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1.
Rev Sci Tech ; 38(1): 225-237, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31564728

RESUMO

In 2016-2017, the H5N8 strain of highly pathogenic avian influenza (HPAI) spread worldwide and Uganda reported the first occurrence of the disease in its poultry and wild birds. Genetic analysis revealed that the virus clusters with 2.3.4.4 group B strains from birds in central and southern Asia, and thus forms part of the 2.3.4.4 group B clade. Since Uganda is in the path of two major migratory bird flyways, it is likely that infected migratory wild birds played a crucial role in the introduction of H5N8 HPAI viruses into Uganda. The outbreaks happened in the districts of Wakiso, Masaka and Kalangala and affected domestic and wild birds. A One Health Multisectoral Coordination Committee, consisting of a National Task Force, Technical Working Groups and District Disaster Management Committees, was immediately activated to coordinate the preparedness and response efforts to control the disease. In all the affected districts, surveillance was intensified on both domestic and wild birds; biosecurity measures were increased; and movement controls, culling, cleaning, disinfection and safe disposal of carcasses were implemented. Awareness of the disease was raised through education materials, leaflets and brochures distributed to farmers. Finally, Uganda successfully controlled the H5N8 outbreak, using its national preparedness and response mechanisms and through collaboration with international partners. The emergence and spread of this virus strain in Uganda and other parts of Africa poses a significant threat to the poultry industry and food security.


Assuntos
Animais Selvagens , Surtos de Doenças , Vírus da Influenza A Subtipo H5N8 , Influenza Aviária , Migração Animal , Animais , Ásia , Aves , Surtos de Doenças/prevenção & controle , Humanos , Influenza Aviária/prevenção & controle , Uganda
2.
Int J Nanomedicine ; 14: 7533-7548, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31571862

RESUMO

Background: The influenza A virus (IAV) is known for its high variability and poses a huge threat to the health of humans and animals. Pigs play a central role in the cross-species reassortment of IAV. Ectodomain of matrix protein 2 (M2e) is the most conserved protective antigen in IAV and can be used to develop nanovaccines through nanoparticles displaying to increase its immunogenicity. However, the high immunogenicity of nanoparticles can cause the risk of off-target immune response, and excess unwanted antibodies may interfere with the protective efficacy of M2e-specific antibodies. Therefore, it is necessary to select reasonable nanoparticles to make full use of antibodies against nanoparticles while increasing the level of M2e-specific antibodies. Porcine circovirus type 2 (PCV2) is the most susceptible virus in pigs and can promote IAV infection. It is meaningful to develop a vaccine that can simultaneously control swine influenza virus (SIV) and PCV2. Methods: In the present study, M2e of different copy numbers were inserted into the capsid (Cap) protein of PCV2 and expressed in Escherichia coli to form self-assembled chimeric virus-like particles (VLPs) nanovaccine. BALB/c mice and pigs were immunized with these nanovaccines to explore optimal anti-IAV and anti-PCV2 immunity. Results: Cap is capable of carrying at least 81 amino acid residues (three copies of M2e) at its C-terminal without impairing VLPs formation. Cap-3M2e VLPs induced the highest levels of M2e-specific immune responses, conferring protection against lethal challenge of IAVs from different species and induced specific immune responses consistent with PCV2 commercial vaccines in mice. In addition, Cap-3M2e VLPs induced high levels of M2e-specific antibodies and PCV2-specific neutralizing antibodies in pigs. Conclusion: Cap-3M2e VLP is an economical and promising bivalent nanovaccine, which provides dual protection against IAV and PCV2.


Assuntos
Circovirus/imunologia , Vírus da Influenza A/imunologia , Nanopartículas/uso terapêutico , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Vacinas Virais/imunologia , Animais , Anticorpos Antivirais/imunologia , Formação de Anticorpos/imunologia , Especificidade de Anticorpos/imunologia , Aves/virologia , Proteínas do Capsídeo/química , Proliferação de Células , Citocinas/metabolismo , Cães , Feminino , Humanos , Imunidade Humoral , Influenza Aviária/imunologia , Influenza Aviária/prevenção & controle , Influenza Aviária/virologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Linfócitos/citologia , Células Madin Darby de Rim Canino , Camundongos Endogâmicos BALB C , Testes de Neutralização , Proteínas Recombinantes/isolamento & purificação , Suínos , Vírion/imunologia , Vírion/ultraestrutura
3.
Acta Biochim Pol ; 66(3): 329-336, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31531422

RESUMO

The potential emergence of deadly pandemic influenza viruses is unpredictable and most have emerged with no forewarning. The distinct epidemiological and pathological patterns of the Spanish (H1N1), pandemic-2009 (H1N1), and avian influenza (H5N1), known as bird flu, viruses may allow us to develop a 'template' for possible emergence of devastating pandemic strains. Here, we provide a detailed molecular dissection of the structural and nonstructural proteins of this triad of viruses. GenBank data for three representative strains were analyzed to determine the polymorphic amino acids, genetic distances, and isoelectric points, hydrophobicity plot, and protein modeling of various proteins. We propose that the most devastating pandemic strains may have full-length PB1-F2 protein with unique residues, highly cleavable HA, and a basic NS1. Any newly emerging strain should be compared with these three strains, so that resources can be directed appropriately.


