Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 196
Filtrar
1.
Biosens Bioelectron ; 143: 111632, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31479987

RESUMO

We present a sunlight based handheld smartphone spectrometer. The device first gathers the sunlight to pass through the sample, and then the transmitted light illuminates on a grating to generate spectrum finally recorded by the smartphone monochrome camera. All the optical elements are assembled with the smartphone to integrate a handheld device with the size of 140.2 mm × 67.4 mm × 80.5 mm. Besides, a smartphone application is also developed for automatic spectral calibration, detection, analysis and display. Compared to the white light emitting diode and the halogen lamp, the sunlight has more uniform distribution covering the entire visible spectral range; and the proposed device also avoids the bulky sizes of those broadband light sources. Additionally, the monochrome camera is used instead of the color camera not only to pursue a high spectral resolution as 0.276 nm/pixel but also to avoid the color overlapping. We demonstrate the device capability on detecting avian influenza virus H7N9 and porcine circovirus type 2 antibodies, proving the device has rather high sensitivity similar to the commercial microplate reader. Considering its advantages as compact size, high spectral resolution and detecting sensitivity, it is believed the proposed sunlight based handheld smartphone spectrometer is potential to be broadly applied in on-site detections.


Assuntos
Técnicas Biossensoriais , Circovirus/isolamento & purificação , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Smartphone , Animais , Aves/virologia , Circovirus/patogenicidade , Colorimetria , Humanos , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Aviária/diagnóstico , Influenza Aviária/virologia , Refratometria , Análise Espectral , Luz Solar , Suínos , Doenças dos Suínos/diagnóstico , Doenças dos Suínos/virologia
2.
Virus Genes ; 55(6): 739-768, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31428925

RESUMO

Avian influenza viruses (AIVs) circulate globally, spilling over into domestic poultry and causing zoonotic infections in humans. Fortunately, AIVs are not yet capable of causing sustained human-to-human infection; however, AIVs are still a high risk as future pandemic strains, especially if they acquire further mutations that facilitate human infection and/or increase pathogenesis. Molecular characterization of sequencing data for known genetic markers associated with AIV adaptation, transmission, and antiviral resistance allows for fast, efficient assessment of AIV risk. Here we summarize and update the current knowledge on experimentally verified molecular markers involved in AIV pathogenicity, receptor binding, replicative capacity, and transmission in both poultry and mammals with a broad focus to include data available on other AIV subtypes outside of A/H5N1 and A/H7N9.


Assuntos
Marcadores Genéticos/genética , Influenza Aviária/genética , Influenza Humana/genética , Zoonoses/genética , Animais , Aves/genética , Aves/virologia , Farmacorresistência Viral/genética , Humanos , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/patogenicidade , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Influenza Humana/virologia , Pandemias , Aves Domésticas/genética , Aves Domésticas/virologia , Zoonoses/virologia
4.
Influenza Other Respir Viruses ; 13(5): 496-503, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31187583

RESUMO

BACKGROUND: Highly pathogenic avian influenza (HPAI) A(H7N9) virus emerged and caused human infections during the 2016-2017 epidemic wave of influenza A(H7N9) viruses in China. We report a human infection with HPAI H7N9 virus and six environmental isolates in Fujian Province, China. METHODS: Environmental surveillance was conducted in live poultry markets and poultry farms in Fujian, China. Clinical and epidemiologic data and samples were collected. Real-time RT-PCRs were conducted for each sample, and H7-positive samples were isolated using embryonated chicken eggs. Full genomes of the isolates were obtained by next-generation sequencing. Phylogenetic analysis and antigenic analysis were conducted. RESULTS: A 59-year-old man who raised about 1000 ducks was identified as HPAI H7N9 infection. Six HPAI H7 viruses were isolated from environmental samples, including five H7N9 viruses and one H7N6 virus. Phylogenetic results showed the human and environmental viruses are highly genetically diverse and containing significantly different gene constellation from that of other HPAI H7N9 previously reported. The internal genes derived from H7N9/H9N2, H5N6, and the Eurasian wild-bird gene pool, indicating waterfowl-originated genotypes, have emerged in HPAI H7N9/N6 viruses and caused human infection. CONCLUSION: The new genotypes raise the concern that these HPAI H7 viruses might transmit back into migratory birds and spread to other countries as the HPAI H5Nx viruses. Considering their capability of causing severe infections in both human and poultry, the HPAI H7 viruses in this study pose a risk to public health and the poultry industry and highlight the importance of sustained surveillance of these viruses.


