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1.
Nat Commun ; 11(1): 766, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32034144

RESUMO

Human influenza A viruses are known to be transmitted via the air from person to person. It is unknown from which anatomical site of the respiratory tract influenza A virus transmission occurs. Here, pairs of genetically tagged and untagged influenza A/H1N1, A/H3N2 and A/H5N1 viruses that are transmissible via the air are used to co-infect donor ferrets via the intranasal and intratracheal routes to cause an upper and lower respiratory tract infection, respectively. In all transmission cases, we observe that the viruses in the recipient ferrets are of the same genotype as the viruses inoculated intranasally, demonstrating that they are expelled from the upper respiratory tract of ferrets rather than from trachea or the lower airways. Moreover, influenza A viruses that are transmissible via the air preferentially infect ferret and human nasal respiratory epithelium. These results indicate that virus replication in the upper respiratory tract, the nasal respiratory epithelium in particular, of donors is a driver for transmission of influenza A viruses via the air.


Assuntos
Furões/virologia , Vírus da Influenza A/fisiologia , Mucosa Nasal/virologia , Infecções por Orthomyxoviridae/transmissão , Ar , Animais , Cães , Feminino , Humanos , Vírus da Influenza A/genética , Vírus da Influenza A/patogenicidade , Células Madin Darby de Rim Canino , Infecções por Orthomyxoviridae/veterinária , Tropismo Viral
2.
Emerg Microbes Infect ; 9(1): 88-94, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31900060

RESUMO

Infection with a novel H10N8 influenza virus in humans was first described in China in December 2013, which raised concerns related to public health. This novel virus was subsequently confirmed to have originated from a live poultry market. However, whether this virus can infect other mammals remains unclear. In the present study, antibody specific for H10N8 influenza virus was detected in swine herds in southern China during serological monitoring for swine influenza virus. The pathogenicity and transmissibility of this H10N8 influenza virus to swine was examined. The results showed that swine are susceptible to infection with human-origin H10N8 influenza virus, which causes viral shedding, severe tissue lesions, and seroconversion, while infection with avian-origin H10N8 influenza virus causes only seroconversion and no viral shedding. Importantly, human-origin H10N8 influenza virus can inefficiently be transmitted between swine and cause seroconversion through direct contact. This study provides a new perspective regarding the ecology of H10N8 influenza virus and highlights the importance of epidemiological monitoring of the H10N8 influenza virus in different animal species, which will be helpful for preventing and controlling future infections by this virus.


Assuntos
Vírus da Influenza A Subtipo H10N8/fisiologia , Infecções por Orthomyxoviridae/veterinária , Doenças dos Suínos/imunologia , Doenças dos Suínos/transmissão , Animais , Anticorpos Antivirais/imunologia , China , Humanos , Vírus da Influenza A Subtipo H10N8/patogenicidade , Pulmão/patologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/transmissão , Sus scrofa , Suínos , Doenças dos Suínos/patologia , Doenças dos Suínos/virologia , Zoonoses
3.
Am J Pathol ; 190(1): 11-24, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31654637

RESUMO

As influenza viruses continue to jump species barriers to cause human infection, assessments of disease severity and viral replication kinetics in vivo provide crucial information for public health professionals. The ferret model is a valuable resource for evaluating influenza virus pathogenicity; thus, understanding the most effective techniques for sample collection and usage, as well as the full spectrum of attainable data after experimental inoculation in this species, is paramount. This is especially true for scheduled necropsy of virus-infected ferrets, a standard component in evaluation of influenza virus pathogenicity, as necropsy findings can provide important information regarding disease severity and pathogenicity that is not otherwise available from the live animal. In this review, we describe the range of influenza viruses assessed in ferrets, the measures of experimental disease severity in this model, and optimal sample collection during necropsy of virus-infected ferrets. Collectively, this information is critical for assessing systemic involvement after influenza virus infection in mammals.


