Life / Health

It is impossible to predict the evolution of China's human H7N9 bird flu outbreak as researchers are still trying to understand the source of human transmission, the head of the World Health Organisation said Monday.Duration: 00:58

It is impossible to predict the evolution of China's human H7N9 bird flu outbreak as researchers are still trying to understand the source of human transmission, the head of the World Health Organisation said Monday.Duration: 00:58