Assuntos
Patos/virologia , Genoma Viral , Subtipo H7N9 do Vírus da Influenza A/genética , Influenza Aviária/transmissão , Influenza Humana/epidemiologia , Animais , China/epidemiologia , Epidemias , Monitoramento Epidemiológico , Humanos , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Masculino , Pessoa de Meia-Idade , Filogenia , Aves Domésticas/virologia , Doenças das Aves Domésticas/virologia , Saúde Pública
5.
Biomed Res Int ; 2019: 2121357, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31080811

RESUMO

Background: cIAP2 is involved in necroptosis as a key upstream regulation factor. We aimed to investigate the role of cIAP2 in ARDS/ALI induced by H7N9 virus through regulating the RIPK1/3 necroptosis pathway. Methods: Lung tissues of 11 patients who died from ARDS-complicated H7N9 infection between 2013 and 2016 were obtained as the H7N9-ARDS group. Lung tissues near benign lung nodules were acquired as the control group. Histological changes were evaluated by H&E staining. Protein levels of cIAP2, RIPK1, RIPK3, p-RIPK3, MLKL, and p-MLKL in the lung tissues were detected by Western Blot. The mRNA levels of cIAP2, RIPK1, and RIPK3 were detected by real-time PCR. Results: H7N9 virus infection had a high mortality, with ARDS being the leading cause of death. The protein level of cIAP2 in the experimental group was lower than that in the control group (P<0.05). However, the experimental group showed higher RIPK1, RIPK3, and p-RIPK3 protein levels than the control group (P<0.05), as well as the expression level of MLKL and p-MLKL protein, which is a key downstream protein in necroptosis (P<0.05). Conclusion: In tissues from patients with fatal H7N9, downregulation of cIAP2 and induction of necroptosis was observed. We could speculate that necroptosis of the pulmonary epithelium is associated with severe H7N9 infection leading to ARDS. Thus, necroptosis inhibition may be a novel therapy for H7N9 influenza virus.


Assuntos
Proteína 3 com Repetições IAP de Baculovírus/metabolismo , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Síndrome do Desconforto Respiratório do Adulto/metabolismo , Síndrome do Desconforto Respiratório do Adulto/virologia , Adulto , Idoso , Animais , Células Cultivadas , Regulação para Baixo/fisiologia , Feminino , Humanos , Pulmão/metabolismo , Pulmão/virologia , Masculino , Camundongos , Pessoa de Meia-Idade , Necrose/metabolismo , Necrose/virologia , Mucosa Respiratória/metabolismo , Mucosa Respiratória/virologia
6.
PLoS One ; 14(4): e0215857, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31002703

RESUMO

BACKGROUND: From 2013 to 2017, more than one thousand avian influenza A (H7N9) confirmed cases with hundreds of deaths were reported in mainland China. To identify priorities for epidemic prevention and control, a risk assessing framework for subnational variations is needed to define the epidemic potential of A (H7N9). METHODS: We established a consolidated two-stage framework that outlined the potential epidemic of H7N9 in humans: The Stage 1, index-case potential, used a Boosted Regression Trees model to assess population at risk due to spillover from poultry; the Stage 2, epidemic potential, synthesized the variables upon a framework of the Index for Risk Management to measure epidemic potential based on the probability of hazards and exposure, the vulnerability and coping capacity. RESULTS: Provinces in southern and eastern China, especially Jiangsu, Zhejiang, Guangzhou, have high index-case potential of human infected with A (H7N9), while northern coastal provinces and municipalities with low morbidity, i.e. Tianjin and Liaoning, have an increasing risk of A (H7N9) infection. Provinces in central China are likely to have high potential of epidemic due to the high vulnerability and the lack of coping capacity. CONCLUSIONS: This study provides a unified risk assessment of A (H7N9) to detect the two-stage heterogeneity of epidemic potential among different provinces in mainland China, allowing proactively evaluate health preparedness at subnational levels to improve surveillance, diagnostic capabilities, and health promotion.