Assuntos
Modelos Animais de Doenças , Vírus da Influenza A/patogenicidade , Infecções por Orthomyxoviridae/prevenção & controle , Animais , Pesquisa Biomédica , Furões , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia
4.
Influenza Other Respir Viruses ; 13(6): 535-546, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31583825

RESUMO

Ferrets are a well-established model for studying both the pathogenesis and transmission of human respiratory viruses and evaluation of antiviral vaccines. Advanced immunological studies would add substantial value to the ferret models of disease but are hindered by the low number of ferret-reactive reagents available for flow cytometry and immunohistochemistry. Nevertheless, progress has been made to understand immune responses in the ferret model with a limited set of ferret-specific reagents and assays. This review examines current immunological insights gained from the ferret model across relevant human respiratory diseases, with a focus on influenza viruses. We highlight key knowledge gaps that need to be bridged to advance the utility of ferrets for immunological studies.


Assuntos
Modelos Animais de Doenças , Furões/imunologia , Infecções por Orthomyxoviridae/imunologia , Orthomyxoviridae/imunologia , Animais , Humanos , Imunidade/genética , Imunidade/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Influenza Humana/transmissão , Infecções por Orthomyxoviridae/prevenção & controle , Infecções por Orthomyxoviridae/transmissão , Viroses/imunologia , Viroses/prevenção & controle , Viroses/transmissão
5.
Influenza Other Respir Viruses ; 13(6): 564-573, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31541519

RESUMO

BACKGROUND: Bioaerosol sampling devices are necessary for the characterization of infectious bioaerosols emitted by naturally-infected hosts with acute respiratory virus infections. Assessment of these devices under multiple experimental conditions will provide insight for device use. OBJECTIVES: The primary objective of this study was to assess and compare bioaerosol sampling devices using a) an in vitro, environmentally-controlled artificial bioaerosol system at a range of different RH conditions and b) an in vivo bioaerosol system of influenza virus-infected ferrets under controlled environmental conditions. Secondarily, we also sought to examine the impact of NSAIDs on bioaerosol emission in influenza virus-infected ferrets to address its potential as a determinant of bioaerosol emission. METHODS: We examined the performance of low and moderate volume bioaerosol samplers for the collection of viral RNA and infectious influenza virus in vitroand in vivo using artificial bioaerosols and the ferret model of influenza virus infection. The following samplers were tested: the polytetrafluoroethylene filter (PTFE filter), the 2-stage National Institute of Occupational Safety and Health cyclone sampler (NIOSH cyclone sampler) and the 6-stage viable Andersen impactor (Andersen impactor). RESULTS: The PTFE filter and NIOSH cyclone sampler collected similar amounts of viral RNA and infectious virus from artificially-generated aerosols under a range of relative humidities (RH). Using the ferret model, the PTFE filter, NIOSH cyclone sampler and the Andersen impactor collected up to 3.66 log10 copies of RNA/L air, 3.84 log10 copies of RNA/L air and 6.09 log10 copies of RNA/L air respectively at peak recovery. Infectious virus was recovered from the PTFE filter and NIOSH cyclone samplers on the peak day of viral RNA recovery. CONCLUSION: The PTFE filter and NIOSH cyclone sampler are useful for influenza virus RNA and infectious virus collection and may be considered for clinical and environmental settings.


Assuntos
Aerossóis , Microbiologia do Ar , Vírus da Influenza A/isolamento & purificação , Infecções por Orthomyxoviridae/transmissão , Manejo de Espécimes/instrumentação , Animais , Anti-Inflamatórios não Esteroides/uso terapêutico , Modelos Animais de Doenças , Furões , Umidade , Vírus da Influenza A/genética , Infecções por Orthomyxoviridae/tratamento farmacológico , Infecções por Orthomyxoviridae/virologia , Tamanho da Partícula , RNA Viral/análise
6.
Emerg Microbes Infect ; 8(1): 1324-1336, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31503518

RESUMO

Avian influenza A viruses (AIV) of the H7 subtype continue to evolve posing a pandemic threat. However, molecular markers of H7N7 AIV pathogenicity and transmission in mammals remain poorly understood. In this study, we performed a systematic in vitro and in vivo analysis by comparing an H7N7 highly pathogenic AIV and its ferret adapted variant. Passaging an H7N7 AIV in ferrets led to six mutations in genes encoding the viral polymerase complex and the viral surface proteins. Here, we show that mutations in the H7 hemagglutinin gene cause increased pathogenicity in mice. Contact transmission between guinea pigs required additional mutations in the gene encoding the polymerase subunit PB1. Thus, particular vigilance is required with respect to HA and PB1 mutations as predictive molecular markers to assess the pandemic risk posed by emerging H7 avian influenza viruses.


