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1.
J Gen Virol ; 97(8): 1865-1876, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27147296

RESUMO

An effective immune response against hepatitis C virus (HCV) requires the early development of multi-specific class 1 CD8+ and class II CD4+ T-cells together with broad neutralizing antibody responses. We have produced mammalian-cell-derived HCV virus-like particles (VLPs) incorporating core, E1 and E2 of HCV genotype 1a to produce such immune responses. Here we describe the biochemical and morphological characterization of the HCV VLPs and study HCV core-specific T-cell responses to the particles. The E1 and E2 glycoproteins in HCV VLPs formed non-covalent heterodimers and together with core protein assembled into VLPs with a buoyant density of 1.22 to 1.28 g cm-3. The HCV VLPs could be immunoprecipited with anti-ApoE and anti-ApoC. On electron microscopy, the VLPs had a heterogeneous morphology and ranged in size from 40 to 80 nm. The HCV VLPs demonstrated dose-dependent binding to murine-derived dendritic cells and the entry of HCV VLPs into Huh7 cells was blocked by anti-CD81 antibody. Vaccination of BALB/c mice with HCV VLPs purified from iodixanol gradients resulted in the production of neutralizing antibody responses while vaccination of humanized MHC class I transgenic mice resulted in the prodution of HCV core-specific CD8+ T-cell responses. Furthermore, IgG purified from the sera of patients chronically infected with HCV genotypes 1a and 3a blocked the binding and entry of the HCV VLPs into Huh7 cells. These results show that our mammalian-cell-derived HCV VLPs induce humoral and HCV-specific CD8+ T-cell responses and will have important implications for the development of a preventative vaccine for HCV.


Assuntos
Hepacivirus/imunologia , Anticorpos Anti-Hepatite C/sangue , Linfócitos T/imunologia , Vacinas de Partículas Semelhantes a Vírus/imunologia , Animais , Anticorpos Neutralizantes/sangue , Linhagem Celular , Células Cultivadas , Hepacivirus/genética , Hepatócitos/virologia , Humanos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Microscopia Eletrônica , Vacinas de Partículas Semelhantes a Vírus/administração & dosagem , Vacinas de Partículas Semelhantes a Vírus/genética , Vacinas de Partículas Semelhantes a Vírus/isolamento & purificação , Proteínas do Core Viral/genética , Proteínas do Core Viral/imunologia , Proteínas do Core Viral/metabolismo , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia , Proteínas do Envelope Viral/metabolismo , Virossomos/genética , Virossomos/imunologia , Virossomos/metabolismo , Virossomos/ultraestrutura
2.
Prev Vet Med ; 111(1-2): 42-50, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-23602337

RESUMO

Tuberculosis (TB) is endemic in Eurasian wild boar (Sus scrofa) and red deer (Cervus elaphus) in south central Spain, where evidence suggests transmission to domestic cattle. Known risk factors for TB at the interface between livestock and wild ungulate species include density and spatial overlap, particularly around waterholes during summer. We evaluated the effectiveness of selective exclusion measures for reducing direct and indirect interaction between extensive beef cattle and wild ungulates at waterholes as an alternative for the integrated control of TB. We first monitored 6 water points (WP) with infrared-triggered cameras at a TB positive cattle farm to quantify interactions. We then assigned 3 WP to be "cattle-only" and 3 to be "wildlife-only". Cattle-only WP were surrounded with a wildlife-proof fence (2.5 m high) and an original design of cattle-specific gate. Wildlife-only WP were surrounded by a fence that wild ungulates could breach but cattle could not (1.2 m high). Red deer, roe deer (Capreolus capreolus) and wild boar easily jumped or undercrossed this fence. Wildlife-only fences were 100% effective in preventing cattle access to WP and did not impede wildlife use. Many cows learned to operate the cattle-specific gate quickly and others followed and learned from them. Within 2 weeks, around 70% of cows actively entered and exited through the cattle-specific gate. We demonstrate how simple, low-cost fencing strategies can serve as biosecurity measures to substantially reduce direct and indirect contact between cattle and wild ungulates, serving to reduce the potential for TB transmission. Our designs can be used in the context of integral plans to mitigate disease transmission between cattle and wildlife, and have potential for protecting or segregating the use of a variety of resources in different contexts.


