RESUMO
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
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
The highly pathogenic Avian Influenza virus (HPAIV) H5N1 has caused a global outbreak affecting both wild and domestic animals, predominantly avian species. To date, cases of the HPAIV H5 Clade 2.3.4.4b in penguins have exclusively been reported in African Penguins. In Chile, the virus was confirmed in pelicans in December 2022 and subsequently spread across the country, affecting several species, including Humboldt penguins. This study aims to provide an overview of the incidents involving stranded and deceased Humboldt penguins and establish a connection between these events and HPAIV H5N1. Historical data about strandings between 2009 and 2023 was collected, and samples from suspected cases in 2023 were obtained to confirm the presence of HPAIV H5N1. Between January and August 2023, 2,788 cases of stranded and deceased penguins were recorded. Out of these, a total of 2,712 penguins deceased, evidencing a significative increase in mortality starting in early 2023 coinciding with the introduction and spreading of HPAIV H5N1 in the country. Thirty-seven events were categorized as mass mortality events, with the number of deceased penguins varying from 11 to 98. Most cases (97â¯%) were observed in the North of Chile. One hundred and eighty-one specimens were subjected to HPAIV diagnosis, four of which tested positive for HPAIV H5N1. Spatial analysis validates the correlation between mass mortality events and outbreaks of HPAIV in Chile. However, the limited rate of HPAIV H5N1 detection, which can be attributed to the type and quality of the samples, requiring further exploration.
Assuntos
Surtos de Doenças , Virus da Influenza A Subtipo H5N1 , Influenza Aviária , Spheniscidae , Animais , Spheniscidae/virologia , Chile/epidemiologia , Surtos de Doenças/veterinária , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Influenza Aviária/mortalidadeAssuntos
Doenças dos Bovinos , Surtos de Doenças , Influenza Aviária , Pesquisadores , Zoonoses Virais , Animais , Bovinos , Humanos , Aves/virologia , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Doenças dos Bovinos/virologia , Surtos de Doenças/estatística & dados numéricos , Surtos de Doenças/veterinária , Influenza Aviária/epidemiologia , Influenza Aviária/mortalidade , Influenza Aviária/transmissão , Estados Unidos/epidemiologia , Zoonoses Virais/epidemiologia , Zoonoses Virais/transmissãoRESUMO
We describe the evolution of the outbreak of Highly Pathogenic Avian Influenza (HPAI) A(H5N1) in sea lions (Otaria flavescens) of South America. At least 24,000 sea lions died in Peru, Chile, Argentina, Uruguay, and Brazil between January-October 2023. The most plausible route of infection is cohabiting with or foraging on infected birds. However, we urge a detailed evaluation of the sea lions actual source of infection given that the concomitant massive wild bird mortalities registered in the Pacific Ocean did not occur in the Atlantic Ocean.
Assuntos
Virus da Influenza A Subtipo H5N1 , Leões-Marinhos , Animais , América do Sul/epidemiologia , Surtos de Doenças , Influenza Aviária/mortalidade , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Oceano Atlântico , Oceano Pacífico , Infecções por Orthomyxoviridae/veterinária , Infecções por Orthomyxoviridae/mortalidade , Infecções por Orthomyxoviridae/virologia , Infecções por Orthomyxoviridae/epidemiologia , Aves/virologiaRESUMO
Despite apparently minimal seabird deaths, grave concern for the next breeding season.
Assuntos
Virus da Influenza A Subtipo H5N1 , Influenza Aviária , Animais , Regiões Antárticas/epidemiologia , Aves , Estações do Ano , Influenza Aviária/epidemiologia , Influenza Aviária/mortalidade , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Migração AnimalRESUMO
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.
