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H5N1 in Qinghai China Efficiently Kills Chickens
Recombinomics Commentary
May 28, 2005
>> The conflicting numbers in different announcements illuminate the need for clarification. An avian influenza virus which will kill such numbers of wild birds belonging to different species and within a
short time frame is exceptional. Let us wait for official details in China's expected notification to the OIE, particularly the number of tested birds of each species, pathological changes observed, diagnostic techniques applied and exclusion of other potential causative agents. - Mod.AS] <<
The above commentary from ProMed suggests that the mounting toll of birds found in and around Qinghai Lake Nature Reserve may have additional causes beyond H5N1 infections. However, The latest update of the May 21 report to OIE indicates that the 519 dead birds were classified as HPAI (Highly Pathogenic Avian Influenza) was based on clinical and laboratory data.
The update indicates the laboratory data was based on PCR and intravenous pathology index. The PCR test shows that the isolates have a multi-basic cleavage site in HA, a feature found in the vast majority of H5N1 isolates in Asia. However, many of the 2005 isolates in Vietnam are asymptomatic in waterfowl and to a lesser extent chickens. There have now been over 1000 bird deaths in Qinghai involving at least five species of waterfowl.
The intravenous pathology test involves infecting chickens with the virus. These data indicate that the isolates on Qinghai can also kill chickens at a high frequency.
These data suggest that the large number of bird flu deaths is due to H5N1 infection alone, because the egg grown virus can kill test chickens easily.
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