Assuntos
Simulação por Computador , Vírus da Influenza A Subtipo H1N1/genética , Virus da Influenza A Subtipo H5N1/genética , Influenza Aviária/virologia , Influenza Humana/virologia , Proteínas Virais/química , Animais , Aves , Transmissão de Doença Infecciosa , Genoma Viral , Humanos , Influenza Pandêmica, 1918-1919 , Vacinas contra Influenza , Influenza Aviária/epidemiologia , Influenza Aviária/prevenção & controle , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Pandemias , Conformação Proteica em alfa-Hélice , Proteínas Virais/genética
4.
Protein Pept Lett ; 26(12): 940-948, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31362650

RESUMO

BACKGROUND: Bursa of Fabricius plays the vital functions on B cell development and antibody production in poultry. The bursal-derived peptide plays the essential roles on avian immature B cell development. OBJECTIVES: Here we explored the functions of the recently reported bursal nonapeptide (BP9) on the antibody production and the molecular basis of BP9 on avian immature B cell. METHODS: Chicken were twice immunized with Avian Influenza Virus (AIV) inactivated vaccine plus with BP9 at three dosages, respectively. On two weeks after the second immunization, sera samples were collected from all experimental groups to measure AIV-specific Agglutination Inhibition (HI) antibody titers. Also, on 7th day after the second immunization, spleen lymphocytes were isolated from the immunized chicken to detect the lymphocyte viabilities. DT40 cells were treated with BP9 from 0.02 to 2 µg/mL for 4 and 20h to detect sIgM mRNA levels, and total RNAs from BP9-treated DT40 cells were collected to investigate the gene expression profiles of DT40 cells, and to analyze the enriched pathways and functional biological processes. Finally, nine gene expressions were validated with quantitative PCR (qPCR). RESULTS: Our investigation proved the strong regulatory roles of BP9 on AIV-specific HI antibody titers and lymphocyte viabilities. BP9 promoted sIgM mRNA levels in DT40 cells, and upregulated 598 gene expressions and downregulated 395 gene expressions in DT40 cells with 0.2µg/mL BP9 treatment. Moreover, our findings verified the significantly enriched six pathways and various the biological functional processes of BP9 on avian immature B cell. Also, we found eight signaling pathways in the enriched biological processes of BP9-treated DT40 cells, and the expressions of nine selected genes with qPCR were identical to that of microarray data. CONCLUSION: BP9 promoted the antibody production in the 21-old-day chicken immunization, and stimulated the sIgM expression in DT40 cells. Furthermore, we analyzed the gene expression profile and immune-related biological processes of DT40 cells treated with BP9, which provided some new insights into the mechanism on immature B cell development, and provided important references for adjuvant development on vaccine improvement and clinical application.


Assuntos
Bolsa de Fabricius/química , Vacinas contra Influenza/imunologia , Influenza Aviária/prevenção & controle , Oligopeptídeos/imunologia , Células Precursoras de Linfócitos B/imunologia , Adjuvantes Imunológicos/farmacologia , Animais , Formação de Anticorpos , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Galinhas , Humanos , Imunização , Imunoglobulina M/metabolismo , Influenza Aviária/imunologia , Influenza Aviária/virologia , Oligopeptídeos/química , Células Precursoras de Linfócitos B/citologia , Células Precursoras de Linfócitos B/efeitos dos fármacos , Vacinas de Produtos Inativados/imunologia
5.
Comp Immunol Microbiol Infect Dis ; 65: 165-175, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31300109

RESUMO

Avian influenza vaccines are commonly used in the poultry industry, and some medicinal plants can increase the efficacy of such vaccines. The objective of this study was to evaluate the effect of Immulant® (IMU) (a commercial product based on Echinacea and Nigella sativa) on stress induced by dexamethasone (DEX) in chickens vaccinated (VAC) against the H9N2 avian influenza virus (AIV-H9N2). Seven experimental groups were included: the negative control, VAC, DEX, VAC + DEX, VAC + DEX + IMU, VAC + IMU and IMU groups. The vaccinated chickens (at 10 days of age) were injected daily with DEX for three days pre-vaccination and for three days pre-challenge and orally administered 1% IMU for 6 weeks post-vaccination (PV). The chickens were then challenged intranasally with AIV-H9N2 at 28 days PV. Serum, blood, tracheal and cloacal swabs and tissue samples were collected in the 1st and 4th weeks PV and at different time points post-challenge. The results showed significant changes (P ≤ 0.05) in oxidative stress and antioxidant biomarkers (malondialdehyde, nitric oxide and reduced glutathione), haematological and immunological parameters, final live weights, relative organ weights and histopathological lesions between the VAC+DEX group and the VAC group. Moreover, IMU significantly increased protection rates post-challenge, HI antibody titers and heterophil phagocytic activity and decreased DEX-induced stress and virus shedding titers. In conclusion, oral administration of 1% IMU for six weeks can enhance the immune response after AI-H9N2 vaccination and reduce the pathogenicity of infection in stressed chickens.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Galinhas/imunologia , Echinacea/química , Vírus da Influenza A Subtipo H9N2/patogenicidade , Vacinas contra Influenza/imunologia , Nigella sativa/química , Adjuvantes Imunológicos/química , Animais , Anticorpos Antivirais/sangue , Dexametasona/administração & dosagem , Imunossupressão , Influenza Aviária/prevenção & controle , Influenza Aviária/virologia , Aves Domésticas , Estresse Fisiológico , Virulência , Eliminação de Partículas Virais
6.
Zoonoses Public Health ; 66(6): 647-654, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31215154

