LAST month, eight members of a family in Sumatra fell ill with H5N1 bird flu. Seven died. Chillingly, all but one appears to have caught the virus from another family member, making this the biggest human cluster yet. It is also the first known case in which H5N1 has spread from one person to another, and then another.
The family tragedy seems to have resulted from crowded sleeping arrangements, and the World Health Organization says there is as yet no sign that H5N1 has evolved the ability to spread easily among people. But virologists remain convinced that the virus will…
