Asia 'not hiding bird flu cases'

A mandarin duck is vaccinated against bird flu in China

There is no evidence of hidden cases of bird flu in people in South-East Asia, British scientists have stated.

A team from the Medical Research Council went to China and Vietnam to investigate if there were more cases in humans than had been revealed.

The deadly H5N1 strain of bird flu has infected 122 people across South East Asia, and killed 62.

But there have been no human cases reported from China, despite numerous outbreaks of the virus in birds.

I don't think the people known to have been infected are the tip of the iceberg Sir John Skehel, Medical Research Council See which countries have been affected by bird flu

This had led to fears that cases were going unreported.

But Sir John Skehel, director of the MRC's National Institute for Medical Research, and one of the researchers who went on the fact finding mission, said he had been persuaded that this was not the case.

"I don't think the people known to have been infected are the tip of the iceberg. It is a relief, because avian flu is in over 60 provinces in China."

The team said their findings backed up previous suggestions that it is relatively difficult for this strain of bird flu to pass from birds to humans.

'Small clusters'

However, scientists fear that if the strain mutates or combines with another virus to become easily transmissible between people, it could trigger a global pandemic.

Sir John said that in south-east Asia, health workers were highly exposed to people infected with H5N1.

He added: "Many of the cases initially were received without any special care being taken in terms of gloves or masks, and still there was no transmission."

He said there had been one recorded case of a nurse who became infected and died.

"We reinforced the idea that the cases so far have resulted from close contact with poultry.

"There have been some small clusters of cases that could lead to the suggestion that there was human-to-human transmission, but the numbers are so small that it's not convincing."

He said China had 20% of the world's chickens, and more than 70% of its domestic ducks.

Experts plan to cull birds in a 3km area of any bird flu outbreak, but vaccinate birds outside this zone.

In the UK and other countries, the plan is to kill all birds in an affected area rather than take a risk with vaccines.

Thousands of birds have already been exterminated following outbreaks in Romania and Turkey.

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