Assuntos
Epidemias/prevenção & controle , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Humana/epidemiologia , Modelos Estatísticos , Doenças das Aves Domésticas/epidemiologia , Animais , Aves , China/epidemiologia , Feminino , Humanos , Incidência , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Influenza Humana/prevenção & controle , Influenza Humana/transmissão , Influenza Humana/virologia , Masculino , Densidade Demográfica , Aves Domésticas , Doenças das Aves Domésticas/transmissão , Doenças das Aves Domésticas/virologia , Medição de Risco , Tempo (Meteorologia)
8.
Emerg Microbes Infect ; 8(1): 94-102, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30866763

RESUMO

There was a substantial increase with infections of H7N9 avian influenza virus (AIV) in humans during Wave 5 (2016-2017). To investigate whether H7N9 had become more infectious/transmissible and pathogenic overall, we characterized the receptor binding and experimentally infected ferrets with highly pathogenic (HP)- and low pathogenic (LP)-H7N9 isolates selected from Wave 5, and compared their pathogenicity and transmissibility with a Wave 1 isolate from 2013. Studies show that A/Anhui/1/2013 (LP) and A/Chicken/Heyuan/16876/2016 (HP) were highly virulent in ferrets, A/Guangdong/Th008/2017 (HP) and A/Chicken/Huizhou/HZ-3/2017 (HP) had moderate virulence and A/Shenzhen/Th001/2016 (LP) was of low virulence in ferrets. Transmission was observed only in ferrets infected with A/Anhui/1/2013 and A/Chicken/Heyuan/16876/2016, consistent with the idea that sicker ferrets had a higher probability to transmit virus to naive animals. Given the Varied virulence and transmissibility observed in circulating H7N9 viruses from Wave 5, we conclude that the current public health risk of H7N9 has not substantially increased compared to 2013 and the circulating viruses are quite diverse.


Assuntos
Furões/virologia , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Infecções por Orthomyxoviridae/transmissão , Receptores de Superfície Celular/metabolismo , Proteínas Virais/metabolismo , Animais , Genótipo , Humanos , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Subtipo H7N9 do Vírus da Influenza A/metabolismo , Influenza Humana/virologia , Nariz/virologia , Infecções por Orthomyxoviridae/virologia , Faringe/virologia , Virulência
9.
Bull Exp Biol Med ; 166(5): 631-636, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30903496

RESUMO

We compared three cold-adapted live attenuated influenza vaccine strains prepared by reverse genetics methods on the basis of master donor virus A/Leningrad/134/17/57 and influenza H7N9 strains A/Anhui/1/2013 and A/Shanghai/1/2013. Two strains based on A/Anhui/1/2013 differed by amino acid positions 123 and 149 in HA1 (123N/149N; 123D/149D). All strains efficiently replicated in developing chicken embryos; A/Shanghai/1/2013-based strain and A/Anhui/1/2013-123N/149N variant were characterized by reduced replication in MDCK cells. Strains based on A/Anhui/1/2013 virus agglutinated erythrocytes with α2,3- and α2,6-linked sialic acid residues, whereas strain A/Shanghai/1/2013 only α2,3. In experiments with BALB/c mice, Anhui-123D/149D strain was most immunogenic and induced high crossreactive humoral immune response, therefore it can be recommended as the model virus for the construction of recombinant vector vaccines based on live attenuated influenza vaccine.