Assuntos
Transmissão de Doença Infecciosa , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A Subtipo H7N7/patogenicidade , Proteínas Mutantes/genética , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia , Proteínas Virais/genética , Animais , Modelos Animais de Doenças , Furões , Cobaias , Vírus da Influenza A Subtipo H7N7/genética , Infecções por Orthomyxoviridae/patologia , Inoculações Seriadas , Fatores de Virulência/genética
7.
BMC Infect Dis ; 19(1): 762, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477028

RESUMO

BACKGROUND: Avian influenza A (H5N6) virus poses a great threat to the human health since it is capable to cross the species barrier and infect humans. Although human infections are believed to largely originate from poultry contaminations, the transmissibility is unclear and only limited information was available on poultry environment contaminations, especially in Fujian Province. METHODS: A total of 4901 environmental samples were collected and tested for Avian Influenza Virus (AIV) from six cities in Fujian Province through the Fujian Influenza Surveillance System from 2013 to 2017. Two patient-related samples were taken from Fujian's first confirmed H5N6 human case and his backyard chicken feces in 2017. Chi-square test or Fisher's exact probability test was used to compare the AIV and the viral subtype positive rates among samples from different Surveillance cities, surveillance sites, sample types, and seasons. Phylogenetic tree analysis and molecular analysis were conducted to track the viral transmission route of the human infection and to map out the evolutions of H5N6 in Fujian. RESULTS: The overall positive rate of the H5 subtype AIVs was 4.24% (208/4903). There were distinctive differences (p < 0.05) in the positive rates in samples from different cities, sample sites, sample types and seasons. The viruses from the patient and his backyard chicken feces shared high homologies (99.9-100%) in all the eight gene segments. Phylogenetic trees also showed that these two H5N6 viruses were closely related to each other, and were classified into the same genetic clade 2.3.4.4 with another six H5N6 isolates from the environmental samples. The patient's H5N6 virus carried genes from H6N6, H5N8 and H5N6 viruses originated from different areas. The R294K or N294S substitution was not detected in the neuraminidase (NA). The S31 N substitution in the matrix2 (M2) gene was detected but only in one strain from the environmental samples. CONCLUSIONS: The H5 subtype of AIVs has started circulating in the poultry environments in Fujian Province. The patient's viral strain originated from the chicken feces in his backyard. Genetic reassortment in H5N6 viruses in Fujian Province was indicated. The H5N6 viruses currently circulating in Fujian Province were still commonly sensitive to Oseltamivir and Zanamivir, but the resistance against Amantadine has emerged.


Assuntos
Vírus da Influenza A/isolamento & purificação , Influenza Aviária/virologia , Influenza Humana/epidemiologia , Influenza Humana/virologia , Infecções por Orthomyxoviridae/virologia , Aves Domésticas/virologia , Animais , Embrião de Galinha , Galinhas/virologia , China/epidemiologia , Patos/virologia , Meio Ambiente , Microbiologia Ambiental , Genes Virais , Abrigo para Animais/normas , Humanos , Vírus da Influenza A/genética , Influenza Aviária/diagnóstico , Influenza Aviária/epidemiologia , Tipagem Molecular , Infecções por Orthomyxoviridae/diagnóstico , Infecções por Orthomyxoviridae/epidemiologia , Infecções por Orthomyxoviridae/transmissão , Filogenia , Doenças das Aves Domésticas/diagnóstico , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/virologia , Fatores de Risco
8.
Environ Health Prev Med ; 24(1): 53, 2019 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-31421676