RESUMO

Poultry farmers faced dual risk when mutant avian influenza (AI) virus showed the zoonotic characteristics. A/H5N1 and A/H7N9 were two dominant AI virus strains that have captured the attention of the public over the years for they have been reported to bring about greater loss to poultry and human, respectively. Previous studies mainly used quantitative methods investigating either the means that poultry farmers adopted for protecting their poultry against A/H5N1 infection or the poultry farmers' self-protective behaviours against A/H7N9 infection. We sought insights into the underlying factors influencing Chinese poultry farmers' protective behaviours in response to the dual risk of AI by a qualitative way. Semi-structured in-depth interviews were conducted with 25 Chinese chicken farmers recruited by purposive sampling between November 2016 and May 2017, the peak season of AI. All interviews were audio-taped, transcribed and analysed using a grounded theory approach. From participants' experiences, we revealed five main themes: Measures adopted for protecting poultry and farmers, Emotional response to the AI epidemic, Perceived risk of AI, Perceived effectiveness of the preventive measures adopted and Perceived self-efficacy to take preventive measures. The information of AI outbreak directly triggered Chinese chicken farmers' emotional response and thereafter preventive actions. Compared to the perceived risk of poultry infection with A/H5N1 which mainly connected to economic loss, participants perceived much lower risk of human infection with A/H7N9. AI epidemic information played a key role triggering poultry farmers' response behaviours. Chinese poultry farmers weighted more attention on the risk of poultry infection which was highly associated with economic losses. The government should build and improve an early AI warning and information transmission network to poultry farmers. Further reinforcement of related self-protective and preventive knowledge training towards poultry farmers is necessary.


Assuntos
Galinhas , Fazendeiros , Influenza Aviária/prevenção & controle , Influenza Humana/virologia , Zoonoses , Adulto , Animais , China , Feminino , Humanos , Virus da Influenza A Subtipo H5N1 , Subtipo H7N9 do Vírus da Influenza A , Influenza Aviária/economia , Influenza Aviária/virologia , Masculino , Pessoa de Meia-Idade , Mutação , Fatores de Risco
7.
Vet Microbiol ; 234: 77-82, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31213275

RESUMO

Control of currently circulating re-assorted low-pathogenicity avian influenza (LPAI) H9N2 is a major concern for both animal and human health. Thus, an improved LPAI H9N2 vaccination strategy is needed to induce complete immunity in chickens against LPAI H9N2 virus strains. Cytokines play a crucial role in mounting both the type and extent of an immune response generated following infection with a pathogen or after vaccination. To improve the efficacy of inactivated LPAI H9N2 vaccine, prokaryotic expression recombination chicken interferon-α (rchIFN-α) was used as vaccine adjuvant.In this study chIFN-α was used as adjuvant in inactivated AI H9N2 vaccine, modulated the immune response of chickens against the vaccine antigen through enhanced humoral and Th1-biased cell-mediated immunity, compared to chickens that received single AI H9N2 vaccine. To further test the protective efficacy of this improved vaccination regimen, immunized chickens were challenged with a high dose of LPAI H9N2 virus. Combined administration rchIFN-α showed markedly enhanced protection compared to single administration of the vaccine, as determined by mortality, clinical severity, and feed and water intake. This enhancement of protective immunity was further confirmed by reduced rectal shedding and replication of AIV H9N2 in challenged chickens. Our results indicate the value of combined administration of rchIFN-α to generate an effective immunization strategy in chickens against LPAI H9N2.