Assuntos
Aves , Surtos de Doenças , Virus da Influenza A Subtipo H5N1 , Influenza Aviária , Internacionalidade , Animais , África/epidemiologia , Animais Selvagens/virologia , Ásia/epidemiologia , Aves/virologia , Surtos de Doenças/prevenção & controle , Surtos de Doenças/estatística & dados numéricos , Surtos de Doenças/veterinária , Europa (Continente)/epidemiologia , Evolução Molecular , Especificidade de Hospedeiro , Virus da Influenza A Subtipo H5N1/classificação , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Virus da Influenza A Subtipo H5N1/patogenicidade , Vírus da Influenza A Subtipo H5N8/genética , Vírus da Influenza A Subtipo H5N8/isolamento & purificação , Influenza Aviária/epidemiologia , Influenza Aviária/mortalidade , Influenza Aviária/transmissão , Influenza Aviária/virologia , Mamíferos/virologia , Mutação , Filogenia , Aves Domésticas/virologiaAssuntos
Aves , Evolução Molecular , Virus da Influenza A Subtipo H5N1 , Influenza Aviária , Animais , Aves/virologia , Surtos de Doenças/estatística & dados numéricos , Surtos de Doenças/veterinária , Influenza Aviária/epidemiologia , Influenza Aviária/mortalidade , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/patogenicidadeRESUMO
Wild birds are the reservoir for all avian influenza viruses (AIV). In poultry, the transition from low pathogenic (LP) AIV of H5 and H7 subtypes to highly pathogenic (HP) AIV is accompanied mainly by changing the hemagglutinin (HA) monobasic cleavage site (CS) to a polybasic motif (pCS). Galliformes, including turkeys and chickens, succumb with high morbidity and mortality to HPAIV infections, although turkeys appear more vulnerable than chickens. Surprisingly, the genetic determinants for virulence and pathogenesis of HPAIV in turkeys are largely unknown. Here, we determined the genetic markers for virulence and transmission of HPAIV H7N1 in turkeys, and we explored the host responses in this species compared to those of chickens. We found that recombinant LPAIV H7N1 carrying pCS was avirulent in chickens but exhibited high virulence in turkeys, indicating that virulence determinants vary in these two galliform species. A transcriptome analysis indicated that turkeys mount a different host response than do chickens, particularly from genes involved in RNA metabolism and the immune response. Furthermore, we found that the HA glycosylation at residue 123, acquired by LP viruses shortly after transmission from wild birds and preceding the transition from LP to HP, had a role in virus fitness and virulence in chickens, though it was not a prerequisite for high virulence in turkeys. Together, these findings indicate variable virulence determinants and host responses in two closely related galliformes, turkeys and chickens, after infection with HPAIV H7N1. These results could explain the higher vulnerability to HPAIV of turkeys compared to chickens. IMPORTANCE Infection with HPAIV in chickens and turkeys, two closely related galliform species, results in severe disease and death. Although the presence of a polybasic cleavage site (pCS) in the hemagglutinin of AIV is a major virulence determinant for the transition of LPAIV to HPAIV, there are knowledge gaps on the genetic determinants (including pCS) and the host responses in turkeys compared to chickens. Here, we found that the pCS alone was sufficient for the transformation of a LP H7N1 into a HPAIV in turkeys but not in chickens. We also noticed that turkeys exhibited a different host response to an HPAIV infection, namely, a widespread downregulation of host gene expression associated with protein synthesis and the immune response. These results are important for a better understanding of the evolution of HPAIV from LPAIV and of the different outcomes and the pathomechanisms of HPAIV infections in chickens and turkeys.
Assuntos
Galinhas , Vírus da Influenza A Subtipo H7N1 , Influenza Aviária , Perus , Fatores de Virulência , Virulência , Animais , Galinhas/virologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A Subtipo H7N1/genética , Vírus da Influenza A Subtipo H7N1/patogenicidade , Influenza Aviária/mortalidade , Influenza Aviária/virologia , Perus/virologia , Virulência/genética , Fatores de Virulência/química , Fatores de Virulência/genéticaRESUMO
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.
Assuntos
Charadriiformes/virologia , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/virologia , Animais , Animais Selvagens/virologia , Surtos de Doenças , Virus da Influenza A Subtipo H5N1/classificação , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/patogenicidade , Influenza Aviária/epidemiologia , Influenza Aviária/mortalidade , Influenza Aviária/transmissão , Escócia/epidemiologia , Estações do Ano , VirulênciaRESUMO
Control measures in the case of high pathogenicity avian influenza (HPAI) outbreaks in poultry include culling, surveillance, and biosecurity; wild birds in captivity may also be culled, although some rare bird species should be rescued for conservation. In this study, two anti-influenza drugs, baloxavir marboxil (BXM) and peramivir (PR), used in humans, were examined in treating HPAI in birds, using chickens as a model. Chickens were infected with H5N6 HPAI virus and were treated immediately or 24 h from challenge with 20 mg/kg BXM or PR twice a day for five days. As per our findings, BXM significantly reduced virus replication in organs and provided full protection to chickens compared with that induced by PR. In the 24-h-delayed treatment, neither drug completely inhibited virus replication nor ensured the survival of infected chickens. A single administration of 2.5 mg/kg of BXM was determined as the minimum dose required to fully protect chickens from HPAI virus; the concentration of baloxavir acid, the active form of BXM, in chicken blood at this dose was sufficient for a 48 h antiviral effect post-administration. Thus, these data can be a starting point for the use of BXM and PR in treating captive wild birds infected with HPAI virus.