Assuntos
Criação de Animais Domésticos/métodos , Bovinos/fisiologia , Cervos/fisiologia , Reservatórios de Doenças/veterinária , Sus scrofa/fisiologia , Tuberculose Bovina/prevenção & controle , Tuberculose Bovina/transmissão , Animais , Reservatórios de Doenças/microbiologia , Atividade Motora , Mycobacterium bovis/fisiologia , Espanha/epidemiologia , Tuberculose Bovina/epidemiologia , Tuberculose Bovina/microbiologia
3.
Epidemiol Infect ; 141(7): 1498-508, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23531427

RESUMO

Wildlife reservoir hosts of bovine tuberculosis (bTB) include Eurasian badgers (Meles meles) and brushtail possum (Trichosurus vulpecula) in the UK and New Zealand, respectively. Similar species warrant further investigation in the northern lower peninsula of Michigan, USA due to the continued presence of bTB on cattle farms. Most research in Michigan, USA has focused on interactions between white-tailed deer (Odocoileus virginianus) and cattle (Bos taurus) for the transmission of the infectious agent of bTB, Mycobacterium bovis, due to high deer densities and feeding practices. However, limited data are available on medium-sized mammals such as Virginia opossum (Didelphis virginiana; hereafter referred to as opossum) and their movements and home range in Michigan near cattle farms. We conducted surveillance of medium-sized mammals on previously depopulated cattle farms for presence of M. bovis infections and equipped opossum with Global Positioning System (GPS) technology to assess potential differences in home range between farms inside and outside the bTB core area that has had cattle test positive for M. bovis. On farms inside the bTB core area, prevalence in opossum was comparable [6%, 95% confidence interval (CI) 2.0-11.0] to prevalence in raccoon (Procyon lotor; 4%, 95% CI 1.0-9.0, P=0.439) whereas only a single opossum tested positive for M. bovis on farms outside the bTB core area. The prevalence in opossum occupying farms that had cattle test positive for M. bovis was higher (6.4%) than for opossum occupying farms that never had cattle test positive for M. bovis (0.9%, P=0.01). Mean size of home range for 50% and 95% estimates were similar by sex (P=0.791) both inside or outside the bTB core area (P=0.218). Although surveillance efforts and home range were not assessed on the same farms, opossum use of farms near structures was apparent as was selection for farms over surrounding forested habitats. The use of farms, stored feed, and structures by opossum, their ability to serve as vectors of M. bovis, and their propensity to ingest contaminated sources of M. bovis requires additional research in Michigan, USA.


Assuntos
Didelphis , Reservatórios de Doenças/veterinária , Mycobacterium bovis , Tuberculose/veterinária , Animais , Bovinos , Feminino , Sistemas de Informação Geográfica , Comportamento de Retorno ao Território Vital , Estimativa de Kaplan-Meier , Modelos Logísticos , Masculino , Michigan/epidemiologia , Mycobacterium bovis/isolamento & purificação , Vigilância da População , Prevalência , Análise Espacial , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Tuberculose/transmissão , Tuberculose Bovina/transmissão
4.
Zoonoses Public Health ; 60(1): 46-57, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23137052

RESUMO

Zoonotic disease surveillance is typically initiated after an animal pathogen has caused disease in humans. Early detection of potentially high-risk pathogens within animal hosts may facilitate medical interventions to cope with an emerging disease. To effectively spillover to a novel host, a pathogen may undergo genetic changes resulting in varying transmission potential in the new host and potentially to humans. Rabies virus (RABV) is one model pathogen to consider for studying the dynamics of emerging infectious diseases under both laboratory and field conditions. The evolutionary history of RABV is characterized by regularly documented spillover infections and a series of notable host shifts. Within this context, enhanced field surveillance to improve detection of spillover infections will require validated techniques to non-invasively differentiate infected from non-infected individuals. In this study, we evaluate the use of infrared thermography to detect thermal changes associated with experimental RABV infection in big brown bats (Eptesicus fuscus) in a captive colony. Our results indicated that 62% of rabid bats had detectable facial temperature decreases (-4.6°C, SD ± 2.5) compared with pre-inoculation baseline values. These data suggest potential utility for discriminating rabid bats in natural field settings. In addition, focusing upon RABV circulating in the United States between 2008 and 2011, we confirmed spillover events of bat RABV among carnivores and identified cross-species transmission events caused by four lineages of RABV associated with insectivorous bats. Additionally, our analysis of RABV glycoprotein sequences identified substitutions in antigenic sites that may affect neutralizing activity associated with monoclonal antibodies proposed for use in human post-exposure prophylaxis. This study provides a glimpse into RABV pathobiology and spillover dynamics among and between bats and a variety of mesocarnivores.


