Hong Kong's experience in fighting bird flu and Sars is a model for the world in preparing for a possible flu pandemic, the World Health Organisation's top official in infectious diseases said. Margaret Chan Fung Fu-chun, the WHO's director of infectious disease surveillance and response and Hong Kong's former director of health, said that measures put in place in the city after the 1997 bird flu outbreak had proved a success. Those include the H5N1 virus surveillance programme in Hong Kong chicken farms and live chickens imported from the mainland, segregation of live chickens from water fowl in both wholesale and retails outlets and improvement in market hygiene. Water fowl are natural carriers of the avian influenza. Hong Kong was the first place in the world to report human infections of the H5N1 virus. Eighteen people were infected during the 1997 outbreak and six died. Dr Chan, who was at the helm in handling the outbreak, said: 'Some people had complained against those measures for causing them inconvenience, but as time goes on, these measures have been proven a success. 'While Southeast Asia is now troubled by bird flu, Hong Kong is still very safe. 'All these measures become valuable experience being shared with the world.' The World Health Organisation has warned that if the H5N1 bird flu virus began to spread between humans, it could end up killing up to 150 million people. Dr Chan said the risk of a flu pandemic was great. The latest bird flu outbreak infected 110 people in the past two years, with more than half of them dying. Dr Chan said the high mortality rate, a large range of animals and poultry infected and the spreading of the virus from Southeast Asia to Russia and northern mainland provinces were causes for concern. Scientists from the US Centre for Disease Control reported last week that colleagues had resurrected the extinct flu virus responsible for the 1918 'Spanish flu' pandemic that killed 50 million people and identified it as a strain of bird flu. The scientists recreated the virus after exhuming the body of a female victim, buried for 87 years in the permafrost of Alaska, and extracting infected lung tissue. Dr Chan said this finding was an extraordinary achievement and helped the world to understand more about the mysterious virus. She warned that complacency in personal hygiene was also a risk. 'For example, in some places people cook chickens well, but they have a habit of mixing chicken blood into other food.'