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Viruses, Volume 5, Issue 9 (September 2013) – 16 articles , Pages 2062-2328

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73 KiB  
Short Communication
Increased Detection of Sin Nombre Hantavirus RNA in Antibody-Positive Deer Mice from Montana, USA: Evidence of Male Bias in RNA Viremia
by Karoun H. Bagamian, Jonathan S. Towner, James N. Mills and Amy J. Kuenzi
Viruses 2013, 5(9), 2320-2328; https://doi.org/10.3390/v5092320 - 24 Sep 2013
Cited by 12 | Viewed by 5978
Abstract
Hantaviruses are widespread emergent zoonotic agents that cause unapparent or limited disease in their rodent hosts, yet cause acute, often fatal pulmonary or renal infections in humans. Previous laboratory experiments with rodent reservoir hosts indicate that hantaviruses can be cleared from host blood [...] Read more.
Hantaviruses are widespread emergent zoonotic agents that cause unapparent or limited disease in their rodent hosts, yet cause acute, often fatal pulmonary or renal infections in humans. Previous laboratory experiments with rodent reservoir hosts indicate that hantaviruses can be cleared from host blood early in the infection cycle, while sequestered long term in various host organs. Field studies of North American deer mice (Peromyscus maniculatus), the natural reservoir of Sin Nombre hantavirus, have shown that viral RNA can be transiently detected well past the early acute infection stage, but only in the minority of infected mice. Here, using a non-degenerate RT-PCR assay optimized for SNV strains known to circulate in Montana, USA, we show that viral RNA can be repeatedly detected on a monthly basis in up to 75% of antibody positive deer mice for periods up to 3–6 months. More importantly, our data show that antibody positive male deer mice are more than twice as likely to have detectable SNV RNA in their blood as antibody positive females, suggesting that SNV-infected male deer mice are more likely to shed virus and for longer periods of time. Full article
(This article belongs to the Special Issue Hantaviruses)
341 KiB  
Article
Genome Sequencing of West Nile Virus from Human Cases in Greece, 2012
by Luisa Barzon, Anna Papa, Monia Pacenti, Elisa Franchin, Enrico Lavezzo, Laura Squarzon, Giulia Masi, Thomas Martello, Theodolinta Testa, Riccardo Cusinato and Giorgio Palù
Viruses 2013, 5(9), 2311-2319; https://doi.org/10.3390/v5092311 - 24 Sep 2013
Cited by 27 | Viewed by 6918
Abstract
A West Nile Virus (WNV) lineage 2 strain, named Nea Santa-Greece-2010, has been demonstrated to be responsible for the large outbreaks of neuroinvasive disease (WNND) that have been occurring in Greece since 2010, based on sequence similarities of viral isolates identified between 2010–2012. [...] Read more.
A West Nile Virus (WNV) lineage 2 strain, named Nea Santa-Greece-2010, has been demonstrated to be responsible for the large outbreaks of neuroinvasive disease (WNND) that have been occurring in Greece since 2010, based on sequence similarities of viral isolates identified between 2010–2012. However, knowledge on the evolution of this strain is scarce because only partial WNV genome sequences are available from Greece. The aim of this study was to get the complete genome sequence of WNV from patients with infection. To this aim, plasma and urine samples collected during the 2012 Greek outbreak were retrospectively investigated. Full WNV genome sequence was obtained from a patient with WNND. The genome had 99.7% sequence identity to Nea Santa, higher than to other related WNV lineage 2 strains, and five amino acid changes apparently not relevant for viral pathogenicity or fitness. In addition, infection by WNV lineage 2 was confirmed in additional nine patients with WNND; in three of them the infection with WNV Nea Santa was demonstrated by sequencing. In conclusion, this study characterized for the first time a WNV full genome from a patient with WNND from Greece, demonstrated the persistence of the Nea Santa strain, and suggested that the virus might have locally evolved. Full article
(This article belongs to the Section Animal Viruses)
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Review
Role of Natural Killer and Gamma-Delta T cells in West Nile Virus Infection
by Tian Wang and Thomas Welte
Viruses 2013, 5(9), 2298-2310; https://doi.org/10.3390/v5092298 - 20 Sep 2013
Cited by 27 | Viewed by 7377
Abstract
Natural Killer (NK) cells and Gamma-delta T cells are both innate lymphocytes that respond rapidly and non-specifically to viral infection and other pathogens. They are also known to form a unique link between innate and adaptive immunity. Although they have similar immune features [...] Read more.
