NEW : 60 dead from a total of 13 cases of bird flu in H7N9 , authorities say . The virus is normally found in birds . China was never known to infect people until the weekend . The two deaths , both in Shanghai , takes the death toll to 13 , the Xinhua news agency said . Cases of the virus have now spread to central and northern China .
NEW : 60 dead from a total of 13 cases of bird flu in H7N9 , authorities say . The virus is normally found in birds . China was never known to infect people until the weekend . Cases of the virus have now spread to central and northern China .