The Chinese Center for Disease Control and Prevention yesterday handed over human strains of the H5N1 bird flu to the World Health Organization for study.

Two strains of bird flu isolated from human infections were forwarded to Dr Shigeru Omi, WHO western Pacific regional director, by Wang Yu, director of the Chinese CDC. Wang also provided virus information on Chinese human cases.

Sent for further research, the strains will help trace the virus' mutation and develop anti-retroviral drugs. It is a major contribution made by China to the global fight against the epidemic, said Omi.

Omi said good collaboration in the international community will be crucial in dealing with the immense challenge posed by bird flu, and China, as one of the centers of the global fight, can play an important role.

Chinese experts will join in the WHO's research of these isolates.

China has been completely open in providing information on bird flu cases, Elias Zerhouni, director of the US National Institutes of Health, said yesterday.

Zerhouni told a Beijing news conference that there was a stark contrast between China's openness about bird flu and its dealing with the outbreak of severe acute respiratory syndrome three years ago.

"China is definitely cooperative and transparent in controlling bird flu and is ready to exchange virus samples with the World Health Organization and other partners so as to track the genetic changes of the virus," Zerhouni said.

"Tracking changes in samples from human cases is key to developing a vaccine," Zerhouni said.

Now the United States and the Chinese Health and Agriculture ministries are cooperating to build the ability to detect and diagnose the virus and train experts, he said.

"We are going to collaborate on multiple levels," he said.

China has announced six human cases of bird flu since November 16, including two fatalities, according to the Ministry of Health.

Lab tests show that the genotype of H5N1 in human bird flu infections in China is different from that in Vietnam, indicating that the virus has mutated.

An international meeting will be held in Beijing to raise funds for bird flu prevention and control from January 17 to 18, Foreign Ministry spokesman Qin Gang announced yesterday.