Highly Pathogenic Avian Influenza H5N8 Clade 2.3.4.4b in Germany in 2016/2017

Abstract

Here, we report on the occurrence of highly pathogenic avian influenza (HPAI) H5Nx clade 2.3.4.4b in Germany. Between November 8, 2016, and September 30, 2017, more than 1,150 cases of HPAI H5Nx clade 2.3.4.4b in wild birds and 107 outbreaks in birds kept in captivity (92 poultry holdings and 15 zoos/animal parks) were reported in Germany. This HPAI epidemic is the most severe recorded in Germany so far. The viruses were apparently introduced by migratory birds, sparking an epidemic among wild birds across Germany with occasional incursions into poultry holdings, zoos and animal parks, which were usually rapidly detected and controlled by stamping out. HPAI viruses (mainly subtype H5N8, in a few cases also H5N5) were found in dead wild birds of at least 53 species. The affected wild birds were water birds (including gulls, storks, herons, and cormorants) and scavenging birds (birds of prey, owls, and crows). In a number of cases, substantial gaps in farm biosecurity may have eased virus entry into the holdings. In a second wave of the epidemic starting from February 2017, there was epidemiological and molecular evidence for virus transmission of the infections between commercial turkey holdings in an area of high poultry density, which caused approximately 25% of the total number of outbreaks in poultry. Biosecurity measures in poultry holdings should be adapted. This includes, inter alia, wearing of stable-specific protective clothing and footwear, cleaning, and disinfection of equipment that has been in contact with birds and prevention of contacts between poultry and wild water birds.

Novel HPAIV H5N8 Reassortant (Clade 2.3.4.4b) Detected in Germany

“…Currently, no distinct precursor for the Ger-01-20 reassortant has been identified. The role of migratory waterbirds in the distribution of AIVs, as a catalyst for reassortment events and as the natural reservoir for LPAIV, has been demonstrated by numerous studies [3,[18][19][20]. Harboring of segments with sequences related to those identified in an H3N8 LPAIV in wild waterbirds from Central Russia along with segments from the HPAIV H5N8 reassortant found in Eurasia and Africa also infers a connection between the novel reassortant and migratory birds from the African Eurasian flyway as well as molting/resting grounds along the Russian-Kazakhstan/Mongolian/Chinese border [19].…”

“…The severe European epizootic of highly pathogenic avian influenza viruses (HPAIV), peaking during the winter of 2016-2017, was dominated by viral swarm incursions and frequent reassortment events [1]. All belonged to group B of clade 2.3.4.4, six reassortants classifying into three subtypes were identified in Germany from November 2016 to August 2018 [2][3][4]. Phylogenetic analyses of the H5N8 subtypes pointed to individual incursion events, as similar H5N8 HPAIV reassortants were found prior to the German epizootic in migratory wild water bird molting and resting areas in the regions surrounding Tartastan, Kurgan, and Lake Chany, Russian Federation [2,5].…”

Compatibility between haemagglutinin and neuraminidase drives the recent emergence of novel clade 2.3.4.4 H5Nx avian influenza viruses in China

“…Therefore, the current data could not confirm the pathogenic difference between nature clade 2.3.4.4 and clade 2.3.4 virus in mice. The recent H5N8 HPAIV clades 2.3.4.4a and 2.3.4.4b had no zoonotic potential, but this is prone to change as new viruses within clades 2.3.4.4c and 2.3.4.4d that may lead to fatal infections in mammals have already evolved in Asia (Globig et al., ; Lee et al., ; Li et al., ). We further analysed clade 2.3.4.4b and clade 2.3.4.4c sequences (Supporting Information Table S1) and found that no key sites near the receptor‐binding pocket (107Y, 148S, 150A, 165W, 167I, 195H, 202E, 206L, 207Y, 228K, 233S, 234Q and 237‐240G‐Q‐R‐G) were changed.…”

White-Tailed Sea Eagle (Haliaeetus albicilla) Die-Off Due to Infection with Highly Pathogenic Avian Influenza Virus, Subtype H5N8, in Germany

“…From 9 to 21 November 2016, an obvious die-off with about 330 dead birds, among them approximately 150 greater scaups Aythya marila ), 75 European herring gulls ( Larus argentatus ) and 25 great black-backed gulls ( Larus marinus ) [ 5 ], had been recorded on the shores of the islands of Ruden and Greifswalder Oie north of the isle of Usedom in the German part of the Baltic Sea, Mecklenburg-Western Pomerania. A portion of these birds were subsequently sampled and tested positive for HPAIV H5N8 by real-time RT-qPCR at the Germany National Reference Laboratory for Avian Influenza [ 4 , 6 , 7 ]. These events marked the onset of an unprecedented HPAIV epizootic affecting both wild birds and poultry throughout Europe.…”