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10/04/2018
Study published in “Viruses”
Insel Riems/Berlin, 4. October 2018. The most common unnatural causes of death in white-tailed sea eagles are lead poisoning and collisions with trains. During the winter of 2016/2017, however, many white-tailed eagles died in Northern Germany in circumstances unrelated to either cause.
nstead, at least 17 white-tailed sea eagles were killed by avian influenza of the highly pathogenic virus subtype H5N8, as a team of scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) and the Friedrich-Loeffler-Institute (Federal Research Institute for Animal Health, FLI) demonstrated. Avian influenza may become a new threat for this highly protected wild species. The study was published in the scientific journal “Viruses”.
The avian flu has been a threat to wild birds and poultry for decades. Especially chicken, ducks and geese as well as several species of waterfowl have been shown to be infected with different types of the influenza virus. This lead to epidemic outbreaks, for example in Mexico in 1992, in central Europe in 2006, in the USA in 2015 and in Europe again in 2016/2017.
Amongst raptors, peregrine falcons and common buzzards had been previously found to be infected but until now there was no such evidence regarding the largest bird in Europe, the white-tailed sea eagle (Haliaeetus albicilla). The investigation of 17 white-tailed sea eagles collected in the federal states of Mecklenburg-Western Pomerania, Hamburg, Schleswig-Holstein and Lower Saxonia during the winter of 2016/17 (14 of them being already dead and another 3 showing symptoms such as being overexcited and finding it difficult to move in a coordinated fashion) now demonstrated that white-tailed sea eagles can be killed by the avian influenza virus.
The analysis of the entire genome of the virus isolated from the collected birds revealed that it was not the widespread influenza subtype H5N1 but the subtype H5N8 which was responsible. More precisely, the analysis revealed that it the virus belonged to the clade 2.3.4.4b, considered to be highly aggressive for birds. It causes a lethal inflammation of the brain (polioencephalitis). Lead poisoning could be ruled out as a possible cause of death for the birds, as the analysis of liver and kidney tissue demonstrated.
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