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1

Evidence for Directional Selection at a Novel Major Histocompatibility Class I Marker in Wild Common Frogs (Rana temporaria) Exposed to a Viral Pathogen (Ranavirus)  

PubMed Central

Whilst the Major Histocompatibility Complex (MHC) is well characterized in the anuran Xenopus, this region has not previously been studied in another popular model species, the common frog (Rana temporaria). Nor, to date, have there been any studies of MHC in wild amphibian host-pathogen systems. We characterise an MHC class I locus in the common frog, and present primers to amplify both the whole region, and specifically the antigen binding region. As no more than two expressed haplotypes were found in over 400 clones from 66 individuals, it is likely that there is a single class I locus in this species. This finding is consistent with the single class I locus in Xenopus, but contrasts with the multiple loci identified in axolotls, providing evidence that the diversification of MHC class I into multiple loci likely occurred after the Caudata/Anura divergence (approximately 350 million years ago) but before the Ranidae/Pipidae divergence (approximately 230 mya). We use this locus to compare wild populations of common frogs that have been infected with a viral pathogen (Ranavirus) with those that have no history of infection. We demonstrate that certain MHC supertypes are associated with infection status (even after accounting for shared ancestry), and that the diseased populations have more similar supertype frequencies (lower FST) than the uninfected. These patterns were not seen in a suite of putatively neutral microsatellite loci. We interpret this pattern at the MHC locus to indicate that the disease has imposed selection for particular haplotypes, and hence that common frogs may be adapting to the presence of Ranavirus, which currently kills tens of thousands of amphibians in the UK each year.

Teacher, Amber G. F.; Garner, Trenton W. J.; Nichols, Richard A.

2009-01-01

2

Recent host-shifts in ranaviruses: signatures of positive selection in the viral genome.  

PubMed

Ranaviruses have been implicated in recent declines in global amphibian populations. Compared with the family Iridoviridae, to which the genus Ranavirus belongs, ranaviruses have a wide host range in that species/strains are known to infect fish, amphibians and reptiles, presumably due to recent host-switching events. We used eight sequenced ranavirus genomes and two selection-detection methods (site based and branch based) to identify genes that exhibited signatures of positive selection, potentially due to the selective pressures at play during host switching. We found evidence of positive selection acting on four genes via the site-based method, three of which were newly acquired genes unique to ranavirus genomes. Using the branch-based method, we identified eight additional candidate genes that exhibited signatures of dN/dS (non-synonymous/synonymous substitution rate) >1 in the clade where intense host switching had occurred. We found that these branch-specific patterns of elevated dN/dS were enriched in a small group of viral genes that have been acquired most recently in the ranavirus genome, compared with core genes that are shared among all members of the family Iridoviridae. Our results suggest that the group of newly acquired genes in the ranavirus genome may have undergone recent adaptive changes that have facilitated interspecies and interclass host switching. PMID:23784445

Abrams, A Jeanine; Cannatella, David C; Hillis, David M; Sawyer, Sara L

2013-06-19

3

Leafhopper viral pathogens  

Technology Transfer Automated Retrieval System (TEKTRAN)

Four newly discovered viral pathogens in leafhopper vectors of Pierce’s disease of grapes, have been shown to replicate in sharpshooter leafhoppers; the glassy-winged sharpshooter, GWSS, Homalodisca vitripennis, and Oncometopia nigricans (Hemiptera: Cicadellidae). The viruses were classified as memb...

4

Ecopathology of Ranaviruses Infecting Amphibians  

PubMed Central

Ranaviruses are capable of infecting amphibians from at least 14 families and over 70 individual species. Ranaviruses infect multiple cell types, often culminating in organ necrosis and massive hemorrhaging. Subclinical infections have been documented, although their role in ranavirus persistence and emergence remains unclear. Water is an effective transmission medium for ranaviruses, and survival outside the host may be for significant duration. In aquatic communities, amphibians, reptiles and fish may serve as reservoirs. Controlled studies have shown that susceptibility to ranavirus infection and disease varies among amphibian species and developmental stages, and likely is impacted by host-pathogen coevolution, as well as, exogenous environmental factors. Field studies have demonstrated that the likelihood of epizootics is increased in areas of cattle grazing, where aquatic vegetation is sparse and water quality is poor. Translocation of infected amphibians through commercial trade (e.g., food, fish bait, pet industry) contributes to the spread of ranaviruses. Such introductions may be of particular concern, as several studies report that ranaviruses isolated from ranaculture, aquaculture, and bait facilities have greater virulence (i.e., ability to cause disease) than wild-type isolates. Future investigations should focus on the genetic basis for pathogen virulence and host susceptibility, ecological and anthropogenic mechanisms contributing to emergence, and vaccine development for use in captive populations and species reintroduction programs.

Miller, Debra; Gray, Matthew; Storfer, Andrew

2011-01-01

5

Viral pathogen discovery.  

PubMed

Viral pathogen discovery is of critical importance to clinical microbiology, infectious diseases, and public health. Genomic approaches for pathogen discovery, including consensus polymerase chain reaction (PCR), microarrays, and unbiased next-generation sequencing (NGS), have the capacity to comprehensively identify novel microbes present in clinical samples. Although numerous challenges remain to be addressed, including the bioinformatics analysis and interpretation of large datasets, these technologies have been successful in rapidly identifying emerging outbreak threats, screening vaccines and other biological products for microbial contamination, and discovering novel viruses associated with both acute and chronic illnesses. Downstream studies such as genome assembly, epidemiologic screening, and a culture system or animal model of infection are necessary to establish an association of a candidate pathogen with disease. PMID:23725672

Chiu, Charles Y

2013-05-29

6

Environmental persistence of amphibian and reptilian ranaviruses.  

PubMed

Ranaviruses infect fish, amphibians, and reptiles. The present study was conducted to compare the persistence of amphibian and reptilian ranaviruses in a pond habitat. The 4 viruses used in this study included 2 amphibian ranaviruses, Frog virus 3 (FV3, the type species of the genus Ranavirus) and an isolate from a frog, and 2 ranaviruses of reptilian origin (from a tortoise and from a gecko). A sandwich germ-carrier technique was used to study the persistence of these viruses in sterile and unsterile pond water (PW) and soil obtained from the bank of a pond. For each virus, virus-loaded carriers were placed in each of the 3 substrates, incubated at 4 and 20°C, and titrated at regular intervals. Serial data were analyzed using a linear regression model to calculate T-90 values (time required for 90% reduction in the virus titer). Resistance of the viruses to drying was also studied. All 4 viruses were resistant to drying. At 20°C, T-90 values of the viruses were 22 to 31 d in sterile PW and 22 to 34 d in unsterile PW. Inactivation of all 4 viruses in soil at this temperature appeared to be non-linear. T-90 values at 4°C were 102 to 182 d in sterile PW, 58 to 72 d in unsterile PW, and 30 to 48 d in soil. Viral persistence was highest in the sterile PW, followed by the unsterile PW, and was lowest in soil. There were no significant differences in the survival times between the amphibian and reptilian viruses. The results of the present study suggest that ranaviruses can survive for long periods of time in pond habitats at low temperatures. PMID:22535867

Nazir, J; Spengler, M; Marschang, R E

2012-04-26

7

Infection and co-infection by the amphibian chytrid fungus and ranavirus in wild Costa Rican frogs.  

PubMed

Amphibian populations are globally threatened by emerging infectious diseases, and 2 pathogens in particular are recognized as major threats: the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) and ranaviruses. Here, we evaluated the prevalence of infection by Bd and ranavirus in an assemblage of frogs from a lowland wet forest in Costa Rica. We found an overall prevalence of 21.3% for Bd and 16.6% for ranavirus, and detected both pathogens widely among our 20 sampled species. We found a positive association between ranavirus and Bd infection in one of our 4 most commonly sampled species. We also found a positive but non-significant association between infection by ranavirus and infection by Bd among species overall. Our study is among the first detailed evaluations of ranavirus prevalence in the American tropics, and to our knowledge is the first to detect a positive association between Bd and ranavirus in any species. Considerable research attention has focused on the ecology of Bd in tropical regions, yet we argue that greater research focus is necessary to understand the ecology and conservation impact of ranaviruses on amphibian populations already decimated by the emergence of Bd. PMID:23709470

Whitfield, Steven M; Geerdes, Erica; Chacon, Iria; Ballestero Rodriguez, Erick; Jimenez, Randall R; Donnelly, Maureen A; Kerby, Jacob L

2013-05-27

8

Animal vaccination and the evolution of viral pathogens  

Microsoft Academic Search

Summary Despite reducing disease, vaccination rarely protects against infection and many pathogens persist within vaccinated animal populations. Circulation of viral pathogens within vaccinated populations may favour the development of vaccine resistance with implications for the evolution of virus pathogenicity and the emergence of variant viruses. The high rate of mutations during replication of ribonucleic acid (RNA) viruses is conducive to

K. A. Schat; E. Baranowski

9

Mass mortality associated with a frog virus 3-like Ranavirus infection in farmed tadpoles Rana catesbeiana from Brazil  

PubMed Central

Ranviruses (Iridoviridae) are increasingly associated with mortality events in amphibians, fish, and reptiles. They have been recently associated with mass mortality events in Brazilian farmed tadpoles of the American bullfrog Rana catesbeiana Shaw. 1802. The objectives of the present study were to further characterize the virus isolated from sick R. catesbeiana tadpoles and confirm the etiology in these outbreaks. Sick tadpoles were collected in 3 farms located in Goiás State, Brazil, from 2003 to 2005 and processed for virus isolation and characterization, microbiology, histopathology, and parasitology. The phylogenetic relationships of Rana catesbeiana ranavirus (RCV-BR) with other genus members was investigated by PCR with primers specific for the major capsid protein gene (MCP) and the RNA polymerase DNA-dependent gene (Pol II). Sequence analysis and multiple alignments for MCP products showed >99% amino acid identity with other ranaviruses, while Pol II products showed 100% identity. Further diagnostics of the pathology including histology and transmission electron microscopy confirmed the viral etiology of these mass deaths. As for as we know, this is the first report of a ranaviral infection affecting aquatic organisms in Brazil. Additionally, our results suggest that American bullfrogs may have served as a vector of transmission of this virus, which highlights the potential threat of amphibian translocation in the world distribution of pathogens.

Mazzoni, Rolando; de Mesquita, Albenones Jose; Fleury, Luiz Fernando F.; de Brito, Wilia Marta Elsner Diederichsen; Nunes, Iolanda A.; Robert, Jacques; Morales, Heidi; Coelho, Alexandre Siqueira Guedes; Barthasson, Denise Leao; Galli, Leonardo; Catroxo, Marcia H. B.

2010-01-01

10

Susceptibility of the European common frog Rana temporaria to a panel of ranavirus isolates from fish and amphibian hosts.  

PubMed

Ranaviruses are an emerging group of viruses and have been implicated in an increase of epidemics in susceptible species. They have a wide host range, infecting fish, amphibians and reptiles, with some isolates able to infect multiple species from different animal classes. Whilst some information exists on the pathogenicity of ranaviruses to novel hosts, there is none on the pathogenicity of fish ranaviruses to amphibians; this information is needed to develop measures to prevent the further spread of ranaviral disease in the aquatic environment. We undertook bath infection trials to assess the susceptibility of the European common frog Rana temporaria to 9 ranavirus isolates comprising doctor fish virus (DFV), European sheatfish virus (ESV), epizootic haematopoietic necrosis virus (EHNV), guppy virus 6 (GV6), pike-perch iridovirus (PPIV) and short-finned eel ranavirus (SERV) from fish hosts, and Bohle iridovirus (BIV), frog virus 3 (FV3) and Rana esculenta virus 282/I02 (REV) from amphibians. Animals were challenged as tadpoles at 15 and 20°C and as recent metamorphs at room temperature (20 ± 1°C) to investigate the effect of temperature and amphibian developmental stage on virus pathogenicity. Tadpoles were susceptible to FV3, PPIV and REV, but refractory to the other ranaviruses. Post-metamorphs were susceptible to FV3 and REV but refractory to BIV (the other ranaviruses were not tested). Significant mortality occurred in post-metamorphs and in tadpoles challenged at 20°C but was low in tadpoles challenged at 15°C. This study presents the first evidence of mortality in an amphibian species after challenge with ranavirus originally isolated from fish. PMID:23574703

Bayley, Amanda E; Hill, Barry J; Feist, Stephen W

2013-04-11

11

Point detection of bacterial and viral pathogens using oral samples  

NASA Astrophysics Data System (ADS)

Oral samples, including saliva, offer an attractive alternative to serum or urine for diagnostic testing. This is particularly true for point-of-use detection systems. The various types of oral samples that have been reported in the literature are presented here along with the wide variety of analytes that have been measured in saliva and other oral samples. The paper focuses on utilizing point-detection of infectious disease agents, and presents work from our group on a rapid test for multiple bacterial and viral pathogens by monitoring a series of targets. It is thus possible in a single oral sample to identify multiple pathogens based on specific antigens, nucleic acids, and host antibodies to those pathogens. The value of such a technology for detecting agents of bioterrorism at remote sites is discussed.

Malamud, Daniel

2008-05-01

12

Infection Strategies of Bacterial and Viral Pathogens through Pathogen-Human Protein-Protein Interactions  

PubMed Central

Since ancient times, even in today’s modern world, infectious diseases cause lots of people to die. Infectious organisms, pathogens, cause diseases by physical interactions with human proteins. A thorough analysis of these interspecies interactions is required to provide insights about infection strategies of pathogens. Here we analyzed the most comprehensive available pathogen–human protein interaction data including 23,435 interactions, targeting 5,210 human proteins. The data were obtained from the newly developed pathogen–host interaction search tool, PHISTO. This is the first comprehensive attempt to get a comparison between bacterial and viral infections. We investigated human proteins that are targeted by bacteria and viruses to provide an overview of common and special infection strategies used by these pathogen types. We observed that in the human protein interaction network the proteins targeted by pathogens have higher connectivity and betweenness centrality values than those proteins not interacting with pathogens. The preference of interacting with hub and bottleneck proteins is found to be a common infection strategy of all types of pathogens to manipulate essential mechanisms in human. Compared to bacteria, viruses tend to interact with human proteins of much higher connectivity and centrality values in the human network. Gene Ontology enrichment analysis of the human proteins targeted by pathogens indicates crucial clues about the infection mechanisms of bacteria and viruses. As the main infection strategy, bacteria interact with human proteins that function in immune response to disrupt human defense mechanisms. Indispensable viral strategy, on the other hand, is the manipulation of human cellular processes in order to use that transcriptional machinery for their own genetic material transcription. A novel observation about pathogen–human systems is that the human proteins targeted by both pathogens are enriched in the regulation of metabolic processes.

Durmus Tekir, Saliha; Cakir, Tunahan; Ulgen, Kutlu O

2012-01-01

13

De novo identification of viral pathogens from cell culture hologenomes  

PubMed Central

Background Fast, specific identification and surveillance of pathogens is the cornerstone of any outbreak response system, especially in the case of emerging infectious diseases and viral epidemics. This process is generally tedious and time-consuming thus making it ineffective in traditional settings. The added complexity in these situations is the non-availability of pure isolates of pathogens as they are present as mixed genomes or hologenomes. Next-generation sequencing approaches offer an attractive solution in this scenario as it provides adequate depth of sequencing at fast and affordable costs, apart from making it possible to decipher complex interactions between genomes at a scale that was not possible before. The widespread application of next-generation sequencing in this field has been limited by the non-availability of an efficient computational pipeline to systematically analyze data to delineate pathogen genomes from mixed population of genomes or hologenomes. Findings We applied next-generation sequencing on a sample containing mixed population of genomes from an epidemic with appropriate processing and enrichment. The data was analyzed using an extensive computational pipeline involving mapping to reference genome sets and de-novo assembly. In depth analysis of the data generated revealed the presence of sequences corresponding to Japanese encephalitis virus. The genome of the virus was also independently de-novo assembled. The presence of the virus was in addition, verified using standard molecular biology techniques. Conclusions Our approach can accurately identify causative pathogens from cell culture hologenome samples containing mixed population of genomes and in principle can be applied to patient hologenome samples without any background information. This methodology could be widely applied to identify and isolate pathogen genomes and understand their genomic variability during outbreaks.

2012-01-01

14

Natural stressors and ranavirus susceptibility in larval wood frogs (Rana sylvatica).  

PubMed

Chronic exposure to stressors has been shown to suppress immune function in vertebrates, making them more susceptible to pathogens. It is less clear, however, whether many natural stressors are immunosuppressive. Moreover, whether stressors make disease more likely or more severe in populations is unclear because animals respond to stressors both behaviorally and physiologically. We tested whether chronic exposure to three natural stressors of wood frog tadpoles-high-densities, predator-cues, and low-food conditions-influence their susceptibility to a lethal ranavirus both individually in laboratory experiments, and collectively in outdoor mesocosms. Prior to virus exposure, we observed elevated corticosterone only in low-food treatments, although other treatments altered rates of growth and development as well as tadpole behavior. None of the treatments, however, increased susceptibility to ranavirus as measured by the proportion of tadpoles that became infected or died, or the time to death compared to controls. In fact, mortality in the mesocosms was actually lower in the high-density treatment even though most individuals became infected, largely because of increased rates of metamorphosis. Overall we find no support for the hypothesis that chronic exposure to common, ecologically relevant challenges necessarily elevates corticosterone levels in a population or leads to more severe ranaviral disease or epidemics. Conditions may, however, conspire to make ranavirus infection more common in metamorphosing amphibians. PMID:23579812

Reeve, Brooke C; Crespi, Erica J; Whipps, Christopher M; Brunner, Jesse L

2013-04-12

15

Population genetic patterns suggest a behavioural change in wild common frogs (Rana temporaria) following disease outbreaks (Ranavirus).  

PubMed

We use 14 microsatellite loci to investigate the impact of a viral disease (Ranavirus) on the population genetic structure of wild common frogs (Rana temporaria). Populations with a history of Ranavirus mortalities (and 83% declines in the number of frogs) were compared with populations with no history of infection. Infected ponds showed significantly elevated F(IS) (homozygote excess), significantly reduced relatedness, and no detectable effect on allelic richness. We hypothesize that the elevated F(IS) and reduced relatedness are consequences of assortative mating, and that allelic richness is maintained by immigration from nearby populations. Simulations indicate that the elevated F(IS) cannot be explained by population size reductions, but can indeed be explained by assortative mating (even if a mate choice locus is unlinked to the genetic markers). While the majority of studies consider demographic outcomes following disease outbreaks, our results indicate that emerging infectious diseases could also result in behavioural changes. PMID:19566676

Teacher, Amber G F; Garner, Trenton W J; Nichols, Richard A

2009-06-29

16

Rapid multiplex PCR assay to identify respiratory viral pathogens: moving forward diagnosing the common cold.  

PubMed

Upper respiratory tract infections (URIs) can be a serious burden to the healthcare system. The majority of URIs are viral in etiology, but definitive diagnosis can prove difficult due to frequently overlapping clinical presentations of viral and bacterial infections, and the variable sensitivity, and lengthy turn-around time of viral culture. We tested new automated nested multiplex PCR technology, the FilmArray(®) system, in the TAMC department of clinical investigations, to determine the feasibility of replacing the standard viral culture with a rapid turn-around system. We conducted a feasibility study using a single-blinded comparison study, comparing PCR results with archived viral culture results from a convenience sample of cryopreserved archived nasopharyngeal swabs from acutely ill ED patients who presented with complaints of URI symptoms. A total of 61 archived samples were processed. Viral culture had previously identified 31 positive specimens from these samples. The automated nested multiplex PCR detected 38 positive samples. In total, PCR was 94.5% concordant with the previously positive viral culture results. However, PCR was only 63.4% concordant with the negative viral culture results, owing to PCR detection of 11 additional viral pathogens not recovered on viral culture. The average time to process a sample was 75 minutes. We determined that an automated nested multiplex PCR is a feasible alternative to viral culture in an acute clinical setting. We were able to detect at least 94.5% as many viral pathogens as viral culture is able to identify, with a faster turn-around time. PMID:24052914

Layman, Clifton P; Gordon, Sarah M; Elegino-Steffens, Diane U; Agee, Willie; Barnhill, Jason; Hsue, Gunther

2013-09-01

17

Rapid Multiplex PCR Assay To Identify Respiratory Viral Pathogens: Moving Forward Diagnosing The Common Cold  

PubMed Central

Upper respiratory tract infections (URIs) can be a serious burden to the healthcare system. The majority of URIs are viral in etiology, but definitive diagnosis can prove difficult due to frequently overlapping clinical presentations of viral and bacterial infections, and the variable sensitivity, and lengthy turn-around time of viral culture. We tested new automated nested multiplex PCR technology, the FilmArray® system, in the TAMC department of clinical investigations, to determine the feasibility of replacing the standard viral culture with a rapid turn-around system. We conducted a feasibility study using a single-blinded comparison study, comparing PCR results with archived viral culture results from a convenience sample of cryopreserved archived nasopharyngeal swabs from acutely ill ED patients who presented with complaints of URI symptoms. A total of 61 archived samples were processed. Viral culture had previously identified 31 positive specimens from these samples. The automated nested multiplex PCR detected 38 positive samples. In total, PCR was 94.5% concordant with the previously positive viral culture results. However, PCR was only 63.4% concordant with the negative viral culture results, owing to PCR detection of 11 additional viral pathogens not recovered on viral culture. The average time to process a sample was 75 minutes. We determined that an automated nested multiplex PCR is a feasible alternative to viral culture in an acute clinical setting. We were able to detect at least 94.5% as many viral pathogens as viral culture is able to identify, with a faster turn-around time.

Gordon, Sarah M; Elegino-Steffens, Diane U; Agee, Willie; Barnhill, Jason; Hsue, Gunther

2013-01-01

18

Presence of Viral Nucleic Acids in the Middle Ear: Acute Otitis Media Pathogen or Bystander?  

PubMed Central

Viruses play an important role in acute otitis media (AOM) pathogenesis and live viruses may cause AOM in absence of pathogenic bacteria. Detection of AOM pathogens generally relies on bacterial culture of middle ear fluid. When viral culture is used and live viruses are detected in the middle ear fluid of children with AOM, the viruses are generally accepted as AOM pathogens. Because viral culture is not sensitive and does not detect the comprehensive spectrum of respiratory viruses, polymerase chain reaction (PCR) assays are commonly used to detect viral nucleic acids in the middle ear fluid. While PCR assays have greatly increased the viral detection rate, new questions arise on the significance of viral nucleic acids detected in the middle ear because nucleic acids of multiple viruses are detected simultaneously, and nucleic acids of specific viruses are detected repeatedly and in a high proportion of asymptomatic children. This article first reviews the role of live viruses in AOM and presents the point-counter point arguments on whether viral nucleic acids in the middle ear represent an AOM pathogen or a bystander status. While there is evidence to support both directions, helpful information for interpretation of the data and future research direction are outlined.

CHONMAITREE, TASNEE; RUOHOLA, AINO; HENDLEY, J. OWEN

2011-01-01

19

Differential host response, rather than early viral replication efficiency, correlates with pathogenicity caused by influenza viruses.  

PubMed

Influenza viruses exhibit large, strain-dependent differences in pathogenicity in mammalian hosts. Although the characteristics of severe disease, including uncontrolled viral replication, infection of the lower airway, and highly inflammatory cytokine responses have been extensively documented, the specific virulence mechanisms that distinguish highly pathogenic strains remain elusive. In this study, we focused on the early events in influenza infection, measuring the growth rate of three strains of varying pathogenicity in the mouse airway epithelium and simultaneously examining the global host transcriptional response over the first 24 hours. Although all strains replicated equally rapidly over the first viral life-cycle, their growth rates in both lung and tracheal tissue strongly diverged at later times, resulting in nearly 10-fold differences in viral load by 24 hours following infection. We identified separate networks of genes in both the lung and tracheal tissues whose rapid up-regulation at early time points by specific strains correlated with a reduced viral replication rate of those strains. The set of early-induced genes in the lung that led to viral growth restriction is enriched for both NF-?B binding site motifs and members of the TREM1 and IL-17 signaling pathways, suggesting that rapid, NF-?B -mediated activation of these pathways may contribute to control of viral replication. Because influenza infection extending into the lung generally results in severe disease, early activation of these pathways may be one factor distinguishing high- and low-pathogenicity strains. PMID:24073225

Askovich, Peter S; Sanders, Catherine J; Rosenberger, Carrie M; Diercks, Alan H; Dash, Pradyot; Navarro, Garnet; Vogel, Peter; Doherty, Peter C; Thomas, Paul G; Aderem, Alan

2013-09-20

20

Differential Host Response, Rather Than Early Viral Replication Efficiency, Correlates with Pathogenicity Caused by Influenza Viruses  

PubMed Central

Influenza viruses exhibit large, strain-dependent differences in pathogenicity in mammalian hosts. Although the characteristics of severe disease, including uncontrolled viral replication, infection of the lower airway, and highly inflammatory cytokine responses have been extensively documented, the specific virulence mechanisms that distinguish highly pathogenic strains remain elusive. In this study, we focused on the early events in influenza infection, measuring the growth rate of three strains of varying pathogenicity in the mouse airway epithelium and simultaneously examining the global host transcriptional response over the first 24 hours. Although all strains replicated equally rapidly over the first viral life-cycle, their growth rates in both lung and tracheal tissue strongly diverged at later times, resulting in nearly 10-fold differences in viral load by 24 hours following infection. We identified separate networks of genes in both the lung and tracheal tissues whose rapid up-regulation at early time points by specific strains correlated with a reduced viral replication rate of those strains. The set of early-induced genes in the lung that led to viral growth restriction is enriched for both NF-?B binding site motifs and members of the TREM1 and IL-17 signaling pathways, suggesting that rapid, NF-?B –mediated activation of these pathways may contribute to control of viral replication. Because influenza infection extending into the lung generally results in severe disease, early activation of these pathways may be one factor distinguishing high- and low-pathogenicity strains.

Askovich, Peter S.; Sanders, Catherine J.; Rosenberger, Carrie M.; Diercks, Alan H.; Dash, Pradyot; Navarro, Garnet; Vogel, Peter; Doherty, Peter C.; Thomas, Paul G.; Aderem, Alan

2013-01-01

21

DEVELOPMENT OF BIOMARKER OF EXPOSURE TO VIRAL PATHOGENS  

EPA Science Inventory

Interferon gamma (IFN-?) was selected as a biomarker for a viral exposure study. Twelve-week-old BALB/c mice were intraperitoneally injected with 0.2ml of 104 PFU/ml of coxsackievirus B3 or B4 diluted in phosphate-buffered saline (PBS). Control mice were injected with PBS on...

22

Waterborne infectivity of the ranavirus Frog-Virus 3 in Xenopus laevis  

PubMed Central

Ranaviruses like Frog Virus 3 (FV3) are responsible of emerging infectious diseases spreading worldwide to fish, amphibian and reptilian species. We have developed, in Xenopus laevis, an experimental model to investigate viral transmission. We show that FV3 released in water by immunocompromised infected adults can infect adult and larval stages of Xenopus within 3 hours of exposure. Time course of virus load and viral transcription in different tissues suggests that early waterborne FV3 infection through the digestive tract leads to dissemination in the kidney. Finally, a fraction of adult macrophages becomes infected following exposure to waterborne FV3 as visualized by fluorescence microscopy using macrophage- and FV3-specific antibodies. Little cytopathicity and apoptosis were detected in infected macrophages, which is consistent with our proposition that macrophages are permissive to FV3. These data highlight the efficiency of FV3 infectivity by the water route and the ability of FV3 to adapt to its hosts.

Robert, Jacques; George, Erica; De Jesus Andino, Francisco; Chen, Guangchun

2011-01-01

23

Enteric viral pathogens in children with inflammatory bowel disease.  

PubMed

The causes of exacerbations of inflammatory bowel disease (IBD) are unknown. The presence of RNA of an enterovirus, norovirus GI, norovirus GII, rotavirus, astrovirus, and sapovirus was sought in stool samples of 50 children (median age 12.9 years) undergoing gastrointestinal endoscopies for IBD or its exclusion (Crohn's disease n?=?18, ulcerative colitis n?=?13, indeterminate colitis n?=?2, non-IBD n?=?17). Viral RNA was found in three fecal samples (norovirus GII n?=?2, sapovirus n?=?1), all in children without IBD. Therefore, enteral viruses may play only a minor role in IBD. PMID:22170557

Kolho, Kaija-Leena; Klemola, Päivi; Simonen-Tikka, Marja-Leena; Ollonen, Marja-Liisa; Roivainen, Merja

2012-02-01

24

Slow coevolution of a viral pathogen and its diploid host.  

PubMed

We study a population exposed to a lethal infectious disease. Host response is carried at one locus with two alleles while the pathogen occurs in two variants. Based on an SI-type epidemic model we derive explicit equations for the dynamics of each genotype. By assuming small variations in both host and disease, we obtain a separation in time scales between epidemic and evolutionary processes. This allows us to describe explicitly the changes in host and disease gene frequencies. The resulting model has a rich behaviour including multiple stable states and oscillations. However, in the oscillatory situation the model is degenerate excluding the possibility of limit cycles. We show that the degeneracy can only be removed by frequency dependent selection in the pathogen, for example by including direct interaction of virus in a free-living stage. The qualitative conclusions extend to an SIR-type epidemic model, where recovery with immunity from the disease is possible. PMID:8577829

Andreasen, V; Christiansen, F B

1995-05-30

25

A review on viral biosensors to detect human pathogens.  

PubMed

Rapid identification of viruses has important implications for medical healthcare. Current methods for identification and quantification of particular virus are time consuming and often expensive. Therefore, demand for sensitive and accurate viral biosensors with rapid detection systems is increasing. A hand held biosensing device would give fast, reliable results for identifying and quantitating the number of virus particles in a sample. Techniques currently being applied to achieve this aim include electrochemical biosensors, based on amperometric, potentiometric and impedance measurement, optical biosensors using surface plasmon resonance (SPR), optical fibers and piezoelectric biosensors based on microcantilevers. Future research also looks to the use of nanoparticles and novel nanomaterials as alternate recognition surfaces for use in a variety of sensor formats. PMID:21035597

Caygill, Rebecca L; Blair, G Eric; Millner, Paul A

2010-10-01

26

Highly pathogenic RNA viral infections: challenges for antiviral research.  

PubMed

A number of RNA viruses can cause severe disease when transmitted to humans from an animal reservoir. One of them, the recently emerged H5N1 subtype of influenza A virus, has caused several hundred cases of severe disease when transferred directly from domestic poultry. This or another avian subtype could potentially evolve to a form more transmissible by the respiratory route or reassort with a circulating strain to initiate a pandemic. Other zoonotic RNA viruses cause sporadic single cases or outbreaks of hemorrhagic fever or encephalitis that spread inefficiently from person-to-person, and thus remain confined to the geographic range of the maintenance host. RNA viral infections of farm animals, such as foot and mouth disease and classical swine fever, also pose a major threat to human well-being through economic loss and impaired nutrition. Only a few licensed antiviral drugs are available to prevent or treat these conditions. Medications that inhibit the replication of influenza virus might be used in an epidemic both to treat severe disease and to block the spread of infection. The guanosine analog ribavirin has been used to treat a few types of hemorrhagic fever, but there is no specific therapy for the others, or for any type of RNA viral encephalitis. The quest for new antivirals is being supported by government programs and new collaborative research networks. Major efforts will be required to identify active compounds, test their efficacy in laboratory animals, obtain approval for human use and develop rapid diagnostic methods that can identify patients early enough in the disease course for treatment to be of benefit. PMID:18243346

Bray, Mike

2008-01-10

27

Viral and Bacterial Pathogens in Bovine Respiratory Disease in Finland  

PubMed Central

Pathogens causing bovine respiratory tract disease in Finland were investigated. Eighteen cattle herds with bovine respiratory disease were included. Five diseased calves from each farm were chosen for closer examination and tracheobronchial lavage. Blood samples were taken from the calves at the time of the investigation and from 86 calves 3–4 weeks later. In addition, 6–10 blood samples from animals of different ages were collected from each herd, resulting in 169 samples. Serum samples were tested for antibodies to bovine parainfluenza virus-3 (PIV-3), bovine respiratory syncytial virus (BRSV), bovine coronavirus (BCV), bovine adenovirus-3 (BAV-3) and bovine adenovirus-7 (BAV-7). About one third of the samples were also tested for antibodies to bovine virus diarrhoea virus (BVDV) with negative results. Bacteria were cultured from lavage fluid and in vitro susceptibility to selected antimicrobials was tested. According to serological findings, PIV-3, BAV-7, BAV-3, BCV and BRSV are common pathogens in Finnish cattle with respiratory problems. A titre rise especially for BAV-7 and BAV-3, the dual growth of Mycoplasma dispar and Pasteurella multocida, were typical findings in diseased calves. Pasteurella sp. strains showed no resistance to tested antimicrobials. Mycoplasma bovis and Mannheimia haemolytica were not found.

Hartel, H; Nikunen, S; Neuvonen, E; Tanskanen, R; Kivela, S-L; Aho, P; Soveri, T; Saloniemi, H

2004-01-01

28

Antibody-based surface plasmon resonance detection of intact viral pathogen.  

PubMed

Surface plasmon resonance (SPR) technique was used to directly detect an intact form of insect pathogen: the baculovirus, Autographa californica multiple nuclear polyhedrosis virus (AcMNPV). An SPR sensor chip with three bio-functional layers was used to detect the intact AcMNPV: amine-reactive crosslinker with a disulfide bond that chemisorbs to gold film, Protein A, and a mouse IgG monoclonal antibody raised against a surface protein of the target viral pathogen. A two-channel (reference & test) micro-fluidic SPR system is used for reliable measurement. Bio-specific response to the AcMNPV is compared with the response for tobacco mosaic virus (TMV) as control. Successive exposure of the sensor chip to both viruses verifies a specific response to AcMNPV. This serves as a prerequisite to the development of a new type of viral pathogen detection sensors. PMID:16470580

Baac, Hyoungwon; Hajós, József P; Lee, Jennifer; Kim, Donghyun; Kim, Sung June; Shuler, Michael L

2006-07-01

29

Determination of major viral and sub viral pathogens incidence in apple orchards in himachal pradesh.  

PubMed

Apple is the major commercial horticulture crop in Himachal Pradesh and other hill states of Jammu & Kashmir, Uttarakhand and some parts of Northeastern states of India. In order to gather data on health status and incidence of virus and virus-like pathogens in apple orchards, survey was conducted in the month of June and September, 2010 in Hatkoti, Rohru, Kuthara, Jubbal and Khadapathar areas of major apple producing Shimla district of Himachal Pradesh. A total of 250 samples were collected and analyzed by DAS-ELISA, NASH and RT-PCR. NASH results indicated that a total of 117 samples were infected with Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV), Apple stem grooving virus (ASGV), Apple stem pitting virus (ASPV) and Apple scar skin viroid (ASSVd). Results showed that ASSVd is predominant in these areas with highest infection rate of 27.6% followed by ASPV (17.2%), ACLSV (16.8%), ApMV (15.2%) and ASGV (12%). Mixed infection of these viruses and viroid was frequently detected in apple trees in Himachal Pradesh. The trees, which were positive for viruses and viroids, showed a variety of fruit deformation and rusting symptoms besides leaf deformation, mosaic and chlorosis. PMID:23730008

Kumar, Surender; Singh, Rahul Mohan; Ram, Raja; Badyal, J; Hallan, Vipin; Zaidi, A A; Varma, Anupam

2011-12-09

30

Transcriptome analysis of Frog Virus 3, the type species of the genus Ranavirus, family Iridoviridae  

PubMed Central

Frog virus 3 is the best characterized species within the genus Ranavirus, family Iridoviridae. FV3's large (?105 kbp) dsDNA genome encodes 98 putative open reading frames (ORFs) that are expressed in a coordinated fashion leading to the sequential appearance of immediate early (IE), delayed early (DE) and late (L) viral transcripts. As a step toward elucidating molecular events in FV3 replication, we sought to identify the temporal class of viral messages. To accomplish this objective an oligonucleotide microarray containing 70-mer probes corresponding to each of the 98 FV3 ORFs was designed and used to examine viral gene expression. Viral transcription was initially monitored during the course of a productive replication cycle at 2, 4 and 9 hours after infection. To confirm results of the time course assay, viral gene expression was also monitored in the presence of cycloheximide (CHX), which limits expression to only IE genes, and following infection with a temperature sensitive (ts) mutant which at non-permissive temperatures is defective in viral DNA synthesis and blocked in late gene expression. Subsequently, microarray analyses were validated by RT-PCR and qRT-PCR. Using these approaches we identified 33 IE genes, 22 DE genes and 36 L viral genes. The temporal class of the 7 remaining genes could not be determined. Comparison of putative protein function with temporal class indicated that, in general, genes encoding putative regulatory factors, or proteins that played a part in nucleic acid metabolism and immune evasion, were classified as IE and DE genes, whereas those involved in DNA packaging and virion assembly were considered L genes. Information on temporal class will provide the basis for determining whether members of the same temporal class contain common upstream regulatory regions and perhaps allow us to identify virion-associated and virus-induced proteins that control viral gene expression.

Majji, S.; Thodima, V.; Sample, R.; Whitley, D.; Deng, Y.; Mao, J.; Chinchar, V. G.

2009-01-01

31

RNA Viral Community in Human Feces: Prevalence of Plant Pathogenic Viruses  

PubMed Central

The human gut is known to be a reservoir of a wide variety of microbes, including viruses. Many RNA viruses are known to be associated with gastroenteritis; however, the enteric RNA viral community present in healthy humans has not been described. Here, we present a comparative metagenomic analysis of the RNA viruses found in three fecal samples from two healthy human individuals. For this study, uncultured viruses were concentrated by tangential flow filtration, and viral RNA was extracted and cloned into shotgun viral cDNA libraries for sequencing analysis. The vast majority of the 36,769 viral sequences obtained were similar to plant pathogenic RNA viruses. The most abundant fecal virus in this study was pepper mild mottle virus (PMMV), which was found in high concentrations—up to 109 virions per gram of dry weight fecal matter. PMMV was also detected in 12 (66.7%) of 18 fecal samples collected from healthy individuals on two continents, indicating that this plant virus is prevalent in the human population. A number of pepper-based foods tested positive for PMMV, suggesting dietary origins for this virus. Intriguingly, the fecal PMMV was infectious to host plants, suggesting that humans might act as a vehicle for the dissemination of certain plant viruses.

Lee, Wah Heng; Run, Jin-Quan; Wei, Chia Lin; Soh, Shirlena Wee Ling; Hibberd, Martin L; Liu, Edison T; Rohwer, Forest

2006-01-01

32

Dose and host characteristics influence virulence of ranavirus infections.  

PubMed

Parasites play a prominent role in the ecology, evolution, and more recently, conservation of many organisms. For example, emerging infectious diseases, including a group of lethal ranaviruses, are associated with the declines and extinctions of amphibians around the world. An increasingly important basic and applied question is: what controls parasite virulence? We used a dose-response experiment with three laboratory-bred clutches of tiger salamander larvae (Ambystoma tigrinum) to test how the size of inoculum and host genetic factors influence the dynamics and outcome of ranavirus infections. We found that infection rates increased with dose and were strongly affected by clutch identity and host life history stage. Case mortality increased with dose of inoculum, but was unaffected by host characteristics. Average survival time decreased with dose and differed among clutches, but this was largely due to differences in the time to onset of symptoms. Overall, our results suggest that dose of inoculum and host characteristics (life history stage and genetic background) influence the establishment and early virus replication, and therefore the virulence of ranavirus infections. PMID:15891818

Brunner, Jesse L; Richards, Kathryn; Collins, James P

2005-09-16

33

A Decrease in Albumin in Early SIV Infection Is Related to Viral Pathogenicity  

PubMed Central

Abstract A decrease in circulating albumin levels after seroconversion has been reported as a predictor of disease progression in HIV-infected adults. We hypothesized that a similar decrease would be seen in pig-tailed macaques in early SIV infection, and that the degree of this decrease would be related to the pathogenicity of the infecting viral strain. Ten juvenile pig-tailed macaques were previously inoculated with virus derived from molecular clones representing different stages of infection: early (SIVMneCL8, n?=?2), intermediate (SIVMne35wkSU, n?=?2), late blood (SIVMne170, n?=?3), or late lymph node (SIVMne027, n?=?3). Albumin was measured in stored samples. Changes from baseline were evaluated by paired sample t tests and by linear regression with generalized estimating equations (GEE). Albumin levels decreased in the week after SIV inoculation (p?=?0.02), increased above baseline at week 5, then fell, returning below baseline by week 16 (p?=?0.03). In GEE modeling, albumin decreased significantly in both early and chronic infection (weeks 0–3, p?pathogenic virus variants. These results suggest that both early and late events in SIV pathogenesis are influenced by properties of the infecting viral strain.

Holte, Sarah; Kimata, Jason T.; Wener, Mark H.; Overbaugh, Julie

2009-01-01

34

The disinfection efficacy of a point-of-use water treatment system against bacterial, viral and protozoan waterborne pathogens  

Microsoft Academic Search

A point-of-use (POU) water treatment system (WTS), comprised of a presed activated carbon block filter followed by an ultraviolet (UV) light reactor, was evaluated for microbial disinfection efficacy following the general guidelines of the United States Environmental Protection Agency Guide Standard and Protocol for Testing Microbiological Water Purifiers. The POU WTS was challenged against bacterial, viral and protozoan waterborne pathogens

Morteza Abbaszadegan; Michaela N. Hasan; Charles P. Gerba; Peter F. Roessler; Barth R. Wilson; Roy Kuennen; Eric Van Dellen

1997-01-01

35

NANOMETRIC BASED METHODOLOGIES FOR SENSITIVE, HIGH THROUGHPUT DETECTION OF VIRAL PATHOGENS: SURFACE ENHANCED RAMAN SPECTROSCOPY AND ATOMIC FORCE MICROSCOPY  

Technology Transfer Automated Retrieval System (TEKTRAN)

The threat of bioterrorism has markedly amplified the demand for rapid, highly sensitive, and versatile diagnostic tests for a wide range of viral pathogens. This presentation describes efforts to develop immunoassay platforms that require minimal sample preparation and readout methodologies that fa...

36

Modelling the co-occurrence of Streptococcus pneumoniae with other bacterial and viral pathogens in the upper respiratory tract.  

PubMed

Otitis media (OM) is a major burden for all children, particularly for Australian Aboriginal children. Streptococcus pneumoniae, Moraxella catarrhalis, Haemophilus influenzae and viruses (including rhinovirus and adenovirus) are associated with OM. We investigated nasopharyngeal microbial interactions in 435 samples collected from 79 Aboriginal and 570 samples from 88 non-Aboriginal children in Western Australia. We describe a multivariate random effects model appropriate for analysis of longitudinal data, which enables the identification of two independent levels of correlation between pairs of pathogens. At the microbe level, rhinovirus infection was positively correlated with carriage of S. pneumoniae, H. influenzae and M. catarrhalis, and adenovirus with M. catarrhalis. Generally, there were positive associations between bacterial pathogens at both the host and microbe level. Positive viral-bacterial associations at the microbe level support previous findings indicating that viral infection can predispose an individual to bacterial carriage. Viral vaccines may assist in reducing the burden of bacterial disease. PMID:17030494

Jacoby, Peter; Watson, Kelly; Bowman, Jacinta; Taylor, Amanda; Riley, Thomas V; Smith, David W; Lehmann, Deborah

2006-09-22

37

PCR detection of ranavirus in adult anurans from the Louisville Zoological Garden.  

PubMed

Ranaviruses are known to cause mortality in a variety of anuran species and have the potential to significantly impact wild and captive frog populations. In this study, 16 captive frogs and toads from the Louisville Zoological Garden were examined for the presence of ranavirus; this group included 14 Cope's grey tree frogs (Hyla chrysoscelis), an American toad (Bufo americanus), and a southern toad (Bufo terrestris). All animals were wild caught and were evaluated via polymerase chain reaction (PCR), while animals that died were also assessed via histologic study to understand the role of ranaviral disease in these specimens. Of the animals that died, 82% were positive for ranavirus via PCR. Multiple swab samples collected over time from live tree frogs were positive for ranavirus via PCR. These findings reveal that ranaviral infection in captive adult anurans may occur without clinical signs or consistent histopathologic lesions. PMID:19746873

Driskell, Elizabeth A; Miller, Debra L; Swist, Shannon L; Gyimesi, Zoltan S

2009-09-01

38

Broad Distribution of Ranavirus in Free-Ranging Rana dybowskii in Heilongjiang, China  

Microsoft Academic Search

Ranaviruses have been associated with die-offs in cultured amphibians in China, but their presence in wild amphibians has\\u000a not yet been assessed. We sampled free-ranging Rana dybowskii at seven sites throughout Heilongjiang Province to determine the presence and prevalence of ranaviruses in this region. Our\\u000a results revealed an overall infection prevalence of 5.7% (18\\/315) for adults and 42.5% (51\\/120) for

Kai Xu; Dong-Ze Zhu; Ying Wei; Lisa M. Schloegel; Xiao-Feng Chen; Xiao-Long Wang

2010-01-01

39

Genes controlling vaccine responses and disease resistance to respiratory viral pathogens in cattle  

PubMed Central

Farm animals remain at risk of endemic, exotic and newly emerging viruses. Vaccination is often promoted as the best possible solution, and yet for many pathogens, either there are no appropriate vaccines or those that are available are far from ideal. A complementary approach to disease control may be to identify genes and chromosomal regions that underlie genetic variation in disease resistance and response to vaccination. However, identification of the causal polymorphisms is not straightforward as it generally requires large numbers of animals with linked phenotypes and genotypes. Investigation of genes underlying complex traits such as resistance or response to viral pathogens requires several genetic approaches including candidate genes deduced from knowledge about the cellular pathways leading to protection or pathology, or unbiased whole genome scans using markers spread across the genome. Evidence for host genetic variation exists for a number of viral diseases in cattle including bovine respiratory disease and anecdotally, foot and mouth disease virus (FMDV). We immunised and vaccinated a cattle cross herd with a 40-mer peptide derived from FMDV and a vaccine against bovine respiratory syncytial virus (BRSV). Genetic variation has been quantified. A candidate gene approach has grouped high and low antibody and T cell responders by common motifs in the peptide binding pockets of the bovine major histocompatibility complex (BoLA) DRB3 gene. This suggests that vaccines with a minimal number of epitopes that are recognised by most cattle could be designed. Whole genome scans using microsatellite and single nucleotide polymorphism (SNP) markers has revealed many novel quantitative trait loci (QTL) and SNP markers controlling both humoral and cell-mediated immunity, some of which are in genes of known immunological relevance including the toll-like receptors (TLRs). The sequencing, assembly and annotation of livestock genomes and is continuing apace. In addition, provision of high-density SNP chips should make it possible to link phenotypes with genotypes in field populations without the need for structured populations or pedigree information. This will hopefully enable fine mapping of QTL and ultimate identification of the causal gene(s). The research could lead to selection of animals that are more resistant to disease and new ways to improve vaccine efficacy.

Glass, Elizabeth J.; Baxter, Rebecca; Leach, Richard J.; Jann, Oliver C.

2012-01-01

40

Genes controlling vaccine responses and disease resistance to respiratory viral pathogens in cattle.  

PubMed

Farm animals remain at risk of endemic, exotic and newly emerging viruses. Vaccination is often promoted as the best possible solution, and yet for many pathogens, either there are no appropriate vaccines or those that are available are far from ideal. A complementary approach to disease control may be to identify genes and chromosomal regions that underlie genetic variation in disease resistance and response to vaccination. However, identification of the causal polymorphisms is not straightforward as it generally requires large numbers of animals with linked phenotypes and genotypes. Investigation of genes underlying complex traits such as resistance or response to viral pathogens requires several genetic approaches including candidate genes deduced from knowledge about the cellular pathways leading to protection or pathology, or unbiased whole genome scans using markers spread across the genome. Evidence for host genetic variation exists for a number of viral diseases in cattle including bovine respiratory disease and anecdotally, foot and mouth disease virus (FMDV). We immunised and vaccinated a cattle cross herd with a 40-mer peptide derived from FMDV and a vaccine against bovine respiratory syncytial virus (BRSV). Genetic variation has been quantified. A candidate gene approach has grouped high and low antibody and T cell responders by common motifs in the peptide binding pockets of the bovine major histocompatibility complex (BoLA) DRB3 gene. This suggests that vaccines with a minimal number of epitopes that are recognised by most cattle could be designed. Whole genome scans using microsatellite and single nucleotide polymorphism (SNP) markers has revealed many novel quantitative trait loci (QTL) and SNP markers controlling both humoral and cell-mediated immunity, some of which are in genes of known immunological relevance including the toll-like receptors (TLRs). The sequencing, assembly and annotation of livestock genomes and is continuing apace. In addition, provision of high-density SNP chips should make it possible to link phenotypes with genotypes in field populations without the need for structured populations or pedigree information. This will hopefully enable fine mapping of QTL and ultimate identification of the causal gene(s). The research could lead to selection of animals that are more resistant to disease and new ways to improve vaccine efficacy. PMID:21621277

Glass, Elizabeth J; Baxter, Rebecca; Leach, Richard J; Jann, Oliver C

2011-05-07

41

Interactions between viral and prokaryotic pathogens in a mixed infection with cardiovirus and mycoplasma.  

PubMed

In the natural environment, animal and plant viruses often share ecological niches with microorganisms, but the interactions between these pathogens, although potentially having important implications, are poorly investigated. The present report demonstrates, in a model system, profound mutual effects of mycoplasma and cardioviruses in animal cell cultures. In contrast to mycoplasma-free cells, cultures contaminated with Mycoplasma hyorhinis responded to infection with encephalomyocarditis virus (EMCV), a picornavirus, but not with poliovirus (also a picornavirus), with a strong activation of a DNase(s), as evidenced by the TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) immunofluorescence assay and electrophoretic analysis of host DNA. This degradation was reminiscent of that observed upon apoptosis but was caspase independent, judging by the failure of the specific pan-caspase inhibitor Q-VD-OPh to prevent it. The electrophoretic mobility of the enzyme responsible for DNA degradation and dependence of its activity on ionic conditions strongly suggested that it was represented by a DNase(s) of mycoplasma origin. In cells not infected with EMCV, the relevant DNase was dormant. The possibility is discussed that activation of the mycoplasma DNase might be linked to a relatively early increase in permeability of plasma membrane of the infected cells caused by EMCV. This type of unanticipated virus-mycoplasma "cooperation" may exemplify the complexity of pathogen-host interactions under conditions when viruses and microorganisms are infecting the same host. In the course of the present study, it was also demonstrated that pan-caspase inhibitor zVAD(OMe).fmk strongly suppressed cardiovirus polyprotein processing, illustrating an additional pitfall in investigations of viral effects on the apoptotic system of host cells. PMID:19605479

Lidsky, Peter V; Romanova, Lyudmila I; Kolesnikova, Marina S; Bardina, Maryana V; Khitrina, Elena V; Hato, Stanleyson V; van Kuppeveld, Frank J M; Agol, Vadim I

2009-07-15

42

Development of a real-time multiplex PCR assay for detection of viral pathogens of penaeid shrimp  

Microsoft Academic Search

A real-time multiplex polymerase chain reaction (rtm-PCR) assay was developed and optimized to simultaneously detect three\\u000a viral pathogens of shrimp in one reaction. Three sets of specific oligonucleotide primers for white spot syndrome virus (WSSV),\\u000a infectious hypodermal and haematopoietic necrosis virus (IHHNV) and Taura syndrome virus (TSV), along with three TaqMan probes\\u000a specific for each virus were used in the

Zhixun Xie; Liji Xie; Yaoshan Pang; Zhaofa Lu; Zhiqin Xie; Jianhua Sun; Xianwen Deng; Jiabo Liu; Xiaofei Tang; Mazhar Khan

2008-01-01

43

Production effects of pathogens causing bovine leukosis, bovine viral diarrhea, paratuberculosis, and neosporosis.  

PubMed

The primary purpose of this research was to determine associations among seropositivity for bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV), Mycobacterium avium ssp. paratuberculosis (MAP), and Neospora caninum (NC) and each of 3 outcome variables (305-d milk, fat, and protein production) in Canadian dairy cattle. Serum samples from up to 30 randomly selected cows from 342 herds on monthly milk testing were tested for antibodies against BLV (IDEXX ELISA; IDEXX Corporation, Westbrook, ME), MAP (IDEXX or Biocor ELISA; Biocor Animal Health, Inc., Omaha, NE), and NC (IDEXX or Biovet ELISA; Biovet Inc., St. Hyacinthe, Quebec, Canada). Up to 5 unvaccinated cattle over 6 mo of age were tested for virus-neutralizing antibodies to the Singer strain of type 1 BVDV. Dairy Herd Improvement records were obtained electronically for all sampled cows. Linear mixed models with herd and cow as random variables were fit, with significant restricted maximum likelihood estimates of outcome effects being obtained, while controlling for potential confounding variables. Bovine leukemia virus seropositivity was not associated with 305-d milk, 305-d fat, or 305-d protein production. Cows in BVDV-seropositive herds (at least one unvaccinated animal with a titer > or =1:64) had reductions in 305-d milk, fat, and protein of 368, 10.2, and 9.5 kg, respectively, compared with cows in BVDV-seronegative herds. Mycobacterium avium ssp. paratuberculosis seropositivity was associated with lower 305-d milk of 212 kg in 4+-lactation cows compared with MAP-seronegative 4+-lactation cows. Neospora caninum seropositivity in primiparous cows was associated with lower 305-d milk, fat, and protein of 158, 5.5, and 3.3 kg, respectively, compared with NC-seronegative primiparous cows. There were no interactions among seropositivity for any of the pathogens and their effects on any of the outcomes examined, although the low MAP seroprevalence limited this analysis. Results from this research will contribute to understanding the economic impacts of these pathogens and justify their control. PMID:17235141

Tiwari, A; Vanleeuwen, J A; Dohoo, I R; Keefe, G P; Haddad, J P; Tremblay, R; Scott, H M; Whiting, T

2007-02-01

44

Seroprevalences to Viral Pathogens in Free-Ranging and Captive Cheetahs (Acinonyx jubatus) on Namibian Farmland?  

