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1.
Vet Microbiol ; 235: 234-242, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31383307

RESUMO

During 2012-2015, six H5N1 avian influenza viruses were isolated from domestic birds and the environment around Qinghai Lake. Phylogenetic analysis of HA genes revealed that A/chicken/Gansu/XG2/2012 (CK/GS/XG2/12) belonged to clade 2.3.2.1a, while A/environment/Qinghai/1/2013 (EN/QH/1/13), A/chicken/Qinghai/QH1/2015 (CK/QH/QH1/15), A/chicken/Qinghai/QH2/2015 (CK/QH/QH2/15), A/chicken/Qinghai/QH3/2015 (CK/QH/QH3/15), and A/goose/Qinghai/QH6/2015 (GS/QH/QH6/15) belonged to clade 2.3.2.1c. Further analysis of the internal genes of the isolates found that the PB2 gene of EN/QH/1/13 had 99.6% nucleotide identity with that of A/tiger/Jiangsu/1/2013 (H5N1), which clustered into an independent branch with PB2 from multiple subtypes. PB2, PB1, and M genes of CK/QH/QH3/15 were from H9N2, suggesting it was a reassortant of H5N1 and H9N2. Animal studies of three selected viruses revealed that CK/GS/XG2/12, EN/QH/1/13, and CK/QH/QH3/15 were highly lethal to chickens, with intravenous pathogenicity indexes (IVPIs) of 2.97, 2.81, and 3.00, respectively, and systemically replicated in chickens. In a mouse study, three selected H5N1 viruses were highly pathogenic to mice and readily replicated in the lungs, nasal turbinates, kidneys, spleens, and brains. Therefore, isolates in this study appear to be novel reassortants that were circulating at the interface of wild and domestic birds around Qinghai Lake and are lethal to chickens and mice. These data suggest that more extensive surveillance should be implemented, and matched vaccines should be chosen for the domestic birds in this area.


Assuntos
Animais Domésticos/virologia , Virus da Influenza A Subtipo H5N1/genética , Influenza Aviária/epidemiologia , Lagos/virologia , Células A549 , Animais , Galinhas/virologia , China/epidemiologia , Cães , Patos/virologia , Evolução Molecular , Feminino , Humanos , Virus da Influenza A Subtipo H5N1/patogenicidade , Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/patogenicidade , Influenza Aviária/mortalidade , Influenza Aviária/virologia , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos BALB C , Filogenia , Vírus Reordenados/genética , Vírus Reordenados/patogenicidade , Replicação Viral
2.
Artigo em Inglês | MEDLINE | ID: mdl-31174705

RESUMO

This study was conducted to perform the comparative molecular characterization of avian influenza virus (AIV) H9N2, pathogenicity and seroprevalence in commercial and backyard poultry flocks. Fifty commercial poultry flocks were investigated between 2012 and 2015. Eighteen flocks (36%) out of 50 were positive HA. Seven (38.9%) out of 18 were positive by chromatographic strip test for AI common antigen. By Real-time RT-PCR, only two flocks were positive H9. The molecular characterization of two different AI-H9N2 viruses, one isolated from a broiler flock (A/chicken/Egypt/Mansoura-18/2013) and the other from a layer flock (A/chicken/Egypt/Mansoura-36/2015) was conducted on HA gene. Moreover, a higher seroprevalence, using the broiler strain as a known antigen, was shown in backyard chicken flocks 15/26 (57.7%) than duck flocks 9/74 (12.2%). Interestingly, the pathogenicity index (PI) of the H9N2 broiler strain in inoculated experimental chickens ranged from 1.2 (oculonasal route) to 1.9 (Intravenous route). The PI indicated a highly pathogenic effect, with high mortality (up to 100%) in the inoculated chickens correlated with the high mortality (80%) in the flock where the virus was isolated. The firstly recorded clinical signs, including cyanosis in the combs and wattles and subcutaneous haemorrhages in the leg shanks and lesions, as well as histopathology and immunohistochemistry, revealed a systemic infection of the high pathogenicity with the H9N2 virus. Conversely, the H9N2 layer strain showed a low pathogenicity. In conclusion, as a first report, the molecular analysis and pathogenicity of the tested strains confirmed the presence of a high pathogenicity AIV-H9N2 with systemic infections.