Natural Killer (NK) cells and Gamma-delta T cells are both innate lymphocytes that respond rapidly and non-specifically to viral infection and other pathogens. They are also known to form a unique link between innate and adaptive immunity. Although they have similar immune features and effector functions, accumulating evidence in mice and humans suggest these two cell types have distinct roles in the control of infection by West Nile virus (WNV), a re-emerging pathogen that has caused fatal encephalitis in North America over the past decade. This review will discuss recent studies on these two cell types in protective immunity and viral pathogenesis during WNV infection. Full article
(This article belongs to the Special Issue West Nile Virus)
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Article
Chronic Bee Paralysis Virus and Nosema ceranae Experimental Co-Infection of Winter Honey Bee Workers (Apis mellifera L.)
by Ivan Toplak, Urška Jamnikar Ciglenečki, Katherine Aronstein and Aleš Gregorc
Viruses 2013, 5(9), 2282-2297; https://doi.org/10.3390/v5092282 - 19 Sep 2013
Cited by 41 | Viewed by 8904
Abstract
Chronic bee paralysis virus (CBPV) is an important viral disease of adult bees which induces significant losses in honey bee colonies. Despite comprehensive research, only limited data is available from experimental infection for this virus. In the present study winter worker bees were [...] Read more.
Chronic bee paralysis virus (CBPV) is an important viral disease of adult bees which induces significant losses in honey bee colonies. Despite comprehensive research, only limited data is available from experimental infection for this virus. In the present study winter worker bees were experimentally infected in three different experiments. Bees were first inoculated per os (p/o) or per cuticle (p/c) with CBPV field strain M92/2010 in order to evaluate the virus replication in individual bees. In addition, potential synergistic effects of co-infection with CBPV and Nosema ceranae (N. ceranae) on bees were investigated. In total 558 individual bees were inoculated in small cages and data were analyzed using quantitative real time RT-PCR (RT-qPCR). Our results revealed successful replication of CBPV after p/o inoculation, while it was less effective when bees were inoculated p/c. Dead bees harbored about 1,000 times higher copy numbers of the virus than live bees. Co-infection of workers with CBPV and N. ceranae using either method of virus inoculation (p/c or p/o) showed increased replication ability for CBPV. In the third experiment the effect of inoculation on bee mortality was evaluated. The highest level of bee mortality was observed in a group of bees inoculated with CBPV p/o, followed by a group of workers simultaneously inoculated with CBPV and N. ceranae p/o, followed by the group inoculated with CBPV p/c and the group with only N. ceranae p/o. The experimental infection with CBPV showed important differences after p/o or p/c inoculation in winter bees, while simultaneous infection with CBPV and N. ceranae suggesting a synergistic effect after inoculation. Full article
(This article belongs to the Section Animal Viruses)
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Article
Development of a One-Step SYBR Green I Real-Time RT-PCR Assay for the Detection and Quantitation of Araraquara and Rio Mamore Hantavirus
by Alex Martins Machado, William Marciel De Souza, Michelly De Pádua, Aline Rafaela Da Silva Rodrigues Machado and Luiz Tadeu Moraes Figueiredo
Viruses 2013, 5(9), 2272-2281; https://doi.org/10.3390/v5092272 - 19 Sep 2013
Cited by 15 | Viewed by 9072
Abstract
Hantaviruses are members of the family Bunyaviridaeandare an emergingcause of diseaseworldwidewithhighlethalityin the Americas. In Brazil, thediagnosis forhantaviruses is basedonimmunologictechniquesassociatedwithconventionalRT-PCR.Anovelone-stepSYBRGreenreal-timeRT-PCRwasdevelopedfor the detectionandquantitationofAraraquarahantavirus(ARAV)and Rio Mamore hantavirus (RIOMV). Thedetectionlimitof assay was 10copies/µLofRNA in vitro transcribed of segment S. The specificity of assay was evaluatedbymeltingcurveanalysis, which [...] Read more.