PubMed Central

Cheetah populations are diminishing rapidly in their natural habitat. One reason for their decline is thought to be a high susceptibility to (infectious) diseases because cheetahs in zoos suffer from high disease-induced mortality. Data on the health status of free-ranging cheetahs are scarce, and little is known about their exposure and susceptibility to infectious diseases. We determined seroprevalences to nine key viruses (feline herpesvirus 1, feline calicivirus, feline parvovirus, feline coronavirus, canine distemper virus, feline immunodeficiency virus [FIV], puma lentivirus, feline leukemia virus, and rabies virus) in 68 free-ranging cheetahs on east-central Namibian farmland, 24 nonvaccinated Namibian captive cheetahs, and several other wild carnivore species and conducted necropsies of cheetahs and other wild carnivores. Eight of 11 other wild carnivores were seropositive for at least one of the viruses, including the first record of an FIV-like infection in a wild felid west of the Kalahari, the caracal (Felis caracal). Seroprevalences of the free-ranging cheetahs were below 5% for all nine viruses, which is significantly lower than seroprevalences in nonvaccinated captive cheetahs and those for five of seven viruses in previously studied free-ranging cheetahs from north-central Namibia (L. Munson, L. Marker, E. Dubovi, J. A. Spencer, J. F. Evermann, and S. J. O'Brien, J. Wildl. Dis. 40:23-31, 2004). There was no clinical or pathological evidence of infectious diseases in living or dead cheetahs. The results suggest that while free-ranging wild carnivores may be a source of pathogens, the distribution of seroprevalences across studies mirrored local human population density and factors associated with human habitation, probably reflecting contact opportunities with (nonvaccinated) domestic and feral cats and dogs. They also suggest that Namibian cheetahs respond effectively to viral challenges, encouraging consistent and sustainable conservation efforts.

Thalwitzer, Susanne; Wachter, Bettina; Robert, Nadia; Wibbelt, Gudrun; Muller, Thomas; Lonzer, Johann; Meli, Marina L.; Bay, Gert; Hofer, Heribert; Lutz, Hans

2010-01-01

45

Methods and compositions for identifying cellular genes exploited by viral pathogens.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Methods and compositions for rapidly identifying CGEPs required for viral infection of mammalian cells are provided. Also provided are methods of inhibiting viral infection of mammalian cells by inhibiting the activity of one or more CGEPs (e.g., as identified in accordance with methods of the inve...

46

Ranavirus infection of free-ranging and captive box turtles and tortoises in the United States.  

PubMed

Iridoviruses of the genus Ranavirus are well known for causing mass mortality events of fish and amphibians with sporadic reports of infection in reptiles. This article describes five instances of Ranavirus infection in chelonians between 2003 and 2005 in Georgia, Florida, New York, and Pennsylvania, USA. Affected species included captive Burmese star tortoises (Geochelone platynota), a free-ranging gopher tortoise (Gopherus polyphemus), free-ranging eastern box turtles (Terrapene carolina carolina), and a Florida box turtle (Terrepene carolina bauri). Evidence for Ranavirus infection was also found in archived material from previously unexplained mass mortality events of eastern box turtles from Georgia in 1991 and from Texas in 1998. Consistent lesions in affected animals included necrotizing stomatitis and/or esophagitis, fibrinous and necrotizing splenitis, and multicentric fibrinoid vasculitis. Intracytoplasmic inclusion bodies were rarely observed in affected tissues. A portion of the major capsid protein (MCP) gene was sequenced from each case in 2003-2005 and found to be identical to each other and to Frog virus 3 (FV3) across 420 base pairs. Ranavirus infections were also documented in sympatric species of amphibians at two locations with infected chelonians. The fragment profiles of HindIII-digested whole genomic DNA of Ranavirus, isolated from a dead Burmese star tortoise and a southern leopard frog (Rana utricularia) found nearby, were similar. The box turtle isolate had a low molecular weight fragment that was not seen in the digestion profiles for the other isolates. These results suggest that certain amphibians and chelonians are infected with a similar virus and that different viruses exist among different chelonians. Amphibians may serve as a reservoir host for susceptible chelonians. This report also demonstrated that significant disease associated with Ranavirus infections are likely more widespread in chelonians than previously suspected. PMID:18957641

Johnson, April J; Pessier, Allan P; Wellehan, James F X; Childress, April; Norton, Terry M; Stedman, Nancy L; Bloom, David C; Belzer, William; Titus, Valorie R; Wagner, Robert; Brooks, Jason W; Spratt, Jeffrey; Jacobson, Elliott R

2008-10-01

47

Experimental viral evolution reveals major histocompatibility complex polymorphisms as the primary host factors controlling pathogen adaptation and virulence.  

PubMed

Using an experimental evolution approach, we recently demonstrated that the mouse-specific pathogen Friend virus (FV) complex adapted to specific major histocompatibility complex (MHC) genotypes, which resulted in fitness tradeoffs when viruses were exposed to hosts possessing novel MHC polymorphisms. Here we report the analysis of patterns of pathogen adaptation and virulence evolution from viruses adapting to one of three hosts that differ across the entire genome (A/WySn, DBA/2J and BALB/c). We found that serial passage of FV complex through these mouse genotypes resulted in significant increases in pathogen fitness (156-fold) and virulence (11-fold). Adaptive responses by post-passage viruses also resulted in host-genotype-specific patterns of adaptation. To evaluate the relative importance of MHC versus non-MHC polymorphisms as factors influencing pathogen adaptation and virulence, we compared the magnitude of fitness tradeoffs incurred by post-passage viruses when infecting hosts possessing either novel MHC polymorphisms alone or hosts possessing novel MHC and non-MHC polymorphisms. MHC polymorphisms alone accounted for 71% and 83% of the total observed reductions in viral fitness and virulence in unfamiliar host genotypes, respectively. Strikingly, these data suggest that genetic polymorphisms within the MHC, a gene region representing only ?0.1% of the genome, are major host factors influencing pathogen adaptation and virulence evolution. PMID:23698707

Kubinak, J L; Ruff, J S; Cornwall, D H; Middlebrook, E A; Hasenkrug, K J; Potts, W K

2013-05-23

48

[Detection of viral infection pathogens in medicinal plants grown in Ukraine].  

PubMed

Monitoring of viral infection on medicinal plant plantations is carried out. Panax ginseng C.A. Meyer, Valeriana officinalis L., Plantago major L. with symptoms of viral infection were revealed. Viral nature of symptoms was proved with biotesting method. Morphology and sizes of virus particles, detected in Panax ginseng method. Morphology and sizes of virus particles, detected in Panax ginseng C.A. Meyer, Valeriana officinalis L., Plantago major L., were determined with electron microscopy method. The paper is presented in Ukrainian. PMID:19938607

Mishchenko, L T; Korenieva, A A; Molchanets', O V; Bo?ko, A L

49

INCREASING LEVELS OF ENVIRONMENTAL MUTAGENS: POTENTIAL FOR AFFECTING VIRAL EVOLUTION AND PATHOGENICITY - A SPECULATIVE REVIEW  

EPA Science Inventory

The author examines available data concerning the ways in which information contained in viral genomes is altered. echanisms of damage and repair of nucleic acids are discussed. nformation available on the rates of evolution of various viruses is summarized....

50

The Glycoprotein and the Matrix Protein of Rabies Virus Affect Pathogenicity by Regulating Viral Replication and Facilitating Cell-to-Cell Spread  

Microsoft Academic Search

Received 26 October 2007\\/Accepted 12 December 2007 While the glycoprotein (G) of rabies virus (RV) is known to play a predominant role in the pathogenesis of rabies, the function of the RV matrix protein (M) in RV pathogenicity is not completely clear. To further investigate the roles of these proteins in viral pathogenicity, we constructed chimeric recombinant viruses by exchanging

Rojjanaporn Pulmanausahakul; Jianwei Li; Matthias J. Schnell; Bernhard Dietzschold

2008-01-01

51

Major capsid protein gene sequence analysis of the Santee-Cooper ranaviruses DFV, GV6, and LMBV.  

PubMed

The Santee-Cooper ranaviruses doctor fish virus (DFV), guppy virus 6 (GV6), and largemouth bass virus (LMBV) are members of the genus Ranavirus within the family Iridoviridae. The major capsid protein (MCP) is a main structural protein of iridoviruses and supports the differentiation and classification of ranaviruses. Presently the complete sequence of the MCP gene is known for most ranaviruses with the exception of the Santee-Cooper ranaviruses. In the present study, the complete nucleotide sequence of the MCP gene of DFV, GV6, and LMBV was determined. DFV and GV6 are identical within the MCP gene sequence. The identity compared to the corresponding sequence in LMBV amounts to 99.21%. The MCP gene of DFV, GV6, and LMBV exhibits only approximately 78% identity compared to the respective gene of other ranaviruses. Based on the sequence data obtained in the present study, a Rana MCP polymerase chain reaction (PCR) and subsequent restriction fragment length polymorphism (RFLP) analysis were developed to identify and differentiate ranaviruses, including DFV, GV6, and LMBV. PMID:22132498

Ohlemeyer, S; Holopainen, R; Tapiovaara, H; Bergmann, S M; Schütze, H

2011-10-01

52

Simultaneous detection of viral and bacterial enteric pathogens using the Seeplex® Diarrhea ACE detection system.  

PubMed

A panel of 223 faecal samples was analysed to determine the clinical utility of the Seeplex® Diarrhea ACE Detection multiplex PCR system (Seeplex system; Seegene, Korea), a qualitative multiplexing PCR technology that enables simultaneous multi-pathogen detection of four viruses and/or ten bacteria associated with acute gastroenteritis. Conventional diagnostic methods and a norovirus-specific multiplex real-time RT–PCR detected 98 pathogens in 96 samples. The Seeplex system detected 81 pathogens in 75 samples. All samples positive for adenovirus, norovirus, Campylobacter spp., Escherichia coli O157, Shigella spp. or Vibrio spp. were detected by the Seeplex system. Rotavirus, Clostridium difficile toxin B, and Salmonella spp. were not detected in 12.5%, 50% and 15.8% of samples, respectively. Additional multiple infections were detected in 19 samples by the Seeplex system. The Seeplex system provides significant additional diagnostic capability for the syndromic diagnosis of acute gastroenteritis with increased sensitivity for the majority of pathogens. PMID:23211606

Coupland, L J; McElarney, I; Meader, E; Cowley, K; Alcock, L; Naunton, J; Gray, J

2012-12-05

53

On the role of RNA silencing in the pathogenicity and evolution of viroids and viral satellites  

Microsoft Academic Search

Viroids and most viral satellites have small, noncoding, and highly structured RNA genomes. How they cause disease symptoms without encoding proteins and why they have characteristic secondary structures are two longstanding questions. Recent studies have shown that both viroids and satellites are capable of inducing RNA silencing, suggesting a possible role of this mechanism in the pathology and evolution of

Ming-Bo Wang; Xue-Yu Bian; Li-Min Wu; Li-Xia Liu; Neil A. Smith; Daniel Isenegger; Rong-Mei Wu; Chikara Masuta; Vicki B. Vance; John M. Watson; Ali Rezaian; Elizabeth S. Dennis; Peter M. Waterhouse

2004-01-01

54

Persistence of viral pathogens and bacteriophages during sewage treatment: lack of correlation with indicator bacteria  

Microsoft Academic Search

The effects of different sewage treatments on the viral contamination in rivers which receive water from treatment plants without a final sand filtration step were investigated. They were all heavily contaminated with bacteriophages and human enteric viruses (detected by single step reverse transcription amplification followed by a nested polymerase chain reaction). Bacteriophages, but not faecal indicator organisms, were correlated with

Franca Baggi; Antonella Demarta; Raffaele Peduzzi

2001-01-01

55

Torque teno virus: an improved indicator for viral pathogens in drinking waters  

Microsoft Academic Search

BACKGROUND: Currently applied indicator organism systems, such as coliforms, are not fully protective of public health from enteric viruses in water sources. Waterborne disease outbreaks have occurred in systems that tested negative for coliforms, and positive coliform results do not necessarily correlate with viral risk. It is widely recognized that bacterial indicators do not co-occur exclusively with infectious viruses, nor

Jennifer S Griffin; Jeanine D Plummer; Sharon C Long

2008-01-01

56

Distribution of an Invasive Aquatic Pathogen (Viral Hemorrhagic Septicemia Virus) in the Great Lakes and Its Relationship to Shipping  

PubMed Central

Viral hemorrhagic septicemia virus (VHSV) is a rhabdovirus found in fish from oceans of the northern hemisphere and freshwaters of Europe. It has caused extensive losses of cultured and wild fish and has become established in the North American Great Lakes. Large die-offs of wild fish in the Great Lakes due to VHSV have alarmed the public and provoked government attention on the introduction and spread of aquatic animal pathogens in freshwaters. We investigated the relations between VHSV dispersion and shipping and boating activity in the Great Lakes by sampling fish and water at sites that were commercial shipping harbors, recreational boating centers, and open shorelines. Fish and water samples were individually analyzed for VHSV using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and cell culture assays. Of 1,221 fish of 17 species, 55 were VHSV positive with highly varied qRT-PCR titers (1 to 5,950,000 N gene copies). The detections of VHSV in fish and water samples were closely associated and the virus was detected in 21 of 30 sites sampled. The occurrence of VHSV was not related to type of site or shipping related invasion hotspots. Our results indicate that VHSV is widely dispersed in the Great Lakes and is both an enzootic and epizootic pathogen. We demonstrate that pathogen distribution information could be developed quickly and is clearly needed for aquatic ecosystem conservation, management of affected populations, and informed regulation of the worldwide trade of aquatic organisms.

Bain, Mark B.; Cornwell, Emily R.; Hope, Kristine M.; Eckerlin, Geofrey E.; Casey, Rufina N.; Groocock, Geoffrey H.; Getchell, Rodman G.; Bowser, Paul R.; Winton, James R.; Batts, William N.; Cangelosi, Allegra; Casey, James W.

2010-01-01

57

Viral proteins and Src family kinases: Mechanisms of pathogenicity from a "liaison dangereuse"  

PubMed Central

To complete their life cycle and spread, viruses interfere with and gain control of diverse cellular processes, this most often occurring through interaction between viral proteins (VPs) and resident protein partners. Among the latter, Src family kinases (SFKs), a class of non-receptor tyrosine kinases that contributes to the conversion of extracellular signals into intracellular signaling cascades and is involved in virtually all cellular processes, have recently emerged as critical mediators between the cell’s infrastructure and the viral demands. In this scenario, structural or ex novo synthesized VPs are able to bind to the different domains of these enzymes through specific short linear motifs present along their sequences. Proline-rich motifs displaying the conserved minimal consensus PxxP and recognizing the SFK Src homology (SH)3 domain constitute a cardinal signature for the formation of multiprotein complexes and this interaction may promote phosphorylation of VPs by SFKs, thus creating phosphotyrosine motifs that become a docking site for the SH2 domains of SFKs or other SH2 domain-bearing signaling molecules. Importantly, the formation of these assemblies also results in a change in the activity and/or location of SFKs, and these events are critical in perturbing key signaling pathways so that viruses can utilize the cell’s machinery to their own benefit. In the light of these observations, although VPs as such, especially those with enzyme activity, are still regarded as valuable targets for therapeutic strategies, multiprotein complexes composed of viral and host cell proteins are increasingly becoming objects of investigation with a view to deeply characterize the structural aspects that favor their formation and to develop new compounds able to contrast viral diseases in an alternative manner.

Pagano, Mario Angelo; Tibaldi, Elena; Palu, Giorgio; Brunati, Anna Maria

2013-01-01

58

Vaccine-Induced Cellular Immune Responses Reduce Plasma Viral Concentrations after Repeated Low-Dose Challenge with Pathogenic Simian Immunodeficiency Virus SIVmac239  

Microsoft Academic Search

The goal of an AIDS vaccine regimen designed to induce cellular immune responses should be to reduce the viral set point and preserve memory CD4 lymphocytes. Here we investigated whether vaccine-induced cellular immunity in the absence of any Env-specific antibodies can control viral replication following multiple low-dose challenges with the highly pathogenic SIVmac239 isolate. Eight Mamu-A*01-positive Indian rhesus macaques were

Nancy A. Wilson; Jason Reed; Gnankang S. Napoe; Shari Piaskowski; Andy Szymanski; Jessica Furlott; Edna J. Gonzalez; Levi J. Yant; Nicholas J. Maness; Gemma E. May; Taeko Soma; Matthew R. Reynolds; Eva Rakasz; Richard Rudersdorf; Adrian B. McDermott; David H. O'Connor; Thomas C. Friedrich; David B. Allison; Amit Patki; Louis J. Picker; Dennis R. Burton; Jing Lin; Lingyi Huang; Deepa Patel; G. Heindecker; J. Fan; M. Citron; M. Horton; F. Wang; X. Liang; J. W. Shiver; D. R. Casimiro; D. I. Watkins

2006-01-01

59

DEVELOPMENT OF A BIOMARKER SYSTEM FOR DETECTING EXPOSURE TO WATERBORNE VIRAL PATHOGENS  

EPA Science Inventory

EPA has published a drinking water contaminant candidate list (CCL) that includes waterborne pathogens and chemicals that may be considered for regulation at a future date. For each contaminant on the CCL, the Agency will need sufficient data to conduct analyses on the extent of...

60

Production of transgenic rainbow trout resistant to infection by bacterial and viral pathogens  

Technology Transfer Automated Retrieval System (TEKTRAN)

Exploiting the natural microbe-defense (innate defense) mechanism, originally discovered in insects and subsequently found in many animal species, may lead to the development of a novel approach for protecting commercially important finfish and crustacean species from infection by microbial pathogen...

61

The role of amphibian antimicrobial peptides in protection of amphibians from pathogens linked to global amphibian declines  

Microsoft Academic Search

Amphibian species have experienced population declines and extinctions worldwide that are unprecedented in recent history. Many of these recent declines have been linked to a pathogenic skin fungus, Batrachochytrium dendrobatidis, or to iridoviruses of the genus Ranavirus. One of the first lines of defense against pathogens that enter by way of the skin are antimicrobial peptides synthesized and stored in

Louise A. Rollins-Smith

2009-01-01

62

Prevalence of viral and bacterial sexually transmitted pathogens in Jamaican pregnant women.  

PubMed

In this study we investigated the prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, human immunodeficiency virus type I (HIV-I), human T cell lymphotropic virus type 1 (HTLV-1) and hepatitis B virus (HBV) infections in 200 pregnant women attending antenatal clinics at the University Hospital of the West Indies. 19% of the women had at least one pathogen: C. trachomatis was found in 16%, HTLV-1 in 2%, HIV-1, HBV and N. gonorrhoeae each in 0.5% C. trachomatis infection was more prevalent in women less than 20 years of age (31%) than in those 20 years and older (16%; OR = 0.43; chi 2 = 5.66; p < 0.05). The study demonstrates the need for identification of sexually transmitted pathogens in antenatal women for syndromic management of genital infections as part of the strategy for prevention and control of HIV/AIDS (acquired immunodeficiency syndrome) in Jamaica. PMID:9619092

Dowe, G; King, S D; Smikle, M F; Wynter, H H; Chout, R; Klaskala, W

1998-03-01

63

Pathogenicity of diatraea saccharalis densovirus to host insets and characterization of its viral genome  

Microsoft Academic Search

Pathogenicity of the Diatraea saccharalis densovirus (DsDNV) was tested on its host larvae. The results showed that up to\\u000a 4 days after inoculation, no larvae mortality was observed and the infected larvae started to exhibit the infection symptoms\\u000a from the fourth day. After 5 days of infection, the cumulative mortality of infected larvae increased significantly and reached\\u000a 60% after 12

Nazaire Kouassi; Jian-xin Peng; Yi Li; Cristina Cavallaro; Jean-Claude Veyrunes; Max Bergoin

2007-01-01

64

Occurrence of Immunoglobulin M Antibodies against Several Bacterial and Viral Pathogens in Acute Hantavirus Infection  

PubMed Central

Elevated levels of immunoglobulin M antibodies against various pathogens, most frequently Epstein-Barr-virus and Coxiella burnetii, were detected by immunoassay in 15 of 48 patients (31.3%) with acute Puumala virus infections. Although the mechanisms leading to this IgM response are not clear yet, polyspecific immunoglobulin M antibodies have to be taken into account to avoid misinterpretation of serological results in acute hantavirus infection.

Goetz, Andrea; Weber, Ursula

2012-01-01

65

Occurrence of immunoglobulin M antibodies against several bacterial and viral pathogens in acute hantavirus infection.  

PubMed

Elevated levels of immunoglobulin M antibodies against various pathogens, most frequently Epstein-Barr-virus and Coxiella burnetii, were detected by immunoassay in 15 of 48 patients (31.3%) with acute Puumala virus infections. Although the mechanisms leading to this IgM response are not clear yet, polyspecific immunoglobulin M antibodies have to be taken into account to avoid misinterpretation of serological results in acute hantavirus infection. PMID:22787199

Wellinghausen, Nele; Goetz, Andrea; Weber, Ursula

2012-07-11

66

Impact of Piriformospora indica on tomato growth and on interaction with fungal and viral pathogens  

Microsoft Academic Search

Piriformospora indica is a root endophytic fungus with plant-promoting properties in numerous plant species and induces resistance against root\\u000a and shoot pathogens in barley, wheat, and Arabidopsis. A study over several years showed that the endophyte P. indica colonised the roots of the most consumed vegetable crop tomato. P. indica improved the growth of tomato resulting in increased biomass of

Ahmad Fakhro; Diana Rocío Andrade-Linares; Susanne von Bargen; Martina Bandte; Carmen Büttner; Rita Grosch; Dietmar Schwarz; Philipp Franken

2010-01-01

67

Bacterial and Viral Pathogens in Live Oysters: 2007 United States Market Survey ?  

PubMed Central

Two samples of market oysters, primarily from retail establishments, were collected twice each month in each of nine states during 2007. Samples were shipped refrigerated overnight to five U.S. Food and Drug Administration laboratories on a rotating basis and analyzed by most probable number (MPN) for total and pathogenic Vibrio parahaemolyticus and V. vulnificus numbers and for the presence of toxigenic V. cholerae, Salmonella spp., norovirus (NoV), and hepatitis A virus (HAV). Levels of indicator organisms, including fecal coliforms (MPN), Escherichia coli (MPN), male-specific bacteriophage, and aerobic plate counts, were also determined. V. parahaemolyticus and V. vulnificus levels were distributed seasonally and geographically by harvest region and were similar to levels observed in a previous study conducted in 1998-1999. Levels of pathogenic V. parahaemolyticus were typically several logs lower than total V. parahaemolyticus levels regardless of season or region. Pathogenic V. parahaemolyticus levels in the Gulf and Mid-Atlantic regions were about two logs greater than the levels observed in the Pacific and North Atlantic regions. Pathogens generally associated with fecal pollution were detected sporadically or not at all (toxigenic V. cholerae, 0%; Salmonella, 1.5%; NoV, 3.9%; HAV, 4.4%). While seasonal prevalences of NoV and HAV were generally greater in oysters harvested from December to March, the low detection frequency obscured any apparent seasonal effects. Overall, there was no relationship between the levels of indicator microorganisms and the presence of enteric viruses. These data provide a baseline that can be used to further validate risk assessment predictions, determine the effectiveness of new control measures, and compare the level of protection provided by the U.S. shellfish sanitation system to those in other countries.

DePaola, Angelo; Jones, Jessica L.; Woods, Jacquelina; Burkhardt, William; Calci, Kevin R.; Krantz, Jeffrey A.; Bowers, John C.; Kasturi, Kuppuswamy; Byars, Robin H.; Jacobs, Emily; Williams-Hill, Donna; Nabe, Khamphet

2010-01-01

68

Co-occurrence of viral and bacterial pathogens in disease outbreaks affecting newly cultured sparid fish.  

PubMed

Several microbial disease outbreaks in farm stocks of newly cultured sparid fish species, such as common seabream, redbanded seabream, and white seabream, were recorded from 2004 to 2006. This study describes the isolation and characterization of the potential causative agents, either bacteria or viruses, of these outbreaks. The isolated bacterial strains were characterized according to traditional taxonomical analyses and sequencing of a 16S rDNA fragment. Most bacteria were identified as Vibrio spp. and Photobacterium damselae subsp. damselae. The development of cytopathic effects (CPE) on different fish cell lines, the application of specific nested-PCR tests for infectious pancreatic necrosis virus (IPNV), viral nervous necrosis virus (VNNV) and viral hemorrhagic septicemia virus (VHSV), and subsequent sequence analyses were used for virus detection and identification. VNNV, related to the striped jack neural necrosis virus (SJNNV) genotype, and VHSV, related to the genotype Ia, were the only viruses detected. VNNV was isolated from the three fish species under study in five different outbreaks, whereas VHSV was isolated from common seabream and white seabream during two of these outbreaks. IPNV was not detected in any case. PMID:18076001

García-Rosado, Esther; Cano, Irene; Martín-Antonio, Beatriz; Labella, Alejandro; Manchado, Manuel; Alonso, M Carmen; Castro, Dolores; Borrego, Juan J

2007-09-01

69

Identification of viral pathogens in aborted fetuses and stillborn piglets from cases of swine reproductive failure in Spain.  

PubMed

The objective of the present study was to determine the presence of recognised abortifacient viruses such as porcine reproductive and respiratory virus (PRRSV), Aujeszky's disease virus (ADV), porcine parvovirus (PPV) and porcine circovirus type 2 (PCV2), in tissues from aborted fetuses and stillborn neonates in cases of late reproductive failure in swine. A total of 293 specimens (fetuses aborted in the last third of gestation and stillborn piglets) from 100 different cases of late-term abortions and premature farrowing from 15 different Spanish provinces were studied. PRRSV was detected in 9/100 cases by RT-PCR. Only 1/100 cases analysed (corresponding to a late-term aborted fetus with a negative PRRSV RT-PCR result) was positive for PCV2 by PCR. Neither ADV (monitored by viral isolation plus antigen detection) nor PPV (monitored by ELISA antigen capture test) infection was identified. The results suggest that PRRSV is one of the most important infectious agents, if not the most relevant one, associated with fetal infection leading to abortion or premature farrowing in Spain. Moreover, other viral pathogens such as ADV, PPV and PCV2 seem to have a minor impact on reproductive disease. PMID:15848788

Maldonado, J; Segalés, J; Martínez-Puig, D; Calsamiglia, M; Riera, P; Domingo, M; Artigas, C

2005-05-01

70

A host-restricted viral vector for antigen-specific immunization against Lyme disease pathogen.  

PubMed

Newcastle disease virus (NDV) is an avian virus that is attenuated in primates and is a potential vaccine vector for human use. We evaluated NDV as a vector for expressing selected antigens of the Lyme disease pathogen Borrelia burgdorferi. A series of recombinant NDVs were generated that expressed intracellular or extracellular forms of two B. burgdorferi antigens: namely, the basic membrane protein A (BmpA) and the outer surface protein C (OspC). Expression of the intracellular and extracellular forms of these antigens was confirmed in cultured chicken cells. C3H or Balb/C mice that were immunized intranasally with the NDV vectors mounted vigorous serum antibody responses against the NDV vector, but failed to mount a robust response against either the intracellular or extracellular forms of BmpA or OspC. By contrast, a single immunization of hamsters with the NDV vectors via the intranasal, intramuscular, or intraperitoneal route resulted in rapid and rigorous antibody responses against the intracellular or extracellular forms of BmpA and OspC. When groups of hamsters were separately inoculated with various NDV vectors and challenged with B. burgdorferi (10(8)cells/animal), immunization with vector expressing either intracellular or extracellular BmpA was associated with a significant reduction of the pathogen load in the joints. Taken together, our studies highlighted the importance of NDV as vaccine vector that can be used for simple yet effective immunization of hosts against bacterial infections including Lyme disease. PMID:21600949

Xiao, Sa; Kumar, Manish; Yang, Xiuli; Akkoyunlu, Mustafa; Collins, Peter L; Samal, Siba K; Pal, Utpal

2011-05-19

71

A host-restricted viral vector for antigen-specific immunization against Lyme disease pathogen  

PubMed Central

Newcastle disease virus (NDV) is an avian virus that is attenuated in primates and is a potential vaccine vector for human use. We evaluated NDV as a vector for expressing selected antigens of the Lyme disease pathogen Borrelia burgdorferi. A series of recombinant NDVs were generated that expressed intracellular or extracellular forms of two Borrelia burgdorferi antigens: namely, the basic membrane protein A (BmpA) and the outer surface protein C (OspC). Expression of the intracellular and extracellular forms of these antigens was confirmed in cultured chicken cells. C3H or Balb/C mice that were immunized intranasally with the NDV vectors mounted vigorous serum antibody responses against the NDV vector, but failed to mount a robust response against either the intracellular or extracellular forms of BmpA or OspC. In contrast, a single immunization of hamsters with the NDV vectors via the intranasal, intramuscular, or intraperitoneal route resulted in rapid and rigorous antibody responses against the intracellular or extracellular forms of BmpA and OspC. When groups of hamsters were separately inoculated with various NDV vectors and challenged with B. burgdorferi (108 cells/animal), immunization with vector expressing either intracellular or extracellular BmpA was associated with a significant reduction of the pathogen load in the joints. Taken together, our studies highlighted the importance of NDV as vaccine vector that can be used for simple yet effective immunization of hosts against bacterial infections including Lyme disease.

Xiao, Sa; Kumar, Manish; Yang, Xiuli; Akkoyunlu, Mustafa; Collins, Peter L.; Samal, Siba K.; Pal, Utpal

2011-01-01

72

Viral DNA sequences of genes encoding the ATPase and the major capsid protein of tropical iridovirus isolates which are pathogenic to fishes in Japan, South China Sea and Southeast Asian countries.  

PubMed

Tropical iridovirus infection causes severe epizootic resulting in mass mortalities and large economic losses in freshwater ornamental fishes cultured in Southeast Asian countries, in wild fish seedlings captured in South China Sea, and in marine fishes farmed in Japan, Singapore, and Thailand. All of tropical iridovirus-infected fishes histopathologically showed the systemic formation of inclusion body-bearing cells and necrosis of virus-infected splenocytes and hematopoietic cells. We designed primer sets for the ATPase gene and the major capsid protein (MCP) gene and sequenced the PCR products derived from 5 iridovirus isolates from sea bass in South China Sea, red sea bream in Japan, brown-spotted grouper with a grouper sleepy disease in Thailand, dwarf gourami from Malaysia and African lampeye from Sumatra Island, Indonesia. The ATPase gene and the MCP gene of these 5 viral isolates were highly homologous (> 95.8%, > 94.9% identity, respectively) and the deduced amino acid sequences of the ATPase and the MCP were also highly identical (> 98.1%, > 97.2% identity, respectively). Based on the high homology, these 5 isolates of tropical iridovirus from various fishes in geographically different regions were determined to have a single origin and to be native to Southeast Asian regions. However, these sequences were far different from those of members of the genera Ranavirus, Lymphocystivirus and Iridovirus in the Family Iridoviridae. We propose a new genus "Tropivirus" for tropical iridovirus in the Family Iridoviridae. PMID:12417946

Sudthongkong, C; Miyata, M; Miyazaki, T

2002-11-01

73

Human Monoclonal Antibodies Against a Plethora of Viral Pathogens From Single Combinatorial Libraries  

NASA Astrophysics Data System (ADS)

Conventional antibody generation usually requires active immunization with antigen immediately prior to the preparation procedure. Combinatorial antibody library technology offers the possibility of cloning a range of antibody specificities at a single point in time and then accessing these specificities at will. Here we show that human monoclonal antibody Fab fragments against a plethora of infectious agents can be readily derived from a single library. Further examination of a number of libraries shows that whenever antibody against a pathogen can be detected in the serum of the donor, then specific antibodies can be derived from the corresponding library. We describe the generation of human Fab fragments against herpes simplex virus types 1 and 2, human cytomegalovirus, varicella zoster virus, rubella, human immunodeficiency virus type 1, and respiratory syncytial virus. The antibodies are shown to be highly specific and a number are effective in neutralizing virus in vitro.

Williamson, R. Anthony; Burioni, Roberto; Sanna, Pietro P.; Partridge, Lynda J.; Barbas, Carlos F., III; Burton, Dennis R.

1993-05-01

74

Viral pneumonia.  

PubMed

Viral pneumonias are common in infants and young children but rare in adults. Respiratory syncytial virus (RSV) and para-influenza viruses are the most frequent viral pathogens in infants and children. Influenza virus types A and B account for over one half of viral pneumonias in adults. Immunocompromised hosts are susceptible to pneumonias caused by cytomegalovirus (CMV) and other herpesviruses, as well as rubeola and adenovirus. Diagnosis of viral pneumonia depends on appropriate viral cultures and acute and convalescent sera for specific antibodies. Superinfection with bacteria is common in adults. Anti-viral therapy is available for several respiratory viruses. Ribavirin, amantadine/rimantadine, interferon alpha, and acyclovir are antiviral drugs that may be of benefit in treatment and prophylaxis. Prevention of viral pneumonia will depend upon improved viral immunization practices. PMID:1659594

Greenberg, S B

1991-09-01

75

Impact of Piriformospora indica on tomato growth and on interaction with fungal and viral pathogens.  

PubMed

Piriformospora indica is a root endophytic fungus with plant-promoting properties in numerous plant species and induces resistance against root and shoot pathogens in barley, wheat, and Arabidopsis. A study over several years showed that the endophyte P. indica colonised the roots of the most consumed vegetable crop tomato. P. indica improved the growth of tomato resulting in increased biomass of leaves by up to 20%. Limitation of disease severity caused by Verticillium dahliae by more than 30% was observed on tomato plants colonised by the endophyte. Further experiments were carried out in hydroponic cultures which are commonly used for the indoor production of tomatoes in central Europe. After adaptation of inoculation techniques (inoculum density, plant stage), it was shown that P. indica influences the concentration of Pepino mosaic virus in tomato shoots. The outcome of the interaction seems to be affected by light intensity. Most importantly, the endophyte increases tomato fruit biomass in hydroponic culture concerning fresh weight (up to 100%) and dry matter content (up to 20%). Hence, P. indica represents a suitable growth promoting endophyte for tomato which can be applied in production systems of this important vegetable plant not only in soil, but also in hydroponic cultures. PMID:19789897

Fakhro, Ahmad; Andrade-Linares, Diana Rocío; von Bargen, Susanne; Bandte, Martina; Büttner, Carmen; Grosch, Rita; Schwarz, Dietmar; Franken, Philipp

2009-09-30

76

Development of Multiplex PCRs for Detection of Common Viral Pathogens and Agents of Congenital Infections  

PubMed Central

Potential causes of congenital infection include Toxoplasma gondii and viruses such as cytomegalovirus (CMV), enterovirus, hepatitis C virus, herpes simplex virus types 1 and 2 (HSV-1 and -2), human herpesvirus types 6, 7, and 8, lymphocytic choriomeningitis virus, parvovirus, rubella virus, and varicella-zoster virus. Testing for each of these agents using nucleic acid tests is time consuming and the availability of clinical samples such as amniotic fluid or neonatal blood is often limited. The aim of this study was to develop multiplex PCRs (mPCRs) for detection of DNA and RNA agents in the investigation of congenital infection and an mPCR for the viruses most commonly requested in a diagnostic virology laboratory (CMV, Epstein-Barr virus, enterovirus, HSV-1, HSV-2, and varicella-zoster virus). The assays were assessed using known pathogen-positive tissues (cultures, placentae, plasma, and amniotic fluid) and limits of detection were determined for all the agents studied using serial dilutions of plasmid targets. Nested PCR was performed as the most sensitive assay currently available, and detection of the amplicons using hybridization to labeled probes and enzyme-linked immunosorbent assay detection was incorporated into three of the four assays. This allowed detection of 10 to 102 copies of each agent in the samples processed. In several patients, an unexpected infection was diagnosed, including a case of encephalitis where HSV was the initial clinical suspicion but CMV was detected. In the majority of these cases the alternative agent could be confirmed using reference culture, serology, or fluorescence methods and was of relevance to clinical care of the patient. The methods described here provide useful techniques for diagnosing congenital infections and a paradigm for assessment of new multiplex PCRs for use in the diagnostic laboratory.

McIver, C. J.; Jacques, C. F. H.; Chow, S. S. W.; Munro, S. C.; Scott, G. M.; Roberts, J. A.; Craig, M. E.; Rawlinson, W. D.

2005-01-01

77

PCR prevalence of Ranavirus in free-ranging eastern box turtles (Terrapene carolina carolina) at rehabilitation centers in three southeastern US states.  

PubMed

Ranaviruses (genus Ranavirus) have been observed in disease epidemics and mass mortality events in free-ranging amphibian, turtle, and tortoise populations worldwide. Infection is highly fatal in turtles, and the potential impact on endangered populations could be devastating. Our objectives were to determine the prevalence of ranavirus DNA in blood and oral swabs, report associated clinical signs of infection, and determine spatial distribution of infected turtles. Blood and oral swabs were taken from 140 eastern box turtles (Terrapene carolina carolina) that were presented to the wildlife centers at the University of Tennessee (UT; n=39), Wildlife Center of Virginia (WCV; n=34), and North Carolina State University (NCSU; n=36), as well as a free-ranging nonrehabilitation population near Oak Ridge, Tennessee (OR; n=39) March-November 2007. Samples were evaluated for ranavirus infection using polymerase chain reaction (PCR) targeting a conserved portion of the major capsid protein. Two turtles, one from UT and one from NCSU, had evidence of ranavirus infection; sequences of PCR products were 100% homologous to Frog Virus 3. Prevalence of ranavirus DNA in blood was 3, 0, 3, and 0% for UT, WCV, NCSU, and OR, respectively. Prevalence in oral swab samples was 3, 0, and 0% for UT, WCV, and NCSU, respectively. Wildlife centers may be useful in detection of Ranavirus infection and may serve as a useful early monitoring point for regional disease outbreaks. PMID:21719848

Allender, Matthew C; Abd-Eldaim, Mohamed; Schumacher, Juergen; McRuer, David; Christian, Larry S; Kennedy, Melissa

2011-07-01

78

Pinellia ternata agglutinin expression in chloroplasts confers broad spectrum resistance against aphid, whitefly, Lepidopteran insects, bacterial and viral pathogens.  

PubMed

Broad spectrum protection against different insects and pathogens requires multigene engineering. However, such broad spectrum protection against biotic stress is provided by a single protein in some medicinal plants. Therefore, tobacco chloroplasts were transformed with the agglutinin gene from Pinellia ternata (pta), a widely cultivated Chinese medicinal herb. Pinellia ternata agglutinin (PTA) was expressed up to 9.2% of total soluble protein in mature leaves. Purified PTA showed similar hemagglutination activity as snowdrop lectin. Artificial diet with purified PTA from transplastomic plants showed marked and broad insecticidal activity. In planta bioassays conducted with T0 or T1 generation PTA lines showed that the growth of aphid Myzus persicae (Sulzer) was reduced by 89%-92% when compared with untransformed (UT) plants. Similarly, the larval survival and total population of whitefly (Bemisia tabaci) on transplastomic lines were reduced by 91%-93% when compared with UT plants. This is indeed the first report of lectin controlling whitefly infestation. When transplastomic PTA leaves were fed to corn earworm (Helicoverpa zea), tobacco budworm (Heliothis virescens) or the beet armyworm (spodoptera exigua), 100% mortality was observed against all these three insects. In planta bioassays revealed Erwinia population to be 10,000-fold higher in control than in PTA lines. Similar results were observed with tobacco mosaic virus (TMV) challenge. Therefore, broad spectrum resistance to homopteran (sap-sucking), Lepidopteran insects as well as anti-bacterial or anti-viral activity observed in PTA lines provides a new option to engineer protection against biotic stress by hyper-expression of an unique protein that is naturally present in a medicinal plant. PMID:22077160

Jin, Shuangxia; Zhang, Xianlong; Daniell, Henry

2011-11-13

79

Increased pathogenicity of European porcine reproductive and respiratory syndrome virus is associated with enhanced adaptive responses and viral clearance.  

PubMed

Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically important diseases of swine worldwide. Since its first emergence in 1987 the PRRS virus (PRRSV) has become particularly divergent with highly pathogenic strains appearing in both Europe and Asia. However, the underlying mechanisms of PRRSV pathogenesis are still unclear. This study sets out to determine the differences in pathogenesis between subtype 1 and 3 strains of European PRRSV (PRRSV-I), and compare the immune responses mounted against these strains. Piglets were infected with 3 strains of PRRSV-I: Lelystad virus, 215-06 a British field strain and SU1-bel from Belarus. Post-mortem examinations were performed at 3 and 7 days post-infection (dpi), and half of the remaining animals in each group were inoculated with an Aujeszky's disease (ADV) vaccine to investigate possible immune suppression resulting from PRRSV infection. The subtype 3 SU1-bel strain displayed greater clinical signs and lung gross pathology scores compared with the subtype 1 strains. This difference did not appear to be caused by higher virus replication, as viraemia and viral load in broncho-alveolar lavage fluid (BALF) were lower in the SU1-bel group. Infection with SU1-bel induced an enhanced adaptive immune response with greater interferon (IFN)-? responses and an earlier PRRSV-specific antibody response. Infection with PRRSV did not affect the response to vaccination against ADV. Our results indicate that the increased clinical and pathological effect of the SU1-bel strain is more likely to be caused by an enhanced inflammatory immune response rather than higher levels of virus replication. PMID:23313323

Morgan, S B; Graham, S P; Salguero, F J; Sánchez Cordón, P J; Mokhtar, H; Rebel, J M J; Weesendorp, E; Bodman-Smith, K B; Steinbach, F; Frossard, J P

2012-11-29

80

Marine Viral Pathogens.  

National Technical Information Service (NTIS)

The research funded by this award, sponsored investigations on novel marine viruses that were isolated in British Columbia coastal waters and the Gulf of Mexico. It was a continuation of Grant NOOOl4-92-J-l676 awarded at The University of Texas. The resul...

C. Suttle

1998-01-01

81

Viral infection  

PubMed Central

Viruses have developed different survival strategies in host cells by crossing cell-membrane compartments, during different steps of their viral life cycle. In fact, the non-regenerative viral membrane of enveloped viruses needs to encounter the dynamic cell-host membrane, during early steps of the infection process, in which both membranes fuse, either at cell-surface or in an endocytic compartment, to promote viral entry and infection. Once inside the cell, many viruses accomplish their replication process through exploiting or modulating membrane traffic, and generating specialized compartments to assure viral replication, viral budding and spreading, which also serve to evade the immune responses against the pathogen. In this review, we have attempted to present some data that highlight the importance of membrane dynamics during viral entry and replicative processes, in order to understand how viruses use and move through different complex and dynamic cell-membrane structures and how they use them to persist.

Puigdomenech, Isabel; de Armas-Rillo, Laura; Machado, Jose-David

2011-01-01

82

Simultaneous Genomic Detection of Multiple Enteric Bacterial and Viral Pathogens, Including SARS-CoV and RVFV.  

National Technical Information Service (NTIS)

A multiplexed screening system to detect pathogenicity islands (PI) of bacteria causing enteric disease and pathogenicity factors (PF) associated with the SARS-associated coronavirus (SARS-CoV) and Rift Valley Fever Virus (RVFV) has been developed. Pathog...

S. Payne C. J. Peters S. Makino K. Oliver C. Weiss

2004-01-01

83

Simultaneous Genomic Detection of Multiple Enteric Bacterial and Viral Pathogens, Including Sars-CoV and RVFV.  

National Technical Information Service (NTIS)

A multiplexed screening system to detect pathogenicity islands (PI) of bacteria causing enteric disease and pathogenicity factors (PF) associated with the SARS-associated coronavirus (SARS-CoV) and Rift Valley Fever Virus (RVFV) has been developed. This s...

S. Payne C. J. Peters S. Makino K. Oliver C. Weiss

2004-01-01

84

Ac23, an Envelope Fusion Protein Homolog in the Baculovirus Autographa californica Multicapsid Nucleopolyhedrovirus, Is a Viral Pathogenicity Factor  

Microsoft Academic Search

Viral envelope fusion proteins are important structural proteins that mediate viral entry and may affect or determine the host range of a virus. The acquisition, exchange, and evolution of such envelope proteins may dramatically affect the success and evolutionary divergence of viruses. In the family Baculoviridae, two very different envelope fusion proteins have been identified. Budded virions of group I

Oliver Y. Lung; Marilyn Cruz-Alvarez; Gary W. Blissard

2003-01-01

85

Direct Metagenomic Detection of Viral Pathogens in Nasal and Fecal Specimens Using an Unbiased High-Throughput Sequencing Approach  

Microsoft Academic Search

With the severe acute respiratory syndrome epidemic of 2003 and renewed attention on avian influenza viral pandemics, new surveillance systems are needed for the earlier detection of emerging infectious diseases. We applied a “next-generation” parallel sequencing platform for viral detection in nasopharyngeal and fecal samples collected during seasonal influenza virus (Flu) infections and norovirus outbreaks from 2005 to 2007 in

Shota Nakamura; Cheng-Song Yang; Naomi Sakon; Mayo Ueda; Takahiro Tougan; Akifumi Yamashita; Naohisa Goto; Kazuo Takahashi; Teruo Yasunaga; Kazuyoshi Ikuta; Tetsuya Mizutani; Yoshiko Okamoto; Michihira Tagami; Ryoji Morita; Norihiro Maeda; Jun Kawai; Yoshihide Hayashizaki; Yoshiyuki Nagai; Toshihiro Horii; Tetsuya Iida; Takaaki Nakaya; Peter Sommer

2009-01-01

86

1918 Influenza virus hemagglutinin (HA) and the viral RNA polymerase complex enhance viral pathogenicity, but only HA induces aberrant host responses in mice.  

PubMed

The 1918 pandemic influenza virus was the most devastating infectious agent in human history, causing fatal pneumonia and an estimated 20 to 50 million deaths worldwide. Previous studies indicated a prominent role of the hemagglutinin (HA) gene in efficient replication and high virulence of the 1918 virus in mice. It is, however, still unclear whether the high replication ability or the 1918 influenza virus HA gene is required for 1918 virus to exhibit high virulence in mice. Here, we examined the biological properties of reassortant viruses between the 1918 virus and a contemporary human H1N1 virus (A/Kawasaki/173/2001 [K173]) in a mouse model. In addition to the 1918 influenza virus HA, we demonstrated the role of the viral RNA replication complex in efficient replication of viruses in mouse lungs, whereas only the HA gene is responsible for lethality in mice. Global gene expression profiling of infected mouse lungs revealed that the 1918 influenza virus HA was sufficient to induce transcriptional changes similar to those induced by the 1918 virus, despite difference in lymphocyte gene expression. Increased expression of genes associated with the acute-phase response and the protein ubiquitination pathway were enriched during infections with the 1918 and 1918HA/K173 viruses, whereas reassortant viruses bearing the 1918 viral RNA polymerase complex induced transcriptional changes similar to those seen with the K173 virus. Taken together, these data suggest that HA and the viral RNA polymerase complex are critical determinants of Spanish influenza pathogenesis, but only HA, and not the viral RNA polymerase complex and NP, is responsible for extreme host responses observed in mice infected with the 1918 influenza virus. PMID:23449804

Watanabe, Tokiko; Tisoncik-Go, Jennifer; Tchitchek, Nicolas; Watanabe, Shinji; Benecke, Arndt G; Katze, Michael G; Kawaoka, Yoshihiro

2013-02-28

87

Ranavirus phylogeny and differentiation based on major capsid protein, DNA polymerase and neurofilament triplet H1-like protein genes.  

PubMed

In this study, we developed new methods for differentiation of ranaviruses based on polymerase chain reaction and restriction enzyme analysis of DNA polymerase and neurofilament triplet H1-like (NF-H1) protein gene. Using these methods, we were able to differentiate the 6 known ranaviruses--Bohle iridovirus (BIV), European catfish virus (ECV), epizootic haematopoietic necrosis virus (EHNV), European sheatfish virus (ESV), frog virus 3 (FV3) and Singapore grouper iridovirus (SGIV)--with 3 less characterised virus isolates: short-finned eel ranavirus (SERV), Rana esculenta virus Italy 282/I02 (REV 282/I02) and pike-perch iridovirus (PPIV). Doctor fish virus (DFV) and guppy virus 6 (GV6) were distinguished as a group from the other viruses. In addition, all 11 isolates were analysed and compared based on nucleotide sequences from 3 different genomic regions: major capsid protein (MCP), DNA polymerase and NF-H1. The partial DNA polymerase gene was sequenced from all analysed viruses. The complete sequence of the MCP and a fragment of the NF-H1 gene were obtained from BIV, ECV, EHNV, ESV, FV3, PPIV, REV 282/I02 and SERV. With the exception of GV6, DFV and SGIV, the sequence analyses showed only a few variations within the analysed viruses. The sequence data suggest that PPIV, REV 282/I02 and SERV are new members of the genus Ranavirus. The methods developed in this study provide tools to differentiate between closely related ranaviruses of different host and geographical origin. PMID:19694168

Holopainen, R; Ohlemeyer, S; Schütze, H; Bergmann, S M; Tapiovaara, H

2009-06-10

88

Role of the Proline-Rich Motif of Bovine Leukemia Virus Transmembrane Protein gp30 in Viral Load and Pathogenicity in Sheep  

PubMed Central

The cytoplasmic tail of bovine leukemia virus (BLV) transmembrane protein gp30 has multiple amino acid motifs that mimic those present in signaling proteins associated with B-cell and T-cell receptors. The proline-rich motif of gp30, PX2PX4–5P, is analogous to the recognition site of Src homology 3 (SH3) domains of signaling molecules. Using site-directed mutagenesis of an infectious molecular clone of BLV, point mutations were introduced which changed three of the prolines of the motif to alanines. The influence of these mutations on the pathogenicity of BLV was studied in sheep which received either (i) plasmid DNA with provirus containing proline-to-alanine mutations (pppBLV), (ii) plasmid DNA with wild-type provirus (wtBLV), or (iii) transfection reagent alone. Although all of the BLV-injected animals seroconverted at approximately the same time, viral loads at later time points were high in five of five of the wtBLV group and two of five of the pppBLV group but low in three of five of the pppBLV group, as determined by semiquantitative PCR. Viral expression was lower in the pppBLV-transfected sheep, as measured by p24 antigen enzyme-linked immunosorbent assay in cultured cells, and serologic titers were lower. Thirty-one months after transfection, four of four wtBLV-transfected sheep had died of leukemia and lymphoma, and all five of the pppBLV-transfected sheep were clinically healthy and had normal peripheral blood lymphocyte counts. These data indicate that the proline-rich motif of gp30 is not required for viral infectivity but is important for high viral load in vivo, suggesting that SH3-mediated gp30 interactions are critical for viral pathogenesis following infection. Absence of interactions with the proline-rich motif may prevent or delay tumorigenesis in sheep.

Reichert, M.; Winnicka, A.; Willems, L.; Kettmann, R.; Cantor, G. H.

2001-01-01

89

Variation in viral shedding patterns between different wild bird species infected experimentally with low-pathogenicity avian influenza viruses that originated from wild birds.  

PubMed

The prevalence of infection with avian influenza (AI) virus varies significantly between taxonomic Orders and even between species within the same Order. The current understanding of AI infection and virus shedding parameters in wild birds is limited and largely based on trials conducted in mallards (Anas platyrhynchos). The objective of the present study was to provide experimental data to examine species-related differences in susceptibility and viral shedding associated with wild bird-origin low-pathogenicity avian influenza (LPAI) viruses in multiple duck species and gulls. Thus mallards, redheads (Aythya americana), wood ducks (Aix sponsa), and laughing gulls (Leucophaeus atricilla) were inoculated experimentally with three wild mallard-origin LPAI viruses representing multiple subtypes. Variation in susceptibility and patterns of viral shedding associated with LPAI virus infection was evident between the duck and gull species. Consistent with the literature, mallards excreted virus predominantly via the gastrointestinal tract. In wood ducks, redheads, and laughing gulls, AI virus was detected more often in oropharyngeal swabs than cloacal swabs. The results of this study suggest that LPAI shedding varies between taxonomically related avian species. Such differences may be important for understanding the potential role of individual species in the transmission and maintenance of LPAI viruses and may have implications for improving sampling strategies for LPAI detection. Additional comparative studies, which include LPAI viruses originating from non-mallard species, are necessary to further characterize these infections in wild avian species other than mallards and provide a mechanism to explain these differences in viral excretion. PMID:21500030

Costa, Taiana P; Brown, Justin D; Howerth, Elizabeth W; Stallknecht, David E

2011-04-01

90

A loop-mediated isothermal amplification method for the detection of members of the genus Ranavirus.  