Assuntos
Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/patogenicidade , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Aves Domésticas/virologia , Animais , Galinhas/virologia , Cianose/virologia , Patos/virologia , Egito/epidemiologia , Influenza Aviária/mortalidade , Doenças das Aves Domésticas/mortalidade , Reação em Cadeia da Polimerase em Tempo Real , Estudos Soroepidemiológicos , Perus/virologia , Virulência
3.
BMC Vet Res ; 15(1): 142, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-31077209

RESUMO

BACKGROUND: There is paucity of data on the virulence of highly pathogenic (HP) avian influenza viruses (AIV) H7 in ducks compared to HPAIV H5. Here, the virulence of HPAIV H7N1 (designated H7N1-FPV34 and H7N1-It99) and H7N7 (designated H7N7-FPV27) was assessed in Pekin and/or Muscovy ducklings after intrachoanal (IC) or intramuscular (IM) infection. RESULTS: The morbidity rate ranged from 60 to 100% and mortality rate from 20 to 80% depending on the duck species, virus strain and/or challenge route. All Muscovy ducklings inoculated IC with H7N7-FPV27 or H7N1-FPV34 exhibited mild to severe clinical signs resulting in the death of 2/10 and 8/10 ducklings, respectively. Also, 2/10 and 6/9 of inoculated Muscovy ducklings died after IC or IM infection with H7N1-It99, respectively. Moreover, 5/10 Pekin ducklings inoculated IC or IM with H7N1-It99 died. The level of virus detected in the oropharyngeal swabs was higher than in the cloacal swabs. CONCLUSION: Taken together, HPAIV H7 cause mortality and morbidity in Muscovy and Pekin ducklings. The severity of disease in Muscovy ducklings depended on the virus strain and/or route of infection. Preferential replication of the virus in the respiratory tract compared to the gut merits further investigation.


Assuntos
Patos , Vírus da Influenza A Subtipo H7N1/patogenicidade , Vírus da Influenza A Subtipo H7N7/patogenicidade , Influenza Aviária/virologia , Animais , Influenza Aviária/mortalidade , Influenza Aviária/patologia , Virulência
4.
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
5.
Vet Microbiol ; 231: 183-190, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30955808

RESUMO

Highly pathogenic avian influenza (HPAI) is a viral disease with devastating consequences to the poultry industry as it results in high morbidity, mortality and international trade restrictions. In the present study, we characterized age-related differences in terms of pathology in commercial white broad breasted turkeys inoculated with A/turkey/Minnesota/12582/2015 (H5N2) HPAIV clade 2.3.4.4A, a virus from the largest HPAI poultry outbreak that affected the Unites States in 2014-2015. Turkeys infected at 6-weeks of age showed inapparent to little clinical signs with rapid disease progression, reaching 100% mortality at 3 days post infection (dpi). In contrast, turkeys infected at 16-weeks of age developed ataxia and lethargy and reached 100% mortality by 5 dpi. Infection in the 6-weeks old turkeys resulted in peracute lesions consistent of extensive hemorrhages, edema and necrosis, but inflammation was not prominent. In the 16-weeks old turkeys, necrosis and hemorrhages in tissues were accompanied by a more prominent subacute inflammatory infiltrate. Both age groups showed presence of avian influenza virus (AIV) nucleoprotein (NP) in multiple cell types including neurons, glial cells, ependymal cells, respiratory epithelial cells, air capillary epithelium and pulmonary macrophages, cardiac myocytes, smooth muscle fibers, pancreatic acini and ductal cells. Cells of the vascular walls stained strongly positive for viral antigens, but no positivity was found in the endothelial cells of any organs. These findings indicate that age is a determinant factor in the progression of the disease and delay of mortality during infection with the H5N2 clade 2.3.4.4A HPAI virus in naïve white broad breasted turkeys.


Assuntos
Vírus da Influenza A Subtipo H5N2/patogenicidade , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Perus/virologia , Fatores Etários , Animais , Surtos de Doenças , Imuno-Histoquímica , Influenza Aviária/mortalidade , Influenza Aviária/patologia , Doenças das Aves Domésticas/mortalidade , Doenças das Aves Domésticas/patologia , Eliminação de Partículas Virais
6.
Virology ; 530: 11-18, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30753976

RESUMO

H5Nx clade 2.3.4.4 highly pathogenic avian influenza viruses (HPAIVs) have been disseminated to wide geographic regions since 2014. In 2016, five distinct genotypes (C-1 to C-5) of clade 2.3.4.4c H5N6 HPAIVs were detected in South Korea. In this study, we evaluated the pathogenicity, susceptibility to infection, and transmissibility of the two strains representing the C-1 and C-4 genotypes of the H5N6 viruses, which have different PA and NS gene, in domestic ducks. Although the susceptibility to infection of domestic ducks to the two strains was similar, the C-4 genotype virus induced higher mortality in ducks than C-1 genotype virus. A higher titer of viral shedding were detected in ducks challenged with the C-4 genotype virus compared with the C-1 genotype virus. These results indicated that the reassortment of HPAIVs with prevailing low pathogenic avian influenza viruses could effect on the pathogenicity in ducks.


