Limited human-to-human transmission of bird flu may have occurred in an Indonesian family which lost seven members to the virus but there was no evidence it had mutated into an easily transmissible form, the World Health Organisation (WHO) said. The seven fatal cases in North Sumatra, the largest cluster of infections in Indonesia, have heightened fears that the virus had passed between people. These cases brought Indonesia's bird flu death toll to 32.
The WHO said although human-to-human transmission could not be ruled out, the search for a possible alternative source of exposure was continuing.
"All confirmed cases in the cluster can be directly linked to close and prolonged exposure to a patient during a phase of severe illness," the WHO said in a statement posted on its website.
"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 genetic sequencing revealed no evidence of significant mutations of the virus.
Scientists fear a global pandemic if the virus mutates and becomes easily transmissible between humans.
More than 120 people worldwide have died from bird flu since it re-emerged as a threat in 2003 -- most of them in Asia.
Indonesia has had more bird flu deaths than any other country this year. It has the world's second highest number of fatalities since 2003, after Vietnam. Nine Indonesians who were infected have survived.
