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1

Evidence for multiple recent host species shifts among the Ranaviruses (family Iridoviridae).  

PubMed

Members of the genus Ranavirus (family Iridoviridae) have been recognized as major viral pathogens of cold-blooded vertebrates. Ranaviruses have been associated with amphibians, fish, and reptiles. At this time, the relationships between ranavirus species are still unclear. Previous studies suggested that ranaviruses from salamanders are more closely related to ranaviruses from fish than they are to ranaviruses from other amphibians, such as frogs. Therefore, to gain a better understanding of the relationships among ranavirus isolates, the genome of epizootic hematopoietic necrosis virus (EHNV), an Australian fish pathogen, was sequenced. Our findings suggest that the ancestral ranavirus was a fish virus and that several recent host shifts have taken place, with subsequent speciation of viruses in their new hosts. The data suggesting several recent host shifts among ranavirus species increase concern that these pathogens of cold-blooded vertebrates may have the capacity to cross numerous poikilothermic species barriers and the potential to cause devastating disease in their new hosts. PMID:20042506

Jancovich, James K; Bremont, Michel; Touchman, Jeffrey W; Jacobs, Bertram L

2010-03-01

2

Metagenomic identification of viral pathogens.  

PubMed

The target-independent identification of viral pathogens using 'shotgun' metagenomic sequencing is an emerging approach with potentially wide applications in clinical diagnostics, public health monitoring, and viral discovery. In this approach, all viral nucleic acids present in a sample are sequenced in a random, shotgun manner. Pathogens are then identified without the prerequisite of searching for a specific viral pathogen. In this opinion article, I discuss the current state and future research directions for this emerging and disruptive technology. With further technical developments, viral metagenomics has the potential to be deployed as a powerful and widely adopted tool, transforming the way that viral disease is researched, monitored, and treated. PMID:23415279

Bibby, Kyle

2013-05-01

3

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

4

Genome architecture changes and major gene variations of Andrias davidianus ranavirus (ADRV)  

PubMed Central

Ranaviruses are emerging pathogens that have led to global impact and public concern. As a rarely endangered species and the largest amphibian in the world, the Chinese giant salamander, Andrias davidianus, has recently undergone outbreaks of epidemic diseases with high mortality. In this study, we isolated and identified a novel ranavirus from the Chinese giant salamanders that exhibited systemic hemorrhage and swelling syndrome with high death rate in China during May 2011 to August 2012. The isolate, designated Andrias davidianus ranavirus (ADRV), not only could induce cytopathic effects in different fish cell lines and yield high viral titers, but also caused severely hemorrhagic lesions and resulted in 100% mortality in experimental infections of salamanders. The complete genome of ADRV was sequenced and compared with other sequenced amphibian ranaviruses. Gene content and phylogenetic analyses revealed that ADRV should belong to an amphibian subgroup in genus Ranavirus, and is more closely related to frog ranaviruses than to other salamander ranaviruses. Homologous gene comparisons show that ADRV contains 99%, 97%, 94%, 93% and 85% homologues in RGV, FV3, CMTV, TFV and ATV genomes respectively. In addition, several variable major genes, such as duplicate US22 family-like genes, viral eukaryotic translation initiation factor 2 alpha gene and novel 75L gene with both motifs of nuclear localization signal (NLS) and nuclear export signal (NES), were predicted to contribute to pathogen virulence and host susceptibility. These findings confirm the etiologic role of ADRV in epidemic diseases of Chinese giant salamanders, and broaden our understanding of evolutionary emergence of ranaviruses.

2013-01-01

5

Transmission of ranavirus between ectothermic vertebrate hosts.  

PubMed

Transmission is an essential process that contributes to the survival of pathogens. Ranaviruses are known to infect different classes of lower vertebrates including amphibians, fishes and reptiles. Differences in the likelihood of infection among ectothermic vertebrate hosts could explain the successful yearlong persistence of ranaviruses in aquatic environments. The goal of this study was to determine if transmission of a Frog Virus 3 (FV3)-like ranavirus was possible among three species from different ectothermic vertebrate classes: Cope's gray treefrog (Hyla chrysoscelis) larvae, mosquito fish (Gambusia affinis), and red-eared slider (Trachemys scripta elegans). We housed individuals previously exposed to the FV3-like ranavirus with naïve (unexposed) individuals in containers divided by plastic mesh screen to permit water flow between subjects. Our results showed that infected gray treefrog larvae were capable of transmitting ranavirus to naïve larval conspecifics and turtles (60% and 30% infection, respectively), but not to fish. Also, infected turtles and fish transmitted ranavirus to 50% and 10% of the naïve gray treefrog larvae, respectively. Nearly all infected amphibians experienced mortality, whereas infected turtles and fish did not die. Our results demonstrate that ranavirus can be transmitted through water among ectothermic vertebrate classes, which has not been reported previously. Moreover, fish and reptiles might serve as reservoirs for ranavirus given their ability to live with subclinical infections. Subclinical infections of ranavirus in fish and aquatic turtles could contribute to the pathogen's persistence, especially when highly susceptible hosts like amphibians are absent as a result of seasonal fluctuations in relative abundance. PMID:24667325

Brenes, Roberto; Gray, Matthew J; Waltzek, Thomas B; Wilkes, Rebecca P; Miller, Debra L

2014-01-01

6

Virion-associated viral proteins of a Chinese giant salamander (Andrias davidianus) iridovirus (genus Ranavirus) and functional study of the major capsid protein (MCP).  

PubMed

Chinese giant salamander iridovirus (CGSIV) is the emerging causative agent to farmed Chinese giant salamanders in nationwide China. CGSIV is a member of the common midwife toad ranavirus (CMTV) subset of the amphibian-like ranavirus (ALRV) in the genus Ranavirus of Iridoviridae family. However, viral protein information on ALRV is lacking. In this first proteomic analysis of ALRV, 40 CGSIV viral proteins were detected from purified virus particles by liquid chromatography-tandem mass spectrometry analysis. The transcription products of all 40 identified virion proteins were confirmed by reverse transcription polymerase chain reaction analysis. Temporal expression pattern analysis combined with drug inhibition assay indicated that 37 transcripts of the 40 virion protein genes could be classified into three temporal kinetic classes, namely, 5 immediate early, 12 delayed early, and 20 late genes. The presence of major capsid proteins (MCP, ORF019L) and a proliferating cell nuclear antigen (ORF025L) was further confirmed by Western blot analysis. The functions of MCP were also determined by small interfering RNA (siRNA)-based knockdown assay and anti-recombinant MCP serum-based neutralization testing. At low dosages of CGSIV, siRNA-based knockdown of the MCP gene effectively inhibited CGSIV replication in fathead minnow cells. The antiviral effect observed in the anti-MCP serum-based neutralization test confirms the crucial function of the MCP gene in CGSIV replication. Taken together, detailed information on the virion-associated viral proteins of ALRV is presented for the first time. Our results also provide evidence that MCP is essential for CGSIV replication in vitro. PMID:24906872

Li, Wei; Zhang, Xin; Weng, Shaoping; Zhao, Gaoxiang; He, Jianguo; Dong, Chuanfu

2014-08-01

7

Viral encephalitis: familiar infections and emerging pathogens.  

PubMed

Significant advances have been made in our understanding of the natural history and pathogenesis of viral encephalitides. The development of PCR has greatly increased our ability to diagnose viral infections of the central nervous system, particularly for herpes and enteroviral infections. Advancing knowledge has led to the recognition that some encephalitides can be reliably prevented by vaccination (eg, Japanese encephalitis and rabies). For other pathogens such as the arboviruses, the focus has been on prevention by vector control. Finally, effective therapy has been established for a very limited number of viral infections (eg, acyclovir for herpes simplex encephalitis). Other potentially useful treatments, such as pleconaril for enteroviral meningoencephalitis are under clinical evaluation. We review current understanding of viral encephalitides with particular reference to emerging viral infections and the availability of existing treatment regimens. PMID:11853816

Whitley, Richard J; Gnann, John W

2002-02-01

8

Shrimp molecular responses to viral pathogens.  

PubMed

From almost negligible amounts in 1970, the quantity of cultivated shrimp (~3 million metric tons in 2007) has risen to approach that of the capture fishery and it constitutes a vital source of export income for many countries. Despite this success, viral diseases along the way have caused billions of dollars of losses for shrimp farmers. Desire to reduce the losses to white spot syndrome virus in particular, has stimulated much research since 2000 on the shrimp response to viral pathogens at the molecular level. The objective of the work is to develop novel, practical methods for improved disease control. This review covers the background and limitations of the current work, baseline studies and studies on humoral responses, on binding between shrimp and viral structural proteins and on intracellular responses. It also includes discussion of several important phenomena (i.e., the quasi immune response, viral co-infections, viral sequences in the shrimp genome and persistent viral infections) for which little or no molecular information is currently available, but is much needed. PMID:20393775

Flegel, T W; Sritunyalucksana, Kallaya

2011-08-01

9

Electrochemical aptasensors for microbial and viral pathogens.  

PubMed

Aptamers are DNA and RNA oligonucleotides that can bind to a variety of nonnucleic acid targets with high affinity and specificity. Pathogen detection is a promising area in aptamer research. One of its major advantages is the ability of the aptamers to target and specifically differentiate microbial and viral strains without previous knowledge of the membrane-associated antigenic determinants or molecular biomarkers present in that particular microorganism. Electrochemical sensors emerged as a promising field in the area of aptamer research and pathogen detection. An electrochemical sensor is a device that combines a recognition element and an electrochemical transduction unit, where aptamers represent the latest addition to the large catalog of recognition elements. This chapter summarizes and evaluates recent developments of electrochemical aptamer-based sensors for microbial and viral pathogen detection, viability assessment of microorganisms, bacterial typing, identification of epitope-specific aptamers, affinity measurement between aptamers and their respective targets, and estimation of the degree of aptamer protection of oncolytic viruses for therapeutic purposes. PMID:23917779

Labib, Mahmoud; Berezovski, Maxim V

2014-01-01

10

Iridovirus infections in finfish - critical review with emphasis on ranaviruses.  

PubMed

Viruses in three genera of the family Iridoviridae (iridoviruses) affect finfish. Ranaviruses and megalocytiviruses are recently emerged pathogens. Both cause severe systemic disease, occur globally and affect a diversity of hosts. In contrast, lymphocystiviruses cause superficial lesions and rarely cause economic loss. The ranavirus epizootic haematopoietic necrosis virus (EHNV) from Australia was the first iridovirus to cause epizootic mortality in finfish. Like other ranaviruses, it lacks host specificity. A distinct but closely related virus, European catfish virus, occurs in finfish in Europe, while very similar ranaviruses occur in amphibians in Europe, Asia, Australia, North America and South America. These viruses can be distinguished from one another by conserved differences in the sequence of the major capsid protein gene, which informs policies of the World Organisation for Animal Health to minimize transboundary spread of these agents. However, limited epidemiological information and variations in disease expression create difficulties for design of sampling strategies for surveillance. There is still uncertainty surrounding the taxonomy of some putative ranaviruses such as Singapore grouper iridovirus and Santee-Cooper ranavirus, both of which cause serious disease in fish, and confusion continues with diseases caused by megalocytiviruses. In this review, aspects of the agents and diseases caused by ranaviruses are contrasted with those due to megalocytiviruses to promote accurate diagnosis and characterization of the agents responsible. Ranavirus epizootics in amphibians are also discussed because of possible links with finfish and common anthropogenic mechanisms of spread. The source of the global epizootic of disease caused by systemic iridoviruses in finfish and amphibians is uncertain, but three possibilities are discussed: trade in food fish, trade in ornamental fish, reptiles and amphibians and emergence from unknown reservoir hosts associated with environmental change. PMID:20050967

Whittington, R J; Becker, J A; Dennis, M M

2010-02-01

11

Susceptibility of pike Esox lucius to a panel of Ranavirus isolates.  

PubMed

In order to study the pathogenicity of ranaviruses to a wild European freshwater fish species, pike Esox lucius fry were challenged with the following Ranavirus isolates: epizootic haematopoietic necrosis virus (EHNV), European sheatfish virus (ESV), European catfish virus (ECV), pike-perch iridovirus (PPIV), New Zealand eel virus (NZeelV) and frog virus 3 (FV3). The fry were infected using bath challenge at 12 and 22 degrees C. Significant mortalities were observed at 12 degrees C for EHNV, ESV, PPIV and NZeelV. Background mortality was too high in the experiments performed at 22 degrees C for any conclusions about viral pathogenicity at this temperature to be drawn. Viruses could be re-isolated from samples from all challenged groups, and their presence in infected tissue was demonstrated using immunohistochemistry. The findings suggest that pike fry are susceptible to EHNV, ESV, PPIV and NZeelV and can be a vector for ECV and FV3. Statistical analysis of the factors associated with positive virus re-isolation showed that the number of fish in the sample influenced the outcome of virus re-isolation. Moreover, the likelihood of positive virus re-isolation significantly differed among the 6 viral isolates. The temperature from where the sample was taken and the number of days after infection were not associated with the probability of a positive virus re-isolation. PMID:19402450

Jensen, Britt Bang; Ersbøll, Annette Kjaer; Ariel, Ellen

2009-02-25

12

Comparative study of ranavirus isolates from cod (Gadus morhua) and turbot (Psetta maxima) with reference to other ranaviruses.  

PubMed

Two iridovirus isolates recovered from cod (Gadus morhua) and turbot (Psetta maxima) in Denmark were examined in parallel with a panel of other ranaviruses including frog virus 3 (FV3), the reference strain for the genus Ranavirus. The isolates were assessed according to their reactivity in immunofluoresent antibody tests (IFAT) using both homologous and heterologous antisera and their amplification in PCR using primers targeting five genomic regions. The corresponding PCR fragments were sequenced, and the sequences obtained were used in phylogenetic analysis. In addition, the pathogenicity to rainbow trout under experimental challenge conditions was investigated. The viruses were serologically and genetically closely related to highly pathogenic ranaviruses such as European catfish iridovirus (ECV), European sheatfish iridovirus (ESV) and epizootic haematopoietic necrosis virus (EHNV). The challenge trials indicate that rainbow trout fry cultured at 15 degrees C are not target species for the virus isolates in the present panel. We suggest that the two isolates belong in the genus Ranavirus and propose the name Ranavirus maxima (Rmax) for the turbot isolate. PMID:20552236

Ariel, Ellen; Holopainen, Riikka; Olesen, Niels Jørgen; Tapiovaara, Hannele

2010-08-01

13

Amphibian chytrid fungus and ranaviruses in the Northwest Territories, Canada.  

PubMed

Pathogens can cause serious declines in host species, and knowing where pathogens associated with host declines occur facilitates understanding host-pathogen ecology. Suspected drivers of global amphibian declines include infectious diseases, with 2 pathogens in particular, Batrachochytrium dendrobatidis (Bd) and ranaviruses, causing concern. We explored the host range and geographic distribution of Bd and ranaviruses in the Taiga Plains ecoregion of the Northwest Territories, Canada, in 2007 and 2008. Both pathogens were detected, greatly extending their known geographic distributions. Ranaviruses were widespread geographically, but found only in wood frogs. In contrast, Bd was found at a single site, but was detected in all 3 species of amphibians in the survey area (wood frogs, boreal chorus frogs, western toads). The presence of Bd in the Northwest Territories is not congruent with predicted distributions based on niche models, even though findings from other studies at northern latitudes are consistent with those same models. Unexpectedly, we also found evidence that swabs routinely used to collect samples for Bd screening detected fewer infections than toe clips. Our use and handling of the swabs was consistent with other studies, and the cause of the apparent lack of integrity of swabs is unknown. The ranaviruses detected in our study were confirmed to be Frog Virus 3 by sequence analysis of a diagnostic 500 bp region of the major capsid protein gene. It is unknown whether Bd or ranaviruses are recent arrivals to the Canadian north. However, the genetic analyses required to answer that question can inform larger debates about the origin of Bd in North America as well as the potential effects of climate change and industrial development on the distributions of these important amphibian pathogens. PMID:21268986

Schock, Danna M; Ruthig, Gregory R; Collins, James P; Kutz, Susan J; Carrière, Suzanne; Gau, Robert J; Veitch, Alasdair M; Larter, Nicholas C; Tate, Douglas P; Guthrie, Glen; Allaire, Daniel G; Popko, Richard A

2010-11-01

14

Expression analysis of immune response genes in fish epithelial cells following ranavirus infection.  

PubMed

Ranaviruses (family Iridoviridae) are a growing threat to fish and amphibian populations worldwide. The immune response to ranavirus infection has been studied in amphibians, but little is known about the responses elicited in piscine hosts. In this study, the immune response and apoptosis induced by ranaviruses were investigated in fish epithelial cells. Epithelioma papulosum cyprini (EPC) cells were infected with four different viral isolates: epizootic haematopoietic necrosis virus (EHNV), frog virus 3 (FV3), European catfish virus (ECV) and doctor fish virus (DFV). Quantitative real-time PCR (qPCR) assays were developed to measure the mRNA expression of immune response genes during ranavirus infection. The target genes included tumour necrosis factor ? (TNF-?), interleukin-1? (IL-1?), ?2-microglobulin (?2M), interleukin-10 (IL-10) and transforming growth factor ? (TGF-?). All ranaviruses elicited changes in immune gene expression. EHNV and FV3 caused a strong pro-inflammatory response with an increase in the expression of both IL-1? and TNF-?, whereas ECV and DFV evoked transient up-regulation of regulatory cytokine TGF-?. Additionally, all viral isolates induced increased ?2M expression as well as apoptosis in the EPC cells. Our results indicate that epithelial cells can serve as an in vitro model for studying the mechanisms of immune response in the piscine host in the first stages of ranavirus infection. PMID:22452879

Holopainen, Riikka; Tapiovaara, Hannele; Honkanen, Jarno

2012-06-01

15

Quantitation of ranaviruses in cell culture and tissue samples.  

PubMed

A quantitative real-time PCR (qPCR) based on a standard curve was developed for detection and quantitation of ranaviruses. The target gene for the qPCR was viral DNA polymerase (DNApol). All ten ranavirus isolates studied (Epizootic haematopoietic necrosis virus, EHNV; European catfish virus, ECV; European sheatfish virus, ESV; Frog virus 3, FV3; Bohle iridovirus, BIV; Doctor fish virus, DFV; Guppy virus 6, GV6; Pike-perch iridovirus, PPIV; Rana esculenta virus Italy 282/I02, REV282/I02 and Short-finned eel ranavirus, SERV) were detected with the qPCR assay. In addition, two fish cell lines - epithelioma papulosum cyprini (EPC) and bluegill fry (BF-2) - were infected with four of the isolates (EHNV, ECV, FV3 and DFV), and the viral quantity was determined from seven time points during the first three days after infection. The qPCR was also used to determine the viral load in tissue samples from pike (Esox lucius) fry challenged experimentally with EHNV. PMID:21087639

Holopainen, Riikka; Honkanen, Jarno; Jensen, Britt Bang; Ariel, Ellen; Tapiovaara, Hannele

2011-01-01

16

Richness and composition of niche-assembled viral pathogen communities.  

PubMed

The pathogen and parasite community that inhabits every free-living organism can control host vital rates including lifespan and reproductive output. To date, however, there have been few experiments examining pathogen community assembly replicated at large-enough spatial scales to inform our understanding of pathogen dynamics in natural systems. Pathogen community assembly may be driven by neutral stochastic colonization and extinction events or by niche differentiation that constrains pathogen distributions to particular environmental conditions, hosts, or vectors. Here, we present results from a regionally-replicated experiment investigating the community of barley and cereal yellow dwarf viruses (B/CYDV's) in over 5000 experimentally planted individuals of six grass species along a 700 km latitudinal gradient along the Pacific coast of North America (USA) in response to experimentally manipulated nitrogen and phosphorus supplies. The composition of the virus community varied predictably among hosts and across nutrient-addition treatments, indicating niche differentiation among virus species. There were some concordant responses among the viral species. For example, the prevalence of most viral species increased consistently with perennial grass cover, leading to a 60% increase in the richness of the viral community within individual hosts (i.e., coinfection) in perennial-dominated plots. Furthermore, infection rates of the six host species in the field were highly correlated with vector preferences assessed in laboratory trials. Our results reveal the importance of niche differentiation in structuring virus assemblages. Virus species distributions reflected a combination of local host community composition, host species-specific vector preferences, and virus responses to host nutrition. In addition, our results suggest that heterogeneity among host species in their capacity to attract vectors or support pathogens between growing seasons can lead to positive covariation among virus species. PMID:23468848

Seabloom, Eric W; Borer, Elizabeth T; Lacroix, Christelle; Mitchell, Charles E; Power, Alison G

2013-01-01

17

Richness and Composition of Niche-Assembled Viral Pathogen Communities  

PubMed Central

The pathogen and parasite community that inhabits every free-living organism can control host vital rates including lifespan and reproductive output. To date, however, there have been few experiments examining pathogen community assembly replicated at large-enough spatial scales to inform our understanding of pathogen dynamics in natural systems. Pathogen community assembly may be driven by neutral stochastic colonization and extinction events or by niche differentiation that constrains pathogen distributions to particular environmental conditions, hosts, or vectors. Here, we present results from a regionally-replicated experiment investigating the community of barley and cereal yellow dwarf viruses (B/CYDV's) in over 5000 experimentally planted individuals of six grass species along a 700 km latitudinal gradient along the Pacific coast of North America (USA) in response to experimentally manipulated nitrogen and phosphorus supplies. The composition of the virus community varied predictably among hosts and across nutrient-addition treatments, indicating niche differentiation among virus species. There were some concordant responses among the viral species. For example, the prevalence of most viral species increased consistently with perennial grass cover, leading to a 60% increase in the richness of the viral community within individual hosts (i.e., coinfection) in perennial-dominated plots. Furthermore, infection rates of the six host species in the field were highly correlated with vector preferences assessed in laboratory trials. Our results reveal the importance of niche differentiation in structuring virus assemblages. Virus species distributions reflected a combination of local host community composition, host species-specific vector preferences, and virus responses to host nutrition. In addition, our results suggest that heterogeneity among host species in their capacity to attract vectors or support pathogens between growing seasons can lead to positive covariation among virus species.

Seabloom, Eric W.; Borer, Elizabeth T.; Lacroix, Christelle; Mitchell, Charles E.; Power, Alison G.

2013-01-01

18

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

19

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

20

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

21

First evidence of amphibian chytrid fungus (Batrachochytrium dendrobatidis) and ranavirus in Hong Kong amphibian trade.  

PubMed

The emerging infectious amphibian diseases caused by amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranaviruses are responsible for global amphibian population declines and extinctions. Although likely to have been spread by a variety of activities, transcontinental dispersal appears closely associated with the international trade in live amphibians. The territory of Hong Kong reports frequent, high volume trade in amphibians, and yet the presence of Bd and ranavirus have not previously been detected in either traded or free-ranging amphibians. In 2012, a prospective surveillance project was conducted to investigate the presence of these pathogens in commercial shipments of live amphibians exported from Hong Kong International Airport. Analysis of skin (Bd) and cloacal (ranavirus) swabs by quantitative PCR detected pathogen presence in 31/265 (11.7%) and in 105/185 (56.8%) of amphibians, respectively. In addition, the water in which animals were transported tested positive for Bd, demonstrating the risk of pathogen pollution by the disposal of untreated wastewater. It is uncertain whether Bd and ranavirus remain contained within Hong Kong's trade sector, or if native amphibians have already been exposed. Rapid response efforts are now urgently needed to determine current pathogen distribution in Hong Kong, evaluate potential trade-associated exposure to free-ranging amphibians, and identify opportunities to prevent disease establishment. PMID:24599268

Kolby, Jonathan E; Smith, Kristine M; Berger, Lee; Karesh, William B; Preston, Asa; Pessier, Allan P; Skerratt, Lee F

2014-01-01

22

Susceptibility of fish and turtles to three ranaviruses isolated from different ectothermic vertebrate classes.  