RESUMO

BACKGROUND: Influenza A viruses pose a significant risk to human health because of their wide host range and ability to reassort into novel viruses that can cause serious disease and pandemics. Since transmission of these viruses between humans and pigs can be associated with occupational and environmental exposures, we investigated the association between occupational exposure to pigs, occurrence of acute respiratory illness (ARI), and influenza A virus infection. METHODS: The study was conducted in Kiambu County, the county with the highest level of intensive small-scale pig farming in Kenya. Up to 3 participants (> 2 years old) per household from pig-keeping and non-pig-keeping households were randomly recruited and followed up in 2013 (Sept-Dec) and 2014 (Apr-Aug). Oropharyngeal (OP) and nasopharyngeal (NP) swabs were collected from participants with ARI at the time of study visit. For the animal study, nasal and oropharyngeal swabs, and serum samples were collected from pigs and poultry present in enrolled households. The human and animal swab samples were tested for viral nucleic acid by RT-PCR and sera by ELISA for antibodies. A Poisson generalized linear mixed-effects model was developed to assess the association between pig exposure and occurrence of ARI. RESULTS: Of 1137 human participants enrolled, 625 (55%) completed follow-up visits including 172 (27.5%) pig workers and 453 (72.5%) non-pig workers. Of 130 human NP/OP swabs tested, four (3.1%) were positive for influenza A virus, one pig worker, and three among non-pig workers. Whereas none of the 4462 swabs collected from pig and poultry tested positive for influenza A virus by RT-PCR, 265 of 4273 (6.2%) of the sera tested positive for virus antibodies by ELISA, including 11.6% (230/1990) of the pigs and 1.5% (35/2,283) of poultry. The cumulative incidence of ARI was 16.9% among pig workers and 26.9% among the non-pig workers. The adjusted risk ratio for the association between being a pig worker and experiencing an episode of ARI was 0.56 (95% CI [0.33, 0.93]), after adjusting for potential confounders. CONCLUSIONS: Our findings demonstrate moderate seropositivity for influenza A virus among pigs, suggesting the circulation of swine influenza virus and a potential for interspecies transmission.


Assuntos
Vírus da Influenza A/fisiologia , Influenza Humana/epidemiologia , Infecções por Orthomyxoviridae/epidemiologia , Zoonoses/epidemiologia , Adolescente , Adulto , Animais , Anticorpos Antivirais/sangue , Criança , Feminino , Humanos , Incidência , Vírus da Influenza A/genética , Vírus da Influenza A/imunologia , Influenza Humana/transmissão , Influenza Humana/virologia , Quênia/epidemiologia , Masculino , Pessoa de Meia-Idade , Infecções por Orthomyxoviridae/transmissão , Faringe/virologia , Aves Domésticas/virologia , RNA Viral/genética , Fatores de Risco , Estudos Soroepidemiológicos , Suínos/virologia , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/transmissão , Adulto Jovem , Zoonoses/transmissão
9.
Int J Infect Dis ; 88: 113-119, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31401200

RESUMO

Here we review evidence for influenza A viruses (IAVs) moving from swine, avian, feline, equine, and canine species to infect humans. We review case reports, sero-epidemiological, archeo-epidemiological, environmental, and historical studies and consider trends in livestock farming. Although this focused review is not systematic, the aggregated data point to industrialized swine farming as the most likely source of future pandemic viruses, yet IAV surveillance on such farms is remarkably sparse. We recommend increased biosafety and biosecurity training for farm administrators and swine workers with One Health-oriented virus surveillance throughout industrialized farming and meat production lines. Collaborative partnerships with human medical researchers could aid in efforts to mitigate emerging virus threats by offering new surveillance and diagnostic technologies to livestock farming industries.


Assuntos
Vírus da Influenza A/fisiologia , Influenza Humana/virologia , Infecções por Orthomyxoviridae/veterinária , Animais , Aves , Gatos , Cães , Cavalos , Humanos , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Influenza Humana/transmissão , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia , Suínos
10.
PLoS One ; 14(7): e0217607, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31323023

