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Evidence for More H5N1 Wild Bird Flu Recombination
Recombinomics Commentary
August 30, 2005
"the fact is that in the Mongolia, where the wild bird does not contact with the poultry and the man, it is possible to trace the development of epizootic disease precisely among the population of wild birds", it noted A.Shestopalov.
According to him, Russian and Mongolian virusologists will stay in the Mongolian Altai lakes to the middle of September.
It also noted that recently it returned from The zdvinskeyeo region of the Novosibirskaya Oblast, where earlier was also noted the circulation of the virus of bird influenza.
"according to our observations, among the wild bird there was also case - according to the visual estimations, its livestock is 2 - 3 times less than in the recent years", it noted A.Shestopalov.
A.Shestopalov it also reported that in the course of materials research, delivered from the experimental-production economy of the Siberian scientific research institute of poultry raising (Omsk region), pathogenic material it was not discovered.
"were carry ouied the necessary studies, in this case the chickens, which they infected by the virus chosen in Omsk birds, survived", it noted.
The machine translation above indicates Russian scientists are traveling to Mongolia to study the H5N1 outbreak in the Altai Lakes region. This is where initial isolates in Mongolia originated. Included were fatal infections in whooper swans and bar headed geese. Because this region is report. It offers the opportunity to study the H5N1 in the absence of additional infections, which may be present in domestic poultry.
Indeed, the electrophorgram submitted to OIE by Russia showed a complex pattern of H5N1 related genetic information from a wild bird. Similarly, the isolates from Qinghai Lake suggested some if not most birds had dual infections.
The above report suggest that some of the H5N1 in Omsk was not pathogenic to chickens. This is in marked contrast to the H5N1 from Qinghai lake, which killed experimental chickens within 20 hours. H5 has been reported in the past at both Chany lake in Novosibirsk, as well as Pirmorie in eastern Russia. These earlier H5's were genetically related to H5N2 from Europe. The co-circulation of H5 from Europe and Asia can lead to additional recombinants.
Dual infections lead to recombination, which was also evident in the partial sequence submitted by the Vector lab at Novosibirsk. Although the NA sequence was virtually identical to the sequences from Qingahi lake, the HA sequence had at least one polymorphisms that was absent in the Qinghai lake sequences, it present in isolates from Japan and South Korea. These data suggest the H5N1 wild bird sequences are evolving via recombination.
The latest H5N1 map shows newer outbreaks in eastern Mongolia. These birds have probably already entered China and may be causing dual infections in Primorie as well as Japan and South Korea. These dual infections can lead to additional genetic drift via recombination.
The genetic drift has already produced H5N1 wild bird sequences that are significantly different than H5N1 in Vietnam. The worldwide effort to create a pandemic vaccine has targeted a 2004 isolate from Vietnam. However, such a vaccine is unlikely to be effective against the wild bird sequences.
Collection of additional sequences from Mongolia will help determine how quickly the H5N1 is evolving. Samples have already been comfimed in Japan to be H5N1 positive. WHO is also planning a visit to Mongolia.
Pandemic vaccine efforts should be targeting multiple versions of H5N1. The H5N1 wild bird flu is clearly spreading, and the upcoming migration season may move H5N1 worldwide, increasing the likelihood of additional recombinations leading to efficient human-to-human transmission.
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