RESUMO
Infectious bronchitis virus (IBV) was first isolated in Australia in 1962. Ongoing surveillance and characterization of Australian IBVs have shown that they have evolved separately from strains found throughout the rest of the world, resulting in the evolution of a range of unique strains and changes in the dominant wild-type strains, affecting tissue tropism, pathogenicity, antigenicity, and gene arrangement. Between 1961 and 1976 highly nephropathogenic genotype GI-5 and GI-6 strains, causing mortalities of 40% to 100%, predominated, while strains causing mainly respiratory disease, with lower mortality rates, have predominated since then. Since 1988, viruses belonging to two distinct and novel genotypes, GIII and GV, have been detected. The genome organization of the GIII strains has not been seen in any other gammacoronavirus. Mutations that emerged soon after the introduction of vaccination, incursion of strains with a novel lineage from unknown sources, recombination between IBVs from different genetic lineages, and gene translocations and deletions have contributed to an increasingly complex IBV population. These processes and the consequences of this variation for the biology of these viruses provide an insight into the evolution of endemic coronaviruses during their control by vaccination and may provide a better understanding of the potential for evolution of other coronaviruses, including SARS-CoV-2. Furthermore, the continuing capacity of attenuated IBV vaccines developed over 40 years ago to provide protection against viruses in the same genetic lineage provides some assurance that coronavirus vaccines developed to control other coronaviruses may continue to be effective for an extended period.
Assuntos
Evolução Biológica , Galinhas , Infecções por Coronaviridae/veterinária , Vírus da Bronquite Infecciosa/fisiologia , Doenças das Aves Domésticas/virologia , Animais , Variação Antigênica , Austrália/epidemiologia , Infecções por Coronaviridae/epidemiologia , Infecções por Coronaviridae/prevenção & controle , Infecções por Coronaviridae/virologia , Evolução Molecular , Variação Genética , Vírus da Bronquite Infecciosa/classificação , Vírus da Bronquite Infecciosa/genética , Vírus da Bronquite Infecciosa/imunologia , Fenótipo , Filogenia , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/prevenção & controle , Vacinas ViraisRESUMO
The H5N1 subtype of highly pathogenic avian influenza virus has been circulating in poultry in Indonesia since 2003 and vaccination has been used as a strategy to eradicate the disease. However, monitoring of vaccinated poultry flocks for H5N1 infection by serological means has been difficult, as vaccine antibodies are not readily distinguishable from those induced by field viruses. Therefore, a test that differentiates infected and vaccinated animals (DIVA) would be essential. Currently, no simple and specific DIVA test is available for screening of a large number of vaccinated chickens. Several epitopes on E29 domain of the haemagglutinin H5N1 subunit 2 (HA2) have recently been examined for their antigenicity and potential as possible markers for DIVA in chicken. In this study, the potential of E29 as an antigen for DIVA was evaluated in detail. Three different forms of full-length E29 peptide, a truncated E29 peptide (E15), and a recombinant E29 were compared for their ability to detect anti-E29 antibodies. Preliminary ELISA experiments using mono-specific chicken and rabbit E29 sera, and a mouse monoclonal antibody revealed that the linear E29 peptide was the most antigenic. Further examination of the E29 antigenicity in ELISA, using several sera from experimentally infected or vaccinated chickens, revealed that the full-length E29 peptide had the greatest discrimination power between infected and vaccinated chicken sera while providing the least non-specific reaction. This study demonstrates the usefulness of the HPAI H5N1 HA2 E29 epitope as a DIVA antigen in HPAI H5N1-vaccinated and -infected chickens.RESEARCH HIGHLIGHTS E29 (HA2 positions 488-516) epitope is antigenic in chickens.Antibodies to E29 are elicited following live H5N1 virus infection in chickens.E29 epitope is a potential DIVA antigen for use in ELISA.
