H5N1 Sequences in West Bengal Similar to Uva Lake
Recombinomics Commentary 16:58
January 29, 2008
Health Secretary Naresh Dayal said the virus detected in West Bengal was somewhat similar to those found in Maharashtra in 2006, but not like those found from Manipur.
'We want to trace its origin,' Dayal too said, adding that migratory birds could not be wished away as the source of the outbreak in West Bengal.
The above comments on sequences from West Bengal are not a surprise. Sequences from the 2006 outbreak in India have been released and they are clade 2.2.3, which were also seen in Afghanistan, Azerbaijan, and western Russia.
In the summer of 2006 there was a massive outbreak of H5N1 at Uva Lake. The number of dead wild birds was on a par with the outbreak a year earlier at Qinghai Lake. Uva Lake is the largest lake in Mongolia and is just south of the Siberian border at Tyva in Russia. H5N1 sequences from ducks and grebes in Russian as well as a whooper swan and common goldeneye were published. These sequences formed a separate branch of a phylogenetic tree.
At the end of 2006, the sequences were found in the outbreak in South Korea. In early 2007, they were only reported for Kuwait. However, beginning in the summer of 2007, the Uva Lake strain was found throughout Europe. In the summer it was in the Czech Republic, Germany, and France. By the end of 2007 it had been reported in Krasnodar, England in two separate outbreaks, Poland, Romania, and northeast Germany. In these locations, the clade 2.2.1 and 2.2.2 which had been seen in 2006 were largely replaced by clade 2.2.3.
Therefore, based on the history of H5N1 in India and south Asia, sequences related to the Uva Lake strain would be expected in Bangladesh, West Bengal, and Pakistan. Similarly, the recently reported outbreak in southern Tibet would also be expected to be related (see satellite map here and here).
Release of all of the recent sequences, as well as sequences from early 2007, would be useful.
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