Concern after bird flu 'passes from father to daughter'
7 August 2013 Last updated at 01:52 BST
Researchers have reported the first case of human-to-human transmission of the new bird flu that has emerged in China.
The British Medical Journal said a 32-year-old woman was infected after caring for her father.
Until now there had been no evidence of anyone catching the H7N9 virus other than after direct contact with birds.
Emily Thomas reports.