Assuntos
Anticorpos Antivirais/sangue , Epitopos/imunologia , Hemaglutininas Virais/imunologia , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Aviária/prevenção & controle , Animais , Anticorpos Antivirais/imunologia , Antígenos Virais , Galinhas , Hemaglutininas Virais/química , Influenza Aviária/diagnóstico , Influenza Aviária/virologia , Subunidades Proteicas , VacinaçãoRESUMO
Monitoring avian influenza (AI) infection and detecting silent infection in vaccinated chickens has been challenging due to the lack of effective serological diagnostic assays to differentiate between vaccinated and infected animals. Very few studies have identified suitable proteins in AI virus that can be used in successfully differentiating infected from vaccinated animals (DIVA). An HA2 peptide: HA2 position 197-201 (HA position 488-516) described by Khurana et al. (J Virol 85(23):12455-12463, 2011), was shown to have DIVA ability by differentiating H5N1-infected human sera in ELISA. In order to explore the capacity of the HA2 protein, as a DIVA reagent in chickens, four overlapping recombinant HA2 proteins, were expressed in E. coli and tested for reaction with H5N1 sera obtained from infected and vaccinated chickens. Recombinant protein HA2_B2 (380-461) was able to generate a detectable reaction with both H5N1 infected and vaccinated chicken sera but recombinant protein HA2_B4 (483-565) reacted strongly only with sera obtained from chickens infected with live virus, confirming its suitability as a DIVA antigen. Further analysis of the HA2 using several overlapping peptides suggested that positions 380-461 and 483-565 were antigenic in mouse and chicken. This study, for the first time, identified novel antigenic epitopes on the H5N1 HA2 subunit. Two epitopes, found in the HA2 ectodomain, have never been described for AIV infection in any animal species. Also one HA2 epitope was found to have high potential as a DIVA antigen.
Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Virus da Influenza A Subtipo H5N1/imunologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Animais , Anticorpos Antivirais/imunologia , Galinhas , Mapeamento de Epitopos , Epitopos/química , Epitopos/genética , Epitopos/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Virus da Influenza A Subtipo H5N1/química , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/isolamento & purificação , CamundongosRESUMO
A peptide enzyme linked immunosorbent assay (ELISA) based on an epitope in the haemagglutinin (HA) of avian influenza virus H5N1, amino acid positions 274-288 (HA274-288) was evaluated for detection of H5N1-specific antibodies. An optimized ELISA based on the tetrameric form of the HA274-288 epitope designated MP15 gave low background with non-immune chicken sera and detected vaccinated and infected birds. The HA274-288 epitope was highly conserved in Indonesian H5N1 strains and antibody responses were detected in the majority of the vaccinated chickens regardless of the H5N1 strain used for vaccination. The HA274-288 epitope was also conserved in the majority of H5N1 strains from the neighbouring Asian region, and other H5 subtypes potentially allowing for a wider use of the MP15 ELISA in H5N1 vaccinated and infected flocks. The MP15 ELISA results correlated significantly with haemagglutination inhibition (HI) test results and test sensitivity and specificity were 87% and 92%, respectively. The MP15 ELISA titres were significantly higher than the HI titres in all immune sera allowing for sera to be tested at a single dilution of 1:400 which is of advantage in routine surveillance. The study indicated that the MP15 ELISA is potentially useful for serological detection of H5N1 vaccinated or infected poultry and to have some advantages over the standard HI test for routine monitoring of flocks' immunity after vaccination.
Assuntos
Anticorpos Antivirais/imunologia , Galinhas/virologia , Epitopos/imunologia , Virus da Influenza A Subtipo H5N1/imunologia , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Sequência de Aminoácidos , Animais , Ensaio de Imunoadsorção Enzimática/veterinária , Testes de Inibição da Hemaglutinação/veterinária , Indonésia/epidemiologia , Influenza Aviária/virologia , Aves Domésticas , Doenças das Aves Domésticas/virologia , Sensibilidade e Especificidade , Vacinação/veterináriaRESUMO
A surveillance method able to differentiate between vaccinated and infected poultry is required for those countries that practice vaccination against highly pathogenic avian influenza H5N1. The external domain of the M2 protein (M2e) of influenza virus is a potentially useful differentiating-infected from vaccinated animals (DIVA) antigen but little is known about the M2e antibody response and factors influencing its detection. In this study, the M2e antibody response was characterized in layer birds vaccinated and challenged with an Indonesian H5N1 virus isolate, using a single M2e peptide or four-branched multiple antigenic peptide form of M2e (MAP-M2e) as antigens in two separate ELISAs. Anti-M2e antibodies were absent in chicks with high level of maternal haemagglutination inhibition antibodies and also in all layers vaccinated once, twice or three times with an inactivated commercial H5N1 vaccine. In contrast, anti-M2e antibodies were detected in vaccinated layers challenged with H5N1 virus and their presence was associated with virus isolation and an increase in haemagglutination inhibition titres. The number of birds that developed M2e antibodies, as well as the strength and duration of the M2e antibody response were strongly influenced by the length of the interval between vaccination and challenge. Birds challenged at six weeks after vaccination all developed M2e antibodies by 14 days that lasted until at least 56 days after infection. In birds challenged at two weeks after vaccination, only a proportion of birds developed M2e antibodies by 14 days that lasted only until 28 days post-infection. Both single M2e peptide and MAP-M2e ELISAs had high diagnostic specificity but the diagnostic sensitivity of MAP-M2e ELISA was significantly higher and more effective in detecting M2e antibody in immune and infected birds. The results show that MAP-M2e ELISA would be useful for surveillance in countries using vaccination to control highly pathogenic avian influenza H5N1.