Assuntos
Ácidos Carbocíclicos/farmacologia , Antivirais/farmacologia , Galinhas/virologia , Dibenzotiepinas/farmacologia , Guanidinas/farmacologia , Vírus da Influenza A/efeitos dos fármacos , Influenza Aviária/tratamento farmacológico , Influenza Aviária/virologia , Morfolinas/farmacologia , Piridonas/farmacologia , Triazinas/farmacologia , Ácidos Carbocíclicos/uso terapêutico , Animais , Antivirais/uso terapêutico , Dibenzotiepinas/uso terapêutico , Monitoramento de Medicamentos , Guanidinas/uso terapêutico , Influenza Aviária/mortalidade , Morfolinas/uso terapêutico , Especificidade de Órgãos , Piridonas/uso terapêutico , Tempo para o Tratamento , Resultado do Tratamento , Triazinas/uso terapêutico , Eliminação de Partículas ViraisRESUMO
Salmonella and avian influenza virus are important pathogens affecting the poultry industry and human health worldwide. In this experimental study, we evaluated the consequences of co-infection of Salmonella enteritidis (SE) with H9N2 avian influenza virus (H9N2-AIV) in chickens. Four groups were included: control group, H9N2-AIV group, H9N2-AIV + SE group, and SE group. Infected chickens were intranasally inoculated with H9N2-AIV at 21 days of age and then orally administered SE on the same day. The birds were monitored for clinical signs, mortality rates, and alterations in body weight. Sera, intestinal fluids, oropharyngeal, and cloacal swabs, and tissue samples were collected at 2, 6, 10, and 14 days post-infection (dpi). Significant increases in clinical signs and mortality rates were observed in the H9N2-AIV + SE group. Moreover, chickens with co-infection showed a significant change in body weight. SE faecal shedding and organ colonization were significantly higher in the H9N2-AIV + SE group than in the SE group. H9N2-AIV infection compromised the systemic and mucosal immunity against SE, as evidenced by a significant decrease in lymphoid organ indices as well as systemic antibody and intestinal immunoglobulin A (IgA) responses to SE and a significant increase in splenic and bursal lesion scores. Moreover, SE infection significantly increased shedding titres and duration of H9N2-AIV. In conclusion, this is the first report of co-infection of SE with H9N2-AIV in chickens, which leads to increased pathogenicity, SE faecal shedding and organ colonization, and H9N2-AIV shedding titre and duration, resulting in substantial economic losses and environmental contamination, ultimately leading to increased zoonoses.
Assuntos
Galinhas/microbiologia , Vírus da Influenza A Subtipo H9N2/fisiologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Salmonelose Animal/microbiologia , Salmonella enteritidis/fisiologia , Animais , Coinfecção/veterinária , Fezes/microbiologia , Imunoglobulina A/imunologia , Influenza Aviária/mortalidade , Intestinos/microbiologia , Doenças das Aves Domésticas/mortalidade , Distribuição Aleatória , Salmonelose Animal/mortalidade , Eliminação de Partículas ViraisRESUMO
The estimation of farm-specific time windows for the introduction of highly-pathogenic avian influenza (HPAI) virus can be used to increase the efficiency of disease control measures such as contact tracing and may help to identify risk factors for virus introduction. The aims of this research are to (1) develop and test an accurate approach for estimating farm-specific virus introduction windows and (2) evaluate this approach by applying it to 11 outbreaks of HPAI (H5N8) on Dutch commercial poultry farms during the years 2014 and 2016. We used a stochastic simulation model with susceptible, infectious and recovered/removed disease stages to generate distributions for the period from virus introduction to detection. The model was parameterized using data from the literature, except for the within-flock transmission rate, which was estimated from disease-induced mortality data using two newly developed methods that describe HPAI outbreaks using either a deterministic model (A) or a stochastic approach (B). Model testing using simulated outbreaks showed that both method A and B performed well. Application to field data showed that method A could be successfully applied to 8 out of 11 HPAI H5N8 outbreaks and is the most generally applicable one, when data on disease-induced mortality is scarce.
