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China Offers to Share H5N1 Sequence Data
August 18, 2005
In response, an official at the Chinese Ministry of Health said yesterday that discussions are being held with international health officials about how best to share those samples with foreign researchers, who for years have complained of an opaque bureaucracy less interested in advancing science and guarding public health than in protecting itself.
"Experts including Chinese and international scientists are talking about how and in which way to share the genetic samples through the Internet, conference calls and email," said Xing Jun, a director at the Ministry of Health. "It's under way."
The World Health Organization, which confirmed the talks, has recently called on China to share strains of the bird-flu virus so scientists can compare them with those found elsewhere in the region, to better understand how the virus may be evolving. So far, those strains haven't been released. The health arm of the United Nations made a similar request with regard to the pig-borne disease earlier this week.
Negotiations on sharing sequences data are a step in the right direction. The need for such data has been clearly demonstrated by the rapid advance of H5N1 across Europe (see map). H5N1 is evolving and dramatically expanding its geographical range. Since the evolution is driven by recombination, the genetic sequences not only show where the virus has been, but where it is going.
The sequences from Qinghai Lake contained European sequences as well as sequences for the Middle East. Thus, it is not surprising that the current expansion is retracing well established migration routes. These data can be used to design new vaccines. The current pandemic vaccine being developed worldwide is directed against a 2004 strain from Vietnam. The differences between 2004 H5N1 from Vietnam and 2005 H5N1 from wild birds are significant, and the existing pandemic vaccine is unlikely to offer protection against the strain sweeping across Western Asia and entering Europe.
The initial data from Novosibirsk reveals some additional changes because the H5N1 continues to evolve. At Qinghai Lake the virus was most frequently detected in bar headed geese followed by black and brown headed gulls. Sequences from all three species were similar, but there were signs of dual infections in the isolates form the 12 birds sampled, suggesting additional evolution. This evolution was evident in the Novisbirsk data also.
Similarly, it is likely that the isolates from Tibet will also be somewhat different and be more representative of the H5N1 entering India and Bangladesh. Although neither country has ever reported H5N1 in birds or people, there is little doubt that H5N1 is in the countries and eventually such infections will be reported. The H5N1 may in fact be associated with meningitis cases in northern Indian that clustered when the bar headed geese left India for Qinghai Lake and now there are new cases in India as the bar headed geese return. It seems likely that at some point the people and/or birds will actually be tested for H5N1 with a reliable test. The sequences in Tibet can also be used as a positive control to validate the testing in India, which has never reported an H5N1 positive, although poultry workers have antibodies to H5N1.
Similarly, the isolates from Mongolia can be used to predict new infections to the east. Boxun is reporting large numbers of poultry deaths in northeast China, but there has been no reports of testing of these dead birds.
The rapid geographic spread of H5N1 offers a unique opportunity o view the H5N1 evolution. The data should make it abundantly clear that a serious vaccine effort is required, and targeting a single isolate with limited resources is hazardous to the world's health.