Assuntos
Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Galinhas/imunologia , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Aviária/imunologia , Animais , Galinhas/virologia , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Virus da Influenza A Subtipo H5N1/patogenicidade , Influenza Aviária/virologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Vacinação/veterináriaRESUMO
Pandemic influenza remains as a substantial threat to humans with a widespread panic worldwide. In contrast, seasonal (non-pandemic) has a mild non-lethal infection each year. The underlying mechanisms governing the detrimental effects of pandemic influenza are yet to be known. Transcriptomic-based network discovery and gene ontology (GO) analysis of host response to pandemic influenza, compared to seasonal influenza, can shed light on the differential mechanisms which pandemic influenza is employed during evolution. Here, using microarray data of infected ferrets with pandemic and seasonal influenza (as a model), we evaluated the possible link between altered genes after pandemic infection with activation of neuronal disorders. To this end, we utilized novel computational biology techniques including differential transcriptome analysis, network construction, GO enrichment, and GO network to investigate the underlying mechanisms of pandemic influenza infection and host interaction. In comparison to seasonal influenza, pandemic influenza differentially altered the expression of 31 genes with direct involvement in activity of central nervous system (CNS). Network topology highlighted the high interactions of IRF1, NKX2-1 and NR5A1 as well as MIR27A, MIR19A, and MIR17. TGFB2, NCOA3 and SP1 were the central transcription factors in the networks. Pandemic influenza remarkably downregulated GPM6A and GTPase. GO network demonstrated the key roles of GPM6A and GTPase in regulation of important functions such as synapse assembly and neuron projection. For the first time, we showed that besides interference with cytokine/chemokine storm and neuraminidase enzyme, H1N1 pandemic influenza is able to directly affect neuronal gene networks. The possibility of application of some key regulators such as GPM6A protein, MIR128, and MIR367 as candidate therapeutic agents is discussed. The presented approach established a new way to unravel unknown pathways in virus-associated CNS dysfunction by utilizing global transcriptomic data, network and GO analysis.
Assuntos
Redes Reguladoras de Genes , Vírus da Influenza A Subtipo H1N1 , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Infecções por Orthomyxoviridae/genética , Animais , Biologia Computacional , Citocinas/metabolismo , Modelos Animais de Doenças , Regulação para Baixo , Furões , Perfilação da Expressão Gênica , Ontologia Genética , Neuraminidase/metabolismo , Infecções por Orthomyxoviridae/epidemiologia , Infecções por Orthomyxoviridae/metabolismo , PandemiasRESUMO
The emergence of new variant strains of the poultry pathogen infectious bronchitis virus (IBV) is continually reported worldwide, owing to the labile nature of the large single-stranded RNA IBV genome. High resolution melt curve analysis previously detected a variant strain, N1/08, and the present study confirmed that this strain had emerged as a result of recombination between Australian subgroup 2 and 3 strains in the spike gene region, in a similar manner reported for turkey coronaviruses. The S1 gene for N1/08 had highest nucleotide similarity with subgroup 2 strains, which is interesting considering subgroup 2 strains have not been detected since the early 1990s. SimPlot analysis of the 7.2-kb 3' end of the N1/08 genome with the same region for other Australian reference strains identified the sites of recombination as immediately upstream and downstream of the S1 gene. A pathogenicity study in 2-week-old chickens found that N1/08 had similar pathogenicity for chicken respiratory tissues to that reported for subgroup 2 strains rather than subgroup 3 strains. The results of this study demonstrate that recombination is a mechanism utilized for the emergence of new strains of IBV, with the ability to alter strain pathogenicity in a single generation.