Assuntos
Quirópteros/virologia , Doenças Transmissíveis Emergentes/veterinária , Vírus da Raiva/imunologia , Raiva/veterinária , Substituição de Aminoácidos , Animais , Antígenos Virais/imunologia , Sequência de Bases , Carnívoros/virologia , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/transmissão , Doenças Transmissíveis Emergentes/virologia , Reservatórios de Doenças , Face , Glicoproteínas/genética , Humanos , Filogenia , Profilaxia Pós-Exposição , RNA Viral/química , RNA Viral/genética , Raiva/epidemiologia , Raiva/transmissão , Raiva/virologia , Vírus da Raiva/genética , Vírus da Raiva/patogenicidade , Análise de Sequência de RNA , Temperatura , Termografia/métodos , Termografia/veterinária , Estados Unidos/epidemiologia , Proteínas Virais/genética
5.
J Anim Sci ; 90(11): 4090-7, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22859758

RESUMO

Where cattle (Bos taurus) and free-ranging white-tailed deer (Odocoileus virginianus) coexist, they frequently share space and resources, potentially resulting in damage to stores of livestock feed and risk of interspecies disease transmission. Preventing use of stored feed by deer can be an important objective in farm management, depending on amount of damage experienced and perceived risk of disease transmission. Woven wire fences (2.4 to 3.0 m high) are generally considered to be the most effective means for excluding deer. However, rapidly deployable temporary means of excluding deer could be useful, especially during late winter when deer are most physiologically stressed and motivated to consume feed meant for cattle. Thus, the objective of this study was to evaluate a novel 1.2-m-tall electric fence consisting of 4 strands of bipolar tape (not requiring separate ground wires or animal contact with ground) for excluding deer from artificially established feed piles during late winter 2008 in northwestern Minnesota. To induce deer to pause, investigate the fence, and receive negative stimuli before attempting to jump the fence, the bipolar tape was baited with a viscous fluid attractive to deer. The fence was estimated to be >80% effective at reducing deer presence at feed piles (10 treatment sites and 11 control sites) given the late winter to early spring conditions. Despite the efficacy, using the fence as a primary means of protecting stored feed from deer in areas with known disease transmission risk (e.g., presence of bovine tuberculosis) is not recommended because risk could remain unacceptably high if even low numbers of deer access stored feed. Yet, the fence could be effective as immediate protection of stored feed in winter before a more permanent and effective deterrence strategy, such as woven-wire fencing, could be installed during the subsequent summer. The fence would also be effective for reducing deer depredation of stored feed, as well as gardens, small orchards, or other localized or seasonal resources.


Assuntos
Ração Animal , Criação de Animais Domésticos/métodos , Cervos , Animais , Minnesota , Estações do Ano
6.
J Anim Sci ; 87(5): 1787-93, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19098230

RESUMO

Prion diseases such as bovine spongiform encephalopathy, chronic wasting disease, and scrapie pose serious risks to human and animal health due to a host of disease-specific factors, including the resistance of infectious prions (PrP(Sc)) to natural degradation and to most commercial inactivation procedures. In an attempt to address this concern, a mouse model was used to compare the efficacy of an alkaline hydrolysis process with a simulated continuous-flow rendering treatment for disposal of PrP(Sc)-infected biological material. Female C57/BL6 mice (N = 120) were randomly divided into 4 treatment groups (n = 30), and each mouse was injected intraperitoneally with their designated treatment inoculum. Treatment groups 1 and 2 served as the positive and negative controls, respectively. Group 3 was inoculated with rendered scrapie-positive mouse brain material to investigate the effectiveness of simulated continuous-flow rendering practices to reduce or eliminate PrP(Sc). Group 4 was inoculated with hydrolyzed scrapie-positive mouse brain material to determine the sterilizing effect of alkaline hydrolysis on PrP(Sc). Mice were monitored for overt signs of disease, and those showing clinical signs were killed to prevent undue suffering. Brains were obtained from all mice that died (or were killed) and analyzed with an ELISA for the presence of PrP(Sc). Results indicated that the simulated continuous-flow rendering treatment used for preparing the rendering treatment group inoculum failed to completely eliminate PrP(Sc). Rendering delayed, but did not stop, clinical mouse-adapted scrapie transmission. Compared with positive controls, the rendering treatment group experienced an approximate 45-d average delay in days to death (250 vs. 205 d for positive controls; P < 0.0001) and a death loss of 73.9% (P = 0.0094). Positive controls suffered 100% death loss. The results validated the efficacy of the alkaline hydrolysis treatment to inactivate all PrP(Sc) because no alkaline hydrolysis treatment group mice succumbed to the disease (P < 0.0001). Based on our results, alkaline hydrolysis should be considered by the animal rendering and beef packing industries as an alternative to incineration, landfill burial, and rendering for disposing of biological material potentially infected or contaminated with prion disease.


Assuntos
Criação de Animais Domésticos/métodos , Hidrólise , Eliminação de Resíduos de Serviços de Saúde/métodos , Scrapie/prevenção & controle , Criação de Animais Domésticos/normas , Animais , Modelos Animais de Doenças , Feminino , Hidróxidos/química , Eliminação de Resíduos de Serviços de Saúde/normas , Camundongos , Camundongos Endogâmicos C57BL , Compostos de Potássio/química , Scrapie/mortalidade , Análise de Sobrevida
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