Assuntos
Imunogenicidade da Vacina , Vacinas contra Influenza/imunologia , Influenza Aviária/prevenção & controle , Interferon-alfa/genética , Adjuvantes Imunológicos , Animais , Anticorpos Antivirais/sangue , Galinhas , Imunidade Celular , Imunidade Humoral , Vírus da Influenza A Subtipo H9N2/imunologia , Vacinas contra Influenza/genética , Influenza Aviária/imunologia , Interferon-alfa/imunologia , Organismos Livres de Patógenos Específicos , Vacinas de Produtos Inativados/genética , Vacinas de Produtos Inativados/imunologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia , Eliminação de Partículas Virais
8.
BMC Vet Res ; 15(1): 147, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088548

RESUMO

BACKGROUND: Avian influenza (AI) is an infectious viral disease that affects several species and has zoonotic potential. Due to its associated health and economic repercussions, minimizing AI outbreaks is important. However, most control measures are generic and mostly target pathways important for the conventional poultry farms producing chickens, turkeys, and eggs and may not target other pathways that may be specific to the upland game bird sector. The goal of this study is to provide evidence to support the development of novel strategies for sector-specific AI control by comparing and contrasting practices and potential pathways for spread in upland game bird farms with those for conventional poultry farms in the United States. Farm practices and processes, seasonality of activities, geographic location and inter-farm distance were analyzed across the sectors. All the identified differences were framed and discussed in the context of their associated pathways for virus introduction into the farm and subsequent between-farm spread. RESULTS: Differences stemming from production systems and seasonality, inter-farm distance and farm densities were evident and these could influence both fomite-mediated and local-area spread risks. Upland game bird farms operate under a single, independent owner rather than being contracted with or owned by a company with other farms as is the case with conventional poultry. The seasonal marketing of upland game birds, largely driven by hunting seasons, implies that movements are seasonal and customer-vendor dynamics vary between industry groups. Farm location analysis revealed that, on average, an upland game bird premises was 15.42 km away from the nearest neighboring premises with birds compared to 3.74 km for turkey premises. Compared to turkey premises, the average poultry farm density in a radius of 10 km of an upland game bird premises was less than a half, and turkey premises were 3.8 times (43.5% compared with 11.5%) more likely to fall within a control area during the 2015 Minnesota outbreak. CONCLUSIONS: We conclude that the existing differences in the seasonality of production, isolated geographic location and epidemiological seclusion of farms influence AI spread dynamics and therefore disease control measures should be informed by these and other factors to achieve success.


Assuntos
Criação de Animais Domésticos/métodos , Galliformes , Vírus da Influenza A , Influenza Aviária/epidemiologia , Animais , Surtos de Doenças , Geografia , Influenza Aviária/prevenção & controle , Influenza Aviária/transmissão , Estações do Ano , Estados Unidos
9.
Arch Virol ; 164(7): 1793-1803, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31079211

RESUMO

Numerous studies have shown that immunostimulatory complexes containing Quil-A saponin and various antigens are effective in stimulating the immune response and can be used as vaccine preparations for animals and humans. However, Quil-A saponin possesses toxicity and haemolytic activity. In the present work, a saponin-containing preparation named "Glabilox" was isolated from the roots of a Glycyrrhiza glabra L. plant by high-performance liquid chromatography (HPLC). The results showed that Glabilox has no toxicity or haemolytic activity and can form stable immunostimulatory complexes. Subcutaneous immunization of mice with an immunostimulating complex containing Glabilox and H7N1 influenza virus antigens stimulated high levels of humoral and cellular immunity. Vaccination of chickens with the same immunostimulating complex protected 100% of the animals after experimental infection with a homologous virus. Comparative studies showed that the immunogenic and protective activity of immunostimulatory complexes containing Quil-A and immunostimulatory complexes containing Glabilox are comparable to each other. The results of these studies indicated that Glycyrrhiza glabra saponins show great promise as safe and effective adjuvants.


Assuntos
Adjuvantes Imunológicos/farmacologia , Anticorpos Antivirais/sangue , Antígenos Virais/imunologia , Glycyrrhiza/imunologia , Vírus da Influenza A Subtipo H7N1/imunologia , Influenza Aviária/prevenção & controle , Animais , Linhagem Celular , Embrião de Galinha , Galinhas , Cães , Glicoproteínas/imunologia , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Influenza Aviária/imunologia , Lipídeos/imunologia , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos BALB C , Raízes de Plantas/imunologia , Saponinas de Quilaia/imunologia , Saponinas/imunologia , Vacinação
10.
Prev Vet Med ; 167: 25-31, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31027717

RESUMO

The implementation of biosecurity measures among farmers is the first line of defense against highly pathogenic avian influenza (HPAI) on poultry farms. Yet much less is known about the association between HPAI outbreak information sources, farmers' risk perception and their adoption of biosecurity behaviors (BBs). To bridge this gap, a survey (n = 426) was conducted to measure the relationship between these factors among poultry farmers in the Chinese provinces of Jiangsu and Anhui. The data reveal that farmers use multiple information sources to obtain information about HPAI outbreaks. Multivariate regression shows that HPAI outbreak information disseminated through business networks is associated with reported adoption of BBs, while farm size and ease of access to a veterinary clinic are associated with both higher risk perception and increased BBs. Moreover, increased BBs are associated with farmers who maintain stable production and sales contractual relationships with poultry product processing and marketing enterprises. The findings of this research will allow authorities to more effectively disseminate HPAI information to poultry farmers through business networks.


