Two young girls have contracted a strain of Avian flu which has previously only been found in chickens and ducks.

The two girls, aged one and four, developed flu-like symptons last month.

Initial tests suggested the presence of an unusual virus but further tests in the United States identified it as H9N2 - an avian virus never before found in humans.

Both girls have since recovered, but health officials do not know how the children, who live in different parts of Hong Kong, came to contract the virus.

It is the first time local people have been infected with a bird flu virus since an outbreak in 1997, which killed six people and led to the slaughter of Hong Kong's 1.5 million chickens.

New controls

The news comes less than two weeks after government officials announced the discovery of a new strain of a different avian virus - H5N1 - in a consignment of live ducks and geese in a local market.

That was the first instance of avian flu found in Hong Kong since tough new controls were introduced last year.

These include random testing, stricter hygiene procedures and the segregation of chickens from ducks and geese.

Ducks and geese are natural carriers of many avian flu viruses, but it is when they pass the infection to chickens that the risk to people becomes much greater.

Most of Hong Kong's live poultry is imported from mainland China.

There have been unconfirmed reports that the new virus contracted by the children in Hong Kong has already infected people in China's southern provinces, but those cases have not been independently verified.