Assuntos
Influenza Aviária/epidemiologia , Aves Domésticas/virologia , Animais , Surtos de Doenças , Fazendas , Influenza Aviária/mortalidade , Influenza Aviária/transmissão , Modelos Estatísticos , Fatores de TempoRESUMO
Ducks show notably higher resistance to highly pathogenic avian influenza viruses as compared to chickens. Here, we studied the age-dependent susceptibility in ducks to the infections caused by highly pathogenic avian influenza viruses. We intranasally infected ducks aged 1, 2, 4, and 8 weeks with highly pathogenic H5N6 avian influenza viruses isolated in South Korea in 2016. All the 1-and 2-week-old ducks died after infection, 20% of 3-week-old ducks died, and from the ducks aged 4 and 8 weeks, all of them survived. We performed microarray analysis and quantitative real-time PCR using total RNA isolated from the lungs of infected 2- and 4-week-old ducks to determine the mechanism underlying the age-dependent susceptibility to highly pathogenic avian influenza virus. Limited genes were found to be differentially expressed between the lungs of 2- and 4-week-old ducks. Cell damage-related genes, such as CIDEA and ND2, and the immune response-related gene NR4A3 were notably induced in the lungs of infected 2-week-old ducks compared to those in the lungs of infected 4-week-old ducks.
Assuntos
Patos/virologia , Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Fatores Etários , Animais , Expressão Gênica , Regulação Viral da Expressão Gênica , Influenza Aviária/mortalidade , Pulmão/metabolismo , Pulmão/virologia , Análise de Sequência com Séries de Oligonucleotídeos , Doenças das Aves Domésticas/mortalidade , Reação em Cadeia da Polimerase em Tempo Real , Carga ViralRESUMO
In Indonesia, the highly pathogenic avian influenza A/H5N1 virus has become endemic and has been linked with direct transmission to humans. From 2013 to 2014, we isolated avian influenza A/H5N1 and A/H3N6 viruses from poultry in Indonesia. This study aimed to reveal their pathogenicity in mammals using a mouse model. Three of the isolates, Av154 of A/H5N1 clade 2.3.2.1c, Av240 of A/H5N1 clade 2.1.3.2b, and Av39 of A/H3N6, were inoculated into BALB/c mice. To assess morbidity and mortality, we measured body weight daily and monitored survival for 20 d. Av154- and Av240-infected mice lost 25% of their starting body weight by day 7, while Av39-infected mice did not. Most of the Av154-infected mice died on day 8, while the majority of the Av240-infected mice survived until day 20. A 50% mouse lethal dose was calculated to be 2.0 × 101 50% egg infectious doses for Av154, 1.1 × 105 for Av240 and > 3.2 × 106 for Av39. The Av154 virus was highly virulent and lethal in mice without prior adaptation, suggesting its high pathogenic potential in mammals. The Av240 virus was highly virulent but modestly lethal, whereas the Av39 virus was neither virulent nor lethal. Several mammalian adaptive markers of amino acid residues were associated with the highly virulent and lethal phenotypes of the Av154 virus.
Assuntos
Virus da Influenza A Subtipo H5N1/patogenicidade , Influenza Aviária/virologia , Influenza Humana/virologia , Aves Domésticas/virologia , Sequência de Aminoácidos , Animais , Peso Corporal , Feminino , Humanos , Indonésia , Vírus da Influenza A/classificação , Vírus da Influenza A/patogenicidade , Influenza Aviária/mortalidade , Influenza Humana/mortalidade , Camundongos , Camundongos Endogâmicos BALB C , Modelos Animais , Infecções por Orthomyxoviridae/mortalidade , Infecções por Orthomyxoviridae/virologia , Fenótipo , VirulênciaRESUMO
Highly pathogenic (HP) H5N1, clade 2.2.1, and low pathogenic avian influenza (LPAI) H9N2 viruses, G1-B lineage, are endemic in poultry in Egypt and have co-circulated for almost a decade. Surprisingly, no inter-subtypic reassortment events have been reported from the field during that time. After the introduction of HPAIV H5N8, clade 2.3.4.4b, in Egyptian poultry in 2016, suddenly HP H5N2 reassortants with H9N2 viruses emerged. The current analyses focussed on studying 32 duck flocks, 4 broiler chicken flocks, and 1 turkey flock, suffering from respiratory manifestations with moderate to high mortality reared in two Egyptian governorates during 2019. Real-time RT-PCR substantiated the presence of HP H5N8 in 21 of the 37 investigated flocks with mixed infection of H9N2 in two of them. HP H5N1 was not detected. Full hemagglutinin (HA) sequencing of 10 samples with full-genome sequencing of three of them revealed presence of a single genotype. Very few substituting mutations in the HA protein were detected versus previous Egyptian HA sequences of that clade. Interestingly, amino acid substitutions in the Matrix (M2) and the Neuraminidase (NA) proteins associated with conferring both Amantadine and Oseltamivir resistance were present. Systematic reassortment analysis of all publicly available Egyptian whole genome sequences of HP H5N8 (n = 23), reassortant HP H5N2 (n = 2) and LP H9N2 (n = 53) viruses revealed presence of at least seven different genotypes of HPAI H5Nx viruses of clade 2.3.4.4b in Egypt since 2016. For H9N2 viruses, at least three genotypes were distinguishable. Heat mapping and tanglegram analyses suggested that several internal gene segments in both HP H5Nx and H9N2 viruses originated from avian influenza viruses circulating in wild bird species in Egypt. Based on the limited set of whole genome sequences available, annual replacement patterns of HP H5Nx genotypes emerged and suggested selective advantages of certain genotypes since 2016.