Hantaviruses are members of the family Bunyaviridaeandare an emergingcause of diseaseworldwidewithhighlethalityin the Americas. In Brazil, thediagnosis forhantaviruses is basedonimmunologictechniquesassociatedwithconventionalRT-PCR.Anovelone-stepSYBRGreenreal-timeRT-PCRwasdevelopedfor the detectionandquantitationofAraraquarahantavirus(ARAV)and Rio Mamore hantavirus (RIOMV). Thedetectionlimitof assay was 10copies/µLofRNA in vitro transcribed of segment S. The specificity of assay was evaluatedbymeltingcurveanalysis, which showed thattheAraraquaravirusamplifiedproductgenerate dameltpeak at80.83±0.89°C without generating primer-dimersornon-specificproducts.The assay was more sensitive than conventional RT-PCR and we detected two samples undetected by conventional RT-PCR. The one-step SYBR Green real-time quantitative RT-PCR is specific, sensible and reproducible, which makes it a powerful tool in both diagnostic applications and general research of ARAVand RIOMVand possibly other Brazilian hantaviruses. Full article
(This article belongs to the Special Issue Hantaviruses)
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Brief Report
Respiratory Syncytial Virus Infection Disrupts Monolayer Integrity and Function in Cystic Fibrosis Airway Cells
by Michele Kong, Patrick Maeng, Jeong Hong, Rhonda Szczesniak, Eric Sorscher, Wayne Sullender and John Paul Clancy
Viruses 2013, 5(9), 2260-2271; https://doi.org/10.3390/v5092260 - 19 Sep 2013
Cited by 16 | Viewed by 6051
Abstract
Background: Respiratory Syncytial Virus (RSV) infection is a common contributor to pulmonary symptoms in children with cystic fibrosis (CF). Here we examined RSV infection in immortalized bronchial epithelial cells (CFBE41o-) expressing wild-type (wt) or F508del cystic fibrosis transmembrane conductance regulator (CFTR), for [...] Read more.
Background: Respiratory Syncytial Virus (RSV) infection is a common contributor to pulmonary symptoms in children with cystic fibrosis (CF). Here we examined RSV infection in immortalized bronchial epithelial cells (CFBE41o-) expressing wild-type (wt) or F508del cystic fibrosis transmembrane conductance regulator (CFTR), for monolayer integrity and RSV replication. Methods: CFBE41o- monolayers expressing wt or F508del CFTR were grown on permeable supports and inoculated with RSV A2 strain. Control experiments utilized UV-inactivated RSV and heat-killed RSV. Monolayer resistance and RSV production was monitored for up to six days post-infection. Results: Within 24 h, a progressive decrease in monolayer resistance was observed in RSV infected F508del CFBE41o- cells, while the monolayer integrity of RSV infected wt CFTR CFBE41o- cells remained stable. RSV replication was necessary to disrupt F508del CFBE41o- monolayers as UV-irradiated and heat killed RSV had no effect on monolayer integrity, with an earlier and much more pronounced peak in RSV titer noted in F508del relative to wt CFTR-expressing cells. RSV infection of wt CFBE41o- monolayers also resulted in blunting of CFTR response. Conclusions: These findings identify an enhanced sensitivity of CFBE41o- cells expressing F508del CFTR to RSV infection, replication and monolayer disruption independent of the cellular immune response, and provide a novel mechanism by which cystic fibrosis airway epithelia are susceptible to RSV-dependent injury. Full article
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168 KiB  
Article
Seroprevalence of Human Herpesvirus-8 in HIV-1 Infected and Uninfected Individuals in Cameroon
by Christelle Mbondji-Wonje, Viswanath Ragupathy, Sherwin Lee, Owen Wood, Bih Awazi and Indira K. Hewlett
Viruses 2013, 5(9), 2253-2259; https://doi.org/10.3390/v5092253 - 19 Sep 2013
Cited by 9 | Viewed by 5369
Abstract
We evaluated the prevalence of HHV-8 antibodies in 516 plasma samples collected from HIV positive and negative patients from blood banks and urban areas of Cameroon. Among HIV-1 positive samples, HHV-8 seropositivity rate was 61% based on combined reactivity using both ELISA and [...] Read more.
