A six-year-old Indonesian boy died from bird flu over the weekend in a local hospital, bringing the country's death toll from the disease to 81, a local news agency reported Monday.

Tests confirmed that hundreds of turkeys in Eastern Czech Republic died of the H5N1 bird flu virus. It was the first time the virus was detected among poultry in the Czech Republic, said Zbynek Semerad, a spokesman for the Czech veterinary authority.

Amid heightened concern over a possible epidemic of bird flu in humans, scientists in the United States and Taiwan are reporting critical new insights into the architecture of a key enzyme in the H5N1 avian influenza virus that enables the virus to spread.

Starting with blood of patients who survived a bout of avian flu (infection with the H5N1 strain), Cameron Simmons (of the Oxford University Clinical Research Unit at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam) and colleagues generated neutralizing human monoclonal antibodies and show that they can halt viral growth in mice deliberately infected with H5N1 virus.

Two of three promised samples of bird flu in China have arrived in the U.S., the WHO said. The samples are the first sent by Beijing in a year. The sample updates of the H5N1 virus from China's Health Ministry are awaiting customs clearance, said Joanna Brent, a spokeswoman for WHO's Beijing office.

The Indonesian Health Minister says her country has resumed sharing samples of the H5N1 bird flu virus with the World Health Organisation (WHO) after a five-month gap.

Indonesian health officials say they are hopeful a new international agreement will be reached next week over the sharing of bird flu samples for vaccine research. Chad Bouchard reports from Jakarta, where Indonesia's 75th human death from bird flu has just been announced.

The World Health Organization has conducted a test of their ability to avert a bird-flu pandemic. Monday's drill involved officials at the WHO's Western Pacific regional headquarters in Manila talking by phone with counterparts in Cambodia, Singapore, Indonesia, and Japan.