RESUMEN
Avian Alpha-influenza-virus (AIV) massively affects poultry, targeting mainly the respiratory tract for virus replication. Recently, two major H5N8 and H5N1 outbreaks caused tremendous losses in Algerian poultry. The clinical symptoms that had not been seen in the past didn't prompt a rapid reaction to control the epidemics. We report here the characteristics of these outbreaks and the epidemiological status of AIV in Algeria. Following autopsy observation samples from target organs were taken and analyzed by the classical real-time reverse transcription polymerase chain reaction (RRT-PCR). Specific PCR HA and NA identification was used for subtyping H5 and N1/N8 genes. Systemic damage was observed in the upper-respiratory tracts with hemorrhagic and congestive tracheas, lungs, proventriculus, gut, and cecal tonsils were bloody. Out of 77 positive cases 13 were H5N8, 8 H5N1, and 10 H5Nx strains. These findings raise questions about the strain's pathotype considering severe organ damage and high mortality.
Asunto(s)
Brotes de Enfermedades , Subtipo H5N1 del Virus de la Influenza A , Subtipo H5N8 del Virus de la Influenza A , Gripe Aviar , Animales , Argelia/epidemiología , Gripe Aviar/epidemiología , Gripe Aviar/virología , Subtipo H5N1 del Virus de la Influenza A/genética , Subtipo H5N1 del Virus de la Influenza A/patogenicidad , Brotes de Enfermedades/veterinaria , Subtipo H5N8 del Virus de la Influenza A/genética , Subtipo H5N8 del Virus de la Influenza A/patogenicidad , Subtipo H5N8 del Virus de la Influenza A/aislamiento & purificación , Ganado/virología , Aves de Corral/virología , Pollos/virología , Enfermedades de las Aves de Corral/virología , Enfermedades de las Aves de Corral/epidemiologíaRESUMEN
In the 2021/22 winter, one H5N1 and nine H5N8 high pathogenicity avian influenza viruses (HPAIVs) of clade 2.3.3.4b were isolated from the water in crane roosts on the Izumi plain, Japan. Additionally, we isolated low pathogenicity avian influenza viruses (LPAIVs) of five subtypes: H1N1, H4N2, H4N6, H7N7, and H10N4. H5N8 HPAIVs belonging to the G2a group were isolated throughout winter, whereas H5N1 HPAIV belonging to the G2b group were isolated only in early winter. These findings suggest co-circulation of both G2a and G2b HPAIVs in early winter. Although two H7N7 LPAIVs were isolated from cranes' roost water collected on the same day, the gene constellations of the two isolates were clearly different, indicating the contemporary invasion of at least two different genotypes of H7N7 LPAIVs in the Izumi plain. This study underscores the importance of monitoring both HPAIVs and LPAIVs to understand avian influenza virus ecology in migratory waterfowl populations.
Asunto(s)
Aves , Genotipo , Gripe Aviar , Filogenia , Estaciones del Año , Japón , Animales , Gripe Aviar/virología , Gripe Aviar/epidemiología , Aves/virología , Subtipo H5N1 del Virus de la Influenza A/genética , Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Subtipo H5N1 del Virus de la Influenza A/patogenicidad , Subtipo H5N1 del Virus de la Influenza A/clasificación , Microbiología del Agua , Virus de la Influenza A/genética , Virus de la Influenza A/aislamiento & purificación , Virus de la Influenza A/clasificación , Subtipo H5N8 del Virus de la Influenza A/genética , Subtipo H5N8 del Virus de la Influenza A/patogenicidad , Subtipo H5N8 del Virus de la Influenza A/aislamiento & purificación , Subtipo H5N8 del Virus de la Influenza A/clasificación , Subtipo H7N7 del Virus de la Influenza A/genética , Subtipo H7N7 del Virus de la Influenza A/patogenicidad , Subtipo H7N7 del Virus de la Influenza A/aislamiento & purificaciónRESUMEN
The recent concurrent emergence of H5N1, H5N6, and H5N8 avian influenza viruses (AIVs) has led to significant avian mortality globally. Since 2020, frequent human-animal interactions have been documented. To gain insight into the novel H5 subtype AIVs (i.e., H5N1, H5N6 and H5N8), we collected 6102 samples from various regions of China between January 2021 and September 2022, and identified 41 H5Nx strains. Comparative analyses on the evolution and biological properties of these isolates were conducted. Phylogenetic analysis revealed that the 41 H5Nx strains belonged to clade 2.3.4.4b, with 13 related to H5N1, 19 to H5N6, and 9 to H5N8. Analysis based on global 2.3.4.4b viruses showed that all the viruses described in this study were likely originated from H5N8, exhibiting a heterogeneous evolutionary history between H5N1 and H5N6 during 2015-2022 worldwide. H5N1 showed a higher rate of evolution in 2021-2022 and more sites under positive selection pressure in 2015-2022. The antigenic profiles of the novel H5N1 and H5N6 exhibited notable variations. Further hemagglutination inhibition assay suggested that some A(H5N1) viruses may be antigenically distinct from the circulating H5N6 and H5N8 strains. Mammalian challenge assays demonstrated that the H5N8 virus (21GD001_H5N8) displayed the highest pathogenicity in mice, followed by the H5N1 virus (B1557_H5N1) and then the H5N6 virus (220086_H5N6), suggesting a heterogeneous virulence profile of H5 AIVs in the mammalian hosts. Based on the above results, we speculate that A(H5N1) viruses have a higher risk of emergence in the future. Collectively, these findings unveil a new landscape of different evolutionary history and biological characteristics of novel H5 AIVs in clade 2.3.4.4b, contributing to a better understanding of designing more effective strategies for the prevention and control of novel H5 AIVs.