Assuntos
Vírus da Influenza A Subtipo H5N2/genética , Vírus da Influenza A Subtipo H5N8/genética , Influenza Aviária/virologia , Filogenia , Animais , Egito/epidemiologia , Genoma Viral , Genótipo , Vírus da Influenza A Subtipo H5N2/patogenicidade , Vírus da Influenza A Subtipo H5N8/patogenicidade , Influenza Aviária/epidemiologia , Influenza Aviária/mortalidade , Mortalidade , Aves Domésticas/virologia , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/mortalidade , Doenças das Aves Domésticas/virologiaRESUMO
H5N8 highly-pathogenic avian influenza viruses (HPAIVs, clade 2.3.4.4) have spread globally via migratory waterfowl. Pekin ducks infected with a UK virus (H5N8-2014) served as the donors of infection in three separate cohousing experiments to attempt onward transmission chains to sequentially introduced groups of contact ducks, chickens and turkeys. Efficient transmission occurred among ducks and turkeys up to the third contact stage, with all (100%) birds becoming infected. Introduction of an additional fourth contact group of ducks to the turkey transmission chain demonstrated retention of H5N8-2014's waterfowl-competent adaptation. However, onward transmission ceased in chickens at the second contact stage where only 13% became infected. Analysis of viral progeny at this contact stage revealed no emergent polymorphisms in the intra-species (duck) transmission chain, but both terrestrial species included changes in the polymerase and accessory genes. Typical HPAIV pathogenesis and mortality occurred in infected chickens and turkeys, contrasting with 5% mortality among ducks.
Assuntos
Galinhas/virologia , Patos/virologia , Vírus da Influenza A Subtipo H5N8/fisiologia , Influenza Aviária/transmissão , Perus/virologia , Tropismo Viral/fisiologia , Animais , Antígenos Virais/análise , Galinhas/genética , Patos/genética , Vírus da Influenza A Subtipo H5N8/imunologia , Vírus da Influenza A Subtipo H5N8/patogenicidade , Influenza Aviária/mortalidade , Polimorfismo Genético , Perus/genéticaRESUMO
This retrospective study highlights the degree of losses and time-course through which the 2015 highly pathogenic avian influenza (HPAI) outbreaks in Ghana were managed. A total of 102 760 birds from 35 farms across five regions in Ghana included in this study were affected. Out of this, 89.3% was from the Greater Accra region. Majority of the birds were culled (94.2%). Adult layers were most affected and destroyed (64.0%), followed by broilers (13.7%). Event initiation to reporting averaged 7.7 ± 1.3 days (range: 1-30 days). Laboratory confirmation to depopulation of birds averaged 2.2 ± 0.5 (0-15) days while depopulation to disinfection took 2.2 ± 0.7 (0-20) days. Overall, some farms took as long as 30 days to report the outbreak to the authorities, 15 days from confirmation to depopulation and 20 days from depopulation to disinfection. On average, outbreak management lasted 12.3 (2-43) days from event initiation to depopulation. The study reveals a significant number of avian losses and delays in HPAI reporting and management by the authorities in Ghana during the 2015 outbreak. This poses a high risk of spread to other farms and a threat to public health. Awareness creation for poultry farmers is necessary for early reporting, while further study is required to set thresholds for the management of such outbreaks by veterinary departments.
