Margaret Chan on Thursday took charge of the World Health Organization, the most prominent UN post ever filled by a Chinese national, and promptly renewed the agency's warning that the world must keep up its guard against bird flu.
Chan said there had been a lull in bird flu infections in recent months, but that cases had begun picking up again in the last few weeks.
"This H5N1 (virus strain) is causing unprecedented damage to the poultry sector, and along the way many people were infected, and more than half of these people died," Chan said. "We must not let our guard down. We must maintain our vigilance."
She said the world was gearing up to improve surveillance of the disease and rapid response to any outbreaks.
More also needed to be done against older diseases, such as malaria, she said.
"We are taking a new look at how to deal with this very tenacious killer," Chan said. "We have the tools, but we need to understand why we are not making progress." Some 3,000 children die from the disease every day, she said.
WHO also intends to press on with its campaign to eradicate polio, even though it missed its target of destroying the disease in the world by 2005 and had to set a new goal of the end of 2007, Chan said.
Chan told WHO staff that she did not foresee a major restructuring of the agency, but that she would be looking for ways to improve cooperation among different parts of the organisation.