RESUMO

Southern China is considered an important source of influenza virus pandemics because of the large, diverse viral reservoirs in poultry and swine. To examine the trend in influenza A virus of swine (IAV-S), an active surveillance program has been conducted from 2013 to 2015 in Guangdong, China. The phylogenetic analyses showed that the external genes of the isolates were assigned to the Eurasian avian-like swine (EA) H1N1 and/or human-like H3N2 lineages with multiple substitutions, indicating a notable genetic shift. Moreover, the internal genes derived from different origins (PB2, PB1, PA, NP: pdm/09 (pandemic influenza virus 2009)-origin, M: pdm/09- or EA-origin, NS: North American Triple Reassortant (TR)-origin have become the dominant backbone of IAV-S in southern China. According to the origins of the eight gene segments, the isolates can be categorized into five genotypes. The results of mice experiment showed that the YJ4 (genotype 1) and DG2 (genotype 4) are the most pathogenic to mice, and the viruses are observed in kidneys and brains, indicating the systemic infection. The alterations of the IAV-S gene composition supported the continued implementation of the intensive surveillance of IAV-S and the greater attention focused on potential shifts toward transmission to humans.


Assuntos
Evolução Molecular , Genótipo , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H3N2/genética , Infecções por Orthomyxoviridae/genética , Doenças dos Suínos/genética , Animais , China , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/veterinária , Suínos , Doenças dos Suínos/transmissão , Doenças dos Suínos/virologia
11.
mBio ; 10(3)2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31113896

RESUMO

Despite efforts to control influenza virus infection and transmission, influenza viruses still cause significant morbidity and mortality in the global human population each year. Most of the current vaccines target the immunodominant hemagglutinin surface glycoprotein of the virus. However, reduced severity of disease and viral shedding have also been linked to antibodies targeting the second viral surface glycoprotein, the neuraminidase. Importantly, antineuraminidase immunity was shown to be relatively broad, in contrast to vaccine-induced antibodies to the hemagglutinin head domain. In this study, we assessed recombinant neuraminidase protein vaccination for its ability to prevent or limit virus transmission. We vaccinated guinea pigs either intramuscularly or intranasally with a recombinant influenza B virus neuraminidase to assess whether neuraminidase vaccination via these routes could prevent transmission of the homologous virus to a naive recipient. Guinea pigs vaccinated with neuraminidase showed reduced virus titers; however, only vaccination via the intranasal route fully prevented virus transmission to naive animals. We found high levels of antineuraminidase antibodies capable of inhibiting neuraminidase enzymatic activity in the nasal washes of intranasally vaccinated animals, which may explain the observed differences in transmission. We also determined that mucosal immunity to neuraminidase impaired the transmission efficiency of a heterologous influenza B virus, although to a lesser extent. Finally, we found that neuraminidase-vaccinated animals were still susceptible to infection via the airborne and contact transmission routes. However, significantly lower virus titers were detected in these vaccinated recipients. In summary, our data suggest that supplementing vaccine formulations with neuraminidase and vaccinating via the intranasal route may broadly prevent transmission of influenza B viruses.IMPORTANCE Recently, the protective effect of anti-neuraminidase immunity has been highlighted by several studies in humans and animal models. However, so far the role that anti-neuraminidase immunity plays in inhibition of virus transmission has not been explored. In addition, neuraminidase has been ignored as an antigen for influenza virus vaccines. We show here that neuraminidase-based vaccines can inhibit the transmission of influenza virus. Therefore, neuraminidase should be considered as an antigen for improved influenza virus vaccines that not only protect individuals from disease but also inhibit further spread of the virus in the population.


Assuntos
Transmissão de Doença Infecciosa/prevenção & controle , Imunidade nas Mucosas , Vírus da Influenza B/imunologia , Neuraminidase/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Infecções por Orthomyxoviridae/transmissão , Proteínas Virais/imunologia , Administração Intranasal , Animais , Modelos Animais de Doenças , Cobaias , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/imunologia , Injeções Intramusculares , Resultado do Tratamento , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia
12.
Trop Anim Health Prod ; 51(7): 2019-2024, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31041720

