Hong Kong has to be vigilant against the new H7N9 strain of avian flu later this year when migratory birds head south from northern parts of China for the winter, says a Hong Kong microbiologist. University of Hong Kong microbiologist Professor Yuen Kwok-yung said on Friday he believed a large number of wild birds had already contracted the virus in eastern China, where all the cases of human H7N9 had occurred. Some of them were migratory birds, which were now heading to northern parts of the mainland for summer but would return south to the Pearl River Delta for winter, he said. “This is when Hong Kong’s wild birds and poultry may get infected,” he said at a press conference on Friday afternoon. The H7N9 avian flu has killed 10 people in Shanghai and several provinces in eastern China since authorities announced the first infection about two weeks ago. So far, 38 human cases have been confirmed. Yuen, who earlier visited Shanghai and met health officials to learn more about the flu outbreak, said analysis of the virus’ genes suggested the chance of human-to-human transmission was low. He also said southern China and Hong Kong were now largely safe with no traces of the new bird flu virus reported so far. But he urged authorities and the public to remain vigilant. Dr Owen Tsang Tak-yin, a Hospital Authority official, said Hong Kong had 18 million doses of Tamiflu, a drug that has proven effective in the treatment of bird flu. View H7N9 map in a larger map Click on each balloon for more information on individual patients infected: blue, patients infected with the H7N9 virus under treatment; red, those infected with H7N9 who have died; yellow, those who have fully recovered; and pink, those infected with the Influenza A H1N1 virus.