Assuntos
Criação de Animais Domésticos , Controle de Doenças Transmissíveis/métodos , Surtos de Doenças/veterinária , Influenza Aviária/prevenção & controle , Aves Domésticas , Adulto , Animais , China/epidemiologia , Coleta de Dados , Surtos de Doenças/prevenção & controle , Feminino , Humanos , Influenza Aviária/epidemiologia , Masculino , Pessoa de Meia-Idade , Percepção , Fatores de Risco
11.
Protein Pept Lett ; 26(7): 542-549, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30950342

RESUMO

BACKGROUND: Bursa of Fabricius is the acknowledged central humoral immune organ. The bursal-derived peptides play the important roles on the immature B cell development and antibody production. OBJECTIVES: Here we explored the functions of the new isolated bursal hexapeptide and pentapeptide on the humoral, cellular immune response and antigen presentation to Avian Influenza Virus (AIV) vaccine in mice immunization. METHODS: The bursa extract samples were purified following RP HPLC method, and were analyzed with MS/MS to identify the amino acid sequences. Mice were twice subcutaneously injected with AIV inactivated vaccine plus with two new isolated bursal peptides at three dosages, respectively. On two weeks after the second immunization, sera samples were collected from the immunized mice to measure AIV-specific IgG antibody levels and HI antibody titers. Also, on 7th day after the second immunization, lymphocytes were isolated from the immunized mice to detect T cell subtype and lymphocyte viabilities, and the expressions of co-stimulatory molecule on dendritic cells in the immunized mice. RESULTS: Two new bursal hexapeptide and pentapeptide with amino acid sequences KGNRVY and MPPTH were isolated, respectively. Our investigation proved the strong regulatory roles of bursal hexapeptide on AIV-specific IgG levels and HI antibody titers, and lymphocyte viabilities, and the significant increased T cells subpopulation and expressions of MHCII molecule on dendritic cells in the immunized mice. Moreover, our findings verified the significantly enhanced AIV-specific IgG antibody and HI titers, and the strong increased T cell subpopulation and expressions of CD40 molecule on dendritic cells in the mice immunized with AIV vaccine and bursal pentapeptide. CONCLUSION: We isolated and identified two new hexapeptide and pentapeptide from bursa, and proved that these two bursal peptides effectively induced the AIV-specific antibody, T cell and antigen presentation immune responses, which provided an experimental basis for the further clinical application of the bursal derived active peptide on the vaccine improvement.


Assuntos
Bolsa de Fabricius/química , Vírus da Influenza A Subtipo H9N2/imunologia , Vacinas contra Influenza/imunologia , Oligopeptídeos/química , Animais , Anticorpos/metabolismo , Formação de Anticorpos , Bolsa de Fabricius/imunologia , Antígenos CD40/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Galinhas , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Feminino , Imunidade Humoral , Influenza Aviária/prevenção & controle , Influenza Aviária/virologia , Camundongos Endogâmicos BALB C , Oligopeptídeos/imunologia , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacos
12.
Avian Pathol ; 48(4): 371-381, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30961360

RESUMO

The efficacies of an oil adjuvanted-inactivated reverse genetics-derived H5 avian influenza virus (AIV) vaccine and an alphavirus replicon RNA particle (RP) AIV vaccine were evaluated in commercial Leghorn chickens. Challenge utilized A/turkey/MN/12582/2015, an isolate representing the U.S. H5N2 Clade 2.3.4.4 responsible for the 2015 highly pathogenic avian influenza (HPAI) epornitic in commercial poultry the United States. As part of a long-term, 36-week study, chickens were challenged at seven weeks of age after receiving a single vaccination, at 18 weeks of age following a vaccine prime-single boost, and at 36 weeks of age after a prime- double-boost. All vaccine programmes reduced virus oropharyngeal and cloacal shedding and mortality compared to the non-vaccinated control birds; however, chickens receiving at least one administration of the RP vaccine generally had diminished viral shedding especially from the cloacal swabbings. A detectable serum antibody response and protection were observed through 18 weeks post-vaccination. Our data suggest that, in conjunction with a comprehensive eradication, enhanced biosecurity and controlled marketing plan, vaccination programmes of commercial layer chickens with novel RP vaccines may represent an important tool for preventing HPAI-related mortalities and decreasing viral load during a catastrophic influenza outbreak. RESEARCH HIGHLIGHTS Immunization of poultry following a vaccination schedule consisting of inactivated and RNA particle vaccines offered significant protection against lethal disease following HPAIV challenge. Virus shedding was significantly (P < 0.05) reduced in chickens vaccinated with either inactivated and/or recombinant vaccines. Serum antibody titres were not a reliable indicator of protection. An inactivated vaccine containing 384 HAU of the homologous antigen was unable to induce complete protection.