Assuntos
Patos/virologia , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , RNA Replicase/genética , Proteínas não Estruturais Virais/genética , Proteínas Virais/genética , Animais , Variação Genética , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Influenza Aviária/mortalidade , Influenza Aviária/transmissão , Coreia (Geográfico) , Análise de Sobrevida , Eliminação de Partículas Virais
7.
J Wildl Dis ; 55(1): 164-168, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30124391

RESUMO

An outbreak of highly pathogenic avian influenza (HPAI) led to heavy losses of poultry in commercial farms in North America in 2014-15. Enhanced surveillance by virologists and pathologists at the US Geological Survey National Wildlife Health Center and its partners resulted in the identification of lethal infections with clade 2.3.4.4 subgroup icA2 H5N8 and novel reassortant H5N2 viruses in diverse wild raptor species that died concomitant with the poultry epizootic in the US. A range of pathologic abnormalities were present in dead raptors, including necrotizing encephalitis and myocarditis, pancreatic necrosis, and pulmonary congestion and edema. Raptors are highly susceptible to disease caused by infection with HPAI clade 2.3.4.4 viruses.


Assuntos
Vírus da Influenza A Subtipo H5N2 , Vírus da Influenza A Subtipo H5N8 , Influenza Aviária/virologia , Aves Predatórias/virologia , Animais , Animais Selvagens , Influenza Aviária/epidemiologia , Influenza Aviária/mortalidade , Estados Unidos/epidemiologia
8.
Mol Genet Genomics ; 294(1): 121-133, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30238319

RESUMO

Gene duplication and amino acid substitution are two types of genetic innovations of antiviral genes in inhibiting the emerging pathogens in different species. Mx proteins are well known for inhibiting negative-stranded RNA viruses and have evolved a number of paralogs or orthologs, showing distinct antiviral activities or capacities within or between species. The presence of upstream genes in the signaling pathway(s) that activates Mx genes (upstream regulators of Mx gene) also exhibits variety across species. The association between the evolution of Mx gene and their upstream regulators and the various antiviral capacities in host species has not been investigated. Herein, we traced the evolution of Mx gene and profiled the gene birth/death events on each branch of the 64 chordate species. We provided additional support that the diversity in gene member and amino acid changes in the different clades is correlated to their various antiviral activities of the species. We identified amino acid substitutions that may lead to the functional divergence between Mx paralogs in rodents. Although the copy number of the Mx gene is conserved in birds, infection by influenza A virus (IAV) results in diverse morbidity rates in different avian species. The evidences of gene interaction in the IAV-induced pathway and the genome analysis performed in this study indicated that the existence of the upstream regulators of Mx gene exhibits variation among different species, particularly in birds. The variation is related to the differences in the expression of Mx genes, resulting in the antiviral specificity and morbidity rates in avian species. We conclude that the antiviral capacity in host species is associated with the variations in the gene number of the Mx gene family and the existence of upstream regulators of Mx gene as well.


Assuntos
Aves/virologia , Dosagem de Genes , Vírus da Influenza A/patogenicidade , Influenza Aviária/mortalidade , Proteínas de Resistência a Myxovirus/genética , Substituição de Aminoácidos , Animais , Proteínas Aviárias/genética , Aves/genética , Evolução Molecular , Duplicação Gênica , Regulação da Expressão Gênica , Variação Genética , Influenza Aviária/genética , Transdução de Sinais
9.
Avian Pathol ; 48(2): 98-110, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30484684

RESUMO

An outbreak of low pathogenic avian influenza (LPAI) subtype H6N1 (intravenous pathogenicity index = 0.11) infection occurred in four productive brown layer flocks on three farms in the Netherlands within a period of two months. The farms were located at a maximum distance of 4.6 km from each other. The infections were associated with egg production drops up to 74%, pale eggshells and persisting high mortality up to 3.2% per week. Three flocks were slaughtered prematurely as they were not profitable anymore. Newcastle disease, infectious bronchitis, egg drop syndrome and Mycoplasma gallisepticum infections could very likely be excluded as cause of or contributor to the condition in the field. Also, the anticoccidial drug nicarbazin, which can cause egg production drops and eggshell decolouration, was not detected in eggs from affected flocks. Furthermore, post mortem examinations revealed no lesions indicative of bacterial infection. Moreover, bacteriological analysis of hens was negative. The condition was reproduced in commercial brown layers after intratracheal inoculation with virus isolates from affected flocks. It is concluded that the LPAI H6N1 virus is very likely the only cause of the disease. An overview of main manuscripts published since 1976 describing non-H5 and non-H7 avian influenza (AI) virus infections in chickens and their biological significance is included in the present study, in which once more is shown that not only high pathogenic AI virus subtypes H5 and H7 can be detrimental to flocks of productive layers, but also non-H5 and non-H7 LPAI viruses (H6N1 virus). RESEARCH HIGHLIGHTS LPAI H6N1 can be detrimental to productive layers Detrimental effects are severe egg drop and persistent high mortality LPAI H6N1 virus outbreak seems to be self-limiting.