PubMed

A loop-mediated isothermal amplification (LAMP) method was developed for detection of members of the genus Ranavirus. The optimum reaction mixture contained 2.5 ?L of each inner primer, RV-FIP (20 pmol/?L) and RV-BIP (20 pmol/?L), 0.5 ?L of each outer primer, RV-F3 (10 pmol/?L) and RV-B3 (10 pmol/?L), 1.25 ?L of each loop primer, RV-LF (20 pmol/?L) and RV-LB (20 pmol/?L), 3.5 ?L dNTP mix (10 mM each), 8 ?L MgSO4 (25 mM), 1 ?L of Bst DNA polymerase (8 U/mL, large fragment; New England Biolabs Inc., Beverly, MA, USA), 2.5 ?L 10 × supplied buffer, and 1 ?L of template DNA in a final volume of 25 ?L. The optimum reaction conditions were 63 °C for 60 min. This LAMP method could detect Andrias davidianus iridovirus (ADIV), soft-shelled turtle iridovirus (STIV), and epizootic hematopoietic necrosis virus (EHNV), all of which belong to the genus Ranavirus, but it could not detect other viruses such as koi herpes virus (KHV), channel catfish virus (CCV), infectious spleen and kidney necrosis virus (ISKNV) and white spot syndrome virus (WSSV). The detection limit of the LAMP method was 100 copies of STIV DNA segment, and the sensitivity was 10 times higher than that of the polymerase chain reaction (PCR) assay. The results could be estimated visually by eye when calcein was added. PMID:23665768

Min, Zhang; Hongli, Jing; Lifeng, Zhang; Na, Wang; Shaoqiang, Wu; Xiangmei, Lin

2013-05-12

91

Conventional inactivated bivalent H5/H7 vaccine prevents viral localization in muscles of turkeys infected experimentally with low pathogenic avian influenza and highly pathogenic avian influenza H7N1 isolates  

PubMed Central

Highly pathogenic avian influenza (HPAI) viruses cause viraemia and systemic infections with virus replication in internal organs and muscles; in contrast, low pathogenicity avian influenza (LPAI) viruses produce mild infections with low mortality rates and local virus replication. There is little available information on the ability of LPAI viruses to cause viraemia or on the presence of avian influenza viruses in general in the muscles of infected turkeys. The aim of the present study was to determine the ability of LPAI and HPAI H7N1 viruses to reach muscle tissues following experimental infection and to determine the efficacy of vaccination in preventing viraemia and meat localization. The potential of infective muscle tissue to act as a source of infection for susceptible turkeys by mimicking the practice of swill-feeding was also investigated. The HPAI virus was isolated from blood and muscle tissues of all unvaccinated turkeys; LPAI could be isolated only from blood of one bird and could be detected only by reverse transcriptasepolymerase chain reaction in muscles. In contrast, no viable virus or viral RNA could be detected in muscles of vaccinated/challenged turkeys, indicating that viral localization in muscle tissue is prevented in vaccinated birds.

Toffan, Anna; Beato, Maria Serena; De Nardi, Roberta; Bertoli, Elena; Salviato, Annalisa; Cattoli, Giovanni; Terregino, Calogero; Capua, Ilaria

2008-01-01

92

The Protein Kinase Double-Stranded RNA-Dependent (PKR) Enhances Protection against Disease Cause by a Non-Viral Pathogen  

PubMed Central

PKR is well characterized for its function in antiviral immunity. Using Toxoplasma gondii, we examined if PKR promotes resistance to disease caused by a non-viral pathogen. PKR?/? mice infected with T. gondii exhibited higher parasite load and worsened histopathology in the eye and brain compared to wild-type controls. Susceptibility to toxoplasmosis was not due to defective expression of IFN-?, TNF-?, NOS2 or IL-6 in the retina and brain, differences in IL-10 expression in these organs or to impaired induction of T. gondii-reactive T cells. While macrophages/microglia with defective PKR signaling exhibited unimpaired anti-T. gondii activity in response to IFN-?/TNF-?, these cells were unable to kill the parasite in response to CD40 stimulation. The TRAF6 binding site of CD40, but not the TRAF2,3 binding sites, was required for PKR phosphorylation in response to CD40 ligation in macrophages. TRAF6 co-immunoprecipitated with PKR upon CD40 ligation. TRAF6-PKR interaction appeared to be indirect, since TRAF6 co-immunoprecipitated with TRAF2 and TRAF2 co-immunoprecipitated with PKR, and deficiency of TRAF2 inhibited TRAF6-PKR co-immunoprecipitation as well as PKR phosphorylation induced by CD40 ligation. PKR was required for stimulation of autophagy, accumulation the autophagy molecule LC3 around the parasite, vacuole-lysosomal fusion and killing of T. gondii in CD40-activated macrophages and microglia. Thus, our findings identified PKR as a mediator of anti-microbial activity and promoter of protection against disease caused by a non-viral pathogen, revealed that PKR is activated by CD40 via TRAF6 and TRAF2, and positioned PKR as a link between CD40-TRAF signaling and stimulation of the autophagy pathway.

White, Christine L.; Patel, Krupen; Lamb, Bruce; Sen, Ganes C.; Subauste, Carlos S.

2013-01-01

93

A multiplexed reverse transcriptase PCR assay for identification of viral respiratory pathogens at point-of-care  

SciTech Connect

We have developed a nucleic acid-based assay that is rapid, sensitive, specific, and can be used for the simultaneous detection of 5 common human respiratory pathogens including influenza A, influenza B, parainfluenza type 1 and 3, respiratory syncytial virus, and adenovirus group B, C, and E. Typically, diagnosis on an un-extracted clinical sample can be provided in less than 3 hours, including sample collection, preparation, and processing, as well as data analysis. Such a multiplexed panel would enable rapid broad-spectrum pathogen testing on nasal swabs, and therefore allow implementation of infection control measures, and timely administration of antiviral therapies. This article presents a summary of the assay performance in terms of sensitivity and specificity. Limits of detection are provided for each targeted respiratory pathogen, and result comparisons are performed on clinical samples, our goal being to compare the sensitivity and specificity of the multiplexed assay to the combination of immunofluorescence and shell vial culture currently implemented at the UCDMC hospital. Overall, the use of the multiplexed RT-PCR assay reduced the rate of false negatives by 4% and reduced the rate of false positives by up to 10%. The assay correctly identified 99.3% of the clinical negatives, 97% of adenovirus, 95% of RSV, 92% of influenza B, and 77% of influenza A without any extraction performed on the clinical samples. The data also showed that extraction will be needed for parainfluenza virus, which was only identified correctly 24% of the time on un-extracted samples.

Letant, S E; .Ortiz, J I; Tammero, L; Birch, J M; Derlet, R W; Cohen, S; Manning, D; McBride, M T

2007-04-11

94

Genotyping and Pathogenicity of Viral Hemorrhagic Septicemia Virus from Free-Living Turbot (Psetta maxima) in a Turkish Coastal Area of the Black Sea  

PubMed Central

Viral hemorrhagic septicemia (VHS) is one of the most serious fish viral diseases for cultured rainbow trout (Oncorhynchus mykiss), although VHS virus (VHSV) seems to be ubiquitous among marine fishes. In the present study, VHSV isolation was performed with free-living and cultured turbot (Psetta maxima) in the Trabzon coastal area of the Black Sea to evaluate participation of VHSV in mass mortalities of seed-produced turbot larvae. VHSV was detected in 14 of 66 free-living spawners (positive ratio, 21.2%), 1 of 65 free-living immature fish (1.5%) and 7 of 40 cultured brood stock (17.5%), respectively. Based on a partial glycoprotein gene nucleotide sequence, Turkish VHSV isolates were classified into the class I-e of genotype I and were the most closely related to the GE-1.2 isolate (>98% identity), which was found >20 years ago in Georgia. Thus, it was revealed that Turkish VHSV isolates were not introduced from European countries, it could be an indigenous type of VHSV distributing in the Black Sea environment. In pathogenicity tests, the Turkish isolates did not induce mortality in turbot larvae and rainbow trout fingerlings. Mass mortalities at a rate of approximately 90% occurred in turbot larvae produced by experimental seeding, although VHSV was not detected in any dead fish. Thus, it was concluded that mass mortality in the seed-produced turbot larvae was not caused by VHSV infection.

Nishizawa, Toyohiko; Savas, Hac?; Is?dan, Hakan; Ustundag, Cennet; Iwamoto, Hiroshi; Yoshimizu, Mamoru

2006-01-01

95

A truncated form of Nef selected during pathogenic reversion of simian immunodeficiency virus SIVmac239Deltanef increases viral replication.  

PubMed

The live, attenuated vaccine simian immunodeficiency virus SIVmac239Deltanef efficiently protects rhesus macaques against infection with wild-type SIVmac but occasionally causes CD4(+) T-cell depletion and progression to simian AIDS (SAIDS). Virus recovered from a vaccinated macaque (Rh1490) that progressed to SAIDS had acquired an additional deletion in the nef gene, resulting in a frameshift that restored the original nef open reading frame (R. I. Connor, D. C. Montefiori, J. M. Binley, J. P. Moore, S. Bonhoeffer, A. Gettie, E. A. Fenamore, K. E. Sheridan, D. D. Ho, P. J. Dailey, and P. A. Marx, J. Virol. 72:7501-7509, 1998). Intravenous inoculation of the Rh1490 viral isolate into four naive rhesus macaques induced CD4(+) T-cell depletion and disease in three out of four animals within 2 years, indicating a restoration of virulence. A DNA fragment encompassing the truncated nef gene amplified from the Rh1490 isolate was inserted into the genetic backbone of SIVmac239. The resulting clone, SIVmac239-Delta2nef, expressed a Nef protein of approximately 23 kDa, while the original SIVmac239Deltanef clone expressed a shorter protein of 8 kDa. The revertant form of Nef did not cause downregulation of CD4, CD3, or major histocompatibility complex class I. The infectivity of SIVmac239-Delta2nef was similar to that of SIVmac239Deltanef in single-cycle assays using indicator cell lines. In contrast, SIVmac239-Delta2nef replicated more efficiently than SIVmac239Deltanef in peripheral blood mononuclear cell (PBMC) cultures infected under unstimulated conditions. The p27 Gag antigen levels in SIVmac239-Delta2nef-infected cultures were still lower than those obtained with wild-type SIVmac239, consistent with a partial recovery of Nef function. The transcriptional activity of long terminal repeat (LTR)-luciferase constructs containing the nef deletions did not differ markedly from that of wild-type LTR. Introduction of a premature stop codon within Nef-Delta2 abolished the replicative advantage in PBMCs, demonstrating that the Nef-Delta2 protein, rather than the structure of the U3 region of the LTR, was responsible for the increase in viral replication. Taken together, these results show that SIV with a deletion in the nef gene can revert to virulence and that expression of a form of nef with multiple deletions may contribute to this process by increasing viral replication. PMID:12502842

Chakrabarti, Lisa A; Metzner, Karin J; Ivanovic, Tijana; Cheng, Hua; Louis-Virelizier, Jean; Connor, Ruth I; Cheng-Mayer, Cecilia

2003-01-01

96

Cutting edge: mucosal application of a lyophilized viral vector vaccine confers systemic and protective immunity toward intracellular pathogens.  

PubMed

A major problem of current vaccines is storage stability, often requiring strict maintenance of cold chains. In the course of the eradication of smallpox, a freeze-dried vaccinia virus (Dryvax), which proved to be very stable, was used to overcome this limitation. However, Dryvax needs to be reconstituted before usage and is administered using a bifurcated needle, procedures that pose a number of additional health risks. We report in this study that a stable, lyophilized, modified vaccinia virus Ankara (MVA) vaccine can be directly applied to the nostrils of mice without previous reconstitution. This direct mucosal application induced systemic Ab and T cell responses comparable to those achieved by i.m. administration. Importantly, mucosal application of lyophilized MVA induced long-lasting protective immunity against lethal bacterial and viral challenges. These data clearly demonstrate the potency of a simple needle-free vaccination, combining the advantages of mucosal application with the stability and efficiency of lyophilized MVA. PMID:19234150

Kastenmuller, Wolfgang; Gasteiger, Georg; Stross, Leon; Busch, Dirk H; Drexler, Ingo

2009-03-01

97

Eight-Plex PCR and Liquid-Array Detection of Bacterial and Viral Pathogens in Cerebrospinal Fluid from Patients with Suspected Meningitis?  

PubMed Central

We here report on the development of a novel multiplex PCR with product detection in a Luminex 100 suspension array system. The assay covers the nine most important bacterial and viral pathogens found in Danish meningitis patients. The microorganisms include Neisseria meningitidis, Streptococcus pneumoniae, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Streptococcus agalactiae, herpes simplex virus types 1 and 2, and varicella-zoster virus. The study was based on 1,187 samples, of which 55 were found to be positive by PCR. The assay was found to have an excellent sensitivity and an excellent specificity compared to the results of a “gold standard,” defined by routine laboratory tests, for the two most important pathogens, S. pneumoniae (95 and 99.1%, respectively) and N. meningitidis (100 and 99.7%, respectively). The method provides a valuable supplement to the traditional microscopy and culture of cerebrospinal fluid (CSF) samples in a routine diagnostic setting, and results can be available within 1 workday. The method is suitable for use for the initial screening and identification of nine important microorganisms in CSF samples from patients with suspected meningitis. Compared to microscopy and culture of CSF, this rapid and sensitive method will support physicians with the selection of the appropriate antimicrobial agents and the initiation of timely treatment in the absence of live microorganisms in the CSF.

B?ving, Mette Kusk; Pedersen, Lisbeth N?rum; M?ller, Jens Kj?lseth

2009-01-01

98

Studies on the inactivation of selected viral and bacterial fish pathogens at high pH for waste disposal purposes.  

PubMed

This study investigated the use of alkaline hydrolysis at ambient temperature for inactivation of selected fish pathogens in fish tissues under conditions approximating those that are likely to be found in the aquaculture industry. Infectious salmon anaemia virus (ISAV) and Lactococcus garvieae have been determined in a previous study to be the most resistant virus and bacteria to pH 12 from a wide range of viruses and bacteria tested. They were spiked at high titres into fish extracts that were then treated with 1 m sodium hydroxide (NaOH). Viable L. garvieae was not detected in the treated fish extract after 1 h, and ISAV was not detected after 24-h exposure. Field mortalities of Atlantic salmon, Salmo salar L., caused by infectious pancreatic necrosis virus were treated by alkaline hydrolysis at ambient temperature. The macerated fish mortalities contained a high titre of virus (3.38 × 10? TCID?? g?¹) that was reduced to approximately 2.2 × 10³ TCID?? g?¹ after 24-h exposure to NaOH, and virus was not detected after exposure for 48 h. The results suggest that alkaline hydrolysis at ambient temperature has potential as a biosecure treatment method for fish by-products containing fish pathogens. PMID:22092262

Dixon, P F; Algoët, M; Bayley, A; Dodge, M; Joiner, C; Roberts, E

2011-11-17

99

Loss of Anti-Viral Immunity by Infection with a Virus Encoding a Cross-Reactive Pathogenic Epitope  

PubMed Central

T cell cross-reactivity between different strains of the same virus, between different members of the same virus group, and even between unrelated viruses is a common occurrence. We questioned here how an intervening infection with a virus containing a sub-dominant cross-reactive T cell epitope would affect protective immunity to a previously encountered virus. Pichinde virus (PV) and lymphocytic choriomeningitis virus (LCMV) encode subdominant cross-reactive NP205–212 CD8 T cell epitopes sharing 6 of 8 amino acids, differing only in the MHC anchoring regions. These pMHC epitopes induce cross-reactive but non-identical T cell receptor (TCR) repertoires, and structural studies showed that the differing anchoring amino acids altered the conformation of the MHC landscape presented to the TCR. PV-immune mice receiving an intervening infection with wild type but not NP205-mutant LCMV developed severe immunopathology in the form of acute fatty necrosis on re-challenge with PV, and this pathology could be predicted by the ratio of NP205-specific to the normally immunodominant PV NP38–45 -specific T cells. Thus, cross-reactive epitopes can exert pathogenic properties that compromise protective immunity by impairing more protective T cell responses.

Chen, Alex T.; Cornberg, Markus; Gras, Stephanie; Guillonneau, Carole; Rossjohn, Jamie; Trees, Andrew; Emonet, Sebastien; de la Torre, Juan C.; Welsh, Raymond M.; Selin, Liisa K.

2012-01-01

100

Optimal testing of the live organ donor for blood-borne viral pathogens: the report of a consensus conference.  

PubMed

In 2011, live donor transmission events involving Human Immunodeficiency Virus (HIV) and Hepatitis C virus (HCV) prompted consideration of changing the process of live donor testing and evaluation in the United States. Following CDC recommendations for screening all live donors with nucleic acid testing for HIV, HCV and Hepatitis B (HBV), a consensus conference was convened to evaluate this recommendation. Workgroups focused on determining whether there was an evidence based rationale for identifying live donors at increased risk for HIV, HBV and HCV, testing options and timing for diagnosing these infections in potential donors and consent issues specific to potential increased risk donor utilization. Strategies for donor assessment were proposed. Based on review of the limited available evidence as well as guidance documents and policies currently in place in the United States and other countries, the conference participants recommended that HIV, HBV and HCV NAT should not be required for live donor evaluation; the optimal timing of live donor testing for these blood borne pathogens has not been determined. PMID:23601095

Blumberg, E A; Ison, M G; Pruett, T L; Segev, D L

2013-04-19

101

Rescue of Foot-and-Mouth Disease Viruses That Are Pathogenic for Cattle from Preserved Viral RNA Samples  

PubMed Central

Background Foot and mouth disease is an economically important disease of cloven-hoofed animals including cattle, sheep and pigs. It is caused by a picornavirus, foot-and-mouth disease virus (FMDV), which has a positive sense RNA genome which, when introduced into cells, can initiate virus replication. Principal Findings A system has been developed to rescue infectious FMDV from RNA preparations generated from clinical samples obtained under experimental conditions and then applied to samples collected in the “field”. Clinical samples from suspect cases of foot-and-mouth disease (FMD) were obtained from within Pakistan and Afghanistan. The samples were treated to preserve the RNA and then transported to National Veterinary Institute, Lindholm, Denmark. Following RNA extraction, FMDV RNA was quantified by real-time RT-PCR and samples containing significant levels of FMDV RNA were introduced into susceptible cells using electroporation. Progeny viruses were amplified in primary bovine thyroid cells and characterized using antigen ELISA and also by RT-PCR plus sequencing. FMD viruses of three different serotypes and multiple lineages have been successfully rescued from the RNA samples. Two of the rescued viruses (of serotype O and Asia 1) were inoculated into bull calves under high containment conditions. Acute clinical disease was observed in each case which spread rapidly from the inoculated calves to in-contact animals. Thus the rescued viruses were highly pathogenic. The availability of the rescued viruses enabled serotyping by antigen ELISA and facilitated genome sequencing. Conclusions The procedure described here should improve the characterization of FMDVs circulating in countries where the disease is endemic and thus enhance disease control globally.

Belsham, Graham J.; Jamal, Syed M.; Tj?rneh?j, Kirsten; B?tner, Anette

2011-01-01

102

A member of the cathelicidin family of antimicrobial peptides is produced in the upper airway of the chinchilla and its mRNA expression is altered by common viral and bacterial co-pathogens of otitis media  

Microsoft Academic Search

Cationic antimicrobial peptides (AMPs), a component of the innate immune system, play a major role in defense of mucosal surfaces against a wide spectrum of microorganisms such as viral and bacterial co-pathogens of the polymicrobial disease otitis media (OM). To further understand the role of AMPs in OM, we cloned a cDNA encoding a cathelicidin homolog (cCRAMP) from upper respiratory

Glen McGillivary; William C. Ray; Charles L. Bevins; Robert S. Munson Jr.; Lauren O. Bakaletz

2007-01-01

103

Combined administration in a single injection of a feline multivalent modified live vaccine against FHV, FCV, and FPLV together with a recombinant FeLV vaccine is both safe and efficacious for all four major feline viral pathogens.  

PubMed

Nobivac Tricat, a lyophilised trivalent modified live attenuated vaccine is routinely used to protect cats against three commonly diagnosed feline viral pathogens namely herpesvirus, calicivirus and panleukopenia virus. The recognition of feline leukaemia virus (FeLV) as an important viral pathogen has prompted the development of an efficacious liquid recombinant subunit FeLV vaccine (p45 envelope protein). Lyophilised Tricat vaccine was dissolved in the liquid FeLV vaccine and no detectable deleterious effect on the titre of any of the live virus components was observed after 2h incubation. In vivo studies where the vaccines were mixed in the same syringe prior to inoculation showed no alteration to the safety profile assessed by repeat and overdose studies. Serological comparisons of the modified live viral antibody titres showed no evidence of reduced responses following administration of the mixed products. Challenge studies using pathogenic herpesvirus and FeLV revealed no difference in the degree of clinical protection. This paper shows that neither safety nor efficacy is adversely affected as a result of mixing the two vaccines. PMID:18448375

Kanellos, Theo; Sutton, David J; Salisbury, Claire F; Chalmers, William Stuart K

2008-05-02

104

Viral determinants of simian immunodeficiency virus (SIV) virulence in rhesus macaques assessed by using attenuated and pathogenic molecular clones of SIVmac.  

PubMed Central

To identify viral determinants of simian immunodeficiency virus (SIV) virulence, two pairs of reciprocal recombinants constructed from a pathogenic (SIVmac239) and a nonpathogenic (SIVmac1A11) molecular clone of SIV were tested in rhesus macaques. A large 6.2-kb fragment containing gag, pol, env, and the regulatory genes from each of the cloned (parental) viruses was exchanged to produce one pair of recombinant viruses (designated SIVmac1A11/239gag-env/1A11 and SIVmac239/1A11gag-env/239 to indicate the genetic origins of the 5'/internal/3' regions, respectively, of the virus). A smaller 1.4-kb fragment containing the external env domain of each of the parental viruses was exchanged to create the second pair (SIVmac1A11/239env/1A11 and SIVmac239/1A11env/239) of recombinant viruses. Each of the two parental and four recombinant viruses was inoculated intravenously into four rhesus macaques, and all 24 animals were viremic by 4 weeks postinoculation (p.i.). Virus could not be isolated from peripheral blood mononuclear cells (PBMC) of any animals infected with SIVmac1A11 after 6 weeks p.i. but was consistently isolated from all macaques inoculated with SIVmac239 for 92 weeks p.i. Virus isolation was variable from animals infected with recombinant viruses; SIVmac1A11/239gag-env/1A11 and SIVmac239/1A11env/239 were isolated most frequently. Animals inoculated with SIVmac239 had 10 to 100 times more virus-infected PBMC than those infected with recombinant viruses. Three animals infected with SIVmac239 died with simian AIDS (SAIDS) during the 2-year observation period after inoculation, and the fourth SIVmac239-infected animal had clinical signs of SAIDS. Two animals infected with recombinant viruses died with SAIDS; one was infected with SIVmac239/1A11gag-env/239, and the other was infected with SIVmac1A11/239gag-env/1A11. The remaining 18 macaques remained healthy by 2 years p.i., and 13 were aviremic. One year after inoculation, peripheral lymph nodes of some of these healthy, aviremic animals harbored infected cells. All animals seroconverted within the first few weeks of infection, and the magnitude of antibody response to SIV was proportional to the levels and duration of viremia. Virus-suppressive PBMC were detected within 2 to 4 weeks p.i. in all animals but tended to decline as viremia disappeared. There was no association of levels of cell-mediated virus-suppressive activity and either virus load or disease progression. Taken together, these results indicate that differences in more than one region of the viral genome are responsible for the lack of virulence of SIVmac1A11.

Marthas, M L; Ramos, R A; Lohman, B L; Van Rompay, K K; Unger, R E; Miller, C J; Banapour, B; Pedersen, N C; Luciw, P A

1993-01-01

105

Efficacy of an inactivated and a fowlpox-vectored vaccine in Muscovy ducks against an Asian H5N1 highly pathogenic avian influenza viral challenge.  

PubMed

The efficacy of an inactivated vaccine containing the Eurasian isolate A/chicken/Italy/22A/98 H5N9 (H5N9-It) was compared with that of the fowlpox-vectored TROVACTM-AIV H5 (rFP-AIV-H5) vaccine against an H5N1 highly pathogenic avian influenza challenge. Five-week-old Muscovy ducks were vaccinated with either H5N9-It (0.5 ml) or rFP-AIV-H5 (5 log10 50% tissue culture infectious dose (TCID50)/dose), followed by a boost at 7 wk of age with the same vaccine (1.0 ml of H5N9-It or 5 log10 TCID50/dose rFP-AIV-H5), and a challenge at 9 wk of age with 10(7) egg infectious dose (lethality 50%) of A/crested eagle/ Belgium/01/2004 (H5N1). All unvaccinated challenged birds showed severe nervous signs (loss of balance, torticollis) starting 7 days postinfection (dpi). None of the vaccinated ducks showed these nervous signs. Shedding was measured in oropharyngeal and cloacal swabs, sampled from 3 to 19 dpi by titration in chicken embryo fibroblasts and by real-time reverse transcription-polymerase chain reaction. Virus shedding was significantly higher in oropharyngeal compared to cloacal swabs. Both vaccines reduced the percentage of positive swabs and the viral load in the swabs, but the reduction was higher with the H5N9-It vaccine. The inactivated vaccine induced hemagglutination inhibition (HI) titers (5.4 log2) that were boosted after the second administration (7.5 log2). rFP-AIV-H5-induced HI titers were lower (3 log2 only after the second administration), most probably because the fowlpox vector does not replicate in ducks. Altogether, these results indicate that significant protection from clinical signs and reduction in virus shedding may be achieved in ducks with conventional inactivated or fowlpox-vectored vaccine as compared with nonvaccinated challenged control birds. PMID:17494576

Steensels, M; Van Borm, S; Lambrecht, B; De Vriese, J; Le Gros, F X; Bublot, M; van den Berg, T

2007-03-01

106

Detection of 11 Common Viral and Bacterial Pathogens Causing Community-Acquired Pneumonia or Sepsis in Asymptomatic Patients by Using a Multiplex Reverse Transcription-PCR Assay with Manual (Enzyme Hybridization) or Automated (Electronic Microarray) Detection?  

PubMed Central

Community-acquired pneumonia (CAP) and sepsis are important causes of morbidity and mortality. We describe the development of two molecular assays for the detection of 11 common viral and bacterial agents of CAP and sepsis: influenza virus A, influenza virus B, respiratory syncytial virus A (RSV A), RSV B, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, Legionella micdadei, Bordetella pertussis, Staphylococcus aureus, and Streptococcus pneumoniae. Further, we report the prevalence of carriage of these pathogens in respiratory, skin, and serum specimens from 243 asymptomatic children and adults. The detection of pathogens was done using both a manual enzyme hybridization assay and an automated electronic microarray following reverse transcription and PCR amplification. The analytical sensitivities ranged between 0.01 and 100 50% tissue culture infective doses, cells, or CFU per ml for both detection methods. Analytical specificity testing demonstrated no significant cross-reactivity among 19 other common respiratory organisms. One hundred spiked “surrogate” clinical specimens were all correctly identified with 100% specificity (95% confidence interval, 100%). Overall, 28 (21.7%) of 129 nasopharyngeal specimens, 11 of 100 skin specimens, and 2 of 100 serum specimens from asymptomatic subjects tested positive for one or more pathogens, with S. pneumoniae and S. aureus giving 89% of the positive results. Our data suggest that asymptomatic carriage makes the use of molecular assays problematic for the detection of S. pneumoniae or S. aureus in upper respiratory tract secretions; however, the specimens tested showed virtually no carriage of the other nine viral and bacterial pathogens, and the detection of these pathogens should not be a significant diagnostic problem. In addition, slightly less sensitive molecular assays may have better correlation with clinical disease in the case of CAP.

Kumar, Swati; Wang, Lihua; Fan, Jiang; Kraft, Andrea; Bose, Michael E.; Tiwari, Sagarika; Van Dyke, Meredith; Haigis, Robert; Luo, Tingquo; Ghosh, Madhushree; Tang, Huong; Haghnia, Marjan; Mather, Elizabeth L.; Weisburg, William G.; Henrickson, Kelly J.

2008-01-01

107

A member of the cathelicidin family of antimicrobial peptides is produced in the upper airway of the chinchilla and its mRNA expression is altered by common viral and bacterial co-pathogens of otitis media  

PubMed Central

Cationic antimicrobial peptides (AMPs), a component of the innate immune system, play a major role in defense of mucosal surfaces against a wide spectrum of microorganisms such as viral and bacterial co-pathogens of the polymicrobial disease otitis media (OM). To further understand the role of AMPs in OM, we cloned a cDNA encoding a cathelicidin homolog (cCRAMP) from upper respiratory tract (URT) mucosae of the chinchilla, the predominant host used to model experimental OM. Recombinant cCRAMP exhibited alpha-helical secondary structure and killed the three main bacterial pathogens of OM. In situ hybridization showed cCRAMP mRNA production in epithelium of the chinchilla Eustachian tube and RT-PCR was used to amplify cCRAMP mRNA from several other tissues of the chinchilla URT. Quantitative RT-PCR analysis of chinchilla middle ear epithelial cells (CMEEs) incubated with either viral (influenza A virus, adenovirus, or RSV) or bacterial (nontypeable H. influenzae, M. catarrhalis, or S. pneumoniae) pathogens associated with OM demonstrated distinct microbe-specific patterns of altered expression. Collectively, these data showed that viruses and bacteria modulate AMP messages in the URT, which likely contributes to the disease course of OM.

McGillivary, Glen; Ray, William C.; Bevins, Charles L.; Munson, Robert S.; Bakaletz, Lauren O.

2007-01-01

108

Role of complement and antibodies in controlling infection with pathogenic simian immunodeficiency virus (SIV) in macaques vaccinated with replication-deficient viral vectors  

Microsoft Academic Search

BACKGROUND: We investigated the interplay between complement and antibodies upon priming with single-cycle replicating viral vectors (SCIV) encoding SIV antigens combined with Adeno5-SIV or SCIV pseudotyped with murine leukemia virus envelope boosting strategies. The vaccine was applied via spray-immunization to the tonsils of rhesus macaques and compared with systemic regimens. RESULTS: Independent of the application regimen or route, viral loads

Barbara Falkensammer; Barbara Rubner; Alexander Hiltgartner; Doris Wilflingseder; Christiane Stahl Hennig; Seraphin Kuate; Klaus Überla; Stephen Norley; Alexander Strasak; Paul Racz; Heribert Stoiber

2009-01-01

109

Thymic pathogenicity of an HIV-1 envelope is associated with increased CXCR4 binding efficiency and V5-gp41-dependent activity, but not V1/V2-associated CD4 binding efficiency and viral entry  

SciTech Connect

We previously described a thymus-tropic HIV-1 envelope (R3A Env) from a rapid progressor obtained at the time of transmission. An HIV-1 molecular recombinant with the R3A Env supported extensive replication and pathogenesis in the thymus and did not require Nef. Another Env from the same patient did not display the same thymus-tropic pathogenesis (R3B Env). Here, we show that relative to R3B Env, R3A Env enhances viral entry of T cells, increases fusion-induced cytopathicity, and shows elevated binding efficiency for both CD4 and CXCR4, but not CCR5, in vitro. We created chimeric envelopes to determine the region(s) responsible for each in vitro phenotype and for thymic pathogenesis. Surprisingly, while V1/V2 contributed to enhanced viral entry, CD4 binding efficiency, and cytopathicity in vitro, it made no contribution to thymic pathogenesis. Rather, CXCR4 binding efficiency and V5-gp41-associated activity appear to independently contribute to thymic pathogenesis of the R3A Env. These data highlight the contribution of unique HIV pathogenic factors in the thymic microenvironment and suggest that novel mechanisms may be involved in Env pathogenic activity in vivo.

Meissner, Eric G. [Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599 (United States); Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599 (United States); Coffield, Vernon M. [Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599 (United States); Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599 (United States); Su Lishan [Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599 (United States) and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599 (United States)]. E-mail: lsu@med.unc.edu

2005-06-05

110

Environmental Factors Influencing Human Viral Pathogens and Their Potential Indicator Organisms in the Blue Mussel, Mytilus edulis: the First Scandinavian Report  

Microsoft Academic Search

This study was carried out in order to investigate human enteric virus contaminants in mussels from three sites on the west coast of Sweden, representing a gradient of anthropogenic influence. Mussels were sampled monthly during the period from February 2000 to July 2001 and analyzed for adeno-, entero-, Norwalk-like, and hepatitis A viruses as well as the potential viral indicator

Bodil E. Hernroth; Ann-Christine Conden-Hansson; Ann-Sofi Rehnstam-Holm; Rosina Girones; Annika K. Allard

2002-01-01

111

Respiratory Viruses Augment the Adhesion of Bacterial Pathogens to Respiratory Epithelium in a Viral Species and Cell Type-Dependent Manner  

Microsoft Academic Search

Secondary bacterial infections often complicate respiratory viral infections, but the mechanisms whereby viruses predispose to bacterial disease are not completely understood. We determined the effects of infection with respiratory syncytial virus (RSV), human parainfluenza virus 3 (HPIV-3), and influenza virus on the abilities of nontypeable Haemophilus influenzae and Streptococcus pneumoniae to adhere to respiratory epithelial cells and how these viruses

Vasanthi Avadhanula; Carina A. Rodriguez; John P. DeVincenzo; Yan Wang; Richard J. Webby; Glen C. Ulett; Elisabeth E. Adderson

2006-01-01

112

Bovine viral diarrhea viruses  

Technology Transfer Automated Retrieval System (TEKTRAN)

Infections with bovine viral diarrhea viruses (BVDV) result in significant economic losses for beef and dairy producers worldwide. BVDV is actually an umbrella term for two species of viruses, BVDV1 and BVDV2, within the Pestivirus genus of the Flavivirus family. While denoted as a bovine pathogen...

113

Detection of Viral Pathogens by Reverse Transcriptase PCR and of Microbial Indicators by Standard Methods in the Canals of the Florida Keys  

Microsoft Academic Search

In order to assess the microbial water quality in canal waters throughout the Florida Keys, a survey was conducted to determine the concentration of microbial fecal indicators and the presence of human pathogenic microorganisms. A total of 19 sites, including 17 canal sites and 2 nearshore water sites, were assayed for total coliforms, fecal coliforms, Escherichia coli, Clostridium perfringens, enterococci,

DALE W. GRIFFIN; CHARLES J. GIBSON; ERIN K. LIPP; KELLEY RILEY; JOHN H. PAUL; JOAN B. ROSE

1999-01-01

114

Serial passage of a street rabies virus in mouse neuroblastoma cells resulted in attenuation: potential role of the additional N-glycosylation of a viral glycoprotein in the reduced pathogenicity of street rabies virus.  

PubMed

Street rabies viruses are field isolates known to be highly neurotropic. However, the viral elements related to their pathogenicity have yet to be identified at the nucleotide or amino acid level. Here, through 30 passages in mouse neuroblastoma NA cells, we have established an attenuated variant of street rabies virus strain 1088, originating from a rabid woodchuck followed by 2 passages in the brains of suckling mice. The variant, 1088-N30, was well adapted to NA cells and highly attenuated in adult mice after intramuscular (i.m.) but not intracerebral (i.c.) inoculations. 1088-N30 had seven nucleotide substitutions, and the R196S mutation of the G protein led to an additional N-glycosylation. Street viruses usually possess one or two N-glycosylation sites on the G protein, 1088 has two, while an additional N-glycosylation site is observed in laboratory-adapted strains. We also established a cloned variant 1088-N4#14 by limiting dilution. Apart from the R196S mutation, 1088-N4#14 possessed only one amino acid substitution in the P protein, which is found in several field isolates. 1088-N4#14 also efficiently replicated in NA cells and was attenuated in adult mice after i.m. inoculations, although it was more pathogenic than 1088-N30. The spread of 1088-N30 in the brain was highly restricted after i.m. inoculations, although the pattern of 1088-N4#14's spread was intermediate between that of the parental 1088 and 1088-N30. Meanwhile, both variants strongly induced humoral immune responses in mice compared to 1088. Our results indicate that the additional N-glycosylation is likely related to the reduced pathogenicity. Taken together, we propose that the number of N-glycosylation sites in the G protein is one of the determinants of the pathogenicity of street rabies viruses. PMID:22248643

Yamada, Kentaro; Park, Chun-Ho; Noguchi, Kazuko; Kojima, Daisuke; Kubo, Tatsuya; Komiya, Naoyuki; Matsumoto, Takashi; Mitui, Marcelo Takahiro; Ahmed, Kamruddin; Morimoto, Kinjiro; Inoue, Satoshi; Nishizono, Akira

2012-01-11

115

Genomic Polymorphism of the Pandemic A (H1N1) Influenza Viruses Correlates with Viral Replication, Virulence, and Pathogenicity In Vitro and In Vivo  

Microsoft Academic Search

The novel pandemic A (H1N1) virus was first identified in Mexico in April 2009 and quickly spread worldwide. Like all influenzas, the H1N1 strain-specific properties of replication, virulence, and pathogenicity are a result of the particular genomic sequence and concerted expression of multiple genes. Thus, specific mutations may support increased virulence and may be useful as biomarkers of potential threat

Lili Xu; Linlin Bao; Jianfang Zhou; Dayan Wang; Wei Deng; Qi Lv; Yila Ma; Fengdi Li; Huihui Sun; Lingjun Zhan; Hua Zhu; Chunmei Ma; Yuelong Shu; Chuan Qin

2011-01-01

116

A serologic assessment of exposure to viral pathogens and Leptospira in an urban raccoon (Procyon lotor) population inhabiting a large zoological park.  

PubMed

In urban environments, raccoons (Procyon lotor) may act as reservoirs for an array of pathogenic organisms, presenting spillover risks for human, domestic animal, and captive (zoo) animal populations. Over 5 yr, 159 raccoons from a high-density raccoon population in St. Louis, Missouri (USA), were surveyed for exposure to canine distemper virus (CDV), canine adenovirus 1 (CAV-1); feline parvovirus (FPV; =feline panleukopenia), and several serovars of Leptospira interrogans. Exposure to each of the viruses and two Leptospira serovars (grippotyphosa and icterohemorrhagiae) was detected (prevalence of CDV = 54.1%; FPV = 49.7%; CAV-1 = 6.9%; L. interrogans icterohemorrhagiae = 8.9%; L. interrogans grippotyphosa = 6.3%). Eighty percent of raccoons showed evidence of exposure to at least one of the five primary pathogens, and 39% were positive for multiple species. Among the viruses, there was a significant co-occurrence of CDV and CAV-1. Longitudinal data on a subset of animals revealed that among individuals who were diagnosed as seropositive on first capture, 33-100% became seronegative for the pathogen of interest when reexamined at a later date. Thus, free-ranging urban raccoons have been exposed to multiple infectious agents, some of which may pose risks to humans and to nonvaccinated domestic and captive animal populations. PMID:17469271

Junge, Randall E; Bauman, Karen; King, Melanie; Gompper, Matthew E

2007-03-01

117

Serologic survey for selected viral pathogens in free-ranging endangered European mink (Mustela lutreola) and other mustelids from south-western France.  

PubMed

To investigate the possible role of selected pathogens in the decline of endangered European mink (Mustela lutreola) populations and the potential for these pathogens to affect mink survival, a serologic survey was conducted using serum samples collected from March 1996 to March 2003 in eight departments of south-western France. In total, 481 free-ranging individuals of five mustelid species (including the European mink) were tested. Sympatric mustelids can serve as sentinels to determine the presence of antibodies to viruses in the study area that could potentially infect mink. Antibodies to Canine distemper virus (CDV) were detected in all species; 9% of 127 European mink, 20% of 210 polecats (Mustela putorius), 5% of 112 American mink (Mustela vison), 33% of 21 stone marten (Martes foina) and 5% of 20 pine marten (Martes martes). Antibody prevalence was significantly higher in stone marten and polecats, possibly because their ranges overlap more closely with that of domestic species than that of the other species tested. Antibodies to Canine adenovirus were detected in all species but the pine marten; antibody prevalence estimates ranging from 2% to 10%. Antibodies to canine parainfluenza virus were detected in 1% of European mink, 1% of American mink and 5% of tested polecats but were not detected in Martes species. Antibodies to Rabies virus (RV) were detected in three animals, possibly because of interspecies transmission of bat lyssaviruses as the sampling area is considered to be free of RV, or to a lack of test specificity, as antibody titers were low. The high antibody prevalence to potentially lethal CDV suggests that this pathogen could have significant effects on the free-ranging populations and has implications for the conservation efforts for the endangered European mink. PMID:18957635

Philippa, Joost; Fournier-Chambrillon, Christine; Fournier, Pascal; Schaftenaar, Willem; van de Bildt, Marco; van Herweijnen, Rob; Kuiken, Thijs; Liabeuf, Marie; Ditcharry, Sébastien; Joubert, Laurent; Bégnier, Michel; Osterhaus, Ab

2008-10-01

118

PA from an H5N1 highly pathogenic avian influenza virus activates viral transcription and replication and induces apoptosis and interferon expression at an early stage of infection  

PubMed Central

Background Although gene exchange is not likely to occur freely, reassortment between the H5N1 highly pathogenic avian influenza virus (HPAIV) and currently circulating human viruses is a serious concern. The PA polymerase subunit of H5N1 HPAIV was recently reported to activate the influenza replicon activity. Methods The replicon activities of PR8 and WSN strains (H1N1) of influenza containing PA from HPAIV A/Cambodia/P0322095/2005 (H5N1) and the activity of the chimeric RNA polymerase were analyzed. A reassortant WSN virus containing the H5N1 Cambodia PA (C-PA) was then reconstituted and its growth in cells and pathogenicity in mice examined. The interferon promoter, TUNEL, and caspase 3, 8, and 9 activities of C-PA-infected cells were compared with those of WSN-infected cells. Results The activity of the chimeric RNA polymerase was slightly higher than that of WSN, and C-PA replicated better than WSN in cells. However, the multi-step growth of C-PA and its pathogenicity in mice were lower than those of WSN. The interferon promoter, TUNEL, and caspase 3, 8, and 9 activities were strongly induced in early infection in C-PA-infected cells but not in WSN-infected cells. Conclusions Apoptosis and interferon were strongly induced early in C-PA infection, which protected the uninfected cells from expansion of viral infection. In this case, these classical host-virus interactions contributed to the attenuation of this strongly replicating virus.

2012-01-01

119

Complement and Viral Pathogenesis  

PubMed Central

The complement system functions as an immune surveillance system that rapidly responds to infection. Activation of the complement system by specific recognition pathways triggers a protease cascade, generating cleavage products that function to eliminate pathogens, regulate inflammatory responses, and shape adaptive immune responses. However, when dysregulated, these powerful functions can become destructive and the complement system has been implicated as a pathogenic effector in numerous diseases, including infectious diseases. This review highlights recent discoveries that have identified critical roles for the complement system in the pathogenesis of viral infection.

Stoermer, Kristina A.; Morrison, Thomas E.

2011-01-01

120

Selected nosocomial viral infections.  

PubMed

A nosocomial viral infection is defined as a viral infection the onset of which occurs when the patient has been hospitalized longer than the incubation period of the virus. Viruses account for about 5% of all nosocomial infections. Viral cross-infection is most common in infants and children but also occurs in other groups, including the elderly, institutionalized persons of all ages, immunocompromised hosts, and patients with underlying chronic pulmonary, renal, or cardiac disease. These infections are associated with extended length of hospital stay and considerable morbidity and mortality. The spectrum of nosocomial viruses is wide and includes blood-borne, respiratory tract, and enteric pathogens, among others. This review will discuss the clinical characteristics, transmission, and control of the common nosocomial respiratory viruses: respiratory syncytial virus, varicella zoster virus, influenza virus, adenovirus, parainfluenza, and rubeola. PMID:8449764

Wright, S A; Bieluch, V M

121

Viral evolution and challenges in the development of HIV vaccines  

Microsoft Academic Search

Potent virus-specific cytotoxic T lymphocyte (CTL) responses elicited by candidate AIDS vaccines have been shown to provide short-term control of viral replication following pathogenic viral challenges in rhesus monkeys. We have recently shown that vaccines that control rather than prevent immunodeficiency virus infections are still subject to immune escape. In particular, viral mutations can develop that result in viral escape

Dan H Barouch; Norman L Letvin

2002-01-01

122

Pathogen-derived resistance using a viral nucleocapsid gene confers only partial non-durable protection in peanut against peanut bud necrosis virus.  

PubMed

Genetic engineering of peanut (Arachis hypogaea L.) using the gene encoding for the nucleocapsid protein (N gene) of peanut bud necrosis virus (PBNV; genus Tospovirus, family Bunyaviridae) was used to impart resistance to bud necrosis disease in peanut (PBND), a disease for which no durable resistance is available in the existing germplasm. Over 200 transgenic lines of peanut var. JL 24 were developed for which integration and expression of the transgenes was confirmed by PCR, Southern hybridization, RT-PCR and western blot analysis. The T(1) and T(2) generation transgenic plants were assayed through virus challenge in the greenhouse by using mechanical sap inoculation at 1:100 and 1:50 dilutions of PBNV, and they showed varying levels of disease incidence and intensity. Greenhouse and field evaluation with T(2) generation plants indicated somewhat superior performance of the three transgenic events that showed considerable reduction in disease incidence. However, only one of these events showed over 75 % reduction in disease incidence when compared to the untransformed control, indicating partial and non-durable resistance to PBND using the viral N-gene. PMID:23011312

Rao, S Chander; Bhatnagar-Mathur, P; Kumar, P Lava; Reddy, A Sudarshan; Sharma, Kiran K

2012-09-26

123

Serological survey of selected canine viral pathogens and zoonoses in grizzly bears (Ursus arctos horribilis) and black bears (Ursus americanus) from Alaska.  

PubMed

Between 1988 and 1991, 644 serum samples were collected from 480 grizzly bears (Ursus arctos horribilis) and 40 black bears (Ursus americanus) from Alaska, United States of America, and were tested for selected canine viral infections and zoonoses. Antibody prevalence in grizzly bears was 0% for parvovirus, 8.3% (40/480) for distemper, 14% (68/480) for infectious hepatitis, 16.5% (79/480) for brucellosis, 19% (93/480) for tularaemia and 47% (225/478) for trichinellosis. In black bears, prevalence ranged from 0% for distemper and parvovirus to 27.5% for trichinellosis and 32% for tularaemia. Antibody prevalence for brucellosis (2.5%) and tularaemia (32%) were identical for grizzly bears and black bears from the geographical area of interior Alaska. Links between differences in prevalence and the origin of the grizzly bears were observed. Antibodies to canine distemper virus and infectious hepatitis virus were mainly detected in grizzly bears from Kodiak Island and the Alaskan Peninsula. Brucellosis antibodies were prevalent in grizzly bears from western and northern Alaska, whereas tularaemia antibodies were detected in grizzly bears from interior Alaska and the Arctic. There was a strong gradient for antibodies to Trichinella spp. from southern to northern Alaska. For most diseases, antibody prevalence increased with age. However, for several infections, no antibodies were detected in grizzly bears aged from 0 to 2 years, in contrast to the presence of those infections in black bears. Grizzly bears served as excellent sentinels for surveillance of zoonotic infections in wildlife in Alaska. PMID:9850547

Chomel, B B; Kasten, R W; Chappuis, G; Soulier, M; Kikuchi, Y

1998-12-01

124

Highly pathogenic H5N1 influenza A virus strains provoke heterogeneous IFN-?/? responses that distinctively affect viral propagation in human cells.  

PubMed

The fatal transmissions of highly pathogenic avian influenza A viruses (IAV) of the H5N1 subtype to humans and high titer replication in the respiratory tract indicate that these pathogens can overcome the bird-to-human species barrier. While type I interferons (IFN-?/?) are well described to contribute to the species barrier of many zoonotic viruses, current data to the role of these antiviral cytokines during human H5N1 IAV infections is limited and contradictory. We hypothesized an important role for the IFN system in limiting productive infection of avian H5N1 strains in human cells. Hence, we examined IFN-?/? gene activation by different avian and human H5N1 isolates, if the IFN-?/? response restricts H5N1 growth and whether the different strains were equally capable to regulate the IFN-?/? system via their IFN-antagonistic NS1 proteins. Two human H5N1 isolates and a seasonal H3N2 strain propagated efficiently in human respiratory cells and induced little IFN-?, whereas three purely avian H5N1 strains were attenuated for replication and provoked higher IFN secretion. Replication of avian viruses was significantly enhanced on interferon-deficient cells, and exogenous IFN potently limited the growth of all strains in human cells. Moreover, IFN-?/? activation by all strains depended on retinoic acid-inducible gene I excluding principal differences in receptor activation between the different viruses. Interestingly, all H5N1 NS1 proteins suppressed IFN-?/? induction comparably well to the NS1 of seasonal IAV. Thus, our study shows that H5N1 strains are heterogeneous in their capacity to activate human cells in an NS1-independent manner. Our findings also suggest that H5N1 viruses need to acquire adaptive changes to circumvent strong IFN-?/? activation in human host cells. Since no single amino acid polymorphism could be associated with a respective high- or low induction phenotype we propose that the necessary adaptations to overcome the human IFN-?/? barrier involve mutations in multiple H5N1 genes. PMID:23451066

Matthaei, Markus; Budt, Matthias; Wolff, Thorsten

2013-02-25

125

Metagenomic Detection of Viral Pathogens in Spanish Honeybees: Co-Infection by Aphid Lethal Paralysis, Israel Acute Paralysis and Lake Sinai Viruses  

PubMed Central

The situation in Europe concerning honeybees has in recent years become increasingly aggravated with steady decline in populations and/or catastrophic winter losses. This has largely been attributed to the occurrence of a variety of known and “unknown”, emerging novel diseases. Previous studies have demonstrated that colonies often can harbour more than one pathogen, making identification of etiological agents with classical methods difficult. By employing an unbiased metagenomic approach, which allows the detection of both unexpected and previously unknown infectious agents, the detection of three viruses, Aphid Lethal Paralysis Virus (ALPV), Israel Acute Paralysis Virus (IAPV), and Lake Sinai Virus (LSV), in honeybees from Spain is reported in this article. The existence of a subgroup of ALPV with the ability to infect bees was only recently reported and this is the first identification of such a strain in Europe. Similarly, LSV appear to be a still unclassified group of viruses with unclear impact on colony health and these viruses have not previously been identified outside of the United States. Furthermore, our study also reveals that these bees carried a plant virus, Turnip Ringspot Virus (TuRSV), potentially serving as important vector organisms. Taken together, these results demonstrate the new possibilities opened up by high-throughput sequencing and metagenomic analysis to study emerging new diseases in domestic and wild animal populations, including honeybees.

Rubio-Guerri, Consuelo; Karlsson, Oskar E.; Kukielka, Deborah; Belak, Sandor; Sanchez-Vizcaino, Jose Manuel

2013-01-01

126

Detection of Viral Pathogens by Reverse Transcriptase PCR and of Microbial Indicators by Standard Methods in the Canals of the Florida Keys  

PubMed Central

In order to assess the microbial water quality in canal waters throughout the Florida Keys, a survey was conducted to determine the concentration of microbial fecal indicators and the presence of human pathogenic microorganisms. A total of 19 sites, including 17 canal sites and 2 nearshore water sites, were assayed for total coliforms, fecal coliforms, Escherichia coli, Clostridium perfringens, enterococci, coliphages, F-specific (F+) RNA coliphages, Giardia lamblia, Cryptosporidium parvum, and human enteric viruses (polioviruses, coxsackie A and B viruses, echoviruses, hepatitis A viruses, Norwalk viruses, and small round-structured viruses). Numbers of coliforms ranged from <1 to 1,410, E. coli organisms from <1 to 130, Clostridium spp. from <1 to 520, and enterococci from <1 to 800 CFU/100 ml of sample. Two sites were positive for coliphages, but no F+ phages were identified. The sites were ranked according to microbial water quality and compared to various water quality standards and guidelines. Seventy-nine percent of the sites were positive for the presence of enteroviruses by reverse transcriptase PCR (polioviruses, coxsackie A and B viruses, and echoviruses). Sixty-three percent of the sites were positive for the presence of hepatitis A viruses. Ten percent of the sites were positive for the presence of Norwalk viruses. Ninety-five percent of the sites were positive for at least one of the virus groups. These results indicate that the canals and nearshore waters throughout the Florida Keys are being impacted by human fecal material carrying human enteric viruses through current wastewater treatment strategies such as septic tanks. Exposure to canal waters through recreation and work may be contributing to human health risks.

Griffin, Dale W.; Gibson, Charles J.; Lipp, Erin K.; Riley, Kelley; Paul, John H.; Rose, Joan B.

1999-01-01

127

Viral information.  

PubMed

Viruses are major drivers of global biogeochemistry and the etiological agents of many diseases. They are also the winners in the game of life: there are more viruses on the planet than cellular organisms and they encode most of the genetic diversity on the planet. In fact, it is reasonable to view life as a viral incubator. Nevertheless, most ecological and evolutionary theories were developed, and continue to be developed, without considering the virosphere. This means these theories need to be to reinterpreted in light of viral knowledge or we need to develop new theory from the viral point-of-view. Here we briefly introduce our viral planet and then address a major outstanding question in biology: why is most of life viral? A key insight is that during an infection cycle the original virus is completely broken down and only the associated information is passed on to the next generation. This is different for cellular organisms, which must pass on some physical part of themselves from generation to generation. Based on this premise, it is proposed that the thermodynamic consequences of physical information (e.g., Landauer's principle) are observed in natural viral populations. This link between physical and genetic information is then used to develop the Viral Information Hypothesis, which states that genetic information replicates itself to the detriment of system energy efficiency (i.e., is viral in nature). Finally, we show how viral information can be tested, and illustrate how this novel view can explain existing ecological and evolutionary theories from more fundamental principles. PMID:23482918

Rohwer, Forest; Barott, Katie

2012-10-31

128

Viral Infections  

MedlinePLUS

... also cause severe illnesses such as HIV/AIDS, smallpox and hemorrhagic fevers. Viruses are like hijackers. They ... work for viral infections. There are a few antiviral medicines available. Vaccines can help prevent you from ...

129

Experimental Bacterial and Viral Diarrhea (Experimental Viral Diarrhea in Pigs).  

National Technical Information Service (NTIS)

This investigation was undertaken to develop a system by which one could induce viral and/or bacterial diarrhea in pigs at will, and study the physiological and morphological changes induced by the pathogen preceeding overt signs of diarrhea. A strain of ...

L. R. Otero-Vilardebo

1981-01-01

130

[Viral hepatitis].  