Assuntos
Galinhas , Vírus da Influenza A/imunologia , Vacinas contra Influenza , Influenza Aviária/prevenção & controle , Animais , Anticorpos Antivirais/sangue , Feminino , Testes de Inibição da Hemaglutinação/veterinária , Imunização Secundária/veterinária , Influenza Aviária/mortalidade , Masculino , Vacinas de Produtos Inativados , Eliminação de Partículas Virais
13.
Theor Popul Biol ; 126: 59-71, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30825417

RESUMO

Highly pathogenic avian influenza (HPAI) outbreaks are devastating to poultry industries and pose a risk to human health. There is concern that demand for free-range poultry products could increase the number of HPAI outbreaks by increasing the potential for low pathogenic avian influenza (LPAI) introduction to commercial flocks. We formulate stochastic mathematical models to understand how poultry-housing (barn, free-range and caged) within the meat and layer sectors interacts with a continuous low-level risk of introduction from wild birds, heterogeneity in virus transmission rates and virus mutation probabilities, to affect the risk of HPAI emergence - at both the shed and industry scales. For H5 and H7 viruses, restricted mixing in caged systems, free-range outdoor access and, particularly, production cycle length significantly influence HPAI risk between sectors of the chicken production industry. Results demonstrate how delay between virus mutation and detection, ensuing from the short production cycle, large shed sizes and industry reporting requirements, could mean that HPAI emerges in meat-production sheds but is undetected with few birds affected. We also find that the Australian HPAI outbreak history appears to be better explained by low LPAI introduction rates and low mutation probabilities, rather than extremely rare introduction and relatively high mutation probabilities.


Assuntos
Criação de Animais Domésticos/métodos , Vírus da Influenza A/patogenicidade , Influenza Aviária/epidemiologia , Animais , Austrália/epidemiologia , Simulação por Computador , Surtos de Doenças , Abrigo para Animais , Vírus da Influenza A/genética , Influenza Aviária/prevenção & controle , Modelos Biológicos , Mutação , Aves Domésticas , Fatores de Risco , Processos Estocásticos
14.
Transbound Emerg Dis ; 66(4): 1758-1761, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30903740

RESUMO

H7N9 subtype avian influenza viruses (AIV) circulating in China over recent years have had an enormous impact on public health and economy. During the period between November 2016 and April 2017, an increase in human infections caused by these viruses was reported, with rapid emergence and spread of variants in China. Consequently, the government of China implemented a controversial vaccination strategy in September 2017. Here, we provide evidence of the prevalence of H7N9 AIVs in China based on systematic large-scale surveillance in poultry during 2013-2018. Emerging variants were confirmed as highly pathogenic in chickens using the intravenous pathogenicity index (IVPI) test. The currently available vaccine provided complete protection against the H7N9 HPAIV challenge in chickens. The collective findings clearly indicate that the vaccination strategy implemented not only significantly decreases the prevalence of H7N9 AIVs in poultry but also effectively prevents human infection with H7N9 viruses.


Assuntos
Monitoramento Epidemiológico/veterinária , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Vacinação/veterinária , Animais , Galinhas , China/epidemiologia , Columbidae , Patos , Gansos , Subtipo H7N9 do Vírus da Influenza A/imunologia , Influenza Aviária/prevenção & controle , Influenza Aviária/virologia , Doenças das Aves Domésticas/prevenção & controle , Doenças das Aves Domésticas/virologia , Prevalência , Virulência
15.
Prev Vet Med ; 165: 8-14, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30851932

RESUMO

As of 2018, Australia has experienced seven outbreaks of highly pathogenic avian influenza (HPAI) in poultry since 1976, all of which involved chickens. There is concern that increases in free-range farming could heighten HPAI outbreak risk due to the potential for greater contact between chickens and wild birds that are known to carry low pathogenic avian influenza (LPAI). We use mathematical models to assess the effect of a shift to free-range farming on the risk of HPAI outbreaks of H5 or H7 in the Australian commercial chicken industry, and the potential for intervention strategies to reduce this risk. We find that a shift of 25% of conventional indoor farms to free-range farming practices would result in a 6-7% increase in the risk of a HPAI outbreak. Current practices to treat water are highly effective, reducing the risk of outbreaks by 25-28% compared to no water treatment. Halving wild bird presence in feed storage areas could reduce risk by 16-19% while halving wild bird access of potential bridge-species to sheds could reduce outbreak risk by 23-25%, and relatively small improvements in biosecurity measures could entirely compensate for increased risks due to the increasing proportion of free-range farms in the industry. The short production cycle and cleaning practices for chicken meat sheds considerably reduce the risk that an introduced low pathogenic avian influenza virus is maintained in the flock until it is detected as HPAI through increased mortality of chickens. These findings help explain HPAI outbreak history in Australia and suggest practical changes in biosecurity practices that could reduce the risk of future outbreaks.


