LONDON — Health officials yesterday announced new restrictions on movement near a commercial farm where the deadly H5N1 strain of bird flu was found in turkeys, while authorities culled thousands of birds to contain the outbreak.People involved in the culling and all those who could have come into contact with affected birds were being given an anti-viral drug as a precaution, authorities said.

About 2,500 turkeys died of the virus on the farm owned by Bernard Matthews PLC, Europe’s largest turkey producer. It is the first time the deadly H5N1 strain has been found on a British farm.

The virus was identified as the highly pathogenic Asian strain, similar to that found in Hungary in January, said the Department for Environment, Food and Rural Affairs, or DEFRA.

The Hungarian outbreak was the first known case of the strain within the European Union since August 2006, and led authorities in that country to kill thousands of geese.

Bird flu has killed or prompted the culling of millions of birds worldwide since late 2003, when it began ravaging Asian poultry stocks. It has killed at least 164 people worldwide, but remains difficult for humans to catch.

Professor Pat Troop, chief executive of Britain’s Health Protection Agency chief executive, told the British Broadcasting Corp that the public had little to fear as the virus “doesn’t pass easily from bird to human.”

She said people who had been affected by the disease had lived and worked in very close proximity to birds.

Overnight, government vets were gassing the remaining 159,000 turkeys on the farm in Suffolk county, about 130 miles northeast of London, to contain the outbreak. Deputy Chief Veterinary Officer Fred Landeg said the virus was found in only one of the farm’s 22 turkey sheds.

DEFRA announced new measures to control the movement of birds in the areas surrounding the farm. A 806 square mile restriction zone was set up in which all commercial birds must be isolated from wild birds and all movement of poultry must be licensed.

Closer to the farm, authorities implemented a 1.5 mile protection zone to which access is restricted and a six mile surveillance zone.

Local authorities contacted poultry owners within the restriction zone to tell them that all birds must be brought indoors.

“We are hoping that the restrictions that have been put in place to stop people moving birds, while they’re going to be difficult for poultry farmers, will stop this disease from spreading,” said Jill Korwin, assistant head of Trading Standards for Suffolk. “Poultry owners must keep their birds under cover.”

The outbreak is the first known instance of H5N1 in Britain since an infected wild swan was found in Scotland in March. Turkeys and chickens are more susceptible to H5N1 than wild birds, who can carry the virus over long distances without showing symptoms.

The European Commission said EU food and animal health experts would discuss the outbreak on Tuesday and review British measures to contain the disease.

In France, Agriculture Minister Dominique Bussereau ordered the government food safety agency to evaluate the country’s current risk level, a ministry statement said. France was hit a year ago by the deadly virus at a turkey farm in the southeast.

Experts stressed the situation did not pose a public health threat, and that eating well-cooked poultry products posed no risk. However, close contact with sick birds, such as in slaughtering or plucking, could lead to the disease being transmitted.

Dr. David Nabarro, senior UN system coordinator for avian flu and human influenza, told The Associated Press that there will be an increase in bird flu outbreaks around the world, but said the virus is unlikely to spread from the affected farm in Britain.

“From what I picked up during the last three days the UK government has instituted the proper precautions .... This should mean that (it) won’t spread out into other parts in the vicinity,” he said in an interview in Indonesia, the country worst hit by bird flu.

Last year, the H5N1 virus was discovered in countries in Africa, the Middle East, Central Asia and Europe. The World Health Organisation has warned that a repeat is possible this year, encouraging countries to remain on high alert.