Avian influenza, also known as bird flu, is a contagious disease caused by a virus loosely related to human influenza. While all bird species are thought to be susceptible, domestic poultry flocks are especially vulnerable, which can rapidly result in epidemics. Since bird flu was first recognised, a century ago there have been more than a dozen strains. Some are almost harmless, while others result in death within hours. The H5N1 form of bird flu is the most dangerous. It is highly contagious among birds, both by air and contact with faeces. Mortality is close to 100%, with many birds dying on the same day they were infected.
They may die suddenly or suffer respiratory problems, swollen heads, loss of appetite and reduced egg production.
The virus is easily destroyed by cooking. It spreads between infected birds, however, so plucking, handling or butchering risks exposure.
The H5N1 strain has killed more than 100 people since emerging in south-east Asia in 2003, but most have fallen ill after long, close contact with infected birds.
If it evolves to be easily transmissible between humans an outbreak could claim 320,000 lives in Britain, according to a Home Office report.
On January 30 2007, turkeys at a Bernard Matthews farm in Holton, Suffolk, started dying. Two days later 800 died. The state veterinary service was contacted and H5N1 was confirmed.
The Government’s plan to tackle bird flu is characterised by surveillance and containment. DEFRA has asked birdwatchers to help provide an early warning against the arrival of the infection and scientists are also involved in examining bird droppings.
The EU says communication between the public, vets and doctors is essential in alerting authorities to any outbreak of flu.
DEFRA provide a dedicated bird flu website which you can visit at www.defra.gov.uk/animalh
