Explore the vast range of titles available.

Fifty-four strains of H5N1 highly pathogenic avian influenza (HPAI) virus were isolated from wild birds in the ecosystems of northern Eurasia and from poultry in the south of western Siberia (July 2005), at the mouth of Volga River (November 2005), at Uvs-Nur Lake on the boundary of the Great Lakes Depression in western Mongolia and the Tyva Republic of Russia (June 2006), in the vicinity of Moscow (February 2007), in the southeastern part of the Russian Plain (September 2007 and December 2007), and in the far east (April 2008) of the Russian Federation and were phenotypically characterized and deposited into the Russian state collection of viruses. Complete genome nucleotide sequences for 24 strains were obtained and deposited into GenBank. In all cases when strains were isolated from both wild birds and poultry in the same outbreak these strains were genetically closely related to each other. Until 2008 all HPAI H5N1 strains isolated in northern Eurasia clustered genetically with the viruses from Kukunor Lake (Qinghai Province, China), known as genotype 2.2 or the “Qinghai-Siberian” genotype. The viruses from the Qinghai-Siberian genotype have continued to evolve from those initially introduced into western Siberia in 2005 into two genetic groups: “Iran–North Caucasian” and “Tyva-Siberian.” In vitro replication potential (50% tissue-culture infectious dose in porcine embryo kidney) of Qinghai-Siberian strains decreased over time, which could reflect decreasing virulence. Comparison of genome sequences with biological characteristics of the respective strains permitted us to identify point mutations in PB2, PB1, PA, HA, NP, NA, M2, NS1, and NS2 that possibly influenced the level of replication potential. The HPAI H5N1 virus, which penetrated into the south of the Russian Far East in spring 2008, belonged to genotype 2.3.2.

Highly pathogenic (HP) avian influenza A viruses (AIVs) subtype H5N1 (subclade 2.2) were detected in wild birds during outbreaks in France during winter 2006 and summer 2007 in la Dombes wetlands (eastern France) and in Moselle wetlands (northeastern France), respectively. Blood samples from apparently healthy wild birds were collected in 2006 and 2007 from the end of the outbreak to several weeks after the influenza A outbreak inside and outside the contaminated areas, and in 2008 outside the contaminated areas. The samples were tested for the presence and/or quantitation of serum antibodies to influenza A subtypes H5 and N1 using hemagglutination inhibition tests (HITs), a commercial N1-specific enzyme-linked immunosorbent assay kit, and virus neutralization assay. In the HIT, low pathogenicity (LP) and HP H5 AIVs (belonging to H5N1, H5N2, and H5N3 subtypes) were used as antigens. One hundred mute swans were bled in the la Dombes outbreak area in 2006. During 2007, 46 mallards, 69 common pochards, and 59 mute swans were sampled in the Moselle outbreak area. For comparison, blood samples were also collected in 2007 from 60 mute swans from the Marne department where no HP H5N1 influenza A cases have been reported, and in 2008 from 111 sacred ibises in western France where no HP H5N1 influenza A infections in wild birds have been reported either. Mute swans (irrespective of their origin and time of sampling) and sacred ibises (from an area with no known outbreaks) had the highest prevalence of positive sera in the H5 HIT (49–69% and 64%, respectively). The prevalence of anti-H5 antibodies in mallards and common pochards was lower (28% and 27%, respectively). Positive H5- and N1-antibody responses were also significantly associated in swans (irrespective of their origin and time of sampling) and in sacred ibises. However, in swans from the area without outbreaks, the HIT titer against an H5N1 LPAIV was significantly higher than against an H5N1 2.2.1 HPAIV, whereas no difference could be shown for swans from the outbreak areas sampled in 2006 and 2007. These results suggest that ibises and swans from areas without declared outbreaks had acquired humoral immunity after AIV infections with subtypes H5 and N1 but independently from HP H5N1 infection. However, for swans living in outbreak areas, it cannot be excluded that this immunity might result from either a subclinical or a nonlethal infection by HP H5N1.

In order to determine the actual prevalence of avian influenza viruses (AIVs) in wild birds in Bosnia and Herzegovina, extensive surveillance was carried out between October 2005 and April 2006. A total of 394 samples representing 41 bird species were examined for the presence of influenza A virus using virus isolation in embryonated chicken eggs, PCR, and nucleotide sequencing. AIV subtype H5N1 was detected in two mute swans (Cygnus olor). The isolates were determined to be highly pathogenic avian influenza (HPAI) virus and the hemagglutinin sequence was closely similar to A/Cygnus olor/Astrakhan/Ast05-2-10/2005 (H5N1). This is the first report of HPAI subtype H5N1 in Bosnia and Herzegovina.