Assuntos
Galinhas/virologia , Infecções por Coronavirus/veterinária , Vírus da Bronquite Infecciosa/fisiologia , Doenças das Aves Domésticas/virologia , Recombinação Genética , Glicoproteína da Espícula de Coronavírus/genética , Animais , Sequência de Bases , Infecções por Coronavirus/virologia , Vírus da Bronquite Infecciosa/genética , Vírus da Bronquite Infecciosa/patogenicidade , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Análise de Sequência de DNA/veterinária , Traqueia/virologia , Tropismo Viral , VirulênciaRESUMO
Infectious bronchitis viruses (IBVs) are group III coronaviruses that infect poultry worldwide. Genetic variations, including whole-gene deletions, are key to IBV evolution. Australian subgroup 2 IBVs contain sequence insertions and multiple gene deletions that have resulted in a substantial genomic divergence from international IBVs. The genomic variations present in Australian IBVs were investigated and compared to those of another group III coronavirus, turkey coronavirus (TCoV). Open reading frames (ORFs) found throughout the genome of Australian IBVs were analogous in sequence and position to TCoV ORFs, except for ORF 4b, which appeared to be translocated to a different position in the subgroup 2 strains. Subgroup 2 strains were previously reported to lack genes 3a, 3b and 5a, with some also lacking 5b. Of these, however, genes 3b and 5b were found to be present but contained various mutations that may affect transcription. In this study, it was found that subgroup 2 IBVs have undergone a more substantial genomic rearrangements than previously thought.
Assuntos
Genoma Viral , Vírus da Bronquite Infecciosa/genética , Sequência de Aminoácidos , Animais , Austrália , Sequência de Bases , Coronavirus do Peru/classificação , Coronavirus do Peru/genética , DNA Viral/genética , Evolução Molecular , Deleção de Genes , Genes Virais , Interações Hidrofóbicas e Hidrofílicas , Vírus da Bronquite Infecciosa/classificação , Dados de Sequência Molecular , Fases de Leitura Aberta , Aves Domésticas/virologia , Homologia de Sequência de Aminoácidos , Especificidade da Espécie , Translocação Genética , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Estruturais Virais/química , Proteínas Estruturais Virais/genéticaRESUMO
New variants of infectious bronchitis virus (IBV) have emerged in Australia despite its geographical isolation and intensive vaccination programs. In the present study, the 3' terminal 7.2 kb of the genome of a recently isolated variant of IBV (N1/03) was sequenced and compared with the sequences of classical and novel strains of IBV, the two main groups of these viruses in Australia. The comparison revealed that recombination between classical and novel IBVs was responsible for the emergence of the new variant. It was concluded that novel IBVs, which have not been detected since 1993, and which are phylogenically more distant from classical IBVs than turkey coronaviruses, might still be circulating and contributing to the evolution of IBV in Australia.
Assuntos
Infecções por Coronavirus/veterinária , Vírus da Bronquite Infecciosa/classificação , Vírus da Bronquite Infecciosa/genética , Doenças das Aves Domésticas/virologia , Recombinação Genética , Animais , Austrália , Galinhas , Análise por Conglomerados , Infecções por Coronavirus/virologia , Vírus da Bronquite Infecciosa/isolamento & purificação , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Homologia de SequênciaRESUMO
Here, we report two genomes of newly emerged strains of Newcastle disease virus (NDV), Chicken/Indonesia/Tangerang/004WJ/14 and Chicken/Indonesia/VD/003WJ/11, from disease outbreaks in chickens in Indonesia. Phylogenetic study results of the fusion (F) protein's gene-coding sequences of different genotypes of NDV revealed that these two strains belong to genotype VII.1 in the class II cluster of avian paramyxoviruses.