We evaluated the prevalence of HHV-8 antibodies in 516 plasma samples collected from HIV positive and negative patients from blood banks and urban areas of Cameroon. Among HIV-1 positive samples, HHV-8 seropositivity rate was 61% based on combined reactivity using both ELISA and IFA techniques. HIV negative samples showed 62% seropositivity rate for HHV-8 antibodies. Our results indicate a high HHV-8 prevalence rate in both HIV infected and uninfected individuals in Cameroon. Full article
(This article belongs to the Section Animal Viruses)
466 KiB  
Article
HIV-1 Infection of T Cells and Macrophages Are Differentially Modulated by Virion-Associated Hck: A Nef-Dependent Phenomenon
by Alyssa Cornall, Johnson Mak, Alison Greenway and Gilda Tachedjian
Viruses 2013, 5(9), 2235-2252; https://doi.org/10.3390/v5092235 - 18 Sep 2013
Cited by 5 | Viewed by 6330
Abstract
The proline repeat motif (PxxP) of Nef is required for interaction with the SH3 domains of macrophage-specific Src kinase Hck. However, the implication of this interaction for viral replication and infectivity in macrophages and T lymphocytes remains unclear. Experiments in HIV-1 infected macrophages [...] Read more.
The proline repeat motif (PxxP) of Nef is required for interaction with the SH3 domains of macrophage-specific Src kinase Hck. However, the implication of this interaction for viral replication and infectivity in macrophages and T lymphocytes remains unclear. Experiments in HIV-1 infected macrophages confirmed the presence of a Nef:Hck complex which was dependent on the Nef proline repeat motif. The proline repeat motif of Nef also enhanced both HIV-1 infection and replication in macrophages, and was required for incorporation of Hck into viral particles. Unexpectedly, wild-type Hck inhibited infection of macrophages, but Hck was shown to enhance infection of primary T lymphocytes. These results indicate that the interaction between Nef and Hck is important for Nef-dependent modulation of viral infectivity. Hck-dependent enhancement of HIV-1 infection of T cells suggests that Nef-Hck interaction may contribute to the spread of HIV-1 infection from macrophages to T cells by modulating events in the producer cell, virion and target cell. Full article
(This article belongs to the Section Animal Viruses)
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718 KiB  
Review
Regulated Transport into the Nucleus of Herpesviridae DNA Replication Core Proteins
by Gualtiero Alvisi, David A. Jans, Daria Camozzi, Simone Avanzi, Arianna Loregian, Alessandro Ripalti and Giorgio Palù
Viruses 2013, 5(9), 2210-2234; https://doi.org/10.3390/v5092210 - 16 Sep 2013
Cited by 15 | Viewed by 8805
Abstract
The Herpesvirdae family comprises several major human pathogens belonging to three distinct subfamilies. Their double stranded DNA genome is replicated in the nuclei of infected cells by a number of host and viral products. Among the latter the viral replication complex, whose activity [...] Read more.