RESUMO

Influenza constitutes a challenge to animal and human health. It is a highly contagious disease with wildlife reservoirs and considered as endemic among swine populations. Pigs are crucial in the disease dynamics due to their capacity to generate new reassortant viruses. The risk of informal animal trade in the spread of zoonotic diseases is well recognized worldwide. Nevertheless, the contribution of the backyard pig trade network in the transmission of influenza in a wildlife/livestock interface area is unknown. This study provides the first simulation of influenza transmission based on backyard farm connections in Mexico. A susceptible-infectious-recovered (SIR) model was implemented using the Epimodel software package in R, and 260 backyard farms were considered as nodes. Three different scenarios of connectivity (low, medium, and high) mediated by trade were generated and compared. Our results suggest that half of the pig population were infected within 5 days in the high connectivity scenario and the number of infected farms was approximately 65-fold higher compared to the low connected one. The consequence of connectivity variations directly influenced both time and duration of influenza virus transmission. Therefore, high connectivity driven by informal trade constitutes a significant risk to animal health. Trade patterns of animal movements are complex. This approach emphasizes the importance of pig movements and spatial dynamics among backyard production, live animal markets, and wildlife.


Assuntos
Criação de Animais Domésticos , Vírus da Influenza A/fisiologia , Infecções por Orthomyxoviridae/veterinária , Doenças dos Suínos/transmissão , Animais , Animais Selvagens , Gado , México , Modelos Teóricos , Infecções por Orthomyxoviridae/transmissão , Sus scrofa , Suínos
13.
PLoS One ; 14(4): e0215478, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30990853

RESUMO

The infectious salmon anaemia virus (ISAV) is an important pathogen on farmed salmon in Europe. The virus occurs as low- and high virulent variants where the former seem to be a continuous source of new high virulent ISAV. The latter are controlled in Norway by stamping out infected populations while the former are spreading uncontrolled among farmed salmon. Evidence of vertical transmission has been presented, but there is still an ongoing discussion of the importance of circulation of ISAV via salmon brood fish. The only known wild reservoirs are in trout (Salmo trutta) and salmon (Salmo salar). This study provides the first ISAV sequences from wild salmonids in Norway and evaluates the importance of this reservoir with respect to outbreaks of ISA among farmed salmon. Phylogenetic analyses of the surface protein hemagglutinin-esterase gene from nearly all available ISAV from Norway, Faeroe Islands, Scotland, Chile and wild salmonids in Norway show that they group into four major clades. Including virulent variants in the analysis show that they belong in the same four clades supporting the hypothesis that there is a high frequency of transition from low to high virulent variants in farmed populations of salmon. There is little support for a hypothesis suggesting that the wild salmonids feed the virus into farmed populations. This study give support to earlier studies that have documented local horizontal transmission of high virulent ISAV, but the importance of transition from low- to high virulent variants has been underestimated. Evidence of vertical transmission and long distance spreading of ISAV via movement of embryos and smolt is presented. We recommend that the industry focus on removing the low virulent ISAV from the brood fish and that ISAV-free brood fish salmon are kept in closed containment systems (CCS).


Assuntos
Doenças dos Peixes , Pesqueiros , Isavirus , Infecções por Orthomyxoviridae , Salmo salar/virologia , Animais , Doenças dos Peixes/genética , Doenças dos Peixes/transmissão , Doenças dos Peixes/virologia , Hemaglutininas Virais/genética , Isavirus/genética , Isavirus/patogenicidade , Infecções por Orthomyxoviridae/genética , Infecções por Orthomyxoviridae/transmissão , Filogenia , Proteínas Virais de Fusão/genética , Proteínas Virais/genética , Fatores de Virulência/genética
14.
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
15.
Zoonoses Public Health ; 66(4): 401-405, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30843347

