Genetic evidence for avian influenza H5N1 viral transmission along the Black Sea–Mediterranean Flyway

Abstract

The current epidemic of highly pathogenic avian influenza H5N1 virus is considered to pose a significant threat to the health of wild and domestic avian species, and even to human beings. The Black Sea-Mediterranean Flyway is one of the most important epidemic areas of H5N1. However, the epidemic along this flyway has not been fully explored. To better understand the role of hosts in the spread and evolution of H5N1 virus along the flyway, a phylogeographic study was conducted using haemagglutinin (HA) gene sequences obtained during [2005][2006][2007][2008][2009][2010][2011][2012][2013]. To infer phylodynamic spread in time and space, we used a flexible Bayesian statistical framework and modelled viral spatial diffusion as a continuous-time Markov-chain process along timemeasured genealogies. Our results revealed that H5N1 virus isolated from wild birds showed an increase in genetic variation of HA gene from [2005][2006][2007]. The mean genetic distance of viruses isolated from poultry reached its peak in 2010, and dropped in 2011, increasing again in 2012-2013. The reconstruction of virus circulation revealed a different viral-migration network of H5N1 virus by different hosts. Western Russia constituted a link in viral migration from Russia to Europe and Africa. Cross-species transmission of H5N1 viruses predominated in the migration network of the Black Sea-Mediterranean Flyway. This might be due to the migration of birds across long distances and interaction between local poultry and migratory birds. Additionally, the short-distance spread of H5N1 viruses among poultry followed local transportation networks. Such findings will aid in developing effective disease control and prevention strategies.

The genetics of highly pathogenic avian influenza viruses of subtype H5 in Germany, 2006–2020

“…The additional identification of highly similar sequences in Turkey and Nigeria indicates the further spread of clade 2.2.1 onto the African continent (Table S1; Fusaro et al, 2009;Oner et al, 2006;Salzberg et al, 2007;Zhou et al, 2016). In the federal state of Bavaria, two further genotypically distinct groups (termed Bavaria 1 and Bavaria 2) of isolates were identified, both clustering within clade 2.2.1 (Rinder et al, 2007).…”

“…During the epidemic in 2006, values of over 99% identity were established with sequences from Southern Europe, pinpointing the continuous circulation of clade 2.2.1 in the Southern European countries concurring with the geographic dynamics of the respective clade in Southern Germany (Brown, 2010; Fink et al., 2010; Nagy et al., 2009; Szeleczky et al., 2009; WHO, 2012). The additional identification of highly similar sequences in Turkey and Nigeria indicates the further spread of clade 2.2.1 onto the African continent (Table S1; Cattoli, Monne, et al., 2009; Fusaro et al., 2009; Oner et al., 2006; Salzberg et al., 2007; Zhou et al., 2016). In the federal state of Bavaria, two further genotypically distinct groups (termed Bavaria 1 and Bavaria 2) of isolates were identified, both clustering within clade 2.2.1 (Rinder et al., 2007).…”

“…The shorter circulation time frame of clade 2.2.2 in comparison with clade 2.2.1 could be the reason for the high similarity levels, and points towards a solitary introduction of the clade 2.2.2 into the area and subsequent spread from the Island of Ruegen into the surrounding regions (Harder et al., 2009; Starick et al., 2008). All segments of R65/06 ranged between sequence identity levels of 99% (polymerase basic 2 protein, PB2; polymerase basic 1 protein, PB1; polymerase acidic protein, PA; HA; nucleoprotein, NP; NA; non‐structural protein, NS) and 100% (matrix protein, MP) when aligned with a HPAIV H5N1 strain from the Astrakhan region of Central Russia, indicating a novel introduction into Germany, likewise from Asia (Brown, 2010; Coulombier et al., 2005; Lipatov et al., 2007; Shestopalov et al., 2006; Starick et al., 2008; Takekawa et al., 2010; Zhou et al., 2016).…”

Genetics of Japanese H5N8 high pathogenicity avian influenza viruses isolated in winter 2020–2021 and their genetic relationship with avian influenza viruses in Siberia

“…to play important roles in both the intracontinental dissemination of H5N1 viruses across the Eurasian continent (Zhou et al, 2016) and the intercontinental dissemination of H5N8 viruses from the Eurasian continent to the American continent (Lee et al, 2015).…”

Phylogeographic evidence for the inter- and intracontinental dissemination of avian influenza viruses via migration flyways

“…The strains spread to Europe and West Africa between October 2005 and February 2006 [21, 22]. The movement of migratory birds, as well as the poultry trade, played an important role in the spread of these viruses [21, 23, 24]. During the winter of 2014–2015, H5 HPAIVs related to the viruses circulating in Asia spread to North America [25, 26].…”