, vehicles, and related materials is prohibited without a license. Premises are subject to clinical inspections, surveillance visits, and mandatory biosecurity measures, including disinfection protocols.

·         10km Surveillance Zone (SZ): A wider zone surrounding the PZ, this area is used to monitor and detect any secondary spread. Poultry premises within this zone are subject to movement restrictions and increased surveillance, including record-keeping and mandatory reporting of bird mortality or signs of illness.

(Source: Defra – Notifiable Avian Disease Control Strategy for Great Britain)

2.   Culling and Disposal ("Stamping Out")

Once avian influenza is confirmed, all poultry and captive birds at the affected premises are humanely culled to eliminate the virus reservoir. Carcasses, contaminated bedding, feed, and equipment are then safely disposed of via incineration or rendering at approved facilities. This is essential for halting viral transmission.

(Source: APHA Disease Control Measures)

3.   Cleansing and Disinfection (C&D)

Following culling, comprehensive cleaning and disinfection of the premises are carried out using Defra-approved disinfectants. All organic material is removed before disinfectant application. The site must pass official inspection and verification before it can be considered disease-free or restocked.

(Source: Defra List of Approved Disinfectants)

4.   Movement Restrictions

During the enforcement period, movements of live birds, eggs, poultry meat, litter, manure, feed, vehicles, and personnel are strictly regulated under license. These controls are critical to containing the virus within the restricted zones and preventing transmission between farms and regions.

(Source: UK Avian Influenza (Bird Flu) Guidance)

5.   Active Surveillance

Government veterinary officials and APHA carry out targeted surveillance within the protection and surveillance zones. This includes clinical inspections and sampling of poultry and other captive birds to identify any additional infections. Premises are also monitored for compliance with biosecurity rules, and poultry keepers must report any increase in illness or deaths.

(Source: APHA Guidance – Avian Influenza Surveillance)

6.   Biosecurity Enforcement

All poultry keepers in affected areas are required to adopt enhanced biosecurity measures. These include housing birds indoors or using netting to prevent contact with wild birds, restricting access to poultry areas, using foot dips and dedicated clothing, and thorough cleaning of equipment and vehicles. Non-compliance can result in enforcement actions.

(Source: Defra – Avian Influenza Prevention Zone Measures)

7.   Wild Bird Control and Monitoring

Wild birds are a known reservoir for avian influenza. Therefore, surveillance of wild bird populations is undertaken, including testing of dead wild birds reported by the public. This helps assess the wider environmental risk and informs decisions about national control measures.

(Source: APHA – Wild Bird Avian Influenza Surveillance Reports)

De-escalation Following Disease Eradication

The revocation of protection and surveillance zones - such as those near Linton-on-Ouse, Ravensthorpe, and Glyn Ceiriog - occurs only after:

• Completion of culling, cleansing, and disinfection operations.
• Expiry of the minimum standstill periods (e.g., 21 days post-C&D for PZs).
• Negative results from active surveillance in the zone.

Only once APHA confirms that there is no further evidence of infection and that all controls have been met are zones lifted, as reflected in the government’s rolling outbreak updates.

(Source: Defra – Avian Influenza Outbreak Updates)