RESUMO
Between 2013 and 2017, the A/Anhui/1/13-lineage (H7N9) low-pathogenicity avian influenza virus (LPAIV) was epizootic in chickens in China, causing mild disease, with 616 fatal human cases. Despite poultry vaccination, H7N9 has not been eradicated. Previously, we demonstrated increased pathogenesis in turkeys infected with H7N9, correlating with the emergence of the L217Q (L226Q H3 numbering) polymorphism in the haemagglutinin (HA) protein. A Q217-containing virus also arose and is now dominant in China following vaccination. We compared infection and transmission of this Q217-containing 'turkey-adapted' (ty-ad) isolate alongside the H7N9 (L217) wild-type (wt) virus in different poultry species and investigated the zoonotic potential in the ferret model. Both wt and ty-ad viruses demonstrated similar shedding and transmission in turkeys and chickens. However, the ty-ad virus was significantly more pathogenic than the wt virus in turkeys but not in chickens, causing 100 and 33% mortality in turkeys respectively. Expanded tissue tropism was seen for the ty-ad virus in turkeys but not in chickens, yet the viral cell receptor distribution was broadly similar in the visceral organs of both species. The ty-ad virus required exogenous trypsin for in vitro replication yet had increased replication in primary avian cells. Replication was comparable in mammalian cells, and the ty-ad virus replicated successfully in ferrets. The L217Q polymorphism also affected antigenicity. Therefore, H7N9 infection in turkeys can generate novel variants with increased risk through altered pathogenicity and potential HA antigenic escape. These findings emphasize the requirement for enhanced surveillance and understanding of A/Anhui/1/13-lineage viruses and their risk to different species.
Assuntos
Galinhas , Furões , Subtipo H7N9 do Vírus da Influenza A , Influenza Aviária , Perus , Animais , Perus/virologia , Influenza Aviária/virologia , Influenza Aviária/transmissão , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Galinhas/virologia , Virulência , China/epidemiologia , Doenças das Aves Domésticas/virologia , Doenças das Aves Domésticas/transmissão , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Humanos , Eliminação de Partículas Virais , Replicação Viral , Zoonoses/virologia , Influenza Humana/virologia , Influenza Humana/transmissãoRESUMO
During the UK 2020-2021 epizootic of H5Nx clade 2.3.4.4b high-pathogenicity avian influenza viruses (HPAIVs), high mortality occurred during incursions in commercially farmed common pheasants (Phasianus colchicus). Two pheasant farms, affected separately by H5N8 and H5N1 subtypes, included adjacently housed red-legged partridges (Alectoris rufa), which appeared to be unaffected. Despite extensive ongoing epizootics, H5Nx HPAIV partridge outbreaks were not reported during 2020-2021 and 2021-2022 in the UK, so it is postulated that partridges are more resistant to HPAIV infection than other gamebirds. To assess this, pathogenesis and both intra- and inter-species transmission of UK pheasant-origin H5N8-2021 and H5N1-2021 HPAIVs were investigated. Onward transmission to chickens was also assessed to better understand the risk of spread from gamebirds to other commercial poultry sectors. A lower infectious dose was required to infect pheasants with H5N8-2021 compared to H5N1-2021. However, HPAIV systemic dissemination to multiple organs within pheasants was more rapid following infection with H5N1-2021 than H5N8-2021, with the former attaining generally higher viral RNA levels in tissues. Intraspecies transmission to contact pheasants was successful for both viruses and associated with viral environmental contamination, while interspecies transmission to a first chicken-contact group was also efficient. However, further onward transmission to additional chicken contacts was only achieved with H5N1-2021. Intra-partridge transmission was only successful when high-dose H5N1-2021 was administered, while partridges inoculated with H5N8-2021 failed to shed and transmit, although extensive tissue tropism was observed for both viruses. Mortalities among infected partridges featured a longer incubation period compared to that in pheasants, for both viruses. Therefore, the susceptibility of different gamebird species and pathogenicity outcomes to the ongoing H5Nx clade 2.3.4.4b HPAIVs varies, but pheasants represent a greater likelihood of H5Nx HPAIV introduction into galliforme poultry settings. Consequently, viral maintenance within gamebird populations and risks to poultry species warrant enhanced investigation.
