"Nothing demonstrates that the virus has mutated or recombined," Bernard Vallat, director general of the global watchdog for veterinary standards in farm trade, told reporters.

The World Health Organization (WHO) said earlier in the day that limited human-to-human transmission of bird flu may have occurred in the Indonesian family -- but that there was no evidence it had mutated into an easily transmissible form.

The OIE chief confirmed there was currently "no cause for concern", but didn't exclude a new epidemic event if further tests reveal significant changes to the genetic sequences of the virus.

More than 120 people have died from bird flu since it re-emerged as a threat in 2003, mostly in Asia.