Assuntos
Criação de Animais Domésticos/métodos , Surtos de Doenças/veterinária , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Animais , Austrália/epidemiologia , Galinhas/virologia , Surtos de Doenças/prevenção & controle , Abrigo para Animais , Influenza Aviária/epidemiologia , Modelos Teóricos , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/virologia
16.
Vet Immunol Immunopathol ; 209: 78-83, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30885310

RESUMO

This study aimed to investigate whether intranasally coadministered four tandem copies of extracellular domains of M2 (M2e) and polyethyleneimine (PEI), a mucosal adjuvant, can protect chickens against H9N2 influenza A virus infection. Groups of chickens were intranasally vaccinated with M2e plus PEI adjuvant, M2e alone or PEI adjuvant, and antibody (serum IgG and mucosal IgA) and cellular (CD4+ T cells and IFN-γ levels) immune responses were measured post-vaccination. We demonstrated that the chickens vaccinated with M2e plus PEI adjuvant showed significantly (p < 0.05) higher M2e-specific systemic IgG and mucosal IgA responses compared to the chickens that received either M2e alone or PEI adjuvant. The IgA responses measured in lungs were almost comparable to that of the serum IgG levels. Upon restimulation of the vaccinated peripheral blood mononuclear cells (PBMCs) with M2e antigen, significantly (p < 0.05) higher IFN-γ levels were observed only in M2e plus PEI adjuvant vaccinated group. Lymphoproliferative and CD4+ T cell responses, as measured by MTT-based assay and flow cytometry, respectively, were also observed significantly (p < 0.05) higher in M2e plus PEI adjuvant vaccinated chickens. On challenge with the H9N2 virus (104TCID50) at 28th day post-vaccination, M2e plus PEI adjuvant vaccinated group exhibited lower lung inflammation and viral load compared to the chickens treated with either M2e alone or PEI adjuvant. In summary, we show that intranasally coadministered M2e and PEI adjuvant can elicit humoral and cell-mediated immune responses and can reduce viremia levels in chickens post H9N2 infection in chickens.


Assuntos
Galinhas , Vírus da Influenza A Subtipo H9N2 , Vacinas contra Influenza/imunologia , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Proteínas da Matriz Viral/imunologia , Administração Intranasal , Animais , Feminino , Imunidade Celular , Imunidade Humoral , Imunidade nas Mucosas , Imunogenicidade da Vacina , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/patologia , Influenza Aviária/virologia , Pulmão/patologia , Pneumopatias/patologia , Pneumopatias/veterinária , Polietilenoimina , Doenças das Aves Domésticas/patologia , Doenças das Aves Domésticas/virologia , Domínios Proteicos , Distribuição Aleatória , Eliminação de Partículas Virais
17.
Viruses ; 11(3)2019 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-30917500

RESUMO

Highly pathogenic avian influenza (HPAI) and Newcastle disease are economically important avian diseases worldwide. Effective vaccination is critical to control these diseases in poultry. Live attenuated Newcastle disease virus (NDV) vectored vaccines have been developed for bivalent vaccination against HPAI viruses and NDV. These vaccines have been generated by inserting the hemagglutinin (HA) gene of avian influenza virus into NDV genomes. In laboratory settings, several experimental NDV-vectored vaccines have protected specific pathogen-free chickens from mortality, clinical signs, and virus shedding against H5 and H7 HPAI viruses and NDV challenges. NDV-vectored H5 vaccines have been licensed for poultry vaccination in China and Mexico. Recently, an antigenically chimeric NDV vector has been generated to overcome pre-existing immunity to NDV in poultry and to provide early protection of poultry in the field. Prime immunization of one-day-old poults with a chimeric NDV vector followed by boosting with a conventional NDV vector has shown to protect broiler chickens against H5 HPAI viruses and a highly virulent NDV. This novel vaccination approach can provide efficient control of HPAI viruses in the field and facilitate poultry vaccination.


Assuntos
Vetores Genéticos , Virus da Influenza A Subtipo H5N1/genética , Vacinas contra Influenza/genética , Influenza Aviária/prevenção & controle , Vírus da Doença de Newcastle/genética , Animais , Anticorpos Antivirais/imunologia , Antígenos Virais/genética , Antígenos Virais/imunologia , Galinhas , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Virus da Influenza A Subtipo H5N1/patogenicidade , Vacinas contra Influenza/imunologia , Influenza Aviária/virologia , Influenza Humana/virologia , Vacinas Atenuadas/genética , Vacinas Atenuadas/imunologia , Eliminação de Partículas Virais
18.
Vet Immunol Immunopathol ; 208: 44-52, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30712791