Assuntos
Subtipo H7N9 do Vírus da Influenza A/imunologia , Substituição de Aminoácidos , Animais , Hemaglutininas/química , Hemaglutininas/imunologia , Humanos , Imunidade Humoral , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Vacinas contra Influenza/química , Vacinas contra Influenza/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Vacinas Atenuadas/química , Vacinas Atenuadas/imunologia
10.
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
11.
Viruses ; 11(2)2019 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-30813415

RESUMO

Highly pathogenic avian influenza (HPAI) H5N1 and low pathogenic avian influenza (LPAI) H7N9 viruses pose a severe threat to public health through zoonotic infection, causing severe respiratory disease in humans. While HPAI H5N1 human infections have typically been reported in Asian countries, avian H7N9 human infections have been reported mainly in China. However, Canada reported a case of fatal human infection by the HPAI H5N1 virus in 2014, and two cases of human illness associated with avian H7N9 virus infection in 2015. While the genomes of the causative viruses A/Alberta/01/2014 (H5N1) (AB14 (H5N1)) and A/British Columbia/1/2015 (H7N9) (BC15 (H7N9)) are reported, the isolates had not been evaluated for their pathogenicity in animal models. In this study, we characterized the pathogenicity of AB14 (H5N1) and BC15 (H7N9) and found that both strain isolates are highly lethal in mice. AB14 (H5N1) caused systemic viral infection and erratic proinflammatory cytokine gene expression in different organs. In contrast, BC15 (H7N9) replicated efficiently only in the respiratory tract, and was a potent inducer for proinflammatory cytokine genes in the lungs. Our study provides experimental evidence to complement the specific human case reports and animal models for evaluating vaccine and antiviral candidates against potential influenza pandemics.


Assuntos
Virus da Influenza A Subtipo H5N1/patogenicidade , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Humana/virologia , Doença Relacionada a Viagens , Animais , Aves/virologia , Canadá/epidemiologia , Citocinas/genética , Citocinas/imunologia , Modelos Animais de Doenças , Feminino , Humanos , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Pulmão/virologia , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/patologia , Reação em Cadeia da Polimerase , Replicação Viral
12.
Viruses ; 11(2)2019 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-30781528

RESUMO

Low pathogenic avian influenza (LPAI) viruses can silently circulate in poultry and wild aquatic birds and potentially mutate into highly pathogenic avian influenza (HPAI) viruses. In the U.S., recent emergence and spread of H7N8 and H7N9 HPAI viruses not only caused devastating losses to domestic poultry but also underscored the capability of LPAI viruses to mutate into HPAI viruses. Therefore, in this study, we evaluated pathogenicity and transmissibility of H7N8 and H7N9 LPAI viruses (the progenitors of HPAI viruses) in chickens and turkeys. We also included H7N2 isolated from an outbreak of LPAI in commercial chickens. H7 viruses replicated more efficiently in the respiratory tract than in the gastrointestinal tract, suggesting that their replication is restricted to the upper respiratory tract. Specifically, H7N2 replicated most efficiently in two-week-old chickens and turkeys. In contrast, H7N8 replicated least efficiently in those birds. Further, replication of H7N2 and H7N9 was restricted in the upper respiratory tract of four-week-old specific-pathogen-free (SPF) and broiler chickens. Despite their restricted replication, the two viruses efficiently transmitted from infected to naïve birds by direct contact, leading to seroconversion of contacted chickens. Our findings suggest the importance of continuous monitoring and surveillance of LPAI viruses in the fields.


