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WHO Schedules News Conference on Qinghai Visit
Recombinomics Commentary
June 27, 2005
>> WHO and FAO officials will discuss the outcome of the Qinghai mission, and take broader questions as well on the avian influenza situation in China at this time. <<
Although rumors suggest that tomorrow's press conference will not identify human cases associated with the Qinghai H5N1 bird flu outbreak, answers to broader questions may provide additional useful information.
Sequence data could help place the outbreak in the context of an evolving H5N1. Although no 2005 H5N1 sequences have been made available to the public, media reports have indicated the sequences from the Qinghai isolates from bar headed geese are similar to sequences from southeast China. Other reports have indicated southeast Asia, which would be similar to isolates in Vietnam and Thailand and raise questions about human transmission.
However, sequences related to southeast China would also be of interest. All of the H5N1 sequences at GenBank from 2004 isolates from Vietnam and Thailand are amantadine resistant. However, most sequences from China do not have those resistance markers, so the marker profile for positions 26 and 31 in the M2 gene would be of interest. The closeness to earlier sequences would also raise questions about the origin of the sequences. The initial isolates were from bar headed geese, which winter in northern India and begin to migrate to Qinghai Lake in early may. Since the geese were found dead on May 4, they were likely infected in India, since they can fly to Qinghai Lake in less than 24 hours.
A match of sequences in China would suggest that the H5N1 in China is widespread and may also be in India and Bangladesh, the winter home of bar headed geese. The data would also explain the H5N1 antibodies in Indian poultry workers. The false negatives in Vietnam raise concerns that H5N1 may be silently spreading and could already be quite widespread in India and Bangladesh. Screening with appropriate primers could provide a better read on the extent of H5N1 in Asia.
The migration of the birds in early May also coincided with a meningitis outbreak in northern India. There have been several third party reports suggesting H5N1 infections in humans may also be associated with the bar headed geese. Boxun reports in Abundant News described a much larger outbreak than was reported, including over 8000 bird deaths representing 13 species. In addition, there were reported deaths of mammals including domestic animals and humans.
The Qinhai outbreak was followed by an outbreak in Tacheng in Xinjiang province. The affected birds were domestic geese and this outbreak was followed by reports of pneumonia isolation wards at the Tacheng Hospital. Initial requests to visit Xinjiang were denied, but have since been granted. The pneumonia clinics raise additional concerns of human transmission.
There was another reported outbreak in Xinjiang, and again domestic waterfowl were involved, further supporting transmission by migrating birds.
Recently there have been rumors that local media in Qinghai carried reports of several human deaths linked to bird flu. These reports have not been confirmed, but extend the number of third party reports suggesting human transmission of H5N1 in China.
Information specifically addressing these rumors would be useful.
Media sources