Assuntos
Galinhas/virologia , Surtos de Doenças/veterinária , Vírus da Influenza A/patogenicidade , Influenza Aviária/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Animais , Casca de Ovo/patologia , Ovos , Feminino , Influenza Aviária/mortalidade , Influenza Aviária/patologia , Influenza Aviária/virologia , Países Baixos/epidemiologia , Doenças das Aves Domésticas/mortalidade , Doenças das Aves Domésticas/patologia , Doenças das Aves Domésticas/virologia
10.
Emerg Microbes Infect ; 7(1): 204, 2018 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-30514922

RESUMO

Highly pathogenic avian influenza virus (HPAIV) infection in poultry caused devastating mortality and economic losses. HPAIV of subtypes H5 and H7 emerge from precursor viruses of low pathogenicity (LP) by spontaneous mutation associated with a shift in the susceptibility of the endoproteolytic cleavage site of the viral hemagglutinin protein from trypsin- to furin-like proteases. A recently described natural pair of LP/HP H7N7 viruses derived from two spatio-temporally linked outbreaks in layer chickens was used to study how a minority of mutated HP virions after de novo generation in a single host might gain primacy. Co-infection experiments in embryonated eggs and in chickens were conducted to investigate amplification, spread and transmissionof HPAIV within a poultry population that experiences concurrent infection by an antigenically identical LP precursor virus. Simultaneous LPAIV co-infection (inoculum dose of 106 egg-infectious dose 50% endpoint (EID50)/0.5 mL) withincreasing titers of HPAIV from 101 to 105.7 EID50/0.5 mL) had a significant impeding impact on HP H7 replication, viral excretion kinetics, clinical signs and histopathological lesions (in vivo) and on embryo mortality (in ovo). LP/HP co-infected chickens required a hundredfold higher virus dose (HPAIV inoculum of 105 EID50) compared to HPAIV mono-infection (HPAIV inoculum of 103 EID50) to develop overt clinical signs, mortality and virus spread to uninfected sentinels. Escape and spread of HP phenotypes after de novo generation in an index host may therefore be highly precarious due to significant competition with co-circulating LP precursor virus.


Assuntos
Galinhas/virologia , Coinfecção/veterinária , Vírus da Influenza A Subtipo H7N7/genética , Vírus da Influenza A Subtipo H7N7/patogenicidade , Influenza Aviária/transmissão , Óvulo/virologia , Animais , Embrião de Galinha/virologia , Coinfecção/virologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Influenza Aviária/mortalidade , Mutação , Virulência
11.
Vet Microbiol ; 227: 127-132, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30473343

RESUMO

Reported mass mortalities in wild pigeons and doves during the 2017/2018 Clade 2.3.4.4 HPAI H5N8 outbreaks in South Africa necessitated an investigation of healthy racing pigeons for their susceptibility and ability to transmit a Clade 2.3.4.4 sub-group B virus of South African origin. Pigeons challenged with medium (104.5 EID50) and high doses (106 EID50) but not a low dose (103 EID50) of virus, shed virus in low levels of <103 EID50/ml from the oropharynx and cloaca for up to eight days, with peak shedding around 4 days post challenge. Challenged pigeons were able to transmit the virus to contact pigeons, but not contact chickens. Neither pigeons nor chickens presented clinical disease, and only two pigeons in the group that received the high challenge dose developed influenza A-virus specific antibodies. The levels of virus shed by the racing pigeons were well below the published bird infectious dose 50 values for most poultry, especially chickens, therefore the risk that racing pigeons could act as propagators and disseminators through excretion of Clade 2.3.4.4 HPAI H5N8 strains remains negligible.


