The World Health Organization Director-General Dr. Margaret Chan said on Thursday that the H1N1 virus was stable and there was no sign yet of it mixing with other influenza viruses.
Some health officials have raised concerns that if H1N1, also known as swine flu, combined with the much deadlier H5N1 bird flu virus then the pandemic could claim many more lives.
Chan's remarks are some of the first comments by the WHO leadership since the United Nations agency declared an influenza pandemic on June 11.
Chan said the viruses needed to be closely monitored to make sure there was no mutation.
Some health officials have raised concerns that if H1N1, also known as swine flu, combined with the much deadlier H5N1 bird flu virus then the pandemic could claim many more lives.
Chan's remarks are some of the first comments by the WHO leadership since the United Nations agency declared an influenza pandemic on June 11.
Chan said the viruses needed to be closely monitored to make sure there was no mutation.