H5N1 in Asymptomatic Swan in Germany
Recombinomics Commentary
July 29, 2007
With 58 black neck divers as well as Blessralle, sea gull and hood diver H5N1 on Thueringer side was proven. In Saxonia anhaltinischem area were positively confirmed 212 black neck divers, Blessralle, two sea gulls, seven hood divers, dwarf divers and board duck.
The pair of parents killed later, which was for the previous year on the pond, there wintered, exhibited outwardly no disease symptoms. While the male animal did not carry the virus in itself, that was strongly infected apparently just as little ill female animal.
The above translation describes the increasing number of H5N1 positive birds at Kelbra Lake in Thuringia and Saxony-Anhalt as well as a positive asymptomic swan in Ebeleben (see satellite map) southwest of Kelbra Lake.
Although the confirmation of H5N1 positive birds from Kelbra Lake has slowed, the number of confirmed species continues to rise. At Kelbra Lake alone, confirmed positives include 270 black necked grebes, 8 great crested grebes, 3 seagulls, 2 coots. 1 little grebe, and 1 pochard. These are in addition to confirmed positives at multiple additional locations in Thuringia and Saxony was well as Nurembrg in Bavaria.
The outbreaks in Germany have many parallels with outbreaks at Qinghai Lake in central China, which was followed by outbreaks at Chaney Lake in Siberia in Russia and Erhel Lake in Mongolia. At Qinghai Lake, initial positives were restricted to one species (189 bar headed geese). The first OIE report however, had 519 positives, involving 5 species. Eventually the number of dead birds grew to over 5000 and the spring outbreak in China was followed by summer outbreaks in Russian and Mongolia.
In Russia, over 2 dozen species tested positive for H5N1 including a healthy crested grebe in August, 2005. The H5N1 in hunter killed birds indicated that the Qinghai strain had become well established in long range migratory birds and would migrate into Europe, the Middle East, and Africa,
Isolation of H5N1 from domestic poultry and wild birds in Romania, Turkey, and Egypt in 2005 confirmed the migration, but no country in western Europe of Africa reported H5N1 in 2005 prior. Fatal human infections confirmed in Turkey in early 2006 was followed by reports of H5N1 throughout Europe, the Middle East, and Africa. The detection in western Europe was attributed to a freezing over of lakes and westward movement of resident wild birds in the dead of winter in early 2006. Similarly, no H5N1 was reported in western Europe between late spring of 2007 and the recent outbreaks in the summer of 2007, other than one swan at the Dresden zoo in August, 2006.
However, the outbreaks in central Germany in the summer of 2007, coupled with positives in poultry and wild birds in the Czech Republic and France strongly suggests that H5N1 is endemic in Europe, and the detection/reporting failures are linked to surveillance programs in need of serious upgrades.
As noted above, the number of H5N1 positive wild birds in central Germany alone has exceeded 300. In 2006, over 700 birds were confirmed H5N1 positive in Europe, and most positives (343) were in Germany. As the number of confirmed cases approaches the 2006 record, it becomes increasingly clear that H5N1 arrived in western Europe in the fall of 2005, infected resident birds, and has become increasingly entrenched.
The finding of high levels in an asymptomatic resident swan near Kelbra Lake further supports the establishment of H5N1 in Europe, the Middle East, and Africa. This is the first report of H5N1 in an asymptomatic wild bird in western Europe.
H5N1 can infect a wide spectrum of bird species. Introductions into a region are not eliminated by culling of domestic poultry, or departure of long range migratory birds.
An increased surveillance program will help determine the level and distribution of H5N1 west of China.
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