The Herpesvirdae family comprises several major human pathogens belonging to three distinct subfamilies. Their double stranded DNA genome is replicated in the nuclei of infected cells by a number of host and viral products. Among the latter the viral replication complex, whose activity is strictly required for viral replication, is composed of six different polypeptides, including a two-subunit DNA polymerase holoenzyme, a trimeric primase/helicase complex and a single stranded DNA binding protein. The study of herpesviral DNA replication machinery is extremely important, both because it provides an excellent model to understand processes related to eukaryotic DNA replication and it has important implications for the development of highly needed antiviral agents. Even though all known herpesviruses utilize very similar mechanisms for amplification of their genomes, the nuclear import of the replication complex components appears to be a heterogeneous and highly regulated process to ensure the correct spatiotemporal localization of each protein. The nuclear transport process of these enzymes is controlled by three mechanisms, typifying the main processes through which protein nuclear import is generally regulated in eukaryotic cells. These include cargo post-translational modification-based recognition by the intracellular transporters, piggy-back events allowing coordinated nuclear import of multimeric holoenzymes, and chaperone-assisted nuclear import of specific subunits. In this review we summarize these mechanisms and discuss potential implications for the development of antiviral compounds aimed at inhibiting the Herpesvirus life cycle by targeting nuclear import of the Herpesvirus DNA replicating enzymes. Full article
(This article belongs to the Special Issue Viral Nuclear Import)
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38407 KiB  
Review
Non-Simian Foamy Viruses: Molecular Virology, Tropism and Prevalence and Zoonotic/Interspecies Transmission
by Timo Kehl, Juan Tan and Magdalena Materniak
Viruses 2013, 5(9), 2169-2209; https://doi.org/10.3390/v5092169 - 13 Sep 2013
Cited by 42 | Viewed by 10009
Abstract
Within the field of retrovirus, our knowledge of foamy viruses (FV) is still limited. Their unique replication strategy and mechanism of viral persistency needs further research to gain understanding of the virus-host interactions, especially in the light of the recent findings suggesting their [...] Read more.
Within the field of retrovirus, our knowledge of foamy viruses (FV) is still limited. Their unique replication strategy and mechanism of viral persistency needs further research to gain understanding of the virus-host interactions, especially in the light of the recent findings suggesting their ancient origin and long co-evolution with their nonhuman hosts. Unquestionably, the most studied member is the primate/prototype foamy virus (PFV) which was originally isolated from a human (designated as human foamy virus, HFV), but later identified as chimpanzee origin; phylogenetic analysis clearly places it among other Old World primates. Additionally, the study of non-simian animal FVs can contribute to a deeper understanding of FV-host interactions and development of other animal models. The review aims at highlighting areas of special interest regarding the structure, biology, virus-host interactions and interspecies transmission potential of primate as well as non-primate foamy viruses for gaining new insights into FV biology. Full article
(This article belongs to the Special Issue Recent Progress in Foamy Virus (FV) Research)
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Article
Stability and Fitness Impact of the Visually Discernible Rosea1 Marker in the Tobacco etch virus Genome
by Eszter Majer, José-Antonio Daròs and Mark P. Zwart
Viruses 2013, 5(9), 2153-2168; https://doi.org/10.3390/v5092153 - 09 Sep 2013
Cited by 14 | Viewed by 6865
Abstract
Antirrhinum majus Rosea1 (Ros1) is an MYB-related transcription factor that induces anthocyanin biosynthesis in plant tissues, and has been shown to be suitable for visual tracking of virus infection in plants. However, activation of anthocyanin biosynthesis has far reaching effects on plant physiology [...] Read more.
Antirrhinum majus Rosea1 (Ros1) is an MYB-related transcription factor that induces anthocyanin biosynthesis in plant tissues, and has been shown to be suitable for visual tracking of virus infection in plants. However, activation of anthocyanin biosynthesis has far reaching effects on plant physiology and could consequently have negative effects on viral replication. Therefore, viruses carrying the Ros1 marker might have a low fitness and consequently rapidly lose the marker. To compare the stability of the Ros1 marker, we generated Tobacco etch virus (TEV) based constructs containing either Ros1 or the enhanced green fluorescent protein (eGFP) between the NIb and CP cistrons (TEV-Ros1 and TEV-eGFP, respectively). We measured the within-host competitive fitness of both viruses by direct competitions with a common competitor during infection of Nicotiana tabacum. The fitness of TEV-Ros1 was significantly lower than that of TEV-eGFP, and both recombinant viruses had a significantly lower fitness than the wild-type virus. Nevertheless, after seven weeks of infection in N. tabacum, similar levels of marker gene instability where found for both viruses. Despite lower fitness of the marked virus, Ros1 is therefore a viable alternative marker for tracking viral infection in plants. Full article
(This article belongs to the Special Issue Plant Viruses)
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Article
Movements of Wild Ruddy Shelducks in the Central Asian Flyway and Their Spatial Relationship to Outbreaks of Highly Pathogenic Avian Influenza H5N1
by John Y. Takekawa, Diann J. Prosser, Bridget M. Collins, David C. Douglas, William M. Perry, Baoping Yan, Luo Ze, Yuansheng Hou, Fumin Lei, Tianxian Li, Yongdong Li and Scott H. Newman
Viruses 2013, 5(9), 2129-2152; https://doi.org/10.3390/v5092129 - 09 Sep 2013
Cited by 25 | Viewed by 8598
Abstract
Highly pathogenic avian influenza H5N1 remains a serious concern for both poultry and human health. Wild waterfowl are considered to be the reservoir for low pathogenic avian influenza viruses; however, relatively little is known about their movement ecology in regions where HPAI H5N1 [...] Read more.
