A dead Grey Heron was picked up from Lok Ma Chau on Monday, 1 November 2004 and has since been identified as carrying the H5N1 virus.

Generally, the avian influenza virus (H5N1) in wild birds is of low pathogenicity. Once the virus enters the domestic poultry population, it then requires several months of circulation amongst the domestic poultry in order to mutate from a form causing very mild disease to a form causing highly pathogenic disease, with a mortality approaching 100% amongst the domestic poultry. (http://www.who.int/csr/don/2004_10_29/en/;29 Oct 04).

"Wild birds are known to carry the H5N1 avian influenza virus so this finding is of no surprise. The fact that there were isolated cases of H5N1 outbreaks in SE Asia this summer indicates that the virus is endemic in the poultry population, and does not now need migratory birds to help its spread. This is because of the commercial movement of poultry from the countryside to cities, from cities to cities and from countries to countries," said Dr Lew Young, Mai Po Reserve Manager, WWF Hong Kong .

Apart from wild birds and poultry, the H5 virus has now also been isolated from domestic ducks, pigs, cats and tigers.

"In Hong Kong, there is little health risk to the public of going out to the countryside or areas where there are wild birds. However, the public should take care of their personal hygiene at all times, such as trying not to touch areas that may have bird droppings. If so, then they should wipe their hands with hand sanitizers that are available commercially," continued Dr Lew Young .