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Galliformes , Virus da Influenza A Subtipo H5N1 , Vírus da Influenza A Subtipo H5N8 , Vírus da Influenza A , Animais , Virulência , GalinhasRESUMO
The reemergence of the highly pathogenic avian influenza virus (HPAIV) subtype H5N1 in the United Kingdom in 2021-2022 has caused unprecedented epizootic events in wild birds and poultry. During the summer of 2022, there was a shift in virus transmission dynamics resulting in increased HPAIV infection in seabirds, and consequently, a profound impact on seabird populations. To understand the pathological impact of HPAIV in seabirds, we evaluated the virus antigen distribution and associated pathological changes in the tissues of great skua (Stercorarius skua, n = 8), long-tailed skua (Stercorarius longicaudus, n = 1), European herring gull (Larus argentatus, n = 5), and black-headed gull (Chroicocephalus ridibundus, n = 4), which succumbed to natural infection of HPAIV during the summer of 2022. Cases were collected from Shetland, including Scatness (mainland), No Ness (mainland), Clumlie (mainland), Hermaness (island), Fair Isle (island), Noss (island), and the West Midlands, South East, and South West of England. Grossly, gizzard ulceration was observed in one great skua and pancreatic necrosis was observed in 4 herring gulls, with intralesional viral antigen detected subsequently. Microscopical analysis revealed neuro-, pneumo-, lymphoid-, and cardiomyotropism of HPAIV H5N1, with the most common virus-associated pathological changes being pancreatic and splenic necrosis. Examination of the reproductive tract of the great skua revealed HPAIV-associated oophoritis and salpingitis, and virus replication within the oviductal epithelium. The emergence of HPAIV in seabirds Stercorariidae and Laridae, particularly during summer 2022, has challenged the dogma of HPAIV dynamics, posing a significant threat to wild bird life with potential implications for the reproductive performance of seabirds of conservation importance.
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Charadriiformes , Virus da Influenza A Subtipo H5N1 , Influenza Aviária , Animais , Charadriiformes/virologia , Influenza Aviária/virologia , Influenza Aviária/patologia , Influenza Aviária/epidemiologia , Reino Unido/epidemiologia , Virus da Influenza A Subtipo H5N1/patogenicidade , FemininoRESUMO
Under International Health Regulations from 2005, a human infection caused by a novel influenza A virus variant is considered an event that has potential for high public health impact and is immediately notifiable to the World Health Organisation. We here describe the clinical, epidemiological and virological features of a confirmed human case of swine influenza A(H1N2)v in England detected through community respiratory virus surveillance. Swabbing and contact tracing helped refine public health risk assessment, following this unusual and unexpected finding.
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Vírus da Influenza A Subtipo H1N1 , Influenza Humana , Infecções por Orthomyxoviridae , Doenças dos Suínos , Animais , Humanos , Suínos , Vírus da Influenza A Subtipo H1N2 , Vírus da Influenza A Subtipo H1N1/genética , Doenças dos Suínos/diagnóstico , Doenças dos Suínos/epidemiologia , Influenza Humana/diagnóstico , Influenza Humana/epidemiologia , Inglaterra/epidemiologiaRESUMO
Infectious bronchitis virus (IBV) is a highly contagious avian Gammacoronavirus that affects mainly chickens (Gallus gallus) but can circulate in other avian species. IBV constitutes a significant threat to the poultry industry, causing reduced egg yield, growth and mortality levels that can vary in impact. The virus can be transmitted horizontally by inhalation or direct/indirect contact with infected birds or contaminated fomites, vehicles, farm personnel and litter (Figure 1). The error-prone viral polymerase and recombination mechanisms mean diverse viral population results, with multiple genotypes, serotypes, pathotypes and protectotypes. This significantly complicates control and mitigation strategies based on vigilance in biosecurity and the deployment of vaccination.