Highly pathogenic avian influenza H5N1 remains a serious concern for both poultry and human health. Wild waterfowl are considered to be the reservoir for low pathogenic avian influenza viruses; however, relatively little is known about their movement ecology in regions where HPAI H5N1 outbreaks regularly occur. We studied movements of the ruddy shelduck (Tadorna ferruginea), a wild migratory waterfowl species that was infected in the 2005 Qinghai Lake outbreak. We defined their migration with Brownian Bridge utilization distribution models and their breeding and wintering grounds with fixed kernel home ranges. We correlated their movements with HPAI H5N1 outbreaks, poultry density, land cover, and latitude in the Central Asian Flyway. Our Akaike Information Criterion analysis indicated that outbreaks were correlated with land cover, latitude, and poultry density. Although shelduck movements were included in the top two models, they were not a top parameter selected in AICc stepwise regression results. However, timing of outbreaks suggested that outbreaks in the flyway began during the winter in poultry with spillover to wild birds during the spring migration. Thus, studies of the movement ecology of wild birds in areas with persistent HPAI H5N1 outbreaks may contribute to understanding their role in transmission of this disease. Full article
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Article
A Naturally Occurring Defective DNA Satellite Associated with a Monopartite Begomovirus: Evidence for Recombination between Alphasatellite and Betasatellite
by Changjun Huang, Yan Xie, Liling Zhao, He Ren and Zhenghe Li
Viruses 2013, 5(9), 2116-2128; https://doi.org/10.3390/v5092116 - 06 Sep 2013
Cited by 19 | Viewed by 6983
Abstract
Monopartite begomoviruses and their associated satellites form unique disease complexes that have emerged as a serious threat to agriculture worldwide. It is well known that frequent recombination contributes to the diversification and evolution of geminiviruses. In this study, we identified a novel defective [...] Read more.
Monopartite begomoviruses and their associated satellites form unique disease complexes that have emerged as a serious threat to agriculture worldwide. It is well known that frequent recombination contributes to the diversification and evolution of geminiviruses. In this study, we identified a novel defective satellite molecule (RecSat) in association with Tobacco leaf curl Yunnan virus (TbLCYNV) in a naturally infected tobacco plant. Sequence analysis showed that Recsat comprises 754 nucleotides in size and is a chimera involving alphasatellite and betasatellite sequences, containing both betasatellite-conserved region and alphasatellite stem-loop structure. Recombination analysis revealed that RecSat has arisen from three independent recombination events likely involving Tomato yellow leaf curl China betasatellite, Ageratum yellow vein China betasatellite and Tobacco curly shoot alphasatellite. Co-inoculation of RecSat with TbLCYNV induced symptoms indistinguishable from those induced by TbLCYNV alone in Nicotiana benthamiana. Southern blot hybridization showed that RecSat could be trans-replicated stably in N. benthamiana plants by TbLCYNV, and impaired the accumulation of helper virus and co-inoculated alphasatellite. Our results provide the first evidence for recombination between two distinct types of satellites among geminivirus complex and highlight recombination as a driving force for geminivirus evolution. Full article
(This article belongs to the Special Issue Plant Viruses)
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Review
Varicella Zoster Virus (VZV)-Human Neuron Interaction
by Nicholas L. Baird, Xiaoli Yu, Randall J. Cohrs and Don Gilden
Viruses 2013, 5(9), 2106-2115; https://doi.org/10.3390/v5092106 - 04 Sep 2013
Cited by 20 | Viewed by 10073
Abstract
Varicella zoster virus (VZV) is a highly neurotropic, exclusively human herpesvirus. Primary infection causes varicella (chickenpox), wherein VZV replicates in multiple organs, particularly the skin. Widespread infection in vivo is confirmed by the ability of VZV to kill tissue culture cells in vitro [...] Read more.