Assuntos
Doenças das Aves/virologia , Columbidae/virologia , Surtos de Doenças/veterinária , Vírus da Influenza A Subtipo H5N8/patogenicidade , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Animais , Anticorpos Antivirais , Doenças das Aves/mortalidade , Doenças das Aves/transmissão , Galinhas , Surtos de Doenças/estatística & dados numéricos , Vírus da Influenza A Subtipo H5N8/classificação , Vírus da Influenza A Subtipo H5N8/genética , Vírus da Influenza A Subtipo H5N8/isolamento & purificação , Influenza Aviária/mortalidade , Influenza Aviária/transmissão , Doenças das Aves Domésticas/mortalidade , Doenças das Aves Domésticas/patologia , África do Sul , Eliminação de Partículas Virais
12.
BMC Vet Res ; 14(1): 358, 2018 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-30458777

RESUMO

BACKGROUND: H9N2 avian influenza virus is endemic in Egyptian poultry flocks. The role of the live viral vaccines such as LaSota in exaggeration of the clinical picture of H9N2 infection under field conditions is significantly important leading to severe economic losses due to higher mortality and lower growth performance. This experiment was designed to identify the possible interaction between experimental infection with H9N2 virus and NDV live vaccine (LaSota strain) in broiler chickens. Six groups each of 20 broiler chicks were used. Three groups (G1-3) were infected with H9N2 and vaccinated with LaSota, 3 days before, at the same day or 3 days post vaccination (dpv), while the remaining groups (G4-6) were non-vaccinated infected, vaccinated non-infected and non-vaccinated non-infected. RESULTS: The highest mortality rate (37.5%) was noticed in chickens of G1 (H9N2 infected 3 days prior LaSota vaccination). Also, this bird group had the most severe clinical signs, histopathological lesions and the longest viral shedding for 9 days post infection (dpi). In the 2nd and 3rd groups, the mortality rate was the similar (31.2%) with less pronounced clinical signs, histopathological lesions and H9N2 shedding was for only 6 dpi with the least shedding quantity in chickens of G3. The control non-vaccinated infected chickens (G4) had 18.7% mortality with the least degree of clinical signs, lesions and the highest viral shedding quantity but only for 6 dpi. At 35 days of age, there was a statistical significant decrease (P < 0.05) in chicken's body weight of all H9N2 infected groups from G1 to G4 compared to non-infected control groups, G5 and G6 respectively. CONCLUSION: It was clear that laSota vaccination significantly affect H9N2 infection in broiler chickens regarding clinical signs, mortality rate, lesions, performance and viral shedding.


Assuntos
Vírus da Influenza A Subtipo H9N2 , Influenza Aviária/imunologia , Vírus da Doença de Newcastle/imunologia , Vacinas Virais/imunologia , Animais , Galinhas/imunologia , Galinhas/virologia , Vírus da Influenza A Subtipo H9N2/imunologia , Influenza Aviária/mortalidade , Influenza Aviária/prevenção & controle , Influenza Aviária/virologia , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Vacinas Virais/farmacologia , Eliminação de Partículas Virais
13.
Cell Host Microbe ; 24(4): 558-568.e7, 2018 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-30269969

RESUMO

H7N9 low pathogenic influenza viruses emerged in China in 2013 and mutated to highly pathogenic strains in 2017, resulting in human infections and disease in chickens. To control spread, a bivalent H5/H7 inactivated vaccine was introduced in poultry in September 2017. To monitor virus evolution and vaccine efficacy, we collected 53,884 poultry samples across China from February 2017 to January 2018. We isolated 252 H7N9 low pathogenic viruses, 69 H7N9 highly pathogenic viruses, and one H7N2 highly pathogenic virus, of which two low pathogenic and 14 highly pathogenic strains were collected after vaccine introduction. Genetic analysis of highly pathogenic strains revealed nine genotypes, one of which is predominant and widespread and contains strains exhibiting high virulence in mice. Additionally, some H7N9 and H7N2 viruses carrying duck virus genes are lethal in ducks. Thus, although vaccination reduced H7N9 infections, the increased virulence and expanded host range to ducks pose new challenges.


Assuntos
Doenças Transmissíveis Emergentes/virologia , Evolução Molecular , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Animais , Galinhas , China , Doenças Transmissíveis Emergentes/sangue , Doenças Transmissíveis Emergentes/imunologia , Doenças Transmissíveis Emergentes/mortalidade , Patos , Feminino , Humanos , Subtipo H7N9 do Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Influenza Aviária/sangue , Influenza Aviária/imunologia , Influenza Aviária/mortalidade , Influenza Humana/sangue , Influenza Humana/imunologia , Influenza Humana/mortalidade , Camundongos , Camundongos Endogâmicos BALB C , Organismos Livres de Patógenos Específicos , Vacinas de Produtos Inativados/imunologia , Virulência/genética
14.
Viruses ; 10(9)2018 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-30205456