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Galinhas , Infecções por Coronavirus , Vírus da Bronquite Infecciosa , Doenças das Aves Domésticas , Vírus da Bronquite Infecciosa/genética , Vírus da Bronquite Infecciosa/classificação , Vírus da Bronquite Infecciosa/fisiologia , Animais , Galinhas/virologia , Doenças das Aves Domésticas/virologia , Infecções por Coronavirus/virologia , Infecções por Coronavirus/veterináriaRESUMO
High pathogenicity avian influenza viruses (HPAIVs) cause high morbidity and mortality in poultry species. HPAIV prevalence means high numbers of infected wild birds could lead to spill over events for farmed poultry. How these pathogens survive in the environment is important for disease maintenance and potential dissemination. We evaluated the temperature-associated survival kinetics for five clade 2.3.4.4 H5Nx HPAIVs (UK field strains between 2014 and 2021) incubated at up to three temperatures for up to ten weeks. The selected temperatures represented northern European winter (4 °C) and summer (20 °C); and a southern European summer temperature (30 °C). For each clade 2.3.4.4 HPAIV, the time in days to reduce the viral infectivity by 90% at temperature T was established (DT), showing that a lower incubation temperature prolonged virus survival (stability), where DT ranged from days to weeks. The fastest loss of viral infectivity was observed at 30 °C. Extrapolation of the graphical DT plots to the x-axis intercept provided the corresponding time to extinction for viral decay. Statistical tests of the difference between the DT values and extinction times of each clade 2.3.4.4 strain at each temperature indicated that the majority displayed different survival kinetics from the other strains at 4 °C and 20 °C.
Assuntos
Vírus da Influenza A , Influenza Aviária , Temperatura , Animais , Influenza Aviária/virologia , Influenza Aviária/mortalidade , Vírus da Influenza A/patogenicidade , Vírus da Influenza A/genética , Vírus da Influenza A/classificação , Vírus da Influenza A/fisiologia , Cinética , Aves Domésticas/virologia , Animais Selvagens/virologia , Aves/virologia , Doenças das Aves Domésticas/virologia , Doenças das Aves Domésticas/mortalidadeRESUMO
Emerging pathogens can threaten human and animal health, necessitating reliable surveillance schemes to enable preparedness. We evaluated the repeatability and reproducibility of a method developed previously during a single year at one study site. Hunter-harvested ducks and geese were sampled for avian influenza virus at three discrete locations in the UK. H5N1 highly pathogenic avian influenza (HPAIV) was detected in four species (mallard [Anas platyrhynchos], Eurasian teal [Anas crecca], Eurasian wigeon [Mareca penelope] and pink-footed goose [Anser brachyrhynchus]) across all three locations and two non-HPAIV H5N1, influenza A positive detections were made from a mallard and Eurasian wigeon at two locations. Virus was detected within 1-to-4 days of sampling at every location. Application of rapid diagnostic methods to samples collected from hunter-harvested waterfowl offers potential as an early warning system for the surveillance and monitoring of emerging and existing strains of avian influenza A viruses in key avian species.
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Patos , Gansos , Influenza Aviária , Animais , Influenza Aviária/virologia , Influenza Aviária/epidemiologia , Reino Unido/epidemiologia , Patos/virologia , Reprodutibilidade dos Testes , Gansos/virologia , Virus da Influenza A Subtipo H5N1/isolamento & purificaçãoRESUMO
Although commercial vaccines against Newcastle Disease have been available for decades, outbreaks still occur in the face of vaccination Further vaccination may accelerate viral evolution resulting in a further reduction in vaccine efficacy. A key question is whether genotype-matched vaccines can confer better protection against contemporary type 1 Avian Paramyxoviruses. To assess this, an in vivo vaccine-challenge study was undertaken to assess protection afforded by 'genotype-matched' and commercial vaccine formulations. Groups of chickens were vaccinated twice (prime-boost) with an inactivated preparation of either La Sota Clone 30, AV632-chicken-Cyprus-13 (genotype VII.2), or mock vaccine, and later challenged with virulent AV632-chicken-Cyprus-13. Post vaccinal serological responses differed, although both vaccination/challenge groups showed similar levels of clinical protection compared to the unvaccinated group, where 100 % mortality was observed. Shedding was significantly reduced in the vaccinated groups compared to the unvaccinated group. Virus dissemination in the tissues of vaccinated birds was comparable, but onset of infection was delayed. Two mutations were observed in the HN gene of the heterologous vaccine group; H199N and I192M, the latter thought to be associated with increased fusogenic potential. These data demonstrate that existing vaccine formulations confer similar levels of clinical protection to contemporary strains and that the antigenic heterogeneity of circulating strains does not impact upon shedding profiles in immunised birds. In conclusion, the ability of virulent APMV-1 to cause disease in vaccinated flocks is unlikely to be the result of antigenic mismatch alone, and other factors likely contribute to vaccination failure and breakthrough.
