China announces bird flu outbreak

Scientists fear bird flu could mutate into a deadly human flu

Chinese officials say a new outbreak of a strain of avian flu virus deadly to humans has been detected in the eastern province of Anhui.

It comes four months after China declared itself free of the disease.

Health officials say they have isolated a chicken farm in Chaohu city, and killed or vaccinated all poultry within a radius of 5km (3 miles).

Avian flu has also been confirmed in Vietnam in recent days, and Thailand is investigating a possible outbreak.

China's national avian flu reference laboratory says its latest case is an example of the H5N1 strain.

It has been reported to the UN's health authorities.

Millions culled

A deadly strain of avian flu swept through Asia earlier this year, killing or forcing the authorities to cull tens of millions of birds.

The disease also spread to humans, causing the deaths of up to 24 people in Vietnam and Thailand.

Both countries have also been on renewed alert over the disease.

In Thailand, tests are being carried out after hundreds of chickens died at a farm in the central province of Ayutthaya.

"We are investigating this case because the death of the chickens on the farm is unusual. There is a possibility that it could have been caused by the bird flu virus," said the head of the livestock department, Limlaemthong.

"We have sent samples for lab testing. The result is due within days," he told Reuters news agency.

Small outbreaks of avian flu also have been reported in neighbouring Vietnam in recent months.

Scientists fear that at some point the deadly strain of the virus will mutate in a way which enables it to transmit from person to person, which could spark a major epidemic.