RESUMO

Since 2011, there have been 468 cases of variant influenza A virus (IAV) reported in the United States, many of which were associated with youth swine exhibition. In an effort to mitigate risk associated with exposure to IAV in swine, the "Measures to Minimize Influenza Transmission at Swine Exhibitions" (MtM) was developed for show organizers, volunteers and exhibitors. These recommendations are updated annually; however, it is not clear if youth swine exhibitors are aware of the recommendations; support the recommendations; and would be willing to practise recommended behaviours. Therefore, a cross-sectional survey method was used to assess swine exhibitor perceptions and their adoption of swine production practices aimed at reducing the transmission of IAV at the human-animal interface. In addition, the survey asked participants their state of residence and the number of shows they would attend in 2017. In all, 155 participants who showed swine on a regular basis (x̅ = 11 shows per year), from at least 18 states within the US, completed the survey. At least, 67% of participants believed each statement was a good recommendation, with 6 of 11 recommendations being supported by >90% of participants. When asked if recommendations could be implemented, 65%-94% of respondents agreed, and 21%-89% of participants had already implemented each recommendation, respectively. Although significant efforts have been made to increase signage at swine exhibitions (warning of risks associated with eating/drinking in animal areas), a majority of respondents report eating/drinking in the barn and are unwilling to change their behaviours. This study provides evidence that developing and disseminating static recommendations to reduce zoonotic disease transmission is not enough to change human behaviour to prevent future variant IAV infections associated with swine exhibitions.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Influenza Humana/prevenção & controle , Infecções por Orthomyxoviridae/prevenção & controle , Doenças dos Suínos/prevenção & controle , Zoonoses/prevenção & controle , Animais , Estudos Transversais , Exposições como Assunto , Humanos , Vírus da Influenza A , Influenza Humana/transmissão , Infecções por Orthomyxoviridae/transmissão , Saúde Pública , Suínos/virologia , Doenças dos Suínos/virologia , Estados Unidos , Zoonoses/transmissão
16.
J Infect Dis ; 219(Suppl_1): S57-S61, 2019 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-30715379

RESUMO

There is currently an unmet need to develop an effective broadly reactive or universal vaccine against influenza viruses capable of conferring protection against both seasonal and prepandemic strains. Influenza vaccines elicit immune responses that are protective against antigenically similar viruses within a subtype. These vaccines elicit antibodies that target the surface viral glycoproteins hemagglutinin and neuraminidase. If there is an antigenic mismatch between these proteins in the influenza vaccines and cocirculating influenza isolates, there is a decrease in the vaccine effectiveness in vaccinated persons. Various novel influenza vaccine candidates are being evaluated in animal studies and clinical human trials. This article focuses on the advantages and potential shortcomings of broadly reactive or universal vaccine candidates based on the hemagglutinin globular head and the thoughts about using this antigen as the basis for future influenza vaccine strategies.


Assuntos
Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Pandemias/prevenção & controle , Adolescente , Adulto , Idoso , Animais , Antígenos Virais/genética , Anticorpos Amplamente Neutralizantes/imunologia , Deriva Genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Humanos , Memória Imunológica , Lactente , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/epidemiologia , Pessoa de Meia-Idade , Neuraminidase/genética , Neuraminidase/imunologia , Infecções por Orthomyxoviridae/transmissão , Infecções por Orthomyxoviridae/virologia , Suínos/virologia , Vacinação , Adulto Jovem
17.
Artigo em Inglês | MEDLINE | ID: mdl-30791478

RESUMO

Background: The importance of aerosols in the spread of viruses like influenza is still a subject of debate. Indeed, most viruses can also be transmitted through direct contact and droplets. Therefore, the importance of the airborne route in a clinical context is difficult to determine. The aim of this study was to design a chamber system to study the airborne transmission of viruses between ferrets. Methods: A system composed of three chambers connected in series, each one housing one ferret and preventing direct contact, was designed. The chambers were designed to house the ferrets for several days and to study the transmission of viruses from an infected (index) ferret to two naïve ferrets via aerosols and droplets or aerosols only. A particle separator was designed that can be used to modulate the size of the particles traveling between the chambers. The chamber system was validated using standard dust as well as with ferrets infected with influenza A virus. Conclusions: The 50% efficiency cut-off of the separator could be modulated between a 5-µm and an 8-µm aerodynamic diameter. In the described setup, influenza A virus was transmitted through the aerosol route in two out of three experiments, and through aerosols and droplets in all three experiments.