Assuntos
Surtos de Doenças , Controle de Infecções/métodos , Influenza Aviária/epidemiologia , Influenza Aviária/mortalidade , Animais , Aves , Gana/epidemiologia , Controle de Infecções/organização & administração , Estudos RetrospectivosRESUMO
In 2016/2017, a severe epidemic of HPAIV H5N8 clade 2.3.4.4 group B (H5N8B) affected Europe. To analyse the role of mallards in the spatiotemporal dynamics of global HPAIV H5N8B dispersal, mallards (Anas platyrhynchos), naturally exposed to various AIV and therefore seropositive, were challenged with H5N8B. All experiments were controlled by infection and co-housing of seronegative juvenile Pekin ducklings. All ducks that survived the first infection were re-challenged 21 dpi with the homologous H5N8B strain. After the first H5N8B infection, seropositive mallards showed only mild clinical symptoms. Moderate to low viral shedding, occurring particularly from the oropharynx and lasting for 7 days maximum, led to severe clinical disease of all contact ducklings. All challenged seronegative Pekin ducks and contact ducklings died or had to be euthanized. H5-specific antibodies were detected in surviving birds within 2 weeks. Virus and viral RNA could be isolated from several water samples until 6 and 9 dpi, respectively. Conversely, upon re-infection with homologous H5N8B neither inoculated nor contact ducklings showed any clinical symptoms, nor was an antibody titer increase of seropositive mallards or any seroconversion of contact ducklings observed. Mallard ducks naturally pre-exposed to LPAIV can play a role as a clinically unsuspicious virus reservoir for H5N8B effective in virus transmission. Mallards with homologous immunity did not contribute to virus transmission.
Assuntos
Vírus da Influenza A Subtipo H5N8/fisiologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Animais , Anticorpos Antivirais/sangue , Patos/virologia , Vírus da Influenza A Subtipo H5N8/genética , Vírus da Influenza A Subtipo H5N8/patogenicidade , Influenza Aviária/sangue , Influenza Aviária/mortalidade , Fígado/virologia , Doenças das Aves Domésticas/sangue , Doenças das Aves Domésticas/mortalidade , Virulência , Eliminação de Partículas ViraisRESUMO
La carga de enfermedad por influenza está bien documentada en países de clima templado, pero hasta la fecha en Honduras solo se ha realizado un estudio, siendo este el segundo con respecto a la carga médica asociada a influenza. Objetivo: Estimar el número de hospitalizaciones y defunciones, debidos a la influenza, como causante de las infecciones respiratorias agudas en la población. Material yMétodos: Se realizó un estudio descriptivo retrospectivo. Seutilizó tres fuentes de datos secundarias:registros de todos los egresos hospitalarios, resultados de detección viral por influenza y proyecciones de población por grupos de edad. Se estimó la tasa de incidencia y su intervalo de confianza al 95%, combinando las tres fuentes de datos. Resultados: Las hospitalizaciones en las infecciones respiratorias agudas graves (IRAG) J09-J18 asociadas a influenza en el 2011-2015 son mayores en los menores de cinco años, en donde las hospitalizaciones son mayores en los años 2013 con 68.2 (IC 95%: 64.2-72.1) casos por 100, 000 habitantes. En el periodo 2011-2015. Las tasas de incidencia en las defunciones de IRAG asociadas a influenza1.Doctor(a) en medicina y cirugía.2.Doctor(a) en Pediatría3.Nivel Básico de Epidemiologia de Campo del FETP4.MSc.Epidemiólogo del FETP, coordinador de las enfermedades Transmisibles de la unidad devigilancia de la salud, Secretaria de Salud de HondurasAutor de correspondencia: Hommer Mejía, homams2003@yahool.comRecibido: Aprobado: (J09-J18) fueron mayores en el año 2014 con 1 caso (IC 95%: 0.4-1.6) por 100 000 habitantes. La circulación por influenza comenzó a incrementarse a partir de agosto del 2011 luego en los años 2012-2015 con picos altos durante los meses de octubre y noviembre. Conclusión: La carga médica asociada a influenza representa un impacto para los servicios de salud de Honduras, siendo los grupos de población en edades extremas, los que más hospitalizaciones y muertes presentaron. Se sugiere promover la vacunación contra influenza con la composición de cepas circulantes en el país y en temporada apropiada, enfatizando en los grupos más vulnerables de la población...(AU)