PubMed

Viral hepatitis is associated with significant morbidity and mortality worldwide. Hepatitis A and E viruses are enterally transmitted and lead to usually self-limited acute hepatitis. Hepatitis B, C and D viruses are transmitted by parenteral routes and can lead to chronic hepatitis with progression to liver cirrhosis and hepatocellular carcinoma. Here, we briefly review current understanding and new developments in the virology and epidemiology, diagnosis, natural history, therapy and prevention of viral hepatitis. PMID:21452137

Moradpour, Darius; Blum, Hubert E

2011-04-01

131

Viral Hepatitis  

Microsoft Academic Search

Various forms of viral hepatitis have been identified as being sexually transmitted infections (STIs), whereas other forms\\u000a are transmitted primarily via oralfecal routes. The most common forms of viral hepatitis are hepatitis A, B, and C. Hepatitis\\u000a A virus (HAV) infection is most often a benign self-limiting disease; however, it can progress to fulminant liver failure.\\u000a Fecal-oral transmission though contact

Michelle L. Geller; Jeremy R. Herman

132

Common Threads in Persistent Viral Infections?  

PubMed Central

Most viral infections are self-limiting, resulting in either clearance of the pathogen or death of the host. However, a subset of viruses can establish permanent infection and persist indefinitely within the host. Even though persisting viruses are derived from various viral families with distinct replication strategies, they all utilize common mechanisms for establishment of long-lasting infections. Here, we discuss the commonalities between persistent infections with herpes-, retro-, flavi-, arena-, and polyomaviruses that distinguish them from acutely infecting viral pathogens. These shared strategies include selection of cell subsets ideal for long-term maintenance of the viral genome, modulation of viral gene expression, viral subversion of apoptotic pathways, and avoidance of clearance by the immune system.

Kane, Melissa; Golovkina, Tatyana

2010-01-01

133

Molecular biology of bovine viral diarrhea virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bovine viral diarrhea viruses (BVDV) are arguably the most important viral pathogen of ruminants worldwide and can cause severe economic loss. Clinical symptoms of the disease caused by BVDV range from subclinical to severe acute hemorrhagic syndrome, with the severity of disease being strain depend...

134

Autophagy and viral neurovirulence  

PubMed Central

Summary As terminally differentiated vital cells, neurons may be specialized to fight viral infections without undergoing cellular self-destruction. The cellular lysosomal degradation pathway, autophagy, is emerging as one such mechanism of neuronal antiviral defence. Autophagy has diverse physiological functions, such as cellular adaptation to stress, routine organelle and protein turnover, and innate immunity against intracellular pathogens, including viruses. Most of the in vivo evidence for an antiviral role of autophagy is related to viruses that specifically target neurons, including the prototype alphavirus, Sindbis virus, and the ?-herpesvirus, herpes simplex virus type 1 (HSV-1). In the case of HSV-1, viral evasion of autophagy is essential for lethal encephalitis. As basal autophagy is important in preventing neurodegeneration, and induced autophagy is important in promoting cellular survival during stress, viral antagonism of autophagy in neurons may lead to neuronal dysfunction and/or neuronal cell death. This review provides background information on the roles of autophagy in immunity and neuroprotection, and then discusses the relationships between autophagy and viral neurovirulence.

Orvedahl, Anthony; Levine, Beth

2009-01-01

135

Molecular basis of viral and microbial pathogenesis  

SciTech Connect

The contents of this book are: Correlation Between Viroid Structure and Pathogenicty; Antigenicity of the Influenza Haemagglutinia Membrane Glycoprotein; Viral Glycoproteins as Determinants of Pathogenicity; Virus Genes Involved in Host Range and Pathogenicity; Molecular Heterogenetiy of Pathogenic Herpus Viruses; Recombination of Foreign (Viral) DNA with Host Genome: Studies in Vivo and in a Cell-Free system; Disorders of Cellular Neuro-Functions by Persistent Viral Infection; Pathogenic Aspects of Measles Virus-Persistent Infections in Man; Analysis of the Dual Lineage Specificity of E26 Avian Leukemia Virus; Mx Gene Control of Influenza Virus Susceptibility; Shiga and Shika-Like Toxins: A Family of Related Cytokinons; and Molecular Mechanisms of Pathogenicity in Shigella Flexneri.

Rott, R.; Goebel, W.

1988-01-01

136

VIRAL GASTROENTERITIS  

EPA Science Inventory

Two virus types have been clearly shown to have epidemiologic importance in viral gastroenteritis, i.e., rotavirus and Norwalk virus. Four other virus types have been associated with gastroenteritis but their epidemiologic importance is not yet known, i.e., enteric adenovirus, ca...

137

Viral Subversion of the Nuclear Pore Complex  

PubMed Central

The nuclear pore complex (NPC) acts as a selective barrier between the nucleus and the cytoplasm and is responsible for mediating communication by regulating the transport of RNA and proteins. Numerous viral pathogens have evolved different mechanisms to hijack the NPC in order to regulate trafficking of viral proteins, genomes and even capsids into and out of the nucleus thus promoting virus replication. The present review examines the different strategies and the specific nucleoporins utilized during viral infections as a means of promoting their life cycle and inhibiting host viral defenses.

Le Sage, Valerie; Mouland, Andrew J.

2013-01-01

138

Viral subversion of the nuclear pore complex.  

PubMed

The nuclear pore complex (NPC) acts as a selective barrier between the nucleus and the cytoplasm and is responsible for mediating communication by regulating the transport of RNA and proteins. Numerous viral pathogens have evolved different mechanisms to hijack the NPC in order to regulate trafficking of viral proteins, genomes and even capsids into and out of the nucleus thus promoting virus replication. The present review examines the different strategies and the specific nucleoporins utilized during viral infections as a means of promoting their life cycle and inhibiting host viral defenses. PMID:23959328

Le Sage, Valerie; Mouland, Andrew J

2013-08-16

139

Viral evolution  

NASA Astrophysics Data System (ADS)

In the last two decades, viruses have been used as model systems to study evolution in short periods of time. Due to their characteristics, virus adapt rapidly to changing conditions, thus allowing the quantification of several evolutionary features under controlled laboratory conditions. Here we review the basic biology of viruses and describe in detail a number of experiments performed with RNA viruses. Particular emphasis is devoted to the interpretation of the experiments and to the involved phenomenology. This analysis sometimes represents the basis to formulate simple evolutionary models that aim at describing the observed dynamics. In other cases, theoretical results have prompted the realization of related experiments, as we discuss. Concepts as fitness loss and fitness recovery, the error threshold, increased mutagenesis, viral sex, or viral competition and interference, are discussed in an empirical framework and from the associated theoretical point of view.

Manrubia, Susanna C.; Lázaro, Ester

2006-06-01

140

DEVELOPMENT OF HUMAN BIOMARKERS OF EXPOSURE TO WATERBORNE PATHOGENS  

EPA Science Inventory

Contaminated drinking water is major source of waterborne diseases. EPA has published a drinking water contaminant candidate list (CCL) that contains a number of pathogens that potentially could be regulated in drinking water. Studies indicate that certain viral pathogens (adenov...

141

Effect of ultraviolet germicidal irradiation on viral aerosols.  

PubMed

Ultraviolet (UV) germicidal air disinfection is an engineering method used to control the airborne transmission of pathogenic microorganisms in high-risk settings. Despite the recent emergence of respiratory viral pathogens such as SARS and avian influenza viruses, UV disinfection of pathogenic viral aerosols has not been examined. Hence, we characterized the UV disinfection of viral aerosols using the bacteriophage MS2, adenovirus, and coronavirus. Our objectives were to characterize the effect of nebulization and air sampling on the survival of important viral pathogens, quantitatively characterize and estimate the UV susceptibility of pathogenic viral aerosols, and evaluate the effect of relative humidity (RH) on the susceptibility of viral aerosols, to 254 nm UV-C. The viruses were aerosolized into an experimental chamber using a six-jet Collison nebulizer, exposed to 254 nm UV, and sampled using an AGI-30 liquid impinger. Both the MS2 and adenovirus aerosols were very resistant to UV air disinfection, with a reduction of less than 1 logarithm in viable viral aerosols at a UV dose of 2608 microW s/cm2. The susceptibility of coronavirus aerosols was 7-10 times that of the MS2 and adenovirus aerosols. Unlike bacterial aerosols, there was no significant protective effect of high RH on UV susceptibility of the tested viral aerosols. We confirmed that the UV disinfection rate differs greatly between viral aerosols and viruses suspended in liquid. PMID:17822117

Walker, Christopher M; Ko, Gwangpyo

2007-08-01

142

Viral vectors for vaccine applications  

PubMed Central

Traditional approach of inactivated or live-attenuated vaccine immunization has resulted in impressive success in the reduction and control of infectious disease outbreaks. However, many pathogens remain less amenable to deal with the traditional vaccine strategies, and more appropriate vaccine strategy is in need. Recent discoveries that led to increased understanding of viral molecular biology and genetics has rendered the used of viruses as vaccine platforms and as potential anti-cancer agents. Due to their ability to effectively induce both humoral and cell-mediated immune responses, viral vectors are deemed as an attractive alternative to the traditional platforms to deliver vaccine antigens as well as to specifically target and kill tumor cells. With potential targets ranging from cancers to a vast number of infectious diseases, the benefits resulting from successful application of viral vectors to prevent and treat human diseases can be immense.

Choi, Youngjoo

2013-01-01

143

What makes pathogens pathogenic  

PubMed Central

Metazoans contain multiple complex microbial ecosystems in which the balance between host and microbe can be tipped from commensalism to pathogenicity. This transition is likely to depend both on the prevailing environmental conditions and on specific gene-gene interactions placed within the context of the entire ecosystem.

Ehrlich, Garth D; Hiller, N Luisa; Hu, Fen Ze

2008-01-01

144

DC-SIGN: escape mechanism for pathogens  

Microsoft Academic Search

Dendritic cells (DCs) are crucial in the defence against pathogens. Invading pathogens are recognized by Toll-like receptors (TLRs) and receptors such as C-type lectins expressed on the surface of DCs. However, it is becoming evident that some pathogens, including viruses, such as HIV-1, and non-viral pathogens, such as Mycobacterium tuberculosis, subvert DC functions to escape immune surveillance by targeting the

Teunis B. H. Geijtenbeek; Yvette van Kooyk

2003-01-01

145

Processes for managing pathogens.  

PubMed

Wastewater contains human, animal, and plant pathogens capable of causing viral, bacterial, or parasitic infections. There are several routes whereby sewage pathogens may affect human health, including direct contact, contamination of food crops, zoonoses, and vectors. The range and numbers of pathogens in municipal wastewater vary with the level of endemic disease in the community, discharges from commercial activities, and seasonal factors. Regulations to control pathogen risk in the United States and Europe arising from land application of biosolids are based on the concept of multiple barriers to the prevention of transmission. The barriers are (i) treatment to reduce pathogen content and vector attraction, (ii) restrictions on crops grown on land to which biosolids have been applied, and (iii) minimum intervals following application and grazing or harvesting. Wastewater treatment reduces number of pathogens in the wastewater by concentrating them with the solids in the sludge. Although some treatment processes are designed specifically to inactivate pathogens, many are not, and the actual mechanisms of microbial inactivation are not fully understood for all processes. Vector attraction is reduced by stabilization (reduction of readily biodegradable material) and/or incorporation immediately following application. Concerns about health risks have renewed interest in the effects of treatment (on pathogens) and advanced treatment methods, and work performed in the United States suggests that Class A pathogen reduction can be achieved less expensively than previously thought. Effective pathogen risk management requires control to the complete chain of sludge treatment, biosolids handling and application, and post-application activities. This may be achieved by adherence to quality management systems based on hazard analysis critical control point (HACCP) principles. PMID:15647539

Godfree, Alan; Farrell, Joseph

146

Viral quasispecies evolution.  

PubMed

Evolution of RNA viruses occurs through disequilibria of collections of closely related mutant spectra or mutant clouds termed viral quasispecies. Here we review the origin of the quasispecies concept and some biological implications of quasispecies dynamics. Two main aspects are addressed: (i) mutant clouds as reservoirs of phenotypic variants for virus adaptability and (ii) the internal interactions that are established within mutant spectra that render a virus ensemble the unit of selection. The understanding of viruses as quasispecies has led to new antiviral designs, such as lethal mutagenesis, whose aim is to drive viruses toward low fitness values with limited chances of fitness recovery. The impact of quasispecies for three salient human pathogens, human immunodeficiency virus and the hepatitis B and C viruses, is reviewed, with emphasis on antiviral treatment strategies. Finally, extensions of quasispecies to nonviral systems are briefly mentioned to emphasize the broad applicability of quasispecies theory. PMID:22688811

Domingo, Esteban; Sheldon, Julie; Perales, Celia

2012-06-01

147

Host–Pathogen Systems Biology  

Microsoft Academic Search

\\u000a Unlike traditional biological research that focuses on a small set of components, systems biology studies the complex interactions\\u000a among a large number of genes, proteins, and other elements of biological networks and systems. Host-pathogen systems biology\\u000a examines the interactions between the components of two distinct organisms: a microbial or viral pathogen and its animal host.\\u000a With the availability of complete

Christian V. Forst

148

MARINE MAMMAL DISEASES: PATHOGENS AND PROCESSES  

EPA Science Inventory

The purpose of this chapter is to provide a concise overview of the pathogens and processes that alter the health of marine mammals. Viral disease is the most common etiology of significant mortality events in marine mammals. Discussion of viral disease focuses on effects in the ...

149

Bioterrorism: pathogens as weapons.  

PubMed

Biowarfare has been used for centuries. The use of biological weapons in terrorism remains a threat. Biological weapons include infectious agents (pathogens) and toxins. The most devastating bioterrorism scenario would be the airborne dispersal of pathogens over a concentrated population area. Characteristics that make a specific pathogen a high-risk for bioterrorism include a low infective dose, ability to be aerosolized, high contagiousness, and survival in a variety of environmental conditions. The most dangerous potential bioterrorism agents include the microorganisms that produce anthrax, plague, tularemia, and smallpox. Other diseases of interest to bioterrorism include brucellosis, glanders, melioidosis, Q fever, and viral encephalitis. Food safety and water safety threats are another area of concern. PMID:23011963

Anderson, Peter D; Bokor, Gyula

2012-10-01

150

Detection of 11 Common Viral and Bacterial Pathogens Causing Community-Acquired Pneumonia or Sepsis in Asymptomatic Patients by Using a Multiplex Reverse Transcription-PCR Assay with Manual (Enzyme Hybridization) or Automated (Electronic Microarray) Detection  

Microsoft Academic Search

Community-acquired pneumonia (CAP) and sepsis are important causes of morbidity and mortality. We describe the development of two molecular assays for the detection of 11 common viral and bacterial agents of CAP and sepsis: influenza virus A, influenza virus B, respiratory syncytial virus A (RSV A), RSV B, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, Legionella micdadei, Bordetella pertussis, Staph- ylococcus

Swati Kumar; Lihua Wang; Jiang Fan; Andrea Kraft; Michael E. Bose; Sagarika Tiwari; Meredith Van Dyke; Robert Haigis; Tingquo Luo; Madhushree Ghosh; Huong Tang; Marjan Haghnia; Elizabeth L. Mather; William G. Weisburg; Kelly J. Henrickson

2008-01-01

151

Detection of 11 Common Viral and Bacterial Pathogens Causing Community-Acquired Pneumonia or Sepsis in Asymptomatic Patients by Using a Multiplex Reverse Transcription-PCR Assay with Manual (Enzyme Hybridization) or Automated (Electronic Microarray) Detection  

Microsoft Academic Search

Community-acquired pneumonia (CAP) and sepsis are important causes of morbidity and mortality. We describe the development of two molecular assays for the detection of 11 common viral and bacterial agents of CAP and sepsis: influenza virus A, influenza virus B, respiratory syncytial virus A (RSV A), RSV B, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, Legionella micdadei, Bordetella pertussis, Staph- ylococcus

Swati Kumar; Lihua Wang; Jiang Fan; Andrea Kraft; Michael E. Bose; Sagarika Tiwari; Meredith Van Dyke; Robert Haigis; Tingquo Luo; Madhushree Ghosh; Huong Tang; Marjan Haghnia; Elizabeth L. Mather; William G. Weisburg; Kelly J. Henrickson

152

Viral hepatitis*  

PubMed Central

Three forms of viral hepatitis can be recognized: hepatitis A, hepatitis B, and hepatitis non-A, non-B. Hepatitis A is caused by a picornavirus, is transmitted by the faceal—oral route, does not become chronic, and no chronic virus carriers exist. The virus can be grown in cell cultures, and killed as well as live attenuated virus vaccines are under development. Hepatitis B is caused by an enveloped virus containing a circular, double-stranded form of DNA. The disease is transmitted parenterally through inoculation of blood or blood products containing virus or through close personal contact with a virus-positive person. Hepatitis B becomes chronic in a certain number of cases and can lead to cirrhosis and primary liver cell carcinoma. The blood and certain body secretions of individuals with a persistent or chronic infection may remain infectious for many years. The hepatitis B virus cannot be grown in cell cultures but the entire genome has been sequenced and cloned in bacterial and eukaryotic cells. An inactivated virus vaccine has been prepared from hepatitis B surface antigen present in the plasma of hepatitis B virus carriers and further vaccines are under development. The agents of hepatitis non-A, non-B have not been identified. It is possible to distinguish between a predominantly parenterally transmitted and an orally transmitted form of hepatitis non-A, non-B. The latter is reported to be caused by a picornavirus that does not, however, have any antigenic relationship with hepatitis A virus.

Deinhardt, F.; Gust, I. D.

1982-01-01

153

Central roles of NLRs and inflammasomes in viral infection  

Microsoft Academic Search

The immune response to viral infections is determined by a complex interplay between the pathogen and the host. Innate immune cells express a set of cytosolic sensors to detect viral infection. Recognition by these sensors induces the production of type I interferons and the assembly of inflammasome complexes that activate caspase-1, leading to production of interleukin-1? (IL-1?) and IL-18. Here,

Thirumala-Devi Kanneganti

2010-01-01

154

20 VIRAL INFECTION  

Microsoft Academic Search

Approach to Viral Exposure Compared with primary care physicians, such as internists, fami- ly physicians, and pediatricians, surgeons are seldom called on to treat viral infections.Viral infections nonetheless deserve the atten- tion of surgeons because these infections can cause illness in patients after operation, albeit infrequently, and can spread to the hospital staff. Some viral infections (e.g., infections with the

Jennifer W. Janelle; Richard J. Howard

2002-01-01

155

Molecular biology of bovine viral diarrhea virus.  

PubMed

Bovine viral diarrhea viruses (BVDV) are arguably the most important viral pathogen of ruminants worldwide and can cause severe economic loss. Clinical symptoms of the disease caused by BVDV range from subclinical to severe acute hemorrhagic syndrome, with the severity of disease being strain dependent. These viruses are classified as members of the Pestivirus genus of the Flaviviridae. BVDV are considered primarily a pathogen of cattle but can infect most ruminant species. The virus particle consists of a lipid bilayer membrane surrounding the encapsidated genomic RNA. Inserted in the outer membrane are two virus-encoded glycoproteins that contain the major antigenic determinants of the virus as well as receptor binding and cell fusion functions. A third glycoprotein is weakly associated with the virion, but also possesses unique features that play important roles in suppression of innate immunity. The viral proteins are encoded in a single, large open reading frame. The viral proteins are proteolytically cleaved from the polyprotein by different proteases. The structural proteins are processed by cellular signal peptidases while the processing of the nonstructural proteins is by the viral serine protease. The virus is assembled and matures in the endoplasmic reticulum and golgi bodies of the cell. The virus is released via exocytosis, where viral proteins are not exposed on the surface of the cell. PMID:22884672

Neill, John D

2012-08-11

156

Severe Viral Infections and Primary Immunodeficiencies  

PubMed Central

Patients with severe viral infections are often not thoroughly evaluated for immunodeficiencies. In this review, we summarize primary immunodeficiencies that predispose individuals to severe viral infections. Some immunodeficiencies enhance susceptibility to disease with a specific virus or family of viruses, whereas others predispose to diseases with multiple viruses in addition to disease with other microbes. Although the role of cytotoxic T cells in controlling viral infections is well known, a number of immunodeficiencies that predispose to severe viral diseases have recently been ascribed to defects in the Toll-like receptor–interferon signaling pathway. These immunodeficiencies are rare, but it is important to identify them both for prognostic information and for genetic counseling. Undoubtedly, additional mutations in proteins in the innate and adaptive arms of the immune system will be identified in the future, which will reveal the importance of these proteins in controlling infections caused by viruses and other pathogens.

Cohen, Jeffrey I.

2011-01-01

157

Viral Infection after Renal Transplantation: Surveillance and Management  

PubMed Central

Viral infections remain a significant cause of morbidity and mortality following renal transplantation. Although cytomegalovirus is the most common opportunistic pathogen seen in transplant recipients, numerous other viruses have also affected outcomes. In some cases, preventive measures such as pretransplant screening, prophylactic antiviral therapy, or post transplant viral monitoring may limit the impact of these infections. Recent advances in laboratory monitoring and antiviral therapy have improved outcomes. This review will summarize the major viral infections seen following transplant and discuss strategies for prevention and management of these potential pathogens.

Weikert, Blair C.; Blumberg, Emily A.

2008-01-01

158

Native microbiota shape insect vector competence for human pathogens  

PubMed Central

Summary The resident microbiota of insect vectors can impede transmission of human pathogens. Recent studies have highlighted the capacity of endogenous bacteria to decrease viral and parasitic infections in mosquito and tsetse fly vectors by activating their immune responses or directly inhibiting pathogen development. These microbes may prove effective agents for manipulating the vector competence of malaria and other important human pathogens.

Cirimotich, Chris M.; Ramirez, Jose L.; Dimopoulos, George

2012-01-01

159

COPI Activity Coupled with Fatty Acid Biosynthesis Is Required for Viral Replication  

Microsoft Academic Search

During infection by diverse viral families, RNA replication occurs on the surface of virally induced cytoplasmic membranes of cellular origin. How this process is regulated, and which cellular factors are required, has been unclear. Moreover, the host-pathogen interactions that facilitate the formation of this new compartment might represent critical determinants of viral pathogenesis, and their elucidation may lead to novel

Sara Cherry; Amit Kunte; Hui Wang; Carolyn Coyne; Robert B. Rawson; Norbert Perrimon

2006-01-01

160

The PA and HA Gene-Mediated High Viral Load and Intense Innate Immune Response in the Brain Contribute to the High Pathogenicity of H5N1 Avian Influenza Virus in Mallard Ducks.  

PubMed

Most highly pathogenic avian influenza A viruses cause only mild clinical signs in ducks, serving as an important natural reservoir of influenza A viruses. However, we isolated two H5N1 viruses that are genetically similar but differ greatly in virulence in ducks. A/Chicken/Jiangsu/k0402/2010 (CK10) is highly pathogenic, whereas A/Goose/Jiangsu/k0403/2010 (GS10) is low pathogenic. To determine the genetic basis for the high virulence of CK10 in ducks, we generated a series of single-gene reassortants between CK10 and GS10 and tested their virulence in ducks. Expression of the CK10 PA or hemagglutinin (HA) gene in the GS10 context resulted in increased virulence and virus replication. Conversely, inclusion of the GS10 PA or HA gene in the CK10 background attenuated the virulence and virus replication. Moreover, the PA gene had a greater contribution. We further determined that residues 101G and 237E in the PA gene contribute to the high virulence of CK10. Mutations at these two positions produced changes in virulence, virus replication, and polymerase activity of CK10 or GS10. Position 237 plays a greater role in determining these phenotypes. Moreover, the K237E mutation in the GS10 PA gene increased PA nuclear accumulation. Mutant GS10 viruses carrying the CK10 HA gene or the PA101G or PA237E mutation induced an enhanced innate immune response. A sustained innate response was detected in the brain rather than in the lung and spleen. Our results suggest that the PA and HA gene-mediated high virus replication and the intense innate immune response in the brain contribute to the high virulence of H5N1 virus in ducks. PMID:23926340

Hu, Jiao; Hu, Zenglei; Mo, Yiqun; Wu, Qiwen; Cui, Zhu; Duan, Zhiqiang; Huang, Junqing; Chen, Hongzhi; Chen, Yuxin; Gu, Min; Wang, Xiaoquan; Hu, Shunlin; Liu, Huimou; Liu, Wenbo; Liu, Xiaowen; Liu, Xiufan

2013-08-07

161

Sensitive Detection of Viral Transcripts in Human Tumor Transcriptomes  

PubMed Central

In excess of % of human cancer incidents have a viral cofactor. Epidemiological studies of idiopathic human cancers indicate that additional tumor viruses remain to be discovered. Recent advances in sequencing technology have enabled systematic screenings of human tumor transcriptomes for viral transcripts. However, technical problems such as low abundances of viral transcripts in large volumes of sequencing data, viral sequence divergence, and homology between viral and human factors significantly confound identification of tumor viruses. We have developed a novel computational approach for detecting viral transcripts in human cancers that takes the aforementioned confounding factors into account and is applicable to a wide variety of viruses and tumors. We apply the approach to conducting the first systematic search for viruses in neuroblastoma, the most common cancer in infancy. The diverse clinical progression of this disease as well as related epidemiological and virological findings are highly suggestive of a pathogenic cofactor. However, a viral etiology of neuroblastoma is currently contested. We mapped transcriptomes of neuroblastoma as well as positive and negative controls to the human and all known viral genomes in order to detect both known and unknown viruses. Analysis of controls, comparisons with related methods, and statistical estimates demonstrate the high sensitivity of our approach. Detailed investigation of putative viral transcripts within neuroblastoma samples did not provide evidence for the existence of any known human viruses. Likewise, de-novo assembly and analysis of chimeric transcripts did not result in expression signatures associated with novel human pathogens. While confounding factors such as sample dilution or viral clearance in progressed tumors may mask viral cofactors in the data, in principle, this is rendered less likely by the high sensitivity of our approach and the number of biological replicates analyzed. Therefore, our results suggest that frequent viral cofactors of metastatic neuroblastoma are unlikely.

Schelhorn, Sven-Eric; Fischer, Matthias; Tolosi, Laura; Altmuller, Janine; Nurnberg, Peter; Pfister, Herbert; Lengauer, Thomas; Berthold, Frank

2013-01-01

162

Adequacy of Disinfection for Control of Newly Recognized Waterborne Pathogens.  

National Technical Information Service (NTIS)

Agents recently recognized as causes or potential causes of waterborne outbreaks include pathogenic bacteria (Campylobacter jejuni, Yersinia enterocoliticia), viruses (rotavirus, Norwalk virus and other poorly defined viral agents) and Giardia lamblia, a ...

J. C. Hoff E. E. Gerldreich

1982-01-01

163

Management of viral infections in solid organ transplant recipients.  

PubMed

Management of viral infections after transplantation involves antiviral drug therapy (if available) and reduction in immunosuppression, which allows for development of pathogen-specific immunity to the offending virus. Prevention of viral infections is of the utmost importance, and this may be accomplished through vaccination, antiviral strategies and infection control measures. This article discusses the current management of selected viral pathogens that cause clinical illness in solid organ transplant recipients. The benefits and toxicities of antiviral therapies are discussed in the context of prevention and treatment of various viral diseases. The emerging issue of antiviral resistance is emphasized for cytomegalovirus, recurrent hepatitis B and influenza, while the importance of immunominimization is discussed in the management of BK nephropathy and virus-associated malignancies. PMID:21692673

Razonable, Raymund R

2011-06-01

164

Ice as a reservoir for pathogenic human viruses: specifically, caliciviruses, influenza viruses, and enteroviruses  

Microsoft Academic Search

Hundreds of isolates of viable bacteria and fungi have been recovered from ancient ice and permafrost. Evidence supports the hypothesis that viral pathogens also are preserved in ice repositories, such as glaciers, ice sheets, and lake ice. Proof may depend upon narrowing the search by applying specific criteria, which would target candidate viruses. Such criteria include viral pathogens likely to

Alvin W. Smith; Douglas E. Skilling; John D. Castello; Scott O. Rogers

2004-01-01

165

Structural and dynamic studies of viral capsid proteins  

Microsoft Academic Search

West Nile virus(WN) is a member of the flavivirus Flaviviridae family and is one of the most significant human viral pathogens. The virus is comprised of a nucleocapsid core that consists of a viral RNA genome encapsidated by capsid protein, which is surrounded by a host-derived lipid bilayer and membrane-embedded envelope glycoproteins. The capsid protein (CP) plays key roles during

Jae Eun Suk

2008-01-01

166

Viral epidemiology of acute exacerbations of chronic obstructive pulmonary disease.  

PubMed

The role of viruses in Acute Exacerbations of Chronic Obstructive Pulmonary Disease (AECOPD) needs further elucidation. The aim of the present study was to evaluate the molecular epidemiology of viral pathogens in AECOPD. Patients presenting to the Emergency Room with AECOPD needing hospitalization were recruited. Oropharyngeal and sputum samples were collected in order to perform microarrays-based viral testing for the detection of respiratory viruses. A total of 200 (100%) patients were analyzed and from them in 107 (53.5%) a virus was detected. The commonest identified viruses were the human Respiratory Syncytial Virus (subtypes A and B) (40.5%), influenza virus (subtypes A, B, C) (11%), rhinovirus (8%) and human Parainfluenza Virus (subtypes A and B) (7.5%). A bacterial pathogen was isolated in 27 (14%) patients and a dual infection due to a bacterial and a viral pathogen was recognised in 14/107 patients. Patients with AECOPD and a viral infection had a lengthier hospital stay (9.2 ± 4.6 vs 7.6 ± 4.3, p < 0.01) while the severity of the disease was no related with significant differences among the groups of the study population. In conclusion, the isolation of a virus was strongly associated with AECOPD in the examined population. The stage of COPD appeared to have no relation with the frequency of the isolated viruses while dual infection with a viral and a bacterial pathogen was not rare. PMID:21983132

Dimopoulos, G; Lerikou, M; Tsiodras, S; Chranioti, Aik; Perros, E; Anagnostopoulou, U; Armaganidis, A; Karakitsos, P

2011-09-29

167

Emerging viral diseases in kidney transplant recipients.  

PubMed

Viruses are the most important cause of infections and a major source of mortality in Kidney Transplant Recipients (KTRs). These patients may acquire viral infections through exogenous routes including community exposure, donor organs, and blood products or by endogenous reactivation of latent viruses. Beside major opportunistic infections due to CMV and EBV and viral hepatitis B and C, several viral diseases have recently emerged in KTRs. New medical practices or technologies, implementation of new diagnostic tools, and improved medical information have contributed to the emergence of these viral diseases in this special population. The purpose of this review is to summarize the current knowledge on emerging viral diseases and newly discovered viruses in KTRs over the last two decades. We identified viruses in the field of KT that had shown the greatest increase in numbers of citations in the NCBI PubMed database. BKV was the most cited in the literature and linked to an emerging disease that represents a great clinical concern in KTRs. HHV-8, PVB19, WNV, JCV, H1N1 influenza virus A, HEV, and GB virus were the main other emerging viruses. Excluding HHV8, newly discovered viruses have been infrequently linked to clinical diseases in KTRs. Nonetheless, pathogenicity can emerge long after the discovery of the causative agent, as has been the case for BKV. Overall, antiviral treatments are very limited, and reducing immunosuppressive therapy remains the cornerstone of management. PMID:23132728

Moal, Valérie; Zandotti, Christine; Colson, Philippe

2012-11-07

168

[Viral hepatitis during pregnancy].  

PubMed

Viral hepatitis is one of the most common liver diseases appearing during pregnancy. Prevention against hepatotropic viruses is restricted due to lack of vaccines being effective in induction of efficient immunization in the majority of these microorganisms. In general, there is no possibility of active immunization against hepatotropic viruses except type A and B viral hepatitis. An issue of viral hepatitis in pregnancy as an aspect of potential risk factor connected with infection of pregnant women and a fetus has been described in this paper. Furthermore, the most important topics in the field of the epidemiology, prophylaxis and possible treatment options of viral hepatitis A, B, C, D, E and G have been discussed. The newest reports of pregnant women lamivudine therapy as a preventive treatment against vertical transmission during delivery have been reviewed. Rarly diagnosed viral hepatitis caused by herpes simplex virus, cytomegalovirus, Epstein-Barr virus and adenoviruses have been characterized as well. PMID:17219815

Gutkowski, Krzysztof; Gutkowska, Dorota; Lepiech, Jacek

2006-10-01

169

Raw Sewage Harbors Diverse Viral Populations  

PubMed Central

ABSTRACT At this time, about 3,000 different viruses are recognized, but metagenomic studies suggest that these viruses are a small fraction of the viruses that exist in nature. We have explored viral diversity by deep sequencing nucleic acids obtained from virion populations enriched from raw sewage. We identified 234 known viruses, including 17 that infect humans. Plant, insect, and algal viruses as well as bacteriophages were also present. These viruses represented 26 taxonomic families and included viruses with single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), positive-sense ssRNA [ssRNA(+)], and dsRNA genomes. Novel viruses that could be placed in specific taxa represented 51 different families, making untreated wastewater the most diverse viral metagenome (genetic material recovered directly from environmental samples) examined thus far. However, the vast majority of sequence reads bore little or no sequence relation to known viruses and thus could not be placed into specific taxa. These results show that the vast majority of the viruses on Earth have not yet been characterized. Untreated wastewater provides a rich matrix for identifying novel viruses and for studying virus diversity. Importance At this time, virology is focused on the study of a relatively small number of viral species. Specific viruses are studied either because they are easily propagated in the laboratory or because they are associated with disease. The lack of knowledge of the size and characteristics of the viral universe and the diversity of viral genomes is a roadblock to understanding important issues, such as the origin of emerging pathogens and the extent of gene exchange among viruses. Untreated wastewater is an ideal system for assessing viral diversity because virion populations from large numbers of individuals are deposited and because raw sewage itself provides a rich environment for the growth of diverse host species and thus their viruses. These studies suggest that the viral universe is far more vast and diverse than previously suspected.

Cantalupo, Paul G.; Calgua, Byron; Zhao, Guoyan; Hundesa, Ayalkibet; Wier, Adam D.; Katz, Josh P.; Grabe, Michael; Hendrix, Roger W.; Girones, Rosina; Wang, David; Pipas, James M.

2011-01-01

170

RNAi suppressors encoded by pathogenic human viruses  

Microsoft Academic Search

RNA silencing or RNAi interference (RNAi) serves as an innate antiviral mechanism in plants, fungi and animals. Human viruses, like plant viruses, encode suppressor proteins or RNAs that block or modulate the RNAi pathway. This review summarizes the mechanisms by which pathogenic human viruses affect the RNAi pathway. Furthermore, some applications of the viral RNAi suppressor functions and the consequences

Walter de Vries; Ben Berkhout

2008-01-01

171

Challenging and emerging pathogens in cystic fibrosis.  

PubMed

Cystic fibrosis (CF) lung disease is characterised by chronic inflammation and infection. Patients are predominantly infected by specific pathogens, of which Staphylococcus aureus and Pseudomonas aeruginosa are the most important. In recent years however there has been an increasing number of reports on potentially emerging and challenging pathogens like Stenotrophomonas maltophilia, Non-tuberculous mycobacteria, highly prevalent P. aeruginosa clones, methicillin resistant Staphylococcus aureus and Burkholderia cepacia. Also, a role for viral infections in the pathogenesis of CF lung disease has increasingly been recognised. It is not always clear whether or how these pathogens influence the progression of CF lung disease and how they should be treated. In this review, the epidemiology and clinical impact of these pathogens is discussed. Furthermore, treatment strategies of these pathogens in a CF setting are reviewed. PMID:21109184

de Vrankrijker, A M M; Wolfs, T F W; van der Ent, C K

2010-08-07

172

Viral Hepatitis Therapies  

MedlinePLUS

... Cancer Liaison Program Cardiovascular Information Diabetes Information - Viral Hepatitis Therapies Click on drug brand name for additional information. Approved Treatments for Hepatitis B Brand Name Generic Names Manufacturer Name Indication ...

173

Classical Live Viral Vaccines  

Microsoft Academic Search

\\u000a Classical, live viral vaccines have been developed by adapting viruses by serial passages in animals, tissue or cell cultures\\u000a during which multiple mutations in the viral genome have accumulated. The majority of vaccines in use today were developed\\u000a in this way and a number of similar investigational vaccines are currently in development. The principal advantage of live\\u000a vaccines is that

Thomas P. Monath

174

Community Respiratory Viral Infections  

Microsoft Academic Search

\\u000a Transplantation has become an increasingly effective strategy for the treatment of many end-stage and life-threatening illnesses.\\u000a Despite many advances in post-transplant care, infection remains a major problem for transplant recipients. Although the specific\\u000a infectious complications vary among different transplant populations, viral infections are increasingly recognized to occur\\u000a in all types of transplant patients. Post-transplant viral infections can occur through reactivation

Lisa R. Young; Scott M. Palmer

175

Viral Discovery and Sequence Recovery Using DNA Microarrays  

Microsoft Academic Search

Because of the constant threat posed by emerging infectious diseases and the limitations of existing approaches used to identify new pathogens, there is a great demand for new technological methods for viral discovery. We describe herein a DNA microarray-based platform for novel virus identification and characterization. Central to this approach was a DNA microarray designed to detect a wide range

David Wang; Anatoly Urisman; Yu-Tsueng Liu; Michael Springer; Thomas G Ksiazek; Dean D Erdman; Elaine R Mardis; Matthew Hickenbotham; Vincent Magrini; James Eldred; J. Phillipe Latreille; Richard K Wilson; Don Ganem; Joseph L DeRisi

2003-01-01

176

Intranasal Antibody Prophylaxis for Protection against Viral Disease  

PubMed Central

For more than a century, antibody has been used for passive parenteral immunization against viral and bacterial pathogens. This approach has been successful for prevention of viral respiratory infection and has led to testing of intranasal or aerosol delivery of antibody to passively immunize the respiratory tract mucosal surface. Mucosal delivery may be advantageous because it allows the antibody to neutralize the virus particles before they initiate infection and because it concentrates the antibody where viral replication takes place. Animal studies have shown the feasibility of passive intranasal immunization against a number of respiratory tract viruses. Development of nasal antibody treatments for humans is under way, and early clinical studies have confirmed that this approach is safe and can be used to prevent respiratory tract disease. Polyclonal human immunoglobulin from pooled plasma preparations can be used to provide broad protection against a number of different pathogens, while monoclonal antibodies or their fragments can be used to target specific viruses.

Weltzin, Richard; Monath, Thomas P.

1999-01-01

177

Concepts in viral pathogenesis II  

SciTech Connect

This paper contains papers divided among 10 sections. The section titles are: Viral Structure and Function; Viral Constructs; Oncogenes, Transfection, and Differentiation; Viral Tropism and Entry into Cells; Immune Recognition of Viruses; Evolving Concepts in Viral Pathogenesis Illustrated by Selected Plant and Animal Models; Evolving Concepts in Viral Pathogenesis Illustrated by Selected Diseases in Humans; New Trends in Diagnosis and Epidemiology; and Vaccines and Antiviral Therapy.

Notkins, A.L.; Oldstone, M.B.A.

1986-01-01

178

Avian Diagnostic and Therapeutic Antibodies to Viral Emerging Pathogens  

SciTech Connect

During the current period the following key objectives were achieved: demonstration of high titer antibody production by geese following immunization with inactived H1N1 virus; completion of the epitope mapping of West Nile Virus-specific goose antibodies and initiation of epitope mapping of H1N1 flu-specific goose antibodies; advancement in scalable purification of goose antibodies.

David Bradley

2011-03-31

179

Coxsackie viral myocarditis  

PubMed Central

Coxsackie viral myocarditis is a common disease, yet idiopathic dilated cardiomyopathy is a less common consequence. Insights gained from studying the Coxsackie virus B-3 murine model of myocarditis has led to the hypothesis that an acute Coxsackie viral myocarditis can result in persistent, non-viral mediated cellular responses that result in a chronic inflammatory state leading to progressive myocyte loss and ultimate development of dilated cardiomyopathy. Although the evidence linking myocarditis to dilated cardiomyopathy is circumstantial in man, the identification of defects in immunoregulation may provide the impetus to further research into the pathogenesis and ultimately the development of more rational therapies directed at modulating immune responses to alter the natural history of clinical dilated cardiomyopathy.

O'Connell, John B.; Robinson, John A.

1985-01-01

180

Acute viral myocarditis  

PubMed Central

Acute myocarditis is one of the most challenging diagnosis in cardiology. At present, no diagnostic gold standard is generally accepted, due to the insensitivity of traditional diagnostic tests. This leads to the need for new diagnostic approaches, which resulted in the emergence of new molecular tests and a more detailed immunohistochemical analysis of endomyocardial biopsies. Recent findings using these new diagnostic tests resulted in increased interest in inflammatory cardiomyopathies and a better understanding of its pathophysiology, the recognition in overlap of virus-mediated damage, inflammation, and autoimmune dysregulation. Novel results also pointed towards a broader spectrum of viral genomes responsible for acute myocarditis, indicating a shift of enterovirus and adenovirus to parvovirus B19 and human herpes virus 6. The present review proposes a general diagnostic approach, focuses on the viral aetiology and associated autoimmune processes, and reviews treatment options for patients with acute viral myocarditis.

Dennert, Robert; Crijns, Harry J.; Heymans, Stephane

2008-01-01

181

Rapid Detection of Pathogens  

SciTech Connect

Pathogen identification is a crucial first defense against bioterrorism. A major emphasis of our national biodefense strategy is to establish fast, accurate and sensitive assays for diagnosis of infectious diseases agents. Such assays will ensure early and appropriate treatment of infected patients. Rapid diagnostics can also support infection control measures, which monitor and limit the spread of infectious diseases agents. Many select agents are highly transmissible in the early stages of disease, and it is critical to identify infected patients and limit the risk to the remainder of the population and to stem potential panic in the general population. Nucleic acid-based molecular approaches for identification overcome many of the deficiencies associated with conventional culture methods by exploiting both large- and small-scale genomic differences between organisms. PCR-based amplification of highly conserved ribosomal RNA (rRNA) genes, intergenic sequences, and specific toxin genes is currently the most reliable approach for bacterial, fungal and many viral pathogenic agents. When combined with fluorescence-based oligonucleotide detection systems, this approach provides real-time, quantitative, high fidelity analysis capable of single nucleotide allelic discrimination (4). These probe systems offer rapid turn around time (<2 h) and are suitable for high throughput, automated multiplex operations that are critical for clinical diagnostic laboratories. In this pilot program, we have used molecular beacon technology invented at the Public health Research Institute to develop a new generation of molecular probes to rapidly detect important agents of infectious diseases. We have also developed protocols to rapidly extract nucleic acids from a variety of clinical specimen including and blood and tissue to for detection in the molecular assays. This work represented a cooperative research development program between the Kramer-Tyagi/Perlin labs on probe development and the Perlin lab in sample preparation and testing in animal models.

David Perlin

2005-08-14

182

Advances in viral oncology  

SciTech Connect

Volume 6 of Advances in Viral Oncology presents experimental approaches to multifactorial interactions in tumor development. Included are in-depth analyses of malignant phenotypes by oncogene complementation, as well as studies of complementary interactions among DNA viral oncogenes; multiple cell-derived sequences in single retroviral genomes; and sequences that influence the transforming activity and expression of the mos oncogene. The genetic regulation of tumorigenic expression in somatic cell hybrids, the inhibition of oncogenes by cellular genes, and the interaction of genes that favor and genes that suppress tumorigenesis are examined in detail. The book concludes with a study of the relationship of oncogenes to the evolution of the metastatic phenotype.

Klein, G.

1987-01-01

183

Emerging viral infections.  

PubMed

Unique disorders appear episodically in human populations and cause life-threatening systemic or neurological disease. Historical examples of such disorders include von Economo encephalitis, a disorder of presumed viral etiology; acquired immune deficiency syndrome, caused by the human immunodeficiency virus; and severe acute respiratory syndrome, caused by a member of the coronavirus family. This article describes the factors that contribute to the emergence of infectious diseases and focuses on selected recent examples of emerging viral infections that can affect the nervous system of infants, children, and adolescents. PMID:22889544

Bale, James F

2012-09-01

184

The effects of bovine viral diarrhoea virus on cattle reproduction in relation to disease control  

Microsoft Academic Search

Bovine viral diarrhoea virus (BVDV) is a major reproductive pathogen in cattle. Infection of the bull can lead to a fall in semen quality and the isolation of infectious virus in the ejaculate, while infection in the cow leads to poor conception rates, abortions and congenital defects. BVDV also reduces the animal's resistance to other respiratory and enteric pathogens. The

M. D Fray; D. J Paton; S Alenius

2000-01-01

185

PARAINFLUENZA VIRUS-3 PULMONARY LESIONS ARE NOT ENHANCED BY BOVINE VIRAL DIARRHEA VIRUS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Parainfluenza virus-3 (PI-3) is a common respiratory pathogen of cattle and sheep. Bovine viral diarrhea virus (BVDV) is a common bovine pathogen that may enhance respiratory disease. Two groups of neonatal lambs were inoculated intranasally and intratracheally with PI-3/BVDV or PI-3 alone. Both...

186

Viral infections and asthma inception.  

PubMed

Respiratory tract infections caused by viruses have been implicated in the pathogenesis of asthma. Of these respiratory pathogens, viruses have been demonstrated to be associated with asthma epidemiologically in at least 3 ways ( Fig 1 ). First, during infancy, certain viruses have been implicated in the inception of the asthmatic phenotype. Genetic susceptibility, particularly genes coding for atopic phenotypic characteristics, might differentiate, at least in part, those children who are destined to have persistent wheezing, asthma, or both later in childhood. Second, repeated exposure to infectious viruses in daycare centers or in households with multiple older siblings increases the number of respiratory infections, but in doing so, it might paradoxically reduce the long-term risk of allergies and asthma through either pre-existing or newly formed alterations in cytokine response profiles. Third, in patients with established asthma, particularly children, viral upper respiratory tract infections play a significant role in producing acute exacerbations of airway obstruction that might result in frequent outpatient visits or in hospitalizations. This review will highlight available data on respiratory syncytial virus infections and their relationship to asthma inception in childhood. PMID:15536404

Lemanske, Robert F

2004-11-01

187

WATERBORNE VIRAL GASTROENTERITIS  

EPA Science Inventory

In the study of human gastroenteritis, the use of electron microscopy and related techniques has led to the identification of new viral agents which had previously escaped detection by routine cell-culture procedures. Efforts to characterize and further study these agents are cur...

188

Haraway's Viral Cyborg  

Microsoft Academic Search

Nearly thirty years ago, Donna Haraway began writing her famous essay published in 1985 as “A Manifesto for Cyborgs: Science, Technology, and Feminism in the 1980s.” In its vision, argument, and detail, it resonates strongly with what today is called viral analysis and criticism. In what follows I’ll briefly suggest how. First, the essay was blasphemous, transgressive, and invasive, arguably

Joseph Schneider

2012-01-01

189

VIRAL INFECTION OF RABBITS  

Microsoft Academic Search

The three most important viruses of rabbits include : Myxoma virus (MV), the poxvirus that causes Myxomatosis, the calicivirus ( genus Lagovirus) of Rabbit Haemorrhagic Disease (RHDV), and Lapine Rotavirus (LRV), which is an enteric agent. There a re some other viral agents in rabbits (parvovirus, coronavirus, adenovirus, calicivirus ( genus Vesivirus), enterovirus-like, reovirus, herpesvirus and coronavirus) but both their

190

Transport of viral specimens.  

PubMed Central

The diagnosis of viral infections by culture relies on the collection of proper specimens, proper care to protect the virus in the specimens from environmental damage, and use of an adequate transport system to maintain virus activity. Collection of specimens with swabs that are toxic to either virus or cell culture should be avoided. A variety of transport media have been formulated, beginning with early bacteriological transport media. Certain swab-tube combinations have proven to be both effective and convenient. Of the liquid transport media, sucrose-based and broth-based media appear to be the most widely accepted and used. Studies on virus stability show that most viruses tested are sufficiently stable in transport media to withstand a transport time of 1 to 3 days. Some viruses may withstand longer transport times. In many cases, it is not necessary to store virus specimens in a refrigerator or send them to the laboratory on wet ice or frozen on dry ice. However, the specimen should not be exposed to environmental extremes. Modern viral transport media allow for more effective use of viral culture and culture enhancement techniques for the diagnosis of human viral infections.

Johnson, F B

1990-01-01

191

Waterborne human pathogenic viruses of public health concern.  

PubMed

In recent years, the impending impact of waterborne pathogens on human health has become a growing concern. Drinking water and recreational exposure to polluted water have shown to be linked to viral infections, since viruses are shed in extremely high numbers in the faeces and vomit of infected individuals and are routinely introduced into the water environment. All of the identified pathogenic viruses that pose a significant public health threat in the water environment are transmitted via the faecal-oral route. This group, are collectively known as enteric viruses, and their possible health effects include gastroenteritis, paralysis, meningitis, hepatitis, respiratory illness and diarrhoea. This review addresses both past and recent investigations into viral contamination of surface waters, with emphasis on six types of potential waterborne human pathogenic viruses. In addition, the viral associated illnesses are outlined with reference to their pathogenesis and routes of transmission. PMID:23432800

Ganesh, Atheesha; Lin, Johnson

2013-02-22

192

Rare and emerging viral infections in transplant recipients.  

PubMed

Emerging viral pathogens include newly discovered viruses as well as previously known viruses that are either increasing, or threatening to increase in incidence. While often first identified in the general population, they may affect transplant recipients, in whom their manifestations may be atypical or more severe. Enhanced molecular methods have increased the rate of viral discovery but have not overcome the problem of demonstrating pathogenicity. At the same time, improved clinical diagnostic methods have increased the detection of reemerging viruses in immunocompromised patients. In this review, we first discuss viral diagnostics and the developing field of viral discovery and then focus on rare and emerging viruses in the transplant population: human T-cell leukemia virus type 1; hepatitis E virus; bocavirus; KI and WU polyomaviruses; coronaviruses HKU1 and NL63; influenza, H1N1; measles; dengue; rabies; and lymphocytic choriomeningitis virus. Detection and reporting of such rare pathogens in transplant recipients is critical to patient care and improving our understanding of posttransplant infections. PMID:23839998

Waggoner, Jesse J; Soda, Elizabeth A; Deresinski, Stan

2013-07-09

193

Inducible viral receptor, A possible concept to induce viral protection in primitive immune animals  

PubMed Central

A pseudolysogen (PL) is derived from the lysogenic Vibrio harveyi (VH) which is infected with the VHS1 (Vibrio harveyi Siphoviridae-like 1) bacteriophage. The lysogenic Vibrio harveyi undergoes an unequivalent division of the extra-chromosomal VHS1 phage genome and its VH host chromosome and produces a true lysogen (TL) and pseudolysogen (PL). The PL is tolerant to super-infection of VHS1, as is of the true lysogen (TL), but the PL does not contain the VHS1 phage genome while the TL does. However, the PL can become susceptible to VHS1 phage infection if the physiological state of the PL is changed. It is postulated that this is due to a phage receptor molecule which can be inducible to an on-and-off regulation influence by an alternating condition of the bacterial host cell. This characteristic of the PL leads to speculate that this phenomenon can also occur in high organisms with low immunity such as shrimp. This article proposes a hypothesis that the viral receptor molecule on the target cell can play a crucial role in which the invertebrate aquaculture animals can become tolerant to viral infection. A possible mechanism may be that the target cell disrupts the viral receptor molecule to prevent super infection. This concept can explain a mechanism for the prevention of viral infection in invertebrate animals which do not have acquired immunity in response to pathogens. It can guide us to develop a mechanism of immunity to viral infection in low-evolved-immune animals. Also, it can be an additional mechanism that exists in high immune organism, as in human for the prevention of viral infection

2011-01-01

194

Molecular Determinants of Enterovirus 71 Viral Entry  

PubMed Central

Enterovirus 71 (EV71) is one of the major pathogens that cause hand, foot, and mouth disease outbreaks in young children in the Asia-Pacific region in recent years. Human scavenger receptor class B 2 (SCARB2) is the main cellular receptor for EV71 on target cells. The requirements of the EV71-SCARB2 interaction have not been fully characterized, and it has not been determined whether SCARB2 serves as an uncoating receptor for EV71. Here we compared the efficiency of the receptor from different species including human, horseshoe bat, mouse, and hamster and demonstrated that the residues between 144 and 151 are critical for SCARB2 binding to viral capsid protein VP1 of EV71 and seven residues from the human receptor could convert murine SCARB2, an otherwise inefficient receptor, to an efficient receptor for EV71 viral infection. We also identified that EV71 binds to SCARB2 via a canyon of VP1 around residue Gln-172. Soluble SCARB2 could convert the EV71 virions from 160 S to 135 S particles, indicating that SCARB2 is an uncoating receptor of the virus. The uncoating efficiency of SCARB2 significantly increased in an acidic environment (pH 5.6). These studies elucidated the viral capsid and receptor determinants of enterovirus 71 infection and revealed a possible target for antiviral interventions.

Chen, Pan; Song, Zilin; Qi, Yonghe; Feng, Xiaofeng; Xu, Naiqing; Sun, Yinyan; Wu, Xing; Yao, Xin; Mao, Qunyin; Li, Xiuling; Dong, Wenjuan; Wan, Xiaobo; Huang, Niu; Shen, Xinliang; Liang, Zhenglun; Li, Wenhui

2012-01-01

195

Phylodynamic analysis of a viral infection network.  

PubMed

Viral infections by sexual and droplet transmission routes typically spread through a complex host-to-host contact network. Clarifying the transmission network and epidemiological parameters affecting the variations and dynamics of a specific pathogen is a major issue in the control of infectious diseases. However, conventional methods such as interview and/or classical phylogenetic analysis of viral gene sequences have inherent limitations and often fail to detect infectious clusters and transmission connections. Recent improvements in computational environments now permit the analysis of large datasets. In addition, novel analytical methods have been developed that serve to infer the evolutionary dynamics of virus genetic diversity using sample date information and sequence data. This type of framework, termed "phylodynamics," helps connect some of the missing links on viral transmission networks, which are often hard to detect by conventional methods of epidemiology. With sufficient number of sequences available, one can use this new inference method to estimate theoretical epidemiological parameters such as temporal distributions of the primary infection, fluctuation of the pathogen population size, basic reproductive number, and the mean time span of disease infectiousness. Transmission networks estimated by this framework often have the properties of a scale-free network, which are characteristic of infectious and social communication processes. Network analysis based on phylodynamics has alluded to various suggestions concerning the infection dynamics associated with a given community and/or risk behavior. In this review, I will summarize the current methods available for identifying the transmission network using phylogeny, and present an argument on the possibilities of applying the scale-free properties to these existing frameworks. PMID:22993510

Shiino, Teiichiro

2012-07-31

196

Viral membrane scission.  

