Avian influenza

The country is in the grip of an epidemic caused by a virus that is bringing massive loss of life.  It is not Covid, although that is still with us, and the mortality is amongst birds not humans.  Avian influenza or bird ‘flu has become a serious threat.

            It is not supposed to be like this, at least it used not to be.  The spread of bird ‘flu was thought to be caused by migratory birds so the outbreaks occurred when birds come here for the winter and died away in summer.  But now it seems to have become endemic and is with us all the year perhaps because it has become established in seabirds.  Around the coast of the British Isles we have some of the most important colonies of seabirds in the world.  The Farne Islands off Northumberland, for example, are home to around 200,000 including Arctic terns, Atlantic puffins, guillemots, kittiwakes and razorbills. 

There have been over 300 outbreaks of bird ‘flu in seabird colonies with tens, if not hundreds of thousands of deaths.  Even when the epidemic abates, recovery will take time as seabirds typically are long lived, not reaching breeding age until five years old with relatively low reproduction rates.  Nationally the great skua, gannet and sandwich tern are most at risk.  The world population of great skua is put at 16,000 and it is estimated that 64% to 85% have perished at some sites in the northern Scottish islands.  In Cornwall, dead seabirds have been found on beaches and even in towns such as Newlyn and Mousehole.

But it is not just wild seabirds that are at risk.  Millions of domestic poultry are also threatened by this latest strain of highly pathogenic H5N1 virus that is thought to have originated in 1996 in southern China.  In this country, it is a notifiable disease which means that it must be reported to the Animal and Plant Health Agency which will then take action where domestic fowl are involved.  All poultry on the premises will be slaughtered with strict disinfecting and a time limit before restocking is allowed.  A 3 km Protection Zone and a 10 km Surveillance Zone is established with restrictions within them.  All free-range poultry must be housed in the Protection Zone whilst movements, including the release of gamebirds, are restricted in a Surveillance Zone.

There are two main areas of the epidemic in England.  There have been 53 cases this month and over 200 since the H5N1 epidemic started last November, mostly concentrated in the South West and East Anglia, although this is now spreading.  A large area of Norfolk, Suffolk and Essex has been declared a Protection Zone with mandatory housing whilst, on 17th October, the whole country was designated a Protection Zone with strict biosecurity measures enforced.

Most eggs in this country are sold as free-range which means that the hens have an open area outside their houses.  When a housing order is imposed, as it was across the country from 29th November last year to 2nd May this year, the birds are not allowed out.  Eggs are then described as ‘free-range’ for 16 weeks after which they have to be called ‘barn eggs’.  The EU is currently looking at relaxing this regulation to avoid major changes in branding and labelling.

Different species have varying rates of susceptibility to the virus.  Turkeys die very quickly when infected, chickens may take a little longer whilst duck appear to have greater resistance.  Red-legged partridge also show some resistance whilst pheasants are more susceptible.  The shooting season has been severely disrupted by bird ‘flu outbreaks in the spring and summer in the Loire area of France from whence come many of the pheasants and partridges released in this country, either as eggs or chicks.  At one stage it was suggested that the number released might be 50% lower than usual with many shoots scaling back or even shutting down altogether, not helped by the rapid inflation of costs particularly fuel and feed.  Now there is a fear that bird ‘flu might strike and curtail activities still further.

One local estate is particularly at risk with a poultry enterprise and a commercial shoot.  The Benham Estate has around 30,000 hens mostly in fields along the Bath Road selling high quality free-range eggs.  All the birds had to be shut up from November to May but are free at present.  The number of days of shooting has been reduced to about a third with smaller bags on most of those days.  All the estate can do now is to practise the strictest biosecurity measures and hope that bird ‘flu does not come any closer.  Whilst the Benham Estate has managed to keep its permanent staff employed, there are fewer opportunities for beaters and pickers-up.  Other game farms, poultry units and shoots are not so fortunate and there may have been a significant number of redundancies which is unwelcome during a cost of living crisis.