ADVERTISEMENT China says bird flu virus in humans mutating Nov 28 9:50 AM US/Eastern Email this story The H5N1 strain of bird flu seen in human cases in China has mutated as compared with strains found in human cases in Vietnam. Chinese labs have found that the genetic order of the H5N1 virus seen in humans infected in China is different from that found in humans in Vietnam, Xinhua news agency reported Monday. In China's human cases, the virus has mutated "to a certain degree," health ministry spokesman Mao Qun'an was quoted as saying. "But the mutation cannot cause human-to-human transmission of the avian flu," he noted. China this month confirmed its first three human cases of bird flu, two of which were fatal. The disease has killed more than 60 people in Asia since 2003. Health officials fear that the virus could mutate to the extent where it is easily transmitted from human-to-human, an event that could lead to a global pandemic capable of killing hundreds of millions of people.