PubMed

Virus budding is a complex, multistep process in which viral proteins make specific alterations in membrane curvature. Many different viral proteins can deform the membrane and form a budding virion, but very few can mediate membrane scission to complete the budding process. As a result, enveloped viruses have developed numerous ways of facilitating membrane scission, including hijacking host cellular scission machinery and expressing their own scission proteins. These proteins mediate scission in very different ways, though the biophysical mechanics underlying their actions may be similar. In this review, we explore the mechanisms of membrane scission and the ways in which enveloped viruses use these systems to mediate the release of budding virions. PMID:24099087

Rossman, Jeremy S; Lamb, Robert A

2013-05-31

197

Prevention of viral hepatitis  

Microsoft Academic Search

Opinion statement  Despite the availability of vaccines against hepatitis A and B, acute viral hepatitis due to these agents continues to be\\u000a among the most commonly reported notifiable infectious diseases in the United States. Currently available hepatitis A and\\u000a B vaccines are highly immunogenic and well tolerated, but vaccine coverage needs to be expanded. Use of the hepatitis A vaccine\\u000a in

Raymond S. Koff

2002-01-01

198

Viral otitis media  

Microsoft Academic Search

Acute otitis media (AOM) and viral upper respiratory tract infections (URIs) represent the two most common diseases affecting\\u000a the human population, and account for substantial patient morbidity and health care costs. Epidemiologic and experimental\\u000a studies suggest that URIs play a causal role in the pathogenesis of AOM. Specifically, viruses can either invade the middle\\u000a ear (ME) space and invoke an

Craig A. Buchman; George M. Brinson

2003-01-01

199

Vaccines 87, modern approaches to new vaccines: Prevention of AIDS and other viral, bacterial and parasitic diseases  

SciTech Connect

This book contains five sections and a summary. Each section consists of several papers. The section titles are: Immunology, AIDS, Pathogenic Bacteria and Viral Glycoproteins, Pathogenesis and Attenuation, and Recombinant Vectors and Paraviruses.

Chanock, R.M.; Lerner, R.A.; Brown, F.; Ginsberg, H.

1987-01-01

200

Autoimmune disease: A role for new anti-viral therapies?  

PubMed

Many chronic human diseases may have an underlying autoimmune mechanism. In this review, the author presents a case of autoimmune CIU (chronic idiopathic urticaria) in stable remission after therapy with a retroviral integrase inhibitor, raltegravir (Isentress). Previous reports located using the search terms "autoimmunity" and "anti-viral" and related topics in the pubmed data-base are reviewed suggesting that novel anti-viral agents such as retroviral integrase inhibitors, gene silencing therapies and eventually vaccines may provide new options for anti-viral therapy of autoimmune diseases. Cited epidemiologic and experimental evidence suggests that increased replication of epigenomic viral pathogens such as Epstein-Barr Virus (EBV) in chronic human autoimmune diseases such as rheumatoid arthritis (RA), systemic lupus Erythematosus (SLE), and multiple sclerosis (MS) may activate endogenous human retroviruses (HERV) as a pathologic mechanism. Memory B cells are the reservoir of infection of EBV and also express endogenous retroviruses, thus depletion of memory b-lymphocytes by monoclonal antibodies (Rituximab) may have therapeutic anti-viral effects in addition to effects on B-lymphocyte presentation of both EBV and HERV superantigens. Other novel anti-viral therapies of chronic autoimmune diseases, such as retroviral integrase inhibitors, could be effective, although not without risk. PMID:21871974

Dreyfus, David H

2011-08-18

201

Viral Discovery and Sequence Recovery Using DNA Microarrays  

PubMed Central

Because of the constant threat posed by emerging infectious diseases and the limitations of existing approaches used to identify new pathogens, there is a great demand for new technological methods for viral discovery. We describe herein a DNA microarray-based platform for novel virus identification and characterization. Central to this approach was a DNA microarray designed to detect a wide range of known viruses as well as novel members of existing viral families; this microarray contained the most highly conserved 70mer sequences from every fully sequenced reference viral genome in GenBank. During an outbreak of severe acute respiratory syndrome (SARS) in March 2003, hybridization to this microarray revealed the presence of a previously uncharacterized coronavirus in a viral isolate cultivated from a SARS patient. To further characterize this new virus, approximately 1 kb of the unknown virus genome was cloned by physically recovering viral sequences hybridized to individual array elements. Sequencing of these fragments confirmed that the virus was indeed a new member of the coronavirus family. This combination of array hybridization followed by direct viral sequence recovery should prove to be a general strategy for the rapid identification and characterization of novel viruses and emerging infectious disease.

2003-01-01

202

IRGM in autophagy and viral infections.  

PubMed

Autophagy is a cell autonomous process allowing each individual cell to fight intracellular pathogens. Autophagy can destroy pathogens within the cytosol, and can elicit innate and adaptive immune responses against microorganisms. Nevertheless, numerous pathogens have developed molecular strategies enabling them to avoid or even exploit autophagy for their own benefit. IRGM (immunity-related GTPase family M) is a human protein recently highlighted for its contribution to autophagy upon infections. The physical association of IRGM with mitochondria and different autophagy-regulating proteins, ATG5, ATG10, SH3GLB1, and LC3, contribute to explain how IRGM could regulate autophagy. Whereas IRGM is involved in autophagy-mediated immunity against bacteria, certain viruses seem to have developed strategies to manipulate autophagy through the selective targeting of this protein. Furthermore, irgm variants are linked to infection-associated human pathologies such as the inflammatory Crohn's disease. Here, we discuss how IRGM might contribute to human autophagy upon viral infection, and why its targeting might be beneficial to virus replication. PMID:23335927

Petkova, Denitsa S; Viret, Christophe; Faure, Mathias

2013-01-17

203

IRGM in autophagy and viral infections  

PubMed Central

Autophagy is a cell autonomous process allowing each individual cell to fight intracellular pathogens. Autophagy can destroy pathogens within the cytosol, and can elicit innate and adaptive immune responses against microorganisms. Nevertheless, numerous pathogens have developed molecular strategies enabling them to avoid or even exploit autophagy for their own benefit. IRGM (immunity-related GTPase family M) is a human protein recently highlighted for its contribution to autophagy upon infections. The physical association of IRGM with mitochondria and different autophagy-regulating proteins, ATG5, ATG10, SH3GLB1, and LC3, contribute to explain how IRGM could regulate autophagy. Whereas IRGM is involved in autophagy-mediated immunity against bacteria, certain viruses seem to have developed strategies to manipulate autophagy through the selective targeting of this protein. Furthermore, irgm variants are linked to infection-associated human pathologies such as the inflammatory Crohn’s disease. Here, we discuss how IRGM might contribute to human autophagy upon viral infection, and why its targeting might be beneficial to virus replication.

Petkova, Denitsa S.; Viret, Christophe; Faure, Mathias

2013-01-01

204

Detection of viral sequences in semen of honeybees ( Apis mellifera): Evidence for vertical transmission of viruses through drones  

Microsoft Academic Search

Honeybees (Apis mellifera) can be attacked by many eukaryotic parasites, and bacterial as well as viral pathogens. Especially in combination with the ectoparasitic mite Varroa destructor, viral honeybee diseases are becoming a major problem in apiculture, causing economic losses worldwide. Several horizontal transmission routes are described for some honeybee viruses. Here, we report for the first time the detection of

Constanze Yue; Marion Schröder; Kaspar Bienefeld; Elke Genersch

2006-01-01

205

Pathomorphological and immunohistological findings in cattle experimentally infected with rinderpest virus isolates of different pathogenicity  

Microsoft Academic Search

Experimental infection of nine cattle with seven rinderpest virus strains of different pathogenicity resulted in significant variations of clinical signs, morphological lesions and distribution of viral antigen in tissues. The severity of clinical disease was correlated with the extent of tissue alterations and the amount of immunohistologically detectable viral antigen. Both mild and virulent strains of rinderpest share essentially the

P. Wohlsein; H. M. Wamwayi; G. Trautwein; J. Pohlenz; B. Liess; T. Barrett

1995-01-01

206

Point, Counterpoint: The Evolution of Pathogenic Viruses and their Human Hosts  

Microsoft Academic Search

Viralpathogensplayaprominentroleinhumanhealthowingtotheir ability to rapidly evolve creative new ways to exploit their hosts. As elegant and deceptive as many viral adaptations are, humans and their ancestors have repeatedly answered their call with equally im- pressive adaptations. Here we argue that the coevolutionary arms race between humans and their viral pathogens is one of the most important forces in human molecular evolution,

Michael Worobey; Adam Bjork; Joel O. Wertheim

2007-01-01

207

Immune evasion by pathogens of bovine respiratory disease complex.  

PubMed

Bovine respiratory tract disease is a multi-factorial disease complex involving several viruses and bacteria. Viruses that play prominent roles in causing the bovine respiratory disease complex include bovine herpesvirus-1, bovine respiratory syncytial virus, bovine viral diarrhea virus and parinfluenza-3 virus. Bacteria that play prominent roles in this disease complex are Mannheimia haemolytica and Mycoplasma bovis. Other bacteria that infect the bovine respiratory tract of cattle are Histophilus (Haemophilus) somni and Pasteurella multocida. Frequently, severe respiratory tract disease in cattle is associated with concurrent infections of these pathogens. Like other pathogens, the viral and bacterial pathogens of this disease complex have co-evolved with their hosts over millions of years. As much as the hosts have diversified and fine-tuned the components of their immune system, the pathogens have also evolved diverse and sophisticated strategies to evade the host immune responses. These pathogens have developed intricate mechanisms to thwart both the innate and adaptive arms of the immune responses of their hosts. This review presents an overview of the strategies by which the pathogens suppress host immune responses, as well as the strategies by which the pathogens modify themselves or their locations in the host to evade host immune responses. These immune evasion strategies likely contribute to the failure of currently-available vaccines to provide complete protection to cattle against these pathogens. PMID:18218162

Srikumaran, Subramaniam; Kelling, Clayton L; Ambagala, Aruna

2007-12-01

208

MicrobPad MD: microbial pathogen diagnostic methods database.  

PubMed

Medical pathogens induce infections, illnesses and sometimes serious medical conditions in the infected hosts. Diagnosis of these pathogens is important for proper treatment and investigation of pathogenesis processes. Molecular techniques have been developed for facilitating accurate, sensitive and low-cost diagnosis of these pathogens. Based on these techniques, diagnostic devices have been developed for a number of pathogens. More devices are needed for comprehensive coverage of medical pathogens. To facilitate the development of these devices, a database with integrated information about diagnostic methods, targets, and primers/probes for the known bacterial, fungal and viral pathogens is needed. We developed the microbial pathogen diagnostic methods database MicrobPad MD (http://bidd.nus.edu.sg/group/MicrobPad/MicrobPad.asp or http://pha-bidd.nus.edu.sg/group/MicrobPad/MicrobPad.asp) to provide comprehensive information about the molecular diagnostic techniques, targets, primers/probes, detection procedures and conditions, and tested diagnostic accuracies and limit of diagnosis for 314 bacterial, fungal and viral species from 61 genera. While available, additional information such as pathogen strains and hosts, tissue distribution or habitats, cultivation methods, biochemical characteristics, virulence factors, morphology, diseases, symptoms, treatment and prevention methods are provided. Our Database covers 242 gene targets, 700 primers/probes, 340 virulence factors, and 261 diseases. Cross-links to the NCBI genome and SwissProt/UniProt databases are provided. PMID:23178820

Han, B C; Wei, X N; Zhang, J X; Truong, N Q T; Westgate, C L; Zhao, R Y; Chen, Y Z

2012-11-21

209

[Viral exanthematic childhood diseases].  

PubMed

Exanthem is defined as multiple, inflammatory skin alteration with a hematogenic, lymphogenic or neurogenic origin. Typically, so called exanthematic children's diseases are measles, mumps, rubella, varicella, erythema infectiosum (fifth disease) and in the past small pox. The pathogenesis of the viral-caused diseases primarily occurs in the vascular connective tissue. The cytopathogenetic effects result in inflammatory tissue reactions with activation of defence mechanism and producing of immune complexes. First symptoms are hyperemia, edema and inflammatory infiltrates with itchy swellings. Virological laboratory diagnosis are necessary especially for the progress of atypical infectious diseases, for persons with immunological or chronical illness and under chemotherapeutical or immunosuppressival treatment. PMID:9471842

Allwinn, R; Doerr, H W

1997-01-01

210

Viral vaccine composition, process and methods of use  

US Patent & Trademark Office Database

A composition for treating or preventing virus-induced infections is described, along with a process of producing the composition and methods of the composition's use. The composition comprises viral pathogen-infected cell or tissue, or malignantly or immunologically aberrant cells or tissues which has been reduced and/or denatured. The preferred composition is administered across a mucosal surface of an animal suffering or about suffer from infection. The composition is administered as preventive or therapeutic vaccine.

Jirathitikal; Vichai (Chachoengsao, TH); Bourinbaiar; Aldar (College Park, MD)

2010-11-23

211

Viral hepatitis in Bucharest.  

PubMed

A seroprevalence survey of viral hepatitis was conducted in Bucharest, Romania, between April and July 1990 on a systematic sample of 1355 persons drawn from the general population and groups at higher risk of infection. Sera were tested for hepatitis A, B, and C (HAV, HBV and HCV, resp.) markers using an enzyme-linked immunosorbent assay (ELISA) method. The prevalences of HAV and HBV markers were high in all groups. A total of 47% of the adults from the general population and 39.8% of the children aged 0-16 years had at least one HBV marker. Of the pregnant women 7.8% were positive for hepatitis B surface antigen. Among infants (0-3 years of age) living in orphanages, the prevalence of at least one HBV marker was 54.6%. The findings also confirmed that HCV was circulating in Romania. The results are consistent with national surveillance data and confirm that viral hepatitis is a major public health problem in Romania. Preventive measures will have to include HBV immunization of infants, with an appropriately targeted immunization strategy being determined through further epidemiological studies. PMID:8313496

Paquet, C; Babes, V T; Drucker, J; Sénémaud, B; Dobrescu, A

1993-01-01

212

Viral hemorrhagic fevers.  

PubMed

A taxonomically diverse set of single-stranded ribonucleic acid(ssRNA) viruses from four diverse viral families Arenaviridae,Bunyaviridae, Filoviridae, and Flaviviridae cause an acute systemic febrile syndrome called viral hemorrhagic fever (VHF). The syndrome produces combinations of prostration, malaise, increased vascular permeability, and coagulation maladies. In severe illness,VHF may include generalized bleeding but the bleeding does not typically constitute a life-threatening loss of blood volume. To a certain extent, it is a sign of damage to the vascular endothelium and is an indicator of disease severity in specific target organs. Although the viruses that cause hemorrhagic fever (HF) can productively replicate in endothelial cells, much of the disease pathology including impairment to the vascular system is thought to result primarily from the release of a variety of mediators from virus-infected cells, such as monocytes and macrophages that subsequently alter vascular function and trigger the coagulation disorders that epitomize these infections. While significant progress has been made over the last several years in dissecting out the molecular biology and pathogenesis of the HF viruses, there are currently no vaccines or drugs licensed available for most of the VHFs. PMID:16815457

Marty, Aileen M; Jahrling, Peter B; Geisbert, Thomas W

2006-06-01

213

Purifying selection can obscure the ancient age of viral lineages.  

PubMed

Statistical methods for molecular dating of viral origins have been used extensively to infer the time of most common recent ancestor for many rapidly evolving pathogens. However, there are a number of cases, in which epidemiological, historical, or genomic evidence suggests much older viral origins than those obtained via molecular dating. We demonstrate how pervasive purifying selection can mask the ancient origins of recently sampled pathogens, in part due to the inability of nucleotide-based substitution models to properly account for complex patterns of spatial and temporal variability in selective pressures. We use codon-based substitution models to infer the length of branches in viral phylogenies; these models produce estimates that are often considerably longer than those obtained with traditional nucleotide-based substitution models. Correcting the apparent underestimation of branch lengths suggests substantially older origins for measles, Ebola, and avian influenza viruses. This work helps to reconcile some of the inconsistencies between molecular dating and other types of evidence concerning the age of viral lineages. PMID:21705379

Wertheim, Joel O; Kosakovsky Pond, Sergei L

2011-06-24

214

Complete viral RNA genome sequencing of ultra-low copy samples by sequence-independent amplification  

PubMed Central

RNA viruses are the causative agents for AIDS, influenza, SARS, and other serious health threats. Development of rapid and broadly applicable methods for complete viral genome sequencing is highly desirable to fully understand all aspects of these infectious agents as well as for surveillance of viral pandemic threats and emerging pathogens. However, traditional viral detection methods rely on prior sequence or antigen knowledge. In this study, we describe sequence-independent amplification for samples containing ultra-low amounts of viral RNA coupled with Illumina sequencing and de novo assembly optimized for viral genomes. With 5 million reads, we capture 96 to 100% of the viral protein coding region of HIV, respiratory syncytial and West Nile viral samples from as little as 100 copies of viral RNA. The methods presented here are scalable to large numbers of samples and capable of generating full or near full length viral genomes from clone and clinical samples with low amounts of viral RNA, without prior sequence information and in the presence of substantial host contamination.

Malboeuf, Christine M.; Yang, Xiao; Charlebois, Patrick; Qu, James; Berlin, Aaron M.; Casali, Monica; Pesko, Kendra N.; Boutwell, Christian L.; DeVincenzo, John P.; Ebel, Gregory D.; Allen, Todd M.; Zody, Michael C.; Henn, Matthew R.; Levin, Joshua Z.

2013-01-01

215

Analysis of Viral Load in Children Infected with Human Metapneumovirus  

PubMed Central

Objective Human metapneumovirus (hMPV) is a respiratory pathogen responsible for disease and subsequent hospitalizations in young children around the world. The disease pathology, including how viral load correlates with respiratory disease severity, remains unclear. This study investigated the correlation between viral load and clinical characteristics of hMPV infections. Methods Nasopharyngeal aspirate (NPA) samples collected from 18 infants hospitalized for lower respiratory tract infections (LRTIs) in winter were tested for hMPV by reverse transcriptase polymerase chain reaction (RT-PCR) and real-time RT-PCR. Their NPA samples were collected every-other-day to monitor changes in hMPV viral load during hospitalization. Also all these 18 patients were monitored to characterize clinically their illness. Findings hMPV load was not correlated with infection severity (P=0.5, 0.9, 0.5). In contrast, the log10 of hMPV viral load was significantly different between those lasted for 6–11 days and those for less than 5 days (P=0.01), also the significant difference was shown between those of 6–11 days duration and those of more than 11 days (P=0.006), but there was no significant difference between those lasted for less than 5 days and those for more than 11 days (P=0.4). Additionally, high hMPV viral shedding occured between 6 and 11days. Conclusion hMPV load was significantly correlated with the course of illness. The association between hMPV viral load and the course of disease suggested that hMPV is an important pathogen in lower respiratory tract infection in children. But hMPV did not always lead to more severe respiratory illness.

Peng, Donghong; Zhao, Xiaodong; Liu, Enmei; Huang, Ying; Yang, Xiqiang; Zhao, Yao; Chen, Xin; Zhang, Zhiyong

2010-01-01

216

Host and viral ecology determine bat rabies seasonality and maintenance  

USGS Publications Warehouse

Rabies is an acute viral infection that is typically fatal. Most rabies modeling has focused on disease dynamics and control within terrestrial mammals (e.g., raccoons and foxes). As such, rabies in bats has been largely neglected until recently. Because bats have been implicated as natural reservoirs for several emerging zoonotic viruses, including SARS-like corona viruses, henipaviruses, and lyssaviruses, understanding how pathogens are maintained within a population becomes vital. Unfortunately, little is known about maintenance mechanisms for any pathogen in bat populations. We present a mathematical model parameterized with unique data from an extensive study of rabies in a Colorado population of big brown bats (Eptesicus fuscus) to elucidate general maintenance mechanisms. We propose that life history patterns of many species of temperate-zone bats, coupled with sufficiently long incubation periods, allows for rabies virus maintenance. Seasonal variability in bat mortality rates, specifically low mortality during hibernation, allows long-term bat population viability. Within viable bat populations, sufficiently long incubation periods allow enough infected individuals to enter hibernation and survive until the following year, and hence avoid an epizootic fadeout of rabies virus. We hypothesize that the slowing effects of hibernation on metabolic and viral activity maintains infected individuals and their pathogens until susceptibles from the annual birth pulse become infected and continue the cycle. This research provides a context to explore similar host ecology and viral dynamics that may explain seasonal patterns and maintenance of other bat-borne diseases.

George, D. B.; Webb, C. T.; Farnsworth, M. L.; O'Shea, T. J.; Bowen, R. A.; Smith, D. L.; Stanley, T. R.; Ellison, L. E.; Rupprecht, C. E.

2011-01-01

217

Influenza and endemic viral pneumonia.  

PubMed

Viruses are a common and important cause of severe community-acquired pneumonia, and may lead to severe respiratory disease and admission to the intensive care unit. Influenza is the most common virus associated with severe viral pneumonia, although other important causes include respiratory syncytial virus, adenovirus, metapneumonia virus, and coronaviruses. Viral pneumonias tend to have a seasonal predilection and are often preceded by a typical viral prodrome. This article focuses on severe influenza pneumonia, including the 2009 H1N1 pandemic, and briefly discusses other causes of severe respiratory disease of viral etiology. PMID:24094391

Ramsey, Clare D; Kumar, Anand

2013-10-01

218

Update on pathogen reduction technology for therapeutic plasma: An overview  

Microsoft Academic Search

Human plasma for therapeutic use, besides having optimal viral safety, must contain optimal levels of all coagulation factors and protease inhibitors to be clinically effective. Several new technologies for pathogen reduction of plasma (PRT) exist and are entering the stage of clinical testing. The main objective of this overview is to provide an update on the current states of three

B. G. Solheim; J. Seghatchian

2006-01-01

219

Viral hepatitis in India.  

PubMed

Viral hepatitis is a major public health problem in India, which is hyperendemic for HAV and HEV. Seroprevalence studies reveal that 90%-100% of the population acquires anti-HAV antibody and becomes immune by adolescence. Many epidemics of HEV have been reported from India. HAV related liver disease is uncommon in India and occurs mainly in children. HEV is also the major cause of sporadic adult acute viral hepatitis and ALF. Pregnant women and patients with CLD constitute the high risk groups to contract HEV infection, and HEV-induced mortality among them is substantial, which underlines the need for preventive measures for such groups. Children with HAV and HEV coinfection are prone to develop ALF. India has intermediate HBV endemicity, with a carrier frequency of 2%-4%. HBV is the major cause of CLD and HCC. Chronic HBV infection in India is acquired in childhood, presumably before 5 years of age, through horizontal transmission. Vertical transmission of HBV in India is considered to be infrequent. Inclusion of HBV vaccination in the expanded programme of immunization is essential to reduce the HBV carrier frequency and disease burden. HBV genotypes A and D are prevalent in India, which are similar to the HBV genotypes in the West. HCV infection in India has a population prevalence of around 1%, and occurs predominantly through transfusion and the use of unsterile glass syringes. HCV genotypes 3 and 2 are prevalent in 60%-80% of the population and they respond well to a combination of interferon and ribavirin. About 10%-15% of CLD and HCC are associated with HCV infection in India. HCV infection is also a major cause of post-transfusion hepatitis. HDV infection is infrequent in India and is present about 5%-10% of patients with HBV-related liver disease. HCC appears to be less common in India than would be expected from the prevalence rates of HBV and HCV. The high disease burden of viral hepatitis and related CLD in India, calls for the setting up of a hepatitis registry and formulation of government-supported prevention and control strategies. PMID:17100109

Acharya, S K; Madan, Kaushal; Dattagupta, S; Panda, S K

220

Viral IRES RNA structures and ribosome interactions.  

PubMed

In eukaryotes, protein synthesis initiates primarily by a mechanism that requires a modified nucleotide 'cap' on the mRNA and also proteins that recruit and position the ribosome. Many pathogenic viruses use an alternative, cap-independent mechanism that substitutes RNA structure for the cap and many proteins. The RNAs driving this process are called internal ribosome-entry sites (IRESs) and some are able to bind the ribosome directly using a specific 3D RNA structure. Recent structures of IRES RNAs and IRES-ribosome complexes are revealing the structural basis of viral IRES' 'hijacking' of the protein-making machinery. It now seems that there are fundamental differences in the 3D structures used by different IRESs, although there are some common features in how they interact with ribosomes. PMID:18468443

Kieft, Jeffrey S

2008-05-28

221

Application of Nucleic-acid-based Therapeutics for Viral Infections in Shrimp Aquaculture  

Microsoft Academic Search

Viral infections are one of the major reasons for the huge economic losses in shrimp farming. The control of viral diseases\\u000a in shrimp remains a serious challenge for the shrimp aquacultural industry, with major pathogens, such as the white spot syndrome\\u000a virus, yellow head virus, Taura syndrome virus, hepatopancreatic parvovirus, and baculoviruses, being geographically widespread.\\u000a In the absence of a

Mudagandur S. Shekhar; Yuanan Lu

2009-01-01

222

Viral Epitopes and Monoclonal Antibodies: Isolation of Blocking Antibodies that Inhibit Virus Neutralization  

NASA Astrophysics Data System (ADS)

The inability of pathogenic animal viruses to be completely neutralized by antibodies can lead to chronic viral infections in which infectious virus persists even in the presence of excess neutralizing antibody. A mechanism that results in this nonneutralized fraction of virus was defined by the topographical relationships of viral epitopes identified with monoclonal antibodies wherein monoclonal antibodies bind to virus and sterically block the binding of neutralizing antibodies.

Massey, Richard J.; Schochetman, Gerald

1981-07-01

223

CD8+ T-cell responses to different HIV proteins have discordant associations with viral load  

Microsoft Academic Search

Selection of T-cell vaccine antigens for chronic persistent viral infections has been largely empirical. To define the relationship, at the population level, between the specificity of the cellular immune response and viral control for a relevant human pathogen, we performed a comprehensive analysis of the 160 dominant CD8+ T-cell responses in 578 untreated HIV-infected individuals from KwaZulu-Natal, South Africa. Of

Photini Kiepiela; Kholiswa Ngumbela; Christina Thobakgale; Dhanwanthie Ramduth; Isobella Honeyborne; Eshia Moodley; Shabashini Reddy; Chantal de Pierres; Zenele Mncube; Nompumelelo Mkhwanazi; Karen Bishop; Mary van der Stok; Kriebashnie Nair; Nasreen Khan; Hayley Crawford; Rebecca Payne; Alasdair Leslie; Julia Prado; Andrew Prendergast; John Frater; Noel McCarthy; Christian Brander; Gerald H Learn; David Nickle; Christine Rousseau; Hoosen Coovadia; James I Mullins; David Heckerman; Bruce D Walker; Philip Goulder

2006-01-01

224

Molecular Determinants of Virulence, Cell Tropism, and Pathogenic Phenotype of Infectious Bursal Disease Virus  

Microsoft Academic Search

Infectious bursal disease viruses (IBDVs), belonging to the family Birnaviridae, exhibit a wide range of immunosuppressive potential, pathogenicity, and virulence for chickens. The genomic segment A encodes all the structural (VP2, VP4, and VP3) and nonstructural proteins, whereas segment B encodes the viral RNA- dependent RNA polymerase (VP1). To identify the molecular determinants for the virulence, pathogenic phenotype, and cell

MEGGIN BRANDT; KUN YAO; MEIHONG LIU; ROBERT A. HECKERT; VIKRAM N. VAKHARIA

2001-01-01

225

Characterization of an Antigenic Determinant of the Glycoprotein That Correlates with Pathogenicity of Rabies Virus  

Microsoft Academic Search

The pathogenicity of fixed rabies virus strains for adult mice depends on the presence of an antigenic determinant on the viral glycoprotein. Two virus-neutralizing monoclonal antibodies have been used to identify this determinant. All pathogenic strains of fixed rabies virus bind to these antibodies and are neutralized by them, whereas nonpathogenic strains fail to react with these monoclonal antibodies and

Bernhard Dietzschold; William H. Wunner; Tadeusz J. Wiktor; A. Dwight Lopes; Monique Lafon; Carolyn L. Smith; Hilary Koprowski

1983-01-01

226

Molecular approaches to detecting and discriminating among prions, a class of pathogenic molecules(Abstract)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Prions (PrPSc)are the pathogens that cause a set of fatal neurological diseases that include scrapie and chronic wasting disease (CWD). They are composed solely of protein and unlike viral, bacterial, or fungal pathogens, the information necessary to convert the normal cellular prion protein (PrPC) ...

227

Therapy of viral hepatitis.  

PubMed

Worldwide viral hepatitis is the most common cause of jaundice, chronic liver disease cirrhosis and hepatocellular carcinoma. While important advances have been made in prevention of viral hepatitis, therapy of this disease remains unsatisfactory. There are no specific therapies of proven benefit for acute hepatitis, although use of alpha-interferon during the acute phase of hepatitis C may result in a decrease in the rate of chronicity. For chronic viral hepatitis, alpha-interferon has been widely used, but is expensive, poorly tolerated and limited in effectiveness. New antiviral agents and use of combinations of antivirals are now being evaluated and promise to provide a therapy that is effective in the majority of patients. The currently recommended therapy of chronic hepatitis B is a 4- to 6-month course of alpha-interferon in doses of 5-10 million units three times a week; a regimen that results in sustained clearance of hepatitis B virus (HBV) DNA and hepatitis B e antigen (HBeAg) from serum in approximately one-third and a loss of hepatitis B surface antigen (HBsAg) in one-tenth of patients. Long-term follow-up of patients who respond to interferon treatment with clearance of HBeAg indicate that the majority ultimately clear HBsAg as well and have continued remission in the liver disease, although low levels of HBV DNA can commonly be detected in liver tissue. Better therapies of hepatitis B are needed. Recently, several oral 'second-generation' nucleoside analogues have been developed that have potent activity against HBV. The best studied is lamivudine (3-thiacytidine) which results in marked inhibition of HBV DNA levels and improvement in serum aminotransferases and hepatic histology in the majority of patients. When stopped, however, most patients relapse and the shortcomings of long-term therapy have been the development of viral resistance in up to one-quarter of patients within a year and a higher percentage with more prolonged therapy. Future approaches of therapy of promise for hepatitis B are combinations of lamivudine with interferon and other antiviral nucleoside analogues. The currently recommended therapy of chronic hepatitis C is a 12- to 18-month course of alpha interferon in doses of 3 million units three times a week: a regimen that results in sustained clearance of hepatitis C virus (HCV) RNA in approximately 20% of patients. Sustained responses have been associated with marked improvements in hepatic histology and long-term studies indicate that the majority of patients remain free of virus in serum and liver, suggesting a 'cure' of infection. Responses to interferon correlate to some degree with clinical and virological features, including young age, absence of hepatic fibrosis, low levels of HCV RNA in serum and HCV genotypes 2 and 3. (ABSTRACT TRUNCATED) PMID:9705540

Hoofnagle, J H

1998-08-01

228

Enteric pathogens through life stages  

PubMed Central

Enteric infections and diarrheal diseases constitute pervasive health burdens throughout the world, with rates being highest at the two ends of life. During the first 2–3 years of life, much of the disease burden may be attributed to infection with enteric pathogens including Salmonella, rotavirus, and many other bacterial, viral, and protozoan organisms; however, infections due to Clostridium difficile exhibit steady increases with age. Still others, like Campylobacter infections in industrialized settings are high in early life (<2 years old) and increase again in early adulthood (called the “second weaning” by some). The reasons for these differences undoubtedly reside in part in pathogen differences; however, host factors including the commensal intestinal microbial communities, immune responses (innate and acquired), and age-dependant shifts likely play important roles. Interplay of these factors is illustrated by studies examining changes in human gut microbiota with inflammatory bowel disease and irritable bowel syndrome. Recent gut microbial surveys have indicated dramatic shifts in gut microbial population structure from infants to young adults to the elders. An understanding of the evolution of these factors and their interactions (e.g., how does gut microbiota modulate the “inflamm-aging” process or vice versa) through the human life “cycle” will be important in better addressing and controlling these enteric infections and their consequences for both quality and quantity of life (often assessed as disability adjusted life-years or “DALYs”).

Kolling, Glynis; Wu, Martin; Guerrant, Richard L.

2012-01-01

229

Moraxella catarrhalis - pathogen or commensal?  

PubMed

Moraxella catarrhalis is an exclusively human commensal and mucosal pathogen. Its role as a disease-causing organism has long been questioned. Today, it is recognized as one of the major causes of acute otitis media in children, and its relative frequency of isolation from both the nasopharynx and the middle ear cavity has increased since the introduction of the heptavalent pneumococcal conjugate vaccine, which is associated with a shift in the composition of the nasopharyngeal flora in infants and young children. Although otitis media caused by M. catarrhalis is generally believed to be mild in comparison with pneumococcal disease, numerous putative virulence factors have now been identified and it has been shown that several surface components of M. catarrhalis induce mucosal inflammation. In adults with chronic obstructive pulmonary disease (COPD), M. catarrhalis is now a well-established trigger of approximately 10% of acute inflammatory exacerbations.Although the so-called cold shock response is a well-described bacterial stress response in species such as Escherichia coli, Bacillus subtilis or - more recently - Staphylococcus aureus, M. catarrhalis is the only typical nasopharyngeal pathogen in which this response has been investigated. Indeed, a 3-h 26°C cold shock, which may occur physiologically, when humans inspire cold air for prolonged periods of time, increases epithelial cell adherence and enhances proinflammatory host responses and may thus contribute to the symptoms referred to as common cold, which typically are attributed to viral infections. PMID:21120723

Aebi, Christoph

2011-01-01

230

A Strategy To Estimate Unknown Viral Diversity in Mammals  

PubMed Central

ABSTRACT The majority of emerging zoonoses originate in wildlife, and many are caused by viruses. However, there are no rigorous estimates of total viral diversity (here termed “virodiversity”) for any wildlife species, despite the utility of this to future surveillance and control of emerging zoonoses. In this case study, we repeatedly sampled a mammalian wildlife host known to harbor emerging zoonotic pathogens (the Indian Flying Fox, Pteropus giganteus) and used PCR with degenerate viral family-level primers to discover and analyze the occurrence patterns of 55 viruses from nine viral families. We then adapted statistical techniques used to estimate biodiversity in vertebrates and plants and estimated the total viral richness of these nine families in P. giganteus to be 58 viruses. Our analyses demonstrate proof-of-concept of a strategy for estimating viral richness and provide the first statistically supported estimate of the number of undiscovered viruses in a mammalian host. We used a simple extrapolation to estimate that there are a minimum of 320,000 mammalian viruses awaiting discovery within these nine families, assuming all species harbor a similar number of viruses, with minimal turnover between host species. We estimate the cost of discovering these viruses to be ~$6.3 billion (or ~$1.4 billion for 85% of the total diversity), which if annualized over a 10-year study time frame would represent a small fraction of the cost of many pandemic zoonoses.

Anthony, Simon J.; Epstein, Jonathan H.; Murray, Kris A.; Navarrete-Macias, Isamara; Zambrana-Torrelio, Carlos M.; Solovyov, Alexander; Ojeda-Flores, Rafael; Arrigo, Nicole C.; Islam, Ariful; Ali Khan, Shahneaz; Hosseini, Parviez; Bogich, Tiffany L.; Olival, Kevin J.; Sanchez-Leon, Maria D.; Karesh, William B.; Goldstein, Tracey; Luby, Stephen P.; Morse, Stephen S.; Mazet, Jonna A. K.; Daszak, Peter; Lipkin, W. Ian

2013-01-01

231

Sudden Deafness: Is It Viral?  

Microsoft Academic Search

A number of theories have been proposed to explain the etiopathogenesis of idiopathic sudden sensorineural hearing loss (ISSHL), including viral infection, vascular occlusion, breaks of labyrinthine membranes, immune-mediated mechanisms and abnormal cellular stress responses within the cochlea. In the present paper, we provide a critical review of the viral hypothesis of ISSHL. The evidence reviewed includes published reports of epidemiological

Saumil N. Merchant; Marlene L. Durand; Joe C. Adams

2008-01-01

232

Pathogenic simian immunodeficiency virus infection is associated with expansion of the enteric virome  

PubMed Central

SUMMARY Pathogenic simian immunodeficiency virus (SIV) infection is associated with enteropathy which likely contributes to AIDS progression. To identify candidate etiologies for AIDS enteropathy, we used next generation sequencing to define the enteric virome during SIV infection in nonhuman primates. Pathogenic, but not non-pathogenic, SIV infection was associated with significant expansion of the enteric virome. We identified at least 32 previously undescribed enteric viruses during pathogenic SIV infection and confirmed their presence using viral culture and PCR testing. We detected unsuspected mucosal adenovirus infection associated with enteritis as well as parvovirus viremia in animals with advanced AIDS, indicating the pathogenic potential of SIV-associated expansion of the enteric virome. No association between pathogenic SIV infection and the family-level taxonomy of enteric bacteria was detected. Thus, enteric viral infections may contribute to AIDS enteropathy and disease progression. These findings underline the importance of metagenomic analysis of the virome for understanding AIDS pathogenesis.

Handley, Scott; Thackray, Larissa B.; Zhao, Guoyan; Presti, Rachel; Miller, Andrew; Droit, Lindsay; Abbink, Peter; Maxfield, Lori F.; Kambal, Amal; Duan, Erning; Stanley, Kelly; Kramer, Joshua; Macri, Sheila C.; Permar, Sallie R.; Schmitz, Joern E.; Mansfield, Keith; Brenchley, Jason M.; Veazey, Ronald S.; Stappenbeck, Thaddeus S.; Wang, David; Barouch, Dan H.; Virgin, Herbert W.

2012-01-01

233

Pathogen Chip for Respiratory Tract Infections  

PubMed Central

Determining the viral etiology of respiratory tract infections (RTI) has been limited for the most part to specific primer PCR-based methods due to their increased sensitivity and specificity compared to other methods, such as tissue culture. However, specific primer approaches have limited the ability to fully understand the diversity of infecting pathogens. A pathogen chip system (PathChip), developed at the Genome Institute of Singapore (GIS), using a random-tagged PCR coupled to a chip with over 170,000 probes, has the potential to recognize all known human viral pathogens. We tested 290 nasal wash specimens from Filipino children <2 years of age with respiratory tract infections using culture and 3 PCR methods—EraGen, Luminex, and the GIS PathChip. The PathChip had good diagnostic accuracy, ranging from 85.9% (95% confidence interval [CI], 81.3 to 89.7%) for rhinovirus/enteroviruses to 98.6% (95% CI, 96.5 to 99.6%) for PIV 2, compared to the other methods and additionally identified a number of viruses not detected by these methods.

Patel, Champa; Sung, Wing-Kin; Lee, Charlie W. H.; Loh, Kuan Hon; Lucero, Marilla; Nohynek, Hanna; Nai, Geraldine; Thien, Pei Ling; Koh, Chee Wee; Chan, Yang Sun; Ma, Jianmin; Maurer-Stroh, Sebastian; Carosone-Link, Phyllis; Hibberd, Martin L.; Wong, Christopher W.

2013-01-01

234

Comparison of pathogenic domains of rabies and African rabies-related lyssaviruses and pathogenicity observed in mice.  

PubMed

Several lyssavirus species occur in Africa (Rabies virus, Lagos bat virus, Mokola virus, Duvenhage virus, Shimoni bat virus and Ikoma lyssavirus), displaying a high sequence diversity between isolates belonging to the same species. There is limited information about comparative pathogenesis of these African lyssaviruses and this precludes authoritative opinion on the potential public and veterinary health impact. In this study, an analysis of representative African lyssaviruses attempted to correlate viral genomic sequence similarities and differences with the corresponding pathogenic profiles observed in mice. The study demonstrated that the virus isolates evaluated could be lethal to mice when introduced intramuscularly and that different isolates of the same lyssavirus species differ in their virulence. Using real-time polymerase chain reaction (PCR), viral RNA was detected in brain tissue, but no viral RNA was detected in the salivary glands or blood of mice that succumbed to infection. Comparison of known pathogenic domains indicated that pathogenicity is likely to be dependent on multiple domains. Cumulatively, our results re-emphasised the realisation that the pathogenicity of a lyssavirus species cannot be deduced based on studies of only a single isolate of the species or a single pathogenic domain. PMID:23718883

Kgaladi, Joe; Nel, Louis H; Markotter, Wanda

2013-03-08

235

Metagenomics-based analysis of viral communities in dairy lagoon wastewater.  

PubMed

Microbial populations, especially those of viruses, are poorly studied in dairy wastewater treatment operations. Here we report signature nucleic acid metagenomic sequences obtained by pyrosequencing viromes of virus-like particles that were extracted from two dairy waste treatment lagoons. The lagoons are operated in series, with Lagoon I being used as the primary stage and Lagoon II as the secondary stage of wastewater treatment. An average of 2000 sequences was obtained from each lagoon. More than 300 signatures from each lagoon matched sequences in the virus database of the National Center for Biotechnology Information (NCBI). We utilized a bioinformatics approach and transmission electron microscopy (TEM) to characterize the viral diversity and presence of potential viral pathogens within the lagoons. Our results showed differences in viral community compositions between Lagoon I and Lagoon II, suggesting that the viral community changes significantly in the transition of water between the two lagoons. Furthermore, the diverse viral community in the lagoon samples contained signature sequences of a variety of bacterial, plant, and animal viruses. Bacteriophage sequences dominated the viral community metagenomes in both lagoons. Ultimately these results can be used to identify viral bioindicators to rapidly assess wastewater treatment quality and the potential impacts of dairy operations on watersheds. Our viral metagenomic sequences have been submitted to GenBank (GPID 65805) and can provide insight into the composition and structure of viral communities within wastewaters of dairy lagoon systems. PMID:23220059

Alhamlan, F S; Ederer, M M; Brown, C J; Coats, E R; Crawford, R L

2012-12-04

236

Pathogen Phytosensing: Plants to Report Plant Pathogens  

PubMed Central

Real-time systems that provide evidence of pathogen contamination in crops can be an important new line of early defense in agricultural centers. Plants possess defense mechanisms to protect against pathogen attack. Inducible plant defense is controlled by signal transduction pathways, inducible promoters and cis-regulatory elements corresponding to key genes involved in defense, and pathogen-specific responses. Identified inducible promoters and cis-acting elements could be utilized in plant sentinels, or ‘phytosensors’, by fusing these to reporter genes to produce plants with altered phenotypes in response to the presence of pathogens. Here, we have employed cis-acting elements from promoter regions of pathogen inducible genes as well as those responsive to the plant defense signal molecules salicylic acid, jasmonic acid, and ethylene. Synthetic promoters were constructed by combining various regulatory elements supplemented with the enhancer elements from the Cauliflower mosaic virus (CaMV) 35S promoter to increase basal level of the GUS expression. The inducibility of each synthetic promoter was first assessed in transient expression assays using Arabidopsis thaliana protoplasts and then examined for efficacy in stably transgenic Arabidopsis and tobacco plants. Histochemical and fluorometric GUS expression analyses showed that both transgenic Arabidopsis and tobacco plants responded to elicitor and phytohormone treatments with increased GUS expression when compared to untreated plants. Pathogen-inducible phytosensor studies were initiated by analyzing the sensitivity of the synthetic promoters against virus infection. Transgenic tobacco plants infected with Alfalfa mosaic virus showed an increase in GUS expression when compared to mock-inoculated control plants, whereas Tobacco mosaic virus infection caused no changes in GUS expression. Further research, using these transgenic plants against a range of different pathogens with the regulation of detectable reporter gene could provide biological evidence to define the functional differences between pathogens, and provide new technology and applications for transgenic plants as phytosensors.

Mazarei, Mitra; Teplova, Irina; Hajimorad, M. Reza; Stewart, C. Neal

2008-01-01

237

Host genetic determinants of influenza pathogenicity.  

PubMed

Despite effective vaccines, influenza remains a major global health threat due to the morbidity and mortality caused by seasonal epidemics, as well as the 2009 pandemic. Also of profound concern are the rare but potentially catastrophic transmissions of avian influenza to humans, highlighted by a recent H7N9 influenza outbreak. Murine and human studies reveal that the clinical course of influenza is the result of a combination of both host and viral genetic determinants. While viral pathogenicity has long been the subject of intensive efforts, research to elucidate host genetic determinants, particularly human, is now in the ascendant, and the goal of this review is to highlight these recent insights. PMID:23933004

Lin, Tsai-Yu; Brass, Abraham L

2013-08-08

238

Pattern Recognition Receptors and the Innate Immune Response to Viral Infection  

PubMed Central

The innate immune response to viral pathogens is critical in order to mobilize protective immunity. Cells of the innate immune system detect viral infection largely through germline-encoded pattern recognition receptors (PRRs) present either on the cell surface or within distinct intracellular compartments. These include the Toll-like receptors (TLRs), the retinoic acid-inducble gene I-like receptors (RLRs), the nucleotide oligomerization domain-like receptors (NLRs, also called NACHT, LRR and PYD domain proteins) and cytosolic DNA sensors. While in certain cases viral proteins are the trigger of these receptors, the predominant viral activators are nucleic acids. The presence of viral sensing PRRs in multiple cellular compartments allows innate cells to recognize and quickly respond to a broad range of viruses, which replicate in different cellular compartments. Here, we review the role of PRRs and associated signaling pathways in detecting viral pathogens in order to evoke production of interferons and cytokines. By highlighting recent progress in these areas, we hope to convey a greater understanding of how viruses activate PRR signaling and how this interaction shapes the anti-viral immune response.

Thompson, Mikayla R.; Kaminski, John J.; Kurt-Jones, Evelyn A.; Fitzgerald, Katherine A.

2011-01-01

239

Correlations between Microbial Indicators, Pathogens, and Environmental Factors in a Subtropical Estuary  

PubMed Central

The objective of this study was to evaluate whether indicator microbes and physical-chemical parameters were correlated with pathogens within a tidally influenced estuary. Measurements included the analysis of physical-chemical parameters (pH, salinity, temperature, and turbidity), measurements of bacterial indicators (enterococci, fecal coliform, E. coli, and total coliform), viral indicators (somatic and MS2 coliphage), viral pathogens (enterovirus by culture), and protozoan pathogens (Cryptosporidium and Giardia). All pathogen results were negative with the exception of one sample which tested positive for culturable reovirus (8.5 MPN/100 L).. Notable physical-chemical parameters for this sample included low salinity (<1 ppt) and high water temperature (31 °C). Indicator bacteria and indicator virus levels for this sample were within average values typically measured within the study site and were low in comparison with levels observed in other freshwater environments. Overall results suggest that high levels of bacterial and viral indicators were associated with low salinity sites.

Ortega, Cristina; Solo-Gabriele, Helena M.; Abdelzaher, Amir; Wright, Mary; Deng, Yang; Stark, Lillian M.

2009-01-01

240

[Emerging viral diseases].  

PubMed

Emerging and re-emerging infectious diseases have again entered the public arena in recent years. This is due to factors such as evolving lifestyles, ecological and socio-political upheavals, and recent diagnostic advances. Numerous pathogens, including viruses like West Nile, Chikungunya and Japanese encephalitis on the one hand, and hemorrhagic fever viruses like Ebola and Maburg, are particular concerns. Recently, the Corona virus responsible for SARS, which caused an epidemic sufficiently worrisome to challenge crisis management concepts, was successfully isolated. It is in this context that so-called "bird flu'", may be on the verge of causing a human pandemic. Pox and Monkeypox are "virtually emerging" viruses that have potential for use in bioterrorism. The management and treatment of these emerging infectious diseases calls for new approaches, organizations and infrastructures. PMID:17140098

Bricaire, François; Bossi, Philippe

2006-03-01

241

Viral infection, inflammation and schizophrenia.  

PubMed

Schizophrenia is a severe neurodevelopmental disorder with genetic and environmental etiologies. Prenatal viral/bacterial infections and inflammation play major roles in the genesis of schizophrenia. In this review, we describe a viral model of schizophrenia tested in mice whereby the offspring of mice prenatally infected with influenza at E7, E9, E16, and E18 show significant gene, protein, and brain structural abnormalities postnatally. Similarly, we describe data on rodents exposed to bacterial infection or injected with a synthetic viral mimic (PolyI:C) also demonstrating brain structural and behavioral abnormalities. Moreover, human serologic data has been indispensible in supporting the viral theory of schizophrenia. Individuals born seropositive for bacterial and viral agents are at a significantly elevated risk of developing schizophrenia. While the specific mechanisms of prenatal viral/bacterial infections and brain disorder are unclear, recent findings suggest that the maternal inflammatory response may be associated with fetal brain injury. Preventive and therapeutic treatment options are also proposed. This review presents data related to epidemiology, human serology, and experimental animal models which support the viral model of schizophrenia. PMID:22349576

Kneeland, Rachel E; Fatemi, S Hossein

2012-02-10

242

Papel de los receptores tipo toll en las infecciones virales: el VIH-1 como modelo  

Microsoft Academic Search

The toll-like receptors are an essential component of the innate and adaptive immune response. They are responsible for the recognition of different pathogens agents and trigger responses directed at eliminating the pathogens as well as the development of immunological long-term memory. During viral infections, several different toll-like receptors are activated. These generally induce a protective immune response, but at the

Juan Carlos Hernández; Carlos Julio Montoya; Silvio Urcuqui-Inchima

2007-01-01

243

Viral BLIP dynamics during HAART.  

SciTech Connect

Intermittent episodes of low-level viremia (blips) are often observed in well-suppressed, HAART-treated patients. It has been reported that viral blips do not correlate with the emergence of new HAART-related mutations; however, increased frequency of blips correlates with slower decay of latently infected cells. Since blips are transient and unpredictable, detailed knowledge about them is difficult to obtain. We present an analysis of the dynamics of viral blips from viral load (VL) measurements on 123 patients for a period of 809k480d (21-1817d) and sampled every 31{+-}12d for a total of 26{+-}15 samples per patient.

Markowitz, M.; Louie, M. (Michael); Hurley, A. (Arlene); Ho, David D.; Perelson, Alan S.,; Di Mascio, M. (Michele)

2001-01-01

244

Viruses of Fish: An Overview of Significant Pathogens  

PubMed Central

The growing global demand for seafood together with the limited capacity of the wild-capture sector to meet this demand has seen the aquaculture industry continue to grow around the world. A vast array of aquatic animal species is farmed in high density in freshwater, brackish and marine systems where they are exposed to new environments and potentially new diseases. On-farm stresses may compromise their ability to combat infection, and farming practices facilitate rapid transmission of disease. Viral pathogens, whether they have been established for decades or whether they are newly emerging as disease threats, are particularly challenging since there are few, if any, efficacious treatments, and the development of effective viral vaccines for delivery in aquatic systems remains elusive. Here, we review a few of the more significant viral pathogens of finfish, including aquabirnaviruses and infectious hematopoietic necrosis virus which have been known since the first half of the 20th century, and more recent viral pathogens, for example betanodaviruses, that have emerged as aquaculture has undergone a dramatic expansion in the past few decades.

Crane, Mark; Hyatt, Alex

2011-01-01

245

Master sensors of pathogenic RNA - RIG-I like receptors.  

PubMed

Initiating the immune response to invading pathogens, the innate immune system is constituted of immune receptors (pattern recognition receptors, PRR) that sense microbe-associated molecular patterns (MAMPs). Detection of pathogens triggers intracellular defense mechanisms, such as the secretion of cytokines or chemokines to alarm neighboring cells and attract or activate immune cells. The innate immune response to viruses is mostly based on PRRs that detect the unusual structure, modification or location of viral nucleic acids. Most of the highly pathogenic and emerging viruses are RNA genome-based viruses, which can give rise to zoonotic and epidemic diseases or cause viral hemorrhagic fever. As viral RNA is located in the same compartment as host RNA, PRRs in the cytosol have to discriminate between viral and endogenous RNA by virtue of their structure or modification. This challenging task is taken on by the homologous cytosolic DExD/H-box family helicases RIG-I and MDA5, which control the innate immune response to most RNA viruses. This review focuses on the molecular basis for RIG-I like receptor (RLR) activation by synthetic and natural ligands and will discuss controversial ligand definitions. PMID:23896194

Schlee, Martin

2013-07-01

246

Biosensors for the detection of waterborne pathogens.  

PubMed

Waterborne bacterial, viral and parasitic pathogens are a global health concern and their rapid and specific detection in contaminated potable water is of utmost importance. Biosensors using a variety of biorecognition molecules and transduction methodologies have been reported, and have the potential to enable highly sensitive detection of the analyte of interest in a short time with high specificity. However, there are several obstacles to the detection of waterborne pathogens-they tend to be present at very low concentrations in the environment and environmental samples contain numerous inhibitors of enzymatic reactions and interfering organisms and particulates. Here we present a review of the current state of biosensor technology with regard to the improvements needed over standard detection methods and the challenges presented by real environmental samples. Further, we identify future areas of focus necessary to realize novel detection devices capable of supplanting the gold standards of today. PMID:21956262

Connelly, John T; Baeumner, Antje J

2011-09-29

247

dsRNA sensing during viral infection: lessons from plants, worms, insects, and mammals.  