RESUMO
The genomes of two newly emerged Newcastle disease virus strains, chicken/Indonesia/Mega/001WJ/2013 and chicken/Indonesia/Cimanglid/002WJ/2015, from disease outbreaks in chickens in Indonesia are reported. Phylogenetic analysis of different genotypes of Newcastle disease virus using the F gene coding sequences suggests that these two strains belong to genotype VII.2, in class II of avian paramyxoviruses.
RESUMO
A number of novel infectious bronchitis viruses (IBVs) were previously identified in commercial poultry in Australia, where they caused significant economic losses. Since there has been only limited characterization of these viruses, we investigated the genomic and phenotypic differences between these novel IBVs and other, classical IBVs. The 3' 7.5 kb of the genomes of 17 Australian IBV strains were sequenced, and growth properties of 6 of the strains were compared. Comparison of sequences of the genes coding for structural and nonstructural proteins revealed the existence of two IBV genotypes: classical and novel. The genomic organization of the classical IBVs was typical of those of other group III coronaviruses: 5'-Pol-S-3a-3b-E-M-5a-5b-N-untranslated region (UTR)-3'. However, the novel IBV genotype lacked either all or most of the genes coding for nonstructural proteins at the 3' end of the genome and had a unique open reading frame, X1. The gene order was either 5'-Pol-S-X1-E-M-N-UTR-3' or 5'-Pol-S-X1-E-M-5b-N-UTR-3'. Phenotypically, novel and classical IBVs also differed; novel IBVs grew at a slower rate and reached lower titers in vitro and in vivo and were markedly less immunogenic in chicks. Although the novel IBVs induced histopathological lesions in the tracheas of infected chicks that were comparable to those induced by classical strains, they did not induce lesions in the kidneys. This study has demonstrated for the first time the existence of a naturally occurring IBV genotype devoid of some of the genes coding for nonstructural proteins and has also indicated that all of the accessory genes are dispensable for the growth of IBV and that such viruses are able to cause clinical disease and economic loss. The phylogenic differences between these novel IBVs and other avian coronaviruses suggest a reservoir host distinct from domestic poultry.
Assuntos
Infecções por Coronavirus/veterinária , Vírus da Bronquite Infecciosa/genética , Vírus da Bronquite Infecciosa/imunologia , Doenças das Aves Domésticas/virologia , Proteínas Virais/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Embrião de Galinha , Infecções por Coronavirus/virologia , Evolução Molecular , Genes Virais , Genoma Viral/genética , Vírus da Bronquite Infecciosa/classificação , Dados de Sequência Molecular , Filogenia , Análise de Sequência de RNARESUMO
Infectious bronchitis virus (IBV) is a coronavirus that causes upper respiratory, renal and/or reproductive diseases with high morbidity in poultry. Classification of IBV is important for implementation of vaccination strategies to control the disease in commercial poultry. Currently, the lengthy process of sequence analysis of the IBV S1 gene is considered the gold standard for IBV strain identification, with a high nucleotide identity (e.g. > or =95%) indicating related strains. However, this gene has a high propensity to mutate and/or undergo recombination, and alone it may not be reliable for strain identification. A real-time polymerase chain reaction (RT-PCR) combined with high-resolution melt (HRM) curve analysis was developed based on the 3'UTR of IBV for rapid detection and classification of IBV from commercial poultry. HRM curves generated from 230 to 435-bp PCR products of several IBV strains were subjected to further analysis using a mathematical model also developed during this study. It was shown that a combination of HRM curve analysis and the mathematical model could reliably group 189 out of 190 comparisons of pairs of IBV strains in accordance with their 3'UTR and S1 gene identities. The newly developed RT-PCR/HRM curve analysis model could detect and rapidly identify novel and vaccine-related IBV strains, as confirmed by S1 gene and 3'UTR nucleotide sequences. This model is a rapid, reliable, accurate and non-subjective system for detection of IBVs in poultry flocks.