Assuntos
Doença de Newcastle , Doenças das Aves Domésticas , Vacinas Virais , Animais , Galinhas , Vírus da Doença de Newcastle/genética , Doença de Newcastle/prevenção & controle , Vacinação/veterinária , Genótipo , Projetos de Pesquisa , Eliminação de Partículas Virais , Anticorpos Antivirais , Doenças das Aves Domésticas/prevenção & controleRESUMO
The United Kingdom (UK) and Europe have seen successive outbreaks of H5N1 clade 2.3.4.4b high-pathogenicity avian influenza virus (HPAIV) since 2020 peaking in the autumn/winter periods. During the 2021/22 season, a mass die-off event of Svalbard Barnacle Geese (Branta leucopsis) was observed on the Solway Firth, a body of water on the west coast border between England and Scotland. This area is used annually by Barnacle Geese to over-winter, before returning to Svalbard to breed. Following initial identification of HPAIV in a Barnacle Goose on 8 November 2021, up to 32% of the total Barnacle Goose population may have succumbed to disease by the end of March 2022, along with other wild bird species in the area. Potential adaptation of the HPAIV to the Barnacle Goose population within this event was evaluated. Whole-genome sequencing of thirty-three HPAIV isolates from wild bird species demonstrated that there had been two distinct incursions of the virus, but the two viruses had remained genetically stable within the population, whilst viruses from infected wild birds were closely related to those from poultry cases occurring in the same region. Analysis of sera from the following year demonstrated that a high percentage (76%) of returning birds had developed antibodies to H5 AIV. This study demonstrates genetic stability of this strain of HPAIV in wild Anseriformes, and that, at the population scale, whilst there is a significant impact on survival, a high proportion of birds recover following infection.
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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.
Assuntos
Animais Selvagens , Galinhas , Surtos de Doenças , Vírus da Influenza A Subtipo H5N8 , Influenza Aviária , Doenças das Aves Domésticas , Animais , Influenza Aviária/transmissão , Influenza Aviária/virologia , Influenza Aviária/epidemiologia , Galinhas/virologia , Animais Selvagens/virologia , Surtos de Doenças/veterinária , Vírus da Influenza A Subtipo H5N8/isolamento & purificação , Vírus da Influenza A Subtipo H5N8/patogenicidade , Vírus da Influenza A Subtipo H5N8/genética , Reino Unido/epidemiologia , Doenças das Aves Domésticas/virologia , Doenças das Aves Domésticas/transmissão , Doenças das Aves Domésticas/epidemiologia , Aves Domésticas/virologia , Corvos/virologia , Aves/virologiaRESUMO
Europe has suffered unprecedented epizootics of high pathogenicity avian influenza (HPAI) clade 2.3.4.4b H5N1 since Autumn 2021. As well as impacting upon commercial and wild avian species, the virus has also infected mammalian species more than ever observed previously. Mammalian species involved in spill over events have primarily been scavenging terrestrial carnivores and farmed mammalian species although marine mammals have also been affected. Alongside reports of detections of mammalian species found dead through different surveillance schemes, several mass mortality events have been reported in farmed and wild animals. In November 2022, an unusual mortality event was reported in captive bush dogs (Speothos venaticus) with clade 2.3.4.4b H5N1 HPAIV of avian origin being the causative agent. The event involved an enclosure of 15 bush dogs, 10 of which succumbed during a nine-day period with some dogs exhibiting neurological disease. Ingestion of infected meat is proposed as the most likely infection route.
