Nine new Sars cases yesterday, but it wants to see fewer than five a day The World Health Organisation has set out three criteria that Hong Kong must meet to have the travel advisory imposed against it as a result of the Sars outbreak lifted, stressing that the number of new cases must be fewer than five for at least three consecutive days. The requirement concerning new cases also involved the number of patients receiving treatment in Hong Kong hospitals being reduced to 60. The WHO stipulated two other prerequisites. Firstly, Hong Kong must have stopped spreading the virus to other nations - something that has not happened for two or three weeks already. Secondly, the mode of transmission must be understood in each case. While Hong Kong now knows the target it must aim for, a spokesman for the WHO separately warned that Hong Kong could find itself in trouble again if the outbreak on the mainland is not brought under control. 'China is the real danger,'' said Peter Cordingley, a spokesman for the WHO regional office in Manila, expressing concern that the outbreak in Hong Kong may be reignited by cross-border travel. The announcement of the criteria came after a teleconference between Secretary for Health, Welfare and Food Yeoh Eng-kiong and WHO executive director of communicable disease David Heymann yesterday. Dr Yeoh said the WHO applauded Hong Kong's 'heroic' efforts in containing Sars. The WHO emphasised, however, that the daily increase in new cases was the most important of the conditions. In general, a lifting of the travel advisory for an area depends on there being no new case for 20 days. But Dr Yeoh said the WHO appreciated the fact that it was difficult for Hong Kong to achieve the zero-case target. A spokesman for the Health, Welfare and Food Department added that the WHO said in addition to the three-day requirement, there must also be a gradual and stable decline in the daily number of new cases for 20 days. 'It doesn't help if we get 80 cases one day and then no case the day after,'' Dr Yeoh said. The daily number of new Sars cases has been in gradual decline in the past five days, with single-digits reported since Sunday. There were nine new cases yesterday, bringing the total number of infections to 1,646. A further six patients died, raising the death toll to 193. The number of patients still receiving treatment in hospital is 495. The WHO imposed the unprecedented warning for travellers not to visit Hong Kong on April 2 at the height of the outbreak of severe acute respiratory syndrome. Travel advisories were also subsequently issued against Beijing, Guangdong and Shanxi provinces. An advisory against Toronto was lifted on April 29 after a Canadian government protest. Dr Yeoh, who declined to predict when the advisory would be lifted, said the WHO also wanted the number of 'active cases'' under hospital treatment in Hong Kong to be reduced to below 60. THE THREE STEPS New cases have to fall below five a day, and active cases to 60 No exports of cases Mode of transmission should be understood