Asunto(s)
Evolución Molecular , Subtipo H5N1 del Virus de la Influenza A , Gripe Aviar , Filogenia , Animales , China/epidemiología , Gripe Aviar/virología , Gripe Aviar/epidemiología , Ratones , Subtipo H5N1 del Virus de la Influenza A/genética , Subtipo H5N1 del Virus de la Influenza A/patogenicidad , Subtipo H5N1 del Virus de la Influenza A/clasificación , Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Subtipo H5N8 del Virus de la Influenza A/genética , Subtipo H5N8 del Virus de la Influenza A/patogenicidad , Subtipo H5N8 del Virus de la Influenza A/clasificación , Subtipo H5N8 del Virus de la Influenza A/aislamiento & purificación , Virulencia , Virus de la Influenza A/genética , Virus de la Influenza A/patogenicidad , Virus de la Influenza A/clasificación , Pollos/virología , Ratones Endogámicos BALB C , Femenino , Aves/virología , HumanosRESUMEN
A free-range organic broiler (Gallus gallus domesticus) premises in Staffordshire was infected by high pathogenicity avian influenza virus (HPAIV) H5N8 during the 2020-2021 epizootic in the United Kingdom (UK). Following initial confirmation of the infection in poultry, multiple wild bird species were seen scavenging on chicken carcasses. Detected dead wild birds were subsequently demonstrated to have been infected and succumbed to HPAIV H5N8. Initially, scavenging species, magpie (Pica pica) and raven (Corvus corax) were found dead on the premises but over the following days, buzzards (Buteo buteo) were also found dead within the local area with positive detection of HPAIV in submitted carcasses. The subacute nature of microscopic lesions within a buzzard was consistent with the timeframe of infection. Finally, a considerable number of free-living pheasants (Phasianus colchicus) were also found dead in the surrounding area, with carcasses having higher viral antigen loads compared to infected chickens. Limited virus dissemination was observed in the carcasses of the magpie, raven, and buzzard. Further, an avirulent avian paramyxovirus type 1 (APMV-1) was detected within poultry samples as well as in the viscera of a magpie infected with HPAIV. Immunohistochemistry did not reveal colocalization of avian paramyxovirus antigens with lesions, supporting an avirulent APMV-1 infection. Overall, this case highlights scenarios in which bi-directional transmission of avian viral diseases between commercial and wild bird species may occur. It also underlines the importance of bio separation and reduced access when infection pressure from HPAIV is high.
Asunto(s)
Animales Salvajes , Pollos , Brotes de Enfermedades , Subtipo H5N8 del Virus de la Influenza A , Gripe Aviar , Enfermedades de las Aves de Corral , Animales , Gripe Aviar/transmisión , Gripe Aviar/virología , Gripe Aviar/epidemiología , Pollos/virología , Animales Salvajes/virología , Brotes de Enfermedades/veterinaria , Subtipo H5N8 del Virus de la Influenza A/aislamiento & purificación , Subtipo H5N8 del Virus de la Influenza A/patogenicidad , Subtipo H5N8 del Virus de la Influenza A/genética , Reino Unido/epidemiología , Enfermedades de las Aves de Corral/virología , Enfermedades de las Aves de Corral/transmisión , Enfermedades de las Aves de Corral/epidemiología , Aves de Corral/virología , Cuervos/virología , Aves/virologíaRESUMEN
Understanding the mammalian pathogenesis and interspecies transmission of HPAI H5N8 virus hinges on mapping its adaptive markers. We used deep sequencing to track these markers over five passages in murine lung tissue. Subsequently, we evaluated the growth, selection, and RNA load of eight recombinant viruses with mammalian adaptive markers. By leveraging an integrated non-linear regression model, we quantitatively determined the influence of these markers on growth, adaptation, and RNA expression in mammalian hosts. Furthermore, our findings revealed that the interplay of these markers can lead to synergistic, additive, or antagonistic effects when combined. The elucidation distance method then transformed these results into distinct values, facilitating the derivation of a risk score for each marker. In vivo tests affirmed the accuracy of scores. As more mutations were incorporated, the overall risk score of virus heightened, and the optimal interplay between markers became essential for risk augmentation. Our study provides a robust model to assess risk from adaptive markers of HPAI H5N8, guiding strategies against future influenza threats.