RESUMO

Melanoma Differentiation-Associated protein 5 (MDA5) is a cytoplasmic sensor for viral invasion and plays an important role in regulation of the immune response against Newcastle disease virus (NDV) in chickens. MDA5 was used as an adjuvant to enhance the humoral immune response against influenza virus. In the current study, truncated chicken MDA5 [1-483 aa, chMDA5(483aa)] expressed by recombinant adenovirus was administered to specific-pathogen-free (SPF) chickens to improve the immune response induced by inactivated NDV vaccine. A total of 156 SPF chickens were divided into six groups, and after two rounds of immunization, the humoral immune response, cell-mediated immune (CMI) response and the protective efficacy of the vaccines against NDV challenge were evaluated. The results showed that co-administration of chMDA5(483aa) expressed by adenovirus increased the NDV-specific antibody response by 1.7 times and chickens received chMDA5(483aa) also gained a higher level of CMI response. Consistently, the protective efficacy of the inactivated NDV vaccine against virulent NDV (vNDV) challenge was improved by co-administrate with chMDA5(483aa), as indicated by the reduced morbidity and pathological lesions, lower levels of viral load in organs and reduced virus shedding. Our study demonstrated that chMDA5(433aa) expressed by adenovirus could enhance the immune efficacy of inactivated NDV vaccine in chickens and could be a potential adjuvant candidate in developing chicken NDV vaccines.


Assuntos
Anticorpos Antivirais/sangue , Helicase IFIH1 Induzida por Interferon/imunologia , Doença de Newcastle/prevenção & controle , Vacinas Virais/imunologia , Adenoviridae/genética , Adjuvantes Imunológicos/administração & dosagem , Animais , Galinhas , Imunidade Celular , Imunidade Humoral , Influenza Aviária/prevenção & controle , Helicase IFIH1 Induzida por Interferon/genética , Doença de Newcastle/imunologia , Vírus da Doença de Newcastle , Organismos Livres de Patógenos Específicos , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologia , Carga Viral , Vacinas Virais/administração & dosagem , Eliminação de Partículas Virais
19.
Biochem Soc Trans ; 47(1): 251-264, 2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30647144

RESUMO

Influenza-related pathologies affect millions of people each year and the impact of influenza on the global economy and in our everyday lives has been well documented. Influenza viruses not only infect humans but also are zoonotic pathogens that infect various avian and mammalian species, which serve as viral reservoirs. While there are several strains of influenza currently circulating in animal species, H2 influenza viruses have a unique history and are of particular concern. The 1957 'Asian Flu' pandemic was caused by H2N2 influenza viruses and circulated among humans from 1957 to 1968 before it was replaced by viruses of the H3N2 subtype. This review focuses on avian influenza viruses of the H2 subtype and the role these viruses play in human infections. H2 influenza viral infections in humans would present a unique challenge to medical and scientific researchers. Much of the world's population lacks any pre-existing immunity to the H2N2 viruses that circulated 50-60 years ago. If viruses of this subtype began circulating in the human population again, the majority of people alive today would have no immunity to H2 influenza viruses. Since H2N2 influenza viruses have effectively circulated in people in the past, there is a need for additional research to characterize currently circulating H2 influenza viruses. There is also a need to stockpile vaccines that are effective against both historical H2 laboratory isolates and H2 viruses currently circulating in birds to protect against a future pandemic.


Assuntos
Vírus da Influenza A Subtipo H2N2/imunologia , Vacinas contra Influenza/biossíntese , Influenza Aviária/epidemiologia , Influenza Aviária/prevenção & controle , Pandemias/prevenção & controle , Animais , Sítios de Ligação , Aves , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Humanos , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Influenza Humana/transmissão , Ácido N-Acetilneuramínico/metabolismo , Suínos
20.
Virology ; 529: 7-15, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30641481

RESUMO

H9N2 avian influenza viruses (AIVs) were prevailing in chickens, causing great economic losses and public health threats. In this study, turkey herpesviruses (HVT) was cloned as an infectious bacterial artificial chromosomes (BAC). Recombinant HVT (rHVT-H9) containing hemagglutinin (HA) gene from H9N2 virus were constructed via galactokinase (galK) selection and clustered regularly interspaced short palindromic repeats/associated 9 (CRISPR/Cas9) gene editing system. The recombinant rHVT-H9 showed no difference with parent HVT in plague morphology and virus replication kinetics. H9 protein expression of rHVT-H9 could be detected by western blot and indirect immunofluorescence assay (IFA) in vitro and in vivo. Immunization with rHVT-H9 could induce robust humoral and cellular immunity in chickens. In the challenge study, no chicken shed H9N2 virus from oropharynx and cloaca, and no H9N2 virus was found in viscera in vaccination groups. The result suggests that rHVT-H9 provides effective protection against H9N2 AIV in chickens.


Assuntos
Galinhas , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Herpesvirus Meleagrídeo 1/metabolismo , Vírus da Influenza A Subtipo H9N2 , Influenza Aviária/prevenção & controle , Animais , Linhagem Celular , Regulação Viral da Expressão Gênica , Engenharia Genética , Vacinas contra Influenza , Interferon gama , Ensaio de Placa Viral
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