Bird flu hits the UK and the U.S.

Authorities in Britain say there has been an outbreak of bird flu on a farm in Oxfordshire.

Veterinary officials say chickens on a farm near Banbury have tested positive for bird flu, and all birds on the farm are being slaughtered.

The birds apparently have the H7 strain of the disease, rather than highly virulent H5N1 strain which poses a greater threat to humans.

Tests currently being conducted will determine just how virulent the H7 strain is and in the meantime a temporary inner control zone of 3km has been set up around the farm along with a 10km outer zone.

Poultry keepers are being urged to be extremely vigilant, practice the highest levels of biosecurity and report any suspicions of disease to their local animal health office immediately.

The Department for Environment, Food and Rural Affairs (DEFRA) says within the inner zone, all kept birds must be isolated from contact with wild birds.

Bird gatherings and movements are also banned within the whole zone, along with the movement of some products.

Those who might have been in contact with the infected birds are being monitored and offered guidance and preventative medication.

However the risk to human health from H7 avian influenza is low and the outbreak poses no safety implications for the human food chain.

Experts say properly cooked poultry and poultry products are safe to eat and the virus, while it is contracted by close contact with infected birds, is not contracted by eating food.

There have been several outbreaks of bird flu in the UK, the most recent in January this year, when the H5N1 strain was confirmed in 11 wild birds in Dorset.

In the United States officials say all 15,000 chickens exposed to a strain of the bird flu virus at a farm in northwest Arkansas have been killed and buried.

The birds had tested positive for antibodies of H7N3, a less virulent strain of the virus.

To date the H5N1 bird-flu virus has killed 240 people worldwide and millions of birds have been killed by it or culled because of it.

Experts fear the virus will ultimately mutate into a form which spreads easily among people and trigger a pandemic.