Asunto(s)
Subtipo H5N8 del Virus de la Influenza A , Gripe Aviar , Gripe Humana , Animales , Humanos , Ratones , Subtipo H5N8 del Virus de la Influenza A/genética , Pulmón , ARN , MamíferosRESUMEN
We isolated a high pathogenicity avian influenza (HPAI) virus from a common pochard (Aythya ferina) that was being attacked by a bird of prey in South Korea in December 2020. Genetic analyses indicated that the isolate was closely related to the clade 2.3.4.4b H5N8 HPAI viruses found in South Korea and Japan during the winter season of 2020-2021. The histopathological examination revealed multifocal necrotizing inflammation in the liver, kidney, and spleen. Viral antigens were detected in the liver, kidney, spleen, trachea, intestine, and pancreas, indicating the HPAI virus caused a systemic infection. The presence of immunoreactivity for the viral antigen was observed in the cells involved in multifocal necrotic inflammation. Notably, epitheliotropic-positive patterns were identified in the epithelial cells of the trachea, mucosal epithelium of the intestine, and ductular epithelium of the pancreas. These findings provide direct evidence supporting the possibility of HPAI transmission from infected waterfowl to predators.
Detectado en el acto: Aislamiento y caracterización de un virus de la influenza aviar de alta patogenicidad del clado 2.3.4.4b H5N8 de un porrón común (Aythya ferina) atacado por un halcón peregrino (Falco peregrinus). Se aisló un virus de la influenza aviar (HPAI) de alta patogenicidad de un porrón común (Aythya ferina) que estaba siendo atacado por un ave rapaz en Corea del Sur en diciembre de 2020. Los análisis genéticos indicaron que el aislado estaba estrechamente relacionado con virus de influenza aviar de alta patogenicidad H5N8, clado 2.3.4.4 b encontrados en Corea del Sur y Japón durante la temporada de invierno de 20202021. El examen histopatológico reveló inflamación necrotizante multifocal en hígado, riñón y bazo. Se detectaron antígenos virales en el hígado, el riñón, el bazo, la tráquea, el intestino y el páncreas, lo que indica que este virus de alta patogenicidad causó una infección sistémica. Se observó la presencia de inmunorreactividad para el antígeno viral en las células involucradas en la inflamación necrótica multifocal. En particular, se identificaron patrones epiteliotrópicos positivos en las células epiteliales de la tráquea, el epitelio mucoso del intestino y el epitelio ductular del páncreas. Estos hallazgos proporcionan evidencia directa que respalda la posibilidad de transmisión de HPAI de aves acuáticas infectadas a especies depredadoras.
Asunto(s)
Falconiformes , Subtipo H5N8 del Virus de la Influenza A , Gripe Aviar , Animales , Gripe Aviar/virología , Subtipo H5N8 del Virus de la Influenza A/patogenicidad , Subtipo H5N8 del Virus de la Influenza A/fisiología , Subtipo H5N8 del Virus de la Influenza A/genética , Falconiformes/virología , República de Corea , Filogenia , GalliformesRESUMEN
Since 2020, clade 2.3.4.4b highly pathogenic avian influenza H5N8 and H5N1 viruses have swept through continents, posing serious threats to the world. Through comprehensive analyses of epidemiological, genetic, and bird migration data, we found that the dominant genotype replacement of the H5N8 viruses in 2020 contributed to the H5N1 outbreak in the 2021/2022 wave. The 2020 outbreak of the H5N8 G1 genotype instead of the G0 genotype produced reassortment opportunities and led to the emergence of a new H5N1 virus with G1's HA and MP genes. Despite extensive reassortments in the 2021/2022 wave, the H5N1 virus retained the HA and MP genes, causing a significant outbreak in Europe and North America. Furtherly, through the wild bird migration flyways investigation, we found that the temporal-spatial coincidence between the outbreak of the H5N8 G1 virus and the bird autumn migration may have expanded the H5 viral spread, which may be one of the main drivers of the emergence of the 2020-2022 H5 panzootic.IMPORTANCESince 2020, highly pathogenic avian influenza (HPAI) H5 subtype variants of clade 2.3.4.4b have spread across continents, posing unprecedented threats globally. However, the factors promoting the genesis and spread of H5 HPAI viruses remain unclear. Here, we found that the spatiotemporal genotype replacement of H5N8 HPAI viruses contributed to the emergence of the H5N1 variant that caused the 2021/2022 panzootic, and the viral evolution in poultry of Egypt and surrounding area and autumn bird migration from the Russia-Kazakhstan region to Europe are important drivers of the emergence of the 2020-2022 H5 panzootic. These findings provide important targets for early warning and could help control the current and future HPAI epidemics.