RESUMO

In contrast to previous incursions of highly pathogenic avian influenza (HPAIV) H5 viruses, H5N8 clade 2.3.4.4b viruses caused numerous cases of lethal infections in white-tailed sea eagles (Haliaeetus albicilla) affecting mainly young eagles (younger than five years of age) in Germany during winter 2016/2017. Until April 2017, 17 HPAIV H5N8-positive white-tailed sea eagles had been detected (three found alive and 14 carcasses) by real-time RT-PCR and partial nucleotide sequence analyses. Severe neurological clinical signs were noticed which were corroborated by immunohistopathology revealing mild to moderate, oligo- to multifocal necrotizing virus-induced polioencephalitis. Lethal lead (Pb) concentrations, a main factor of mortality in sea eagles in previous years, could be ruled out by atomic absorption spectrometry. HPAIV H5 clade 2.3.4.4b reportedly is the first highly pathogenic influenza virus known to induce fatal disease in European white-tailed see eagles. This virus strain may become a new health threat to a highly protected species across its distribution range in Eurasia. Positive cloacal swabs suggest that eagles can spread the virus with their faeces.


Assuntos
Águias/virologia , Vírus da Influenza A Subtipo H5N8/isolamento & purificação , Vírus da Influenza A Subtipo H5N8/patogenicidade , Influenza Aviária/mortalidade , Influenza Aviária/virologia , Animais , Encefalite/etiologia , Encefalite/patologia , Alemanha/epidemiologia , Imuno-Histoquímica , Influenza Aviária/epidemiologia , Influenza Aviária/patologia , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de DNA
15.
Infect Genet Evol ; 64: 13-31, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29883773

RESUMO

H5 and H7 subtypes of low pathogenicity avian influenza viruses (LPAIVs) have the potential to evolve into highly pathogenic avian influenza viruses (HPAIVs), causing high mortality in galliforme poultry with substantial economic losses for the poultry industry. This study provides direct evidence of H7N7 LPAIV mutation to HPAIV on a single poultry premises during an outbreak that occurred in June 2008 in free range laying hens in Oxfordshire, UK. We report the first detection of a rare di-basic cleavage site (CS) motif (PEIPKKRGLF), unique to galliformes, that has previously been associated with a LPAIV phenotype. Three distinct HPAIV CS sequences (PEIPKRKKRGLF, PEIPKKKKRGLF and PEIPKKKKKKRGLF) were identified in the infected sheds suggesting molecular evolution at the outbreak premises. Further evidence for H7N7 LPAIV preceding mutation to HPAIV was derived by examining clinical signs, epidemiological descriptions and analysing laboratory results on the timing and proportions of seroconversion and virus shedding at each infected shed on the premises. In addition to describing how the outbreak was diagnosed and managed via statutory laboratory testing, phylogenetic analysis revealed reassortant events during 2006-2008 that suggested likely incursion of a wild bird origin LPAIV precursor to the H7N7 HPAIV outbreak. Identifying a precursor LPAIV is important for understanding the molecular changes and mechanisms involved in the emergence of HPAIV. This information can lead to understanding how and why only some H7 LPAIVs appear to readily mutate to HPAIV.


Assuntos
Galinhas , Surtos de Doenças , Vírus da Influenza A Subtipo H7N7/genética , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Mutação , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/virologia , Animais , Genoma Viral , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A Subtipo H7N7/patogenicidade , Influenza Aviária/diagnóstico , Influenza Aviária/mortalidade , Filogenia , Doenças das Aves Domésticas/diagnóstico , Doenças das Aves Domésticas/mortalidade , Reino Unido/epidemiologia , Virulência , Sequenciamento Completo do Genoma
16.
Sci Rep ; 8(1): 8533, 2018 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-29867092

RESUMO

The objective of this study was to identify effective reporting thresholds for suspicions of both highly pathogenic (HPAI) and low pathogenic avian influenza (LPAI) outbreaks in layer farms. Daily mortality and egg-production data from 30 Dutch farms with no record of AI infection were analysed and thresholds set. Mortality rates above or egg-production below these thresholds for two consecutive days would trigger an alarm sign. The following thresholds were identified for mortality: (i) A mortality threshold of 0.08% or 0.13% for layers kept indoors or with free-range access respectively, (ii) a 2.9 times higher mortality than the average weekly mortality of the previous week, and iii) a moving-average threshold that could be implemented for each specific farm. For egg-production: (i) a weekly ratio lower than 0.94 in egg-production drop, and (ii) a moving-average threshold. The accuracy of these thresholds was assessed by quantifying their sensitivity, specificity and time to trigger disease detection using data from 15 infected and 31 non-infected farms. New thresholds were more sensitive and signalled infection two to six days earlier than the presently used thresholds. A high Specificity (97-100%) was obtained by combining mortality and egg production thresholds in a serial approach to trigger an alarm.


