WHO stressed the virus was not yet spreading easily among people -- a
necessary first step toward a feared pandemic.
"To date, the investigation has found no evidence of spread within the
general community and no evidence that efficient human-to-human transmission has
occurred," the WHO said.
And samples from the victims have not shown any big genetic changes.
"Sequencing of all eight gene segments found no evidence of genetic
reassortment with human or pig influenza viruses and no evidence of significant
mutations," the WHO statement read.
"The human viruses from this cluster are genetically similar to viruses
isolated from poultry in North Sumatra during a previous outbreak."
Several health experts have expressed concern about how long it has taken to
get information about the outbreak in Sumatra and said it shows that if H5N1 did
evolve into a pandemic form, there would be little chance of stopping it.
"It does shake your confidence in the fire blanket approach," Dr. Eric Toner
of the Center for Biosecurity at the University of Pittsburgh Medical Center
said in an interview.
A 'fire blanket' approach would involve using drugs, isolation and quarantine
to stop an early outbreak of human-to-human spread of the virus.
WHO is trying to encourage countries to report suspected bird flu cases
quickly. But there are fears that some countries may try to cover up cases, in
order to deal with them quietly.
WHO and other agencies have been on alert after an Iranian medical official
told Reuters on Monday that a 41-year-old man and his 26-year-old sister from
the northwestern city of Kermanshah had tested positive for bird flu.
Health Minister Kamran Lankarani denied this although international health
officials are still investigating.
"Fortunately, these two cases were negative for avian flu. There is no
confirmed case until now," Lankarani told Reuters at the WHO annual meeting in
Geneva.
The two siblings were among five members of a family who became sick and the
other three remain in the hospital.
A Japanese currency trader said the WHO report triggered some selling of yen
in early Asian trading, which weighed on Taiwan's currency. The Australian
dollar was also hurt by the report, and Australian bond futures reached
four-week highs.
Markets are sensitive to bird flu reports as a pandemic would probably hurt
consumption across the globe, slowing growth and putting downward pressure on
interest rates.
