ROME, June 23 — An Indonesian who died after catching the A(H5N1) bird flu virus from his 10-year-old son represents the first confirmed case of human-to-human transmission of the disease, a World Health Organization investigation of an unusual family cluster has concluded, the agency said Friday.
The W.H.O. investigators also discovered that the virus had mutated slightly when the son had the disease, although not in any way that would allow the virus to pass more readily among people.
"Yes, it is slightly altered, but in a way that viruses commonly mutate," said Dick Thompson, a spokesman for the agency in Geneva. "But that didn't make it more transmissible or cause more severe disease."
The greater importance of the slightly modified virus is that it allowed researchers from the W.H.O. and the Centers for Disease Control and Prevention in the United States to document that the virus almost certainly was passed from person to person.
Are we prepared in this county for the pandemic that's coming? All I have to say is this: remember Katrina.