Assuntos
Infecções por Coronavirus/veterinária , Vírus da Bronquite Infecciosa/classificação , Vírus da Bronquite Infecciosa/isolamento & purificação , Doenças das Aves Domésticas/virologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Temperatura de Transição , Regiões 3' não Traduzidas , Animais , Sequência de Bases , Infecções por Coronavirus/virologia , Vírus da Bronquite Infecciosa/genética , Modelos Teóricos , Dados de Sequência Molecular , Aves Domésticas , RNA Viral/genética , Alinhamento de SequênciaRESUMO
Whilst the serological responses of poultry following vaccination against highly pathogenic avian influenza H5N1 has been extensively investigated under laboratory conditions, there have been fewer studies conducted in the field. This applies particularly to the endemically infected countries routinely practicing vaccination, where the combination of multiple circulating clades and/or the use of vaccines with different seed strains makes the design and interpretation of field studies especially problematic. To address this for the particular situation of layer hens in the small to medium commercial sector in Indonesia, we developed a sampling regime before and after the vaccination given to point-of-lay pullets, and assessed serological response with a panel of test antigens. This confirmed that high titres were induced in those birds vaccinated with locally produced homologous H5N1 vaccines administered two or more times, but in flocks using imported heterologous H5N2 vaccines median titres were significantly lower, and unlikely to provide protection throughout the production cycle, without additional vaccination. Comparing the HI responses against the panel of antigens enabled the detection of the flock's exposure to different vaccine antigens, and made possible the detection of mislabelled vaccine seed strains. Furthermore, we show that test antigens need not be exactly matched to assess sero-protection in well vaccinated birds. Finally our study suggests that the POL vaccination serves as a useful reference point for following cohorts of layers throughout their production cycle, and thus enabling robust vaccination field effectiveness studies.
RESUMO
Although vaccination of poultry for control of highly pathogenic avian influenza virus (HPAIV) H5N1 has been practiced during the last decade in several countries, its effectiveness under field conditions remains largely unquantified. Effective HPAI vaccination is however essential in preventing incursions, silent infections and generation of new H5N1 antigenic variants. The objective of this study was to asses the level and duration of vaccine induced immunity in commercial layers in Indonesia. Titres of H5N1 haemagglutination inhibition (HI) antibodies were followed in individual birds from sixteen flocks, age 18-68 week old (wo). The study revealed that H5N1 vaccination had highly variable outcome, including vaccination failures, and was largely ineffective in providing long lasting protective immunity. Flocks were vaccinated with seven different vaccines, administer at various times that could be grouped into three regimes: In regime A, flocks (n = 8) were vaccinated two or three times before 19 wo; in regime B (n = 2), two times before and once after 19 wo; and in regime C (n = 6) three to four times before and two to three times after 19 wo. HI titres in regime C birds were significantly higher during the entire observation period in comparison to titres of regime A or B birds, which also differed significantly from each other. The HI titres of individual birds in each flock differed significantly from birds in other flocks, indicating that the effectiveness of field vaccination was highly variable and farm related. Protective HI titres of >4log2, were present in the majority of flocks at 18 wo, declined thereafter at variable rate and only two regime C flocks had protective HI titres at 68 wo. Laboratory challenge with HPAIV H5N1 of birds from regime A and C flocks confirmed that protective immunity differed significantly between flocks vaccinated by these two regimes. The study revealed that effectiveness of the currently applied H5N1 vaccination could be improved and measures to achieve this are discussed.
Assuntos
Galinhas , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Criação de Animais Domésticos , Animais , Anticorpos Antivirais/sangue , Galinhas/imunologia , Galinhas/virologia , Testes de Inibição da Hemaglutinação , Indonésia , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/imunologia , Influenza Aviária/virologia , Estudos Longitudinais , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/virologia , Estudos Prospectivos , Falha de TratamentoRESUMO
In countries where highly pathogenic avian influenza virus (HPAIV) H5N1 is endemic and controlled by vaccination, post-vaccination serological monitoring is essential to differentiate vaccinated poultry from those that are infected. The objectives of this study were to validate two experimental ELISAs that detect antibodies raised against the M2e protein of avian influenza virus that can be used for DIVA purposes. Results from the sM2e and tM2e ELISAs were compared with other conventional tests for the detection of H5N1influenza virus (virus isolation and RT-PCR) using samples collected from 16 commercial flocks in Indonesia. These comprised vaccinated layers aged between 18 and 68 weeks old that were sampled at ten-weekly intervals. A small number of sera were positive in sM2e and tM2e ELISA, 14 (0.6%) and 17 (0.7%) respectively, with low OD420 (0.1-0.3), but only 4 sera were positive in both tests. At the flock level, the incidence of M2e positive sera was low (4%), well below previously established minimum of 40% for an HPAIV H5N1-infected flock. Conventional M and H5 gene RT-PCRs indicated that none of 16 flocks were infected at any time during the study. No virus was isolated from any of the 480 pooled swab samples, except from one, for which the combined data analysis suggest to be the result of a laboratory cross-contamination. Clinical disease, mortalities or reduction in production performance, indicative of field H5N1 challenge, were not observed either in any of the flocks. Birds from two surveyed flocks, challenged in the laboratory with an Indonesian HPAIV H5N1 developed M2e antibodies in 50% and 55% of surviving birds with OD420 in the range of 0.35-1.47 in tM2e ELISA, confirming the validity of the criteria established for use of M2e ELISA for DIVA purposes. Overall these results showed that the tM2e ELISA could be a useful monitoring tool to ascertain freedom from H5N1 infections in vaccinated commercial poultry.