Asunto(s)
Subtipo H5N1 del Virus de la Influenza A , Subtipo H5N8 del Virus de la Influenza A , Gripe Aviar , Animales , Aves , Genotipo , Virus de la Influenza A/fisiología , Subtipo H5N1 del Virus de la Influenza A/genética , Subtipo H5N1 del Virus de la Influenza A/fisiología , Subtipo H5N8 del Virus de la Influenza A/genética , Subtipo H5N8 del Virus de la Influenza A/fisiología , Gripe Aviar/epidemiología , Gripe Aviar/virología , Filogenia , Aves de CorralRESUMEN
During the winter of 2020-2021, numerous outbreaks of high pathogenicity avian influenza (HPAI) were caused by viruses of the subtype H5N8 in poultry over a wide region in Japan. The virus can be divided into five genotypes-E1, E2, E3, E5, and E7. The major genotype responsible for the outbreaks was E3, followed by E2. To investigate the cause of these outbreaks, we experimentally infected chickens with five representative strains of each genotype. We found that the 50% chicken infectious dose differed by up to 75 times among the five strains, and the titer of the E3 strains (102.75 50% egg infectious dose (EID50)) was the lowest, followed by that of the E2 strains (103.50 EID50). In viral transmission experiments, in addition to the E3 and E2 strains, the E5 strain was transmitted to naïve chickens with high efficiency (>80%), whereas the other strains had low efficiencies (<20%). We observed a clear difference in the virological characteristics among the five strains isolated in the same season. The higher infectivity of the E3 and E2 viruses in chickens may have caused the large number of HPAI outbreaks in Japan during this season.
Asunto(s)
Subtipo H5N8 del Virus de la Influenza A , Gripe Aviar , Enfermedades de las Aves de Corral , Animales , Pollos , Subtipo H5N8 del Virus de la Influenza A/genética , Virulencia , Japón/epidemiología , Estaciones del Año , Brotes de Enfermedades/veterinariaRESUMEN
Highly pathogenic avian influenza viruses (HPAIVs) of subtype H5 of the Gs/GD/96 lineage remain a major threat to poultry due to endemicity in wild birds. H5N1 HPAIVs from this lineage were detected in 2021 in the United States (U.S.) and since then have infected many wild and domestic birds. We evaluated the pathobiology of an early U.S. H5N1 HPAIV (clade 2.3.4.4b, 2021) and two H5N8 HPAIVs from previous outbreaks in the U.S. (clade 2.3.4.4c, 2014) and Europe (clade 2.3.4.4b, 2016) in chickens and turkeys. Differences in clinical signs, mean death times (MDTs), and virus transmissibility were found between chickens and turkeys. The mean bird infective dose (BID50) of the 2021 H5N1 virus was approximately 2.6 log10 50% embryo infective dose (EID50) in chickens and 2.2 log10 EID50 in turkeys, and the virus transmitted to contact-exposed turkeys but not chickens. The BID50 for the 2016 H5N8 virus was also slightly different in chickens and turkeys (4.2 and 4.7 log10 EID50, respectively); however, the BID50 for the 2014 H5N8 virus was higher for chickens than turkeys (3.9 and ~0.9 log10 EID50, respectively). With all viruses, turkeys took longer to die (MDTs of 2.6-8.2 days for turkeys and 1-4 days for chickens), which increased the virus shedding period and facilitated transmission to contacts.
Asunto(s)
Subtipo H5N1 del Virus de la Influenza A , Subtipo H5N8 del Virus de la Influenza A , Virus de la Influenza A , Gripe Aviar , Enfermedades de las Aves de Corral , Animales , Estados Unidos/epidemiología , Subtipo H5N8 del Virus de la Influenza A/genética , Pollos , Subtipo H5N1 del Virus de la Influenza A/genética , Pavos , Virulencia , Virus de la Influenza A/genética , Animales SalvajesRESUMEN
Highly pathogenic avian influenza (HPAI) H5N1 activity has intensified globally since 2021, increasingly causing mass mortality in wild birds and poultry and incidental infections in mammals1-3. However, the ecological and virological properties that underscore future mitigation strategies still remain unclear. Using epidemiological, spatial and genomic approaches, we demonstrate changes in the origins of resurgent HPAI H5 and reveal significant shifts in virus ecology and evolution. Outbreak data show key resurgent events in 2016-2017 and 2020-2021, contributing to the emergence and panzootic spread of H5N1 in 2021-2022. Genomic analysis reveals that the 2016-2017 epizootics originated in Asia, where HPAI H5 reservoirs are endemic. In 2020-2021, 2.3.4.4b H5N8 viruses emerged in African poultry, featuring mutations altering HA structure and receptor binding. In 2021-2022, a new H5N1 virus evolved through reassortment in wild birds in Europe, undergoing further reassortment with low-pathogenic avian influenza in wild and domestic birds during global dissemination. These results highlight a shift in the HPAI H5 epicentre beyond Asia and indicate that increasing persistence of HPAI H5 in wild birds is facilitating geographic and host range expansion, accelerating dispersion velocity and increasing reassortment potential. As earlier outbreaks of H5N1 and H5N8 were caused by more stable genomic constellations, these recent changes reflect adaptation across the domestic-bird-wild-bird interface. Elimination strategies in domestic birds therefore remain a high priority to limit future epizootics.