Assuntos
Animais Selvagens , Virus da Influenza A Subtipo H5N1 , Infecções por Orthomyxoviridae , Animais , Virus da Influenza A Subtipo H5N1/patogenicidade , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Reino Unido/epidemiologia , Animais Selvagens/virologia , Infecções por Orthomyxoviridae/veterinária , Infecções por Orthomyxoviridae/virologia , Infecções por Orthomyxoviridae/mortalidade , Infecções por Orthomyxoviridae/transmissão , Canidae , Influenza Aviária/virologia , Influenza Aviária/mortalidade , Influenza Aviária/transmissãoRESUMO
In January 2020, increased mortality was reported in a small broiler breeder flock in County Fermanagh, Northern Ireland. Gross pathological findings included coelomitis, oophoritis, salpingitis, visceral gout, splenomegaly, and renomegaly. Clinical presentation included inappetence, pronounced diarrhoea, and increased egg deformation. These signs, in combination with increased mortality, triggered a notifiable avian disease investigation. High pathogenicity avian influenza virus (HPAIV) was not suspected, as mortality levels and clinical signs were not consistent with HPAIV. Laboratory investigation demonstrated the causative agent to be a low-pathogenicity avian influenza virus (LPAIV), subtype H6N1, resulting in an outbreak that affected 15 premises in Northern Ireland. The H6N1 virus was also associated with infection on 13 premises in the Republic of Ireland and six in Great Britain. The close genetic relationship between the viruses in Ireland and Northern Ireland suggested a direct causal link whereas those in Great Britain were associated with exposure to a common ancestral virus. Overall, this rapidly spreading outbreak required the culling of over 2 million birds across the United Kingdom and the Republic of Ireland to stamp out the incursion. This report demonstrates the importance of investigating LPAIV outbreaks promptly, given their substantial economic impacts.
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Galinhas , Surtos de Doenças , Fazendas , Vírus da Influenza A , Influenza Aviária , Doenças das Aves Domésticas , Aves Domésticas , Animais , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Surtos de Doenças/veterinária , Reino Unido/epidemiologia , Doenças das Aves Domésticas/virologia , Doenças das Aves Domésticas/epidemiologia , Irlanda/epidemiologia , Galinhas/virologia , Vírus da Influenza A/patogenicidade , Vírus da Influenza A/genética , Vírus da Influenza A/classificação , Aves Domésticas/virologia , FilogeniaRESUMO
Since 2016, A(H5Nx) high pathogenic avian influenza (HPAI) virus of clade 2.3.4.4b has become one of the most serious global threats not only to wild and domestic birds, but also to public health. In recent years, important changes in the ecology, epidemiology, and evolution of this virus have been reported, with an unprecedented global diffusion and variety of affected birds and mammalian species. After the two consecutive and devastating epidemic waves in Europe in 2020-2021 and 2021-2022, with the second one recognized as one of the largest epidemics recorded so far, this clade has begun to circulate endemically in European wild bird populations. This study used the complete genomes of 1,956 European HPAI A(H5Nx) viruses to investigate the virus evolution during this varying epidemiological outline. We investigated the spatiotemporal patterns of A(H5Nx) virus diffusion to/from and within Europe during the 2020-2021 and 2021-2022 epidemic waves, providing evidence of ongoing changes in transmission dynamics and disease epidemiology. We demonstrated the high genetic diversity of the circulating viruses, which have undergone frequent reassortment events, providing for the first time a complete overview and a proposed nomenclature of the multiple genotypes circulating in Europe in 2020-2022. We described the emergence of a new genotype with gull adapted genes, which offered the virus the opportunity to occupy new ecological niches, driving the disease endemicity in the European wild bird population. The high propensity of the virus for reassortment, its jumps to a progressively wider number of host species, including mammals, and the rapid acquisition of adaptive mutations make the trend of virus evolution and spread difficult to predict in this unfailing evolving scenario.
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Introduction: The Eidolon helvum fruit bat is one of the most widely distributed fruit bats in Africa and known to be a reservoir for several pathogenic viruses that can cause disease in animals and humans. To assess the risk of zoonotic spillover, we conducted a serological survey of 304 serum samples from E. helvum bats that were captured for human consumption in Makurdi, Nigeria. Methods: Using pseudotyped viruses, we screened 304 serum samples for neutralizing antibodies against viruses from the Coronaviridae, Filoviridae, Orthomyxoviridae and Paramyxoviridae families. Results: We report the presence of neutralizing antibodies against henipavirus lineage GH-M74a virus (odds ratio 6.23; p < 0.001), Nipah virus (odds ratio 4.04; p = 0.00031), bat influenza H17N10 virus (odds ratio 7.25; p < 0.001) and no significant association with Ebola virus (odds ratio 0.56; p = 0.375) in this bat cohort. Conclusion: The data suggest a potential risk of zoonotic spillover including the possible circulation of highly pathogenic viruses in E. helvum populations. These findings highlight the importance of maintaining sero-surveillance of E. helvum, and the necessity for further, more comprehensive investigations to monitor changes in virus prevalence, distribution over time, and across different geographic locations.