Results, which could prove the existence of a new strain of bird flu are being waited for in Hong Kong, following a number of deaths.
The virus is normally transferred from birds to human beings but scientists are worried it could now be passing from person to person - with potentially devastating consequences.
Five years ago, the world was put on high alert when six people in Hong Kong were killed by bird flu. Nearly a million chickens were slaughtered in an attempt to stop the spread of the virus.
If the Hong Kong strain were to spread it would be the fourth major flu outbreak in the province in the past five years. Each one has led to massive bird culls.
Hong Kong imports 80,000 chickens from China every day.