Assuntos
Criação de Animais Domésticos/métodos , Galinhas/virologia , Notificação de Doenças , Influenza Aviária , Doenças das Aves Domésticas , Animais , Feminino , Influenza Aviária/diagnóstico , Influenza Aviária/mortalidade , Influenza Aviária/prevenção & controle , Óvulo , Doenças das Aves Domésticas/diagnóstico , Doenças das Aves Domésticas/mortalidade , Doenças das Aves Domésticas/prevenção & controle
17.
Vet Microbiol ; 219: 8-16, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29778208

RESUMO

Avian influenza and infectious laryngeotracheitis viruses are common causes of respiratory diseases in chickens with economical importance worldwide. In this study, we investigated the effect of experimental co-infection of avian influenza virus-H9N2 (AIV-H9N2) with infectious laryngeotracheitis virus (ILTV) live-attenuated vaccine (LAR-VAC®) on chickens. Four experimental groups were included in this study: negative control group, AIV-H9N2 group, AIV-H9N2+LAR-VAC® group, and LAR-VAC® group. AIV-H9N2 was inoculated intranasally to challenged groups at 35 days of age. On the same day, LAR-VAC® was ocularly administered to vaccinated groups. Chickens were observed for clinical signs, changes in body weight and mortality rates. Tissue samples, sera, tracheal and cloacal swabs, and blood were also collected at 3, 6, 9 and 12 days post-infection (PI). A significant increase in clinical signs and mortality rates were observed in the AIV-H9N2 + LAR-VAC® group. Moreover, chickens coinfected with AIV-H9N2 and LAR-VAC® showed a significant decrease in body weight and lymphoid organs indices. The tracheal gross and histopathological lesions and the shedding titer and period of AIV-H9N2 were significantly higher in AIV-H9N2 + LAR-VAC® group when compared to other groups. Furthermore, AIV-H9N2 infection leads to humoral and cellular immunosuppression as shown by a significant decrease in the CD4+/CD8+ ratio and antibody responses to ILTV and a significant increase in H/L ratio. In conclusion, this is the first report of co-infection of AIV-H9N2 and ILTV vaccine in chickens, which leads to increased pathogenicity, pathological lesions, and AIV-H9N2 shedding titer and period, which can lead to severe economic losses due to poor weight gain and mortality.


Assuntos
Coinfecção/veterinária , Influenza Aviária/virologia , Laringite/veterinária , Traqueíte/veterinária , Vacinação/efeitos adversos , Vacinas Atenuadas/efeitos adversos , Animais , Anticorpos Antivirais/sangue , Galinhas/imunologia , Galinhas/virologia , Coinfecção/imunologia , Coinfecção/virologia , Imunidade Celular , Imunidade Humoral , Imunossupressão , Vírus da Influenza A Subtipo H9N2/isolamento & purificação , Vírus da Influenza A Subtipo H9N2/patogenicidade , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/etiologia , Influenza Aviária/imunologia , Influenza Aviária/mortalidade , Laringite/prevenção & controle , Laringite/virologia , Doenças das Aves Domésticas/virologia , Traqueíte/prevenção & controle , Traqueíte/virologia , Vacinas Atenuadas/administração & dosagem , Eliminação de Partículas Virais
18.
Avian Pathol ; 47(3): 314-324, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29517282

RESUMO

Respiratory diseases are responsible for major economic losses in poultry farms. While in most cases a single pathogen is not alone responsible for the clinical outcome, the impact of co-infections is not well known, especially in turkeys. The purpose of this study was to assess the possible synergism between Escherichia coli (O78) and low pathogenic avian influenza virus (LPAIV, H6N1), in the turkey model. Four-week-old commercial turkeys were inoculated with either H6N1, O78 or both agents simultaneously or three days apart. We have established an experimental infection model of turkeys using aerosolization that better mimics field infections. Birds were observed clinically and swabbed on a daily basis. Necropsies were performed at 4 and 14 days post single or dual inoculation and followed by histological and immunohistochemical analyses. Combined LPAIV/E. coli infections resulted in more severe clinical signs, were associated with higher mortality and respiratory organ lesions (mucous or fibrinous exudative material in lungs and air sacs), in comparison with the groups given single infections (P < 0.05). The time interval or the sequence between H6N1 and E. coli inoculation (none or three days) did not have a significant effect on the outcome of the dual infection and disease although slightly greater (P > 0.05) respiratory signs were observed in turkeys of the E. coli followed by H6N1 inoculated group. Microscopic lesions and immunohistochemical staining supported clinical and macroscopic findings. Efficient virus and bacteria replication was observed in all inoculated groups. E. coli and H6N1 thus exercise an additive or synergistic pathogenic effect in the reproduction of respiratory disease.


