Endemic H5N1 In Europe
Recombinomics Commentary
July 21, 2007
The recent OIE reports on the H5N1 outbreaks in Germany provide additional evidence supporting endemic H5N1 in Europe. The two reports detail confirmation of H5N1 in four states in Germany. Although the reports do not have the map coordinates for each isolate, the description clearly indicates that the vast majority of the new confirmed cases are in or near Kelbra Lake (see satellite map). The number of confirmed birds on the Saxony – Anhalt side has grown to 196, and the number on the Thuringia side is up to 49, including 19 confirmed cases on July 18. Similarly, on July 16 three more birds were confirmed at nearby Auleben, raising the total number of confirmed cases in or around Kelbra Lake to 251.
These confirmed cases are in addition to H5N1 confirmed cases in Bavaria and Saxony, bringing the total number of German confirmed cases between late June and mid-July to 285, which is approaching the total number of confirmed cases in Germany in 2006, which was 343 See Friedrich-Loeffer Institute report).
These confirmed cases in Germany involve wild swans, geese, grebes, and coots in addition to a domestic goose and cover 4 states in central Germany. Recent confirmations have been reported in swans in France and both domestic and wild birds in the Czech Republic. Media reports also describe a large die-off of great cormorants adjacent to the Baltic Sea in Russia (Kalingrad side of Curonian Spit). It is likely that increase surveillance will detect additional outbreaks in dead or dying wild birds. To date, the surveillance programs in western Europe have not detected H5N1 in a healthy live wild birds, although the number of H5N1 positive wild birds in Europe in 2006 exceeded 700.
Although the detection of H5N1 in June and July was unexpected because migration of long range migratory birds is minimal, H5N1 infections of resident birds would not be a surprise. The OIE Mission Report on H5N1 in Russia in 2005 described more than two dozen wild bird species that were H5n1 positive. Therefore establishment of H5N1 in resident birds in Europe in the fall of 2005 would not be surprising. H5N1 was confirmed in Romania, Western Turkey, and Egypt in wild birds infected in 2005, so widespread infections would not be unexpected.
Although official confirmations of H5N1 in western Europe and Africa did not happen until 2006, the surveillance in those regions remains suspect. In addition to failing to detect H5N1 in the fall of 2005, these programs also failed to find H5N1 in wild birds between the spring of 2006 and the summer of 2007 in any bird (dead or healthy), other than one bird at the Dresden zoo in August, 2006.
The failures to detect H5N1 now extend to countries neighboring Germany, which almost certainly have H5N1 in resident wild birds, which are supported by the sequence data on theH5N1 in Germany and the Czech Republic.
In 2007 H5N1 outbreaks were reported in Hungary and England. These isolates had 99.96% identity, suggesting that the outbreak in England may be linked to the outbreak in Hungary. In contrast, the identity between isolates in Germany and the Czech Republic is only 99.2%, indicating the outbreaks were introduced independently. Similarly, the identity between the isolates from the Czech Republic and Kuwait are 99.5%, again signaling independent introductions. Comparisons between the sequences in Bavaria and Saxony also identify distinct differences.
Thus, the sequences, frequency, geography, and temporal relations of the recent outbreaks strong support endemic H5N1 in Europe and all regions reporting H5N1 clade 2.2 infections in 2006. The H5N1 in wild birds is not affected by culling of domestic poultry, and there is little data to support the exclusion of resident wild birds from H5N1 infections linked to long range migratory birds.
These new confirmations dictate an enhanced H5N1 surveillance in Europe, the Middle East, and Africa, and raises serious doubts about the negative H5N1 being reported in the countries failing to file OIE reports in 2007.
Media Sources
Recombinomics Presentations
Recombinomics Publications
Recombinomics' Paper at Nature Precedings