According to official sources in China an outbreak of H5N1 bird flu has been detected among wild birds in the remote far-western Qinghai province and in Tibet.

Apparently as many as 400 wild birds have recently been found dead in the same area as an outbreak of the H5N1 strain at the same time last year which killed thousands of birds.

The region is a wild area where few people live and no poultry are raised.

The same strain has been found in Europe, Africa and the Middle East.

Roy Wadia, a spokesman for the World Health Organisation in China, says though the outbreak is not unusual extra care needs to be taken to ensure people do not get infected.

It is reported that the governments of Qinghai and Tibet have disinfected the region where the birds were found; it appears no domestic poultry has been affected.

To date China has reported at least 18 human infections of the H5N1 strain, 12 of which have been fatal. It has also reported almost 40 outbreaks of bird flu in poultry across a dozen provinces over the past year.

The ever present fear is that the virus will mutate into a form which could pass easily among humans, potentially triggering a pandemic in which millions could die.

The outbreak has occurred on the same migratory route where another outbreak in Yushu of Qinghai was reported early this month.

According to the state media China has tightened its controls in Yushu county, about 800 km (500 miles) from the Qinghai capital Xining, where an outbreak of the H5N1 strain among wild birds was reported at the beginning of the month and at least 123 wild birds have been found dead.

Health experts say the country is particularly at risk because of its huge human population and many poor, remote areas.