Varicella zoster virus (VZV) is a highly neurotropic, exclusively human herpesvirus. Primary infection causes varicella (chickenpox), wherein VZV replicates in multiple organs, particularly the skin. Widespread infection in vivo is confirmed by the ability of VZV to kill tissue culture cells in vitro derived from any organ. After varicella, VZV becomes latent in ganglionic neurons along the entire neuraxis. During latency, virus DNA replication stops, transcription is restricted, and no progeny virions are produced, indicating a unique virus-cell (neuron) relationship. VZV reactivation produces zoster (shingles), often complicated by serious neurological and ocular disorders. The molecular trigger(s) for reactivation, and thus the identity of a potential target to prevent it, remains unknown due to an incomplete understanding of the VZV-neuron interaction. While no in vitro system has yet recapitulated the findings in latently infected ganglia, recent studies show that VZV infection of human neurons in SCID mice and of human stem cells, including induced human pluripotent stem cells and normal human neural progenitor tissue-like assemblies, can be established in the absence of a cytopathic effect. Usefulness of these systems in discovering the mechanisms underlying reactivation awaits analyses of VZV-infected, highly pure (>90%), terminally differentiated human neurons capable of prolonged survival in vitro. Full article
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Review
Ecology of West Nile Virus in North America
by William K. Reisen
Viruses 2013, 5(9), 2079-2105; https://doi.org/10.3390/v5092079 - 04 Sep 2013
Cited by 109 | Viewed by 24056
Abstract
The introduction, dispersal and establishment of West Nile virus in North America were reviewed, focusing on factors that may have enhanced receptivity and enabled the invasion process. The overwintering persistence of this tropical virus within temperate latitudes was unexpected, but was key in [...] Read more.
The introduction, dispersal and establishment of West Nile virus in North America were reviewed, focusing on factors that may have enhanced receptivity and enabled the invasion process. The overwintering persistence of this tropical virus within temperate latitudes was unexpected, but was key in the transition from invasion to endemic establishment. The cascade of temporal events allowing sporadic amplification to outbreak levels was discussed within a future perspective. Full article
(This article belongs to the Special Issue West Nile Virus)
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Review
Recombinant Salmonella enterica Serovar Typhimurium as a Vaccine Vector for HIV-1 Gag
by Nyasha Chin'ombe
Viruses 2013, 5(9), 2062-2078; https://doi.org/10.3390/v5092062 - 28 Aug 2013
Cited by 13 | Viewed by 6203
Abstract
The HIV/AIDS epidemic remains a global health problem, especially in Sub-Saharan Africa. An effective HIV-1 vaccine is therefore badly required to mitigate this ever-expanding problem. Since HIV-1 infects its host through the mucosal surface, a vaccine for the virus needs to trigger mucosal [...] Read more.
The HIV/AIDS epidemic remains a global health problem, especially in Sub-Saharan Africa. An effective HIV-1 vaccine is therefore badly required to mitigate this ever-expanding problem. Since HIV-1 infects its host through the mucosal surface, a vaccine for the virus needs to trigger mucosal as well as systemic immune responses. Oral, attenuated recombinant Salmonella vaccines offer this potential of delivering HIV-1 antigens to both the mucosal and systemic compartments of the immune system. So far, a number of pre-clinical studies have been performed, in which HIV-1 Gag, a highly conserved viral antigen possessing both T- and B-cell epitopes, was successfully delivered by recombinant Salmonella vaccines and, in most cases, induced HIV-specific immune responses. In this review, the potential use of Salmonella enterica serovar Typhimurium as a live vaccine vector for HIV-1 Gag is explored. Full article
(This article belongs to the Special Issue AIDS Vaccine 2014)
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