The WHO says more reported bird flu cases due to vigilance, not spread.RADIO H/L:

The World Health Organisation has said that a likely increase in the number of reported cases of a strain of influenza in Hong Kong, known as bird flu, will be due to better surveillance, rather than an increase in transmission.

It said there was still no evidence of how the virus -- previously known to exist only in birds -- was spread.

But there was no need for quarantine measures or travel restrictions.

The disease has killed at least three people in Hong Kong, where the authorities have banned the import of chickens from mainland China.

From the newsroom of the BBC World Service