Geneva ? Tackling issues from bioterrorism to AIDS, malaria and drug patents, the top U.N. health policy body begins its weeklong annual meeting today.

The World Health Assembly, which brings together the 191 nations of the World Health Organization, also is set to hold politically charged debates on Taiwan’s bid for observer status and the health effects of the Mideast crisis.

The assembly will likely decide whether to drop a deadline for destroying stocks of the smallpox virus, held at top security laboratories in the United States and Russia.

Acting on fears of bioterrorism in the wake of the Sept. 11 attacks and worldwide anthrax scares, the WHO in January reversed a long-standing order for the destruction of the stocks by the end of the year and recommended they be retained for research into new vaccines or treatment.

David Nabarro, executive director of WHO, said the bioterrorist threat was an “evolving subject.”

“There has to be attention paid to the outside chance of a substantial use of biological weapons,” he said. “Member states have concerns about the use of smallpox as a weapon and have made it clear they do not think the time for destruction has been reached.”

Smallpox used to kill 3 million to 4 million people per year and left millions more hideously scarred and blind. It was declared eradicated in 1979 after a massive WHO-spearheaded campaign.

Although international teams carry out regular checks of the facilities to ensure maximum security standards, there have been long-standing fears that samples may have found their way into the hands of nations such as North Korea or Iraq.

Taiwan has attempted for the past five years to get observer status at WHO, but has failed because of rival China’s objections. Last year Beijing rallied its allies at the World Health Assembly to stop the Taiwanese application being included on the agenda.

Taiwan and China separated amid a civil war in 1949. China claims self-ruled Taiwan is a breakaway province with no right to representation in international organizations.

Nabarro said the island “is not an entity that has relations of any kind with WHO,” but that officials from Taiwan can attend the assembly “as members of the public.”

In the past Taiwan has won backing from the United States and several European nations for its bid for observer status. In March, the European parliament passed a nonbinding resolution urging European Union nations to support Taiwan at this year’s meeting. Last month President Bush signed a bill also giving U.S. backing to Taiwan.

The situation in the Middle East will be the subject of much debate, as it has been within almost every U.N. body in recent months.

Last year’s assembly passed a resolution criticizing Israel for the health situation facing Palestinians, citing “excessive force” during military operations.

It also voiced alarm that Israel’s closure of Palestinian areas for security reasons had damaged programs such as immunization, water safety, insect control, and mother and child health.

The resolution was sponsored by Arab and European nations. But Israel, the United States, Canada and several Latin American countries opposed it, all citing fears of unnecessary politicization of the U.N. health body.

Delegates at the World Health Assembly, which ends Friday, also are expected to discuss other health issues ranging from the right of poor countries to relax drug patent rules in the fight against epidemics to the link between diet and health.