PubMed

Host defense systems often rely on direct and indirect pattern recognition to sense the presence of invading pathogens. Patterns can be molecules directly produced by the pathogen or indirectly generated by changes in host parameters as a consequence of infection. Viruses are intracellular pathogens that hijack the cellular machinery to synthesize their own molecules making direct recognition of viral molecules a great challenge. Antiviral systems in prokaryotes and eukaryotes commonly exploit aberrant nucleic acid sensing to recognize virus infection as host and viral nucleic acid metabolism can greatly differ. Indeed, the generation of dsRNA is often associated with viral infection. In this review, we discuss current knowledge on the mechanisms of viral dsRNA sensing utilized by 2 important antiviral defense systems, RNA interference (RNAi) and the vertebrate immune system. The major viral sensors of the vertebrate immune systems are RIG-like receptors, while RNAi pathways depend on Dicer proteins. These 2 families of sensors share a similar helicase domain with high specificity for dsRNA, which is necessary, but not sufficient for efficient recognition by these receptors. Additional intrinsic features to the dsRNA molecule are also necessary for activation of antiviral systems. Studies utilizing synthetic ligands, in vitro biochemistry and reporter systems have greatly helped increase our knowledge on intrinsic features of dsRNA recognition. However, characteristics such as subcellular localization are extrinsic to the dsRNA itself, but certainly influence the recognition in vivo. Thus, mechanisms of viral dsRNA recognition must address how cellular sensors are recruited to nucleic acids or vice versa. Accessory proteins are likely important for in vivo recognition of extrinsic features of viral RNA, but have mostly remained undiscovered due to the limitations of previous strategies. Hence, the identification of novel components of antiviral systems must take into account the complexities involved in viral recognition in vivo. PMID:23656598

de Faria, Isaque João da Silva; Olmo, Roenick Proveti; Silva, Emanuele Guimarães; Marques, João Trindade

2013-05-01

248

Viral hepatitis and the surgeon  

PubMed Central

Background. Viral hepatitis is an infection of the liver caused by one or more of six known (HAV-HGV) hepatotropic viruses. It is a common problem among health care workers and their patients. Surgeons are at particular risk of both acquiring and transmitting some of these viruses from and to their patients. Unfortunately, specific immunoprophylaxis for viral hepatitis is presently limited to protecting against the spread of hepatitis A and B viral infections, leaving a high degree of vigilance and careful surgical technique as the only means available to prevent the transmission of other viruses relative to the surgeon. The purpose of this paper is to review the various forms of viral hepatitis including the nature of the virus, serologic testing, clinical features, epidemiology (with specific reference to those issues that arise in surgical practice), treatment and prevention.

Cohen, A. J.; Assy, N.; Moser, M.

2005-01-01

249

[Viral infection and ear diseases].  

PubMed

The association of viral infection to ear disease has triggered a great deal of interests. In the present paper, we provide a critical review of the viral hypothesis of ear diseases. Detection of viral antigen and antibody or RNA and DNA in the patients serum, endolymphatic fluid or surgical pathology specimens reveals that virus may have relevance to certain kinds of ear diseases, such as Meniere's disease, idiopathic sudden sensorineural hearing loss, otosclerosis. Bell's palsy and otitis media. The most appealing is the herpesvirus, which can cause latent infection in the neurons, and its reactivation may be the mechanism of recurrent attacks of ear diseases. Currently, antiviral drug treatment plus supportive therapy are the most effective managements dealing with viral infection. Although antiviral vaccine will become a promising preventive strategy in the future. PMID:23937021

Liu, Yuehang; Wang, Zhengmin

2013-05-01

250

High Consequence Plant Pathogens  

Microsoft Academic Search

Threatening pathogens present a great concern since they can impact agriculture, economy, international trade and environmental\\u000a diversity. Among the pathogens which cause increased agricultural and social concern are new or re-emerging pathogens. Most\\u000a of the important agricultural crops have spread during the last two centuries outside their original environment all over\\u000a the world. An immediate and parallel trend is the

Abraham Gamliel

251

Pathogenic Microorganisms in Water  

NSDL National Science Digital Library

Pathogenic Microorganisms in Water: Traditionally, groundwater has been used without treatment because the soil acts as a filter, removing pathogenic microorganisms. Some potential sources of pathogens (or disease causing organisms) in groundwater include septic tanks, leaking sewer lines, sewage sludge, intentional groundwater recharge with sewage, irrigation with sewage, direct injection of sewage, domestic solid waste disposal (landfills) and sewage oxidation ponds. The objective of the session is to introduce hydrogeologist to the types of microorganisms, sources of pathogens, and a simple exercise that can be incorporated into a hydrogeology class.

Lenczewski, Melissa

252

Pathogenicity of Chinese H5N1 highly pathogenic avian influenza viruses in pigeons.  

PubMed

It has long been thought that pigeons are resistant against H5 highly pathogenic avian influenza (HPAI) viruses. Recently, however, highly pathogenic H5N1 avian influenza viruses have demonstrated distinct biological properties that may be capable of causing disease in pigeons. To examine the susceptibility of domestic pigeons to recent H5N1 viruses, we inoculated pigeons using H5N1 viruses isolated in China from 2002 to 2004. Within 21 days following inoculation, all pigeons had survived and fully recovered from temporary clinical signs. However, seroconversion assays demonstrated that several viruses did in fact establish infection in pigeons and caused a certain amount of viral shedding in the oropharynx and cloaca. There was not, however, a definitive relationship between viral shedding and viral origin. Viruses were also inconsistently isolated from various organs of pigeons in infected groups. Pathological examination revealed that the infection had started as respiratory inflammation and caused the most severe lesions in the brain in later stages. These results indicate that pigeons are susceptible to the more recent Asian H5N1 HPAI and could be a source of infection to other animals, including humans. PMID:18779923

Jia, Beibei; Shi, Jianzhong; Li, Yanbing; Shinya, Kyoko; Muramoto, Yukiko; Zeng, Xianying; Tian, Guobin; Kawaoka, Yoshihiro; Chen, Hualan

2008-09-09

253

Direct exposure to animal enteric pathogens.  

PubMed

Humans have very close interactions with working, food-producing, and companion animals. According to the American Veterinary Medical Association, there are more than one hundred million cat and dog pets in the United States. Furthermore, non-traditional pets like reptiles and exotic birds are not unusual companion animals in households. In addition to sharing with animals our living and/or working space and time, we also share, unfortunately, many disease causing microorganisms. In the past few years, we have become aware that several enteric pathogens that were thought to be mostly restricted to animals are a major cause of human disease. Examples of such pathogens include the protozoan parasite Cryptosporidium parvum and bacteria such as Campylobacter spp. This review will examine the characteristics of zoonotic enteric pathogens including bacterial (Helicobacter spp., Campylobacter spp., Salmonella spp., and verotoxin-producing Escherichia coli); parasitic (Toxoplasma gondii, Giardia spp., Cryptosporidium spp.); and viral (rotavirus, norwalk-like virus, hepatitis E virus), and the status of our knowledge with regard to the impact of such pathogens on human health. PMID:11512628

Enriquez, C; Nwachuku, N; Gerba, C P

254

The hepatitis C virus Core protein is a potent nucleic acid chaperone that directs dimerization of the viral (+) strand RNA in vitro  

Microsoft Academic Search

The hepatitis C virus (HCV) is an important human pathogen causing chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. HCV is an enveloped virus with a positive-sense, single-stranded RNA genome encoding a single polyprotein that is processed to generate viral proteins. Several hundred molecules of the structural Core protein are thought to coat the genome in the viral particle, as do

Gael Cristofari; Roland Ivanyi-Nagy; Caroline Gabus; Steeve Boulant; Jean-Pierre Lavergne; Francois Penin; Jean-Luc Darlix

2004-01-01

255

Recent advances in targeting viral proteases for the discovery of novel antivirals.  

PubMed

The occurrence of life-threatening viral infections and the establishment of appropriate defense strategies exhibit major challenges to the disease management in our society. The unpredictable character of viral outbreaks will even be enhanced in the future due to human activities such as increasing international travel, deforestation, changes in social conditions, or influences induced by the climate change. The defense against these pathogenic agents requires preparedness, including successful drug design strategies. Viral proteases represent attractive targets for the design of anti-infective lead compounds, as in case that a viral mRNA encoding several types of proteins is recognized as a monocistronic template by the host-cell translation machinery, the presence of protease activities is required for processing the viral polyprotein precursor into structural or non-structural components essential for the formation of new virion particles. In addition, viral proteases can be involved in further processes relevant for viral replication. Numerous efforts have been made to develop potent small-molecule inhibitors of viral proteases, however, until now only a limited number reached the market. In the present contribution, functional aspects of the target proteases, their structural properties, drug design strategies, resulting inhibitors, and resistance management are reviewed and discussed by means of the four essential representative cases of HIV, HCV, SARS coronavirus, and the flaviviruses Dengue and West Nile virus. PMID:20166951

Steuber, Holger; Hilgenfeld, Rolf

2010-01-01

256

Detection of Inhibition of Bovine Viral Diarrhea Virus by Aromatic Cationic Molecules  

Microsoft Academic Search

Received 8 October 2002\\/Returned for modification 12 December 2002\\/Accepted 24 March 2003 Bovine viral diarrhea virus (BVDV) is an economically significant pathogen of cattle and a problematic contaminant in the laboratory. BVDV is often used as an in vitro model for hepatitis C virus during drug discovery efforts. Aromatic dicationic molecules have exhibited inhibitory activity against several RNA viruses. Thus,

M. Daniel Givens; Christine C. Dykstra; Kenny V. Brock; David A. Stringfellow; Arvind Kumar; Chad E. Stephens; Hakan Goker; David W. Boykin

2003-01-01

257

Noncytopathic Bovine Viral Diarrhea Virus Inhibits Double-Stranded RNA-Induced Apoptosis and Interferon Synthesis  

Microsoft Academic Search

Bovine viral diarrhea virus (BVDV), a pestivirus of the Flaviviridae family, is an economically important cattle pathogen with a worldwide distribution. Both noncytopathic (ncp) and cytopathic (cp) biotypes of BVDV can be isolated from persistently infected cattle suffering from the lethal mucosal disease. The cp biotype correlates with the production of the NS3 nonstructural protein, which in the corresponding ncp

MATTHIAS SCHWEIZER; ERNST PETERHANS

2001-01-01

258

Bovine viral diarrhea virus infection alters global transcription profiles in bovine endothelial cells  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bovine viral diarrhea viruses (BVDV) are significant pathogens of cattle worldwide. These viruses exist in both non-cytopathic and cytopathic biotypes. Non-cytopathic BVDV can establish persistent lifelong infections in cattle and are a frequent contaminant of biological reagents such as cell cultur...

259

The Structure of Marek Disease Virus DNA: The Presence of Unique Expansion in Nonpathogenic Viral DNA  

Microsoft Academic Search

DNA of Marek disease virus (MDV) consists of two unique regions UL and US flanked by long inverted repeat regions TRL and IRL, and short inverted repeat regions TRS and IRS, respectively, similar to herpes simplex virus DNA. Comparison of restriction patterns between pathogenic and nonpathogenic MDV DNA was made to identify a region of viral DNA different between these

K. Fukuchi; A. Tanaka; L. W. Schierman; R. L. Witter; M. Nonoyama

1985-01-01

260

Antigen quantification as in vitro alternative for potency testing of inactivated viral poultry vaccines  

Microsoft Academic Search

Routine batch control of licensed inactivated viral vaccines for poultry usually includes a potency assay as a measure of vaccine efficacy. Potency assays often consist of vaccination?challenge experiments in the target species or in laboratory animals. Instead of measuring the protection of vaccinated animals against virulent pathogens, the serological response after vaccination can be quantified for some vaccines. In vitro

P. A. Maas; M. P. M. de Winter; S. Venema; H. L. Oei; I. J. T. M. Claassen

2000-01-01

261

Production of a highly immunogenic subunit ISCOM vaccine against Bovine Viral Diarrhea Virus  

Microsoft Academic Search

Bovine Viral Diarrhea Virus (BVDV) is a major pathogen of cattle in most countries. The main reservoir of virus in herds are BVDV persistently infected animals, which arise as a result of infection of the bovine fetus early in gestation. The spread of virus to the unborn fetus may be prevented by vaccination of the dam. We describe in this

S. Kamstrup; L. Roensholt; M. Holm Jensen; K. Dalsgaard

1999-01-01

262

Comparison of Coliforms and Coliphages as Tools for Assessment of Viral Contamination in River Water  

Microsoft Academic Search

The aim of the study was to evaluate the presence of pathogenic viruses in the Moselle River and to compare the usefulness of thermotolerant coliforms and somatic coliphages as tools for river water quality assessment in terms of viral contamination. Thermotolerant coliforms and somatic coliphages were enumerated by standardized methods in 170 samples of river water drawn from five sampling

S. Skraber; B. Gassilloud; C. Gantzer

2004-01-01

263

CD46 Is a Cellular Receptor for Bovine Viral Diarrhea Virus  

Microsoft Academic Search

Bovine viral diarrhea virus (BVDV) is a small enveloped RNA virus which belongs to the genus Pestivirus within the family Flaviviridae. Pestiviruses are widespread among cloven- hoofed animals (Artiodactyla), causing disease in ruminants (Bos, Ovis, and Camelidae) and nonruminants (Suidae). BVDV is an important pathogen of cattle and accounts for syndromes of the intestinal, respiratory, and reproductive tracts. While the

Karin Maurer; Thomas Krey; Volker Moennig; Heinz-Jurgen Thiel; Till Rumenapf

2004-01-01

264

Characterization of Nonpathogenic, Live, Viral Vaccine Vectors Inducing Potent Cellular Immune Responses  

Microsoft Academic Search

Experimental vaccines based on recombinant vesicular stomatitis viruses (VSV) expressing foreign viral proteins are protective in several animal disease models. Although these attenuated viruses are nonpathogenic in nonhuman primates when given by nasal, oral, or intramuscular routes, they are pathogenic in mice when given intranasally, and further vector attenuation may be required before human trials with VSV-based vectors can begin.

Jean Publicover; Elizabeth Ramsburg; John K. Rose

2004-01-01

265

Acute and Chronic Airway Responses to Viral Infection: Implications for Asthma and Chronic Obstructive Pulmonary Disease  

Microsoft Academic Search

Despite the high clinical impact of established and emerging respi- ratory viruses, some critical aspects of the host response to these pathogens still need to be defined. In that context, we aimed at two major issues: first, what are the innate immune mechanisms that control common respiratory viral infections; and second, whether these mechanisms also cause long-term airway disease. Using

Michael J. Holtzman; Jeffrey W. Tyner; Edy Y. Kim; Mindy S. Lo; Anand C. Patel; Laurie P. Shornick; Eugene Agapov; Yong Zhang

2005-01-01

266

Molecular piracy: the viral link to carcinogenesis  

Microsoft Academic Search

The vast majority of the human experience with viral infectons is associated with acute symptoms, such as malaise, fever, chills, rhinitis and diarrhea. With this acute or lytic phase, the immune system mounts a response and eliminates the viral agent while acquiring antibodies to that specific viral subtype. With latent or chronic infections, the viral agent becomes incorporated into the

C. M. Flaitz; M. J. Hicks

1998-01-01

267

Enteric pathogens associated with childhood diarrhea in Tripoli-Libya.  

PubMed

Stool samples from children < 5 years of age with diarrhea (N = 239) were examined for enteric pathogens using a combination of culture, enzyme-immunoassay, and polymerase chain reaction methods. Pathogens were detected in 122 (51%) stool samples; single pathogens were detected in 37.2% and co-pathogens in 13.8% of samples. Norovirus, rotavirus, and diarrheagenic Escherichia coli (DEC) were the most frequently detected pathogens (15.5%, 13.4%, and 11.2%, respectively); Salmonella, adenovirus, and Aeromonas were detected less frequently (7.9%, 7.1%, and 4.2%). The most commonly detected DEC was enteroaggregative E. coli (5.4%). Resistance to ? 3 antimicrobials was observed in 60% (18/30) of the bacterial pathogens. Salmonella resistance to ciprofloxacin (63.1%) has become a concern. Enteric viral pathogens were the most significant causative agents of childhood diarrhea in Tripoli. Bacterial pathogens were also important contributors to pediatric diarrhea. The emergence of ciprofloxacin-resistant Salmonella represents a serious health problem that must be addressed by Libyan health authorities. PMID:21633024

Rahouma, Amal; Klena, John D; Krema, Zaineb; Abobker, Abdalwahed A; Treesh, Khalid; Franka, Ezzedin; Abusnena, Omar; Shaheen, Hind I; El Mohammady, Hanan; Abudher, Abdulhafid; Ghenghesh, Khalifa Sifaw

2011-06-01

268

Enteric Pathogens Associated with Childhood Diarrhea in Tripoli-Libya  

PubMed Central

Stool samples from children < 5 years of age with diarrhea (N = 239) were examined for enteric pathogens using a combination of culture, enzyme-immunoassay, and polymerase chain reaction methods. Pathogens were detected in 122 (51%) stool samples; single pathogens were detected in 37.2% and co-pathogens in 13.8% of samples. Norovirus, rotavirus, and diarrheagenic Escherichia coli (DEC) were the most frequently detected pathogens (15.5%, 13.4%, and 11.2%, respectively); Salmonella, adenovirus, and Aeromonas were detected less frequently (7.9%, 7.1%, and 4.2%). The most commonly detected DEC was enteroaggregative E. coli (5.4%). Resistance to ? 3 antimicrobials was observed in 60% (18/30) of the bacterial pathogens. Salmonella resistance to ciprofloxacin (63.1%) has become a concern. Enteric viral pathogens were the most significant causative agents of childhood diarrhea in Tripoli. Bacterial pathogens were also important contributors to pediatric diarrhea. The emergence of ciprofloxacin-resistant Salmonella represents a serious health problem that must be addressed by Libyan health authorities

Rahouma, Amal; Klena, John D.; Krema, Zaineb; Abobker, Abdalwahed A.; Treesh, Khalid; Franka, Ezzedin; Abusnena, Omar; Shaheen, Hind I.; El Mohammady, Hanan; Abudher, Abdulhafid; Ghenghesh, Khalifa Sifaw

2011-01-01

269

Tropical dermatology: viral tropical diseases  

Microsoft Academic Search

Viruses are important pathogens in tropical areas; most of them, especially the tropical hemorrhagic fevers, produce mucocutaneous manifestations. More than any other kind of pathogen, viruses have the possibility for being widespread, since they have a greater probability of mutation than do bacteria, can cross species barriers easily, and infect both human beings and animals in habitats with a great

Omar Lupi; Stephen K. Tyring

2003-01-01

270

Parvovirus B19 DNA CpG Dinucleotide Methylation and Epigenetic Regulation of Viral Expression  

PubMed Central

CpG DNA methylation is one of the main epigenetic modifications playing a role in the control of gene expression. For DNA viruses whose genome has the ability to integrate in the host genome or to maintain as a latent episome, a correlation has been found between the extent of DNA methylation and viral quiescence. No information is available for Parvovirus B19, a human pathogenic virus, which is capable of both lytic and persistent infections. Within Parvovirus B19 genome, the inverted terminal regions display all the characteristic signatures of a genomic CpG island; therefore we hypothesised a role of CpG dinucleotide methylation in the regulation of viral genome expression. The analysis of CpG dinucleotide methylation of Parvovirus B19 DNA was carried out by an aptly designed quantitative real-time PCR assay on bisulfite-modified DNA. The effects of CpG methylation on the regulation of viral genome expression were first investigated by transfection of either unmethylated or in vitro methylated viral DNA in a model cell line, showing that methylation of viral DNA was correlated to lower expression levels of the viral genome. Then, in the course of in vitro infections in different cellular environments, it was observed that absence of viral expression and genome replication were both correlated to increasing levels of CpG methylation of viral DNA. Finally, the presence of CpG methylation was documented in viral DNA present in bioptic samples, indicating the occurrence and a possible role of this epigenetic modification in the course of natural infections. The presence of an epigenetic level of regulation of viral genome expression, possibly correlated to the silencing of the viral genome and contributing to the maintenance of the virus in tissues, can be relevant to the balance and outcome of the different types of infection associated to Parvovirus B19.

Bonvicini, Francesca; Manaresi, Elisabetta; Di Furio, Francesca; De Falco, Luisa; Gallinella, Giorgio

2012-01-01

271

Development of an aquatic pathogen database (AquaPathogen X) and its utilization in tracking emerging fish virus pathogens in North America.  

PubMed

The AquaPathogen X database is a template for recording information on individual isolates of aquatic pathogens and is freely available for download (http://wfrc.usgs.gov). This database can accommodate the nucleotide sequence data generated in molecular epidemiological studies along with the myriad of abiotic and biotic traits associated with isolates of various pathogens (e.g. viruses, parasites and bacteria) from multiple aquatic animal host species (e.g. fish, shellfish and shrimp). The cataloguing of isolates from different aquatic pathogens simultaneously is a unique feature to the AquaPathogen X database, which can be used in surveillance of emerging aquatic animal diseases and elucidation of key risk factors associated with pathogen incursions into new water systems. An application of the template database that stores the epidemiological profiles of fish virus isolates, called Fish ViroTrak, was also developed. Exported records for two aquatic rhabdovirus species emerging in North America were used in the implementation of two separate web-accessible databases: the Molecular Epidemiology of Aquatic Pathogens infectious haematopoietic necrosis virus (MEAP-IHNV) database (http://gis.nacse.org/ihnv/) released in 2006 and the MEAP- viral haemorrhagic septicaemia virus (http://gis.nacse.org/vhsv/) database released in 2010. PMID:21762169

Emmenegger, E J; Kentop, E; Thompson, T M; Pittam, S; Ryan, A; Keon, D; Carlino, J A; Ranson, J; Life, R B; Troyer, R M; Garver, K A; Kurath, G

2011-08-01

272

Microsporidia: emerging pathogenic protists  

Microsoft Academic Search

Microsporidia are eukaryotic spore forming obligate intracellular protozoan parasites first recognized over 100 years ago. These organisms infect all of the major animal groups and are now recognized as opportunistic pathogens of humans. Microsporidian spores are common in the environment and microsporidia pathogenic to humans have been found in water supplies. The genera Nosema, Vittaforma, Brachiola, Pleistophora, Encephalitozoon, Enterocytozoon, Septata

Louis M. Weiss

2001-01-01

273

Emerging Escherichia pathogen.  

PubMed

Escherichia hermannii was first identified as a new species in 1982. It has rarely been reported as a human pathogen. We report the first case of E. hermannii as the sole pathogen in a catheter-related bloodstream infection. PMID:23740732

Kaewpoowat, Quanhathai; Permpalung, Nitipong; Sentochnik, Deborah E

2013-06-05

274

Plant pathogen resistance  

SciTech Connect

Azelaic acid or its derivatives or analogs induce a robust and a speedier defense response against pathogens in plants. Azelaic acid treatment alone does not induce many of the known defense-related genes but activates a plant's defense signaling upon pathogen exposure.

Greenberg, Jean T; Jung, Ho Won; Tschaplinski, Timothy

2012-11-27

275

Pathogens: raft hijackers  

Microsoft Academic Search

Throughout evolution, organisms have developed immune-surveillance networks to protect themselves from potential pathogens. At the cellular level, the signalling events that regulate these defensive responses take place in membrane rafts — dynamic microdomains that are enriched in cholesterol and glycosphingolipids — that facilitate many protein–protein and lipid–protein interactions at the cell surface. Pathogens have evolved many strategies to ensure their

Santos Mañes; Gustavo del Real; Carlos Martínez-A

2003-01-01

276

Plant pathogenic Pseudomonas species  

Microsoft Academic Search

In the current taxonomy, plant pathogenic Pseudomonas species are restricted to rRNA group I organisms belonging to the Gamma subclass of Proteobacteria. Currently, about 21 validly described plant pathogenic Pseudomonas species are known. The most important species is P. syringae with more than 50 described pathovars. The pathovar concept is confusing and the taxonomy of P. syringae needs revision. P.

Monica Höfte; PAUL DE VOS

277

[From acute viral bronchiolitis in infancy to asthma in childhood].  

PubMed

Bronchiolitis and wheezy bronchitis are frequently associated with viral infection of the respiratory tract in infants. They play an important role in the natural history of chronic obstructive airway disease, not only in children, but also in adults. The risk of early recurrent wheezing and subsequent asthma or chronic bronchitis (with anatomical sequelae such as obliterans bronchiolitis) is significant. The precise pathogenic mechanisms of virus-induced wheezing and its sequelae are not clear. Whether airway hyperreactivity is inherited and airway hyperreactivity is present prior to, or is the result of bronchiolitis is not clear. Nevertheless the evidence for viral trigger of wheezing and long-term pulmonary sequelae must be considered and prevention must be undertaken at the first episode. PMID:1329009

Bellon, G

1992-01-01

278

Viral Infection: An Evolving Insight into the Signal Transduction Pathways Responsible for the Innate Immune Response  

PubMed Central

The innate immune response is initiated by the interaction of stereotypical pathogen components with genetically conserved receptors for extracytosolic pathogen-associated molecular patterns (PAMPs) or intracytosolic nucleic acids. In multicellular organisms, this interaction typically clusters signal transduction molecules and leads to their activations, thereby initiating signals that activate innate immune effector mechanisms to protect the host. In some cases programmed cell death—a fundamental form of innate immunity—is initiated in response to genotoxic or biochemical stress that is associated with viral infection. In this paper we will summarize innate immune mechanisms that are relevant to viral pathogenesis and outline the continuing evolution of viral mechanisms that suppress the innate immunity in mammalian hosts. These mechanisms of viral innate immune evasion provide significant insight into the pathways of the antiviral innate immune response of many organisms. Examples of relevant mammalian innate immune defenses host defenses include signaling to interferon and cytokine response pathways as well as signaling to the inflammasome. Understanding which viral innate immune evasion mechanisms are linked to pathogenesis may translate into therapies and vaccines that are truly effective in eliminating the morbidity and mortality associated with viral infections in individuals.

Kotwal, Girish J.; Hatch, Steven; Marshall, William L.

2012-01-01

279

Viral inactivation based on inhibition of membrane fusion: understanding the role of histidine protonation to develop new viral vaccines.  

PubMed

Membrane fusion is an essential step in the entry of enveloped viruses into their host cells, what makes it a potentially attractive target for viral inactivation approaches. Fusion is mediated by viral surface glycoproteins that undergo conformational changes triggered by interaction with specific cellular receptors or by the exposition to low pH of endossomal medium. Here we review how several studies on the structural rearrangements of vesicular stomatitis virus (VSV) glycoprotein G during cellular recognition and fusion led us to propose a crucial role of the protonation of His residues for G protein activity. Moreover, we demonstrated that using diethylpyrocarbonate (DEPC), a histidine-modifying compound, it was possible to abolish viral infectivity and pathogenicity in mice, and to elicit neutralizing antibodies that confer protection in these animals against challenge using lethal doses of the virus. The presence of conserved His residues in a wide range of viral fusion proteins and the use of DEPC as a more general means for vaccine development will be also discussed. PMID:19601907

Da Poian, A T; Carneiro, F A; Stauffer, F

2009-01-01

280

GeMInA, Genomic Metadata for Infectious Agents, a geospatial surveillance pathogen database  

PubMed Central

The Gemina system (http://gemina.igs.umaryland.edu) identifies, standardizes and integrates the outbreak metadata for the breadth of NIAID category A–C viral and bacterial pathogens, thereby providing an investigative and surveillance tool describing the Who [Host], What [Disease, Symptom], When [Date], Where [Location] and How [Pathogen, Environmental Source, Reservoir, Transmission Method] for each pathogen. The Gemina database will provide a greater understanding of the interactions of viral and bacterial pathogens with their hosts and infectious diseases through in-depth literature text-mining, integrated outbreak metadata, outbreak surveillance tools, extensive ontology development, metadata curation and representative genomic sequence identification and standards development. The Gemina web interface provides metadata selection and retrieval of a pathogen's; Infection Systems (Pathogen, Host, Disease, Transmission Method and Anatomy) and Incidents (Location and Date) along with a hosts Age and Gender. The Gemina system provides an integrated investigative and geospatial surveillance system connecting pathogens, pathogen products and disease anchored on the taxonomic ID of the pathogen and host to identify the breadth of hosts and diseases known for these pathogens, to identify the extent of outbreak locations, and to identify unique genomic regions with the DNA Signature Insignia Detection Tool.

Schriml, Lynn M.; Arze, Cesar; Nadendla, Suvarna; Ganapathy, Anu; Felix, Victor; Mahurkar, Anup; Phillippy, Katherine; Gussman, Aaron; Angiuoli, Sam; Ghedin, Elodie; White, Owen; Hall, Neil

2010-01-01

281

GeMInA, Genomic Metadata for Infectious Agents, a geospatial surveillance pathogen database.  

PubMed

The Gemina system (http://gemina.igs.umaryland.edu) identifies, standardizes and integrates the outbreak metadata for the breadth of NIAID category A-C viral and bacterial pathogens, thereby providing an investigative and surveillance tool describing the Who [Host], What [Disease, Symptom], When [Date], Where [Location] and How [Pathogen, Environmental Source, Reservoir, Transmission Method] for each pathogen. The Gemina database will provide a greater understanding of the interactions of viral and bacterial pathogens with their hosts and infectious diseases through in-depth literature text-mining, integrated outbreak metadata, outbreak surveillance tools, extensive ontology development, metadata curation and representative genomic sequence identification and standards development. The Gemina web interface provides metadata selection and retrieval of a pathogen's; Infection Systems (Pathogen, Host, Disease, Transmission Method and Anatomy) and Incidents (Location and Date) along with a hosts Age and Gender. The Gemina system provides an integrated investigative and geospatial surveillance system connecting pathogens, pathogen products and disease anchored on the taxonomic ID of the pathogen and host to identify the breadth of hosts and diseases known for these pathogens, to identify the extent of outbreak locations, and to identify unique genomic regions with the DNA Signature Insignia Detection Tool. PMID:19850722

Schriml, Lynn M; Arze, Cesar; Nadendla, Suvarna; Ganapathy, Anu; Felix, Victor; Mahurkar, Anup; Phillippy, Katherine; Gussman, Aaron; Angiuoli, Sam; Ghedin, Elodie; White, Owen; Hall, Neil

2009-10-22

282

Epidemiology of the spread of viral diseases under aquaculture.  

PubMed

Aquaculture production is increasing rapidly worldwide. However, production has been associated with the emergence of several novel diseases, including viral diseases, that have caused serious problems for producers. Using examples largely from salmon farming in Scotland I review briefly the factors that allow transmission to occur in aquaculture. These include transmission through the water, which is relatively local to the infected farm, and anthropogenic transports (such as transport of fish between sites) that may occur over very long distances. A Disease Management Area (DMA) approach, as developed in Scotland to fight infectious salmon anaemia, can be effective at reducing pathogen transmission and hence disease emergence. PMID:23206337

Murray, Alexander G

2012-12-01

283

Other viral pneumonias: coronavirus, respiratory syncytial virus, adenovirus, hantavirus.  

PubMed

Severe viral pneumonia is an increasing problem among adults. The incidence and number of viruses known to cause pneumonia and respiratory failure have also expanded in recent years. This article provides an overview of severe respiratory disease caused by coronavirus, respiratory syncytial virus, adenovirus, and hantavirus. These emerging pathogens are easily overlooked and timely diagnosis requires a high index of suspicion and confirmation by molecular testing. Management of individual cases is mainly supportive and requires institution of appropriate infection control measures. Vaccines and effective therapeutics for these potentially devastating respiratory viruses are urgently required. PMID:24094390

Lee, Nelson; Qureshi, Salman T

2013-08-09

284

Systems Integration of Biodefense Omics Data for Analysis of Pathogen-Host Interactions and Identification of Potential Targets  

Microsoft Academic Search

The NIAID (National Institute for Allergy and Infectious Diseases) Biodefense Proteomics program aims to identify targets for potential vaccines, therapeutics, and diagnostics for agents of concern in bioterrorism, including bacterial, parasitic, and viral pathogens. The program includes seven Proteomics Research Centers, generating diverse types of pathogen-host data, including mass spectrometry, microarray transcriptional profiles, protein interactions, protein structures and biological reagents.

Peter B. McGarvey; Hongzhan Huang; Raja Mazumder; Jian Zhang; Yongxing Chen; Chengdong Zhang; Stephen Cammer; Rebecca Will; Margie Odle; Bruno Sobral; Margaret Moore; Cathy H. Wu; Jörg Hoheisel

2009-01-01

285

Noncoding RNPs of Viral Origin  

PubMed Central

SUMMARY Like their host cells, many viruses produce noncoding (nc)RNAs. These show diversity with respect to time of expression during viral infection, length and structure, protein-binding partners and relative abundance compared with their host-cell counterparts. Viruses, with their limited genomic capacity, presumably evolve or acquire ncRNAs only if they selectively enhance the viral life cycle or assist the virus in combating the host’s response to infection. Despite much effort, identifying the functions of viral ncRNAs has been extremely challenging. Recent technical advances and enhanced understanding of host-cell ncRNAs promise accelerated insights into the RNA warfare mounted by this fascinating class of RNPs.

Steitz, Joan; Borah, Sumit; Cazalla, Demian; Fok, Victor; Lytle, Robin; Mitton-Fry, Rachel; Riley, Kasandra; Samji, Tasleem

2011-01-01

286

Signaling During Pathogen Infection  

NSDL National Science Digital Library

Pathogens infect almost every living organism. In animals, including humans, the diversity of pathogens ranges from viruses, bacteria, and unicellular parasites to complex fungi, worms, and arthropods. Because pathogens have coevolved with their hosts and have sometimes been coopted as symbionts or commensals, each pathogen/host pair represents a striking success story of survival that reflects the biological complexity of both parties. All invading microorganisms face similar problems, such as gaining access to their host, achieving successful replication, and spreading to a similar or different host. It is therefore not surprising that many different pathogens target similar organs, cell types, and even molecules to achieve their goals. However, no two microbial parasites appear to be completely alike. Although they often target similar signaling networks, they do so in subtly different ways to achieve the desired outcome. This review has eight figures, three movies, and 139 citations and emphasizes two well-established signaling pathways that are often activated during the interaction of different pathogens with their host cells. It illustrates a small part of how the dissection of host/pathogen interactions can reveal, on a molecular scale, a nature shaped by evolutionary forces that can rival the great descriptions of our macroscopic world.

Sylvia Munter (University of Heidelberg Medical School;Department of Parasitology REV); Michael Way (London Research Institute;Cancer Research UK REV); Freddy Frischknecht (University of Heidelberg Medical School;Department of Parasitology REV)

2006-05-16

287

Caspase-12 controls West Nile virus infection via the viral RNA receptor RIG-I  

PubMed Central

Caspase-12 has been shown to negatively modulate inflammasome signaling during bacterial infection. Its function in viral immunity, however, has not been characterized. We now report an important role for caspase-12 in controlling viral infection via the pattern-recognition receptor RIG-I. After challenge with West Nile virus (WNV), caspase-12-deficient mice had greater mortality, higher viral burden and defective type I interferon response compared with those of challenged wild-type mice. In vitro studies of primary neurons and mouse embryonic fibroblasts showed that caspase-12 positively modulated the production of type I interferon by regulating E3 ubiquitin ligase TRIM25–mediated ubiquitination of RIG-I, a critical signaling event for the type I interferon response to WNV and other important viral pathogens.

Wang, Penghua; Arjona, Alvaro; Zhang, Yue; Sultana, Hameeda; Dai, Jianfeng; Yang, Long; LeBlanc, Philippe M; Doiron, Karine; Saleh, Maya; Fikrig, Erol

2013-01-01

288

Structure, function and physiological consequences of virally encoded chemokine seven transmembrane receptors  

PubMed Central

A number of human and animal herpes viruses encode G-protein coupled receptors with seven transmembrane (7TM) segments—most of which are clearly related to human chemokine receptors. It appears, that these receptors are used by the virus for immune evasion, cellular transformation, tissue targeting, and possibly for cell entry. In addition, many virally-encoded chemokine 7TM receptors have been suggested to be causally involved in pathogenic phenotypes like Kaposi sarcoma, atherosclerosis, HIV-infection and tumour development. The role of these receptors during the viral life cycle and in viral pathogenesis is still poorly understood. Here we focus on the current knowledge of structure, function and trafficking patterns of virally encoded chemokine receptors and further address the putative roles of these receptors in virus survival and host -cell and/or -immune system modulation. Finally, we highlight the emerging impact of these receptor on virus-mediated diseases.

Rosenkilde, M M; Smit, M J; Waldhoer, M

2008-01-01

289

[An update on viral diseases of the dog and cat].  

PubMed

In this review, recent developments in the field of viral diseases of the dog and the cat are discussed. In the dog, infection with the coronavirus type 2 is associated with respiratory signs, while infection of a highly pathogenic strain of the coronavirus type 1 has been identified as the cause of mortality in puppies. A new strain of the canine parvovirus is identified, from which the pathogenicity is not yet completely clarified. Infection with West Nile virus is associated with progressive neurological disease and subclinical infections in dogs. Infection with equine influenza A (H3N8) or a highly related influenza virus can cause severe respiratory disease and mortality in greyhounds and other dogs. Infection with avian influenza A (H5N1) can cause disease and mortality in cats and is mostly subclinical in dogs. A number of outbreaks of highly virulent strains of the calicivirus in cats have been described. PMID:19462619

Bodewes, R; Egberink, H F

2009-04-15

290

Human cytomegalovirus latent infection and associated viral gene expression.  

PubMed

Human cytomegalovirus (HCMV) is a clinically important and ubiquitous herpesvirus. Following primary productive infection the virus is not completely eliminated from the host, but instead establishes a lifelong latent infection without detectable virus production, from where it can reactivate at a later stage to generate new infectious virus. Reactivated HCMV often results in life-threatening disease in immunocompromised individuals, particularly allogeneic stem cell and solid organ transplant recipients, where it remains one of the most difficult opportunistic pathogens that complicate the care of these patients. The ability of HCMV to establish and reactivate from latency is central to its success as a human pathogen, yet latency remains very poorly understood. This article will cover several aspects of HCMV latency, with a focus on current understanding of viral gene expression and functions during this phase of infection. PMID:20521934

Slobedman, Barry; Cao, John Z; Avdic, Selmir; Webster, Bradley; McAllery, Samantha; Cheung, Allen Kl; Tan, Joanne Cg; Abendroth, Allison

2010-06-01

291

High Viral Fitness during Acute HIV-1 Infection  

PubMed Central

Several clinical studies have shown that, relative to disease progression, HIV-1 isolates that are less fit are also less pathogenic. The aim of the present study was to investigate the relationship between viral fitness and control of viral load (VL) in acute and early HIV-1 infection. Samples were obtained from subjects participating in two clinical studies. In the PULSE study, antiretroviral therapy (ART) was initiated before, or no later than six months following seroconversion. Subjects then underwent multiple structured treatment interruptions (STIs). The PHAEDRA study enrolled and monitored a cohort of individuals with documented evidence of primary infection. The subset chosen were individuals identified no later than 12 months following seroconversion to HIV-1, who were not receiving ART. The relative fitness of primary isolates obtained from study participants was investigated ex vivo. Viral DNA production was quantified using a novel real time PCR assay. Following intermittent ART, the fitness of isolates obtained from 5 of 6 PULSE subjects decreased over time. In contrast, in the absence of ART the fitness of paired isolates obtained from 7 of 9 PHAEDRA subjects increased over time. However, viral fitness did not correlate with plasma VL. Most unexpected was the high relative fitness of isolates obtained at Baseline from PULSE subjects, before initiating ART. It is widely thought that the fitness of strains present during the acute phase is low relative to strains present during chronic HIV-1 infection, due to the bottleneck imposed upon transmission. The results of this study provide evidence that the relative fitness of strains present during acute HIV-1 infection may be higher than previously thought. Furthermore, that viral fitness may represent an important clinical parameter to be considered when deciding whether to initiate ART during early HIV-1 infection.

Arnott, Alicia; Jardine, Darren; Wilson, Kim; Gorry, Paul R.; Merlin, Kate; Grey, Patricia; Law, Matthew G.; Dax, Elizabeth M.; Kelleher, Anthony D.; Smith, Don E.; McPhee, Dale A.

2010-01-01

292

Nucleic Acid Transport in Plant-Pathogen Interactions  

Microsoft Academic Search

\\u000a Transport of nucleic acid molecules is central to many plant-pathogen interactions. Nucleic acids are transported between\\u000a cells when plant viruses move their genomes from the infected into adjacent uninfected cells through plant intercellular connections,\\u000a the plasmodesmata. DNA and RNA molecules are also transported from the host cell cytoplasm into the nucleus during many viral\\u000a infections. In addition, nuclear import of

Robert Lartey; Vitaly Citovsky

293

Pathogenicity of fowl enteroviruses  

Microsoft Academic Search

The pathogenicity of avian nephritis virus, entero?like particles described by McNulty et al. (Avian Pathology, 13: 429), the entero PV2 and entero 3 isolated in our laboratory, was studied by oral inoculation of one?day?old specific pathogen?free chickens.All viruses were shown by immunofluorescence and transmission electron microscopy to multiply in the cytoplasm of enterocytes but histological lesions of the intestine were

Mireille Decaesstecker; G. Charlier; J. Peeters; G. Meulemans

1989-01-01

294

Small interfering RNAs targeting viral structural envelope protein genes and the 5?-UTR inhibit replication of bovine viral diarrhea virus in MDBK cells.  

PubMed

Bovine viral diarrhea viruses (BVDVs) are important pathogens of cattle that occur worldwide, and for which no antiviral therapy is available. In the present study, the inhibitory effect of small interfering (si) RNAs on bovine viral diarrhea virus 1 (BVDV-1) replication in cultured bovine cells was explored. Four synthetic siRNAs were designed to target structural envelope region genes (Erns, E1, and E2) and one cocktail of siRNA was generated to target the 5?-UTR of the BVDV-1 genome. The inhibitory effects of siRNAs were assessed by determination of infectious viral titer, viral antigen and viral RNA. The siRNA cocktail and three of the synthetic siRNAs produced moderate anti-BVDV-1 effect in vitro as shown by 25%-40% reduction in BVDV-1 antigen production, 7.9-19.9-fold reduction in viral titer and 21-48-fold reduction in BVDV-1 RNA copy number. Our findings suggest that siRNA cocktail targeted at the 5?-UTR is a stronger inhibitor of BVDV-1 replication and the targets for siRNA inhibition can be extended to BVDV-1 structural envelope protein genes. PMID:21978163

Mishra, N; Rajukumar, K; Kalaiyarasu, S; Behera, S P; Nema, R K; Dubey, S C

2011-01-01

295

Post-extraction stabilization of HIV viral RNA for quantitative molecular tests.  

PubMed

Two approaches to stabilize viral nucleic acid in processed clinical specimens were evaluated. HIV-1 RNA extracted from clinical specimens was stabilized in a dry matrix in a commercial product (RNAstable, Biomatrica, San Diego, CA, USA) and in a reverse-transcription reaction mixture in liquid form as cDNA. As few as 145 HIV-1 genome copies of viral RNA are reliably stabilized by RNAstable at 45°C for 92 days and in the cDNA format at 45°C for 7 days as determined by real-time PCR. With RNAstable the R(2) at days 1, 7, and 92 were 0.888, 0.871, and 0.943 when compared to baseline viral load values. The cDNA generated from the same clinical specimens was highly stable with an R(2) value of 0.762 when comparing viral load determinations at day 7 to baseline values. In conclusion viral RNA stabilized in a dry RNAstable matrix is highly stable for long periods of time at high temperatures across a substantial dynamic range. Viral RNA signal can also be stabilized in liquid in the form of cDNA for limited periods of time. Methods that reduce reliance on the cold chain and preserve specimen integrity are critical for extending the reach of molecular testing to low-resource settings. Products based on anhydrobiosis, such as the RNAstable should be evaluated further to support viral pathogen diagnosis. PMID:22433512

Stevens, Daniel S; Crudder, Christopher H; Domingo, Gonzalo J

2012-03-13

296

Bacterial, Fungal, Parasitic, and Viral Myositis  

PubMed Central

Infectious myositis may be caused by a broad range of bacterial, fungal, parasitic, and viral agents. Infectious myositis is overall uncommon given the relative resistance of the musculature to infection. For example, inciting events, including trauma, surgery, or the presence of foreign bodies or devitalized tissue, are often present in cases of bacterial myositis. Bacterial causes are categorized by clinical presentation, anatomic location, and causative organisms into the categories of pyomyositis, psoas abscess, Staphylococcus aureus myositis, group A streptococcal necrotizing myositis, group B streptococcal myositis, clostridial gas gangrene, and nonclostridial myositis. Fungal myositis is rare and usually occurs among immunocompromised hosts. Parasitic myositis is most commonly a result of trichinosis or cystericercosis, but other protozoa or helminths may be involved. A parasitic cause of myositis is suggested by the travel history and presence of eosinophilia. Viruses may cause diffuse muscle involvement with clinical manifestations, such as benign acute myositis (most commonly due to influenza virus), pleurodynia (coxsackievirus B), acute rhabdomyolysis, or an immune-mediated polymyositis. The diagnosis of myositis is suggested by the clinical picture and radiologic imaging, and the etiologic agent is confirmed by microbiologic or serologic testing. Therapy is based on the clinical presentation and the underlying pathogen.

Crum-Cianflone, Nancy F.

2008-01-01

297

Emerging viral diseases of fish and shrimp  

PubMed Central

The rise of aquaculture has been one of the most profound changes in global food production of the past 100 years. Driven by population growth, rising demand for seafood and a levelling of production from capture fisheries, the practice of farming aquatic animals has expanded rapidly to become a major global industry. Aquaculture is now integral to the economies of many countries. It has provided employment and been a major driver of socio-economic development in poor rural and coastal communities, particularly in Asia, and has relieved pressure on the sustainability of the natural harvest from our rivers, lakes and oceans. However, the rapid growth of aquaculture has also been the source of anthropogenic change on a massive scale. Aquatic animals have been displaced from their natural environment, cultured in high density, exposed to environmental stress, provided artificial or unnatural feeds, and a prolific global trade has developed in both live aquatic animals and their products. At the same time, over-exploitation of fisheries and anthropogenic stress on aquatic ecosystems has placed pressure on wild fish populations. Not surprisingly, the consequence has been the emergence and spread of an increasing array of new diseases. This review examines the rise and characteristics of aquaculture, the major viral pathogens of fish and shrimp and their impacts, and the particular characteristics of disease emergence in an aquatic, rather than terrestrial, context. It also considers the potential for future disease emergence in aquatic animals as aquaculture continues to expand and faces the challenges presented by climate change.

Walker, Peter J.; Winton, James R.

2010-01-01

298

Therapeutic treatment for viral infections  

US Patent & Trademark Office Database

The administration internally to humans of 1-(B-hydroxethyl)-2-methyl-5-nitroimidazole, (metronidazole) in a dosage range for adult humans of about 31-2,500 mgs per twenty-four hour period, is an effective therapeutic treatment for certain viral infections causing diverse symptoms, both acute and chronic. Corresponding dosage proportional to body weight appears effective in other mammals also.

Mercer; James B. (Lenexa, KS)

1985-08-27

299

Viral hepatitis in the Arctic  

Microsoft Academic Search

Objectives. Summarize research on viral hepatitis in indigenous populations in the Arctic. Study De- sign. Literature review. Methods. Medline search from 1966-2003. Results. High prevalence rates of total hepatitis A antibody of > 50% and of hepatitis B of between 22% in Alaska and 42% in Greenland for total infection and between 3% in Canada and 12% in Siberia for

Brian J McMahon

300

Viral haemorrhagic fevers of man.  

PubMed

This article reviews the current state of knowledge on the viral haemorrhagic fevers that infect man, namely smallpox, chikungunya fever, dengue fever, Rift Valley fever, yellow fever, Crimean haemorrhagic fever, Kyasanur Forest disease, Omsk haemorrhagic fever, Argentinian haemorrhagic fever (Junin virus), Bolivian haemorrhagic fever (Machupo virus), Lassa fever, haemorrhagic fever with renal syndrome, and Marburg and Ebola virus diseases. PMID:310725

Simpson, D I

1978-01-01

301

Sequencing Needs for Viral Diagnostics  

Microsoft Academic Search

We built a system to guide decisions regarding the amount of genomic sequencing required to develop diagnostic DNA signatures, which are short sequences that are sufficient to uniquely identify a viral species. We used our existing DNA diagnostic signature prediction pipeline, which selects regions of a target species genome that are conserved among strains of the target (for reliability, to

Shea N. Gardner; Marisa W. Lam; Nisha J. Mulakken; Clinton L. Torres; Jason R. Smith; Tom R. Slezak

2004-01-01

302

Viral haemorrhagic fevers of man*  

PubMed Central

This article reviews the current state of knowledge on the viral haemorrhagic fevers that infect man, namely smallpox, chikungunya fever, dengue fever, Rift Valley fever, yellow fever, Crimean haemorrhagic fever, Kyasanur Forest disease, Omsk haemorrhagic fever, Argentinian haemorrhagic fever (Junin virus), Bolivian haemorrhagic fever (Machupo virus), Lassa fever, haemorrhagic fever with renal syndrome, and Marburg and Ebola virus diseases.

Simpson, D. I. H.

1978-01-01

303

Nosocomial Spread of Viral Disease  

PubMed Central

Viruses are important causes of nosocomial infection, but the fact that hospital outbreaks often result from introduction(s) from community-based epidemics, together with the need to initiate specific laboratory testing, means that there are usually insufficient data to allow the monitoring of trends in incidences. The most important defenses against nosocomial transmission of viruses are detailed and continuing education of staff and strict adherence to infection control policies. Protocols must be available to assist in the management of patients with suspected or confirmed viral infection in the health care setting. In this review, we present details on general measures to prevent the spread of viral infection in hospitals and other health care environments. These include principles of accommodation of infected patients and approaches to good hygiene and patient management. They provide detail on individual viral diseases accompanied in each case with specific information on control of the infection and, where appropriate, details of preventive and therapeutic measures. The important areas of nosocomial infection due to blood-borne viruses have been extensively reviewed previously and are summarized here briefly, with citation of selected review articles. Human prion diseases, which present management problems very different from those of viral infection, are not included.

Aitken, Celia; Jeffries, Donald J.

2001-01-01

304

Maternal immunization against viral disease  

Microsoft Academic Search

The protective effect of maternal antibody against many viral diseases has been recognized. The use of maternal immunization has been considered as a means to augment this protection in the young infant against disease. Advantages of maternal immunization include the fact that young infants are most susceptible to infections but least responsive to vaccines, that pregnant women are accessible to

Janet Englund; W. Paul Glezen; Pedro A. Piedra

1998-01-01

305

Dengue viral infections; pathogenesisand epidemiology  

Microsoft Academic Search

Dengue viral infections affect up to 100 million individuals per year. Dengue haemorrhagic fever is a clinical form of disease characterised by intravascular fluid loss. There has been a marked increase in the incidence of this form of the disease over the last few decades, associated with significant mortality, particularly in the paediatric population. A number of theories relating to

William J. H McBride; Helle Bielefeldt-Ohmann

2000-01-01

306

Pathogens involved in lower respiratory tract infections in general practice.  

PubMed Central

BACKGROUND: There are few investigations into the aetiology of lower respiratory tract infections (LRTIs) in general practice. AIM: To describe the aetiology of LRTI among adult patients in general practice in The Netherlands. DESIGN OF STUDY: Prospective observational study. SETTING: General practices in the Leiden region, The Netherlands. METHOD: Adult patients with a defined LRTI were included. Standard medical history and physical examination were performed. Sputum, blood and throat swabs were collected for diagnostic tests. Aetiological diagnosis, categorised as definite or possible, was based on the results of bacterial and viral cultures, serological techniques, and on polymerase chain reaction. Proportions of pathogens causing LRTI were assessed in relation to chest X-ray findings. RESULTS: A bacterial cause was established in 43 (30%), and a viral cause in 57 (39%) of the 145 patients with a LRTI. Influenza virus A was the most frequently diagnosed microorganism, followed by Haemophilus influenzae, and Mycoplasma pneumoniae. Streptococcus pneumoniae was found in 6% of the patients. CONCLUSIONS: Pathogens were found in two-thirds of the patients. In half of these patients there was a viral cause. Influenza virus A was the most frequently found pathogen. The treatment with antibiotics of at least one-third of the patients with LRTI was superfluous. This observation should result in changes in the prescription of antibiotics in LRTI.

Graffelman, A Willy; Knuistingh Neven, Arie; le Cessie, Saskia; Kroes, Aloys C M; Springer, Machiel P; van den Broek, Peterhans J

2004-01-01

307

Herbal medicines for viral myocarditis  

PubMed Central

Background Herbal medicines are being used for treating viral diseases including viral myocarditis, and many controlled trials have been done to investigate their efficacy. Objectives To assess the effects of herbal medicines on clinical and indirect outcomes in patients with viral myocarditis. Search strategy We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library Issue 3, 2009, MEDLINE (January 1966 - July 2009), EMBASE (January 1998 - July 2009), Chinese Biomedical Database (1979 - 2009), China National Knowledge Infrastructure (1979 - 2009), Chinese VIP Information (1989 - 2009), Chinese Academic Conference Papers Database and Chinese Dissertation Database (1980 - 2009), AMED (1985 - 2009), LILACS accessed in July 2009 and the trials register of the Cochrane Complementary Medicine Field. We handsearched Chinese journals and conference proceedings. No language restrictions were applied. Selection criteria Randomised controlled trials of herbal medicines (with a minimum of seven days treatment duration) compared with placebo, no intervention, or conventional interventions were included. Trials of herbal medicine plus conventional drug versus drug alone were also included. Only trials that reported adequate description of allocation sequence generation were included. Data collection and analysis Two review authors independently extracted data and evaluated trial quality. Adverse effects information was collected from the trials. Main results Fourteen randomised trials involving 1463 people were included. All trials were conducted and published in China. Quality of the trials was assessed to be low. No trial had diagnosis of viral myocarditis confirmed histologically, and only a few trials attempted to establish viral aetiology. Nine different herbal medicines were tested in the included trials. The trials reported electrocardiogram results, level of myocardial enzymes, cardiac function, symptoms, and adverse effects. Astragalus membranaceus (either as an injection or granules) showed significant positive effects in symptom improvement, normalisation of electrocardiogram results, CPK levels, and cardiac function. Shengmai injection also showed significant effects in symptom improvement. Shengmai decoction triggered significant improvement in quality of life measured by SF-36. No serious adverse effects were reported. Authors’ conclusions Some herbal medicines may lead to improvement of symptoms, ventricular premature beat, electrocardiogram, level of myocardial enzymes, and cardiac function in viral myocarditis. However, interpretation of these findings should be taken with care due to the low methodological quality, small sample size, and limited number of trials on individual herbs. Further robust trials are needed to explore the use of herbal medicines in viral myocarditis.