Assuntos
Aerossóis , Vírus da Influenza A/patogenicidade , Infecções por Orthomyxoviridae/transmissão , Animais , Modelos Animais de Doenças , Furões , Humanos , Influenza Humana/virologia , Infecções por Orthomyxoviridae/virologia
18.
Zoonoses Public Health ; 66(2): 232-247, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30680936

RESUMO

Influenza viruses are frequently transmitted between pigs and their handlers, and among pig handlers. However, reports on socio-environmental variables as potential risk factors associated with transmission of influenza in West African swine production facilities are very scarce. Syndromic survey for influenza was therefore conducted in Ibadan, Nigeria, and Kumasi, Ghana, in order to identify and elucidate selected socio-environmental variables that may contribute to the occurrence and distribution of influenza-like illness (ILI) among swine industry workers. In addition, molecular analyses were conducted to elucidate the nature of influenza viruses circulating at the human-swine interface in these cities and better understand the dynamics of their transmission. Influenza viruses were detected by type-specific and subtype-specific RT-PCR. Sequencing and phylogenetic analyses were carried out. Socio-environmental variables were tested by both univariable and multivariable regression methods for significance at p < 0.05. Three risk factors for ILI were identified in each city. These included "frequency of visit of pig handler to pig pen or lairage" (Ibadan: risk ratio [RR] = 1.54, 95% confidence interval [CI] = 1.36-1.79, p = 0.02; Kumasi: RR = 1.28, 95% CI = 1.11-1.71, p = 0.01) and "pig handler's awareness about biosecurity measures" (Ibadan: RR = 7.09, 95% CI = 2.36-21.32, p < 0.001; Kumasi: RR = 4.84, 95% CI = 1.98-11.80, p < 0.001). Influenza A(H1N1)pdm09 viruses, with M genes closely related to those which circulated among pigs in the two cities during the same period, were detected among Nigerian and Ghanaian pig industry workers. These findings suggest the possibility of bidirectional transmission of influenza at the human-swine interface in these cities and underscore the need for more extensive molecular studies. Risk factors identified may assist in the control of human-to-human and human-to-swine transmission of influenza in the West African swine industry.


Assuntos
Influenza Humana/transmissão , Infecções por Orthomyxoviridae/veterinária , Orthomyxoviridae/genética , Doenças dos Suínos/transmissão , Zoonoses/transmissão , Animais , Anticorpos Antivirais/sangue , Cidades/epidemiologia , Feminino , Gana/epidemiologia , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H3N2/genética , Influenza Humana/epidemiologia , Influenza Humana/virologia , Masculino , Nigéria/epidemiologia , Infecções por Orthomyxoviridae/epidemiologia , Infecções por Orthomyxoviridae/transmissão , Filogenia , Reação em Cadeia da Polimerase , Fatores de Risco , Suínos , Doenças dos Suínos/virologia , Zoonoses/epidemiologia , Zoonoses/virologia
19.
J Fish Dis ; 42(1): 3-9, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30468255

RESUMO

Recent outbreaks of a novel tilapia lake virus (TiLV) have raised concerns regarding the international spread of TiLV in frozen tilapia products. This study investigated the potential risks of frozen tilapia fillet as a source of TiLV transmission. It revealed that TiLV genomic RNA could be detected in tilapia fillet and the virus isolated from non-frozen and frozen fillets with clinical TiLV infection stored up to 28 days caused a cytopathic effect (CPE) formation in the susceptible cell line in vitro. However, frozen fillets from clinical TiLV infection stored for 90 and 120 days did not cause CPE in the susceptible cell line. Similarly, CPE was not observed in TiLV isolated from subclinically TiLV-infected fish fillets. In addition, in vivo bioassay revealed that despite the presence of TiLV isolated from subclinically TiLV-infected fillet stored at -20°C for 14 days, there was no evidence of TiLV disease in naïve red hybrid tilapia based on the absence of clinical signs and mortality and without the detection of TiLV genomic RNA using reverse transcription-quantitative polymerase chain reaction assay. Collectively, these findings suggested minimal risk of transmission of TiLV via frozen tilapia fillets.


Assuntos
Doenças dos Peixes/virologia , Alimentos Congelados/virologia , Infecções por Orthomyxoviridae/veterinária , Orthomyxoviridae , Tilápia/virologia , Animais , Linhagem Celular , Doenças dos Peixes/transmissão , Conservação de Alimentos/métodos , Infecções por Orthomyxoviridae/transmissão , RNA Viral/análise
20.
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 , Chlorocebus aethiops , 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
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