Deadly strain of bird flu confirmed on Suffolk poultry farm

Government scientists have launched an investigation into the source of the deadly strain of bird flu which was confirmed yesterday at a poultry farm in Suffolk.

It is the second time in a year that the highly lethal H5N1 strain of bird flu has been detected in Britain and scientists are looking at the possibility that it was brought here either by wild, migrating birds, or the movement of goods and people from abroad.

The culling of 6,500 birds, including turkeys, ducks and geese, on the farm has begun after the free-range turkeys on the premises began dying from a mystery illness on Sunday. Meanwhile, restrictions on the movement of birds in Suffolk and much of Norfolk have been put in place.

Fred Landeg, the government's acting chief veterinary officer, said that DNA tests on the virus suggested it was the same strain that caused an outbreak of bird flu in domestic poultry in Germany and the Czech Republic earlier this year.

"This does suggest a possible wild bird source, but at this stage we're keeping an open mind," Dr Landeg said. There is a lake on Redgrave Park Farm, near Diss, where the outbreak has occurred and so there is a possibility that there was mingling between domestic water fowl and wild birds, he said.

However, the Royal Society for the Protection of Birds (RSPB) said that wild birds had been wrongly blamed for the February outbreak of bird flu at a turkey farm run by the Bernard Matthews company, which was later linked to processed meat from Hungary.

Most migrating birds have arrived for the winter and no dead wild birds have been found, said Mark Avery, the RSPB's conservation director. "If migrating wild birds were carrying bird flu, their corpses would have been found north and east of the United Kingdom, the routes that migrating wildfowl take," Dr Avery said.

"But there have been no recent reports of wild birds dying of bird flu in the countries on their migration routes. Jumping to conclusions over the source of bird flu could blind us to courses of action that should be taken," he added.

"We can't rule out wild birds as carriers but we're not even close to knowing that claim is true."

Dr Landeg said that further analysis of the virus's strain may lead to a more precise location for its origin. "We have faced H5N1 once already this year, but there is still significant uncertainty surrounding this outbreak. Swift reporting of disease and stringent biosecurity is essential to controlling this disease and we are working on our established contingency plans," Dr Landeg said.

The H5N1 strain of bird flu does not pass easily to people but when it does it has proved to be extremely lethal. In countries where people and poultry live in close proximity, the virus has killed more than 200 of the 335 people known to be infected – almost half of them in Indonesia.

Last summer, the strain was found in domestic hens in the Czech Republic, wild swans and mallard ducks in France and in both domestic poultry and wild birds in Germany.

There have been no reports of any outbreaks in humans near Europe since deaths were reported in 2006 in Turkey and Azerbaijan. Fifteen people have died in Egypt of bird flu over the past two years.

Scientists fear that the virus may at some point mutate so that it passes more easily between people. "Not all avian influenza viruses have the same ability to infect humans and none to date, other than this current H5N1 virus, has shown this high mortality in humans," said John McCauley of the MRC National Institute for Medical Research in London. "Analysis of the virus over the next day or so will be likely to be able to determine the origin of the virus."

Professor Ian Jones, of the University of Reading, said that it was possible that migratory birds were the source of the outbreak, assuming that the turkeys on the farm were being kept outside.

"Obviously [it is] regrettable ahead of Christmas but [there is] no reason that it should not be contained at this stage," Professor Jones added.

The turkey industry

* Britain consumes about 10 million turkeys each Christmas.

* Retail sales of turkeys each year come to about £374m with imports totalling £97m and exports £48m.

* Retail sales of duck, which is increasingly popular at Christmas, are still only £32m a year, with imports valued at £24m and exports at £10m.

* Geese are another favourite for the Christmas table, but just 600,000 birds are sold each year, with international trade amounting to about £8m a year.

* Chicken is by far the most popular poultry meat all year round with retail sales of about £2.9bn a year.

2007: The year farms were plagued by disease

* Bird flu

Britain's farming annus horribilis began at the beginning of February when vets were called to the Bernard Matthews farm in Suffolk after the deaths of 2,600 turkeys. Days later it was confirmed the avian flu was the H5N1 virus and a cull of 159,000 turkeys was completed. In March, Caroline Flint, the Public Health minister, stated that 850 tonnes of turkey passed through the Bernard Matthews plant and into the food chain during the outbreak, mainly from Hungary. In May and June, two more cases of the low pathogenic H7N3 strain were found in North Wales and Merseyside.

* Foot and mouth

In early August, the spectre of foot-and-mouth disease returned to the UK on a farm near Guildford, Surrey. As a cull began, and a research laboratory at Pirbright – about five miles from the outbreak – was sealed off, British meat exports were banned around the world. By 7 August, a second case of the disease had been confirmed within the zone. The Government subsequently found a "strong probability" the strain of virus behind the outbreak came from two research labs near the site of the infection, and that there was also a possibility that the release of the virus involved "human movement".

* Bluetongue

In an August double whammy for the countryside, the more unusual disease of bluetongue was found in East Anglia, the first such case in the UK. A control zone of 12.4 miles was put in place around affected premises, and the zone included parts of Norfolk, Suffolk, Essex and Cambridgeshire. Although it had appeared in the spring of 2007 in Germany, Belgium, Spain and northern Europe, and questions were asked in the Commons in May about contingency plans, the Government appeared to be caught unaware by the outbreak. Further outbreaks were confirmed in October in Peterborough and at Ashford in Kent.