Liu, Zhao Lan; Liu, Zhi Jun; Liu, Jian Ping; Yang, Min; Kwong, Joey

2012-01-01

308

Herbal medicines for viral myocarditis  

PubMed Central

Background Herbal medicines are being used for treating viral diseases including viral myocarditis, and many controlled trials have been done to investigate their efficacy. Objectives To assess the effects of herbal medicines on clinical and indirect outcomes in patients with viral myocarditis. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library Issue 3, 2009, MEDLINE (January 1966 - July 2009), EMBASE (January 1998 - July 2009), Chinese Biomedical Database (1979 - 2009), China National Knowledge Infrastructure (1979 - 2009), Chinese VIP Information (1989 - 2009), Chinese Academic Conference Papers Database and Chinese Dissertation Database (1980 - 2009), AMED (1985 - 2009), LILACS accessed in July 2009 and the trials register of the Cochrane Complementary Medicine Field. We handsearched Chinese journals and conference proceedings. No language restrictions were applied. Selection criteria Randomised controlled trials of herbal medicines (with a minimum of seven days treatment duration) compared with placebo, no intervention, or conventional interventions were included. Trials of herbal medicine plus conventional drug versus drug alone were also included. Only trials that reported adequate description of allocation sequence generation were included. Data collection and analysis Two review authors independently extracted data and evaluated trial quality. Adverse effects information was collected from the trials. Results Fourteen randomised trials involving 1463 people were included. All trials were conducted and published in China. Quality of the trials was assessed to be low. No trial had diagnosis of viral myocarditis confirmed histologically, and only a few trials attempted to establish viral aetiology. Nine different herbal medicines were tested in the included trials. The trials reported electrocardiogram results, level of myocardial enzymes, cardiac function, symptoms, and adverse effects. Astragalus membranaceus (either as an injection or granules) showed significant positive effects in symptom improvement, normalisation of electrocardiogram results, CPK levels, and cardiac function. Shengmai injection also showed significant effects in symptom improvement. Shengmai decoction triggered significant improvement in quality of life measured by SF-36. No serious adverse effects were reported. Authors' conclusions Some herbal medicines may lead to improvement of symptoms, ventricular premature beat, electrocardiogram, level of myocardial enzymes, and cardiac function in viral myocarditis. However, interpretation of these findings should be taken with care due to the low methodological quality, small sample size, and limited number of trials on individual herbs. Further robust trials are needed to explore the use of herbal medicines in viral myocarditis.

Liu, Zhao Lan; Liu, Zhi Jun; Liu, Jian Ping; Yang, Min; Kwong, Joey

2011-01-01

309

RNA silencing suppression by plant pathogens: defence, counter-defence and counter-counter-defence.  

PubMed

RNA silencing is a central regulator of gene expression in most eukaryotes and acts both at the transcriptional level through DNA methylation and at the post-transcriptional level through direct mRNA interference mediated by small RNAs. In plants and invertebrates, the same pathways also function directly in host defence against viruses by targeting viral RNA for degradation. Successful viruses have consequently evolved diverse mechanisms to avoid silencing, most notably through the expression of viral suppressors of RNA silencing. RNA silencing suppressors have also been recently identified in plant pathogenic bacteria and oomycetes, suggesting that disruption of host silencing is a general virulence strategy across several kingdoms of plant pathogens. There is also increasing evidence that plants have evolved specific defences against RNA-silencing suppression by pathogens, providing yet another illustration of the never-ending molecular arms race between plant pathogens and their hosts. PMID:24129510

Pumplin, Nathan; Voinnet, Olivier

2013-10-16

310

Differences in pathogenicity of A/Duck/Vietnam/201/05 H5N1 highly pathogenic avian influenza virus reassortants in ducks  

Technology Transfer Automated Retrieval System (TEKTRAN)

In order to understand which viral genes contribute to the high virulence of A/Dk/Vietnam/201/05 H5N1 highly pathogenic avian influenza (HPAI) virus in ducks, we used reverse genetics to generate single-gene reassortant viruses with genes from A/Ck/Indonesia/7/03, a virus that produces mild disease ...

311

Effect of treating co-infections on HIV-1 viral load: a systematic review  

PubMed Central

Co-infections contribute to HIV-related pathogenesis and often increase viral load in HIV-infected people. We did a systematic review to assess the effect of treating key co-infections on plasma HIV-1-RNA concentrations in low-income countries. We identified 18 eligible studies for review: two on tuberculosis, two on malaria, six on helminths, and eight on sexually transmitted infections, excluding untreatable or non-pathogenic infections. Standardised mean plasma viral load decreased after the treatment of co-infecting pathogens in all 18 studies. The standardised mean HIV viral-load difference ranged from ?0·04 log10 copies per mL (95% CI ?0·24 to 0·16) after syphilis treatment to ?3·47 log10 copies per mL (95% CI ?3·78 to ?3·16) after tuberculosis treatment. Of 14 studies with variance data available, 12 reported significant HIV viral-load differences before and after treatment. Although many of the viral-load reductions were 1·0 log10 copies per mL or less, even small changes in plasma HIV-RNA concentrations have been shown to slow HIV progression and could translate into population-level benefits in lowering HIV transmission risk.

Modjarrad, Kayvon; Vermund, Sten H

2010-01-01

312

Shellfish-borne viral outbreaks: a systematic review.  

PubMed

Investigations of disease outbreaks linked to shellfish consumption have been reported in the scientific literature; however, only few countries systematically collate and report such data through a disease surveillance system. We conducted a systematic review to investigate shellfish-borne viral outbreaks and to explore their distribution in different countries, and to determine if different types of shellfish and viruses are implicated. Six databases (Medline, Embase, Scopus, PubMed, Eurosurveillance Journal and Spingerlink electronic Journal) and a global electronic reporting system (ProMED) were searched from 1980 to July 2012. About 359 shellfish-borne viral outbreaks, alongside with nine ProMED reports, involving shellfish consumption, were identified. The majority of the reported outbreaks were located in East Asia, followed by Europe, America, Oceania, Australia and Africa. More than half of the outbreaks (63.6 %) were reported from Japan. The most common viral pathogens involved were norovirus (83.7 %) and hepatitis A virus (12.8 %). The most frequent type of consumed shellfish which was involved in outbreaks was oysters (58.4 %). Outbreaks following shellfish consumption were often attributed to water contamination by sewage and/or undercooking. Differences in reporting of outbreaks were seen between the scientific literature and ProMED. Consumption of contaminated shellfish represents a risk to public health in both developed and developing countries, but impact will be disproportionate and likely to compound existing health disparities. PMID:23412719

Bellou, M; Kokkinos, P; Vantarakis, A

2012-11-22

313

ISG15 Regulates Peritoneal Macrophages Functionality against Viral Infection  

PubMed Central

Upon viral infection, the production of type I interferon (IFN) and the subsequent upregulation of IFN stimulated genes (ISGs) generate an antiviral state with an important role in the activation of innate and adaptive host immune responses. The ubiquitin-like protein (UBL) ISG15 is a critical IFN-induced antiviral molecule that protects against several viral infections, but the mechanism by which ISG15 exerts its antiviral function is not completely understood. Here, we report that ISG15 plays an important role in the regulation of macrophage responses. ISG15?/? macrophages display reduced activation, phagocytic capacity and programmed cell death activation in response to vaccinia virus (VACV) infection. Moreover, peritoneal macrophages from mice lacking ISG15 are neither able to phagocyte infected cells nor to block viral infection in co-culture experiments with VACV-infected murine embryonic fibroblast (MEFs). This phenotype is independent of cytokine production and secretion, but clearly correlates with impaired activation of the protein kinase AKT in ISG15 knock-out (KO) macrophages. Altogether, these results indicate an essential role of ISG15 in the cellular immune antiviral response and point out that a better understanding of the antiviral responses triggered by ISG15 may lead to the development of therapies against important human pathogens.

Llompart, Catalina; Knobeloch, Klaus-Peter; Gutierrez-Erlandsson, Sylvia; Garcia-Sastre, Adolfo; Esteban, Mariano; Nieto, Amelia; Guerra, Susana

2013-01-01

314

Detection of Foot and Mouth Disease and Porcine Reproductive and Respiratory Syndrome Viral Genes Using Microarray Chip  

Microsoft Academic Search

Two viral pathogens, namely, porcine reproductive and respiratory syndrome virus (PRRSV) and foot and mouth disease virus\\u000a (FMDV), were selected as models for multiple pathogen detection in a cDNA microarray. Two signature regions selected from\\u000a ORF2 (around 500 bp) and ORF5 (around 600 bp) of PRRVS (America serotype), and one signature region from structural genes\\u000a VP1 (around 500 bp) of

Y.-C. Liu; G. S. Huang; M.-C. Wu; M.-Y. Hong; K.-P. Hsiung

2006-01-01

315

Stomata and pathogens  

PubMed Central

Bacteria and fungi are capable of triggering stomatal closure through pathogen-associated molecular patterns (PAMPs), which prevents penetration through these pores. Therefore, the stomata can be considered part of the plant innate immune response. Some pathogens have evolved mechanisms to evade stomatal defense. The bacterial pathogen Xanthomonas campestris pv. campestris (Xcc), which infects plants of the Brassicaceae family mainly through hydathodes, has also been reported to infect plants through stomata. A recent report shows that penetration of Xcc in Arabidopsis leaves through stomata depends on a secreted small molecule whose synthesis is under control of the rpf/diffusible signal factor (DSF) cell-to-cell signaling system, which also controls genes involved in biofilm formation and pathogenesis. The same reports shows that Arabidopsis ROS- and PAMP-activated MAP kinase 3 (MPK3) is essential for stomatal innate response. Other recent and past findings about modulation of stomatal behaviour by pathogens are also discussed. In all, these findings support the idea that PAMP-triggered stomatal closure might be a more effective and widespread barrier against phytopathogens than previously thought, which has in turn led to the evolution in pathogens of several mechanisms to evade stomatal defense.

Gudesblat, Gustavo E; Torres, Pablo S

2009-01-01

316

Evolution of microbial pathogens.  

PubMed Central

Various genetic mechanisms including point mutations, genetic rearrangements and lateral gene transfer processes contribute to the evolution of microbes. Long-term processes leading to the development of new species or subspecies are termed macroevolution, and short-term developments, which occur during days or weeks, are considered as microevolution. Both processes, macro- and microevolution need horizontal gene transfer, which is particularly important for the development of pathogenic microorganisms. Plasmids, bacteriophages and so-called pathogenicity islands (PAIs) play a crucial role in the evolution of pathogens. During microevolution, genome variability of pathogenic microbes leads to new phenotypes, which play an important role in the acute development of an infectious disease. Infections due to Staphylococcus epidermidis, Candida albicans and Escherichia coli will be described with special emphasis on processes of microevolution. In contrast, the development of PAIs is a process involved in macroevolution. PAIs are especially important in processes leading to new pathotypes or even species. In this review, particular attention will be given to the fact that the evolution of pathogenic microbes can be considered as a specific example for microbial evolution in general.

Morschhauser, J; Kohler, G; Ziebuhr, W; Blum-Oehler, G; Dobrindt, U; Hacker, J

2000-01-01

317

Downstream processing of viral vectors and vaccines  

Microsoft Academic Search

Viral vectors and viral vaccines more and more play an important role in current medical approaches. Gene vectors like adenoviruses, adeno-associated viruses or retroviruses are the vehicles being developed for delivering genetic material to the target cell in gene therapy. Viral vaccines, like attenuated or inactivated rabies virus, influenza virus or hepatitis virus vaccines, are powerful tools to limit the

R Morenweiser

2005-01-01

318

Laboratory procedures to generate viral metagenomes  

Microsoft Academic Search

This collection of laboratory protocols describes the steps to collect viruses from various samples with the specific aim of generating viral metagenome sequence libraries (viromes). Viral metagenomics, the study of uncultured viral nucleic acid sequences from different biomes, relies on several concentration, purification, extraction, sequencing and heuristic bioinformatic methods. No single technique can provide an all-inclusive approach, and therefore the

Matthew Haynes; Mya Breitbart; Linda Wegley; Forest Rohwer; Rebecca V Thurber

2009-01-01

319

Viral vectors for malaria vaccine development  

Microsoft Academic Search

A workshop on viral vectors for malaria vaccine development, organized by the PATH Malaria Vaccine Initiative, was held in Bethesda, MD on October 20, 2005. Recent advancements in viral-vectored malaria vaccine development and emerging vector technologies were presented and discussed. Classic viral vectors such as poxvirus, adenovirus and alphavirus vectors have been successfully used to deliver malaria antigens. Some of

Shengqiang Li; Emily Locke; Joseph Bruder; David Clarke; Denise L. Doolan; Menzo J. E. Havenga; Adrian V. S. Hill; Peter Liljestrom; Thomas P. Monath; Hussein Y. Naim; Christian Ockenhouse; De-chu C. Tang; Kent R. Van Kampen; Jean-Francois Viret; Fidel Zavala; Filip Dubovsky

2007-01-01

320

Assessment of Experimental and Natural Viral Aerosols.  

National Technical Information Service (NTIS)

The purpose of these studies was to describe procedures employed in studies on the role of viral aerosols in human viral respiratory disease. The results showed that viral aerosols prepared with the Collison atomizer can be adjusted to a desired content o...

P. J. Gerone R. B. Couch G. V. Keefer R. G. Douglas E. B. Derrenbacher

1966-01-01

321

Pathogenicity Induced by Feline Leukemia Virus, Rickard Strain, Subgroup A Plasmid DNA (pFRA)  

Microsoft Academic Search

A new provirus clone of feline leukemia virus (FeLV), which we named FeLV-A (Rickard) or FRA, was characterized with respect to viral interference group, host range, complete genome sequence, and in vivo pathogenicity in specific-pathogen-free newborn cats. The in vitro studies indicated the virus to be an ecotropic subgroup A FeLV with 98% nucleotide sequence homology to another FeLV-A clone

HANG CHEN; MARTA K. BECHTEL; YAN SHI; ANDREW PHIPPS; LAWRENCE E. MATHES; KATHLEEN A. HAYES; PRADIP ROY-BURMAN

1998-01-01

322

A study on pathogens of Chinese prawn ( Penaeus Chinensis) virus diseases  

NASA Astrophysics Data System (ADS)

This pathogenic study shows that the viral diseases of Chinese prawns ( Penaeus chinensis, O'sbeck) is due to three kinds of viruses: epithelium envelope baculovirus of Penaeus chinensis (EEBV-PC, detected by the authors in 1993), infections hypodermal and hematopoietic necrosis virus, and hepatopancreatic parvo-like virus, and that the first two viruses seem to be the main pathogens of the epidemic in the northern regions in 1993.

Sun, Xiu-Qin; Zhang, Jin-Xing

1995-09-01

323

Increased Tolerance to Two Oomycete Pathogens in Transgenic Tobacco Expressing Pathogenesis-Related Protein 1a  

Microsoft Academic Search

Expression of pathogenesis-related protein 1a (PR-1a), a protein of unknown biochemical function, is induced to high levels in tobacco in response to pathogen infection. The induction of PR-1a expression is tightly correlated with the onset of systemic acquired resistance (SAR), a defense response effective against a variety of fungal, viral, and bacterial pathogens. While PR-1a has been postulated to be

Danny Alexander; Robert M. Goodman; Manuela Gut-Rella; Christopher Glascock; Kristianna Weymann; Leslie Friedrich; Daryl Maddox; Patricia Ahl-Goy; Tom Luntz; Eric Ward; John Ryals

1993-01-01

324

The role of Rel/NF-kappa B proteins in viral oncogenesis and the regulation of viral transcription.  

PubMed

Rel/NF-kappa B is a ubiquitous transcription factor that consists of multiple polypeptide subunits, and is subject to complex regulatory mechanisms that involve protein-protein interactions, phosphorylation, ubiquitination, proteolytic degradation, and nucleocytoplasmic translocation. The sophisticated control of Rel/NF-kappa B activity is not surprising since this transcription factor is involved in a wide array of cellular responses to extracellular cues, associated with growth, development, apoptosis, and pathogen invasion. Thus, it is not unexpected that this versatile cellular homeostatic switch would be affected by a variety of viral pathogens, which have evolved mechanisms to utilize various aspects of Rel/NF-kappa B activity to facilitate their replication, cell survival and possibly evasion of immune responses. This review will cover the molecular mechanisms that are utilized by mammalian oncogenic viruses to affect the activity of Rel/NF-kappa B transcription factors and the role of Rel/NF-kappa B in the regulation of viral gene expression and replication. PMID:9299590

Mosialos, G

1997-04-01

325

Viral Infections of the Central Nervous System: A Case-Based Review  

PubMed Central

Three patients with viral infections of the central nervous system (CNS) were evaluated on an inpatient infectious diseases consultation service within a two-week period. These cases, caused by herpes simplex virus, varicella zoster virus and enterovirus, highlight the importance of viral pathogens in causing debilitating infections of the CNS and provide examples of the utility of molecular diagnostics in evaluating patients with encephalitis and meningitis. The importance of antiviral therapy is particularly underscored by these cases, as is the variability in response of patients to such agents.

Big, Cecilia; Reineck, Lora A.; Aronoff, David M.

2009-01-01

326

Early In Vitro Transcription Termination in Human H5 Influenza Viral RNA Synthesis  

Microsoft Academic Search

Rapid diagnostic identification of the human H5 influenza virus is a strategic cornerstone for outbreak prevention. We recently\\u000a reported a method for direct detection of viral RNA from a highly pathogenic human H5 influenza strain (A\\/Hanoi\\/30408\\/2005(H5N1)),\\u000a which necessarily was transcribed in vitro from non-viral sources. This article provides an in-depth analysis of the reaction\\u000a conditions for in vitro transcription (IVT)

Matthew B. Kerby; Aartik A. Sarma; Madhukar S. Patel; Andrew W. Artenstein; Steven M. Opal; Anubhav Tripathi

2011-01-01

327

Candida albicans pathogenicity mechanisms  

PubMed Central

The polymorphic fungus Candida albicans is a member of the normal human microbiome. In most individuals, C. albicans resides as a lifelong, harmless commensal. Under certain circumstances, however, C. albicans can cause infections that range from superficial infections of the skin to life-threatening systemic infections. Several factors and activities have been identified which contribute to the pathogenic potential of this fungus. Among them are molecules which mediate adhesion to and invasion into host cells, the secretion of hydrolases, the yeast-to-hypha transition, contact sensing and thigmotropism, biofilm formation, phenotypic switching and a range of fitness attributes. Our understanding of when and how these mechanisms and factors contribute to infection has significantly increased during the last years. In addition, novel virulence mechanisms have recently been discovered. In this review we present an update on our current understanding of the pathogenicity mechanisms of this important human pathogen.

Mayer, Francois L.; Wilson, Duncan; Hube, Bernhard

2013-01-01

328

Histone deacetylases in viral infections  

Microsoft Academic Search

Chromatin remodeling and gene expression are regulated by histone deacetylases (HDACs) that condense the chromatin structure\\u000a by deacetylating histones. HDACs comprise a group of enzymes that are responsible for the regulation of both cellular and\\u000a viral genes at the transcriptional level. In mammals, a total of 18 HDACs have been identified and grouped into four classes,\\u000a i.e., class I (HDACs

Georges Herbein; Daniel Wendling

2010-01-01

329

Autistic disorder and viral infections  

Microsoft Academic Search

Autistic disorder (autism) is a behaviorally defined developmental disorder with a wide range of behaviors. Although the etiology\\u000a of autism is unknown, data suggest that autism results from multiple etiologies with both genetic and environmental contributions,\\u000a which may explain the spectrum of behaviors seen in this disorder. One proposed etiology for autism is viral infection very\\u000a early in development. The

Jane E. Libbey; Thayne L. Sweeten; William M. McMahon; Robert S. Fujinami

2005-01-01

330

Treatment of Acute Viral Bronchiolitis  

PubMed Central

Acute viral bronchiolitis represents the most common lower respiratory tract infection in infants and young children and is associated with substantial morbidity and mortality. Respiratory syncytial virus is the most frequently identified virus, but many other viruses may also cause acute bronchiolitis. There is no common definition of acute viral bronchiolitis used internationally, and this may explain part of the confusion in the literature. Most children with bronchiolitis have a self limiting mild disease and can be safely managed at home with careful attention to feeding and respiratory status. Criteria for referral and admission vary between hospitals as do clinical practice in the management of acute viral bronchiolitis, and there is confusion and lack of evidence over the best treatment for this condition. Supportive care, including administration of oxygen and fluids, is the cornerstone of current treatment. The majority of infants and children with bronchiolitis do not require specific measures. Bronchodilators should not be routinely used in the management of acute viral bronchiolitis, but may be effective in some patients. Most of the commonly used management modalities have not been shown to have a clear beneficial effect on the course of the disease. For example, inhaled and systemic corticosteroids, leukotriene receptor antagonists, immunoglobulins and monoclonal antibodies, antibiotics, antiviral therapy, and chest physiotherapy should not be used routinely in the management of bronchiolitis. The potential effect of hypertonic saline on the course of the acute disease is promising, but further studies are required. In critically ill children with bronchiolitis, today there is little justification for the use of surfactant and heliox. Nasal continuous positive airway pressure may be beneficial in children with severe bronchiolitis but a large trial is needed to determine its value. Finally, very little is known on the effect of the various interventions on the development of post-bronchiolitic wheeze.

Eber, Ernst

2011-01-01

331

Persistence of Highly Pathogenic Avian Influenza Viruses in Natural Ecosystems  

PubMed Central

Understanding of ecologic factors favoring emergence and maintenance of highly pathogenic avian influenza (HPAI) viruses is limited. Although low pathogenic avian influenza viruses persist and evolve in wild populations, HPAI viruses evolve in domestic birds and cause economically serious epizootics that only occasionally infect wild populations. We propose that evolutionary ecology considerations can explain this apparent paradox. Host structure and transmission possibilities differ considerably between wild and domestic birds and are likely to be major determinants of virulence. Because viral fitness is highly dependent on host survival and dispersal in nature, virulent forms are unlikely to persist in wild populations if they kill hosts quickly or affect predation risk or migratory performance. Interhost transmission in water has evolved in low pathogenic influenza viruses in wild waterfowl populations. However, oropharyngeal shedding and transmission by aerosols appear more efficient for HPAI viruses among domestic birds.

Feare, Chris J.; Renaud, Francois; Thomas, Frederic; Gauthier-Clerc, Michel

2010-01-01

332

Sudden Deafness: Is It Viral?  

PubMed Central

A number of theories have been proposed to explain the etiopathogenesis of idiopathic sudden sensorineural hearing loss (ISSHL), including viral infection, vascular occlusion, breaks of labyrinthine membranes, immune-mediated mechanisms and abnormal cellular stress responses within the cochlea. In the present paper, we provide a critical review of the viral hypothesis of ISSHL. The evidence reviewed includes published reports of epidemiological and serological studies, clinical observations and results of antiviral therapy, morphological and histopathological studies, as well as results of animal experiments. The published evidence does not satisfy the majority of the Henle-Koch postulates for viral causation of an infectious disease. Possible explanations as to why these postulates remain unfulfilled are reviewed, and future studies that may provide more insight are described. We also discuss other mechanisms that have been postulated to explain ISSHL. Our review indicates that vascular occlusion, labyrinthine membrane breaks and immune-mediated mechanisms are unlikely to be common causes of ISSHL. Finally, we review our recently proposed theory that abnormal cellular stress responses within the cochlea may be responsible for ISSHL.

Merchant, Saumil N.; Durand, Marlene L.; Adams, Joe C.

2008-01-01

333

Aptamers: Novel Molecules as Diagnostic Markers in Bacterial and Viral Infections?  

PubMed Central

Worldwide the entire human population is at risk of infectious diseases of which a high degree is caused by pathogenic protozoans, worms, bacteria, and virus infections. Moreover the current medications against pathogenic agents are losing their efficacy due to increasing and even further spreading drug resistance. Therefore, there is an urgent need to discover novel diagnostic as well as therapeutic tools against infectious agents. In view of that, the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) represents a powerful technology to target selectively pathogenic factors as well as entire bacteria or viruses. SELEX uses a large combinatorial oligonucleic acid library (DNA or RNA) which is processed a by high-flux in vitro screen of iterative cycles. The selected ligands, termed aptamers, are characterized by high specificity and affinity to their target molecule, which are already exploited in diagnostic and therapeutic applications. In this minireview we will discuss the current status of the SELEX technique applied on bacterial and viral pathogens.

Zimbres, Flavia M.; Tarnok, Attila; Ulrich, Henning

2013-01-01

334

[Etiological agent and pathogenicity mechanism of PML].  

PubMed

JC virus (JCV) is a causative agent of progressive multifocal leukoencephalopathy (PML) that occurs mainly in immunosuppressed patients, especially those with HIV/AIDS. JCV belongs to the Polyomavirus that are characterized by non-enveloped icosahedral capsids containing small, circular, double-stranded DNA genomes. JCV is widely distributed among the population world-wide. However, infections are usually restricted by the immune system. In this article we briefly provide an overview of the interaction between JCV and host immunity. We also review the biological and physical characteristics and the lifecycle, receptors interaction, intracellular trafficking, viral transcription and replication, progeny virus propagation of JCV to examine the pathogenicity mechanism of PML. PMID:17695290

Suzuki, Tadaki; Nagashima, Kazuo; Sawa, Hirofumi

2007-08-01

335

Molecular Engineering of Viral Gene Delivery Vehicles  

PubMed Central

Viruses can be engineered to efficiently deliver exogenous genes, but their natural gene delivery properties often fail to meet human therapeutic needs. Therefore, engineering viral vectors with new properties, including enhanced targeting abilities and resistance to immune responses, is a growing area of research. This review discusses protein engineering approaches to generate viral vectors with novel gene delivery capabilities. Rational design of viral vectors has yielded successful advances in vitro, and to an extent in vivo. However, there is often insufficient knowledge of viral structure-function relationships to reengineer existing functions or create new capabilities, such as virus-cell interactions, whose molecular basis is distributed throughout the primary sequence of the viral proteins. Therefore, high-throughput library and directed evolution methods offer alternative approaches to engineer viral vectors with desired properties. Parallel and integrated efforts in rational and library-based design promise to aid the translation of engineered viral vectors toward the clinic.

Schaffer, David V.; Koerber, James T.; Lim, Kwang-il

2009-01-01

336

Post-infective and chronic fatigue syndromes precipitated by viral and non-viral pathogens: prospective cohort study  

Microsoft Academic Search

Objective To delineate the risk factors, symptom patterns, and longitudinal course of prolonged illnesses after a variety of acute infections. Design Prospective cohort study following patients from the time of acute infection with Epstein-Barr virus (glandular fever), Coxiella burnetii (Q fever), or Ross River virus (epidemic polyarthritis). Setting The region surrounding the township of Dubbo in rural Australia, encompassing a

Ian Hickie; Tracey Davenport; Denis Wakefield; Ute Vollmer-Conna; Barbara Cameron; Suzanne D Vernon; William C

2006-01-01

337

Viral Control of Mitochondrial Apoptosis  

Microsoft Academic Search

Throughout the process of pathogen–host co-evolution, viruses have developed a battery of distinct strategies to overcome biochemical and immunological defenses of the host. Thus, viruses have acquired the capacity to subvert host cell apoptosis, control inflammatory responses, and evade immune reactions. Since the elimination of infected cells via programmed cell death is one of the most ancestral defense mechanisms against

Lorenzo Galluzzi; Catherine Brenner; Eugenia Morselli; Zahia Touat; Guido Kroemer

2008-01-01

338

PATHOGEN EQUIVALENCY COMMITTEE (PEC)  

EPA Science Inventory

The U.S. Environmental Protection Agency created the PEC in 1985 to make recommendations to EPA and State managers on the equivalency of unproven sewage sludge disinfection technologies/processes to either a Process to Significantly Reduce Pathogens (PSRP) or a Process to Further...

339

DISINFECTION OF EMERGING PATHOGENS  

EPA Science Inventory

There is a growing awareness of the need to control waterborne microbial pathogens. This presentation will concentate on the role of chemical inactivation, using chlorine, chloramines and ozone as a means of controlling bacterial and protozoan species. Information will be present...

340

The pathogenic equine streptococci  

Microsoft Academic Search

Streptococci pathogenic for the horse include S. equi (S. equi subsp. equi), S. zooepidemicus (S. equi subsp. zooepidemicus), S. dysgalactiae subsp. equisimilis and S. pneumoniae capsule Type III. S. equi is a clonal descendent or biovar of an ancestral S. zooepidemicus strain with which it shares greater than 98% DNA homology and therefore expresses many of the same proteins and

John F. Timoney

2004-01-01

341

Recombinant protein-based viral disease diagnostics in veterinary medicine.  

PubMed

Identification of pathogens or antibody response to pathogens in human and animals modulates the treatment strategies for naive population and subsequent infections. Diseases can be controlled and even eradicated based on the epidemiology and effective prophylaxis, which often depends on development of efficient diagnostics. In addition, combating newly emerging diseases in human as well as animal healthcare is challenging and is dependent on developing safe and efficient diagnostics. Detection of antibodies directed against specific antigens has been the method of choice for documenting prior infection. Other than zoonosis, development of inexpensive vaccines and diagnostics is a unique problem in animal healthcare. The advent of recombinant DNA technology and its application in the biotechnology industry has revolutionized animal healthcare. The use of recombinant DNA technology in animal disease diagnosis has improved the rapidity, specificity and sensitivity of various diagnostic assays. This is because of the absence of host cellular proteins in the recombinant derived antigen preparations that dramatically decrease the rate of false-positive reactions. Various recombinant products are used for disease diagnosis in veterinary medicine and this article discusses recombinant-based viral disease diagnostics currently used for detection of pathogens in livestock and poultry. PMID:20843198

Balamurugan, Vinayagamurthy; Venkatesan, Gnanavel; Sen, Arnab; Annamalai, Lakshmanan; Bhanuprakash, Veerakyathappa; Singh, Raj Kumar

2010-09-01

342

ANALYSIS OF CELL SIGNALING PATHWAYS AFTER INFECTION WITH BOVINE VIRAL DIARRHEA VIRUS TYPE 2 USING FLOW CYTOMETRIC TECHNIQUES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bovine viral diarrhea virus (BVDV), a pestivirus of the Flaviviridae family, is an economically important cattle pathogen with a world wide distribution. Based on their behavior in permissive epithelial cell cultures two different biotypes can be distinguished. While cells infected with a noncytopat...

343

Noncytopathogenic bovine viral diarrhea virus (BVDV) reduces cleavage but increases blastocyst yield of in vitro produced embryos  

Microsoft Academic Search

The growing application of in vitro embryo production systems that utilize slaughterhouse tissues of animals of unknown health status conveys the risk of disease transmission. One pathogen of concern in this regard is bovine viral diarrhea virus (BVDV), and the objective of this study was to investigate the effect of BVDV on in vitro embryonic development. A bovine in vitro

P. J. Booth; M. E Collins; L Jenner; H Prentice; J Ross; J. H Badsberg; J Brownlie

1998-01-01

344

Experimental depletion of CD8+ cells in acutely SIVagm-Infected African Green Monkeys results in increased viral replication  

Microsoft Academic Search

BACKGROUND: In vivo CD8+ cell depletions in pathogenic SIV infections identified a key role for cellular immunity in controlling viral load (VL) and disease progression. However, similar studies gave discordant results in chronically-infected SMs, leading some authors to propose that in natural hosts, SIV replication is independent of cellular immunity. To assess the role of cellular immune responses in the

Thaidra Gaufin; Ruy M Ribeiro; Rajeev Gautam; Jason Dufour; Daniel Mandell; Cristian Apetrei; Ivona Pandrea

2010-01-01

345

Viral diseases of penaeid shrimp with particular reference to four viruses recently found in shrimp from Queensland  

Microsoft Academic Search

The culture of penaeid shrimp world-wide is primarily dependent on wild-caught broodstock which has an enormous potential to introduce new pathogens, particularly viruses, into culture systems. Of the 13 viruses described for cultured penaeid shrimp, seven have been described within the past 5 years; the most devastating viral epidemics on record for cultured penaeid shrimp have also occurred within the

K. M. Spann; R. J. G. Lester

1997-01-01

346

Comparison of the immune response between a pair of NCP and CP bovine viral diarrhea virus (BVDV) type 1 isolates  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bovine viral diarrhea virus (BVDV) is a major pathogen of cattle causing severe respiratory and reproductive disease. BVDV vaccines remain an important part of the control strategy. Previous work has described higher antibody responses in animals infected with a noncytopathic (NCP) BVDV when compa...

347

Surface-enhanced Raman scattering (SERS) detection of multiple viral antigens using magnetic capture of SERS-active nanoparticles.  

Technology Transfer Automated Retrieval System (TEKTRAN)

A highly sensitive immunoassay based on surface-enhanced Raman scattering (SERS) spectroscopy has been developed for multiplex detection of surface envelope and capsid antigens of the viral zoonotic pathogens West Nile virus (WNV) and Rift Valley fever virus (RVFV). Detection was mediated by antibo...

348

Development of Vaccinia reporter viruses for rapid, high content analysis of viral function at all stages of gene expression  

Microsoft Academic Search

Vaccinia virus is the prototypical orthopoxvirus of Poxviridae, a family of viruses that includes the human pathogens Variola (smallpox) and Monkeypox. Core viral functions are conserved among orthopoxviruses, and consequently Vaccinia is routinely used to study poxvirus biology and screen for novel antiviral compounds. Here we describe the development of a series of fluorescent protein-based reporter Vaccinia viruses that provide

Ken Dower; Kathleen H. Rubins; Lisa E. Hensley; John H. Connor

2011-01-01

349

Drug Sanctuaries, Low Steady State Viral Loads and Viral Blips.  

SciTech Connect

Patients on HAART for long periods of time obtain viral loads (VLs) below 50 copies/ml. Ultrasensitive VL assays show that some of these patients obtain a low steady state VL, while others continue to exhibit VL declines to below 5 copies/ml. Low steady states can be explained by two-compartment models that incorporate a drug sanctuary. Interestingly, when patients exhibit continued declines below 50 copies/ml the rate of decline has a half-life of {approx} 6 months, consistent with some estimates of the rate of latent cell decline. Some patients, despite having sustained undetectable VLs show periods of transient viremia (blips). I will present some statistical characterization of the blips observed in a set of 123 patients, suggesting that blips are generated largely by random processes, that blips tend to correspond to periods of a few weeks in which VLs are elevated, and that VL decay from the peak of a blip may have two-phases. Using new results suggesting that the viral burst size, N {approx} 5 x 10{sup 4}, we estimate the number of cells needed to produce a blip.

Perelson, Alan S.,; Callaway, D. (Duncan); Pomerantz, R. J. (Roger J.); Chen, H. Y.; Markowitz, M.; Ho, David D.; Di Mascio, M. (Michele)

2002-01-01

350

Survey of Salmonid Pathogens in Ocean-Caught Fishes in British Columbia, Canada  

Microsoft Academic Search

A survey of wild fishes captured around marine net-pen salmon farms and from open waters for certain salmonid pathogens was conducted in the coastal waters of British Columbia. Viral hemorrhagic septicemia virus was detected in Pacific herring Clupea pallasi, shiner perch Cymatogaster aggregata, and threespine sticklebacks Gasterosteus aculeatus. Infectious hematopoietic necrosis (IHN) virus was detected in one Pacific herring (collected

M. L. Kent; G. S. Traxler; D. Kieser; J. Richard; S. C. Dawe; R. W. Shaw; G. Prosperi-Porta; J. Ketcheson; T. P. T. Evelyn

1998-01-01

351

Use of specific-pathogen-free (SPF) rhesus macaques to better model oral pediatric cytomegalovirus infection  

PubMed Central

Congenital human cytomegalovirus (HCMV) infection can result in lifelong neurological deficits. Seronegative pregnant woman often acquire primary HCMV from clinically asymptomatic, but HCMV-shedding children. Potential age-related differences in viral and immune parameters of primary RhCMV infection were examined in an oral rhesus CMV infection model in specific pathogen free macaques.

dela Pena, Myra Grace; Strelow, Lisa; Barry, Peter A.

2012-01-01

352

TransCellular Introduction of HIV1 Protein Nef Induces Pathogenic Response in Caenorhabditis elegans  

Microsoft Academic Search

BackgroundCaenorhabditis elegans has emerged as a very powerful model for studying the host pathogen interactions. Despite the absence of a naturally occurring viral infection for C. elegans, the model is now being exploited experimentally to study the basic aspects of virus-host interplay. The data generated from recent studies suggests that the virus that infects mammalian cells does infect, replicate and

Aamir Nazir; Shreesh Raj Sammi; Pankaj Singh; Raj Kamal Tripathi; Cheryl A. Stoddart

2010-01-01

353

Structural and Biochemical Analysis of Human Pathogenic Astrovirus Serine Protease at 2.0 Å Resolution  

Microsoft Academic Search

Astroviruses are single-stranded RNA viruses with a replication strategy based on the proteolytic processing of a polyprotein precursor and subsequent release of the viral enzymes of replication. So far, the catalytic properties of the astrovirus protease as well as its structure have remained uncharacterized. In this study, the three-dimensional crystal structure of the predicted protease of human pathogenic astrovirus has

Silvia Speroni; Jacques Rohayem; Simone Nenci; Daniele Bonivento; Ivonne Robel; Julia Barthel; Victor B. Luzhkov; Bruno Coutard; Bruno Canard; Andrea Mattevi

2009-01-01

354

Immediate early responses of avian tracheal epithelial cells to infection with highly pathogenic avian invluenza virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

Highly pathogenic (HP) avian influenza viruses (AIV) present an ongoing threat to the world poultry industry. In order to develop new AIV control strategies it is necessary to understand the underlying mechanism of viral infection at mucosal respiratory sites. Chicken and duck tracheal epithelial ...

355

Immediate early responses of avian tracheal epithelial cells to infection with highly pathogenic avian influenza  

Technology Transfer Automated Retrieval System (TEKTRAN)

Highly pathogenic (HP) avian influenza viruses (AIV) present an on going threat to the U.S. poultry industry. In order to develop new AIV control strategies it is necessary to understand the underlying mechanism of viral infection. Because the early events of AIV infection can occur on tracheal ep...

356

The contribution of molecular epidemiology to the understanding and control of viral diseases of salmonid aquaculture  

PubMed Central

Molecular epidemiology is a science which utilizes molecular biology to define the distribution of disease in a population (descriptive epidemiology) and relies heavily on integration of traditional (or analytical) epidemiological approaches to identify the etiological determinants of this distribution. The study of viral pathogens of aquaculture has provided many exciting opportunities to apply such tools. This review considers the extent to which molecular epidemiological studies have contributed to better understanding and control of disease in aquaculture, drawing on examples of viral diseases of salmonid fish of commercial significance including viral haemorrhagic septicaemia virus (VHSV), salmonid alphavirus (SAV) and infectious salmon anaemia virus (ISAV). Significant outcomes of molecular epidemiological studies include: Improved taxonomic classification of viruses A better understanding of the natural distribution of viruses An improved understanding of the origins of viral pathogens in aquaculture An improved understanding of the risks of translocation of pathogens outwith their natural host range An increased ability to trace the source of new disease outbreaks Development of a basis for ensuring development of appropriate diagnostic tools An ability to classify isolates and thus target future research aimed at better understanding biological function While molecular epidemiological studies have no doubt already made a significant contribution in these areas, the advent of new technologies such as pyrosequencing heralds a quantum leap in the ability to generate descriptive molecular sequence data. The ability of molecular epidemiology to fulfil its potential to translate complex disease pathways into relevant fish health policy is thus unlikely to be limited by the generation of descriptive molecular markers. More likely, full realisation of the potential to better explain viral transmission pathways will be dependent on the ability to assimilate and analyse knowledge from a range of more traditional information sources. The development of methods to systematically record and share such epidemiologically important information thus represents a major challenge for fish health professionals in making the best future use of molecular data in supporting fish health policy and disease control.

2011-01-01

357

Direct association between pharyngeal viral secretion and host cytokine response in severe pandemic influenza  

PubMed Central

Background Severe disease caused by 2009 pandemic influenza A/H1N1virus is characterized by the presence of hypercytokinemia. The origin of the exacerbated cytokine response is unclear. As observed previously, uncontrolled influenza virus replication could strongly influence cytokine production. The objective of the present study was to evaluate the relationship between host cytokine responses and viral levels in pandemic influenza critically ill patients. Methods Twenty three patients admitted to the ICU with primary viral pneumonia were included in this study. A quantitative PCR based method targeting the M1 influenza gene was developed to quantify pharyngeal viral load. In addition, by using a multiplex based assay, we systematically evaluated host cytokine responses to the viral infection at admission to the ICU. Correlation studies between cytokine levels and viral load were done by calculating the Spearman correlation coefficient. Results Fifteen patients needed of intubation and ventilation, while eight did not need of mechanical ventilation during ICU hospitalization. Viral load in pharyngeal swabs was 300 fold higher in the group of patients with the worst respiratory condition at admission to the ICU. Pharyngeal viral load directly correlated with plasma levels of the pro-inflammatory cytokines IL-6, IL-12p70, IFN-?, the chemotactic factors MIP-1?, GM-CSF, the angiogenic mediator VEGF and also of the immuno-modulatory cytokine IL-1ra (p < 0.05). Correlation studies demonstrated also the existence of a significant positive association between the levels of these mediators, evidencing that they are simultaneously regulated in response to the virus. Conclusions Severe respiratory disease caused by the 2009 pandemic influenza virus is characterized by the existence of a direct association between viral replication and host cytokine response, revealing a potential pathogenic link with the severe disease caused by other influenza subtypes such as H5N1.

2011-01-01

358

Diagnosing norovirus-associated infectious intestinal disease using viral load  

PubMed Central

Background Reverse transcription-polymerase chain reaction (RT-PCR) is the main method for laboratory diagnosis of norovirus-associated infectious intestinal disease (IID). However, up to 16% of healthy individuals in the community, with no recent history of IID, may be RT-PCR positive; so it is unclear whether norovirus is actually the cause of illness in an IID case when they are RT-PCR positive. It is important to identify the pathogen causing illness in sporadic IID cases, for clinical management and for community based incidence studies. The aim of this study was to investigate how faecal viral load can be used to determine when norovirus is the most likely cause of illness in an IID case. Methods Real-time RT-PCR was used to determine the viral load in faecal specimens collected from 589 IID cases and 159 healthy controls, who were infected with genogroup II noroviruses. Cycle threshold (Ct) values from the real-time RT-PCR were used as a proxy measure of viral load. Receiver-operating characteristic (ROC) analysis was used to identify a cut-off in viral load for attributing illness to norovirus in IID cases. Results One hundred and sixty-nine IID cases and 159 controls met the inclusion criteria for the ROC analysis. The optimal Ct value cut-off for attributing IID to norovirus was 31. The same cut-off was selected when using healthy controls, or IID cases who were positive by culture for bacterial pathogens, as the reference negative group. This alternative reference negative group can be identified amongst specimens routinely received in clinical virology laboratories. Conclusion We demonstrated that ROC analysis can be used to select a cut-off for a norovirus real time RT-PCR assay, to aid clinical interpretation and diagnose when norovirus is the cause of IID. Specimens routinely received for diagnosis in clinical virology laboratories can be used to select an appropriate cut-off. Individual laboratories can use this method to define in-house cut-offs for their assays, to provide the best possible diagnostic service to clinicians and public health workers. Other clinical and epidemiological information should also be considered for patients with Ct values close to the cut-off, for the most accurate diagnosis of IID aetiology.

2009-01-01

359

Genome-wide RNAi screen for viral replication in mammalian cell culture.  

PubMed

Influenza infections are considered a global threat to public health and cause seasonal epidemics and recurring pandemics. High mutation rates facilitate the generation of viral escape mutants rendering vaccines and drugs directed against virus-encoded targets ineffective. One alternative approach that could prevent viral escape is the targeting of host cell determinants that are temporarily dispensable for the host but crucial for virus replication. Here, we report a genome-wide RNAi screening approach in mammalian cell culture system that led us to the identification of several host cell genes influencing influenza A virus replication. Interestingly, the majority of the identified host gene products are indispensable for viral replication of a broad range of influenza viruses ranging from the highly pathogenic avian H5N1 strain to the current pandemic swine-origin H1N1 strain. Our results provide a new approach to explore virus-host interactions and to identify promising antiviral targets. PMID:21431699

Prusty, Bhupesh K; Karlas, Alexander; Meyer, Thomas F; Rudel, Thomas

2011-01-01

360

Broad action of Hsp90 as a host chaperone required for viral replication  

PubMed Central

Viruses are intracellular pathogens responsible for a vast number of human diseases. Due to their small genome size, viruses rely primarily on the biosynthetic apparatus of the host for their replication. Recent work has shown that the molecular chaperone Hsp90 is nearly universally required for viral protein homeostasis. As observed for many endogenous cellular proteins, numerous different viral proteins have been shown to require Hsp90 for their folding, assembly, and maturation. Importantly, the unique characteristics of viral replication cause viruses to be hypersensitive to Hsp90 inhibition, thus providing a novel therapeutic avenue for the development of broad-spectrum antiviral drugs. The major developments in this emerging field are hereby discussed.

Geller, Ron; Taguwa, Shuhei; Frydman, Judith

2012-01-01

361

Association of HLA-Alleles with the Immune Regulation of Chronic Viral Infections  

PubMed Central

Cytotoxic CD8 T lymphocytes (CTLs) have an astonishing ability to eliminate pathogen-infected cells. However, if uncontrolled, these CTLs could cause devastating pathology to host tissues. CD8+ effector T cells, therefore, interact with antigen-presenting cells and other immune cells, such as regulatory T cells (Tregs), to regulate further on-site expansion and differentiation of the effector cells. This ensures protection of the host with minimal bystander pathological consequences. During prolonged chronic infections CTLs, however, often lose effector function. Induction of multiple inhibitory pathways is emerging as a major regulator converting effector CTLs into exhausted CTLs during chronic viral infections such as HIV, HCV and HBV. The mechanisms involved in induction of exhaustion during chronic viral infections are the focus of this article. Blockade of inhibitory pathways could potentially restore functional capabilities to exhausted CTLs and represents a potential immune-based intervention in chronic viral infections.

Elahi, Shokrollah; Horton, Helen

2012-01-01

362

The Impact of Respiratory Viral Infection on Wheezing Illnesses and Asthma Exacerbations  

PubMed Central

The etiology and morbidity associated with asthma are thought to stem from both genetic factors and potentially modifiable environmental factors, such as viral infections.[1-7] Although it is unclear whether respiratory viral infections cause asthma, observational studies have demonstrated a high rate of asthma in children with a history of severe viral lower respiratory tract infections during infancy, and viruses are the associated with the majority of asthma exacerbations among both children and adults. This review will discuss the pathogens associated with virus-induced wheezing illnesses during infancy and early childhood, the association of bronchiolitis during infancy with an increased risk of childhood asthma, and the association of respiratory viruses with asthma exacerbations in older children and adults.

Carroll, Kecia N.; Hartert, Tina V.

2008-01-01

363

Pathogenicity and Classification of Staphylococci.  

National Technical Information Service (NTIS)

An important pathogenic property was found in the power to coagulate citrated blood. This ability is possessed only by staph. from purulent processes. The biochemical activity or pathogenicity generally has a parallel ascent with the appearance of hemolys...

J. V. Daranyi

1968-01-01

364

APDS: Autonomous Pathogen Detection System.  

National Technical Information Service (NTIS)

An early warning system to counter bioterrorism, the Autonomous Pathogen Detection System (APDS) continuously monitors the environment for the presence of biological pathogens (e.g., anthrax) and once detected, it sounds an alarm much like a smoke detecto...

R. G. Langlois S. Brown K. Burris B. Colston L. Jones

2002-01-01

365

Viral Vaccines and CTL Response  

PubMed Central

Immune induction by successful vaccine formulations seems to involve stimulation of both humoral and cellular arms of immunity. Nevertheless, CD8+ CTLs are of critical relevance in the context of intracellular infection and tumor for many reasons. The task of exerting antipathogen activity by CD8+ T cells, which principally function to control and eradicate intracellular pathogens, is enabled by constitutive expression of MHC class-I molecules on all tissue types. CTL induction offers hope for vaccines against pathogens that are resistant to neutralizing activity. This review discusses the mechanism of immune induction by some successful vaccines and based on the accrued evidence suggests ideas for improved design of CTL-inducing vaccines.

Woolard, Stacie N.; Kumaraguru, Uday

2010-01-01

366

Viral vaccines and CTL response.  

PubMed

Immune induction by successful vaccine formulations seems to involve stimulation of both humoral and cellular arms of immunity. Nevertheless, CD8+ CTLs are of critical relevance in the context of intracellular infection and tumor for many reasons. The task of exerting antipathogen activity by CD8+ T cells, which principally function to control and eradicate intracellular pathogens, is enabled by constitutive expression of MHC class-I molecules on all tissue types. CTL induction offers hope for vaccines against pathogens that are resistant to neutralizing activity. This review discusses the mechanism of immune induction by some successful vaccines and based on the accrued evidence suggests ideas for improved design of CTL-inducing vaccines. PMID:20379365

Woolard, Stacie N; Kumaraguru, Uday

2010-03-31

367

Cucumber necrosis virus p20 is a viral suppressor of RNA silencing  

Microsoft Academic Search

The p20 protein encoded by the tombusvirus, Cucumber necrosis virus has previously been shown to be involved in host pathogenicity and shares sequence similarity with the Tomato bushy stunt virus p19 suppressor of silencing. Using a virus-induced gene silencing (VIGS) assay, we show that p20 is a viral suppressor of RNA silencing (VSR) in infected plants. In addition, a CNV

Xingan Hao; Amy Lu; Nadia Sokal; Basdeo Bhagwat; Earnest Leung; Rui Mao; Ron Reade; Yunfeng Wu; D’Ann Rochon; Yu Xiang

2011-01-01

368

Metagenomic Analysis of the Viral Flora of Pine Marten and European Badger Feces  

PubMed Central

A thorough understanding of the diversity of viruses in wildlife provides epidemiological baseline information about potential pathogens. Metagenomic analysis of the enteric viral flora revealed a new anellovirus and bocavirus species in pine martens and a new circovirus-like virus and geminivirus-related DNA virus in European badgers. In addition, sequences with homology to viruses from the families Paramyxo- and Picornaviridae were detected.

van den Brand, Judith M. A.; van Leeuwen, Marije; Schapendonk, Claudia M.; Simon, James H.; Haagmans, Bart L.; Osterhaus, Albert D. M. E.

2012-01-01

369

Simple Rules for Efficient Assembly Predict the Layout of a Packaged Viral RNA  

Microsoft Academic Search

Single-stranded RNA (ssRNA) viruses, which include major human pathogens, package their genomes as they assemble their capsids. We show here that the organization of the viral genomes within the capsids provides intriguing insights into the highly cooperative nature of the assembly process. A recent cryo-electron microscopy structure of bacteriophage MS2, determined with only 5-fold symmetry averaging, has revealed the asymmetric

E. C. Dykeman; N. E. Grayson; K. Toropova; N. A. Ranson; P. G. Stockley; R. Twarock

2011-01-01

370

The contribution of molecular epidemiology to the understanding and control of viral diseases of salmonid aquaculture  

Microsoft Academic Search

Molecular epidemiology is a science which utilizes molecular biology to define the distribution of disease in a population\\u000a (descriptive epidemiology) and relies heavily on integration of traditional (or analytical) epidemiological approaches to\\u000a identify the etiological determinants of this distribution. The study of viral pathogens of aquaculture has provided many\\u000a exciting opportunities to apply such tools. This review considers the extent

Michael Snow

2011-01-01

371

Picornavirus non-structural proteins as targets for new anti-virals with broad activity  

Microsoft Academic Search

Picornaviridae is one of the largest viral families and is composed of 14 genera, six of which include human pathogens. The best known picornaviruses are enteroviruses (including polio, PV, and rhinoviruses), foot-and-mouth disease virus (FMDV), and hepatitis A virus (HAV). Although infections often are mild, certain strains may cause pandemic outbreaks accompanied with meningitis and\\/or paralysis. Vaccines are available for

Heléne Norder; Armando M. De Palma; Barbara Selisko; Lionel Costenaro; Nicolas Papageorgiou; Carme Arnan; Bruno Coutard; Violaine Lantez; Xavier De Lamballerie; Cécile Baronti; Maria Solà; Jinzhi Tan; Johan Neyts; Bruno Canard; Miquel Coll; Alexander E. Gorbalenya; Rolf Hilgenfeld

2011-01-01

372

Identification of viral genes essential for replication of murine -herpesvirus 68 using signature-tagged mutagenesis  

Microsoft Academic Search

-Herpesviruses, Epstein-Barr virus, and Kaposi's sarcoma-associated herpesvirus are important human pathogens, because they are involved in tumor development. Murine -herpesvirus-68 (MHV-68 or HV-68) has emerged as a small animal model system for the study of -herpesvirus pathogenesis and host-virus interactions. To identify the genes required for viral replication in vitro and in vivo, we generated 1,152 mutants using signature-tagged transposon

Moon Jung Song; Seungmin Hwang; Wendy H. Wong; Ting-Ting Wu; Sangmi Lee; Hsiang-I. Liao; Ren Sun

2005-01-01

373

Universal extraction method for gastrointestinal pathogens.  