Asunto(s)
Aves , Brotes de Enfermedades , Subtipo H5N1 del Virus de la Influenza A , Gripe Aviar , Internacionalidad , Animales , África/epidemiología , Animales Salvajes/virología , Asia/epidemiología , Aves/virología , Brotes de Enfermedades/prevención & control , Brotes de Enfermedades/estadística & datos numéricos , Brotes de Enfermedades/veterinaria , Europa (Continente)/epidemiología , Evolución Molecular , Especificidad del Huésped , Subtipo H5N1 del Virus de la Influenza A/clasificación , Subtipo H5N1 del Virus de la Influenza A/genética , Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Subtipo H5N1 del Virus de la Influenza A/patogenicidad , Subtipo H5N8 del Virus de la Influenza A/genética , Subtipo H5N8 del Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/epidemiología , Gripe Aviar/mortalidad , Gripe Aviar/transmisión , Gripe Aviar/virología , Mamíferos/virología , Mutación , Filogenia , Aves de Corral/virologíaRESUMEN
In the winter of 2021-2022, multiple subtypes (H5N8 and H5N1) of high pathogenicity avian influenza viruses (HPAIVs) were confirmed to be circulating simultaneously in Japan. Here, we phylogenetically and antigenically analyzed HPAIVs that were isolated from infected wild birds, an epidemiological investigation of affected poultry farms, and our own active surveillance study. H5 subtype hemagglutinin (HA) genes of 32 representative HPAIV isolates were classified into clade 2.3.4.4b lineage and subsequently divided into three groups (G2a, G2b, and G2d). All H5N8 HPAIVs were isolated in early winter and had HA genes belonging to the G2a group. H5N1 HPAIVs belong to the G2b and G2d groups. Although G2b viruses were widespread throughout the season, G2d viruses endemically circulated in Northeast Japan after January 2022. Deep sequence analysis showed that the four HPAIVs isolated at the beginning of winter had both N8 and N1 subtypes of neuraminidase genes. Environmental water-derived G2a HPAIV, A/water/Tottori/NK1201-2/2021 (H5N8), has unique polymerase basic protein 1 and nucleoprotein genes, similar to those of low pathogenicity avian influenza viruses (LPAIVs). These results indicate that multiple H5 HPAIVs and LPAIVs disseminated to Japan via transboundary winter migration of wild birds, and HPAIVs with novel gene constellations could emerge in these populations. Cross-neutralization test revealed that G2a H5N8 HPAIVs were antigenically distinct from a G2b H5N1 HPAIV, suggesting that antibody pressure in wild birds was involved in the transition of the HPAIV groups during the season.
Asunto(s)
Subtipo H5N1 del Virus de la Influenza A , Subtipo H5N8 del Virus de la Influenza A , Virus de la Influenza A , Gripe Aviar , Animales , Aves de Corral , Subtipo H5N8 del Virus de la Influenza A/genética , Japón/epidemiología , Virulencia , Granjas , Estaciones del Año , Aves , Animales Salvajes , Gripe Aviar/epidemiología , Virus de la Influenza A/genética , Agua , FilogeniaRESUMEN
Clade 2.3.4.4 H5Nx highly pathogenic avian influenza viruses (HPAIVs) of the "goose/Guangdong" lineage have caused a series of European epizootics since 2014. During autumn/winter 2020-2021, several H5Nx subtypes were detected in the UK, with H5N8 being the dominant subtype in wild birds and poultry. Despite the greater subtype diversity (due to viral neuraminidase gene reassortment) reported in wild birds, only H5N8 and H5N1 subtypes caused clade 2.3.4.4 UK HPAIV poultry outbreaks during this period. The direct inoculation of layer chickens showed that H5N8-2020 was more infectious than H5N1-2020, which supported the European H5N8 dominance during that season. However, the mean death time was longer for H5N8-2020 (3.42 days) than for H5N1-2020 (2.17 days). Transmission from directly infected to naive in-contact chickens was inefficient for both subtypes. Histological lesions, the tissue dissemination of viral antigen, and nucleic acid were more extensive and abundant and accumulated more rapidly for H5N1-2020 compared with H5N8-2020. Although inefficient, H5N1-2020 transmission was faster, with its greater virulence indicating that this subtype posed a major concern, as subsequently shown during H5N1 dominance of the clade 2.3.4.4 epizootic since autumn 2021. An evaluation of these in vivo viral characteristics is key to understanding the continuing poultry threats posed by clade 2.3.4.4 H5Nx HPAIVs.