Assuntos
Galinhas/virologia , Vírus da Influenza A/patogenicidade , Influenza Aviária/transmissão , Doenças das Aves Domésticas/transmissão , Perus/virologia , Replicação Viral , Animais , Trato Gastrointestinal/virologia , Vírus da Influenza A Subtipo H7N2/patogenicidade , Vírus da Influenza A Subtipo H7N2/fisiologia , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Sistema Respiratório/virologia , Organismos Livres de Patógenos Específicos
13.
Chin Med J (Engl) ; 132(3): 302-310, 2019 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-30681496

RESUMO

BACKGROUND: Six epidemic waves of human infection with avian influenza A (H7N9) virus have emerged in China with high mortality. However, study on quantitative relationship between clinical indices in ill persons and H7N9 outcome (fatal and non-fatal) is still unclear. A retrospective cohort study was conducted to collect laboratory-confirmed cases with H7N9 viral infection from 2013 to 2015 in 23 hospitals across 13 cities in Guangdong Province, China. METHODS: Multivariable logistic regression model and classification tree model analyses were used to detect the threshold of selected clinical indices and risk factors for H7N9 death. The receiver operating characteristic curve (ROC) and analyses were used to compare survival and death distributions and differences between indices. A total of 143 cases with 90 survivors and 53 deaths were investigated. RESULTS: Average age (Odds Ratio (OR) = 1.036, 95% Confidence Interval (CI) = 1.016-1.057), interval days between dates of onset and confirmation (OR = 1.078, 95% CI = 1.004-1.157), interval days between onset and oseltamivir treatment (OR = 5.923, 95% CI = 1.877-18.687), body temperature (BT) (OR = 3.612, 95% CI = 1.914-6.815), white blood cell count (WBC) (OR = 1.212, 95% CI = 1.092-1.346) were significantly associated with H7N9 death after adjusting for confounders. The chance of death from H7N9 infection was 80.0% if BT was over 38.1 °C, and chance of death is 67.4% if WBC count was higher than 9.5 (10/L). Only 27.1% of patients who began oseltamivir treatment less than 9.5 days after disease onset died, compared to 68.8% of those who started treatment more than 15.5 days after onset. CONCLUSIONS: The intervals between date of onset and confirmation of diagnosis, between date of onset to oseltamivir treatment, age, BT and WBC are found to be the best predictors of H7N9 mortality.


Assuntos
Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Humana/epidemiologia , Influenza Humana/mortalidade , Adulto , Idoso , China/epidemiologia , Intervalos de Confiança , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Influenza Humana/virologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Curva ROC , Estudos Retrospectivos , Fatores de Risco , Adulto Jovem
14.
Arch Virol ; 164(3): 807-817, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30671655

RESUMO

The emergent highly pathogenic avian influenza A (H7N9) (HPAI) virus is a major public concern in China. Therefore, it is crucially important to develop an effective vaccine against this virus. In this study, we constructed a baculovirus vaccine expressing the hemagglutinin (HA) of H7N9 strain A/Chicken/Jiaxing/148/2014 (JX148). The recombinant baculovirus (rBac-JX148HA) generated in this study showed good growth in insect cells and good safety, and it stably expressed the HA protein. We compared the immunogenicity and efficacy of the inactivated whole-virus vaccine JX148 and rBac-JX148HA. One chicken in the JX148-treated group died on day 4 post-challenge, and three chickens had typical clinical symptoms (survival rate, 90%; morbidity, 40%). However, no chickens immunized with rBac-JX148HA showed clinical signs during the 14-day observation period. An analysis of viral shedding and viral replication demonstrated that rBac-JX148HA more efficiently inhibited viral shedding and viral replication than the inactivated whole-virus vaccine. Taken together, these results indicate that the inactivated recombinant baculovirus vaccine induces a high hemagglutination inhibition antibody titer, provides complete protection against challenge with the highly pathogenic H7N9 virus, and effectively inhibits viral shedding. Therefore, the candidate vaccine has potential utility in the prevention and control of H7N9 avian influenza and is also appropriate for veterinary vaccines using cell suspension culture technology.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/administração & dosagem , Subtipo H7N9 do Vírus da Influenza A/imunologia , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Animais , Anticorpos Antivirais/imunologia , Baculoviridae/genética , Baculoviridae/metabolismo , Galinhas , China , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/genética , Vacinas contra Influenza/imunologia , Influenza Aviária/imunologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/virologia , Vacinação , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Virulência , Eliminação de Partículas Virais
15.
Vector Borne Zoonotic Dis ; 19(1): 22-25, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30222520

RESUMO

The low pathogenic avian influenza A(H7N9) viruses (LPAI) were first identified in 2013 and have continued to infect humans since then. It was reported in February 2017 that the LPAI H7N9 virus has evolved into highly pathogenic avian influenza (HPAI) viruses, potentially increasing the risk for human and poultry. We in this study overviewed the emergence, epidemiology, and biological characterizations of the HPAI H7N9 viruses for the risk assessment.