PubMed

A universal stool extraction method for recovery of nucleic acids (NAs) from gastrointestinal pathogens was developed to support rapid diagnostics for the London 2012 Olympics. The method involved mechanical disruption (bead beating) of the stools, followed by automated extraction and detection using real-time PCR. This method had been used extensively in the Second Infectious Intestinal Disease Study (IID2) for the isolation of NA from bacteria and parasites (and was effective for the robust recovery of Cryptosporidium spp.) but had not been used for enteric viruses. To ensure this method was universally suitable, panels of samples known to contain target bacteria, viruses or parasites were processed in triplicate using the pre-treatment method routinely used for each target and the new extraction method (bead beating). The extracts were tested using real-time PCR and the cycle threshold values were compared. The results from this study showed that bead beating improved yields for the bacterial and parasitic targets and was suitable for the viral targets. The implementation of this universal method should confer cost- and time-saving benefits and streamline the processes required for the characterization of an array of pathogens from faecal samples. PMID:23831766

Halstead, Fenella D; Lee, Adele V; Couto-Parada, Xose; Polley, Spencer D; Ling, Clare; Jenkins, Claire; Chalmers, Rachel M; Elwin, Kristin; Gray, Jim J; Iturriza-Gómara, Miren; Wain, John; Clark, Duncan A; Bolton, Frederick J; Manuel, Rohini J

2013-07-05

374

Rapid identification of emerging pathogens: coronavirus.  

PubMed

We describe a new approach for infectious disease surveillance that facilitates rapid identification of known and emerging pathogens. The process uses broad-range polymerase chain reaction (PCR) to amplify nucleic acid targets from large groupings of organisms, electrospray ionization mass spectrometry for accurate mass measurements of PCR products, and base composition signature analysis to identify organisms in a sample. We demonstrate this principle by using 14 isolates of 9 diverse Coronavirus spp., including the severe acute respiratory syndrome-associated coronavirus (SARS-CoV). We show that this method could identify and distinguish between SARS and other known CoV, including the human CoV 229E and OC43, individually and in a mixture of all 3 human viruses. The sensitivity of detection, measured by using titered SARS-CoV spiked into human serum, was approximate, equals1 PFU/mL. This approach, applicable to the surveillance of bacterial, viral, fungal, or protozoal pathogens, is capable of automated analysis of >900 PCR reactions per day. PMID:15757550

Sampath, Rangarajan; Hofstadler, Steven A; Blyn, Lawrence B; Eshoo, Mark W; Hall, Thomas A; Massire, Christian; Levene, Harold M; Hannis, James C; Harrell, Patina M; Neuman, Benjamin; Buchmeier, Michael J; Jiang, Yun; Ranken, Raymond; Drader, Jared J; Samant, Vivek; Griffey, Richard H; McNeil, John A; Crooke, Stanley T; Ecker, David J

2005-03-01

375

Chitosan against cutaneous pathogens  

PubMed Central

Propionibacterium acnes and Staphylococcus aureus are cutaneous pathogens that have become increasingly resistant to antibiotics. We sought to determine if chitosan, a polymer of deacetylated chitin, could be used as a potential treatment against these bacteria. We found that higher molecular weight chitosan had superior antimicrobial properties compared to lower molecular weights, and that this activity occurred in a pH dependent manner. Electron and fluorescence microscopy revealed that chitosan forms aggregates and binds to the surface of bacteria, causing shrinkage of the bacterial membrane from the cell wall. Of special relevance, clinical isolates of P. acnes were vulnerable to chitosan, which could be combined with benzoyl peroxide for additive antibacterial effect. Chitosan also demonstrated significantly less cytotoxicity to monocytes than benzoyl peroxide. Overall, chitosan demonstrates many promising qualities for treatment of cutaneous pathogens.

2013-01-01

376

Genomic analysis of uncultured marine viral communities  

PubMed Central

Viruses are the most common biological entities in the oceans by an order of magnitude. However, very little is known about their diversity. Here we report a genomic analysis of two uncultured marine viral communities. Over 65% of the sequences were not significantly similar to previously reported sequences, suggesting that much of the diversity is previously uncharacterized. The most common significant hits among the known sequences were to viruses. The viral hits included sequences from all of the major families of dsDNA tailed phages, as well as some algal viruses. Several independent mathematical models based on the observed number of contigs predicted that the most abundant viral genome comprised 2–3% of the total population in both communities, which was estimated to contain between 374 and 7,114 viral types. Overall, diversity of the viral communities was extremely high. The results also showed that it would be possible to sequence the entire genome of an uncultured marine viral community.

Breitbart, Mya; Salamon, Peter; Andresen, Bjarne; Mahaffy, Joseph M.; Segall, Anca M.; Mead, David; Azam, Farooq; Rohwer, Forest

2002-01-01

377

Characterization of the Viral Microbiome in Patients with Severe Lower Respiratory Tract Infections, Using Metagenomic Sequencing  

PubMed Central

The human respiratory tract is heavily exposed to microorganisms. Viral respiratory tract pathogens, like RSV, influenza and rhinoviruses cause major morbidity and mortality from respiratory tract disease. Furthermore, as viruses have limited means of transmission, viruses that cause pathogenicity in other tissues may be transmitted through the respiratory tract. It is therefore important to chart the human virome in this compartment. We have studied nasopharyngeal aspirate samples submitted to the Karolinska University Laboratory, Stockholm, Sweden from March 2004 to May 2005 for diagnosis of respiratory tract infections. We have used a metagenomic sequencing strategy to characterize viruses, as this provides the most unbiased view of the samples. Virus enrichment followed by 454 sequencing resulted in totally 703,790 reads and 110,931 of these were found to be of viral origin by using an automated classification pipeline. The snapshot of the respiratory tract virome of these 210 patients revealed 39 species and many more strains of viruses. Most of the viral sequences were classified into one of three major families; Paramyxoviridae, Picornaviridae or Orthomyxoviridae. The study also identified one novel type of Rhinovirus C, and identified a number of previously undescribed viral genetic fragments of unknown origin.

Lysholm, Fredrik; Wetterbom, Anna; Lindau, Cecilia; Darban, Hamid; Bjerkner, Annelie; Fahlander, Kristina; Lindberg, A. Michael; Persson, Bengt; Allander, Tobias; Andersson, Bjorn

2012-01-01

378

P53-Mediated Rapid Induction of Apoptosis Conveys Resistance to Viral Infection in Drosophila melanogaster  

PubMed Central

Arthropod-borne pathogens account for millions of deaths each year. Understanding the genetic mechanisms controlling vector susceptibility to pathogens has profound implications for developing novel strategies for controlling insect-transmitted infectious diseases. The fact that many viruses carry genes that have anti-apoptotic activity has long led to the hypothesis that induction of apoptosis could be a fundamental innate immune response. However, the cellular mechanisms mediating the induction of apoptosis following viral infection remained enigmatic, which has prevented experimental verification of the functional significance of apoptosis in limiting viral infection in insects. In addition, studies with cultured insect cells have shown that there is sometimes a lack of apoptosis, or the pro-apoptotic response happens relatively late, thus casting doubt on the functional significance of apoptosis as an innate immunity. Using in vivo mosquito models and the native route of infection, we found that there is a rapid induction of reaper-like pro-apoptotic genes within a few hours following exposure to DNA or RNA viruses. Recapitulating a similar response in Drosophila, we found that this rapid induction of apoptosis requires the function of P53 and is mediated by a stress–responsive regulatory region upstream of reaper. More importantly, we showed that the rapid induction of apoptosis is responsible for preventing the expression of viral genes and blocking the infection. Genetic changes influencing this rapid induction of reaper-like pro-apoptotic genes led to significant differences in susceptibility to viral infection.

Liu, Bo; Behura, Susanta K.; Clem, Rollie J.; Schneemann, Anette; Becnel, James; Severson, David W.; Zhou, Lei

2013-01-01

379

Pathogenicity Islands in Bacterial Pathogenesis  

PubMed Central

In this review, we focus on a group of mobile genetic elements designated pathogenicity islands (PAI). These elements play a pivotal role in the virulence of bacterial pathogens of humans and are also essential for virulence in pathogens of animals and plants. Characteristic molecular features of PAI of important human pathogens and their role in pathogenesis are described. The availability of a large number of genome sequences of pathogenic bacteria and their benign relatives currently offers a unique opportunity for the identification of novel pathogen-specific genomic islands. However, this knowledge has to be complemented by improved model systems for the analysis of virulence functions of bacterial pathogens. PAI apparently have been acquired during the speciation of pathogens from their nonpathogenic or environmental ancestors. The acquisition of PAI not only is an ancient evolutionary event that led to the appearance of bacterial pathogens on a timescale of millions of years but also may represent a mechanism that contributes to the appearance of new pathogens within a human life span. The acquisition of knowledge about PAI, their structure, their mobility, and the pathogenicity factors they encode not only is helpful in gaining a better understanding of bacterial evolution and interactions of pathogens with eukaryotic host cells but also may have important practical implications such as providing delivery systems for vaccination, tools for cell biology, and tools for the development of new strategies for therapy of bacterial infections.

Schmidt, Herbert; Hensel, Michael

2004-01-01

380

Toll-like receptor 3 in viral pathogenesis: friend or foe?  

PubMed

Viral infections frequently induce acute and chronic inflammatory diseases, yet the contribution of the innate immune response to a detrimental host response remains poorly understood. In virus-infected cells, double-stranded RNA (dsRNA) is generated as an intermediate during viral replication. Cell necrosis (and the release of endogenous dsRNA) is a common event during both sterile and infectious inflammatory processes. The discovery of Toll-like receptor 3 (TLR3) as an interferon-inducing dsRNA sensor led to the assumption that TLR3 was the master sentinel against viral infections. This simplistic view has been challenged by the discovery of at least three members of the DExd/H-box helicase cytosolic sensors of dsRNA that share with TLR3 the Toll-interleukin-1 receptor (TIR) -adapter molecule TIR domain-containing adaptor protein interferon-? (TRIF) for downstream type I interferon signalling. Data are conflicting on the role of TLR3 in protective immunity against viruses in the mouse model. Varying susceptibility to infection and disease outcomes have been reported in TLR3-immunodeficient mice. Surprisingly, the susceptibility to develop herpes simplex virus-1 encephalitis in humans with inborn defects of the TLR3 pathway varies, and TLR3-deficient humans do not show increased susceptibility to other viral infections. Therefore, a current challenge is to understand the protective versus pathogenic contribution of TLR3 in viral infections. We review recent advances in the identification of TLR3-signalling pathways, endogenous and virus-induced negative regulators of the TLR3 cascade, and discuss the protective versus pathogenic role of TLR3 in viral pathogenesis. PMID:23909285

Perales-Linares, Renzo; Navas-Martin, Sonia

2013-10-01

381

[Workshop on Molecular Epidemiology of Viral Diseases].  

PubMed

A workshop on viral epidemiology was held on September 29, 1995 at the Medical School of the Universidad Nacional Autónoma de Mexico. The aim of this workshop was to promote interaction among scientists working in viral epidemiology. Eighteen scientists from ten institutions presented their experiences and work. General aspects of the epidemiology of meaningful viral diseases in the country were discussed, and lectures presented on the rota, polio, respiratory syncytial, dengue, papiloma, rabies, VIH and hepatitis viruses. PMID:9504103

Gómez, B; Cabrera, L; Arias, C F

1997-01-01

382

Viral security proteins: counteracting host defences  

Microsoft Academic Search

Interactions with host defences are key aspects of viral infection. Various viral proteins perform counter-defensive functions, but a distinct class, called security proteins, is dedicated specifically to counteracting host defences. Here, the properties of the picornavirus security proteins L and 2A are discussed. These proteins have well-defined positions in the viral polyprotein, flanking the capsid precursor, but they are structurally

Anatoly P. Gmyl; Vadim I. Agol

2010-01-01

383

Quantum dot encapsulation in viral capsids.  

PubMed

Incorporation of CdSe/ZnS semiconductor quantum dots (QDs) into viral particles provides a new paradigm for the design of intracellular microscopic probes and vectors. Several strategies for the incorporation of QDs into viral capsids were explored; those functionalized with poly(ethylene glycol) (PEG) can be self-assembled into viral particles with minimal release of photoreaction products and enhanced stability against prolonged irradiation. PMID:16968014

Dixit, Suraj K; Goicochea, Nancy L; Daniel, Marie-Christine; Murali, Ayaluru; Bronstein, Lyudmila; De, Mrinmoy; Stein, Barry; Rotello, Vincent M; Kao, C Cheng; Dragnea, Bogdan

2006-09-01

384

Viral Advertising: Definitional Review and Synthesis  

Microsoft Academic Search

The objectives of this article are threefold. First, it provides an overview of the past published social media research focusing on different aspects of the viral communication, variously termed “electronic word-of-mouth,” “word-of-mouse,” “viral marketing,” and “buzz.” Second, it clarifies and analyzes the concept of viral advertising in social media. Third, it provides a definition to reduce the prevailing ambiguities in

Maria Petrescu; Pradeep Korgaonkar

2011-01-01

385

Modelling the within-host growth of viral infections in insects.  

PubMed

Insects are infected by a variety of pathogens, including bacteria, fungi and viruses, which have been studied largely for their potential as biocontrol agents, but are also important in insect conservation (biodiversity) and as model systems for other diseases. Whilst the dynamics of host-pathogen interactions are well-studied at the population level, less attention has been paid to the critical within-host infection stage. Here, the reproductive rate of the pathogen is largely determined by how it exploits the host; the resources supplied by the host in terms of size and condition; competition with other pathogens; and the speed with which it kills the host (death being an inevitable outcome for obligate-killing pathogens). In this paper we aim to build upon recent developments in the literature by conducting single infection bioassays to obtain data on growth and fitness parameters for phenotypically different and similar strains of nucleopolyhedroviruses in the Lepdipoteran host Spodoptera exigua. Using these data, a simple mechanistic mathematical model (a coupled system of differential equations) is derived, fitted and parameter sensitivity predictions are made which support empirical findings. We unexpectedly found that initial growth of virus within the host occurs at a double-exponential rate, which contrasts with empirical findings for vertebrate host-pathogen systems. Moreover, these infection rates differ between strains, which has significant implications for the evolution of virulence and strain coexistence in the field, which are still relative unknowns. Furthermore, our model predicts that, counter to intuition, increased viral doses may lead to a decrease in viral yield, which is supported by other studies. We explain the mechanism for this phenomenon and discuss its implications for insect host-pathogen ecology. PMID:22877574

White, S M; Burden, J P; Maini, P K; Hails, R S

2012-07-31

386

Relationships between proteasomes and viral gene products.  

PubMed

The interrelationships between proteasomes and viral gene products are very complex. 20S proteasomes associate with a number of viral mRNAs which are cleaved by proteasome's associated endonuclease activity. In addition proteasome's endopeptidase activities are involved in the presentation of viral antigens. Viral proteins of different origin associate with the 20S and 26S complexes and interfere with their enzymatic activities. A major part of this review deals with the interactions between 20S proteasomes and the gene products of the human immunodeficiency virus (HIV) which has been studied in detail by our group. PMID:10363656

Jarrousse, A S; Gautier, K; Apcher, S; Badaoui, S; Boissonnet, G; Dadet, M H; Henry, L; Bureau, J P; Schmid, H P; Petit, F

1999-04-01

387

Hantaviruses in the Americas and Their Role as Emerging Pathogens  

PubMed Central

The continued emergence and re-emergence of pathogens represent an ongoing, sometimes major, threat to populations. Hantaviruses (family Bunyaviridae) and their associated human diseases were considered to be confined to Eurasia, but the occurrence of an outbreak in 1993–94 in the southwestern United States led to a great increase in their study among virologists worldwide. Well over 40 hantaviral genotypes have been described, the large majority since 1993, and nearly half of them pathogenic for humans. Hantaviruses cause persistent infections in their reservoir hosts, and in the Americas, human disease is manifest as a cardiopulmonary compromise, hantavirus cardiopulmonary syndrome (HCPS), with case-fatality ratios, for the most common viral serotypes, between 30% and 40%. Habitat disturbance and larger-scale ecological disturbances, perhaps including climate change, are among the factors that may have increased the human caseload of HCPS between 1993 and the present. We consider here the features that influence the structure of host population dynamics that may lead to viral outbreaks, as well as the macromolecular determinants of hantaviruses that have been regarded as having potential contribution to pathogenicity.

Hjelle, Brian; Torres-Perez, Fernando

2010-01-01

388

Chinese highly pathogenic porcine reproductive and respiratory syndrome virus exhibits more extensive tissue tropism for pigs  

PubMed Central

Background The highly pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) emerging in China exhibits high fatality to pigs. However, the mechanism related to the increased pathogenicity of the virus remains unclear. In the present study, the differences in tissue tropism between the highly pathogenic PRRSV strain (JXwn06) and the low pathogenic PRRSV strain (HB-1/3.9) were investigated using PRRSV-specific immunohistochemistry (IHC) staining to provide evidence for elucidating possible mechanism of the pathogenicity of Chinese highly pathogenic PRRSV. Findings IHC examination showed that PRRSV antigen in the tissues including spleen, tonsil, thymus, kidney, cerebellum, stomach, small intestine, large intestine, turbinal bone and laryngeal cartilage was positive in more pigs inoculated with JXwn06 than HB-1/3.9, and the tissues including trachea, esophagus, liver, mandibular gland and thyroid gland were positive for viral antigen in the pigs inoculated with JXwn06, but not in the pigs inoculated with HB-1/3.9. Meanwhile, we observed that epithelium in tissues including interlobular bile duct in liver, distal renal tubule of kidney, esophageal gland and tracheal gland were positive for viral antigen only in JXwn06-inoculated pigs, and epithelium of gastric mucosa and fundic gland, and intestinal gland were positive for viral antigen in both JXwn06- and HB-1/3.9-inoculated pigs, using monoclonal antibodies to N and Nsp2 proteins. Conclusions Taken together, these findings indicate that the highly pathogenic PRRSV JXwn06 displays an expanded tissue tropism in vivo, suggesting this may contribute to its high pathogenicity to pigs.

2012-01-01

389

Potential use of microarray technology for rapid identification of central nervous system pathogens.  

PubMed

Outbreaks of central nervous system (CNS) diseases result in significant productivity and financial losses, threatening peace and wartime readiness capabilities. To meet this threat, rapid clinical diagnostic tools for detecting and identifying CNS pathogens are needed. Current tools and techniques cannot efficiently deal with CNS pathogen diversity; they cannot provide real-time identification of pathogen serogroups and strains, and they require days, sometimes weeks, for examination of tissue culture. Rapid and precise CNS pathogen diagnostics are needed to provide the opportunity for tailored therapeutic regimens and focused preventive efforts to decrease morbidity and mortality. Such diagnostics are available through genetic and genomic technologies, which have the potential for reducing the time required in serogroup or strain identification from 500+ hours for some viral cultures to less than 3 hours for all pathogens. In the near future, microarray diagnostics and future derivations of these technologies will change the paradigm used for outbreak investigations and will improve health care for all. PMID:15379069

Hanson, Eric H; Niemeyer, Debra M; Folio, Les; Agan, Brian K; Rowley, Robb K

2004-08-01

390

Development of Vaccinia reporter viruses for rapid, high content analysis of viral function at all stages of gene expression.  

PubMed

Vaccinia virus is the prototypical orthopoxvirus of Poxviridae, a family of viruses that includes the human pathogens Variola (smallpox) and Monkeypox. Core viral functions are conserved among orthopoxviruses, and consequently Vaccinia is routinely used to study poxvirus biology and screen for novel antiviral compounds. Here we describe the development of a series of fluorescent protein-based reporter Vaccinia viruses that provide unprecedented resolution for tracking viral function. The reporter viruses are divided into two sets: (1) single reporter viruses that utilize temporally regulated early, intermediate, or late viral promoters; and (2) multi-reporter viruses that utilize multiple temporally regulated promoters. Promoter and reporter combinations were chosen that yielded high signal-to-background for stage-specific viral outputs. We provide examples for how these viruses can be used in the rapid and accurate monitoring of Vaccinia function and drug action. PMID:21569797

Dower, Ken; Rubins, Kathleen H; Hensley, Lisa E; Connor, John H

2011-05-05

391

[Glutathione system in erythrocytes and plasma in viral hepatitis].  

PubMed

In all 5 acute (AVHs) and chronic viral hepatites (CVHs) there was the increase of erythrocyte activities of glutathione peroxidase (GPx) and glutathione reductase (GR), and the decrerase in GSH concentration. In blood plasma there was accumulation of GPx, glutathione S-transferase (GST) and y-glutamyl transferase (gammaGT). GSH and GR increased in plasma only in AVHs. In CVH C erythrocyte GST increased. Evidently changes in the erythrocyte glutathione system are reactions to oxidative stress and in blood plasma they are consequences of inflammation and hepatocyte cytolysis. Changes were more pronounced in middle-heavy course than in the heavy one. These changes have pathogenic importance and can be used in addition to complex diagnostics. They are significantly differed from changes in chronic gall-bladder diseases. Necessity of separate investigation of glutathione system in erythrocytes and blood plasma but not in whole blood is argued. PMID:17436689

Kulinski?, V I; Leonova, Z A; Kolesnichenko, L S; Malov, I V; Danilov, Iu A

392

Bacterial pathogen evolution: breaking news.  

PubMed

The immense social and economic impact of bacterial pathogens, from drug-resistant infections in hospitals to the devastation of agricultural resources, has resulted in major investment to understand the causes and consequences of pathogen evolution. Recent genome sequencing projects have provided insight into the evolution of bacterial genome structures; revealing the impact of mobile DNA on genome restructuring and pathogenicity. Sequencing of multiple genomes of related strains has enabled the delineation of pathogen evolution and facilitated the tracking of bacterial pathogens globally. Other recent theoretical and empirical studies have shown that pathogen evolution is significantly influenced by ecological factors, such as the distribution of hosts within the environment and the effects of co-infection. We suggest that the time is ripe for experimentalists to use genomics in conjunction with evolutionary ecology experiments to further understanding of how bacterial pathogens evolve. PMID:21047697

Jackson, Robert W; Johnson, Louise J; Clarke, Simon R; Arnold, Dawn L

2010-11-01

393

Efficient cochlear gene transfection in guinea-pigs with adeno-associated viral vectors by partial digestion of round window membrane  

Microsoft Academic Search

The auditory portion of the inner ear, the cochlea, is an ideal organ for local gene transfection owing to its relative isolation. Various carriers have been tested for cochlear gene transfection. To date, viral vectors appear to have much higher transfection efficacy than non-viral mechanisms. Among these vectors, recombinant adeno-associated virus (rAAV) vectors have several advantages such as being non-pathogenic

H Wang; R Murphy; D Taaffe; S Yin; L Xia; W W Hauswirth; M Bance; G S Robertson; J Wang

2012-01-01

394

Activation of TBK1 and IKK  Kinases by Vesicular Stomatitis Virus Infection and the Role of Viral Ribonucleoprotein in the Development of Interferon Antiviral Immunity  

Microsoft Academic Search

Mounting an immune response to a viral pathogen involves the initial recognition of viral antigens through Toll-like receptor-dependent and -independent pathways and the subsequent triggering of signal transduction cascades. Among the many cellular kinases stimulated in response to virus infection, the noncanonical IKK-related kinases TBK1 and IKK have been shown to phosphorylate and activate interferon regulatory factor 3 (IRF-3) and

Benjamin R. tenOever; Sonia Sharma; Wen Zou; Qiang Sun; Nathalie Grandvaux; Ilkka Julkunen; Hiroaki Hemmi; M. Yamamoto; Shizuo Akira; Wen-Chen Yeh; Rongtuan Lin; John Hiscott

2004-01-01

395

Viral Ancestors of Antiviral Systems  

PubMed Central

All life must survive their corresponding viruses. Thus antiviral systems are essential in all living organisms. Remnants of virus derived information are also found in all life forms but have historically been considered mostly as junk DNA. However, such virus derived information can strongly affect host susceptibility to viruses. In this review, I evaluate the role viruses have had in the origin and evolution of host antiviral systems. From Archaea through bacteria and from simple to complex eukaryotes I trace the viral components that became essential elements of antiviral immunity. I conclude with a reexamination of the ‘Big Bang’ theory for the emergence of the adaptive immune system in vertebrates by horizontal transfer and note how viruses could have and did provide crucial and coordinated features.

Villarreal, Luis P.

2011-01-01

396

Viral ancestors of antiviral systems.  

PubMed

All life must survive their corresponding viruses. Thus antiviral systems are essential in all living organisms. Remnants of virus derived information are also found in all life forms but have historically been considered mostly as junk DNA. However, such virus derived information can strongly affect host susceptibility to viruses. In this review, I evaluate the role viruses have had in the origin and evolution of host antiviral systems. From Archaea through bacteria and from simple to complex eukaryotes I trace the viral components that became essential elements of antiviral immunity. I conclude with a reexamination of the 'Big Bang' theory for the emergence of the adaptive immune system in vertebrates by horizontal transfer and note how viruses could have and did provide crucial and coordinated features. PMID:22069523

Villarreal, Luis P

2011-10-20

397

Viral bronchiolitis for the clinician.  

PubMed

Viral bronchiolitis is common, and about 98-99% of infants are managed in the home. Because about 95% of infants < 2 years old are infected with respiratory syncytial virus, however, bronchiolitis is the commonest reason for admission to hospital in the first 6 months of life. It is usually a self-limiting condition lasting around a week in previously well children. About 1% of infants are admitted to hospital, and about 10% of hospitalised infants will require admission to the intensive care unit. Respiratory syncytial virus is isolated from about 70% of infants hospitalised with bronchiolitis. The emphasis of hospital treatment is to ensure adequate hydration and oxygenation. Other than supplemental oxygen, little in the way of pharmacological treatment has been demonstrated to alter the course of the illness or the risk of wheezing in the months following bronchiolitis. PMID:20500436

Fitzgerald, Dominic A

2011-04-01

398

Host-Pathogen Interactions  

PubMed Central

A polysaccharide from the fungal pathogen Colletotrichum lindemuthianum causes browning and phytoalexin production when applied to the cut surfaces of bean (Phaseolus vulgaris) cotyledons and hypocotyls. The application of an amount of polysaccharide equivalent to less than 100 ng of glucose will elicit this response in the bean tissues. The polysaccharide has been isolated both from culture filtrates and from the mycelial walls of the fungus. Purification of the polysaccharide involved anion and cation exchange chromatography and gel filtration. The polysaccharide has an apparent molecular weight between 1,000,000 and 5,000,000 daltons, and consists predominantly of 3- and 4-linked glucosyl residues.

Anderson-Prouty, Anne J.; Albersheim, Peter

1975-01-01

399

Building a viral capsid in the presence of genomic RNA  

NASA Astrophysics Data System (ADS)

Virus capsid assembly has traditionally been considered as a process that can be described primarily via self-assembly of the capsid proteins, neglecting interactions with other viral or cellular components. Our recent work on several ssRNA viruses, a major class of viral pathogens containing important human, animal, and plant viruses, has shown that this protein-centric view is too simplistic. Capsid assembly for these viruses relies strongly on a number of cooperative roles played by the genomic RNA. This realization requires a new theoretical framework for the modeling and prediction of the assembly behavior of these viruses. In a seminal paper Zlotnick [J. Mol. Biol.0022-283610.1006/jmbi.1994.1473 241, 59 (1994)] laid the foundations for the modeling of capsid assembly as a protein-only self-assembly process, illustrating his approach using the example of a dodecahedral study system. We describe here a generalized framework for modeling assembly that incorporates the regulatory functions provided by cognate protein-nucleic-acid interactions between capsid proteins and segments of the genomic RNA, called packaging signals, into the model. Using the same dodecahedron system we demonstrate, using a Gillespie-type algorithm to deal with the enhanced complexity of the problem instead of a master equation approach, that assembly kinetics and yield strongly depend on the distribution and nature of the packaging signals, highlighting the importance of the crucial roles of the RNA in this process.

Dykeman, Eric C.; Stockley, Peter G.; Twarock, Reidun

2013-02-01

400

Viral piracy: HIV-1 targets dendritic cells for transmission.  

PubMed

Dendritic cells (DCs), the professional antigen presenting cells, are critical for host immunity by inducing specific immune responses against a broad variety of pathogens. Remarkably the human immunodeficiency virus-1 (HIV-1) subverts DC function leading to spread of the virus. At an early phase of HIV-1 transmission, DCs capture HIV-1 at mucosal surfaces and transmit the virus to T cells in secondary lymphoid tissues. Capture of the virus on DCs takes place via C-type lectins of which the dendritic cell-specific intercellular adhesion molecule-3 (ICAM-3) grabbing nonintegrin (DC-SIGN) is the best studied. DC-SIGN-captured HIV-1 particles accumulate in CD81(+) multivesicular bodies (MVBs) in DCs and are subsequently transmitted to CD4+ T cells resulting in infection of T cells. The viral cell-to-cell transmission takes place at the DC-T cell interface termed the infectious synapse. Recent studies demonstrate that direct infection of DCs contributes to the transmission to T cells at a later phase. Moreover, the infected DCs may function as cellular reservoirs for HIV-1. This review discusses the different processes that govern viral piracy of DCs by HIV-1, emphasizing the intracellular routing of the virus from capture on the cell surface to egress in the infectious synapse. PMID:16611055

Lekkerkerker, Annemarie N; van Kooyk, Yvette; Geijtenbeek, Teunis B H

2006-04-01

401

Environmental survey to assess viral contamination of air and surfaces in hospital settings.  

PubMed

The presence of pathogenic viruses in healthcare settings represents a serious risk for both staff and patients. Direct viral detection in the environment poses significant technical problems and the indirect indicators currently in use suffer from serious limitations. The aim of this study was to monitor surfaces and air in hospital settings to reveal the presence of hepatitis C virus, human adenovirus, norovirus, human rotavirus and torque teno virus by nucleic acid assays, in parallel with measurements of total bacterial count and haemoglobin presence. In total, 114 surface and 62 air samples were collected. Bacterial contamination was very low (<1 cfu/cm(2)) on surfaces, whereas the 'medium' detected value in air was 282 cfu/m(3). Overall, 19 (16.7%) surface samples tested positive for viral nucleic acids: one for norovirus, one for human adenovirus and 17 (14.9%) for torque teno virus (TTV). Only this latter virus was directly detected in 10 air samples (16.1%). Haemoglobin was found on two surfaces. No relationship was found between viral, biochemical or bacterial indicators. The data obtained confirm the difficulty of assessing viral contamination using bacterial indicators. The frequent detection of TTV suggests its possible use as an indicator for general viral contamination of the environment. PMID:21277649

Carducci, A; Verani, M; Lombardi, R; Casini, B; Privitera, G

2011-01-31

402

Mobilizing monocytes to cross-present circulating viral antigen in chronic infection  

PubMed Central

Selection of antigens for therapeutic vaccination against chronic viral infections is complicated by pathogen genetic variations. We tested whether antigens present during persistent viral infections could provide a personalized antigenic reservoir for therapeutic T cell expansion in humans. We focused our study on the HBV surface antigen (HBsAg), which is present in microgram quantities in the serum of chronic HBV patients. We demonstrated by quantitative fluorescent microscopy that, out of 6 professional APC populations in the circulation, only CD14 monocytes (MNs) retained an HBsAg depot. Using TCR-redirected CD8+ T cells specific for MHC-I–restricted HBV epitopes, we showed that, despite being constantly exposed to antigen, ex vivo–isolated APCs did not constitutively activate HBV-specific CD8+ T cells. However, differentiation of HBsAg+ CD14 MNs from chronic patients to MN-derived DCs (moDCs) induced cross-presentation of the intracellular reservoir of viral antigen. We exploited this mechanism to cross-present circulating viral antigen and showed that moDCs from chronically infected patients stimulated expansion of autologous HBV-specific T cells. Thus, these data demonstrate that circulating viral antigen produced during chronic infection can serve as a personalized antigenic reservoir to activate virus-specific T cells.

Gehring, Adam J.; Haniffa, Muzlifah; Kennedy, Patrick T.; Ho, Zi Zong; Boni, Carolina; Shin, Amanda; Banu, Nasirah; Chia, Adeline; Lim, Seng Gee; Ferrari, Carlo; Ginhoux, Florent; Bertoletti, Antonio

2013-01-01

403

Illuminating viral infections in the nervous system  

Microsoft Academic Search

Viral infections are a major cause of human disease. Although most viruses replicate in peripheral tissues, some have developed unique strategies to move into the nervous system, where they establish acute or persistent infections. Viral infections in the central nervous system (CNS) can alter homeostasis, induce neurological dysfunction and result in serious, potentially life-threatening inflammatory diseases. This Review focuses on

Silvia S. Kang; Dorian B. McGavern

2011-01-01

404

Crosslinking in viral capsids via tiling theory  

Microsoft Academic Search

A vital part of a virus is its protein shell, called the viral capsid, that encapsulates and hence protects the viral genome. It has been shown in Twarock [2004. A tiling approach to vius capsids assembly explaining a structural puzzle in virology. J. Theor. Biol. 226, 477–482] that the surface structures of viruses with icosahedrally symmetric capsids can be modelled

R. Twarock; R. W. Hendrix

2006-01-01

405

VÍRUS DA DIARRÉIA VIRAL BOVINA (BVDV)  

Microsoft Academic Search

BOVINE VIRAL DIARRHEA VIRUS. Bovine viral diarrhea virus (BVDV) is distributed worldwide among the cattle population and is considered the most important virus of cattle in countries free of foot and mouth disease virus. BVDV infection has been described in Brazil since the late 60s and is currently widespread among Brazilian beef and dairy cattle. The infection has been associated

E. F. Flores

406

Molecular Engineering of Viral Gene Delivery Vehicles  

Microsoft Academic Search

Viruses can be engineered to efficiently deliver exogenous genes, but their natural gene delivery properties often fail to meet human therapeutic needs. Therefore, engineering viral vectors with new properties, including en- hanced targeting abilities and resistance to immune responses, is a growing area of research. This review discusses protein engineering approaches to generate viral vectors with novel gene delivery capabilities.

David V. Schaffer; James T. Koerber; Kwang-il Lim

2008-01-01

407

Viral control of Emiliania huxleyi blooms?  

Microsoft Academic Search

Virus and virus-like particles (VLP) have been observed in all major algal classes. Few host-virus systems of microalgae have until now been brought into culture and extensively studied. For Emiliania huxleyi we have been able to describe viral infection during blooms in mesocosms and in landlocked fjords. Evidence of viral lysis of E. huxleyi during blooms in the North Sea

Gunnar Bratbak; William Wilson; Mikal Heldal

1996-01-01

408

Diagnosis and treatment of viral encephalitis  

Microsoft Academic Search

Acute encephalitis constitutes a medical emergency. In most cases, the presence of focal neurological signs and focal seizures will distinguish encephalitis from encephalopathy. Acute disseminated encephalomyelitis is a non-infective inflammatory encephalitis that may require to be treated with steroids. Acute infective encephalitis is usually viral. Herpes simplex encephalitis (HSE) is the commonest sporadic acute viral encephalitis in the Western world.

A Chaudhuri; P G E Kennedy

2002-01-01

409

Phylogeny and geography predict pathogen community similarity in wild primates and humans  

PubMed Central

In natural systems, host species are often co-infected by multiple pathogen species, and recent work has suggested that many pathogens can infect a wide range of host species. An important question therefore is what determines the host range of a pathogen and the community of pathogens found within a given host species. Using primates as a model, we show that infectious diseases are more often shared between species that are closely related and inhabit the same geographical region. We find that host relatedness is the best overall predictor of whether two host species share the same pathogens. A higher frequency of pathogen host shifts between close relatives or inheritance of pathogens from a common ancestor may explain this result. For viruses, geographical overlap among neighbouring primate hosts is more important in determining host range. We suggest this is because rapid evolution within viral lineages allows host jumps across larger evolutionary distances. We also show that the phylogenetic pattern of pathogen sharing with humans is the same as that between wild primates. For humans, this means we share a higher proportion of pathogens with the great apes, including chimpanzees and gorillas, because these species are our closest relatives.

Davies, T. Jonathan; Pedersen, Amy B

2008-01-01

410

Itchy fish and viral dermatopathies: sampling, diagnosis, and management of common viral diseases.  

PubMed

Viral dermatopathies of fish bear clinical signs similar to those of dermatopathies from other causes. This article offers an overview to approaching dermatologic presentations in fish, with an emphasis on sampling, diagnosis, and management of viral dermatopathies, building on previous publications. It is vital to recognize clinical signs associated with viral dermatopathies because there are currently no treatments available. Avoidance and prevention is the key to controlling viral diseases in fish. Optimizing husbandry practices and providing appropriate quarantine procedures can help prevent viral disease outbreaks in collection and aquaculture stocks. PMID:24018032

Weber, E P Scott

2013-09-01

411

Genomics of epidemic pathogens.  

PubMed

Virulence factors are thought to be responsible for the virulence capacity of pathogenic bacteria. However, epidemic bacteria were recently found to contain significantly fewer 'virulence factors' than non-epidemic species, and some of the most dangerous epidemic bacteria, such as Mycobacteria spp. and Rickettsia spp., have reduced genomes, and contain hundreds of degraded genes. Epidemic bacteria are actually highly specialized species, characterized by allopatric speciation, that, after adapting to their hosts, attempt to maintain a balance between gene gain and gene loss that favours gene loss, finally leading to genome reduction. Recent comparative genomic studies have demonstrated that the specialization of bacteria to eukaryotic cells is associated with massive gene loss. Furthermore, the 12 deadliest epidemic species for humankind have significantly smaller genomes, with fewer open reading frames, than less dangerous species. Epidemic species mostly lose genes related to metabolic activity, the production of energy, cell motility, and transcription. Epidemic bacteria also possess a damaged recombination and repair system and significantly more toxins than closely related non-pathogenic or non-epidemic species, and more toxin-antitoxin modules. Epidemic bacteria are therefore highly specialized species that are adapted to their hosts and characterized by extensive genome reduction. Except for toxins and toxin-antitoxin modules, which have a direct and measurable effect, other 'virulence factors' are factors associated with fitness in experimental models. Epidemic species are defined by a virulent genomic repertoire including both present and absent genes. PMID:22369153

Georgiades, K

2012-03-01

412

Emerging pathogens--the white horse of the apocalypse?  

PubMed

The concept of emerging microbial disease is discussed both in a historical and contemporary perspective. Major factors contributing to emergence of viral, bacterial, rickettsial, and parasitic diseases over the last 25 years are discussed. Forty agents are listed in a table by year of recognition/emergence, mode of transmission, geographical distribution, and symptom complex. Public health prevention and control measures and long-term public health implications are also summarized. Suggestions are offered on how to retrieve appropriate information on newly emerging pathogens and to obtain authoritative and timely information on surveillance data using electronic mail access. PMID:10186609

Malloy, C D; Gallo, R J; Leib, H B; Marr, J S

1995-01-01

413

A Pathogenic Threshold of Virus Load Defined in Simian Immunodeficiency Virus or Simian-Human Immunodeficiency VirusInfected Macaques  

Microsoft Academic Search

To determine if a specific pathogenic threshold of plasma viral RNA could be defined irrespective of virus strain, RNA levels in the plasma of more than 50 infected rhesus macaques (Macaca mulatta) were measured. Animals were inoculated intravenously with either simian immunodeficiency virus (SIV) or simian-human immunodeficiency virus (SHIV) strains of known pathogenic potential (SIV8980, SIVsmm-3, SIVmac32H\\/J5, SIVmac32H\\/1XC, reverse transcriptase-SHIV,

PETER TEN HAAFT; BABS VERSTREPEN; KLAUS UBERLA; BRIGITTE ROSENWIRTH; JONATHAN HEENEY

1998-01-01

414

Higher levels of IL18 circulate during primary infection of monkeys with a pathogenic SHIV than with a nonpathogenic SHIV  

Microsoft Academic Search

We have monitored kinetics of peripheral blood Interleukin (IL)-18 level, viral RNA load, and CD4+ T cell counts in cynomolgus and rhesus macaques following infections of various simian\\/human immunodeficiency viruses (SHIVs) causing differential pathogenicity. Infections of cynomolgus and rhesus macaques with pathogenic SHIVs-C2\\/1 and -89.6PD, respectively, induced high levels of plasma IL-18 (0.1–1 ng\\/ml) and enhanced apoptosis of peripheral blood

Masahiko Kaizu; Yasushi Ami; Tadashi Nakasone; Yuko Sasaki; Yasuyuki Izumi; Hironori Sato; Eiji Takahashi; Koji Sakai; Katsuaki Shinohara; Kenji Nakanishi; Mitsuo Honda

2003-01-01

415

Host envelope glycoprotein processing proteases are indispensable for entry into human cells by seasonal and highly pathogenic avian influenza viruses  

Microsoft Academic Search

Influenza A virus (IAV) is one of the most common infectious pathogens in humans and causes considerable morbidity and mortality. The recent spread of highly-pathogenic avian IAV H5N1 viruses has reinforced the importance of pandemic preparedness. In the pathogenesis of IAV infection, cellular proteases play critical roles in the process of viral entry into cells that subsequently leads to tissue

Hiroshi Kido; Yuushi Okumura; Etsuhisa Takahashi; Siye Wang; Junji Chida; Mihiro Yano

2009-01-01

416

Pathogenic potential of lactobacilli.  

PubMed

Lactobacilli are often considered to be commensal or beneficial participants in human microbial ecology and considerable research is being carried out into the effects of the use of lactobacilli as additives in both human and animal diets. However, lactobacilli also cause some human diseases (e.g. dental caries, rheumatic vascular disease, septicaemia and infective endocarditis (IE)), and have recently been identified as potential emerging pathogens in elderly and immunocompromised patients, particularly those receiving broad spectrum antibiotic therapy. The identification of potential pathogenic traits amongst lactobacilli will therefore facilitate the use of the organisms for probiotic purposes. The ability to aggregate human platelets is considered to be a possible pathogenic trait in the progression of IE. A comparison of bacterial cell surface properties amongst L. rhamnosus strains showed that platelets were aggregated by 5/5 IE strains and 8/16 laboratory strains. For the L. paracasei subsp. paracasei strains the respective numbers were 2/5 and 2/9. However two strains, morphological mutants of a non-aggregating strain, which had been re-isolated after passaging through rats were found to aggregate platelets. No loss of aggregating function occurred on extensive subculturing of IE strains. Aggregation also occurred with 11/14 strains for five other species, namely, Lactobacillus acidophilus, Lactobacillus fermentum, Lactobacillus oris, Lactobacillus plantarum and Lactobacillus salvivarius, with each species being represented indicating that the property is not uncommon in the genus. A comparison of IE and oral isolates of L. rhamnosus and L. paracasei subsp. paracasei and seven other Lactobacillus species, has shown that the binding of both fibronectin and fibrinogen by lactobacilli is greatly increased, up to 50 fold, when the pH is reduced from 7.0 to 5.0. Re-exposing the lactobacilli to a neutral pH environment releases most of the bound proteins, but the amount still remaining bound to the cell is several times more than is bound at neutral pH. Lactobacilli will also bind to the proteins that make up the extracellular matrix of endothelial cells. Lactobacilli bound significantly better to collagen types I and V than to types III and IV (p < 0.01). Further, strains isolated from IE cases, particularly L. rhamnosus strains, bound significantly better to types I and V than did 'normal' strains (p < 0.02). Type V collagen has been demonstrated at the sites of endothelial damage. Thus the binding of lactobacilli, particularly L. rhamnosus to these collagen types may be of importance in the early stages of colonization of the damaged heart valve.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:7703012

Harty, D W; Oakey, H J; Patrikakis, M; Hume, E B; Knox, K W

1994-12-01

417

A genome-to-genome analysis of associations between human genetic variation, HIV-1 sequence diversity, and viral control.  

PubMed

HIV-1 sequence diversity is affected by selection pressures arising from host genomic factors. Using paired human and viral data from 1071 individuals, we ran >3000 genome-wide scans, testing for associations between host DNA polymorphisms, HIV-1 sequence variation and plasma viral load (VL), while considering human and viral population structure. We observed significant human SNP associations to a total of 48 HIV-1 amino acid variants (p<2.4 × 10(-12)). All associated SNPs mapped to the HLA class I region. Clinical relevance of host and pathogen variation was assessed using VL results. We identified two critical advantages to the use of viral variation for identifying host factors: (1) association signals are much stronger for HIV-1 sequence variants than VL, reflecting the 'intermediate phenotype' nature of viral variation; (2) association testing can be run without any clinical data. The proposed genome-to-genome approach highlights sites of genomic conflict and is a strategy generally applicable to studies of host-pathogen interaction. DOI:http://dx.doi.org/10.7554/eLife.01123.001. PMID:24171102

Bartha, István; Carlson, Jonathan M; Brumme, Chanson J; McLaren, Paul J; Brumme, Zabrina L; John, Mina; Haas, David W; Martinez-Picado, Javier; Dalmau, Judith; López-Galíndez, Cecilio; Casado, Concepción; Rauch, Andri; Günthard, Huldrych F; Bernasconi, Enos; Vernazza, Pietro; Klimkait, Thomas; Yerly, Sabine; O'Brien, Stephen J; Listgarten, Jennifer; Pfeifer, Nico; Lippert, Christoph; Fusi, Nicolo; Kutalik, Zoltán; Allen, Todd M; Müller, Viktor; Harrigan, P Richard; Heckerman, David; Telenti, Amalio; Fellay, Jacques

2013-10-29

418

A genome-to-genome analysis of associations between human genetic variation, HIV-1 sequence diversity, and viral control  

PubMed Central

HIV-1 sequence diversity is affected by selection pressures arising from host genomic factors. Using paired human and viral data from 1071 individuals, we ran >3000 genome-wide scans, testing for associations between host DNA polymorphisms, HIV-1 sequence variation and plasma viral load (VL), while considering human and viral population structure. We observed significant human SNP associations to a total of 48 HIV-1 amino acid variants (p<2.4 × 10?12). All associated SNPs mapped to the HLA class I region. Clinical relevance of host and pathogen variation was assessed using VL results. We identified two critical advantages to the use of viral variation for identifying host factors: (1) association signals are much stronger for HIV-1 sequence variants than VL, reflecting the ‘intermediate phenotype’ nature of viral variation; (2) association testing can be run without any clinical data. The proposed genome-to-genome approach highlights sites of genomic conflict and is a strategy generally applicable to studies of host–pathogen interaction. DOI: http://dx.doi.org/10.7554/eLife.01123.001

Bartha, Istvan; Carlson, Jonathan M; Brumme, Chanson J; McLaren, Paul J; Brumme, Zabrina L; John, Mina; Haas, David W; Martinez-Picado, Javier; Dalmau, Judith; Lopez-Galindez, Cecilio; Casado, Concepcion; Rauch, Andri; Gunthard, Huldrych F; Bernasconi, Enos; Vernazza, Pietro; Klimkait, Thomas; Yerly, Sabine; O'Brien, Stephen J; Listgarten, Jennifer; Pfeifer, Nico; Lippert, Christoph; Fusi, Nicolo; Kutalik, Zoltan; Allen, Todd M; Muller, Viktor; Harrigan, P Richard; Heckerman, David; Telenti, Amalio; Fellay, Jacques

2013-01-01

419

Flagella and bacterial pathogenicity.  

PubMed

As locomotive organelles, flagella allow bacteria to move toward favorable environments. A flagellum consists of three parts: the basal structure (rotary motor), the hook (universal joint), and the filament (helical propeller). For ages, flagella have been generally regarded as important virulence factors, mainly because of their motility property. However, flagella are getting recognized to play multiple roles with more functions besides motility and chemotaxis. Recent evidence has pinpointed that the bacterial flagella participate in many additional processes including adhesion, biofilm formation, virulence factor secretion, and modulation of the immune system of eukaryotic cells. This mini-review summarizes data from recent studies that elucidated how flagella, as a virulence factor, contribute to bacterial pathogenicity. PMID:22359233

Duan, Qiangde; Zhou, Mingxu; Zhu, Liqian; Zhu, Guoqiang

2012-02-23

420

Genomic Analysis of Uncultured Marine Viral Communities  

NASA Astrophysics Data System (ADS)

Viruses are the most common biological entities in the oceans by an order of magnitude. Diversity of these viruses undoubtedly plays an important role in controlling bacterial populations and biogeochemical cycles in the marine environment. However, very little is known about the diversity of marine viral communities. Here we report the first genomic analysis of uncultured viral communities from two nearshore marine water samples and one marine sediment sample. In all three marine libraries, over 65% of the sequences were not significantly similar to previously reported sequences, suggesting that much of the diversity is novel. The most common significant hits amongst the known sequences were to viruses. The viral hits included sequences from all the major families of dsDNA tailed phage, as well as some algal viruses. BLAST analysis of the sequence data suggested fundamental differences between the viral communities. Several independent mathematical models based on the observed number of contigs predicted that the most abundant viral genome comprised 2-3% of the total population in the water communities, which were estimated to contain between 374 and 7114 viral types. Diversity of the sediment community was significantly higher. The results also showed that it would be possible to sequence the entire genome of an uncultured marine viral community.

Breitbart, M.; Salamon, P.; Andresen, B.; Mahaffy, J. M.; Segall, A. M.; Mead, D.; Azam, F.; Rohwer, F.

2002-12-01

421

Microsporidia: emerging pathogenic protists.  

PubMed

Microsporidia are eukaryotic spore forming obligate intracellular protozoan parasites first recognized over 100 years ago. These organisms infect all of the major animal groups and are now recognized as opportunistic pathogens of humans. Microsporidian spores are common in the environment and microsporidia pathogenic to humans have been found in water supplies. The genera Nosema, Vittaforma, Brachiola, Pleistophora, Encephalitozoon, Enterocytozoon, Septata (reclassified to Encephalitozoon) and Trachipleistophora have been found in human infections. These organisms have the smallest known eukaryotic genomes. Microsporidian ribosomal RNA sequences have proven useful as diagnostic tools as well as for phylogenetic analysis. Recent phylogenetic analysis suggests that Microsporidia are related to the fungi. These organisms are defined by the presence of a unique invasion organelle consisting of a single polar tube that coils around the interior of the spore. All microsporidia exhibit the same response to stimuli, that is, the polar tube discharges from the anterior pole of the spore in an explosive reaction. If the polar tube is discharged next to a cell, it can pierce the cell and transfer its sporoplasm into the cell. A technique was developed for the purification of polar tube proteins (PTPs) using differential extraction followed by reverse phase HPLC. This method was used to purify the PTPs from Glugea americanus, Encephalitozoon cuniculi, Enc. hellem and Enc. intestinalis. These PTPs demonstrate conserved characteristics such as solubility, hydrophobicity, mass, proline content and immunologic epitopes. The major PTP gene from Enc. cuniculi and Enc. hellem has been cloned and expressed in vitro. The gene sequences support the importance of ER and in the formation of the polar tube as suggested by morphologic studies. Analysis of the cloned proteins also indicates that secondary structural characteristics are conserved. These characteristics are probably important in the function of this protein during the eversion/assembly of the polar tube and in providing elasticity and resiliency for sporoplasm passage. PMID:11230819

Weiss, L M

2001-02-23

422

Identification of Upper Respiratory Tract Pathogens Using Electrochemical Detection on an Oligonucleotide Microarray  

PubMed Central

Bacterial and viral upper respiratory infections (URI) produce highly variable clinical symptoms that cannot be used to identify the etiologic agent. Proper treatment, however, depends on correct identification of the pathogen involved as antibiotics provide little or no benefit with viral infections. Here we describe a rapid and sensitive genotyping assay and microarray for URI identification using standard amplification and hybridization techniques, with electrochemical detection (ECD) on a semiconductor-based oligonucleotide microarray. The assay was developed to detect four bacterial pathogens (Bordetella pertussis, Streptococcus pyogenes, Chlamydia pneumoniae and Mycoplasma pneumoniae) and 9 viral pathogens (adenovirus 4, coronavirus OC43, 229E and HK, influenza A and B, parainfluinza types 1, 2, and 3 and respiratory syncytial virus. This new platform forms the basis for a fully automated diagnostics system that is very flexible and can be customized to suit different or additional pathogens. Multiple probes on a flexible platform allow one to test probes empirically and then select highly reactive probes for further iterative evaluation. Because ECD uses an enzymatic reaction to create electrical signals that can be read directly from the array, there is no need for image analysis or for expensive and delicate optical scanning equipment. We show assay sensitivity and specificity that are excellent for a multiplexed format.

Lodes, Michael J.; Suciu, Dominic; Wilmoth, Jodi L.; Ross, Marty; Munro, Sandra; Dix, Kim; Bernards, Karen; Stover, Axel G.; Quintana, Miguel; Iihoshi, Naomi; Lyon, Wanda J.; Danley, David L.; McShea, Andrew

2007-01-01

423

Selective Serotonin Reuptake Inhibitor Fluoxetine Inhibits Replication of Human Enteroviruses B and D by Targeting Viral Protein 2C  

PubMed Central

Although the genus Enterovirus contains many important human pathogens, there is no licensed drug for either the treatment or the prophylaxis of enterovirus infections. We report that fluoxetine (Prozac)—a selective serotonin reuptake inhibitor—inhibits the replication of human enterovirus B (HEV-B) and HEV-D but does not affect the replication of HEV-A and HEV-C or human rhinovirus A or B. We show that fluoxetine interferes with viral RNA replication, and we identified viral protein 2C as the target of this compound.

Ulferts, Rachel; van der Linden, Lonneke; Thibaut, Hendrik Jan; Lanke, Kjerstin H. W.; Leyssen, Pieter; Coutard, Bruno; De Palma, Armando M.; Canard, Bruno; Neyts, Johan

2013-01-01

424

Selective serotonin reuptake inhibitor fluoxetine inhibits replication of human enteroviruses B and D by targeting viral protein 2C.  

PubMed

Although the genus Enterovirus contains many important human pathogens, there is no licensed drug for either the treatment or the prophylaxis of enterovirus infections. We report that fluoxetine (Prozac)--a selective serotonin reuptake inhibitor--inhibits the replication of human enterovirus B (HEV-B) and HEV-D but does not affect the replication of HEV-A and HEV-C or human rhinovirus A or B. We show that fluoxetine interferes with