Asunto(s)
Subtipo H5N1 del Virus de la Influenza A , Subtipo H5N8 del Virus de la Influenza A , Virus de la Influenza A , Animales , Pollos , Subtipo H5N1 del Virus de la Influenza A/genética , Subtipo H5N8 del Virus de la Influenza A/genética , Virulencia , Virus de la Influenza A/genética , Reino Unido/epidemiologíaRESUMEN
During the 2020-2021 winter, Eurasian countries experienced large outbreaks caused by the clade 2.3.4.4b H5N8 subtype high pathogenicity avian influenza viruses (HPAIVs) in the wild bird populations. At least seven gene constellations have been found in the causal HPAIVs. When and where the various HPAIVs emerged remains unclear. Here, we successfully cloned H5N8 HPAIVs with multiple gene constellations from a tracheal swab of a dead mallard found at its wintering site in Japan in January 2021. According to their phylogeny, the bird was most likely co-infected with the E2 and E3 genotype clade 2.3.4.4b HPAIVs. The result indicates that feral waterbirds can be infected with multiple HPAIVs, and shed an HPAIV with novel gene constellation in Southern wintering sites.
Asunto(s)
Subtipo H5N8 del Virus de la Influenza A , Virus de la Influenza A , Gripe Aviar , Enfermedades de las Aves de Corral , Animales , Subtipo H5N8 del Virus de la Influenza A/genética , Virulencia , Patos , Gripe Aviar/epidemiología , Aves , Animales Salvajes , Virus de la Influenza A/genética , FilogeniaRESUMEN
Late in 2016, multiple reassortant highly pathogenic (HP) avian influenza virus (AIVs) H5N8 was detected. AIVs infect different isolated hosts with a specific viral tropism. In the current study, the whole genome of the Egyptian A/chicken/NZ/2022 was genetically characterized. The H5N8-A/Common-coot/Egypt/CA285/2016, A/duck/Egypt/SS19/2017 previously isolated in Egypt, and the recently circulating A/chicken/Egypt/NZ/2022 reassortant viruses' replication, pathogenicity, and viral load in comparison to the H5N1-Clade 2.2.1.2 were investigated on Madin-Darby canine kidney cell (MDCK), by using the cytopathic effect (CPE) percent and matrix-gene reverse transcription quantitative real-time polymerase chain reaction to compute the virus titer at various points in time. The A/chicken/Egypt/NZ/2022 virus was similar to the reassortant strain clade 2.3.4.4b discovered in farms in 2016. The 2 sub-groupings of hemagglutinin (HA) and neuraminidase (NA) genes were identified (I and II); the A/chicken/Egypt/NZ/2022 HA and NA genes were associated with subgroup II. The subgroup II of the HA gene was further divided into A and B owing to acquired specific mutations. The A/chicken/Egypt/NZ/2022 in our study was associated with subgroup B. The M, NS, PB1, and PB2 genes were shown to be clustered into clade 2.3.4.4b by full genome sequence analysis; however, the PA and NP genes were found to be associated with H6N2 viruses, which had particular mutations that improved viral virulence and mammalian transmission. The current results showed that the circulating H5N8 viruses were more variable than previous viruses analyzed in 2016 and 2017. Compared to other reassortant HPAI H5N8, and HPAI H5N1, the growth kinetics of A/chicken/Egypt/NZ/2022 had a high CPE without the addition of trypsin and the most viral copies with a significant difference (P < 0.01) in comparison to HPAI H5N8 and HPAI H5N1 reassortant viruses. Accordingly, the effective viral replication of A/chicken/Egypt/NZ/2022 in the MDCK than other viruses may play a factor in the spread and maintenance of specific reassortant H5N8 influenza virus in the field.