Assuntos
Aves , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Influenza Humana/virologia , Animais , Antivirais/farmacologia , China/epidemiologia , Farmacorresistência Viral , Humanos , Subtipo H7N9 do Vírus da Influenza A/efeitos dos fármacos , Subtipo H7N9 do Vírus da Influenza A/genética , Influenza Aviária/epidemiologia , Influenza Humana/epidemiologia , Fatores de Risco
16.
J Virol ; 93(1)2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30305359

RESUMO

The fifth wave of the H7N9 influenza epidemic in China was distinguished by a sudden increase in human infections, an extended geographic distribution, and the emergence of highly pathogenic avian influenza (HPAI) viruses. Genetically, some H7N9 viruses from the fifth wave have acquired novel amino acid changes at positions involved in mammalian adaptation, antigenicity, and hemagglutinin cleavability. Here, several human low-pathogenic avian influenza (LPAI) and HPAI H7N9 virus isolates from the fifth epidemic wave were assessed for their pathogenicity and transmissibility in mammalian models, as well as their ability to replicate in human airway epithelial cells. We found that an LPAI virus exhibited a similar capacity to replicate and cause disease in two animal species as viruses from previous waves. In contrast, HPAI H7N9 viruses possessed enhanced virulence, causing greater lethargy and mortality, with an extended tropism for brain tissues in both ferret and mouse models. These HPAI viruses also showed signs of adaptation to mammalian hosts by acquiring the ability to fuse at a lower pH threshold than other H7N9 viruses. All of the fifth-wave H7N9 viruses were able to transmit among cohoused ferrets but exhibited a limited capacity to transmit by respiratory droplets, and deep sequencing analysis revealed that the H7N9 viruses sampled after transmission showed a reduced amount of minor variants. Taken together, we conclude that the fifth-wave HPAI H7N9 viruses have gained the ability to cause enhanced disease in mammalian models and with further adaptation may acquire the ability to cause an H7N9 pandemic.IMPORTANCE The potential pandemic risk posed by avian influenza H7N9 viruses was heightened during the fifth epidemic wave in China due to the sudden increase in the number of human infections and the emergence of antigenically distinct LPAI and HPAI H7N9 viruses. In this study, a group of fifth-wave HPAI and LPAI viruses was evaluated for its ability to infect, cause disease, and transmit in small-animal models. The ability of HPAI H7N9 viruses to cause more severe disease and to replicate in brain tissues in animal models as well as their ability to fuse at a lower pH threshold than LPAI H7N9 viruses suggests that the fifth-wave H7N9 viruses have evolved to acquire novel traits with the potential to pose a higher risk to humans. Although the fifth-wave H7N9 viruses have not yet gained the ability to transmit efficiently by air, continuous surveillance and risk assessment remain essential parts of our pandemic preparedness efforts.


Assuntos
Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Humana/virologia , Infecções por Orthomyxoviridae/epidemiologia , RNA Viral/genética , Análise de Sequência de RNA/métodos , Animais , Linhagem Celular , China/epidemiologia , Epidemias , Evolução Molecular , Furões , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Subtipo H7N9 do Vírus da Influenza A/genética , Influenza Humana/epidemiologia , Influenza Humana/transmissão , Camundongos , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia , Medição de Risco , Células Vero , Tropismo Viral , Virulência
17.
Arch Virol ; 164(2): 535-545, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30539262