Assuntos
Anticorpos Antivirais/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Vigilância Imunológica , Virus da Influenza A Subtipo H5N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Aviária/imunologia , Animais , Indonésia/epidemiologia , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/patogenicidade , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/epidemiologia , Influenza Aviária/prevenção & controle , Aves Domésticas/imunologia , Aves Domésticas/virologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/virologia , Vacinação/veterináriaRESUMO
Vaccination is becoming a more acceptable option in the effort to eradicate avian influenza viruses (AIV) from commercial poultry, especially in countries where AIV is endemic. The main concern surrounding this option has been the inability of the conventional serological tests to differentiate antibodies produced due to vaccination from antibodies produced in response to virus infection. In attempts to address this issue, at least six strategies have been formulated, aiming to differentiate infected from vaccinated animals (DIVA), namely (i) sentinel birds, (ii) subunit vaccine, (iii) heterologous neuraminidase (NA), (iv) nonstructural 1 (NS1) protein, (v) matrix 2 ectodomain (M2e) protein, and (vi) haemagglutinin subunit 2 (HA2) glycoprotein. This short review briefly discusses the strengths and limitations of these DIVA strategies, together with the feasibility and practicality of the options as a part of the surveillance program directed toward the eventual eradication of AIV from poultry in countries where highly pathogenic avian influenza is endemic.
Assuntos
Anticorpos Antivirais/sangue , Galinhas/sangue , Doenças Endêmicas/prevenção & controle , Monitoramento Epidemiológico/veterinária , Vírus da Influenza A/imunologia , Influenza Aviária/prevenção & controle , Animais , Galinhas/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/sangue , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/patogenicidade , Vacinas contra Influenza/uso terapêutico , Influenza Aviária/epidemiologia , Influenza Aviária/imunologia , Influenza Aviária/virologia , Neuraminidase/sangue , Espécies Sentinelas/sangue , Espécies Sentinelas/imunologia , Testes Sorológicos , Vacinação/métodos , Proteínas não Estruturais Virais/sangueRESUMO
To help guide surveillance and control of highly pathogenic avian influenza subtype H5N1 (H5N1-HPAI), the Food and Agriculture Organization of the United Nations in 2004 devised a poultry farm classification system based on a combination of production and biosecurity practices. Four "Sectors" were defined, and this scheme has been widely adopted within Indonesia to guide national surveillance and control strategies. Nevertheless, little detailed research into the robustness of this classification system has been conducted, particularly as it relates to independent, small to medium-sized commercial poultry farms (Sector 3). Through an analysis of questionnaire data collected as part of a survey of layer farms in western and central Java, all of which were classified as Sector 3 by local veterinarians, we provide benchmark data on what defines this sector. A multivariate analysis of the dataset, using hierarchical cluster analysis, identified three groupings of the farms, which were defined by a combination of production-and biosecurity-related variables, particularly those related to farm size and (the lack of) washing and disinfection practices. Nevertheless, the relationship between production-related variables and positive biosecurity practices was poor, and larger farms did not have an overall higher total biosecurity score than small or medium-sized ones. Further research is required to define the properties of poultry farms in Indonesia that are most closely related to effective biosecurity and the prevention of H5N1-HPAI.