Asunto(s)
Enfermedades de los Perros , Subtipo H5N1 del Virus de la Influenza A , Subtipo H5N8 del Virus de la Influenza A , Virus de la Influenza A , Gripe Aviar , Animales , Perros , Subtipo H5N8 del Virus de la Influenza A/genética , Pollos , Subtipo H5N1 del Virus de la Influenza A/genética , Riñón/patología , Filogenia , MamíferosRESUMEN
Highly pathogenic avian influenza (HPAI) is a serious viral infection that causes massive economic losses in poultry. The current study investigated the HPAI virus prevalence in commercial broiler chicken flocks from 2019 to 2022. Organ samples, including trachea, cecal tonsils, spleen, brain, as well as tracheal and cloacal swabs, were harvested from 111 problematic broiler chicken flocks that suffered from variable mortalities accompanied with respiratory signs (103 H5-vaccinated and 8 nonvaccinated flocks) in Egypt during the observation duration. Molecular tools were used to analyze the samples, including real-time reverse transcription-polymerase chain reaction (rRT-PCR) and sequence analysis of some PCR positive strains. The results indicated that 24 flocks were positive for HPAI H5N8, representing 21.6%, with 22.3% (23/103) prevalence and 12.5% (1/8) detection in vaccinated and nonvaccinated flocks, respectively, and they were almost detected in the autumn and winter seasons. Phylogenetic evaluation of the hemagglutinin (HA) gene showed that the 6 Egyptian strains were clustered in clade 2.3.4.4b and allocated into 2 groups (I and II). The samples recovered in 2019 were clustered in new subgroup A, and samples recovered in 2020 to 2022 were clustered in new subgroup B with 10 nucleotide mutations (R72S, A83D, T140A). In conclusion, HPAI H5N8 is a serious threat even in vaccinated birds; to control such problems, periodic molecular monitoring with vaccine efficacy evaluation and the use of preventive strategies are recommended.
Asunto(s)
Subtipo H5N8 del Virus de la Influenza A , Gripe Aviar , Enfermedades de las Aves de Corral , Animales , Gripe Aviar/epidemiología , Pollos , Subtipo H5N8 del Virus de la Influenza A/genética , Granjas , Filogenia , Enfermedades de las Aves de Corral/epidemiologíaRESUMEN
H5N8 and H5N1 high pathogenicity avian influenza viruses (HPAIVs) caused outbreaks in poultry farms in Japan from November 2021 to May 2022. Hemagglutinin genes of these viruses belong to clade 2.3.4.4B and can be divided phylogenetically into the following groups: 20A, 20E, and 21E. In this study, we compared the infectivity and transmissibility of HPAIVs from three groups of chickens. Representative strains from 20A, 20E, and 21E groups are A/chicken/Akita/7C/2021(H5N8)(Akita7C), A/chicken/Kagoshima/21A6T/2021(H5N1)(Kagoshima6T), and A/chicken/Iwate/21A7T/2022(H5N1)(Iwate7T), respectively. Fifty percent lethal dose of Akita7C in chickens (103.83 fifty percent egg infectious dose (EID50)) was up to seven times lower than those of Kagoshima6T and Iwate7T (104.50 and 104.68 EID50, respectively). Mean death times for Akita7C- and Kagoshima6T-infected chickens (3.45 and 3.30 days, respectively) were at least a day longer than that of Iwate7T (2.20 days). Viral titers of the trachea and cloaca of Iwate7T-infected chicken were the highest detected. The transmission rate of the Akita7C strain (100%) was markedly higher than those of the two strains (<50%). These data suggest that the infectivity and transmissibility of the Akita7C strain (H5N8) in chickens are higher than those of H5N1 viruses, providing fundamental information needed for formulating effective prevention and control strategies for HPAI outbreaks.
Asunto(s)
Subtipo H5N1 del Virus de la Influenza A , Subtipo H5N8 del Virus de la Influenza A , Virus de la Influenza A , Gripe Aviar , Animales , Pollos , Subtipo H5N1 del Virus de la Influenza A/genética , Japón/epidemiología , Subtipo H5N8 del Virus de la Influenza A/genética , Estaciones del Año , Virulencia , Gripe Aviar/epidemiologíaRESUMEN
H5N8, a highly pathogenic avian influenza, has become a new zoonotic threat in recent years. As of December 28, 2021, at least 3,206 H5N8 cases had been reported in wild birds and poultry worldwide. In January 2021, a novel virus strain named A/goose/China/1/2021 was isolated during an H5N8 goose influenza outbreak in northeastern China. The PB2, PB1, HA, and M genes of A/goose/China/1/2021 were highly identical to those of H5N8 strains emerging in Kazakhstan and Russia in Central Asia from August to September 2020, while the remaining four genes had the closest homology to those of H5N8 viruses isolated in South Korea in East Asia from November to December 2020. We thus speculate that A/goose/China/1/2021 is likely a reassortant virus that formed in the 2020 to 2021 influenza season and that the migratory birds via the two migration routes of Central Asia and East Asia-Australia may have played an essential role in the genetic reassortment of this virus. The phylogenetic analysis indicated that the HA genes of H5N8 viruses belonging to group II of subclade 2.3.4.4b, including A/goose/China/1/2021, may be derived from strains in Central Asia. Given the complex global spread of H5N8 virus, our study highlights the necessity to strengthen the function of the global surveillance network for H5N8 virus and to accelerate the pace of vaccine development to confront the current challenges posed by H5N8 virus of subclade 2.3.4.4. IMPORTANCE H5N8, a highly pathogenic avian influenza, not only has an impact on public health, but also has a huge negative impact on animal health, food safety, safety, and even on the local and international economy. The migratory wild birds play a vital role in the intercontinental transmission of H5N8 virus. It is urgent that we should strengthen the function of the global surveillance network for H5N8 virus and accelerate the pace of vaccine development to confront the current challenges posed by H5N8 virus of subclade 2.3.4.4.
