China’s top epidemiologist said Tuesday that the country is closely monitoring any possible new mutation of the A/H1N1 flu virus. 28,774 confirmed cases of swine flu have been reported in 74 countries across the world, including 13,000 confirmed cases in the U.S. The disease has caused 144 deaths throughout the world, including 27 deaths in the U.S. The origin of the swine flu outbreak can be traced to Mexico, where the virus has reportedly killed and infected 108 and 6,241 people respectively (data as of June 11, 2009). Tuesday, China reported 237 infections on the mainland with no fatalities. “We are well prepared for the battle against any possible new mutation of the flu virus,” said Zeng Guang, chief epidemiologist of the Chinese Center for Disease Control and Prevention, on the sideline of a seminar in Beijing.