In April 2008 an avian influenza outbreak was diagnosed in Primorsky Krai, Russia, during the spring migration of wild birds, and A/Chicken/Primorsky/85/08 H5N1 isolate was recovered. The virus had more than 99% genetic identity with A/Whooper Swan/Hokkaido/1/08 H5N1 and A/Whooper Swan/Hokkaido/2/08 H5N1 viruses that were isolated in April 2008 in Japan. The amino acid sequence of the hemagglutinin cleavage site (PQRERRRKRGLF) and intravenous pathotyping index value (IVPI 2.80) were determined; on this basis the virus was characterized as highly pathogenic. The hemagglutinin gene of the virus was shown to belong to clade 2.3.2 while other genes (PB1, PB2, PA, NP, NA, M, NS) were characteristic of Fujian-like sublineage, recovered in the territory of Russia for the first time.

Highly pathogenic (HP) avian influenza A viruses (AIVs) subtype H5N1 (subclade 2.2) were detected in wild birds during outbreaks in France during winter 2006 and summer 2007 in la Dombes wetlands (eastern France) and in Moselle wetlands (northeastern France), respectively. Blood samples from apparently healthy wild birds were collected in 2006 and 2007 from the end of the outbreak to several weeks after the influenza A outbreak inside and outside the contaminated areas, and in 2008 outside the contaminated areas. The samples were tested for the presence and/or quantitation of serum antibodies to influenza A subtypes H5 and Nl using hemagglutination inhibition tests (HITs), a commercial N1-specific enzyme-linked immunosorbent assay kit, and virus neutralization assay. In the HIT, low pathogenicity (LP) and HP H5 AIVs (belonging to H5N1, H5N2, and H5N3 subtypes) were used as antigens. One hundred mute swans were bled in the la Dombes outbreak area in 2006. During 2007, 46 mallards, 69 common pochards, and 59 mute swans were sampled in the Moselle outbreak area. For comparison, blood samples were also collected in 2007 from 60 mute swans from the Marne department where no HP H5N1 influenza A cases have been reported, and in 2008 from 111 sacred ibises in western France where no HP H5N1 influenza A infections in wild birds have been reported either. Mute swans (irrespective of their origin and time of sampling) and sacred ibises (from an area with no known outbreaks) had the highest prevalence of positive sera in the H5 HIT (49-69% and 64%, respectively). The prevalence of anti-H5 antibodies in mallards and common pochards was lower (28% and 27%, respectively). Positive H5-and Í1-antibody responses were also significantly associated in swans (irrespective of their origin and time of sampling) and in sacred ibises. However, in swans from the area without outbreaks, the HIT titer against an H5N1 LPAIV was significantly higher than against an H5N1 2.2.1 HPAIV, whereas no difference could be shown for swans from the outbreak areas sampled in 2006 and 2007. These results suggest that ibises and swans from areas without declared outbreaks had acquired humoral immunity after AIV infections with subtypes H5 and N1 but independently from HP H5N1 infection. However, for swans living in outbreak areas, it cannot be excluded that this immunity might result from either a subclinical or a nonlethal infection by HP H5N1. Se detectaron virus de la influenza aviar de alta patogenicidad subtipo H5N1 (subclado 2.2) en aves silvestres durante los brotes en Francia en el invierno del año 2006 y en el verano del 2007 en los humedales de la región de La Dombes (al este de Francia) y en los humedales de la región de Moselle (al noreste de Francia), respectivamente. Muestras de sangre de aves silvestres aparentemente sanas, se recolectaron en los años 2006 y 2007 desde el final del brote a hasta varias semanas después en zonas dentro y fuera de las áreas contaminadas y en el año 2008 se recolectaron fuera de las zonas contaminadas. Las muestras fueron analizadas para determinar la presencia y cuantificación de anticuerpos séricos contra la influenza A subtipos H5 y Nl mediante pruebas de inhibición de la hemaglutinación, mediante un ensayo comercial de inmunoabsorción con enzimas ligadas específico para N1 y por la prueba de neutralización viral. Se utilizaron virus de baja y alta patogenicidad H5 (pertenecientes a los subtipos H5N1, H5N2 y H5N3) como antígenos en la prueba de inhibición de la hemaglutinación. Se sangraron cien cisnes durante la epidemia ocurrida en La Dombes en el 2006. Durante el 2007, se muestrearon 46 patos de collar, 69 porrones europeos y 59 cisnes en el área del brote del Moselle. Para efectos de comparación también se recolectaron muestras de sangre en el año 2007 a partir de 60 cisnes en el departamento de Marne donde no se habían reportado casos de influenza A subtipo H5N1 de alta patogenicidad y en el año 2008 se recolectaron muestras a partir de 111 ibis sagrados en el oeste de Francia, donde tampoco se han reportado infecciones en aves silvestres por influenza A subtipo H5N1 de alta patogenicidad. Los cisnes comunes (sin importar su origen y de la fecha de muestreo) y los ibis sagrados (de un área donde no había brotes reconocidos) tenían la mayor prevalência de sueros positivos por la prueba de inhibición de la hemaglutinación contra H5 (49-69% y 64%, respectivamente). La prevalência de anticuerpos contra H5 en patos de collar y en porrones europeos fue menor (28% y 27%, respectivamente). Las respuestas de anticuerpos positivas para H5 y Nl estuvieron también asociadas de forma significativa con cisnes (sin importar su origen y de la fecha de muestreo) y con ibis sagrados. Sin embargo, en los cisnes de la zona sin brotes, el título por inhibición de la hemaglutinación contra un virus de baja patogenicidad H5N1 fue significativamente mayor en comparación que la específica contra un virus de alta patogenicidad H5N1 2.2.1, mientras que no se pudo demostrar diferencia en los cisnes de las zonas con brotes muestreadas en los años 2006 y 2007. Estos resultados sugieren que los ibis y los cisnes de las zonas sin brotes declarados han adquirido inmunidad humoral después de la infección por el virus de la influenza aviar subtipos H5 y NI, pero de manera independiente de la infección por virus de alta patogenicidad H5N1. Sin embargo, para los cisnes que viven en las zonas de brote, no se puede excluir que esta inmunidad podría dar lugar a una infección subclínica o a una infección no letal por virus de alta patogenicidad H5N1.

