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China Withholds Key H5N1 Bird Flu Data
July 20, 2005
Authorities also haven't responded to a WHO request to be allowed to visit the Xinjiang region in China's northwest, where there have been reports of a bird flu outbreak along the border with Kazakhstan, said Roy Wadia, a spokesman for WHO's Beijing office.
Chinese authorities have yet to release samples gathered in the western province of Qinghai, where at least 6,000 migratory birds have died, Wadia said.
"It would be useful if information on the virus was shared with the international agencies concerning bird flu, or if it were deposited at gene banks as per the usual procedures in these cases," Wadia said.
China's Ministry of Agriculture didn't immediately respond Wednesday to requests for comment.
China's failure to respond to foreign appeals for cooperation has prompted fears that the outbreak might be bigger and more dangerous than reported.
The above comments add considerable weight to concerns that there is a raging human pandemic in China. China has been the epicenter of the unprecedented H5N1 outbreak in 2004. H5N1 was reported throughout China and most adjacent countries. The reported human cases were in Vietnam and Thailand. In 2005 the human cases were initially concentrated in Vietnam and Cambodia.
However, the demographics of the outbreak in Vietnam suggested a less lethal but more transmissible variant was affecting northern Vietnam. Although these cases had been laboratory confirmed, WHO refused to acknowledge the widespread human-to-human transmission. The first sequences of 2005 were recently made public, and these new sequences clearly show a China connection, with sequences found in Guangdong and Yunnan province. Today fatal human H5N1 was confirmed in Indonesia in suburban Jakarta, where H5N1 was also detected in asymptomatic swine. The swine sequences also pointed toward a Yunnan origin.
The sequences of the H5N1 provide valuable clues on the origin of infections. A large database was generated using 2004 isolates and additional 2005 isolates have been deposited at GenBank, although two weeks after publication, GenBank has still not released these sequences.
The description of the sequences however, has been published and they also show links to earlier sequences from Shantou and Hong Kong. The Nature paper also described 2005 H5N1 sequences from Yunnan, Hunan, and Fujian Province in addition to Shantou in Guangdong Provicince. The Qinghai sequences also have a polymorphism in PB2 (E627K), which had previously been limited to human flu isolates. The presence in H5N1 was limited to brain isolates from experimental mice, or severe, usually fatal, cases in humans, dating back to the 1997 outbreak.
The H5N1 in Qinghai is unusually severe in migratory birds, which is why it is critical to obtain additional sequence information on the birds before they disperse throughout Asia and Europe. These sequences can help identify the genetic changes, which are required to produce more specific probes for detecting H5N1 and designing more specific vaccines.
Boxun reports indicate the birds at Qinghai Lake are infected with several versions of H5N1, which leads to new reassortants and recombinants. The Qinghai isolates are already reassortants, with three genes related to Shantou isolates and five related to a Hong Kong isolate. The E627K indicates they are also recombinants and dual infections will generate new recombinants.
The withholding of the sequence data is an ominous sign. Boxun reports indicate China has an active avian influenza program and will certainly collect samples and sequences from Qinghai lake, in addition to the sequences from the Xinjiang outbreaks. Failure to share this information adds to speculation of a widespread cover-up of human cases. Boxun reports detailed human cases in Qinghai and the description of the 10 strains indicates 7 infect humans.
China has never reported a human H5N1 case although fatal human cases in Vietnam, Thailand, Cambodia, and Indonesia all have genetic links to China.
It appears increasingly likely that an unreported flu pandemic is well underway in China.