RESUMO

Human infection by low-pathogenic avian influenza viruses of the H7N9 subtype was first reported in March 2013 in China. Subsequently, these viruses caused five outbreaks through September 2017. In the fifth outbreak, H7N9 virus possessing a multiple basic amino acid insertion in the cleavage site of hemagglutinin emerged and caused 4% of all human infections in that period. To date, H7N9 highly pathogenic avian influenza viruses (HPAIVs) have been isolated from poultry, mostly chickens, as well as the environment. To evaluate the relative infectivity of these viruses in poultry, chickens and ducks were subjected to experimental infection with two H7N9 HPAIVs isolated from humans, namely A/Guangdong/17SF003/2016 and A/Taiwan/1/2017. When chickens were inoculated with the HPAIVs at a dose of 106 50% egg infectious dose (EID50), all chickens died within 2-5 days after inoculation, and the viruses replicated in most of the internal organs examined. The 50% lethal doses of A/Guangdong/17SF003/2016 and A/Taiwan/1/2017 in chickens were calculated as 103.3 and 104.7 EID50, respectively. Conversely, none of the ducks inoculated with either virus displayed any clinical signs, and less-efficient virus replication and less shedding were observed in ducks compared to chickens. These findings indicate that chickens, but not ducks, are highly permissive hosts for emerging H7N9 HPAIVs.


Assuntos
Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Influenza Humana/virologia , Doenças das Aves Domésticas/virologia , Sequência de Aminoácidos , Animais , Galinhas , Patos , Humanos , Subtipo H7N9 do Vírus da Influenza A/classificação , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Filogenia , Homologia de Sequência de Aminoácidos , Proteínas Virais/química , Proteínas Virais/genética , Virulência
18.
Trends Microbiol ; 27(2): 93-95, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30553653

RESUMO

Novel highly pathogenic avian influenza (HPAI) H7N9 viruses of the fifth epidemic wave infect humans and poultry. Recently, HPAI H7N9 viruses have evolved into different subtypes and genotypes, exhibited heightened virulence in mammals, and extended their host range, thereby posing a potential threat to public health and the poultry industry.


Assuntos
Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Animais , Epidemias , Evolução Molecular , Genótipo , Especificidade de Hospedeiro , Humanos , Influenza Aviária/transmissão , Influenza Humana/epidemiologia , Influenza Humana/virologia , Infecções por Orthomyxoviridae/virologia , Aves Domésticas , Saúde Pública , Virulência/genética , Replicação Viral
19.
Artigo em Inglês | MEDLINE | ID: mdl-30533399

RESUMO

Since 2013, the H7N9 avian influenza A virus (AIV) has caused human infections and to the extent of now surpassing H5N1. This raises an alarm about the potential of H7N9 to become a pandemic problem. Our compilation of the amino acid changes required for AIVs to cross the species-barrier discovers 58 that have very high proportions in both the human- and avian-isolated H7N9 viruses. These changes correspond with sporadic human infections that continue to occur in regions of avian infections. Among the six internal viral genes, amino acid changes do not differ significantly between H9N2 and H7N9, except for V100A in PA, and K526R, D627K, and D701N in PB2. H9N2 AIVs provide internal genes to H7N9. Most of the amino acid changes in H7N9 appear to come directly from H9N2. Seventeen amino acid substitutions appear to have fixed quickly by the 5th wave. Among these, six amino acid sites in HA1 are receptor binding sites, and PB2-A588V was shown to promote the adaptation of AIVs to mammals. The accelerated fixation of mutations may promote the adaptation of H7N9 to human, but need further functional evidence. Although H7N9 AIVs still cannot efficiently transmit between humans, they have the genetic makeup associated with human infections. These viruses must be controlled in poultry to remove the threat of it becoming a human pandemic event.


Assuntos
Substituição de Aminoácidos , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Influenza Humana/virologia , Pandemias , Análise de Sequência , Sequência de Aminoácidos , Animais , Genes Virais/genética , Humanos , Virus da Influenza A Subtipo H5N1/genética , Vírus da Influenza A Subtipo H9N2/genética , Modelos Moleculares , Proteínas Virais/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA