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Sixth Recent H5N1Wild Bird Flu Outbreak In Xinjiang
Recombinomics Commentary
November 23, 2005
Miquan city in the western province of Xinjiang reported 2,604 poultry died on Nov. 15, the Ministry of Agriculture said in a statement on its Web site today.
The above report of yet another outbreak of H5N1 in Xinjiang Province highlights a failure to control the infections there in spite of repeated vaccination campaigns. The initial report of H5N1 in Xinjiang province was for a June 1 outbreak in Tacheng. This outbreak followed the May outbreak in Qingahi, which touched off a major vaccine program for Qinghai, Xinjiang, and Tibet regions. On June 10 there was another outbreak in Xinjiang in Changji just northwest of the capital, Urumqi (see June map).
The two June outbreaks were under the migratory bird flight path from Qinghai Lake to Chany Lake in Novosibirsk, Russia. The July outbreaks (see July map) provided convincing evidence that H5N1 was being transported and transmitted by migratory birds.
The November 9 outbreaks in the Beidalu and Anning regions of Urumqi signaled a return of the migratory birds from Russia and Kazakhstan. This was followed by November 10 outbreaks in Hetian City, including the Gujianbage section. Another outbreak began on November 12 in the big bay region of Urumqi followed by nearby outbreaks in Miquan on November 15 and Dabancheng on November 16. Thus, the reported outbreaks in Xinjiang have been reported at a rate of one per day for the past week.
The clustering of these outbreaks in Xinjiang in spite of major vaccination efforts highlights the difficulties of controlling H5N1 infections, especially when associated with migratory birds. Similar difficulties were encountered in Liaoning Province where there have been repeated outbreaks and boxun reports indicated 77 people have died from H5N1 infections.
Official reports have described a geographical cluster if H5N1 cases and deaths in Anhui and Hunan provinces (see map).
These clusters of cases are cause for concern because prior clusters of H5N1 cases have peaked later in the year. This season the wild birds have the PB2 mutation E627K which is associated with increased virulence in mammals. In addition, swan isolates from Mongolia have a novel HA cleavage site, which may be related to the concentration of cases in humans and birds in eastern China.
The increasingly frequent of reports out of China at this early date, in association with the migration of birds with novel H5N1 polymorphisms is cause for concern.
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