The World Health Organizations chief representative in China, Michael O’Leary, said that the actual death toll on the Chinese mainland from the H1N1 "swine flu" virus is likely much higher than reported, state media reported. O’Leary made the warning yesterday after China reported its third official H1N1 death. O’Leary said that many deaths around the world are not being scrutinized with lab tests, which means most H1N1 deaths are likely to go unrecorded. The Hong Kong Health Department has estimated that the number of undiagnosed flu cases could be 25 times higher than the official number. Zeng Guang, chief epidemiologist for the Chinese Center for Disease Control and Prevention said that lab limitations mean that some flu deaths may go undetected. The mainland has reported a new surge of flu cases and three deaths this month as H1N1 begins to resurge around the world. Experts expect the western regions of China to be hardest hit due to their relatively undeveloped health infrastructure.