An Indonesian who died after catching the A(H5N1) bird flu virus from his 10-year-old son has become the first confirmed case of human-to-human transmission of the disease, according to a World Health Organizationinvestigation.
The 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.
Said WHO spokesman Dick Thompson:
Yes, it is slightly altered, but in a way that viruses commonly mutate. 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 WHO and U.S. Centers for Disease Control and Preventionto document that the virus almost certainly was passed from person to person.
In previous cases where human-to-human transmission was suspected, researchers could not test samples from the patients, or the virus in the patients was the same as that in poultry in the area.
The investigation vindicates some Internet flu watchers who had disputed statements by a WHO official and the Indonesian Health Ministry soon after the family cluster was reported, saying it was possible the whole family had been infected by a barbecued pig, poultry or chicken manure.
The independent flu watchers, relying on local Indonesian news media, had argued that the pattern of dates on which different family members fell ill suggested that the virus had jumped from human to human to human.