The World Health Organisation has said it is concerned about the world's first probable human to human transmission of the bird flu virus.
A 26-year-old woman died last week in Thailand. She had been looking after her 11-year-old daughter in hospital.
Thai authorities said it was an isolated incident, but the WHO said it was concerned that the incident could signal the start of a wider spread of the disease.
There had been fears that the virus, which swept through much of Asia early this year, could mutate into a form that could be passed from person to person.
