Bird Flu Confirmed on Czech Turkey Farm
Recombinomics Commentary
June 20, 2007
Hundreds of turkeys at a farm in eastern Czech Republic tested positive for the bird flu virus, an official said Wednesday.
Semerad said that of the 6,000 turkeys at the farm in Tisova, 100 kilometers (62 miles) east of Prague, 1,800 already have died.
The above comments suggest H5N1 has re-emerged in western Europe. Although the serotype has not yet been confirmed, the large number of deaths suggests the cause will be Qinghai (Clade 2.2) H5N1.
Ironically, minutes before the announcement, western Europe was declared to be bird free at the Options for the Control of Influenza VI conference in Toronto. Ian Brown from the Veterinary Laboratories Agency (Weybridge) gave a review of H5N1 in Europe. He noted that the limited reporting of H5N1 in 2007 was from areas that had H5N1 in 2006, and since the regional markers re-appeared, the new outbreaks were due to a failure to stamp out the H5N1 from last year. Similarly, Ilaria Capu from the Instituto Zooprofilattico Spermentale della Venezi cited the negative data of live wild bird tests in Europe and Africa to declare wild birds H5N1 free.
However, there is little data to support such interpretations. Russia is still reporting H5N1 in live wild birds, and there is little reason to expect the H5N1 in long range migratory birds to disappear. Such hopes and dreams are often repeated, but the above data on the turkeys in the Czech Republic suggest that lack of detection of H5N1 in live birds is due to the lack of sensitivity in the surveillance assays.
Last year H5N1 was detected in over 700 samples from Europe. The vast majority of the positive samples were from dead wild birds. None of the positives were from live wild birds. Last year, the deaths may have been linked to a harsh winter. The milder winter this year may have lead to a decrease in H5N1 detection, rather than a decrease in H5N1 in live wild birds.
The serotype of the avian influenza in the dead turkeys will be of interest. H5N1 is likely, as is a wild bird source. Last year H5N1 was found in wild birds in the Czech Republic. The sequence of the public H5N1 is similar to H5N1 from Italy and Germany. Like last year, H5N1 is likely to be in wild birds throughout western Europe, but has remained below the detection level.
Improvement of surveillance and quick release of sequences from the latest outbreak would be useful.
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