Asunto(s)
Subtipo H5N8 del Virus de la Influenza A , Virus de la Influenza A , Gripe Aviar , Animales , Animales Salvajes , China/epidemiología , Gansos , Subtipo H5N8 del Virus de la Influenza A/genética , Gripe Aviar/epidemiología , FilogeniaRESUMEN
Migratory birds play a critical role in the rapid spread of highly pathogenic avian influenza (HPAI) H5N8 virus clade 2.3.4.4 across Eurasia. Elucidating the timing and pattern of virus transmission is essential therefore for understanding the spatial dissemination of these viruses. In this study, we surveyed >27,000 wild birds in China, tracked the year-round migration patterns of 20 bird species across China since 2006, and generated new HPAI H5N8 virus genomic data. Using this new data set, we investigated the seasonal transmission dynamics of HPAI H5N8 viruses across Eurasia. We found that introductions of HPAI H5N8 viruses to different Eurasian regions were associated with the seasonal migration of wild birds. Moreover, we report a backflow of HPAI H5N8 virus lineages from Europe to Asia, suggesting that Europe acts as both a source and a sink in the global HPAI virus transmission network.
Asunto(s)
Subtipo H5N8 del Virus de la Influenza A , Virus de la Influenza A , Gripe Aviar , Animales , Subtipo H5N8 del Virus de la Influenza A/genética , Aves , Virus de la Influenza A/genética , Animales Salvajes , Gripe Aviar/epidemiología , Europa (Continente)/epidemiología , Asia/epidemiología , Filogenia , Brotes de EnfermedadesRESUMEN
INTRODUCTION: Avian influenza viruses are members of the Orthomyxoviridae family, considered highly pathogenic (HPAI). They result from genetic variations from their low virulence predecessors. HPAI is a global problem. Large outbreaks of HAPI have significant health and economic impacts. OBJECTIVE: The objective of this study was to assess the prevalence of the H5N8 Influenza virus in birds, as well as to assess its variability according to the countries and years. METHODS: A systematic review of the literature was carried out in six databases (Web of Sciences, Scopus, PubMed, SciELO, Lilacs and Google Scholar) to evaluate the proportion of birds infected with the H5N8 Influenza virus, by molecular and immunological techniques. A meta-analysis was performed using a random-effects model to calculate the pooled prevalence, 95% confidence intervals (95%CI). A 2-tailed 5% alpha level was used for hypothesis testing. Measures of heterogeneity were estimated and reported, including the Cochrane Q statistic, the I2 index, and the tau-squared test. In addition, bird species performed subgroup analyzes. RESULTS: 152 data groups were analyzed, a combined prevalence of 1.6% (95% CI 1.3-1.9%) was found for molecular studies, and the ELISA study yielded a seroprevalence of 66.7%; those results of molecular detection varied by year, from 0.2% in 2014 to 52.6% in 2020 and 96.9% in 2015. CONCLUSION: The combined prevalence was substantial because large outbreaks have caused severe economic repercussions. In addition, it is considered a serious concern for public health due to its possible zoonotic activity.
Asunto(s)
Subtipo H5N8 del Virus de la Influenza A , Gripe Aviar , Gripe Humana , Humanos , Animales , Subtipo H5N8 del Virus de la Influenza A/genética , Gripe Aviar/epidemiología , Estudios Seroepidemiológicos , Animales Salvajes , Aves , Brotes de Enfermedades , Gripe Humana/epidemiología , FilogeniaRESUMEN
Multiple incursions of different subtypes of highly pathogenic avian influenza (HPAI) A/H5NX viruses have caused widely considerable outbreaks in poultry and hundreds of human infections. Extensive reassortment events associated with currently circulating clade 2.3.4.4b of A/H5NX viruses have been widely recorded. Wild migratory birds contribute to the spillover of diverse viruses throughout their migration flyways. During our active surveillance of avian influenza in Egypt, we successfully isolated and fully characterized HPAI A/H5N5 virus of clade 2.3.4.4b that was detected in a healthy purple heron. The Egyptian H5N5 virus is genotypically similar with the same subtype that was detected in the far east of Russia and several European countries. The antigenic analysis showed that the Egyptian H5N5 virus is distinct from HPAI A(H5N8) viruses in Egypt. The virus preferentially binds to avian-like receptors rather than human-like receptors. Our results showed that the virus caused 100% and 60% lethality in chicken and mice respectively. Increasing active surveillance efforts, monitoring the dynamics of emerging AIVs, and risk assessment implementation should be globally applied especially in hot spot regions like Egypt.