Assuntos
Infecções por Escherichia coli/veterinária , Escherichia coli/fisiologia , Vírus da Influenza A/fisiologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/microbiologia , Perus/microbiologia , Animais , Coinfecção/veterinária , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/mortalidade , Infecções por Escherichia coli/patologia , Feminino , Influenza Aviária/mortalidade , Influenza Aviária/patologia , Masculino , Doenças das Aves Domésticas/mortalidade , Doenças das Aves Domésticas/patologia
19.
Arch Virol ; 163(5): 1195-1207, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29392495

RESUMO

From 29 November 2016 to 24 January 2017, sixty-three cases of H5N6 highly pathogenic avian influenza virus (HPAIV) infections were detected in wild birds in Ibaraki Prefecture, Japan. Here, we analyzed the genetic, temporal, and geographic correlations of these 63 HPAIVs to elucidate their dissemination throughout the prefecture. Full-genome sequence analysis of the Ibaraki isolates showed that 7 segments (PB2, PB1, PA, HA, NP, NA, NS) were derived from G1.1.9 strains while the M segment was from G1.1 strains; both groups of strains circulated in south China. Pathological studies revealed severe systemic infection in dead swans (the majority of dead birds and the only species necropsied), thus indicating high susceptibility to H5N6 HPAIVs. Coalescent phylogenetic analysis using the 7 G1.1.9-derived segments enabled detailed analysis of the short-term evolution of these highly homologous HPAIVs. This analysis revealed that the H5N6 HPAIVs isolated from wild birds in Ibaraki Prefecture were divided into 7 groups. Spatial analysis demonstrated that most of the cases concentrated around Senba Lake originated from a single source, and progeny viruses were transmitted to other locations after the infection expanded in mute swans. In contrast, within just a 5-km radius of the area in which cases were concentrated, three different intrusions of H5N6 HPAIVs were evident. Multi-segment analysis of short-term evolution showed that not only was the invading virus spread throughout Ibaraki Prefecture but also that, despite the small size of this region, multiple invasions had occurred during winter 2016-2017.


Assuntos
Aves/virologia , Genoma Viral , Vírus da Influenza A/patogenicidade , Influenza Aviária/transmissão , Influenza Aviária/virologia , Animais , Animais Selvagens/virologia , Galinhas/virologia , Patos/virologia , Vírus da Influenza A/genética , Influenza Aviária/epidemiologia , Influenza Aviária/mortalidade , Japão/epidemiologia , Filogenia , Vírus Reordenados/genética , Vírus Reordenados/patogenicidade , Análise de Sequência de DNA
20.
Euro Surveill ; 23(4)2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29382414

RESUMO

IntroductionHighly pathogenic avian influenza (HPAI) viruses of subtype H5N8 were re-introduced into the Netherlands by late 2016, after detections in south-east Asia and Russia. This second H5N8 wave resulted in a large number of outbreaks in poultry farms and the deaths of large numbers of wild birds in multiple European countries. Methods: Here we report on the detection of HPAI H5N8 virus in 57 wild birds of 12 species sampled during active (32/5,167) and passive (25/36) surveillance activities, i.e. in healthy and dead animals respectively, in the Netherlands between 8 November 2016 and 31 March 2017. Moreover, we further investigate the experimental approach of wild bird serology as a contributing tool in HPAI outbreak investigations. Results: In contrast to the first H5N8 wave, local virus amplification with associated wild bird mortality has occurred in the Netherlands in 2016/17, with evidence for occasional gene exchange with low pathogenic avian influenza (LPAI) viruses. Discussion: These apparent differences between outbreaks and the continuing detections of HPAI viruses in Europe are a cause of concern. With the current circulation of zoonotic HPAI and LPAI virus strains in Asia, increased understanding of the drivers responsible for the global spread of Asian poultry viruses via wild birds is needed.


Assuntos
Animais Selvagens/virologia , Aves/virologia , Surtos de Doenças/veterinária , Vírus da Influenza A Subtipo H5N8/isolamento & purificação , Vírus da Influenza A Subtipo H5N8/patogenicidade , Influenza Aviária/mortalidade , Animais , Vírus da Influenza A Subtipo H5N8/classificação , Vírus da Influenza A Subtipo H5N8/genética , Influenza Aviária/patologia , Influenza Aviária/virologia , Países Baixos/epidemiologia , RNA Viral/genética , Vigilância de Evento Sentinela , Análise de Sequência de DNA
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