We detected Eurasian-origin highly pathogenic avian influenza A(H5N1) virus belonging to the Gs/GD lineage, clade 2.3.4.4b, in wild waterfowl in 2 Atlantic coastal states in the United States. Bird banding data showed widespread movement of waterfowl within the Atlantic Flyway and between neighboring flyways and northern breeding grounds.

We present the results of Canada’s Interagency Surveillance Program for Avian Influenza in Wild Birds in the year following the first detection of highly pathogenic avian influenza virus (HPAIV) H5N1 on the continent. The surveillance program tested over 17,000 wild birds, both sick and apparently healthy, which revealed spatiotemporal and taxonomic patterns in HPAIV prevalence and mortality across Canada. The significant shift in the presence and distribution of HPAIV in Canada’s wild birds underscores the need for sustained investment in wild bird surveillance and collaboration across One Health partners.

The UK and Europe have seen successive outbreaks of highly pathogenic avian influenza across the 2020/21 and 2021/22 autumn/winter seasons. Understanding both the epidemiology and transmission of these viruses in different species is critical to aid mitigating measures where outbreaks cause extensive mortalities in both land- and waterfowl. Infection of different species can result in mild or asymptomatic outcomes, or acute infections that result in high morbidity and mortality levels. Definition of disease outcome in different species is of great importance to understanding the role different species play in the maintenance and transmission of these pathogens. Further, the infection of species that have conservation value is also important to recognise and characterise to understand the impact on what might be limited wild populations. Highly pathogenic avian influenza virus H5N1 clade 2.3.4.4b has been detected in great skuas (Stercorarius skua) across different colonies on islands off the shore of Scotland, Great Britain during summer 2021. A large number of great skuas were observed as developing severe clinical disease and dying during the epizootic and mortalities were estimated to be high where monitored. Of eight skuas submitted for post-mortem examination, seven were confirmed as being infected with this virus using a range of diagnostic assays. Here we overview the outbreak event that occurred in this species, listed as species of conservation concern in Great Britain and outline the importance of this finding with respect to virus transmission and maintenance.

We characterized highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b genotype D1.1 in wild birds and a human in British Columbia, Canada, during 2024. D1.1, the predominant genotype circulating in fall 2024, is a reassortment between Eurasian A3 lineage viruses, introduced to North America in 2022, and North American lineage viruses.

Highly pathogenic avian influenza viruses (HPAIVs) of hemagglutinin type H5 and clade 2.3.4.4b have widely spread within the northern hemisphere since 2020 and threaten wild bird populations, as well as poultry production. We present phylogeographic evidence that Iceland has been used as a stepping stone for HPAIV translocation from northern Europe to North America by infected but mobile wild birds. At least 2 independent incursions of HPAIV H5N1 clade 2.3.4.4b assigned to 2 hemagglutinin clusters, B1 and B2, are documented for summer‒autumn 2021 and spring 2022. Spread of HPAIV H5N1 to and among colony-breeding pelagic avian species in Iceland is ongoing. Potentially devastating effects (i.e., local losses >25%) on these species caused by extended HPAIV circulation in space and time are being observed at several affected breeding sites throughout the North Atlantic.