PubMed

Abstract Ranaviruses have been associated with mortality of lower vertebrates around the world. Frog virus 3 (FV3)-like ranaviruses have been isolated from different ectothermic vertebrate classes; however, few studies have demonstrated whether this pathogen can be transmitted among classes. Using FV3-like ranaviruses isolated from the American bullfrog Lithobates catesbeianus, eastern box turtle Terrapene carolina carolina, and Pallid Sturgeon Scaphirhynchus albus, we tested for the occurrence of interclass transmission (i.e., infection) and host susceptibility (i.e., percent mortality) for five juvenile fish and three juvenile turtle species exposed to each of these isolates. Exposure was administered via water bath (10(3) PFU/mL) for 3 d and survival was monitored for 28 d. Florida softshell turtles Apalone ferox experienced no mortality, but 10% and 20% of individuals became infected by the turtle and fish isolate, respectively. Similarly, 5% of Mississippi map turtles Graptemys pseudogeographica kohni were subclinically infected with the turtle isolate at the end of the experiment. Channel Catfish Ictalurus punctatus experienced 5% mortality when exposed to the turtle isolate, while Western Mosquitofish Gambusia affinis experienced 10% mortality when exposed to the turtle and amphibian isolates and 5% mortality when exposed to the fish isolate. Our results demonstrated that interclass transmission of FV3-like ranaviruses is possible. Although substantial mortality did not occur in our experiments, the occurrence of low mortality and subclinical infections suggest that fish and aquatic turtles may function as reservoirs for FV3-like ranaviruses. Additionally, our study is the first to report transmission of FV3-like ranaviruses between fish and chelonians. Received October 22, 2013; accepted January 8, 2014. PMID:24895866

Brenes, Roberto; Miller, Debra L; Waltzek, Thomas B; Wilkes, Rebecca P; Tucker, Jennifer L; Chaney, Jordan C; Hardman, Rebecca H; Brand, Mabre D; Huether, Rebecca R; Gray, Matthew J

2014-06-01

23

Using a Pan-Viral Microarray Assay (Virochip) to Screen Clinical Samples for Viral Pathogens  

PubMed Central

The diagnosis of viral causes of many infectious diseases is difficult due to the inherent sequence diversity of viruses as well as the ongoing emergence of novel viral pathogens, such as SARS coronavirus and 2009 pandemic H1N1 influenza virus, that are not detectable by traditional methods. To address these challenges, we have previously developed and validated a pan-viral microarray platform called the Virochip with the capacity to detect all known viruses as well as novel variants on the basis of conserved sequence homology1. Using the Virochip, we have identified the full spectrum of viruses associated with respiratory infections, including cases of unexplained critical illness in hospitalized patients, with a sensitivity equivalent to or superior to conventional clinical testing2-5. The Virochip has also been used to identify novel viruses, including the SARS coronavirus6,7, a novel rhinovirus clade5, XMRV (a retrovirus linked to prostate cancer)8, avian bornavirus (the cause of a wasting disease in parrots)9, and a novel cardiovirus in children with respiratory and diarrheal illness10. The current version of the Virochip has been ported to an Agilent microarray platform and consists of ~36,000 probes derived from over ~1,500 viruses in GenBank as of December of 2009. Here we demonstrate the steps involved in processing a Virochip assay from start to finish (~24 hour turnaround time), including sample nucleic acid extraction, PCR amplification using random primers, fluorescent dye incorporation, and microarray hybridization, scanning, and analysis.

Chen, Eunice C.; Miller, Steve A.; DeRisi, Joseph L.; Chiu, Charles Y.

2011-01-01

24

Using a pan-viral microarray assay (Virochip) to screen clinical samples for viral pathogens.  

PubMed

The diagnosis of viral causes of many infectious diseases is difficult due to the inherent sequence diversity of viruses as well as the ongoing emergence of novel viral pathogens, such as SARS coronavirus and 2009 pandemic H1N1 influenza virus, that are not detectable by traditional methods. To address these challenges, we have previously developed and validated a pan-viral microarray platform called the Virochip with the capacity to detect all known viruses as well as novel variants on the basis of conserved sequence homology. Using the Virochip, we have identified the full spectrum of viruses associated with respiratory infections, including cases of unexplained critical illness in hospitalized patients, with a sensitivity equivalent to or superior to conventional clinical testing. The Virochip has also been used to identify novel viruses, including the SARS coronavirus, a novel rhinovirus clade, XMRV (a retrovirus linked to prostate cancer), avian bornavirus (the cause of a wasting disease in parrots), and a novel cardiovirus in children with respiratory and diarrheal illness. The current version of the Virochip has been ported to an Agilent microarray platform and consists of ~36,000 probes derived from over ~1,500 viruses in GenBank as of December of 2009. Here we demonstrate the steps involved in processing a Virochip assay from start to finish (~24 hour turnaround time), including sample nucleic acid extraction, PCR amplification using random primers, fluorescent dye incorporation, and microarray hybridization, scanning, and analysis. PMID:21559002

Chen, Eunice C; Miller, Steve A; DeRisi, Joseph L; Chiu, Charles Y

2011-01-01

25

The value of HIV protective epitope research for informed vaccine design against diverse viral pathogens.  

PubMed

The success of vaccine regimens against viral pathogens hinges on the elicitation of protective responses. Hypervariable pathogens such as HIV avoid neutralization by masking protective epitopes with more immunogenic decoys. The identification of protective, conserved epitopes is crucial for future vaccine candidate design. The strategies employed for identification of HIV protective epitopes will also aid towards rational vaccine design for other viral pathogens. PMID:24964950

Kramer, Victor G; Byrareddy, Siddappa N

2014-08-01

26

Mechanisms of RIG-I-Like Receptor Activation and Manipulation by Viral Pathogens.  

PubMed

RIG-I-like receptors (RLRs) play important roles in the host defense to numerous viral pathogens. Since they were discovered, much light has been shed on the molecular details of how these cytoplasmic viral RNA receptors sense viral infection and orchestrate antiviral innate immunity. Intriguingly, in addition to viral RNA binding, a series of posttranslational modifications (PTMs) is required for the rapid activation of RLRs and, inversely, for the prevention of aberrant innate immune signaling. Recent discoveries have shown that viruses manipulate the PTMs of RLRs to escape innate immune detection. This article highlights some of these recent findings in this fast-evolving field. PMID:24623415

Gack, Michaela U

2014-05-01

27

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

28

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...

29

Susceptibility of black bullhead Ameiurus melas to a panel of ranavirus isolates.  

PubMed

Ranaviruses are considered a serious threat to lower vertebrates, including fish, amphibians and reptiles. However, epidemiological data on these agents are lacking, and further investigations are needed to understand the role of carriers and to update the list of susceptible hosts. We carried out various experimental infections under controlled conditions to contribute to the current knowledge on the susceptibility of black bullhead Ameiurus melas to European catfish virus (ECV) and other ranaviruses. A panel of 7 ranavirus isolates was used to challenge duplicate groups of A. melas juveniles maintained in aquaria supplied with running dechlorinated tap water. The experiments were performed at 15 and 25 degrees C. The results confirmed the high susceptibility of A. melas to ECV infection. Furthermore, a significant mortality associated with the typical signs of systemic viral infections was observed in groups challenged with Epizootic haematopoietic necrosis virus (EHNV) at 25 degrees C, and to a lesser extent, at 15 degrees C. No significant mortality was recorded in fish challenged with European sheatfish virus (ESV), Frog virus 3 (FV3), Rana esculenta virus-like (REV-like), Bohle iridovirus (BIV) or short-finned eel virus (SERV). PMID:20815324

Gobbo, F; Cappellozza, E; Pastore, M R; Bovo, G

2010-07-01

30

Roles of HIV1 auxiliary proteins in viral pathogenesis and host-pathogen interactions  

Microsoft Academic Search

Active host-pathogen interactions take place during infection of human immunodeficiency virus type 1 (HIV-1). Outcomes of these interactions determine the efficiency of viral infection and subsequent disease progression. HIV-infected cells respond to viral invasion with various defensive strategies such as innate, cellular and humoral immune antiviral mechanisms. On the other hand, the virus has also developed various offensive tactics to

Lin LI; Hai Shan LI; C David PAUZA; Michael BUKRINSKY; Richard Y ZHAO

2005-01-01

31

Detection of viral pathogens in high grade gliomas from unmapped next-generation sequencing data.  

PubMed

Viral pathogens have been implicated in the development of certain cancers including human papillomavirus (HPV) in squamous cell carcinoma and Epstein-Barr virus (EBV) in Burkitt's lymphoma. The significance of viral pathogens in brain tumors is controversial, and human cytomegalovirus (HCMV) has been associated with glioblastoma (GBM) in some but not all studies, making the role of HCMV unclear. In this study we sought to determine if viral pathogen sequences could be identified in an unbiased manner from previously discarded, unmapped, non-human, next-generation sequencing (NGS) reads obtained from targeted oncology, panel-based sequencing of high grade gliomas (HGGs), including GBMs. Twenty one sequential HGG cases were analyzed by a targeted NGS clinical oncology panel containing 151 genes using DNA obtained from formalin-fixed, paraffin-embedded (FFPE) tissue. Sequencing reads that did not map to the human genome (average of 38,000 non-human reads/case (1.9%)) were filtered and low quality reads removed. Extracted high quality reads were then sequentially aligned to the National Center for Biotechnology Information (NCBI) non-redundant nucleotide (nt and nr) databases. Aligned reads were classified based on NCBI taxonomy database and all eukaryotic viral sequences were further classified into viral families. Two viral sequences (both herpesviruses), EBV and Roseolovirus were detected in 5/21 (24%) cases and in 1/21 (5%) cases, respectively. None of the cases had detectable HCMV. Of the five HGG cases with detectable EBV DNA, four had additional material for EBV in situ hybridization (ISH), all of which were negative for expressed viral sequence. Overall, a similar discovery approach using unmapped non-human NGS reads could be used to discover viral sequences in other cancer types. PMID:24704430

Cimino, Patrick J; Zhao, Guoyan; Wang, David; Sehn, Jennifer K; Lewis, James S; Duncavage, Eric J

2014-06-01

32

Unbiased parallel detection of viral pathogens in clinical samples by use of a metagenomic approach.  

PubMed

Viral infectious diseases represent a major threat to public health and are among the greatest disease burdens worldwide. Rapid and accurate identification of viral agents is crucial for both outbreak control and estimating regional disease burdens. Recently developed metagenomic methods have proven to be powerful tools for simultaneous pathogen detection. Here, we performed a systematic study of the capability of the short-read-based metagenomic approach in the molecular detection of viral pathogens in nasopharyngeal aspirate samples from patients with acute lower respiratory tract infections (n = 16). Using the high-throughput capacity of ultradeep sequencing and a dedicated data interpretation method, we successfully identified seven species of known respiratory viral agents from 15 samples, a result that was consistent with results of conventional PCR assays. We also detected a coinfected case that was missed by regular PCR testing. Using the metagenomic data, 11 draft genomes of the abundantly detected viruses in the samples were reconstructed with 21.84% to 98.53% coverage. Our results show the power of the short-read-based metagenomic approach for accurate and parallel screening of viral pathogens. Although there are some inherent difficulties in applying this approach to clinical samples, including a lack of controls, limited specimen quantity, and high contamination rate, our work will facilitate further application of this unprecedented high-throughput method to clinical samples. PMID:21813714

Yang, Jian; Yang, Fan; Ren, Lili; Xiong, Zhaohui; Wu, Zhiqiang; Dong, Jie; Sun, Lilian; Zhang, Ting; Hu, Yongfeng; Du, Jiang; Wang, Jianwei; Jin, Qi

2011-10-01

33

VIRAL PATHOGENS AND MICROBIOLOGICAL INDICATORS IN GROUND WATER FROM SMALL PUBLIC WATER SUPPLIES IN SOUTHEASTERN MICHIGAN  

EPA Science Inventory

Thirty-eight public ground-water-supply wells serving less than 3,300 people were sampled from July 1999 through July 2001 in southeastern Michigan to determine (1) occurrence of viral pathogens and microbiological indicators, (2) whether indicators are adequate predictors of the...

34

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

35

Rapid Accurate Identification of Bacterial and Viral Pathogens  

SciTech Connect

The goals of this program were to develop two assays for rapid, accurate identification of pathogenic organisms at the strain level. The first assay "Quantitative Genome Profiling or QGP" is a real time PCR assay with a restriction enzyme-based component. Its underlying concept is that certain enzymes should cleave genomic DNA at many sites and that in some cases these cuts will interrupt the connection on the genomic DNA between flanking PCR primer pairs thereby eliminating selected PCR amplifications. When this occurs the appearance of the real-time PCR threshold (Ct) signal during DNA amplification is totally eliminated or, if cutting is incomplete, greatly delayed compared to an uncut control. This temporal difference in appearance of the Ct signal relative to undigested control DNA provides a rapid, high-throughput approach for DNA-based identification of different but closely related pathogens depending upon the nucleotide sequence of the target region. The second assay we developed uses the nucleotide sequence of pairs of shmi identifier tags (-21 bp) to identify DNA molecules. Subtle differences in linked tag pair combinations can also be used to distinguish between closely related isolates..

Dunn, John

2007-03-09

36

Large scale comparison of innate responses to viral and bacterial pathogens in mouse and macaque.  

PubMed

Viral and bacterial infections of the lower respiratory tract are major causes of morbidity and mortality worldwide. Alveolar macrophages line the alveolar spaces and are the first cells of the immune system to respond to invading pathogens. To determine the similarities and differences between the responses of mice and macaques to invading pathogens we profiled alveolar macrophages from these species following infection with two viral (PR8 and Fuj/02 influenza A) and two bacterial (Mycobacterium tuberculosis and Francisella tularensis Schu S4) pathogens. Cells were collected at 6 time points following each infection and expression profiles were compared across and between species. Our analyses identified a core set of genes, activated in both species and across all pathogens that were predominantly part of the interferon response pathway. In addition, we identified similarities across species in the way innate immune cells respond to lethal versus non-lethal pathogens. On the other hand we also found several species and pathogen specific response patterns. These results provide new insights into mechanisms by which the innate immune system responds to, and interacts with, invading pathogens. PMID:21789257

Zinman, Guy; Brower-Sinning, Rachel; Emeche, Chineye H; Ernst, Jason; Huang, Grace Tzu-Wei; Mahony, Shaun; Myers, Amy J; O'Dee, Dawn M; Flynn, JoAnne L; Nau, Gerard J; Ross, Ted M; Salter, Russell D; Benos, Panayiotis V; Bar Joseph, Ziv; Morel, Penelope A

2011-01-01

37

Large Scale Comparison of Innate Responses to Viral and Bacterial Pathogens in Mouse and Macaque  

PubMed Central

Viral and bacterial infections of the lower respiratory tract are major causes of morbidity and mortality worldwide. Alveolar macrophages line the alveolar spaces and are the first cells of the immune system to respond to invading pathogens. To determine the similarities and differences between the responses of mice and macaques to invading pathogens we profiled alveolar macrophages from these species following infection with two viral (PR8 and Fuj/02 influenza A) and two bacterial (Mycobacterium tuberculosis and Francisella tularensis Schu S4) pathogens. Cells were collected at 6 time points following each infection and expression profiles were compared across and between species. Our analyses identified a core set of genes, activated in both species and across all pathogens that were predominantly part of the interferon response pathway. In addition, we identified similarities across species in the way innate immune cells respond to lethal versus non-lethal pathogens. On the other hand we also found several species and pathogen specific response patterns. These results provide new insights into mechanisms by which the innate immune system responds to, and interacts with, invading pathogens.

Zinman, Guy; Brower-Sinning, Rachel; Emeche, Chineye H.; Ernst, Jason; Huang, Grace Tzu-Wei; Mahony, Shaun; Myers, Amy J.; O'Dee, Dawn M.; Flynn, JoAnne L.; Nau, Gerard J.; Ross, Ted M.; Salter, Russell D.; Benos, Panayiotis V.; Bar Joseph, Ziv; Morel, Penelope A.

2011-01-01

38

Extraction of Total Nucleic Acids From Ticks for the Detection of Bacterial and Viral Pathogens  

PubMed Central

Ticks harbor numerous bacterial, protozoal, and viral pathogens that can cause serious infections in humans and domestic animals. Active surveillance of the tick vector can provide insight into the frequency and distribution of important pathogens in the environment. Nucleic-acid based detection of tick-borne bacterial, protozoan, and viral pathogens requires the extraction of both DNA and RNA (total nucleic acids) from ticks. Traditional methods for nucleic acid extraction are limited to extraction of either DNA or the RNA from a sample. Here we present a simple bead-beating based protocol for extraction of DNA and RNA from a single tick and show detection of Borrelia burgdorferi and Powassan virus from individual, infected Ixodes scapularis ticks. We determined expected yields for total nucleic acids by this protocol for a variety of adult tick species. The method is applicable to a variety of arthropod vectors, including fleas and mosquitoes, and was partially automated on a liquid handling robot.

Crowder, Chris D.; Rounds, Megan A.; Phillipson, Curtis A.; Picuri, John M.; Matthews, Heather E.; Halverson, Justina; Schutzer, Steven E.; Ecker, David J.; Eshoo, Mark W.

2010-01-01

39

Passive immunization against highly pathogenic Avian Influenza Virus (AIV) strain H7N3 with antiserum generated from viral polypeptides protect poultry birds from lethal viral infection  

Microsoft Academic Search

Our studies were aimed at developing a vaccination strategy that could provide protection against highly pathogenic avian influenza virus (AIV), H7N3 or its variants outbreaks. A purified viral stock of highly pathogenic H7N3 isolate was lysed to isolate viral proteins by electrophresing on 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), followed by their elution from gel through trituration in

Mirza Imran Shahzad; Khalid Naeem; Muhammad Mukhtar; Azra Khanum

2008-01-01

40

Viral Metagenome Analysis to Guide Human Pathogen Monitoring in Environmental Samples  

PubMed Central

Aims The aim of this study was to develop and demonstrate an approach for describing the diversity of human pathogenic viruses in an environmentally isolated viral metagenome. Methods and Results In silico bioinformatic experiments were used to select an optimum annotation strategy for discovering human viruses in virome datasets, and applied to annotate a class B biosolids virome. Results from the in silico study indicated that less than 1% errors in virus identification could be achieved when nucleotide-based search programs (BLASTn or tBLASTx), viral genome only databases, and sequence reads greater than 200 nt were considered. Within the 51,925 annotated sequences, 94 DNA and 19 RNA sequences were identified as human viruses. Virus diversity included environmentally transmitted agents such as parechovirus, coronavirus, adenovirus, and aichi virus, as well as viruses associated with chronic human infections such as human herpes and hepatitis C viruses. Conclusions This study provided a bioinformatic approach for identifying pathogens in a virome dataset, and demonstrated the human virus diversity in a relevant environmental sample. Significance and Impact of Study As the costs of next generation sequencing decrease, the pathogen diversity described by virus metagenomes will provide an unbiased guide for subsequent cell-culture and quantitative pathogen analyses, and ensures that highly enriched and relevant pathogens are not neglected in exposure and risk assessments.

Bibby, Kyle; Viau, Emily; Peccia, Jordan

2011-01-01

41

Catalog of Micro-Tom tomato responses to common fungal, bacterial, and viral pathogens  

Microsoft Academic Search

Lycopersicon esculentum cultivar Micro-Tom is a miniature tomato with many advantages for studies of the molecular biology and physiology of plants. To evaluate the suitability of Micro-Tom as a host plant for the study of pathogenesis, Micro-Tom plants were inoculated with 16 well-known fungal, bacterial, and viral pathogens of tomato. Athelia rolfsii, Botryotinia fuckeliana, Oidium sp., Phytophthora infestans, and Sclerotinia

Hideki Takahashi; Ayano Shimizu; Tsutomu Arie; Syofi Rosmalawati; Sumire Fukushima; Mari Kikuchi; Yasufumi Hikichi; Ayami Kanda; Akiko Takahashi; Akinori Kiba; Kohei Ohnishi; Yuki Ichinose; Fumiko Taguchi; Chihiro Yasuda; Motoichiro Kodama; Mayumi Egusa; Chikara Masuta; Hiroyuki Sawada; Daisuke Shibata; Koichi Hori; Yuichiro Watanabe

2005-01-01

42

An efficient diagnostic method for the identification of potato viral pathogens  

Microsoft Academic Search

Potato is commonly affected by various pathogens of viral, bacterial, and fungal origin; therefore, simple and accurate diagnostic\\u000a and identification techniques are of key importance both for the production of virus free planting material and for the monitoring\\u000a of the phytosanitary state of planting areas. The newly developed test systems based on qualitative fluorescent amplification-based\\u000a specific hybridization (FLASH-PCR) enable fast

D. Yu. Ryazantsev; S. K. Zavriev

2009-01-01

43

Identification of Viral Pathogen Diversity in Sewage Sludge by Metagenome Analysis  

PubMed Central

The large diversity of viruses that exist in human populations are potentially excreted into sewage collection systems and concentrated in sewage sludge. In the US, the primary fate of processed sewage sludge (class B biosolids) is application to agricultural land as a soil amendment. To characterize and understand infectious risks associated with land application, and to describe the diversity of viruses in human populations, shotgun viral metagenomics was applied to 10 sewage sludge samples from 5 wastewater treatment plants throughout the continental U.S, each serving between 100,000 and 1,000,000 people. Nearly 330 million DNA sequences were produced and assembled, and annotation resulted in identifying 43 (26 DNA, 17 RNA) different types of human viruses in sewage sludge. Novel insights include the high abundance of newly emerging viruses (e.g. Coronavirus HKU1, Klassevirus, and Cosavirus) the strong representation of respiratory viruses, and the relatively minor abundance and occurrence of Enteroviruses. Viral metagenome sequence annotations were reproducible and independent PCR-based identification of selected viruses suggests that viral metagenomes were a conservative estimate of the true viral occurrence and diversity. These results represent the most complete description of human virus diversity in any wastewater sample to date, provide engineers and environmental scientists with critical information on important viral agents and routes of infection from exposure to wastewater and sewage sludge, and represent a significant leap forward in understanding the pathogen content of class B biosolids.

BIBBY, KYLE; PECCIA, JORDAN

2013-01-01

44

Parasitic, bacterial, and viral enteric pathogens associated with diarrhea in the Central African Republic.  

PubMed Central

A total of 1,197 diarrheic children less than 15 years old were investigated for parasitic, bacterial, and viral enteropathogens from March 1981 through February 1982 in the Central African Republic. One or more pathogens were identified from 49.4% of the patients. Rotavirus was the most frequently identified pathogen among children less than 18 months old. Enteropathogenic Escherichia coli was the second most frequently isolated pathogen (12.1%) in children less than 2 years of age. Campylobacter jejuni was also isolated frequently from diarrheic children less than 5 years of age (10.9%). Entamoeba histolytica was identified in very young children and was found to be the most frequent enteropathogen associated with diarrhea in children over the age of 2 years. Enterotoxigenic Escherichia coli was rarely isolated (ca. 2%). There was a peak in the incidence of rotavirus during the dry season and in the incidence of Campylobacter jejuni during the rainy season.

Georges, M C; Wachsmuth, I K; Meunier, D M; Nebout, N; Didier, F; Siopathis, M R; Georges, A J

1984-01-01

45

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

46

Development of real-time PCR assays for the detection and differentiation of Australian and European ranaviruses.  

PubMed

Serious systemic disease in fish and amphibians is associated with the ranaviruses, epizootic haematopoietic necrosis virus (EHNV) and Bohle iridovirus (BIV) in Australia, and European sheatfish virus (ESV) and European catfish virus (ECV) in Europe. EHNV, ESV and ECV are recognized causative agents of the OIE (Office International des Epizooties) notifiable systemic necrotizing iridovirus syndrome and are currently identified by protein-based assays, none of which are able to rapidly identify the specific agents. The aim of this study was to develop TaqMan real-time PCR assays that differentiated these viruses using nucleotide sequence variation in two ranavirus genes. A conserved probe representing 100% sequence homology was used as a reference for virus-specific probes. The virus-specific probes produced a similar signal level to the conserved probe while those probes binding to non-target viral DNA produced an altered fluorescent curve. The pattern of probe binding was characteristic for each virus. Sensitivity, specificity and dynamic range of the assay were assessed. The test is currently useful as a research and initial screening tool, with the potential to become a sensitive and specific method for detection and differentiation of ranaviruses with further development. PMID:17584440

Pallister, J; Gould, A; Harrison, D; Hyatt, A; Jancovich, J; Heine, H

2007-07-01

47

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

48

Microbiological and pathological examination of fatal calf pneumonia cases induced by bacterial and viral respiratory pathogens.  

PubMed

The infectious origin of fatal cases of calf pneumonia was studied in 48 calves from 27 different herds on postmortem examination. Lung tissue samples were examined by pathological, histological, bacterial culture, virus isolation and immunohistochemical methods for the detection of viral and bacterial infections. Pneumonia was diagnosed in 47/48 cases and infectious agents were found in 40/47 (85%) of those cases. The presence of multiple respiratory pathogens in 23/40 (57.5%) cases indicated the complex origin of fatal calf pneumonia. The most important respiratory pathogens were Mannheimia-Pasteurella in 36/40 (90%) cases, followed by Arcanobacterium pyogenes in 16/40 (40%) cases, Mycoplasma bovis in 12/40 (30%) cases, and bovine respiratory syncytial virus in 4/40 (10%) cases. Histophilus somni was detected in 2/40 (5%) cases, while bovine herpesvirus-1, bovine viral diarrhoea virus and parainfluenza virus-3 were each found in 1/40 (2.5%) case. Mastadenovirus, bovine coronavirus, influenza A virus or Chlamydiaceae were not detected. PMID:20713325

Szeredi, Levente; Jánosi, Szilárd; Pálfi, Vilmos

2010-09-01

49

Extended Viral Shedding of a Low Pathogenic Avian Influenza Virus by Striped Skunks (Mephitis mephitis)  

PubMed Central

Background Striped skunks (Mephitis mephitis) are susceptible to infection with some influenza A viruses. However, the viral shedding capability of this peri-domestic mammal and its potential role in influenza A virus ecology are largely undetermined. Methodology/Principal Findings Striped skunks were experimentally infected with a low pathogenic (LP) H4N6 avian influenza virus (AIV) and monitored for 20 days post infection (DPI). All of the skunks exposed to H4N6 AIV shed large quantities of viral RNA, as detected by real-time RT-PCR and confirmed for live virus with virus isolation, from nasal washes and oral swabs (maximum ?106.02 PCR EID50 equivalent/mL and ?105.19 PCR EID50 equivalent/mL, respectively). Some evidence of potential fecal shedding was also noted. Following necropsy on 20 DPI, viral RNA was detected in the nasal turbinates of one individual. All treatment animals yielded evidence of a serological response by 20 DPI. Conclusions/Significance These results indicate that striped skunks have the potential to shed large quantities of viral RNA through the oral and nasal routes following exposure to a LP AIV. Considering the peri-domestic nature of these animals, along with the duration of shedding observed in this species, their presence on poultry and waterfowl operations could influence influenza A virus epidemiology. For example, this species could introduce a virus to a naive poultry flock or act as a trafficking mechanism of AIV to and from an infected poultry flock to naive flocks or wild bird populations.

Root, J. Jeffrey; Shriner, Susan A.; Bentler, Kevin T.; Gidlewski, Thomas; Mooers, Nicole L.; Ellis, Jeremy W.; Spraker, Terry R.; VanDalen, Kaci K.; Sullivan, Heather J.; Franklin, Alan B.

2014-01-01

50

Inducible nitric oxide contributes to viral pathogenesis following highly pathogenic influenza virus infection in mice.  

PubMed

Highly pathogenic influenza A viruses, including avian H5N1 viruses and the 1918 pandemic virus, cause severe respiratory disease in humans and animals. Virus infection is followed by intense pulmonary congestion due to an extensive influx of macrophages and neutrophils, which can release large quantities of reactive oxygen species potentially contributing to the pathogenesis of lung disease. Here, the role of nitric oxide (NO), a potent signaling molecule in inflammation, was evaluated following highly pathogenic influenza virus challenge in mice. We observed higher levels of NO in mice infected with H5N1 and 1918 viruses as compared to a seasonal H1N1 virus. Mice deficient in inducible NO synthase (NOS2(-/-)) exhibited reduced morbidity, reduced mortality, and diminished cytokine production in lung tissue following H5N1 and 1918-virus challenge, compared with wild-type control mice. Furthermore, systemic treatment of mice with the NOS inhibitor NG-monomethyl-l-arginine delayed weight loss and death among 1918 virus infected mice compared to untreated control animals. This study demonstrates that NO contributes to the pathogenic outcome of H5N1 and 1918 viral infections in the mouse model. PMID:23420903

Perrone, Lucy A; Belser, Jessica A; Wadford, Debra A; Katz, Jacqueline M; Tumpey, Terrence M

2013-05-15

51

Endogenous MMTV Proviruses Induce Susceptibility to Both Viral and Bacterial Pathogens  

PubMed Central

Most inbred mice carry germline proviruses of the retrovirus, mouse mammary tumor virus (MMTV) (called Mtvs), which have multiple replication defects. A BALB/c congenic mouse strain lacking all endogenous Mtvs (Mtv-null) was resistant to MMTV oral and intraperitoneal infection and tumorigenesis compared to wild-type BALB/c mice. Infection of Mtv-null mice with an MMTV-related retrovirus, type B leukemogenic virus, also resulted in severely reduced viral loads and failure to induce T-cell lymphomas, indicating that resistance is not dependent on expression of a superantigen (Sag) encoded by exogenous MMTV. Resistance to MMTV in Mtv-null animals was not due to neutralizing antibodies. Further, Mtv-null mice were resistant to rapid mortality induced by intragastric inoculation of the Gram-negative bacterium, Vibrio cholerae, but susceptibility to Salmonella typhimurium was not significantly different from BALB/c mice. Susceptibility to both MMTV and V. cholerae was reconstituted by the presence of any one of three endogenous Mtvs located on different chromosomes and was associated with increased pathogen load. One of these endogenous proviruses is known to encode only Sag. Therefore, Mtv-encoded Sag appears to provide a unique genetic susceptibility to specific viruses and bacteria. Since human endogenous retroviruses also encode Sags, these studies have broad implications for pathogen-induced responses in mice and humans.

Bhadra, Sanchita; Lozano, Mary M; Payne, Shelley M; Dudley, Jaquelin P

2006-01-01

52

Pathogen host switching in commercial trade with management recommendations.  

PubMed

Global wildlife trade exacerbates the spread of nonindigenous species. Pathogens also move with hosts through trade and often are released into naïve populations with unpredictable outcomes. Amphibians are moved commercially for pets, food, bait, and biomedicine, and are an excellent model for studying how wildlife trade relates to pathogen pollution. Ranaviruses are amphibian pathogens associated with annual population die-offs; multiple strains of tiger salamander ranaviruses move through the bait trade in the western United States. Ranaviruses infect amphibians, reptiles, and fish and are of additional concern because they can switch hosts. Tiger salamanders are used as live bait for freshwater fishing and are a potential source for ranaviruses switching hosts from amphibians to fish. We experimentally injected largemouth bass with a bait trade tiger salamander ranavirus. Largemouth bass became infected but exhibited no signs of disease or mortality. Amphibian bait ranaviruses have the potential to switch hosts to infect fish, but fish may act as dead-end hosts or nonsymptomatic carriers, potentially spreading infection as a result of trade. PMID:20411298

Picco, Angela M; Karam, Abraham P; Collins, James P

2010-06-01

53

Respiratory viral pathogens among Singapore military servicemen 2009 - 2012: epidemiology and clinical characteristics  

PubMed Central

Background Few studies have comprehensively described tropical respiratory disease surveillance in military populations. There is also a lack of studies comparing clinical characteristics of the non-influenza pathogens with influenza and amongst themselves. Methods From May 2009 through October 2012, 7733 consenting cases of febrile respiratory illness (FRI) (temperature [greater than or equal to]37.5degreesC with cough or sorethroat) and controls in the Singapore military had clinical data and nasal washes collected prospectively. Nasal washes underwent multiplex PCR, and the analysis was limited to viral mono-infections. Results 49% of cases tested positive for at least one virus, of whom 10% had multiple infections. 53% of the FRI cases fulfilled the definition of influenza-like illness (ILI), of whom 52% were positive for at least one virus. The most frequent etiologies for mono-infections among FRI cases were Influenza A(H1N1)pdm09 (13%), Influenza B (13%) and coxsackevirus (9%). The sensitivity, specificity, positive predictive value and negative predictive value of ILI for influenza among FRI cases were 72%, 48%, 40% and 69% respectively. On logistic regression, there were marked differences in the prevalence of different symptoms and signs between viruses with fever more prevalent amongst influenza and adenovirus infections than other viruses. Conclusion There are multiple viral etiologies for FRI and ILI with differing clinical symptoms in the Singapore military. Influenza and coxsackevirus were the most common etiology for FRI, while influenza and adenoviruses displayed the most febrile symptoms. Further studies should explore these differences and possible interventions.

2014-01-01

54

Neonicotinoid clothianidin adversely affects insect immunity and promotes replication of a viral pathogen in honey bees  

PubMed Central

Large-scale losses of honey bee colonies represent a poorly understood problem of global importance. Both biotic and abiotic factors are involved in this phenomenon that is often associated with high loads of parasites and pathogens. A stronger impact of pathogens in honey bees exposed to neonicotinoid insecticides has been reported, but the causal link between insecticide exposure and the possible immune alteration of honey bees remains elusive. Here, we demonstrate that the neonicotinoid insecticide clothianidin negatively modulates NF-?B immune signaling in insects and adversely affects honey bee antiviral defenses controlled by this transcription factor. We have identified in insects a negative modulator of NF-?B activation, which is a leucine-rich repeat protein. Exposure to clothianidin, by enhancing the transcription of the gene encoding this inhibitor, reduces immune defenses and promotes the replication of the deformed wing virus in honey bees bearing covert infections. This honey bee immunosuppression is similarly induced by a different neonicotinoid, imidacloprid, but not by the organophosphate chlorpyriphos, which does not affect NF-?B signaling. The occurrence at sublethal doses of this insecticide-induced viral proliferation suggests that the studied neonicotinoids might have a negative effect at the field level. Our experiments uncover a further level of regulation of the immune response in insects and set the stage for studies on neural modulation of immunity in animals. Furthermore, this study has implications for the conservation of bees, as it will contribute to the definition of more appropriate guidelines for testing chronic or sublethal effects of pesticides used in agriculture.

Di Prisco, Gennaro; Cavaliere, Valeria; Annoscia, Desiderato; Varricchio, Paola; Caprio, Emilio; Nazzi, Francesco; Gargiulo, Giuseppe; Pennacchio, Francesco

2013-01-01

55

Neonicotinoid clothianidin adversely affects insect immunity and promotes replication of a viral pathogen in honey bees.  

PubMed

Large-scale losses of honey bee colonies represent a poorly understood problem of global importance. Both biotic and abiotic factors are involved in this phenomenon that is often associated with high loads of parasites and pathogens. A stronger impact of pathogens in honey bees exposed to neonicotinoid insecticides has been reported, but the causal link between insecticide exposure and the possible immune alteration of honey bees remains elusive. Here, we demonstrate that the neonicotinoid insecticide clothianidin negatively modulates NF-?B immune signaling in insects and adversely affects honey bee antiviral defenses controlled by this transcription factor. We have identified in insects a negative modulator of NF-?B activation, which is a leucine-rich repeat protein. Exposure to clothianidin, by enhancing the transcription of the gene encoding this inhibitor, reduces immune defenses and promotes the replication of the deformed wing virus in honey bees bearing covert infections. This honey bee immunosuppression is similarly induced by a different neonicotinoid, imidacloprid, but not by the organophosphate chlorpyriphos, which does not affect NF-?B signaling. The occurrence at sublethal doses of this insecticide-induced viral proliferation suggests that the studied neonicotinoids might have a negative effect at the field level. Our experiments uncover a further level of regulation of the immune response in insects and set the stage for studies on neural modulation of immunity in animals. Furthermore, this study has implications for the conservation of bees, as it will contribute to the definition of more appropriate guidelines for testing chronic or sublethal effects of pesticides used in agriculture. PMID:24145453

Di Prisco, Gennaro; Cavaliere, Valeria; Annoscia, Desiderato; Varricchio, Paola; Caprio, Emilio; Nazzi, Francesco; Gargiulo, Giuseppe; Pennacchio, Francesco

2013-11-12

56

Development of Real-Time PCR Array for Simultaneous Detection of Eight Human Blood-Borne Viral Pathogens  

PubMed Central

Background Real-time PCR array for rapid detection of multiple viral pathogens should be highly useful in cases where the sample volume and the time of testing are limited, i.e. in the eligibility testing of tissue and organ donors. Findings We developed a real-time PCR array capable of simultaneously detecting eight human viral pathogens: human immunodeficiency virus types 1 and 2 (HIV-1 and -2), hepatitis B virus (HBV), hepatitis C virus (HCV), human T-cell leukemia virus-1 and -2 (HTLV-1 and -2), vaccinia virus (VACV) and West Nile virus (WNV). One hundred twenty (120) primers were designed using a combination of bioinformatics approaches, and, after experimental testing, 24 primer sets targeting eight viral pathogens were selected to set up the array with SYBR Green chemistry. The specificity and sensitivity of the virus-specific primer sets selected for the array were evaluated using analytical panels with known amounts of viruses spiked into human plasma. The array detected: 10 genome equivalents (geq)/ml of HIV-2 and HCV, 50 geq of HIV-1 (subtype B), HBV (genotype A) and WNV. It detected 100–1,000 geq/ml of plasma of HIV-1 subtypes (A – G), group N and CRF (AE and AG) isolates. Further evaluation with a panel consisting of 28 HIV-1 and HIV-2 clinical isolates revealed no cross-reactivity of HIV-1 or HIV-2 specific primers with another type of HIV. All 28 viral isolates were identified with specific primer sets targeting the most conserved genome areas. The PCR array correctly identified viral infections in a panel of 17 previously quantified clinical plasma samples positive for HIV-1, HCV or HBV at as low as several geq per PCR reaction. Conclusions The viral array described here demonstrated adequate performance in the testing of donors’ clinical samples. Further improvement in its sensitivity for the broad spectrum of HIV-1 subtypes is under development.

Pripuzova, Natalia; Wang, Richard; Tsai, Shien; Li, Bingjie; Hung, Guo-Chiuan; Ptak, Roger G.; Lo, Shyh-Ching

2012-01-01

57

RANAVIRUS INFECTION OF FREE-RANGING AND CAPTIVE BOX TURTLES AND TORTOISES IN THE UNITED STATES  

Microsoft Academic Search

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

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

2008-01-01

58

Comparison of the eIF-2alpha homologous proteins of seven ranaviruses (Iridoviridae).  

PubMed

The alpha-subunit of the eukaryotic initiation factor 2 (eIF-2alpha) is a key component of the translation machinery of the cell. In response to cellular stress such as viral infections, eIF-2alpha is phosphorylated by double-stranded RNA-dependent protein kinase (PKR) leading to the inhibition of cellular protein synthesis. The importance of eIF-2alpha as a regulatory mechanism for protein synthesis is illustrated by the wide variety of strategies employed by viruses to down-regulate PKR. Thus, Vaccinia virus encodes K3L protein, which resembles eIF-2alpha and acts as a pseudo-substrate inhibitor of PKR. Nucleotide sequencing of the genome of epizootic haematopoietic necrosis virus (EHNV), a member of the genus ranavirus of Iridoviridae, has revealed an eIF-2alpha equivalent gene. We have cloned and sequenced eIF-2alpha genes of several iridoviruses of fishes and frogs. The eIF-2alpha open reading frames and deduced proteins of the iridoviruses investigated exhibit a high degree of homology of both nucleotide and amino acid sequences. At the N-terminus, the iridoviral eIF-2alpha shows significant homology to the N-termini of cellular initiation factor 2-alpha of various species, to full-length poxviral eIF-2alpha proteins, and to the S1 domain of ribosomal proteins. Comparison of amino acid sequences of corresponding iridoviral proteins with eIF-2alpha homologous proteins of poxviruses and eukaryotes has revealed a high conservation of motifs. A phylogenetic analysis of eukaryotic eIF-2alpha and poxvirus and iridovirus eIF-2alpha sequences has demonstrated the relationship of these iridoviruses. In order to investigate the role of the eIF-2alpha equivalent, respective genes have been expressed in prokaryotic and eukaryotic (insect, fish and chicken cell) systems. The iridoviral eIF-2alpha protein has a molecular weight of 31 kDa and is cytoplasmic. The cellular and viral protein synthesis of iridoviruses is probably regulated by a mechanism similar to that of Vaccinia virus. Frog-virus 3, the type species of the genus ranavirus of Iridoviridae, has a unique translational efficiency and, moreover, down-regulates the cellular protein synthesis of infected cells. PMID:11778703

Essbauer, S; Bremont, M; Ahne, W

2001-12-01

59

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

2013-09-01

60

Viral Capsid Is a Pathogen-Associated Molecular Pattern in Adenovirus Keratitis  

PubMed Central

Human adenovirus (HAdV) infection of the human eye, in particular serotypes 8, 19 and 37, induces the formation of corneal subepithelial leukocytic infiltrates. Using a unique mouse model of adenovirus keratitis, we studied the role of various virus-associated molecular patterns in subsequent innate immune responses of resident corneal cells to HAdV-37 infection. We found that neither viral DNA, viral gene expression, or viral replication was necessary for the development of keratitis. In contrast, empty viral capsid induced keratitis and a chemokine profile similar to intact virus. Transfected viral DNA did not induce leukocyte infiltration despite CCL2 expression similar to levels in virus infected corneas. Mice without toll-like receptor 9 (Tlr9) signaling developed clinical keratitis upon HAdV-37 infection similar to wild type mice, although the absolute numbers of activated monocytes in the cornea were less in Tlr9?/? mice. Virus induced leukocytic infiltrates and chemokine expression in mouse cornea could be blocked by treatment with a peptide containing arginine glycine aspartic acid (RGD). These results demonstrate that adenovirus infection of the cornea induces chemokine expression and subsequent infiltration by leukocytes principally through RGD contact between viral capsid and the host cell, possibly through direct interaction between the viral capsid penton base and host cell integrins.

Chintakuntlawar, Ashish V.; Zhou, Xiaohong; Rajaiya, Jaya; Chodosh, James

2010-01-01

61

Different incubation temperatures affect viral polymerase activity and yields of low-pathogenic avian influenza viruses in embryonated chicken eggs  

Microsoft Academic Search

Various incubation conditions (35°C–38°C, 2–7 days) have been used in surveillance studies of the prevalence of avian influenza\\u000a viruses in wild birds. Here, we studied viral polymerase activity and virus growth kinetics of low-pathogenic avian influenza\\u000a viruses (LPAIVs) isolated from field samples [A\\/duck\\/Hong Kong\\/365\\/1978 (H4N6) and A\\/duck\\/Nanchang\\/2–0480\\/2000 (H9N2)] during\\u000a incubation at different temperatures (35°C, 37°C, and 39°C) in the allantoic cavity

Victoria Lang; Henju Marjuki; Scott L. Krauss; Richard J. Webby; Robert G. Webster

2011-01-01

62

Plant viral synergism: the potyviral genome encodes a broad-range pathogenicity enhancer that transactivates replication of heterologous viruses.  

PubMed Central

Synergistic viral diseases of higher plants are caused by the interaction of two independent viruses in the same host and are characterized by dramatic increases in symptoms and in accumulation of one of the coinfecting viruses. In potato virus X (PVX)/potyviral synergism, increased pathogenicity and accumulation of PVX are mediated by the expression of potyviral 5' proximal sequences encoding P1, the helper component proteinase (HC-Pro), and a fraction of P3. Here, we report that the same potyviral sequence (termed P1/HC-Pro) enhances the pathogenicity and accumulation of two other heterologous viruses: cucumber mosaic virus and tobacco mosaic virus. In the case of PVX-potyviral synergism, we show that the expression of the HC-Pro gene product, but not the RNA sequence itself, is sufficient to induce the increase in PVX pathogenicity and that both P1 and P3 coding sequences are dispensable for this aspect of the synergistic interaction. In protoplasts, expression of the potyviral P1/HC-Pro region prolongs the accumulation of PVX (-) strand RNA and transactivates expression of a reporter gene from a PVX subgenomic promoter. Unlike the synergistic enhancement of PVX pathogenicity, which requires only expression of HC-Pro, the enhancement of PVX (-) strand RNA accumulation in protoplasts is significantly greater when the entire P1/HC-Pro sequence is expressed. These results indicate that the potyviral P1/HC-Pro region affects a step in disease development that is common to a broad range of virus infections and suggest a mechanism involving transactivation of viral replication.

Pruss, G; Ge, X; Shi, X M; Carrington, J C; Bowman Vance, V

1997-01-01

63

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

64

Coinfection of tick cell lines has variable effects on replication of intracellular bacterial and viral pathogens.  

PubMed

Ticks transmit various human and animal microbial pathogens and may harbour more than one pathogen simultaneously. Both viruses and bacteria can trigger, and may subsequently suppress, vertebrate host and arthropod vector anti-microbial responses. Microbial coinfection of ticks could lead to an advantage or disadvantage for one or more of the microorganisms. In this preliminary study, cell lines derived from the ticks Ixodes scapularis and Ixodes ricinus were infected sequentially with 2 arthropod-borne pathogens, Borrelia burgdorferi s.s., Ehrlichia ruminantium, or Semliki Forest virus (SFV), and the effect of coinfection on the replication of these pathogens was measured. Prior infection of tick cell cultures with the spirochaete B. burgdorferi enhanced subsequent replication of the rickettsial pathogen E. ruminantium whereas addition of spirochaetes to cells infected with E. ruminantium had no effect on growth of the latter. Both prior and subsequent presence of B. burgdorferi also had a positive effect on SFV replication. Presence of E. ruminantium or SFV had no measurable effect on B. burgdorferi growth. In tick cells infected first with E. ruminantium and then with SFV, virus replication was significantly higher across all time points measured (24, 48, 72h post infection), while presence of the virus had no detectable effect on bacterial growth. When cells were infected first with SFV and then with E. ruminantium, there was no effect on replication of either pathogen. The results of this preliminary study indicate that interplay does occur between different pathogens during infection of tick cells. Further study is needed to determine if this results from direct pathogen-pathogen interaction or from effects on host cell defences, and to determine if these observations also apply in vivo in ticks. If presence of one pathogen in the tick vector results in increased replication of another, this could have implications for disease transmission and incidence. PMID:24685441

Moniuszko, Anna; Rückert, Claudia; Alberdi, M Pilar; Barry, Gerald; Stevenson, Brian; Fazakerley, John K; Kohl, Alain; Bell-Sakyi, Lesley

2014-06-01

65

Coinfection of tick cell lines has variable effects on replication of intracellular bacterial and viral pathogens  

PubMed Central

Ticks transmit various human and animal microbial pathogens and may harbour more than one pathogen simultaneously. Both viruses and bacteria can trigger, and may subsequently suppress, vertebrate host and arthropod vector anti-microbial responses. Microbial coinfection of ticks could lead to an advantage or disadvantage for one or more of the microorganisms. In this preliminary study, cell lines derived from the ticks Ixodes scapularis and Ixodes ricinus were infected sequentially with 2 arthropod-borne pathogens, Borrelia burgdorferi s.s., Ehrlichia ruminantium, or Semliki Forest virus (SFV), and the effect of coinfection on the replication of these pathogens was measured. Prior infection of tick cell cultures with the spirochaete B. burgdorferi enhanced subsequent replication of the rickettsial pathogen E. ruminantium whereas addition of spirochaetes to cells infected with E. ruminantium had no effect on growth of the latter. Both prior and subsequent presence of B. burgdorferi also had a positive effect on SFV replication. Presence of E. ruminantium or SFV had no measurable effect on B. burgdorferi growth. In tick cells infected first with E. ruminantium and then with SFV, virus replication was significantly higher across all time points measured (24, 48, 72 h post infection), while presence of the virus had no detectable effect on bacterial growth. When cells were infected first with SFV and then with E. ruminantium, there was no effect on replication of either pathogen. The results of this preliminary study indicate that interplay does occur between different pathogens during infection of tick cells. Further study is needed to determine if this results from direct pathogen–pathogen interaction or from effects on host cell defences, and to determine if these observations also apply in vivo in ticks. If presence of one pathogen in the tick vector results in increased replication of another, this could have implications for disease transmission and incidence.

Moniuszko, Anna; Ruckert, Claudia; Alberdi, M. Pilar; Barry, Gerald; Stevenson, Brian; Fazakerley, John K.; Kohl, Alain; Bell-Sakyi, Lesley

2014-01-01

66

Phylogenetic concordance analysis shows an emerging pathogen is novel and endemic  

Microsoft Academic Search

Distinguishing whether pathogens are novel or endemic is critical for controlling emerging infectious diseases, an increasing threat to wildlife and human health. To test the endemic vs. novel pathogen hypothesis, we present a unique analysis of intraspecific host-pathogen phylogenetic concordance of tiger salamanders and an emerging Ranavirus throughout Western North America. There is significant non-concordance of host and virus gene

Andrew Storfer; Michael E. Alfaro; Benjamin J. Ridenhour; James K. Jancovich; Stephen G. Mech; Matthew J. Parris; James P. Collins

2007-01-01

67

Different incubation temperatures affect viral polymerase activity and yields of low-pathogenic avian influenza viruses in embryonated chicken eggs  

PubMed Central

Various incubation conditions (35°C–38°C, 2d–7d) have been used in surveillance studies of the prevalence of avian influenza viruses in wild birds. Here, we studied viral polymerase activity and virus growth kinetics of low-pathogenic avian influenza viruses (LPAIVs) isolated from field samples [A/duck/Hong Kong/365/1978 (H4N6) and A/duck/Nanchang/-0480/2000 (H9N2)] during incubation at different temperatures (35°C, 37°C, and 39°C) in the allantoic cavity of 10-day-old embryonated chicken eggs (ECE). The higher incubation temperatures (37°C and 39°C) significantly promoted virus growth which is most likely as a result of greater viral polymerase activity (20%–60%) than that observed at 35°C and as much as 100% greater virus yield (as measured by hemagglutination assay) 2 days after inoculation. Our findings revealed that the optimal activity of viral polymerase complex resulting in highest yield of LPAIV field isolates could be obtained by incubation for 2 days in ECE at 37°C and 39°C.

Lang, Victoria; Marjuki, Henju; Krauss, Scott L.; Webby, Richard J.; Webster, Robert G.

2013-01-01

68

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

69

Mutations in the Cytoplasmic Domain of the Newcastle Disease Virus Fusion Protein Confer Hyperfusogenic Phenotypes Modulating Viral Replication and Pathogenicity  

PubMed Central

The Newcastle disease virus (NDV) fusion protein (F) mediates fusion of viral and host cell membranes and is a major determinant of NDV pathogenicity. In the present study, we demonstrate the effects of functional properties of F cytoplasmic tail (CT) amino acids on virus replication and pathogenesis. Out of a series of C-terminal deletions in the CT, we were able to rescue mutant viruses lacking two or four residues (r?2 and r?4). We further rescued viral mutants with individual amino acid substitutions at each of these four terminal residues (rM553A, rK552A, rT551A, and rT550A). In addition, the NDV F CT has two conserved tyrosine residues (Y524 and Y527) and a dileucine motif (LL536-537). In other paramyxoviruses, these residues were shown to affect fusion activity and are central elements in basolateral targeting. The deletion of 2 and 4 CT amino acids and single tyrosine substitution resulted in hyperfusogenic phenotypes and increased viral replication and pathogenesis. We further found that in rY524A and rY527A viruses, disruption of the targeting signals did not reduce the expression on the apical or basolateral surface in polarized Madin-Darby canine kidney cells, whereas in double tyrosine mutant, it was reduced on both the apical and basolateral surfaces. Interestingly, in rL536A and rL537A mutants, the F protein expression was more on the apical than on the basolateral surface, and this effect was more pronounced in the rL537A mutant. We conclude that these wild-type residues in the NDV F CT have an effect on regulating F protein biological functions and thus modulating viral replication and pathogenesis.

Samal, Sweety; Khattar, Sunil K.; Paldurai, Anandan; Palaniyandi, Senthilkumar; Zhu, Xiaoping; Collins, Peter L.

2013-01-01

70

A single amino acid mutation, R42A, in the Newcastle disease virus matrix protein abrogates its nuclear localization and attenuates viral replication and pathogenicity.  

PubMed

The Newcastle disease virus (NDV) matrix (M) protein is a highly basic and nucleocytoplasmic shuttling viral protein. Previous study has demonstrated that the N-terminal 100 aa of NDV M protein are somewhat acidic overall, but the remainder of the polypeptide is strongly basic. In this study, we investigated the role of the N-terminal basic residues in the subcellular localization of M protein and in the replication and pathogenicity of NDV. We found that mutation of the basic residue arginine (R) to alanine (A) at position 42 disrupted M's nuclear localization. Moreover, a recombinant virus with R42A mutation in the M protein reduced viral replication in DF-1 cells and attenuated the virulence and pathogenicity of the virus in chickens. This is the first report to show that a basic residue mutation in the NDV M protein abrogates its nuclear localization and attenuates viral replication and pathogenicity. PMID:24603525

Duan, Zhiqiang; Li, Juan; Zhu, Jie; Chen, Jian; Xu, Haixu; Wang, Yuyang; Liu, Huimou; Hu, Shunlin; Liu, Xiufan

2014-05-01

71

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

72

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

73

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...

74

Intact Dendritic Cell Pathogen-Recognition Receptor Functions Associate with Chronic Hepatitis C Treatment-Induced Viral Clearance  

PubMed Central

Although studies have addressed the exhaustion of the host's immune response to HCV and its role in treatment, there is little information about the possible contribution of innate immunity to treatment-induced clearance. We hypothesized that because intact myeloid dendritic cell (MDC) pathogen sensing functions are associated with improved HCV-specific CD8+ T cell functionality in some chronically infected patients, it might enhance HCV clearance rate under standard interferon therapy. To investigate this hypothesis, TLR-induced MDC activation and HCV-specific CD8+ T cell response quality were monitored longitudinally at the single-cell level using polychromatic flow cytometry in chronically infected patients undergoing interferon therapy. We correlated the immunological, biochemical and virological data with response to treatment. We demonstrate that the clinical efficacy of interferon-induced viral clearance is influenced by the extent to which HCV inhibits MDC functions before treatment, rather than solely on a breakdown of the extrinsic T cell immunosuppressive environment. Thus, viral inhibition of MDC functions before treatment emerges as a co-determining factor in the clinical efficacy of interferon therapy during chronic HCV infection.

Rodrigue-Gervais, Ian Gael; Willems, Bernard; Lamarre, Daniel

2014-01-01

75

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

76

Plant responses against invasive nucleic acids: RNA silencing and its suppression by plant viral pathogens  

PubMed Central

RNA silencing is a common strategy shared by eukaryotic organisms to regulate gene expression, and also operates as a defense mechanism against invasive nucleic acids such as viral transcripts. The silencing pathway is quite sophisticated in higher eukaryotes but the distinct steps and nature of effector complexes vary between and even within species. To counteract this defense mechanism viruses have evolved the ability to encode proteins that suppress silencing to protect their genomes from degradation. This review focuses on our current understanding of how individual components of the plant RNA silencing mechanism are directed against viruses, and how in turn virus-encoded suppressors target one or more key events in the silencing cascade.

Alvarado, Veria; Scholthof, Herman B.

2010-01-01

77

Viral and host factors that contribute to pathogenicity of enterovirus 71.  

PubMed

The single-stranded RNA virus enterovirus 71 (EV71), which belongs to the Picornaviridae family, has caused epidemics worldwide, particularly in the Asia-Pacific region. Most EV71 infections result in mild clinical symptoms, including herpangina and hand, foot and mouth disease. However, serious pathological complications have also been reported, especially for young children. The mechanisms of EV71 disease progression remain unclear. The pathogenesis of adverse clinical outcomes may relate to many factors, including cell tropism, cell death and host immune responses. This article reviews the recent advances in the identification of factors determining EV71 cell tropism, the associated mechanisms of viral infection-induced cell death and the interplay between EV71 and immunity. PMID:22439724

Huang, Hsing-I; Weng, Kuo-Feng; Shih, Shin-Ru

2012-04-01

78

Ranavirus-associated mass mortality in wild amphibians, the Netherlands, 2010: a first report.  

PubMed

In 2010, a mass die-off of over 1000 wild water frogs (Pelophylax spp.) and at least 10 common newts (Lissotriton vulgaris) occurred in a pond in The Netherlands. Haemorrhagic disease with hepatomegaly and splenomegaly was evident. Microscopically, multiple organs presented cells with multifocal intracytoplasmic inclusion bodies, in which ranavirus-like particles were demonstrated ultrastructurally. All specimens examined tested positive for ranavirus by PCR. The sequence obtained showed a 100% identity with the one deposited for common midwife toad virus (CMTV). This is the first report of ranavirus-associated mortality in wild amphibian populations in The Netherlands. It is also the first time CMTV or a CMTV-like virus has been reported in these two species in the adult stage and outside of Spain. PMID:21955440

Kik, Marja; Martel, An; Sluijs, Annemarieke Spitzen-van der; Pasmans, Frank; Wohlsein, Peter; Gröne, Andrea; Rijks, Jolianne M

2011-11-01

79

Pathogenic poxviruses reveal viral strategies to exploit the ErbB signaling network.  

PubMed Central

Virulence of poxviruses, the causative agents of smallpox, depends on virus-encoded growth factors related to the mammalian epidermal growth factor (EGF). Here we report that the growth factors of Shope fibroma virus, Myxoma virus and vaccinia virus (SFGF, MGF and VGF) display unique patterns of specificity to ErbB receptor tyrosine kinases; whereas SFGF is a broad-specificity ligand, VGF binds primarily to ErbB-1 homodimers, and the exclusive receptor for MGF is a heterodimer comprised of ErbB-2 and ErbB-3. In spite of 10- to 1000-fold lower binding affinity to their respective receptors, the viral ligands are mitogenically equivalent or even more potent than their mammalian counterparts. This remarkable enhancement of cell growth is due to attenuation of receptor degradation and ubiquitination, which leads to sustained signal transduction. Our results imply that signal potentiation and precise targeting to specific receptor combinations contribute to cell transformation at sites of poxvirus infection, and they underscore the importance of the often ignored low-affinity ligand-receptor interactions.

Tzahar, E; Moyer, J D; Waterman, H; Barbacci, E G; Bao, J; Levkowitz, G; Shelly, M; Strano, S; Pinkas-Kramarski, R; Pierce, J H; Andrews, G C; Yarden, Y

1998-01-01

80

CD8 T Cell Memory to a Viral Pathogen Requires Trans Cosignaling between HVEM and BTLA  

PubMed Central

Defining the molecular interactions required to program activated CD8 T cells to survive and become memory cells may allow us to understand how to augment anti-viral immunity. HVEM (herpes virus entry mediator) is a member of the tumor necrosis factor receptor (TNFR) family that interacts with ligands in the TNF family, LIGHT and Lymphotoxin-?, and in the Ig family, B and T lymphocyte attenuator (BTLA) and CD160. The Ig family members initiate inhibitory signaling when engaged with HVEM, but may also activate survival gene expression. Using a model of vaccinia virus infection, we made the unexpected finding that deficiency in HVEM or BTLA profoundly impaired effector CD8 T cell survival and development of protective immune memory. Mixed adoptive transfer experiments indicated that BTLA expressed in CD8?+ dendritic cells functions as a trans-activating ligand that delivers positive co-signals through HVEM expressed in T cells. Our data demonstrate a critical role of HVEM-BTLA bidirectional cosignaling system in antiviral defenses by driving the differentiation of memory CD8 T cells.

Flynn, Rachel; Hutchinson, Tarun; Murphy, Kenneth M.; Ware, Carl F.; Croft, Michael; Salek-Ardakani, Shahram

2013-01-01

81

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

82

Interferometric biosensing platform for multiplexed digital detection of viral pathogens and biomarkers  

NASA Astrophysics Data System (ADS)

Label-free optical biosensors have been established as proven tools for monitoring specific biomolecular interactions. However, compact and robust embodiments of such instruments have yet to be introduced in order to provide sensitive, quantitative, and high-throughput biosensing for low-cost research and clinical applications. Here we present the interferometric reflectance-imaging sensor (IRIS). IRIS allows sensitive label free analysis using an inexpensive and durable multi-color LED illumination source on a silicon based surface. IRIS monitors biomolecular interaction through measurement of biomass addition to the sensor's surface. We demonstrate the capability of this system to dynamically monitor antigen---antibody interactions with a noise floor of 5.2 pg/mm 2 and DNA single mismatch detection under isothermal melting conditions in an array format. Ensemble detection of binding events using IRIS did not provide the sensitivity needed for detection of infectious disease and biomarkers at clinically relevant concentrations. Therefore, a new approach was adapted to the IRIS platform that allowed the detection and identification of individual nanoparticles on the sensor's surface. The new detection method was termed single-particle IRIS (SP-IRIS). We developed two detection modalities for SP-IRIS. The first modality is when the target is a nanoparticle such as a virus. We verified that SP-IRIS can accurately detect and size individual viral particles. Then we demonstrated that single nanoparticle counting and sizing methodology on SP-IRIS leads to a specific and sensitive virus sensor that can be multiplexed. Finally, we developed an assay for the detection of Ebola and Marburg. A detection limit of 3 x 103 PFU/ml was demonstrated for vesicular stomatitis virus (VSV) pseudotyped with Ebola or Marburg virus glycoprotein. We have demonstrated that virus detection can be done in human whole blood directly without the need for sample preparation. The second modality of SP-IRIS we developed was single molecule counting of biomarkers utilizing a sandwich assay with detection probes labeled with gold nanoparticles. We demonstrated the use of single molecule counting in a nucleic acid assay for melanoma biomarker detection. We showed that a single molecule counting assay can lead to detection limits in the attomolar range. The improved sensitivity of IRIS utilizing single nanoparticle detection holds promise for a simple and low-cost technology for rapid virus detection and multiplexed molecular screening for clinical applications.

Daaboul, George

83

A two-tube multiplex reverse transcription PCR assay for simultaneous detection of viral and bacterial pathogens of infectious diarrhea.  

PubMed

Diarrhea caused by viral and bacterial infections is a major health problem in developing countries. The purpose of this study is to develop a two-tube multiplex PCR assay using automatic electrophoresis for simultaneous detection of 13 diarrhea-causative viruses or bacteria, with an intended application in provincial Centers for Diseases Control and Prevention, China. The assay was designed to detect rotavirus A, norovirus genogroups GI and GII, human astrovirus, enteric adenoviruses, and human bocavirus (tube 1), and Salmonella, Vibrio parahaemolyticus, diarrheagenic Escherichia coli, Campylobacter jejuni, Shigella, Yersinia, and Vibrio cholera (tube 2). The analytical specificity was examined with positive controls for each pathogen. The analytical sensitivity was evaluated by performing the assay on serial tenfold dilutions of in vitro transcribed RNA, recombinant plasmids, or bacterial culture. A total of 122 stool samples were tested by this two-tube assay and the results were compared with those obtained from reference methods. The two-tube assay achieved a sensitivity of 20-200 copies for a single virus and 10(2)-10(3)?CFU/mL for bacteria. The clinical performance demonstrated that the two-tube assay had comparable sensitivity and specificity to those of reference methods. In conclusion, the two-tube assay is a rapid, cost-effective, sensitive, specific, and high throughput method for the simultaneous detection of enteric bacteria and virus. PMID:24711998

Wang, Ji; Xu, Ziqian; Niu, Peihua; Zhang, Chen; Zhang, Jingyun; Guan, Li; Kan, Biao; Duan, Zhaojun; Ma, Xuejun

2014-01-01

84

A Two-Tube Multiplex Reverse Transcription PCR Assay for Simultaneous Detection of Viral and Bacterial Pathogens of Infectious Diarrhea  

PubMed Central

Diarrhea caused by viral and bacterial infections is a major health problem in developing countries. The purpose of this study is to develop a two-tube multiplex PCR assay using automatic electrophoresis for simultaneous detection of 13 diarrhea-causative viruses or bacteria, with an intended application in provincial Centers for Diseases Control and Prevention, China. The assay was designed to detect rotavirus A, norovirus genogroups GI and GII, human astrovirus, enteric adenoviruses, and human bocavirus (tube 1), and Salmonella, Vibrio parahaemolyticus, diarrheagenic Escherichia coli, Campylobacter jejuni, Shigella, Yersinia, and Vibrio cholera (tube 2). The analytical specificity was examined with positive controls for each pathogen. The analytical sensitivity was evaluated by performing the assay on serial tenfold dilutions of in vitro transcribed RNA, recombinant plasmids, or bacterial culture. A total of 122 stool samples were tested by this two-tube assay and the results were compared with those obtained from reference methods. The two-tube assay achieved a sensitivity of 20–200 copies for a single virus and 102-103?CFU/mL for bacteria. The clinical performance demonstrated that the two-tube assay had comparable sensitivity and specificity to those of reference methods. In conclusion, the two-tube assay is a rapid, cost-effective, sensitive, specific, and high throughput method for the simultaneous detection of enteric bacteria and virus.

Wang, Ji; Xu, Ziqian; Niu, Peihua; Zhang, Chen; Zhang, Jingyun; Guan, Li; Kan, Biao; Duan, Zhaojun

2014-01-01

85

Differences in highly pathogenic avian influenza viral pathogenesis and associated early inflammatory response in chickens and ducks.  

PubMed

We studied the immunological responses in the lung, brain and spleen of ducks and chickens within the first 7 days after infection with H7N1 highly pathogenic avian influenza (HPAI). Infection with HPAI caused significant morbidity and mortality in chickens, while in ducks the infection was asymptomatic. The HPAI viral mRNA load was higher in all investigated tissues of chickens compared with duck tissues. In the lung, brain and spleen of HPAI-infected chickens, a high, but delayed, pro-inflammatory response of IL-6 and IL-1? mRNA was induced, including up-regulation of IFN-?, IFN-?, TLR3 and MDA-5 mRNA from 1 day post infection (p.i.). Whereas in ducks already at 8 h p.i., a quicker but lower response was found for IL-6, IL-1? and iNOS mRNA followed by a delayed activation of TLR7, RIG-I, MDA5 and IFN-? mRNA response. Virus-infected areas in the lung of chickens co-localized with KUL-01? (macrophages, dendritic cells), CD4?, and CD8?? cells, during the first day after infection. However, only KUL-01? cells co-localized with the virus after 1 day p.i. In ducks, CVI-ChNL-68.1? (macrophage-like cells), CD4? and CD8?? cells and apoptosis co-localized with the virus within 8 h p.i. Apoptosis was detected in the brain and lung of HPAI-infected chickens after 2 days p.i. and apoptotic cells co-localized with virus-infected areas. In conclusion, excessive delayed cytokine inflammatory responses but inadequate cellular immune responses may contribute to pathogenesis in chickens, while ducks initiate a fast lower cytokine response followed by the activation of major pattern recognition receptors (TLR7, RIG-I, MDA5) and a persistent cellular response. PMID:23782222

Cornelissen, J B W J; Vervelde, L; Post, J; Rebel, J M J

2013-08-01

86

NS Reassortment of an H7-Type Highly Pathogenic Avian Influenza Virus Affects Its Propagation by Altering the Regulation of Viral RNA Production and Antiviral Host Response? †  

PubMed Central

Highly pathogenic avian influenza viruses (HPAIV) with reassorted NS segments from H5- and H7-type avian virus strains placed in the genetic background of the A/FPV/Rostock/34 HPAIV (FPV; H7N1) were generated by reverse genetics. Virological characterizations demonstrated that the growth kinetics of the reassortant viruses differed from that of wild-type (wt) FPV and depended on whether cells were of mammalian or avian origin. Surprisingly, molecular analysis revealed that the different reassortant NS segments were not only responsible for alterations in the antiviral host response but also affected viral genome replication and transcription as well as nuclear ribonucleoprotein (RNP) export. RNP reconstitution experiments demonstrated that the effects on accumulation levels of viral RNA species were dependent on the specific NS segment as well as on the genetic background of the RNA-dependent RNA polymerase (RdRp). Beta interferon (IFN-?) expression and the induction of apoptosis were found to be inversely correlated with the magnitude of viral growth, while the NS allele, virus subtype, and nonstructural protein NS1 expression levels showed no correlation. Thus, these results demonstrate that the origin of the NS segment can have a dramatic effect on the replication efficiency and host range of HPAIV. Overall, our data suggest that the propagation of NS reassortant influenza viruses is affected at multiple steps of the viral life cycle as a result of the different effects of the NS1 protein on multiple viral and host functions.

Wang, Zhongfang; Robb, Nicole C.; Lenz, Eva; Wolff, Thorsten; Fodor, Ervin; Pleschka, Stephan

2010-01-01

87

1918 Influenza Virus Hemagglutinin (HA) and the Viral RNA Polymerase Complex Enhance Viral Pathogenicity, but Only HA Induces Aberrant Host Responses in Mice  

PubMed Central

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.

Tisoncik-Go, Jennifer; Tchitchek, Nicolas; Watanabe, Shinji; Benecke, Arndt G.; Katze, Michael G.

2013-01-01

88

The 18S rDNA sequence of Synchytrium endobioticum and its utility in microarrays for the simultaneous detection of fungal and viral pathogens of potato.  

PubMed

Resting spores extracted from wart (Synchytrium endobioticum)-infected potato tubers were used for DNA extraction and amplification of 18S rDNA. Analysis of the cloned, sequenced fragment revealed high similarity to members of the Chytridiomycota. Using this information, specific oligonucleotide probes were designed and arrayed onto glass slides for detection of the pathogen. Viral sequence information available in the databank was retrieved, or new viral sequences were generated, and used to design probes for specific detection of important quarantine viruses of potato. To determine the sensitivity and specificity of the oligonucleotide probes, total RNA from infected plants was reverse transcribed, labelled with Cyanine 5, and hybridised with the microarray. A significant number of the oligonucleotide probes exhibited high specificity to S. endobioticum, Andean potato latent virus, Andean potato mottle virus, Potato black ringspot virus, and Potato spindle tuber viroid. Hybridisation signals of sub-arrays within slides were reproducible (r = 0.79) with a high correlation coefficient of hybridisation repetitions (0.73). Our results demonstrate the potential of microarray-based hybridisation for identification of multiple pathogen targets, which will find application in quarantine laboratories, where parallel testing for diverse pathogens is essential. PMID:15800764

Abdullahi, Ismail; Koerbler, Marianne; Stachewicz, Hans; Winter, Stephan

2005-08-01

89

Experimentally infected domestic ducks show efficient transmission of Indonesian H5N1 highly pathogenic avian influenza virus, but lack persistent viral shedding.  

PubMed

Ducks are important maintenance hosts for avian influenza, including H5N1 highly pathogenic avian influenza viruses. A previous study indicated that persistence of H5N1 viruses in ducks after the development of humoral immunity may drive viral evolution following immune selection. As H5N1 HPAI is endemic in Indonesia, this mechanism may be important in understanding H5N1 evolution in that region. To determine the capability of domestic ducks to maintain prolonged shedding of Indonesian clade 2.1 H5N1 virus, two groups of Pekin ducks were inoculated through the eyes, nostrils and oropharynx and viral shedding and transmission investigated. Inoculated ducks (n?=?15), which were mostly asymptomatic, shed infectious virus from the oral route from 1 to 8 days post inoculation, and from the cloacal route from 2-8 dpi. Viral ribonucleic acid was detected from 1-15 days post inoculation from the oral route and 1-24 days post inoculation from the cloacal route (cycle threshold <40). Most ducks seroconverted in a range of serological tests by 15 days post inoculation. Virus was efficiently transmitted during acute infection (5 inoculation-infected to all 5 contact ducks). However, no evidence for transmission, as determined by seroconversion and viral shedding, was found between an inoculation-infected group (n?=?10) and contact ducks (n?=?9) when the two groups only had contact after 10 days post inoculation. Clinical disease was more frequent and more severe in contact-infected (2 of 5) than inoculation-infected ducks (1 of 15). We conclude that Indonesian clade 2.1 H5N1 highly pathogenic avian influenza virus does not persist in individual ducks after acute infection. PMID:24392085

Wibawa, Hendra; Bingham, John; Nuradji, Harimurti; Lowther, Sue; Payne, Jean; Harper, Jenni; Junaidi, Akhmad; Middleton, Deborah; Meers, Joanne

2014-01-01

90

A reverse genetics system for the Great Lakes strain of viral hemorrhagic septicemia virus: the NV gene is required for pathogenicity  

USGS Publications Warehouse

Viral hemorrhagic septicemia virus (VHSV), belonging to the genus Novirhabdovirus in the family of Rhabdoviridae, causes a highly contagious disease of fresh and saltwater fish worldwide. Recently, a novel genotype of VHSV, designated IVb, has invaded the Great Lakes in North America, causing large-scale epidemics in wild fish. An efficient reverse genetics system was developed to generate a recombinant VHSV of genotype IVb from cloned cDNA. The recombinant VHSV (rVHSV) was comparable to the parental wild-type strain both in vitro and in vivo, causing high mortality in yellow perch (Perca flavescens). A modified recombinant VHSV was generated in which the NV gene was substituted with an enhanced green fluorescent protein gene (rVHSV-?NV-EGFP), and another recombinant was made by inserting the EGFP gene into the full-length viral clone between the P and M genes (rVHSV-EGFP). The in vitro replication kinetics of rVHSV-EGFP was similar to rVHSV; however, the rVHSV-?NV-EGFP grew 2 logs lower. In yellow perch challenges, wtVHSV and rVHSV induced 82-100% cumulative per cent mortality (CPM), respectively, whereas rVHSV-EGFP produced 62% CPM and rVHSV-?NV-EGFP caused only 15% CPM. No reversion of mutation was detected in the recovered viruses and the recombinant viruses stably maintained the foreign gene after several passages. These results indicate that the NV gene of VHSV is not essential for viral replication in vitro and in vivo, but it plays an important role in viral replication efficiency and pathogenicity. This system will facilitate studies of VHSV replication, virulence, and production of viral vectored vaccines.

Ammayappan, Arun; Kurath, Gael; Thompson, Tarin M.; Vakharia, Vikram N.

2011-01-01

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

Concurrent ranavirus and Batrachochytrium dendrobatidis infection in captive frogs (Phyllobates and Dendrobates species), The Netherlands, 2012: a first report.  

PubMed

A ranavirus infection with concurrent Batrachochytrium dendrobatidis infection and mortality in captive Phyllobates and Dendrobates species is reported. Greyish skin with hepato- and reno-megaly were evident. Microscopically, Batrachochytrium dendrobatidis was present in the stratum corneum of the hyperkeratotic skin. Intracytoplasmic inclusion bodies were present in erythrocytes and multiple organs. All samples examined tested positive using PCR for the major capsid protein (MCP) gene of ranavirus and the ITS-1-5.8S region of B. dendrobatidis. The sequence obtained showed a 99% identity with the deposited sequence of the MCP gene of the common midwife toad virus (CMTV). This is the first report of mortality in captivity in poison dart frogs caused by a ranavirus, CMTV or like virus, and Batrachochytrium dendrobatidis infection. PMID:23102620

Kik, Marja; Stege, Marisca; Boonyarittichaikij, Roschong; van Asten, Alphons

2012-11-01

93

Mutagenesis of phospholipase D defines a superfamily including a trans-Golgi viral protein required for poxvirus pathogenicity.  

PubMed Central

Phospholipase D (PLD) genes are members of a superfamily that is defined by several highly conserved motifs. PLD in mammals has been proposed to play a role in membrane vesicular trafficking and signal transduction. Using site-directed mutagenesis, 25 point mutants have been made in human PLD1 (hPLD1) and characterized. We find that a motif (HxKxxxxD) and a serine/threonine conserved in all members of the PLD superfamily are critical for PLD biochemical activity, suggesting a possible catalytic mechanism. Functional analysis of catalytically inactive point mutants for yeast PLD demonstrates that the meiotic phenotype ensuing from PLD deficiency in yeast derives from a loss of enzymatic activity. Finally, mutation of an HxKxxxxD motif found in a vaccinia viral protein expressed in the Golgi complex results in loss of efficient vaccinia virus cell-to-cell spreading, implicating the viral protein as a member of the superfamily and suggesting that it encodes a lipid modifying or binding activity. The results suggest that vaccinia virus and hPLD1 may act through analogous mechanisms to effect viral cellular egress and vesicular trafficking, respectively.

Sung, T C; Roper, R L; Zhang, Y; Rudge, S A; Temel, R; Hammond, S M; Morris, A J; Moss, B; Engebrecht, J; Frohman, M A

1997-01-01

94

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

95

Enhanced control of pathogenic Simian immunodeficiency virus SIVmac239 replication in macaques immunized with an interleukin-12 plasmid and a DNA prime-viral vector boost vaccine regimen.  

PubMed

DNA priming has previously been shown to elicit augmented immune responses when administered by electroporation (EP) or codelivered with a plasmid encoding interleukin-12 (pIL-12). We hypothesized that the efficacy of a DNA prime and recombinant adenovirus 5 boost vaccination regimen (DNA/rAd5) would be improved when incorporating these vaccination strategies into the DNA priming phase, as determined by pathogenic simian immunodeficiency virus SIVmac239 challenge outcome. The whole SIVmac239 proteome was delivered in 5 separate DNA plasmids (pDNA-SIV) by EP with or without pIL-12, followed by boosting 4 months later with corresponding rAd5-SIV vaccine vectors. Remarkably, after repeated low-dose SIVmac239 mucosal challenge, we demonstrate 2.6 and 4.4 log reductions of the median SIV peak and set point viral loads in rhesus macaques (RMs) that received pDNA-SIV by EP with pIL-12 compared to the median peak and set point viral loads in mock-immunized controls (P < 0.01). In 5 out of 6 infected RMs, strong suppression of viremia was observed, with intermittent "blips" in virus replication. In 2 RMs, we could not detect the presence of SIV RNA in tissue and lymph nodes, even after 13 viral challenges. RMs immunized without pIL-12 demonstrated a typical maximum of 1.5 log reduction in virus load. There was no significant difference in the overall magnitude of SIV-specific antibodies or CD8 T-cell responses between groups; however, pDNA delivery by EP with pIL-12 induced a greater magnitude of SIV-specific CD4 T cells that produced multiple cytokines. This vaccine strategy is relevant for existing vaccine candidates entering clinical evaluation, and this model may provide insights into control of retrovirus replication. PMID:21734035

Winstone, Nicola; Wilson, Aaron J; Morrow, Gavin; Boggiano, Cesar; Chiuchiolo, Maria J; Lopez, Mary; Kemelman, Marina; Ginsberg, Arielle A; Mullen, Karl; Coleman, John W; Wu, Chih-Da; Narpala, Sandeep; Ouellette, Ian; Dean, Hansi J; Lin, Feng; Sardesai, Niranjan Y; Cassamasa, Holly; McBride, Dawn; Felber, Barbara K; Pavlakis, George N; Schultz, Alan; Hudgens, Michael G; King, C Richter; Zamb, Timothy J; Parks, Christopher L; McDermott, Adrian B

2011-09-01

96

Enhanced Control of Pathogenic Simian Immunodeficiency Virus SIVmac239 Replication in Macaques Immunized with an Interleukin-12 Plasmid and a DNA Prime-Viral Vector Boost Vaccine Regimen ? §  

PubMed Central

DNA priming has previously been shown to elicit augmented immune responses when administered by electroporation (EP) or codelivered with a plasmid encoding interleukin-12 (pIL-12). We hypothesized that the efficacy of a DNA prime and recombinant adenovirus 5 boost vaccination regimen (DNA/rAd5) would be improved when incorporating these vaccination strategies into the DNA priming phase, as determined by pathogenic simian immunodeficiency virus SIVmac239 challenge outcome. The whole SIVmac239 proteome was delivered in 5 separate DNA plasmids (pDNA-SIV) by EP with or without pIL-12, followed by boosting 4 months later with corresponding rAd5-SIV vaccine vectors. Remarkably, after repeated low-dose SIVmac239 mucosal challenge, we demonstrate 2.6 and 4.4 log reductions of the median SIV peak and set point viral loads in rhesus macaques (RMs) that received pDNA-SIV by EP with pIL-12 compared to the median peak and set point viral loads in mock-immunized controls (P < 0.01). In 5 out of 6 infected RMs, strong suppression of viremia was observed, with intermittent “blips” in virus replication. In 2 RMs, we could not detect the presence of SIV RNA in tissue and lymph nodes, even after 13 viral challenges. RMs immunized without pIL-12 demonstrated a typical maximum of 1.5 log reduction in virus load. There was no significant difference in the overall magnitude of SIV-specific antibodies or CD8 T-cell responses between groups; however, pDNA delivery by EP with pIL-12 induced a greater magnitude of SIV-specific CD4 T cells that produced multiple cytokines. This vaccine strategy is relevant for existing vaccine candidates entering clinical evaluation, and this model may provide insights into control of retrovirus replication.

Winstone, Nicola; Wilson, Aaron J.; Morrow, Gavin; Boggiano, Cesar; Chiuchiolo, Maria J.; Lopez, Mary; Kemelman, Marina; Ginsberg, Arielle A.; Mullen, Karl; Coleman, John W.; Wu, Chih-Da; Narpala, Sandeep; Ouellette, Ian; Dean, Hansi J.; Lin, Feng; Sardesai, Niranjan Y.; Cassamasa, Holly; McBride, Dawn; Felber, Barbara K.; Pavlakis, George N.; Schultz, Alan; Hudgens, Michael G.; King, C. Richter; Zamb, Timothy J.; Parks, Christopher L.; McDermott, Adrian B.

2011-01-01

97

Non?specific reactivity of sera in ELISAs for detecting antibodies to bacterial, viral and mycoplasmal pathogens of poultry  

Microsoft Academic Search

Enzyme?linked immunosorbent assays (ELISAs) were developed for the detection of antibodies to Mycoplasma synoviae, infectious bronchitis virus (IBV) Pasteurella multocida, infectious bursal disease virus (IBDV), reovirus, egg?drop syndrome (EDS) and reticuloendotheliosis virus (REV). Purified antigenic preparations derived from the various pathogens were used to coat microtitre plates. A non?specific factor in some serum samples bound to many of the antigen?coated

B. Roberts; K. Howes

1992-01-01

98

Members of the Arabidopsis HRT/RPP8 family of resistance genes confer resistance to both viral and oomycete pathogens.  

PubMed

Turnip crinkle virus (TCV) inoculation onto TCV-resistant Arabidopsis leads to a hypersensitive response (HR) controlled by the dominant gene HRT. HRT is a member of the class of resistance (R) genes that contain a leucine zipper, a nucleotide binding site, and leucine-rich repeats. The chromosomal position of HRT and its homology to resistance gene RPP8 and two RPP8 homologs indicate that unequal crossing over and gene conversion may have contributed to HRT evolution. RPP8 confers resistance to an oomycete pathogen, Peronospora parasitica. Despite very strong similarities within the HRT/RPP8 family, HRT and RPP8 are specific for the respective pathogens they detect. Hence, the HRT/RPP8 family provides molecular evidence that sequence changes between closely related members of multigene families can generate novel specificities for radically different pathogens. Transgenic plants expressing HRT developed an HR but generally remained susceptible to TCV because of a second gene, RRT, that regulates resistance to TCV. However, several transgenic plants that overexpressed HRT produced micro-HRs or no HR when inoculated with TCV and were resistant to infection. Expression of the TCV coat protein gene in seedlings containing HRT resulted in massive necrosis and death, indicating that the avirulence factor detected by the HRT-encoded protein is the TCV coat protein. PMID:10810142

Cooley, M B; Pathirana, S; Wu, H J; Kachroo, P; Klessig, D F

2000-05-01

99

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

100

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

101

The origin of the PB1 segment of swine influenza A virus subtype H1N2 determines viral pathogenicity in mice.  

PubMed

Swine appear to be a key species in the generation of novel human influenza pandemics. Previous pandemic viruses are postulated to have evolved in swine by reassortment of avian, human, and swine influenza viruses. The human pandemic influenza viruses that emerged in 1957 and 1968 as well as swine viruses circulating since 1998 encode PB1 segments derived from avian influenza viruses. Here we investigate the possible role in viral replication and virulence of the PB1 gene segments present in two swine H1N2 influenza A viruses, A/swine/Sweden/1021/2009(H1N2) (sw 1021) and A/swine/Sweden/9706/2010(H1N2) (sw 9706), where the sw 1021 virus has shown to be more pathogenic in mice. By using reverse genetics, we swapped the PB1 genes of these two viruses. Similar to the sw 9706 virus, chimeric sw 1021 virus carrying the sw 9706 PB1 gene was not virulent in mice. In contrast, replacement of the PB1 gene of the sw 9706 virus by that from sw 1021 virus resulted in increased pathogenicity. Our study demonstrated that differences in virulence of swine influenza virus subtype H1N2 are attributed at least in part to the PB1 segment. PMID:24726997

Metreveli, Giorgi; Gao, Qinshan; Mena, Ignacio; Schmolke, Mirco; Berg, Mikael; Albrecht, Randy A; García-Sastre, Adolfo

2014-08-01

102

Epitope-Specific CD8+ T Cells Play a Differential Pathogenic Role in the Development of a Viral Disease Model for Multiple Sclerosis  

PubMed Central

Theiler's virus-induced demyelinating disease has been extensively investigated as a model for persistent viral infection and multiple sclerosis (MS). However, the role of CD8+ T cells in the development of disease remains unclear. To assess the role of virus-specific CD8+ T cells in the pathogenesis of demyelinating disease, a single amino acid substitution was introduced into the predominant viral epitope (VP3 from residues 159 to 166 [VP3159-166]) and/or a subdominant viral epitope (VP3173-181) of susceptible SJL/J mice by site-directed mutagenesis. The resulting variant viruses (N160V, P179A, and N160V/P179A) failed to induce CD8+ T cell responses to the respective epitopes. Surprisingly, mice infected with N160V or N160V/P179A virus, which lacks CD8+ T cells against VP3159-166, did not develop demyelinating disease, in contrast to wild-type virus or P179A virus lacking VP3173-181-specific CD8+ T cells. Our findings clearly show that the presence of VP3159-166-specific CD8+ T cells, rather than viral persistence itself, is strongly correlated with disease development. VP3173-181-specific CD8+ T cells in the central nervous system (CNS) of these virus-infected mice expressed higher levels of transforming growth factor ?, forkhead box P3, interleukin-22 (IL-22), and IL-17 mRNA but caused minimal cytotoxicity compared to that caused by VP3159-166-specific CD8+ T cells. VP3159-166-specific CD8+ T cells exhibited high functional avidity for gamma interferon production, whereas VP3173-181-specific CD8+ T cells showed low avidity. To our knowledge, this is the first report indicating that the induction of the IL-17-producing CD8+ T cell type is largely epitope specific and that this specificity apparently plays a differential role in the pathogenicity of virus-induced demyelinating disease. These results strongly advocate for the careful consideration of CD8+ T cell-mediated intervention of virus-induced inflammatory diseases.

Myoung, Jinjong; Kang, Hyun Seok; Hou, Wanqiu; Meng, Liping; Dal Canto, Mauro C.

2012-01-01

103

Viral Entry through CXCR4 Is a Pathogenic Factor and Therapeutic Target in Human Immunodeficiency Virus Type 1 Disease  

PubMed Central

The chemokine receptors CCR5 and CXCR4 function as the principal coreceptors for human immunodeficiency virus type 1 (HIV-1). Coreceptor function has also been demonstrated for a variety of related receptors in vitro. The relative contributions of CCR5, CXCR4, and other putative coreceptors to HIV-1 disease in vivo have yet to be defined. In this study, we used sequential primary isolates and recombinant strains of HIV-1 to demonstrate that CXCR4-using (X4) viruses emerging in association with disease progression are highly pathogenic in ex vivo lymphoid tissues compared to CXCR4-independent viruses. Furthermore, synthetic receptor antagonists that specifically block CXCR4-mediated entry dramatically suppressed the depletion of CD4+ T cells by recombinant and clinically derived X4 HIV-1 isolates. Moreover, in vitro specificity for the additional coreceptors CCR3, CCR8, BOB, and Bonzo did not augment cytopathicity or diminish sensitivity toward CXCR4 antagonists in lymphoid tissues. These data provide strong evidence to support the concept that adaptation to CXCR4 specificity in vivo accelerates HIV-1 disease progression. Thus, therapeutic intervention targeting the interaction of HIV-1 gp120 with CXCR4 may be highly valuable for suppressing the pathogenic effects of late-stage viruses.

Schramm, Birgit; Penn, Michael L.; Speck, Roberto F.; Chan, Stephen Y.; De Clercq, Erik; Schols, Dominique; Connor, Ruth I.; Goldsmith, Mark A.

2000-01-01

104

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

105

Association of Increased Pathogenicity of Asian H5N1 Highly Pathogenic Avian Influenza Viruses in Chickens with Highly Efficient Viral Replication Accompanied by Early Destruction of Innate Immune Responses? †  

PubMed Central

The Asian H5N1 highly pathogenic avian influenza (HPAI) viruses have been increasing in pathogenicity in diverse avian species since 1996 and are now widespread in Asian, European, and African countries. To better understand the basis of the increased pathogenicity of recent Asian H5N1 HPAI viruses in chickens, we compared the fevers and mean death times (MDTs) of chickens infected with the Asian H5N1 A/chicken/Yamaguchi/7/04 (CkYM7) strain with those infected with the H5N1 Duck/Yokohama/aq10/03 (DkYK10) strain, using a wireless thermosensor. Asian H5N1 CkYM7 caused peracute death in chickens before fever could be induced, whereas DkYK10 virus induced high fevers and had a long MDT. Real-time PCR analyses of cytokine mRNA expressions showed that CkYM7 quickly induced antiviral and proinflammatory cytokine mRNA expressions at 24 h postinfection (hpi) that suddenly decreased at 32 hpi. In contrast, these cytokine mRNA expressions increased at 24 hpi in the DkYK10 group, but decreased from 48 hpi onward to levels similar to those resulting from infection with the low-pathogenicity H5N2 A/chicken/Ibaraki/1/2004 strain. Sequential titrations of viruses in lungs, spleens, and kidneys demonstrated that CkYM7 replicated rapidly and efficiently in infected chickens and that the viral titers were more than twofold higher than those of DkYK10. CkYM7 preferentially and efficiently replicated in macrophages and vascular endothelial cells, while DkYK10 grew moderately in macrophages. These results indicate that the increased pathogenicity in chickens of the recent Asian H5N1 HPAI viruses may be associated with extremely rapid and high replication of the virus in macrophages and vascular endothelial cells, which resulted in disruption of the thermoregulation system and innate immune responses.

Suzuki, Koutaro; Okada, Hironao; Itoh, Toshihiro; Tada, Tatsuya; Mase, Masaji; Nakamura, Kikuyasu; Kubo, Masanori; Tsukamoto, Kenji

2009-01-01

106

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

2013-06-01

107

Lettuce mosaic virus pathogenicity determinants in susceptible and tolerant lettuce cultivars map to different regions of the viral genome.  

PubMed

Full-length infectious cDNA clones were constructed for two isolates (LMV-0 and LMV-E) of Lettuce mosaic virus (LMV), a member of the genus Potyvirus. These two isolates differ in pathogenicity in susceptible and tolerant-resistant lettuce cultivars. In susceptible plants, LMV-0 induces mild mosaic symptoms, whereas LMV-E induces severe stunting, leaf deformation, and a necrotic mosaic. In plants carrying either of the two probably allelic recessive resistance genes mol1 or mol2, LMV-0 is restricted partially to the inoculated leaves. When a systemic invasion does occur, however, symptoms fail to develop. LMV-E overcomes the protection afforded by the resistance genes, resulting in systemic mosaic symptoms. Analysis of the behavior of recombinants constructed between the two virus isolates determined that the HC-Pro protein of LMV-E causes the severe stunting and necrotic mosaic induced by this isolate in susceptible cultivars. In contrast, the ability to overcome mol resistance and induce symptoms in the resistant-tolerant cultivars was mapped to the 3' half of the LMV-E genome. These results indicate that the ability to induce severe symptoms and to overcome the protection afforded by the recessive genes mol1 or mol2 are independent phenomena. PMID:11386376

Redondo, E; Krause-Sakate, R; Yang, S J; Lot, H; Le Gall, O; Candresse, T

2001-06-01

108

Susceptibility of Xenopus laevis tadpoles to infection by the ranavirus Frog-Virus 3 correlates with a reduced and delayed innate immune response in comparison with adult frogs  

PubMed Central

Xenopus laevis adults mount effective immune responses to ranavirus Frog Virus 3 (FV3) infections and clear the pathogen within 2–3 weeks. In contrast, most tadpoles cannot clear FV3 and succumb to infections within a month. While larval susceptibility has been attributed to ineffective adaptive immunity, the contribution of innate immune components has not been addressed. Accordingly, we performed a comprehensive gene expression analysis on FV3-infected tadpoles and adults. In comparison to adults, leukocytes and tissues of infected tadpoles exhibited modest (10–100 time lower than adult) and delayed (3 day later than adult) increase in expression of inflammation-associated (TNF-?, IL-1? and IFN-?) and antiviral (Mx1) genes. In contrast, these genes were readily and robustly upregulated in tadpoles upon bacterial stimulation. Furthermore, greater proportions of larval than adult PLs were infected by FV3. Our study suggests that tadpole susceptibility to FV3 infection is partially due to poor virus-elicited innate immune responses.

De Jesus Andino, Francisco; Chen, Guangchun; Li, Zhenghui; Grayfer, Leon; Robert, Jacques

2012-01-01

109

Orally administered Lactobacillus rhamnosus modulates the respiratory immune response triggered by the viral pathogen-associated molecular pattern poly(I:C)  

PubMed Central

Background Some studies have shown that probiotics, including Lactobacillus rhamnosus CRL1505, had the potential to beneficially modulate the outcome of certain bacterial and viral respiratory infections. However, these studies did not determine the mechanism(s) by which probiotics contribute to host defense against respiratory viruses. Results In this work we demonstrated that orally administered Lactobacillus rhamnosus CRL1505 (Lr1505) was able to increase the levels of IFN-?, IL-10 and IL-6 in the respiratory tract and the number of lung CD3+CD4+IFN-?+ T cells. To mimic the pro-inflammatory and physiopathological consecuences of RNA viral infections in the lung, we used an experimental model of lung inflammation based on the administration of the artificial viral pathogen-associated molecular pattern poly(I:C). Nasal administration of poly(I:C) to mice induced a marked impairment of lung function that was accompanied by the production of pro-inflammatory mediators and inflammatory cell recruitment into the airways. The preventive administration of Lr1505 reduced lung injuries and the production of TNF-?, IL-6, IL-8 and MCP-1 in the respiratory tract after the challenge with poly(I:C). Moreover, Lr1505 induced a significant increase in lung and serum IL-10. We also observed that Lr1505 was able to increase respiratory IFN-? levels and the number of lung CD3+CD4+IFN-?+ T cells after poly(I:C) challenge. Moreover, higher numbers of both CD103+ and CD11bhigh dendritic cells and increased expression of MHC-II, IL-12 and IFN-? in these cell populations were found in lungs of Lr1505-treated mice. Therefore, Lr1505 treatment would beneficially regulate the balance between pro-inflammatory mediators and IL-10, allowing an effective inflammatory response against infection and avoiding tissue damage. Conclusions Results showed that Lr1505 would induce a mobilization of cells from intestine and changes in cytokine profile that would be able to beneficially modulate the respiratory mucosal immunity. Although deeper studies are needed using challenges with respiratory viruses, the results in this study suggest that Lr1505, a potent inducer of antiviral cytokines, may be useful as a prophylactic agent to control respiratory virus infection.

2012-01-01

110

The mouse model is suitable for the study of viral factors governing transmission and pathogenesis of highly pathogenic avian influenza (HPAI) viruses in mammals  

PubMed Central

Highly pathogenic avian influenza (HPAI) viruses of the H5 and H7 subtype pose a major public health threat due to their capacity to cross the species barrier and infect mammals, for example dogs, cats and humans. In the present study we tested the capacity of selected H7 and H5 HPAI viruses to infect and to be transmitted from infected BALB/c mice to contact sentinels. Previous experiments have shown that viruses belonging to both H5 and H7 subtypes replicate in the respiratory tract and central nervous system of experimentally infected mice. In this study we show that selected H7N1 and H5N1 HPAI viruses can be transmitted from mouse-to-mouse by direct contact, and that in experimentally infected animals they exhibit a different pattern of replication and transmission. Our results can be considered as a starting point for transmission experiments involving other influenza A viruses with ? 2-3 receptor affinity in order to better understand the viral factors influencing transmissibility of these viruses in selected mammalian species.

Rigoni, Michela; Toffan, Anna; Viale, Elisabetta; Mancin, Marzia; Cilloni, Filippo; Bertoli, Elena; Salomoni, Angela; Marciano, Sabrina; Milani, Adelaide; Zecchin, Bianca; Capua, Ilaria; Cattoli, Giovanni

2010-01-01

111

BIOMARKERS OF VIRAL EXPOSURE  

EPA Science Inventory

Viral and protozoan pathogens associated with raw sludge can cause encephalitis, gastroenteritis, hepatitis, myocarditis, and a number of other diseases. Raw sludge that has been treated to reduce these pathogens can be used for land application according to the regulations spec...

112

Rapid differentiation of Australian, European and American ranaviruses based on variation in major capsid protein gene sequence.  

PubMed

Epizootic haematopoietic necrosis virus (EHNV), Bohle iridovirus (BIV) and Wamena virus (WV) cause serious diseases in fish, amphibians and snakes, respectively but are restricted to Australasia. European catfish virus (ECV) and sheatfish virus (ESV) have caused epizootics in fish on farms in continental Europe. Currently there are no simple or readily available methods to distinguish these viruses, which are in the Iridoviridae. They are culturally, morphologically and antigenically very similar to Frog Virus 3 (FV3), the type species in Ranavirus in this family and Gutapo virus (GV), another amphibian ranavirus from America. The diseases caused by EHNV, ESV and ECV are so serious that they are internationally notifiable. Tests to distinguish these viruses are desirable to ensure that disease occurrences do not unnecessarily restrict trade in aquaculture products. The gene encoding the major capsid protein from two EHNV isolates from different fish species (Perca fluviatilis and Oncorhynchus mykiss) and one BIV isolate were sequenced and the data and deduced amino acid sequences were compared with those from FV3 and other iridoviruses. The sequences for the two EHNV isolates were identical, confirming suggestions from existing partial MCP sequence that the same type of EHNV infects wild redfin perch and farmed rainbow trout. Differences in restriction endonuclease patterns of specific PCR products were predicted and confirmed between EHNV, BIV, and WV and provided a basis for rapid differentiation of these viruses from each other and from ESV/ECV and FV3/GV. These simple and rapid tests to distinguish important ranaviruses from the regions of Europe, Australia and America will help regulatory authorities assess the need for disease control responses in the event of occurrence of ranavirus infection in aquaculture species. PMID:12030764

Marsh, I B; Whittington, R J; O'Rourke, B; Hyatt, A D; Chisholm, O

2002-04-01

113

An improved enzyme linked immunosorbent assay for detection of anti-ranavirus antibodies in the serum of the giant toad (Bufo marinus).  

PubMed

An improved ranavirus antibody ELISA (R Ab ELISA) for the specific detection of anti-ranavirus antibodies in toad sera was developed. Sheep anti-epizootic haematopoietic necrosis virus (EHNV) was used as the antigen-capture antibody. EHNV was used as the antigen and sera from field and challenged toads were used to detect the virus. Rabbit anti-toad IgG and IgM were used to detect bound toad antibody. Pre-absorption of toad sera with a monoclonal antibody, raised against the 50 kDa EHNV protein, improved the specificity of the technique. A blocking ELISA, immunofluorescence and immuno-electron microscopy were used to confirm the validity of the ELISA. The assay has potential use in screening sera from Bufo marinus for the presence of antibodies against ranaviruses and to facilitate understanding of the humoral immunological response in toads during virus infection. PMID:9877438

Zupanovic, Z; Lopez, G; Hyatt, A; Shiell, B J; Robinson, A J

1998-01-01

114

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

115

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

116

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

117

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  

Microsoft Academic Search

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

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

2008-01-01

118

A Reverse Genetics System for the Great Lakes Strain of Viral Hemorrhagic Septicemia Virus: the NV Gene is Required for Pathogenicity  

Microsoft Academic Search

Viral hemorrhagic septicemia virus (VHSV), belonging to the genus Novirhabdovirus in the family of Rhabdoviridae, causes a highly contagious disease of fresh and saltwater fish worldwide. Recently, a novel genotype of VHSV, designated\\u000a IVb, has invaded the Great Lakes in North America, causing large-scale epidemics in wild fish. An efficient reverse genetics\\u000a system was developed to generate a recombinant VHSV

Arun Ammayappan; Gael Kurath; Tarin M. Thompson; Vikram N. Vakharia

119

Study of the kinetics of antibodies titres against viral pathogens and detection of rotavirus and parainfluenza 3 infections in captive crias of guanacos (Lama guanicoe).  

PubMed

A longitudinal study was conducted to investigate the presence of antibodies (Ab) to Rotavirus (RV), Parainfluenza-3 virus (PI-3), Bovine Herpesvirus-1 (BoHV-1), Bovine Viral Diarrhoea virus (BVDV-1) and Bluetongue virus (BTV) in eleven guanaco's crias (chulengos) relocated from Rio Negro to Buenos Aires Province (Argentina) and reared in captivity for a year in an experimental field. Serum samples were collected periodically to detect the evidence of viral infections. Faecal samples were collected to investigate RV shedding. We detected the evidence of Ab to RV from the beginning of the experience, suggesting the presence of maternal Ab against the virus. RV infection was detected in seven of the eleven chulengos, by seroconversion (4), virus shedding in stools (1) or both (2). In all cases, the RV strain was typed as [P1]G8, the same G/P type combination detected in captive chulengos with acute diarrhoea sampled in Rio Negro, in 2001. In contrast, we could not detect antibodies against PI-3, BoHV-1, BVDV or BT in any of initial samples. No Abs against BoHV-1, BVDV or BTV were detected in the chulengos throughout the study. However, all the chulengos became asymptomatically seropositive to PI-3 by the 7 month after arrival. This study suggest that wild-born guanacos raised in captivity can be relatively susceptible to common livestock viral infections, such as RV and PI-3, which are easily spread among chulengos. PMID:21062425

Marcoppido, G; Olivera, V; Bok, K; Parreño, V

2011-02-01

120

Viral Phylodynamics  

PubMed Central

Viral phylodynamics is defined as the study of how epidemiological, immunological, and evolutionary processes act and potentially interact to shape viral phylogenies. Since the coining of the term in 2004, research on viral phylodynamics has focused on transmission dynamics in an effort to shed light on how these dynamics impact viral genetic variation. Transmission dynamics can be considered at the level of cells within an infected host, individual hosts within a population, or entire populations of hosts. Many viruses, especially RNA viruses, rapidly accumulate genetic variation because of short generation times and high mutation rates. Patterns of viral genetic variation are therefore heavily influenced by how quickly transmission occurs and by which entities transmit to one another. Patterns of viral genetic variation will also be affected by selection acting on viral phenotypes. Although viruses can differ with respect to many phenotypes, phylodynamic studies have to date tended to focus on a limited number of viral phenotypes. These include virulence phenotypes, phenotypes associated with viral transmissibility, cell or tissue tropism phenotypes, and antigenic phenotypes that can facilitate escape from host immunity. Due to the impact that transmission dynamics and selection can have on viral genetic variation, viral phylogenies can therefore be used to investigate important epidemiological, immunological, and evolutionary processes, such as epidemic spread [2], spatio-temporal dynamics including metapopulation dynamics [3], zoonotic transmission, tissue tropism [4], and antigenic drift [5]. The quantitative investigation of these processes through the consideration of viral phylogenies is the central aim of viral phylodynamics.

Volz, Erik M.; Koelle, Katia; Bedford, Trevor

2013-01-01

121

Viral Gastroenteritis  

MedlinePLUS

... gastroenteritis in adults. Norovirus is usually responsible for epidemics of viral gastroenteritis. Norovirus outbreaks occur all year ... as the cause of the gastroenteritis. During an epidemic of viral gastroenteritis, health care providers or public ...

122

Characterisation of acute respiratory infections at a United Kingdom paediatric teaching hospital: observational study assessing the impact of influenza A (2009 pdmH1N1) on predominant viral pathogens  

PubMed Central

Background According to the World Health Organisation, influenza A (2009 pdmH1N1) has moved into the post-pandemic phase, but there were still high numbers of infections occurring in the United Kingdom in 2010-11. It is therefore important to examine the burden of acute respiratory infections at a large children’s hospital to determine pathogen prevalence, occurrence of co-infection, prevalence of co-morbidities and diagnostic yield of sampling methods. Methods This was a retrospective study of respiratory virus aetiology in acute admissions to a paediatric teaching hospital in the North West of England between 1st April 2010 and 31st March 2011. Respiratory samples were analysed either with a rapid RSV test if the patient had symptoms suggestive of bronchiolitis, followed by multiplex PCR testing for ten respiratory viruses, or with multiplex PCR testing alone if the patient had suspected other ARI. Patient demographics and data regarding severity of illness, presence of co-morbidities and respiratory virus sampling method were retrieved from case notes. Results 645 patients were admitted during the study period. 82/645 (12.7%) patients were positive for 2009 pdmH1N1, of whom 24 (29.2%) required PICU admission, with 7.3% mortality rate. Viral co-infection occurred in 48/645 (7.4%) patients and was not associated with more severe disease. Co-morbidities were present more frequently in older children, but there was no significant difference in prevalence of co-morbidity between 2009 pdmH1N1 patients and those with other ARI. NPA samples had the highest diagnostic yield with 192/210 (91.4%) samples yielding an organism. Conclusions Influenza A (2009 pdmH1N1) is an ongoing cause of occasionally severe disease affecting both healthy children and those with co-morbidities. Surveillance of viral pathogens provides valuable information on patterns of disease.

2014-01-01

123

Ecological Database of the World's Insect Pathogens  

NSDL National Science Digital Library

A search enabled relational database focusing on pathogens of insects including non-viral, viral, and nematodes, for purposes of insect control. This page does not include information about Bacillus thuringiensis (Bt). (shows 2002 as last update)

0002-11-30

124

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

125

A Novel Cytotoxic Sequence Contributes to Influenza A Viral Protein PB1-F2 Pathogenicity and Predisposition to Secondary Bacterial Infection  

PubMed Central

Enhancement of cell death is a distinguishing feature of H1N1 influenza virus A/Puerto Rico/8/34 protein PB1-F2. Comparing the sequences (amino acids [aa] 61 to 87 using PB1-F2 amino acid numbering) of the PB1-F2-derived C-terminal peptides from influenza A viruses inducing high or low levels of cell death, we identified a unique I68, L69, and V70 motif in A/Puerto Rico/8/34 PB1-F2 responsible for promotion of the peptide's cytotoxicity and permeabilization of the mitochondrial membrane. When administered to mice, a 27-mer PB1-F2-derived C-terminal peptide with this amino acid motif caused significantly greater weight loss and pulmonary inflammation than the peptide without it (due to I68T, L69Q, and V70G mutations). Similar to the wild-type peptide, A/Puerto Rico/8/34 elicited significantly higher levels of macrophages, neutrophils, and cytokines in the bronchoalveolar lavage fluid of mice than its mutant counterpart 7 days after infection. Additionally, infection of mice with A/Puerto Rico/8/34 significantly enhanced the levels of morphologically transformed epithelial and immune mononuclear cells recruited in the airways compared with the mutant virus. In the mouse bacterial superinfection model, both peptide and virus with the I68, L69, and V70 sequence accelerated development of pneumococcal pneumonia, as reflected by increased levels of viral and bacterial lung titers and by greater mortality. Here we provide evidence suggesting that the newly identified cytotoxic sequence I68, L69, and V70 of A/Puerto Rico/8/34 PB1-F2 contributes to the pathogenesis of both primary viral and secondary bacterial infections.

Samarasinghe, Amali; Vogel, Peter; Green, Amanda M.; Weinlich, Ricardo; McCullers, Jonathan A.

2014-01-01

126

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

127

Mapping the landscape of host-pathogen coevolution: HLA class I binding and its relationship with evolutionary conservation in human and viral proteins.  

PubMed

The high diversity of HLA binding preferences has been driven by the sequence diversity of short segments of relevant pathogenic proteins presented by HLA molecules to the immune system. To identify possible commonalities in HLA binding preferences, we quantify these using a novel measure termed "targeting efficiency," which captures the correlation between HLA-peptide binding affinities and the conservation of the targeted proteomic regions. Analysis of targeting efficiencies for 95 HLA class I alleles over thousands of human proteins and 52 human viruses indicates that HLA molecules preferentially target conserved regions in these proteomes, although the arboviral Flaviviridae are a notable exception where nonconserved regions are preferentially targeted by most alleles. HLA-A alleles and several HLA-B alleles that have maintained close sequence identity with chimpanzee homologues target conserved human proteins and DNA viruses such as Herpesviridae and Adenoviridae most efficiently, while all HLA-B alleles studied efficiently target RNA viruses. These patterns of host and pathogen specialization are both consistent with coevolutionary selection and functionally relevant in specific cases; for example, preferential HLA targeting of conserved proteomic regions is associated with improved outcomes in HIV infection and with protection against dengue hemorrhagic fever. Efficiency analysis provides a novel perspective on the coevolutionary relationship between HLA class I molecular diversity, self-derived peptides that shape T-cell immunity through ontogeny, and the broad range of viruses that subsequently engage with the adaptive immune response. PMID:21084470

Hertz, Tomer; Nolan, David; James, Ian; John, Mina; Gaudieri, Silvana; Phillips, Elizabeth; Huang, Jim C; Riadi, Gonzalo; Mallal, Simon; Jojic, Nebojsa

2011-02-01

128

A survey of selected parasitic and viral pathogens in four species of Mexican parrots, Amazona autumnalis, Amazona oratrix, Amazona viridigenalis, and Rhynchopsitta pachyrhyncha.  

PubMed

Isolated populations of four species of Mexican parrots were sampled for evidence of selected pathogens of concern in birds originating in Latin America. Data were collected between June and September 1997, and ectoparasite collection was repeated with Rhynchopsitta pachyrhyncha in September 2000. Serum samples from nine Amazona oratrix, 10 Amazona viridigenalis, 6 Amazona autumnalis, and 25 R. pachyrhyncha chicks were screened for neutralizing antibodies to psittacid herpesvirus and avian influenza and for antibodies to paramyxovirus serotypes 1 and 3. Chicks were also examined visually for fecal parasites and ectoparasites. All serologic and fecal parasite tests were negative. Ectoparasites included ticks, Ixodidae; mites, Ornithonyssus sylviarum; fleas, Psyttopsylla mexicana; lice, Paragoniocotes mexicanus, Heteromenopon sp., and Psittacobrosus sp.; and bugs, Ornithocoris sp. This study provides baseline information to guide future health studies. PMID:17323565

Stone, Elizabeth Gordon; Montiel-Parra, Griselda; Pérez, Tila Maria

2005-06-01

129

Semen-derived enhancer of viral infection (SEVI) binds bacteria, enhances bacterial phagocytosis by macrophages, and can protect against vaginal infection by a sexually transmitted bacterial pathogen.  

PubMed

The semen-derived enhancer of viral infection (SEVI) is a positively charged amyloid fibril that is derived from a self-assembling proteolytic cleavage fragment of prostatic acid phosphatase (PAP(248-286)). SEVI efficiently facilitates HIV-1 infection in vitro, but its normal physiologic function remains unknown. In light of the fact that other amyloidogenic peptides have been shown to possess direct antibacterial activity, we investigated whether SEVI could inhibit bacterial growth. Neither SEVI fibrils nor the unassembled PAP(248-286) peptide had significant direct antibacterial activity in vitro. However, SEVI fibrils bound to both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli and Neisseria gonorrhoeae) bacteria, in a charge-dependent fashion. Furthermore, SEVI fibrils but not the monomeric PAP(248-286) peptide promoted bacterial aggregation and enhanced the phagocytosis of bacteria by primary human macrophages. SEVI also enhanced binding of bacteria to macrophages and the subsequent release of bacterially induced proinflammatory cytokines (tumor necrosis factor alpha [TNF-?], interleukin-6 [IL-6], and IL-1?). Finally, SEVI fibrils inhibited murine vaginal colonization with Neisseria gonorrhoeae. These findings demonstrate that SEVI has indirect antimicrobial activity and that this activity is dependent on both the cationic charge and the fibrillar nature of SEVI. PMID:23507280

Easterhoff, David; Ontiveros, Fernando; Brooks, Lauren R; Kim, Yoel; Ross, Brittany; Silva, Jharon N; Olsen, Joanna S; Feng, Changyong; Hardy, Dwight J; Dunman, Paul M; Dewhurst, Stephen

2013-06-01

130

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

2013-01-01

131

The impact of viral tropism and housing conditions on the transmission of three H5/H7 low pathogenic avian influenza viruses in chickens.  

PubMed

In this study, shedding and transmission of three H5/H7 low pathogenic avian influenza viruses (LPAIVs) in poultry was characterized and the impact of floor system on transmission was assessed. Transmission experiments were simultaneously conducted with two groups of animals housed on either a grid or a floor covered with litter. Transmission was observed for H5N2 A/Ch/Belgium/150VB/99 LPAIV. This virus was shed almost exclusively via the oropharynx and no impact of floor system was seen. Transmission was also seen for H7N1 A/Ch/Italy/1067/v99 LPAIV, which was shed via both the oropharynx and cloaca. A slight increase in transmission was seen for animals housed on litter. H5N3 A/Anas Platyrhynchos/Belgium/09-884/2008 LPAIV did not spread to susceptible animals, regardless of the floor system. This study shows that environmental factors such as floor systems used in poultry barns may act upon the transmission of LPAIVs. However, the level of influence depends on the virus under consideration and, more specifically, its principal replication sites. PMID:23398968

Claes, G; Welby, S; Van Den Berg, T; Van Der Stede, Y; Dewulf, J; Lambrecht, B; Marché, S

2013-11-01

132

Detection of viral pathogens by reverse transcriptase PCR and of microbial indicators by standard methods in the canals of the Florida Keys.  

PubMed

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. PMID:10473424

Griffin, D W; Gibson, C J; Lipp, E K; Riley, K; Paul, J H; Rose, J B

1999-09-01

133

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

134

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

2013-03-01

135

Viral Meningitis  

MedlinePLUS

... viral infections that can lead to meningitis include Mumps Herpes virus, including Epstein-Barr virus, herpes simplex ... of an infected person. Other viruses, such as mumps and varicella-zoster virus, may also be spread ...

136

Viral induced yeast apoptosis.  

PubMed

In an analogous system to mammals, induction of an apoptotic cell death programme (PCD) in yeast is not only restricted to various exogenous factors and stimuli, but can also be triggered by viral killer toxins and viral pathogens. In yeast, toxin secreting killer strains are frequently infected with double-stranded (ds)RNA viruses that are responsible for killer phenotype expression and toxin secretion in the infected host. In most cases, the viral toxins are either pore-forming proteins (such as K1, K2, and zygocin) that kill non-infected and sensitive yeast cells by disrupting cytoplasmic membrane function, or protein toxins (such as K28) that act in the nucleus by blocking DNA synthesis and subsequently causing a G1/S cell cycle arrest. Interestingly, while all these virus toxins cause necrotic cell death at high concentration, they trigger caspase- and ROS-mediated apoptosis at low-to-moderate concentration, indicating that even low toxin doses are deadly by triggering PCD in enemy cells. Remarkably, viral toxins are not solely responsible for cell death induction in vivo, as killer viruses themselves were shown to trigger apoptosis in non-infected yeast. Thus, as killer virus-infected and toxin secreting yeasts are effectively protected and immune to their own toxin, killer yeasts bear the intrinsic potential to dominate over time in their natural habitat. PMID:18291112

Schmitt, Manfred J; Reiter, Jochen

2008-07-01

137

Viral exanthems.  

PubMed

Viral exanthems are mostly associated with self-limited diseases. However, in some cases diagnosis of an exanthem may be crucial to patients and their contacts. Certain exanthems have fairly characteristic morphology, but in many cases an accurate diagnosis cannot be made on the basis of morphology alone. Historical factors may be helpful when evaluating these patients, specifically their disease contacts, immunization record, previous exanthematous illnesses, and associated prodromal symptoms. Some illnesses are seasonal and this knowledge may be useful. This manuscript reviews a number of common childhood exanthems. We included the most common viral exanthems encountered by primary-care physicians and dermatologists. PMID:12952751

Scott, Lycia A; Stone, Mary Seabury

2003-08-01

138

Viral Gastroenteritis.  

National Technical Information Service (NTIS)

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...

N. R. Blacklow G. Cukor

1984-01-01

139

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...

140

Snapshots: Chromatin Control of Viral Infection  

PubMed Central

Like their cellular host counterparts, many invading viral pathogens must contend with, modulate, and utilize the host cell’s chromatin machinery to promote efficient lytic infection or control persistent-latent states. While not intended to be comprehensive, this review represents a compilation of conceptual snapshots of the dynamic interplay of viruses with the chromatin environment. Contributions focus on chromatin dynamics during infection, viral circumvention of cellular chromatin repression, chromatin organization of large DNA viruses, tethering and persistence, viral interactions with cellular chromatin modulation machinery, and control of viral latency-reactivation cycles.

Knipe, David M.; Lieberman, Paul M.; Jung, Jae U.; McBride, Alison A.; Morris, Kevin V.; Ott, Melanie; Margolis, David; Nieto, Amelia; Nevels, Michael; Parks, Robin J.; Kristie, Thomas M.

2012-01-01

141

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...

142

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

143

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

144

Viral vectors for vaccine applications.  

PubMed

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. PMID:23858400

Choi, Youngjoo; Chang, Jun

2013-07-01

145

Viral infections.  

PubMed

Although rubella is the only virus which can be regarded in the strict sense of the term a teratogen, there is no convincing evidence that other viruses can cause fetal damage of varying severity. The risk to the fetus appears to depend on the nature of the infectious agent, the maternal immune status and the gestational age when infection takes place. The possibility that subclinical maternal infections may cause damage must not be overlooked. As some of the viruses referred to can cause damage after the period of organogenesis, the use of the term 'teratogenic efect' in relation to viral infections is considered to be inappropriate. PMID:184117

Dudgeon, J A

1976-01-01

146

Viral and host proteins involved in picornavirus life cycle.  

PubMed

Picornaviruses cause several diseases, not only in humans but also in various animal hosts. For instance, human enteroviruses can cause hand-foot-and-mouth disease, herpangina, myocarditis, acute flaccid paralysis, acute hemorrhagic conjunctivitis, severe neurological complications, including brainstem encephalitis, meningitis and poliomyelitis, and even death. The interaction between the virus and the host is important for viral replication, virulence and pathogenicity. This article reviews studies of the functions of viral and host factors that are involved in the life cycle of picornavirus. The interactions of viral capsid proteins with host cell receptors is discussed first, and the mechanisms by which the viral and host cell factors are involved in viral replication, viral translation and the switch from translation to RNA replication are then addressed. Understanding how cellular proteins interact with viral RNA or viral proteins, as well as the roles of each in viral infection, will provide insights for the design of novel antiviral agents based on these interactions. PMID:19925687

Lin, Jing-Yi; Chen, Tzu-Chun; Weng, Kuo-Feng; Chang, Shih-Cheng; Chen, Li-Lien; Shih, Shin-Ru

2009-01-01

147

Anti-viral properties and mode of action of standardized Echinacea purpurea extract against highly pathogenic avian Influenza virus (H5N1, H7N7) and swine-origin H1N1 (SOIV)  

Microsoft Academic Search

BACKGROUND: Influenza virus (IV) infections are a major threat to human welfare and animal health worldwide. Anti-viral therapy includes vaccines and a few anti-viral drugs. However vaccines are not always available in time, as demonstrated by the emergence of the new 2009 H1N1-type pandemic strain of swine origin (S-OIV) in April 2009, and the acquisition of resistance to neuraminidase inhibitors

Stephan Pleschka; Michael Stein; Roland Schoop; James B Hudson

2009-01-01

148

Pathogen-pathogen interaction  

PubMed Central

There is growing awareness of the health implications of the fact that infectious agents often do not act independently; rather their disease potential is mediated in diverse and significant ways by their relationships with other pathogens. Pathogen-pathogen interaction (PPI), for example, impacts various virulence factors in human infection. Although still in its infancy, the study of PPI, a form of epidemiological synergism, is emerging as an important arena of new research and new understanding in health and clinical care. The aims of this paper are to: (1) draw attention to the role of PPI in human disease patterns; (2) present the syndemics model as a biosocial approach for examining the nature, pathways, contexts, and health implications of PPI and (3) suggest the utility of this approach to PPI. Toward these ends, this paper (a) reviews three case examples of alternative PPIs, (b) describes the development and key concepts and components of the syndemics model with specific reference to interacting infectious agents, (c) contextualizes this discussion with a brief review of broader syndemics disease processes (not necessarily involving infections disease) and (d) comments on the research, treatment and prevention implications of syndemic interaction among pathogens.

2010-01-01

149

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

2005-01-01

150

Viral Quasispecies Evolution  

PubMed Central

Summary: 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.

Sheldon, Julie; Perales, Celia

2012-01-01

151

Viral Hijackers  

NSDL National Science Digital Library

Students learn how viruses invade host cells and hijack the hosts' cell-reproduction mechanisms in order to make new viruses, which can in turn attack additional host cells. Students also learn how the immune system responds to a viral invasion, eventually defeating the virusesâif all goes well. Finally, they consider the special case of HIV, in which the virus' host cell is a key component of the immune system itself, severely crippling it and ultimately leading to AIDS. The associated activity sets the stage for this lesson with a dramatic simulation that allows students to see for themselves how quickly a virus can spread through a population, and then challenges students to determine who the initial bearers of the virus were.

Engineering K-Phd Program

152

Viral infections of rabbits.  

PubMed

Viral diseases of rabbits have been used historically to study oncogenesis (e.g. rabbit fibroma virus, cottontail rabbit papillomavirus) and biologically to control feral rabbit populations (e.g. myxoma virus). However, clinicians seeing pet rabbits in North America infrequently encounter viral diseases although myxomatosis may be seen occasionally. The situation is different in Europe and Australia, where myxomatosis and rabbit hemorrhagic disease are endemic. Advances in epidemiology and virology have led to detection of other lapine viruses that are now recognized as agents of emerging infectious diseases. Rabbit caliciviruses, related to rabbit hemorrhagic disease, are generally avirulent, but lethal variants are being identified in Europe and North America. Enteric viruses including lapine rotavirus, rabbit enteric coronavirus and rabbit astrovirus are being acknowledged as contributors to the multifactorial enteritis complex of juvenile rabbits. Three avirulent leporid herpesviruses are found in domestic rabbits. A fourth highly pathogenic virus designated leporid herpesvirus 4 has been described in Canada and Alaska. This review considers viruses affecting rabbits by their clinical significance. Viruses of major and minor clinical significance are described, and viruses of laboratory significance are mentioned. PMID:23642871

Kerr, Peter J; Donnelly, Thomas M

2013-05-01

153

Diagnostics and discovery in viral hemorrhagic fevers.  

PubMed

The rate of discovery of new microbes and of new associations of microbes with health and disease is accelerating. Many factors contribute to this phenomenon including those that favor the true emergence of new pathogens as well as new technologies and paradigms that enable their detection and characterization. This chapter reviews recent progress in the field of pathogen surveillance and discovery with a focus on viral hemorrhagic fevers. PMID:19751404

Lipkin, W Ian; Palacios, Gustavo; Briese, Thomas

2009-09-01

154

Diagnostics and Discovery in Viral Hemorrhagic Fevers  

PubMed Central

The rate of discovery of new microbes and of new associations of microbes with health and disease is accelerating. Many factors contribute to this phenomenon including those that favor the true emergence of new pathogens as well as new technologies and paradigms that enable their detection and characterization. This chapter reviews recent progress in the field of pathogen surveillance and discovery with a focus on viral hemorrhagic fevers.

Lipkin, W. Ian; Palacios, Gustavo; Briese, Thomas

2014-01-01

155

[32] Identification of viral infection by confocal microscopy  

Microsoft Academic Search

Confocal microscopy is a valuable adjunct to electron microscopy in the fields of diagnostic and investigative virology. Confocal imaging can be used to examine large amounts of tissue stained by a variety of methods for evidence of viral infection. Areas thus identified can then be processed for ultrastructural study, allowing a highly focused search for viral pathogens. With the possible

David N. Howell; Sara E. Miller

1999-01-01

156

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

157

NLRs, inflammasomes, and viral infection  

PubMed Central

NLR proteins are innate immune sensors that respond to microbial infection. Upon pathogen infection, some NLR proteins form large complexes, called inflammasomes, which activate caspase-1 and induce the production of active IL-1? and IL-18. Activation of inflammasomes can also lead to an inflammatory cell death program, named pyroptosis. In this review, we will discuss the role of various NLR proteins in sensing different viral infections, as well as the strategies used by several RNA and DNA viruses to counteract the antiviral effects of NLR-dependent inflammasomes.

Jacobs, Sarah R.; Damania, Blossom

2012-01-01

158

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

159

Mutations in the Highly Conserved SLQYLA Motif of Vif in a Simian-Human Immunodeficiency Virus Result in a Less Pathogenic Virus and is Associated with G-to-A Mutations in the Viral Genome  

PubMed Central

The simian-human immunodeficiency virus (SHIV)/macaque model for human immunodeficiency virus type 1 has become a useful tool to assess the role of accessory genes in lentiviral pathogenesis. In this study, we introduced two amino acid changes in the highly conserved SLQYLA domain (to AAQYLA) of the SIV Vif protein. The resulting virus, SHIVVifAAQYLA, was used to infect three macaques, which were followed for over six months. Plasma viral loads and circulating CD4+ T cell levels were assessed during the course of infection. The three macaques inoculated with SHIVVifAAQYLA did not develop significant CD4+ T cell loss over the course of their infection, had plasma viral RNA loads that were over 100-fold lower than macaques inoculated with parental SHIVKU-1bMC33, and developed no histological lesions in lymphoid tissues. DNA and RT-PCR analysis revealed that only a select number of tissues were infected with this virus. Sequence analysis indicates that the site-directed changes were stable during the first three weeks after inoculation but thereafter the S147A amino acid substitution changed to a threonine in two of three macaques. The L148A substitution remained stable in the vif amplified from the PBMC of all three macaques. Sequence analysis of vif, vpu, env and nef genes revealed G-to-A mutations in the genes amplified from macaques inoculated with SHIVVifAAQYLA, which were higher than in a macaque inoculated with parental SHIVKU-1bMC33. We found that the majority (>85%) of the G-to-A mutations were in the context of 5?-TC (minus strand) and not 5?-CC, suggestive that one or more of the rhesus APOBEC3 proteins may be responsible for the observed mutational patterns with rhesus APOBEC3G for a minority of the mutations since its GG-to-AG mutational pattern was infrequently detected. Finally, macaques inoculated with SHIVVifAAQYLA developed immunoprecipitating antibody responses against the virus. The results from this study provide the first in vivo evidence of the importance of the SLQYLA domain in viral pathogenesis and show that targeted mutations in vif can lead to a persistent infection with G-to-A changes accumulating in the viral genome.

Schmitt, Kimberly; Hill, M. Sarah; Ruiz, Autumn; Culley, Nathan; Pinson, David M.; Wong, Scott W.

2014-01-01

160

Broad-Spectrum Drugs Against Viral Agents  

PubMed Central

Development of antivirals has focused primarily on vaccines and on treatments for specific viral agents. Although effective, these approaches may be limited in situations where the etiologic agent is unknown or when the target virus has undergone mutation, recombination or reassortment. Augmentation of the innate immune response may be an effective alternative for disease amelioration. Nonspecific, broad-spectrum immune responses can be induced by double-stranded (ds)RNAs such as poly (ICLC), or oligonucleotides (ODNs) containing unmethylated deocycytidyl-deoxyguanosinyl (CpG) motifs. These may offer protection against various bacterial and viral pathogens regardless of their genetic makeup, zoonotic origin or drug resistance.

Christopher, Mary E.; Wong, Jonathan P.

2008-01-01

161

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

2013-10-01

162

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 Central

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.

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

2013-01-01

163

Prevalence of selected pathogens in western pond turtles and sympatric introduced red-eared sliders in California, USA.  

PubMed

Pathogen introduction by invasive species has been speculated to be a cause of declining western pond turtle Emys marmorata populations in California, USA. This study determined the prevalence of Ranavirus spp., Herpesvirus spp., Mycoplasma spp. (via polymerase chain reaction of blood and nasal flush contents), and Salmonella spp. infection (via fecal culture) in native E. marmorata and invasive red-eared sliders Trachemys scripta elegans and compared infection prevalence in E. marmorata populations sympatric with T. scripta elegans to E. marmorata populations that were not sympatric by sampling 145 E. marmorata and 33 T. scripta elegans at 10 study sites throughout California. Mycoplasma spp. were detected in both species: prevalence in E. marmorata was 7.8% in the northern, 9.8% in the central, and 23.3% in the southern California regions. In T. scripta elegans, Mycoplasma spp. were not detected in the northern California region but were detected at 4.5 and 14.3% in the central and southern regions, respectively. All turtles tested negative for Herpesvirus spp. and Ranavirus spp. Enteric bacteria but not Salmonella spp. were isolated from feces. E. marmorata populations that were sympatric with T. scripta elegans did not have increased risk of Mycoplasma spp. infection. For E. marmorata, there was a significant association between Mycoplasma spp. infection and lower body weight and being located in the southern California region. This study is the first of its kind to document pathogen prevalence in native E. marmorata habitats and those sympatric with T. scripta elegans in California. PMID:24270022

Silbernagel, C; Clifford, D L; Bettaso, J; Worth, S; Foley, J

2013-11-25

164

In silico Microarray Probe Design for Diagnosis of Multiple Pathogens.  

National Technical Information Service (NTIS)

With multiple strains of various pathogens being sequenced, it is necessary to develop high-throughput methods that can simultaneously process multiple bacterial or viral genomes to find common fingerprints as well as fingerprints that are unique to each ...

E. Bode K. Kumar N. Zavaljevski R. V. Satya S. Padilla

2008-01-01

165

Diagnosis and treatment of viral diseases in recipients of allogeneic hematopoietic stem cell transplantation  

PubMed Central

Viral infections are important causes of morbidity and mortality after allogeneic stem cell hematopoietic transplantation (allo-HSCT). Although most viral infections present with asymptomatic or subclinical manifestations, viruses may result in fatal complications in severe immunocompromised recipients. Reactivation of latent viruses, such as herpesviruses, is frequent during the immunosuppression that occurs with allo-HSCT. Viruses acquired from community, such as the respiratory and gastrointestinal viruses, are also important pathogens of post-transplant viral diseases. Currently, molecular diagnostic methods have replaced or supplemented traditional methods, such as viral culture and antigen detection, in diagnosis of viral infections. The utilization of polymerase chain reaction facilitates the early diagnosis. In view of lacking efficacious agents for treatment of viral diseases, prevention of viral infections is extremely valuable. Application of prophylactic strategies including preemptive therapy reduces viral infections and diseases. Adoptive cellular therapy for restoring virus-specific immunity is a promising method in the treatment of viral diseases.

2013-01-01

166

Monitoring Viral Load  

Microsoft Academic Search

The ability to measure HIV-1 viral load has revolutionized our ability to track HIV infection and viral replication. The advent\\u000a of viral load assays has been both a technologic and pragmatic feat, supplying a sturdy clinical measure to guide clinical\\u000a AIDS management. Formerly, clinicians and scientists relied on difficult and cumbersome plasma and peripheral blood mononuclear\\u000a cell cultures for virus

Phyllis J. Kanki; Indu Mani

167

Mobile Viral Marketing  

Microsoft Academic Search

Gerade in Zeiten zunehmender Reizüberflutung und steigender Reaktanz gegenüber traditionellen Werbeformen gewinnen innovative\\u000a Marketinginstrumente, wie Mobile Viral Marketing, verstärkt an Bedeutung. Ziel des vorliegenden Beitrages ist es, den State\\u000a of the Art des Mobile Viral Marketing zu analysieren. Der Beitrag stellt zunächst Mobile Viral Marketing in Form eines strukturellen\\u000a Beschreibungsmodells unter Verwendung der morphologischen Methode vor. Anschließend werden der Stand

K. Pousttchi; K. Turowski; D. G. Wiedemann

168

Cannabinoids and Viral Infections  

PubMed Central

Exogenous cannabinoids or receptor antagonists may influence many cellular and systemic host responses. The anti-inflammatory activity of cannabinoids may compromise host inflammatory responses to acute viral infections, but may be beneficial in persistent infections. In neurons, where innate antiviral/pro-resolution responses include the activation of NOS-1, inhibition of Ca2+ activity by cannabinoids, increased viral replication and disease. This review examines the effect(s) of cannabinoids and their antagonists in viral infections.

Reiss, Carol Shoshkes

2010-01-01

169

Live viral vaccines for respiratory and enteric tract diseases.  

PubMed

In its programme for accelerated development of vaccines for viral respiratory and enteric tract diseases the WHO has assigned a very high priority to respiratory syncytial virus (RSV), parainfluenza viruses and rotaviruses. There is also some interest in alternative approaches to immunization against influenza viruses because of the failure of inactivated vaccines to provide complete and reasonably durable immunity. Current attempts to develop satisfactorily attenuated viruses for use in prevention of disease caused by the above viral pathogens are described. PMID:2838984

Chanock, R M; Murphy, B R; Collins, P L; Coelingh, K V; Olmsted, R A; Snyder, M H; Spriggs, M K; Prince, G A; Moss, B; Flores, J

1988-04-01

170

Pathogen intelligence.  

PubMed

Different species inhabit different sensory worlds and thus have evolved diverse means of processing information, learning and memory. In the escalated arms race with host defense, each pathogenic bacterium not only has evolved its individual cellular sensing and behavior, but also collective sensing, interbacterial communication, distributed information processing, joint decision making, dissociative behavior, and the phenotypic and genotypic heterogeneity necessary for epidemiologic success. Moreover, pathogenic populations take advantage of dormancy strategies and rapid evolutionary speed, which allow them to save co-generated intelligent traits in a collective genomic memory. This review discusses how these mechanisms add further levels of complexity to bacterial pathogenicity and transmission, and how mining for these mechanisms could help to develop new anti-infective strategies. PMID:24551600

Steinert, Michael

2014-01-01

171

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

2012-02-01

172

Therapy of Viral Hepatitis  

Microsoft Academic Search

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

Jay H. Hoofnagle

1998-01-01

173

Viral Disease Networks?  

NASA Astrophysics Data System (ADS)

Viral infections induce multiple perturbations that spread along the links of the biological networks of the host cells. Understanding the impact of these cascading perturbations requires an exhaustive knowledge of the cellular machinery as well as a systems biology approach that reveals how individual components of the cellular system function together. Here we describe an integrative method that provides a new approach to studying virus-human interactions and its correlations with diseases. Our method involves the combined utilization of protein - protein interactions, protein -- DNA interactions, metabolomics and gene - disease associations to build a ``viraldiseasome''. By solely using high-throughput data, we map well-known viral associated diseases and predict new candidate viral diseases. We use microarray data of virus-infected tissues and patient medical history data to further test the implications of the viral diseasome. We apply this method to Epstein-Barr virus and Human Papillomavirus and shed light into molecular development of viral diseases and disease pathways.

Gulbahce, Natali; Yan, Han; Vidal, Marc; Barabasi, Albert-Laszlo

2010-03-01

174

The evolution of bovine viral diarrhea: a review  

PubMed Central

The economic importance of bovine viral diarrhea is increasing with the emergence of seemingly more virulent viruses, as evidenced by outbreaks of hemorrhagic syndrome and severe acute bovine viral diarrhea beginning in the 1980s and 1990s. It appears that evolutionary changes in bovine viral diarrhea virus were responsible for these outbreaks. The genetic properties of the classical bovine viral diarrhea virus that contribute to the basis of current diagnostic tests, vaccines, and our understanding of pathogenic mechanisms are now being reevaluated because of these “new” virus strains. This shift in virulence has confounded both nomenclature and the significance of current bovine viral diarrhea virus categorization. The purpose of this review is to summarize our current understanding of bovine viral diarrhea virus with a chronological review of prevailing scientific tenets and practices as described in clinical and scientific North American veterinary journals and textbooks. The first part of this review describes how we have arrived at our current understanding of the viruses, the diseases, and their nomenclature. The second part of the review deals with current concepts in virology and how these concepts may both explain and predict bovine viral diarrhea virus pathogenesis. By reviewing how knowledge of bovine viral diarrhea has evolved and the theories of how the virus itself is able to evolve, the interpretation of diagnostic tests are more effectively utilized in the control and treatment of bovine viral diarrhea virus associated disease.

Goens, Denise

2002-01-01

175

Genome-Wide Survey of Host Responses: Use of Computational Analysis to Classify Exposures and Extract Signatures of Unconventional Versus Common Viral Exposures.  

National Technical Information Service (NTIS)

Exposures to many unconventional pathogenic agents result in flu- like illness that are initially indistinguishable from common respiratory illnesses and early diagnosis to distinguish among the severe vs common viral infections depends on pathogen prolif...

M. Jett R. Hammamieh

2006-01-01

176

Countermeasures against viral diseases of farmed fish.  

PubMed

Farmed fish provide an increasing fraction of the human food supply, and are of major economic importance in many countries. As in the case of terrestrial agriculture, bringing together large numbers of animals of a single species (i.e., monoculture) increases the risk of infectious disease outbreaks, including viral infections. Aquaculture, in which farmed fish are kept at high population densities in close proximity with wild fish reservoirs, is ideal for the emergence of wild-type pathogens that exist benignly in local wild fish and/or the spreading of aquatic pathogens to wild fish that enter into or come into close proximity with net cages and with fish escaping from them. This paper provides a general review for the nonspecialist of viral diseases of farmed fish and how they could be prevented or treated. It has five principal objectives: (1) to provide an update on the most important and emerging viral diseases of salmonid aquaculture; (2) to review general aspects of innate antiviral defense against virus infections in fish, including recent advances in antiviral signaling; (3) to discuss current principles and practices of vaccinating fish; (4) to review antiviral drugs that have activity against viruses of farmed fish, and current barriers to employing them in aquaculture; and (5) to discuss the growing use of "functional feeds" in salmonid aquaculture to mitigate viral diseases. In conclusion, despite the challenging aquatic environment, it is expected that well thought-out combinations of vaccination and immunostimulants and/or antiviral drugs could provide solid protection against viral diseases of farmed fish. PMID:22721634

Kibenge, Frederick S B; Godoy, Marcos G; Fast, Mark; Workenhe, Samuel; Kibenge, Molly J T

2012-09-01

177

Viral diseases of marine invertebrates  

NASA Astrophysics Data System (ADS)

Approximately 40 viruses are known from marine sponges; turbellarian and monogenetic flatworms; cephalopod, bivalve, and gastropod mollusks; nereid polychaetes; and isopod and decapod crustaceans. Most of the viruses can be tentatively assigned to the Herpesviridae, Baculoviridae, Iridoviridae, Adenoviridae, Papovaviridae, Reoviridae, “Birnaviridae”, Bunyaviridae, Rhabdoviridae, and Picornaviridae. Viruslike particles found in oysters might be representatives of the Togaviridae and Retroviridae. Enveloped single-stranded RNA viruses from crustaceans have developmental and morphological characteristics intermediate between families, and some show evidence of relationships to the Paramyxoviridae as well as the Bunyaviridae or Rhabdoviridae. Certain small viruses of shrimp cannot be assigned, even tentatively, to a particular family. Some viruses cause disease in wild and captive hosts, others are associated with disease states but may not be primary instigators, and many occur in apparently normal animals. The frequency of viral disease in natural populations of marine invertebrates is unknown. Several viruses that cause disease in captive animals, with or without experimental intervention, have also been found in diseased wild hosts, including herpeslike viruses of crabs and oysters, iridovirus of octopus, and reolike and bunyalike viruses of crabs. Iridolike viruses have been implicated in massive mortalities of cultured oysters. Baculoviruses, and IHHN virus, which is of uncertain affinities, cause economically damaging diseases in cultured penaeid shrimp. Double or multiple viral infection is common in crabs. For example, a reolike virus and associated rhabdolike virus act synergistically to cause paralytic and fatal disease in Callinectes sapidus. Information on host range, most susceptible stage, and viral latency is available only for viruses of shrimp. One baculovirus attacks five species of New World penaeid shrimp. IHHN virus infects three species of Penaeus and causes catastrophic mortalities in P. stylirostris, but usually exhibits only inapparent infection in P. vannamei. Some shrimp viruses apparently are latent in larvae, causing disease only when shrimp have reached the postlarval or juvenile stages. Others are equally or more pathogenic in larvae. Studies of shrimp viruses and iridovirus-associated disease in cultured oysters point up the need for rapid and accurate diagnostic methods. Until appropriate cell cultures from marine invertebrates are devised, the viral identifications necessary for understanding of epizootiology, rapid containment of epizootics in cultured animals, and decisions regarding introductions of exotic species will be difficult or impossible.

Johnson, P. T.

1984-03-01

178

Involvement of the Zinc-Binding Capacity of Sendai Virus V Protein in Viral Pathogenesis  

Microsoft Academic Search

The V protein of Sendai virus (SeV) is nonessential to virus replication in cell culture but indispensable to viral pathogenicity in mice. The highly conserved cysteine-rich zinc finger-like domain in its carboxyl terminus is believed to be responsible for this viral pathogenicity. In the present study, we showed that the cysteine-rich domain of the SeV V protein could actually bind

CHENG HUANG; KATSUHIRO KIYOTANI; YUTAKA FUJII; NORIKO FUKUHARA; ATSUSHI KATO; YOSHIYUKI NAGAI; TETSUYA YOSHIDA; TAKEMASA SAKAGUCHI

2000-01-01

179

Neuropathology of viral infections.  

PubMed

Advancements in diagnostic methods, particularly polymerase chain reaction (PCR)-based testing of cerebrospinal fluid for viral nucleic acids, have diminished the role of neuropathologic examination in the diagnosis of viral infections of the central nervous system (CNS). Nevertheless, neuropathologic examination of CNS tissue remains important in the diagnosis of atypical viral encephalitides and in the exclusion of non-infectious etiologies. In addition to routine hematoxylin and eosin stains on tissue sections, the neuropathologist may utilize immunohistochemistry, in situ hybridization, electron microscopy, and PCR-based testing of the tissue specimen. In this review, we cover the general pathologic features of viral infections of the CNS as well as the specific features of CNS infections caused by poliovirus, herpes simplex virus, varicella-zoster virus, Epstein-Barr virus, cytomegalovirus, rabies virus, West Nile virus, Eastern equine encephalitis virus, measles virus, JC virus, human immunodeficiency virus, and human T lymphotropic virus type 1. PMID:25015486

Hatanpaa, Kimmo J; Kim, Jung H

2014-01-01

180

Viral Hepatitis Therapies  

MedlinePLUS

... brand name for additional information. Approved Treatments for Hepatitis B Brand Name Generic Names Manufacturer Name Indication Baraclude entecavir Bristol-Myers Squibb chronic hepatitis B virus infection with evidence of active viral replication ...

181

The Fecal Viral Flora of Wild Rodents  

PubMed Central

The frequent interactions of rodents with humans make them a common source of zoonotic infections. To obtain an initial unbiased measure of the viral diversity in the enteric tract of wild rodents we sequenced partially purified, randomly amplified viral RNA and DNA in the feces of 105 wild rodents (mouse, vole, and rat) collected in California and Virginia. We identified in decreasing frequency sequences related to the mammalian viruses families Circoviridae, Picobirnaviridae, Picornaviridae, Astroviridae, Parvoviridae, Papillomaviridae, Adenoviridae, and Coronaviridae. Seventeen small circular DNA genomes containing one or two replicase genes distantly related to the Circoviridae representing several potentially new viral families were characterized. In the Picornaviridae family two new candidate genera as well as a close genetic relative of the human pathogen Aichi virus were characterized. Fragments of the first mouse sapelovirus and picobirnaviruses were identified and the first murine astrovirus genome was characterized. A mouse papillomavirus genome and fragments of a novel adenovirus and adenovirus-associated virus were also sequenced. The next largest fraction of the rodent fecal virome was related to insect viruses of the Densoviridae, Iridoviridae, Polydnaviridae, Dicistroviriade, Bromoviridae, and Virgaviridae families followed by plant virus-related sequences in the Nanoviridae, Geminiviridae, Phycodnaviridae, Secoviridae, Partitiviridae, Tymoviridae, Alphaflexiviridae, and Tombusviridae families reflecting the largely insect and plant rodent diet. Phylogenetic analyses of full and partial viral genomes therefore revealed many previously unreported viral species, genera, and families. The close genetic similarities noted between some rodent and human viruses might reflect past zoonoses. This study increases our understanding of the viral diversity in wild rodents and highlights the large number of still uncharacterized viruses in mammals.

Phan, Tung G.; Kapusinszky, Beatrix; Wang, Chunlin; Rose, Robert K.; Lipton, Howard L.; Delwart, Eric L.

2011-01-01

182

Viral membrane fusion  

Microsoft Academic Search

Infection by viruses having lipid-bilayer envelopes proceeds through fusion of the viral membrane with a membrane of the target cell. Viral 'fusion proteins' facilitate this process. They vary greatly in structure, but all seem to have a common mechanism of action, in which a ligand-triggered, large-scale conformational change in the fusion protein is coupled to apposition and merger of the

Stephen C Harrison

2008-01-01

183

Was ist Viral Marketing?  

Microsoft Academic Search

Viral Marketing beschreibt das gezielte Auslösen von Mundpropaganda zum Zwecke der Vermarktung von Unternehmen und deren Leistungen.\\u000a Viral Marketing baut auf den Forschungsergebnissen unterschiedlicher Wissenschaftszweige wie etwa der Psychologie, der Sozialwissenschaften\\u000a oder der Evolutionstheorie auf und integriert Erfahrungen der unternehmerischen Praxis. Dadurch entstand in den letzten Jahren\\u000a ein Arsenal an Strategien und Taktiken zur Planung, Durchführung und Erfolgsmessung von Marketingaktionen,

Sascha Langner

184

Viral myelitis: An update  

Microsoft Academic Search

Viral infections of the central nervous system are uncommon but are important in the differential diagnosis of acute myelopathy.\\u000a Acute viral myelitis can present as acute flaccid paralysis (poliomyelitis) or neurologic dysfunction due to involvement of\\u000a the white matter. The latter usually affects only part of the transverse expanse of the spinal cord and manifests as asymmetric\\u000a motor and sensory

Octavia Kincaid; Howard L. Lipton

2006-01-01

185

Hypothesis for heritable, anti-viral immunity in crustaceans and insects  

Microsoft Academic Search

BACKGROUND: It is known that crustaceans and insects can persistently carry one or more viral pathogens at low levels, without signs of disease. They may transmit them to their offspring or to naïve individuals, often with lethal consequences. The underlying molecular mechanisms have not been elucidated, but the process has been called viral accommodation. Since tolerance to one virus does

Timothy W Flegel; Klong Luang

2009-01-01

186

Evaluation of Potential Indicators of Viral Contamination in Shellfish and Their Applicability to Diverse Geographical Areas  

Microsoft Academic Search

The distribution of the concentration of potential indicators of fecal viral pollution in shellfish was analyzed under diverse conditions over 18 months in diverse geographical areas. These microorganisms have been evaluated in relation to contamination by human viral pathogens detected in parallel in the analyzed shellfish samples. Thus, significant shellfish-growing areas from diverse countries in the north and south of

M. Formiga-Cruz; A. K. Allard; A.-C. Conden-Hansson; K. Henshilwood; B. E. Hernroth; J. Jofre; D. N. Lees; F. Lucena; M. Papapetropoulou; R. E. Rangdale; A. Tsibouxi; A. Vantarakis; R. Girones

2003-01-01

187

Radiographic patterns and viral studies in childhood pneumonia at various ages  

Microsoft Academic Search

We aimed at evaluating the relationship between microbial, etiology and chest radiograph appearance in various types of pneumonia. In a prospective study, the radiographic findings in 479 cases of acute pneumonia in children were compared with viral etiology and growth of potential bacterial pathogens in nasopharyngeal secretion. As the basis for viral etiology was most conclusive, the material was here

H. Wahlgren; W. Mortensson; M. Eriksson; Y. Finkel; M. Forsgren

1995-01-01

188

Viral safety of B-domain deleted recombinant factor VIII.  

PubMed

The possible transmission of blood-borne pathogens has been the impetus behind the development of recombinant products formulated in the absence of human-derived components. The viral safety of Chinese hamster ovary (CHO)-cell-based pharmaceuticals is well established. Over 100 million infusions have been administered without a single known incident of CHO-related viral transmission. The manufacturing process for B-domain deleted recombinant factor VIII (BDDrFVIII) builds on this safety record by using a state-of-the-art multitiered approach to viral safety. This approach includes: (1) extensive testing of the CHO cells used to produce BDDrFVIII; (2) routine viral monitoring of the cell culture production process; (3) a purification process in which a specific viral inactivation procedure has been included; (4) a final formulation that does not incorporate human albumin as the stabilizer; and (5) a thorough validation of the viral inactivation and removal capacity of the purification process. This multifaceted viral safety program offers the hemophilia community a factor VIII product with an exceptional degree of viral safety. PMID:11449333

Charlebois, T S; O'connell, B D; Adamson, S R; Brink-Nilsson, H; Jernberg, M; Eriksson, B; Kelley, B D

2001-04-01

189

Viral Hepatitis Transmission in Ambulatory Health Care Settings  

Microsoft Academic Search

In the United States, transmission of viral hepatitis from health care-related exposures is uncommon and primarily recognized in the context of outbreaks. Transmission is typically associated with unsafe injection practices, as exemplified by several recent outbreaks that occurred in ambulatory health care settings. To prevent transmission of bloodborne pathogens, health care workers must adhere to standard precautions and follow fundamental

I. T. Williams; J. F. Perz; B. P. Bell

2004-01-01

190

Viral and host proteins involved in picornavirus life cycle  

Microsoft Academic Search

Picornaviruses cause several diseases, not only in humans but also in various animal hosts. For instance, human enteroviruses can cause hand-foot-and-mouth disease, herpangina, myocarditis, acute flaccid paralysis, acute hemorrhagic conjunctivitis, severe neurological complications, including brainstem encephalitis, meningitis and poliomyelitis, and even death. The interaction between the virus and the host is important for viral replication, virulence and pathogenicity. This article

Jing-Yi Lin; Tzu-Chun Chen; Kuo-Feng Weng; Shih-Cheng Chang; Li-Lien Chen; Shin-Ru Shih

2009-01-01

191

AndreGratia: A Forerunner in Microbial and Viral Genetics  

Microsoft Academic Search

riophages in connection with the study of viruses and cell biology; and (e) unknown aspects of lysogeny and When people spoke of microbes in the early 1900s, colicinogeny described long ago and possibly connected they were thinking almost exclusively of bacterial (and with new findings on imprinting in bacteria. viral) pathogens affecting humans. Of course, Antonie Microbiology has undeniably played

James F. Crow; William F. Dove; Jean-Pierre Gratia

192

Bacterial pathogens.  

PubMed

Bacterial infections are frequent complications among patients treated for cancer. The type, severity, and treatment of bacterial infections vary and depend upon the specific malignancy, associated chemotherapies, and transplantation. This chapter discusses commonly encountered bacterial pathogens as well as Nocardia and mycobacteria in patients with cancer and addresses the clinical syndromes and management. Drug-resistant bacteria are becoming an increasingly recognized problem in patients with cancer. Antimicrobial resistance in select gram-positive and gram-negative bacteria are discussed along with the mechanisms of resistance and recommended therapies. PMID:24706222

Wilson, John W

2014-01-01

193

Autophagy, antiviral immunity, and viral countermeasures  

PubMed Central

The autophagy pathway likely evolved not only to maintain cellular and tissue homeostasis but also to protect cells against microbial attack. This conserved mechanism by which cytoplasmic cargo is delivered to the endolysosomal system is now recognized as a central player in coordinating the host response to diverse intracellular pathogens, including viruses. As an endolysosomal delivery system, autophagy functions in the transfer of viruses from the cytoplasm to the lysosome where they are degraded, in the transfer of viral nucleic acids to endosomal sensors for the activation of innate immunity, and in the transfer of endogenous viral antigens to MHC class II compartments for the activation of adaptive immunity. Viruses have, in turn, evolved different strategies to antagonize, and potentially, to exploit the host autophagic machinery. Moreover, through mechanisms not yet well understood, autophagy may dampen host innate immune and inflammatory responses to viral infection. This review highlights the roles of autophagy in antiviral immunity, viral strategies to evade autophagy, and potential negative feedback functions of autophagy in the host antiviral response.

Shoji-Kawata, Sanae; Levine, Beth

2009-01-01

194

Analysis of host genetic diversity and viral entry as sources of between-host variation in viral load  

PubMed Central

Little is known about the factors that drive the high levels of between-host variation in pathogen burden that are frequently observed in viral infections. Here, two factors thought to impact viral load variability, host genetic diversity and stochastic processes linked with viral entry into the host, were examined. This work was conducted with the aquatic vertebrate virus, Infectious hematopoietic necrosis virus (IHNV), in its natural host, rainbow trout. It was found that in controlled in vivo infections of IHNV, a suggestive trend of reduced between-fish viral load variation was observed in a clonal population of isogenic trout compared to a genetically diverse population of out-bred trout. However, this trend was not statistically significant for any of the four viral genotypes examined, and high levels of fish-to-fish variation persisted even in the isogenic trout population. A decrease in fish-to-fish viral load variation was also observed in virus injection challenges that bypassed the host entry step, compared to fish exposed to the virus through the natural water-borne immersion route of infection. This trend was significant for three of the four virus genotypes examined and suggests host entry may play a role in viral load variability. However, high levels of viral load variation also remained in the injection challenges. Together, these results indicate that although host genetic diversity and viral entry may play some role in between-fish viral load variation, they are not major factors. Other biological and non-biological parameters that may influence viral load variation are discussed.

Wargo, Andrew R.; Kell, Alison M.; Scott, Robert J.; Thorgaard, Gary H.; Kurath, Gael

2012-01-01

195

Antibody-based resistance to plant pathogens.  

PubMed

Plant diseases are a major threat to the world food supply, as up to 15% of production is lost to pathogens. In the past, disease control and the generation of resistant plant lines protected against viral, bacterial or fungal pathogens, was achieved using conventional breeding based on crossings, mutant screenings and backcrossing. Many approaches in this field have failed or the resistance obtained has been rapidly broken by the pathogens. Recent advances in molecular biotechnology have made it possible to obtain and to modify genes that are useful for generating disease resistant crops. Several strategies, including expression of pathogen-derived sequences or anti-pathogenic agents, have been developed to engineer improved pathogen resistance in transgenic plants. Antibody-based resistance is a novel strategy for generating transgenic plants resistant to pathogens. Decades ago it was shown that polyclonal and monoclonal antibodies can neutralize viruses, bacteria and selected fungi. This approach has been improved recently by the development of recombinant antibodies (rAbs). Crop resistance can be engineered by the expression of pathogen-specific antibodies, antibody fragments or antibody fusion proteins. The advantages of this approach are that rAbs can be engineered against almost any target molecule, and it has been demonstrated that expression of functional pathogen-specific rAbs in plants confers effective pathogen protection. The efficacy of antibody-based resistance was first shown for plant viruses and its application to other plant pathogens is becoming more established. However, successful use of antibodies to generate plant pathogen resistance relies on appropriate target selection, careful antibody design, efficient antibody expression, stability and targeting to appropriate cellular compartments. PMID:11252378

Schillberg, S; Zimmermann, S; Zhang, M Y; Fischer, R

2001-01-01

196

Aptasensors for detection of microbial and viral pathogens  

Microsoft Academic Search

Aptamers are specific nucleic acid sequences that can bind to a wide range of non-nucleic acid targets with high affinity and specificity. These molecules are identified and selected through an in vitro process called SELEX (systematic evolution of ligands by exponential enrichment). Proteins are the most common targets in aptamer selection. In diagnostic and detection assays, aptamers represent an alternative

Edith Torres-Chavolla; Evangelyn C. Alocilja

2009-01-01

197

Potential viral pathogenic mechanism for new variant inflammatory bowel disease  

Microsoft Academic Search

Aims: A new form of inflammatory bowel disease (ileocolonic lymphonodular hyperplasia) has been described in a cohort of children with developmental disorder. This study investigates the presence of persistent measles virus in the intestinal tissue of these patients (new variant inflammatory bowel disease) and a series of controls by molecular analysis. Methods: Formalin fixed, paraffin wax embedded and fresh frozen

V Uhlmann; C M Martin; O Sheils; L Pilkington; I Silva; A Killalea; S B Murch; A J Wakefield; J J O'Leary

2002-01-01

198

The Diagnosis of Viral Respiratory Disease in Older Adults  

PubMed Central

Viral respiratory disease in older adults has been increasingly recognized as a significant cause of hospitalizations and death. Unfortunately, the recognition and diagnosis of infection due to many viral respiratory pathogens in older adults can be elusive due to atypical clinical presentations and the insensitivity of current laboratory diagnostic tests in this population. For influenza diagnosis, rapid antigen tests followed by viral culture if negative, can be useful in older adults as long as clinicians are mindful of test limitations. Although specific, rapid antigen tests are insensitive in this population. Erroneous negative results may lead to delays in timely administration of antiviral treatment and institution of appropriate isolation precautions. The increasing availability of new rapid and sensitive molecular diagnostics such as polymerase chain reaction testing, should provide more accurate and timely diagnoses of viral respiratory infections in older adults in the near future.

Talbot, H. Keipp; Falsey, Ann R.

2009-01-01

199

Black leaf streak and viral leaf streak: New banana diseases in East Africa  

Microsoft Academic Search

Black leaf streak, caused by Mycosphaerella fijiensis a virulent pathogen of bananas and plantains, is recorded from Zanzibar. This is the first record of this important pathogen from East Africa. Viral leaf streak of bananas is also identified from Zanzibar. The presence of panama disease and high infestations of root nematode are also noted.

A. J. Dabek; J. M. Waller

1990-01-01

200

A Case History of Adaptive Management Strategies for Viral Hemorrhagic Septicemia Virus (VHSV) in Washington State  

Microsoft Academic Search

We examined nearly 10 years of data and management decisions that have been collected or made by agencies in the Pacific Northwest since the first isolation in North America of a fish pathogen identified as viral hemorrhagic septicemia virus (VHSV). This historical perspective illustrates the problems of managing pathogens in ecosystems that are not self-contained. The responses of management agencies

Kevin Amos; Joan Thomas; Kathleen Hopper

1998-01-01

201

Exotic emerging viral diseases: progress and challenges.  

PubMed

The agents causing viral hemorrhagic fever (VHF) are a taxonomically diverse group of viruses that may share commonalities in the process whereby they produce systemic and frequently fatal disease. Significant progress has been made in understanding the biology of the Ebola virus, one of the best known examples. This knowledge has guided our thinking about other VHF agents, including Marburg, Lassa, the South American arenaviruses, yellow fever, Crimean-Congo and Rift Valley fever viruses. Comparisons among VHFs show that a common pathogenic feature is their ability to disable the host immune response by attacking and manipulating the cells that initiate the antiviral response. Of equal importance, these comparisons highlight critical gaps in our knowledge of these pathogens. PMID:15577929

Geisbert, Thomas W; Jahrling, Peter B

2004-12-01

202

[Viral hepatitis--trends].  

PubMed

Viral hepatitis is a serious health problem all over the world. The aim of the study is to present the actual achievements in the therapeutically field and the general knowledge concerning the subject. Are presented the etiological agents of the acute and chronic hepatitis with the focus on hepatitis B and C, which has become a priority of WHO, with an incidence of the diseases of 360 billion/year for hepatitis B and an sub estimated level for C hepatitis. The most used drugs are presented and the therapeutical combination meant to decrease biological and virusological markers (ALAT, viral load) and to ameliorate the histological aspects of the liver. In conclusion, acute and chronic viral hepatitis represents a challenge for epidemiologists who try to stop the spread of the disease, but also for the infectious diseases specialists and gastroenterologists. PMID:20700962

Manciuc, Carmen; Dorob??, Carmen; Filip-Ciubotaru, Florina-Mihaela

2010-01-01

203

KSHV Rta Promoter Specification and Viral Reactivation  

PubMed Central

Viruses are obligate intracellular pathogens whose biological success depends upon replication and packaging of viral genomes, and transmission of progeny viruses to new hosts. The biological success of herpesviruses is enhanced by their ability to reproduce their genomes without producing progeny viruses or killing the host cells, a process called latency. Latency permits a herpesvirus to remain undetected in its animal host for decades while maintaining the potential to reactivate, or switch, to a productive life cycle when host conditions are conducive to generating viral progeny. Direct interactions between many host and viral molecules are implicated in controlling herpesviral reactivation, suggesting complex biological networks that control the decision. One viral protein that is necessary and sufficient to switch latent Kaposi’s sarcoma-associated herpesvirus (KSHV) into the lytic infection cycle is called K-Rta. K-Rta is a transcriptional activator that specifies promoters by binding DNA directly and interacting with cellular proteins. Among these cellular proteins, binding of K-Rta to RBP-Jk is essential for viral reactivation. In contrast to the canonical model for Notch signaling, RBP-Jk is not uniformly and constitutively bound to the latent KSHV genome, but rather is recruited to DNA by interactions with K-Rta. Stimulation of RBP-Jk DNA binding requires high affinity binding of Rta to repetitive and palindromic “CANT DNA repeats” in promoters, and formation of ternary complexes with RBP-Jk. However, while K-Rta expression is necessary for initiating KSHV reactivation, K-Rta’s role as the switch is inefficient. Many factors modulate K-Rta’s function, suggesting that KSHV reactivation can be significantly regulated post-Rta expression and challenging the notion that herpesviral reactivation is bistable. This review analyzes rapidly evolving research on KSHV K-Rta to consider the role of K-Rta promoter specification in regulating the progression of KSHV reactivation.

Guito, Jonathan; Lukac, David M.

2011-01-01

204

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

205

Evolving viral marketing strategies  

Microsoft Academic Search

One method of viral marketing involves seeding certain consumers within a population to encourage faster adoption of the product throughout the entire population. However, determining how many and which consumers within a particular social network should be seeded to maximize adoption is challenging. We define a strategy space for consumer seeding by weighting a combination of network characteristics such as

Forrest Stonedahl; William Rand; Uri Wilensky

2010-01-01

206

Defensins in Viral Infections  

Microsoft Academic Search

Defensins are antimicrobial peptides important to innate host defense. In addition to their direct antimicrobial effect, defensins modulate immune responses. Increasing evidence indicates that defensins exhibit complex functions by positively or negatively modulating infections of both enveloped and non-enveloped viruses. The effects of defensins on viral infections appear to be specific to the defensin, virus and target cell. Regulation of

Jian Ding; Yi-Ying Chou; Theresa L. Chang

2009-01-01

207

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

2013-10-01

208

Virally Inspired: Gen Y Attitudes Towards Viral Stealth Marketing  

Microsoft Academic Search

The increasing use of viral stealth marketing as a contemporary marketing technique is not well represented in empirical research, particularly in examining consumers' attitudes towards the ethics and effectiveness of viral stealth marketing. Capitalizing on the efficacy of the electronic medium, viral stealth marketing seeks to disguise the relationship between the individual(s) conveying the message and the organisation endorsing it.

Celeste Swanepoel; Ashley Lye; Robert Rugimbana

209

Keloids: A viral hypothesis.  

PubMed

The triggering cause of keloid formation on a healing wound remains an enigma. In fact, the hypotheses put forward so far to explain this phenomenon seem inconsistent with some clinical features of the disease. The recently established bonds between infectious agents and some pathologies of unknown origin such as peptic ulcer disease, Kaposi's sarcoma or cervical cancer among others led us to consider a potential infectious origin for keloids. This paper presents an infection-based hypothesis (specifically, a viral hypothesis) intended to account for most of their clinical features. Essentially, we hypothesize that healthy individuals carrying a virus, whether known or unknown, associated to some adjuvant, and having some genetic susceptibility, may develop keloids during the scar maturation process in the following manner: the virus would make the bone marrow or lymphatic system its reservoir, residing there in a silent state, and reach the wound via two different mechanisms. The primary mechanism might use an internal circuit through which the viral genome would be transported from its myeloid reservoir to the wound via bone marrow or circulating fibrocytes chemotactically attracted to the damaged skin region. The secondary mechanism might involve an external circuit by which infecting virions via saliva would be shed in the wound directly (preferentially in the sternal or deltoid region) or indirectly (other satellite regions) via the hands or some fomites. A combination of both mechanisms might also be possible. Once in the wound, the virus would switch from a silent state to a latent state by effect of some chemical stimulus probably generated during the tissue repair process; in the new state, the transcription of some of the powerful viral proteins might cause thorough derailment of the normal repair process. As a result, keloid growth might depend both on individual susceptibility and on the viral load deposited into the wound; the greater the susceptibility and viral load were, the more markedly the keloid would develop and the more aggressive it would be. PMID:17509771

Alonso, Pedro E; Rioja, Luis F; Pera, Carlos

2008-01-01

210

Tunicamycin Enhances Neuroinvasion and Pathogenicity in Mice with Venezuelan Equine Encephalitis Virus.  

National Technical Information Service (NTIS)

Venezuelan equine encephalitis (VEE) virus infects horses and humans and is a potential biothreat pathogen. Agents that alter the blood-brain barrier (BBB) may enhance viral encephalitides. The current studies explored whether tunicamycin (TM) and other a...

K. E. Steele

2003-01-01

211

Viral Interferon Regulatory Factors  

PubMed Central

Upon viral infection, the major defensive strategy employed by the host immune system is the activation of the interferon (IFN)-mediated antiviral pathway, which is overseen by IFN regulatory factors (IRFs). In order to complete their life cycles, viruses must find a way to modulate the host IFN-mediated immune response. Kaposi's sarcoma-associated herpesvirus (KSHV), a human tumor-inducing herpesvirus, has developed a unique mechanism for antagonizing cellular IFN-mediated antiviral activity by incorporating viral homolog of the cellular IRFs, called vIRFs, into its genome. Here, we summarize the novel evasion mechanisms by which KSHV, through its vIRFs, circumvents IFN-mediated innate immune responses and deregulates the cell growth control mechanism.

Kim, Myung Hee; Lee, Jong-Soo; Liang, Chengyu; Jung, Jae U.

2009-01-01

212

Viral interferon regulatory factors.  

PubMed

Upon viral infection, the major defensive strategy employed by the host immune system is the activation of the interferon (IFN)-mediated antiviral pathway, which is overseen by IFN regulatory factors (IRFs). In order to complete their life cycles, viruses must find a way to modulate the host IFN-mediated immune response. Kaposi's sarcoma-associated herpesvirus (KSHV), a human tumor-inducing herpesvirus, has developed a unique mechanism for antagonizing cellular IFN-mediated antiviral activity by incorporating viral homolog of the cellular IRFs, called vIRFs, into its genome. Here, we summarize the novel evasion mechanisms by which KSHV, through its vIRFs, circumvents IFN-mediated innate immune responses and deregulates the cell growth control mechanism. PMID:19715458

Lee, Hye-Ra; Kim, Myung Hee; Lee, Jong-Soo; Liang, Chengyu; Jung, Jae U

2009-09-01

213

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

214

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

215

Identification of Upper Respiratory Tract Pathogens Using Electrochemical Detection on an Oligonucleotide Microarray  

Microsoft Academic Search

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

Michael J. Lodes; Dominic Suciu; Jodi L. Wilmoth; Marty Ross; Sandra Munro; Kim Dix; Karen Bernards; Axel G. Stöver; Miguel Quintana; Naomi Iihoshi; Wanda J. Lyon; David L. Danley; Andrew McShea; Maurizio Del Poeta

2007-01-01

216

Viral entry mechanisms: the increasing diversity of paramyxovirus entry  

PubMed Central

The paramyxovirus family contains established human pathogens such as measles virus and human respiratory syncytial virus, and emerging pathogens including the Hendra and Nipah viruses and the recently identified human metapneumovirus. Two major envelope glycoproteins, the attachment protein and the fusion protein, promote the processes of viral attachment and virus-cell membrane fusion required for entry. While common mechanisms of fusion protein proteolytic activation and the mechanism of membrane fusion promotion have been shown in recent years, considerable diversity exists in the family related to receptor binding and the potential mechanisms of fusion triggering.

Smith, Everett Clinton; Popa, Andreea; Chang, Andres; Masante, Cyril; Dutch, Rebecca Ellis

2009-01-01

217

Coagulation, protease-activated receptors, and viral myocarditis.  

PubMed

The coagulation protease cascade plays an essential role in hemostasis. In addition, a clot contributes to host defense by limiting the spread of pathogens. Coagulation proteases induce intracellular signaling by cleavage of cell surface receptors called protease-activated receptors (PARs). These receptors allow cells to sense changes in the extracellular environment, such as infection. Viruses activate the coagulation cascade by inducing tissue factor expression and by disrupting the endothelium. Virus infection of the heart can cause myocarditis, cardiac remodeling, and heart failure. A recent study using a mouse model have shown that tissue factor, thrombin, and PAR-1 signaling all positively regulate the innate immune during viral myocarditis. In contrast, PAR-2 signaling was found to inhibit interferon-? expression and the innate immune response. These observations suggest that anticoagulants may impair the innate immune response to viral infection and that inhibition of PAR-2 may be a new strategy to reduce viral myocarditis. PMID:24203054

Antoniak, Silvio; Mackman, Nigel

2014-03-01

218

Informing the Front Line about Common Respiratory Viral Epidemics  

PubMed Central

The nature of clinical medicine is to focus on individuals rather than the populations from which they originate. This orientation can be problematic in the context of acute healthcare delivery during routine winter outbreaks of viral respiratory disease where an individual’s likelihood of viral infection depends on knowledge of local disease incidence. The level of interest in and perceived utility of community and regional infection data for front line clinicians providing acute care is unclear. Based on input from clinicians, we developed an automated analysis and reporting system that delivers pathogen-specific epidemic curves derived from a viral panel that tests for influenza, RSV, adenovirus, parainfluenza and human metapneumovirus. Surveillance summaries were actively e-mailed to clinicians practicing in emergency, urgent and primary care settings and posted on a web site for passive consumption. We demonstrated the feasibility and sustainability of a system that provides both timely and clinically useful surveillance information.

Gesteland, Per H; Samore, Matthew H; Pavia, Andrew T; Srivastava, Rajendu; Korgenski, Kent; Gerber, Kristine; Daly, Judy A; Mundorff, Michael B; Rolfs, Robert T; James, Brent C.; Byington, Carrie L.

2007-01-01

219

Purifying Selection Can Obscure the Ancient Age of Viral Lineages  

PubMed Central

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.

Wertheim, Joel O.; Kosakovsky Pond, Sergei L.

2011-01-01

220

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

221

Animal migration and risk of spread of viral infections: Chapter 9  

USGS Publications Warehouse

The potential contribution of migration towards the spread of disease is as varied as the ecology of the pathogens themselves and their host populations. This chapter outlines multiple examples of viral diseases in animal populations and their mechanisms of viral spread. Many species of insects, mammals, fish, and birds exhibit migratory behavior and have the potential to disperse diseases over long distances. The majority of studies available on viral zoonoses have focused on birds and bats, due to their highly migratory life histories. A number of studies have reported evidence of changes in the timing of animal migrations in response to climate change. The majority indicate an advancement of spring migration, with few or inconclusive results for fall migration. Predicting the combined effects of climate change on migratory patterns of host species and epidemiology of viral pathogens is complex and not fully realistic.

Prosser, Diann J.; Nagel, Jessica; Takekawa, John Y.

2013-01-01

222

Human viral gastroenteritis.  

PubMed Central

During the last 15 years, several different groups of fastidious viruses that are responsible for a large proportion of acute viral gastroenteritis cases have been discovered by the electron microscopic examination of stool specimens. This disease is one of the most prevalent and serious clinical syndromes seen around the world, especially in children. Rotaviruses, in the family Reoviridae, and fastidious fecal adenoviruses account for much of the viral gastroenteritis in infants and young children, whereas the small caliciviruses and unclassified astroviruses, and possibly enteric coronaviruses, are responsible for significantly fewer cases overall. In addition to electron microscopy, enzyme immunoassays and other rapid antigen detection systems have been developed to detect rotaviruses and fastidious fecal adenoviruses in the stool specimens of both nonhospitalized patients and those hospitalized for dehydration and electrolyte imbalance. Experimental rotavirus vaccines have also been developed, due to the prevalence and seriousness of rotavirus infection. The small, unclassified Norwalk virus and morphologically similar viruses are responsible for large and small outbreaks of acute gastroenteritis in older children, adolescents, and adults. Hospitalization of older patients infected with these viruses is usually not required, and their laboratory diagnoses have been limited primarily to research laboratories. Images

Christensen, M L

1989-01-01

223

PATHOGENS: VIEWS OF EPA'S PATHOGEN EQUIVALENCY COMMITTEE  

EPA Science Inventory

This presentation reviews the pathogenic microorganisms that may be found in municipal sewage sludge and the commonly employed Class A and B processes for controlling pathogens. It notes how extensively they are used and discusses issues and concerns with their application. Pre...

224

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

225

Using a Resequencing Microarray as a Multiple Respiratory Pathogen Detection Assay  

Microsoft Academic Search

Simultaneous testing for detection of infectious pathogens that cause similar symptoms (e.g., acute respiratory infections) is invaluable for patient treatment, outbreak prevention, and efficient use of antibiotic and antiviral agents. In addition, such testing may provide information regarding possible coinfections or induced secondary infections, such as virally induced bacterial infections. Furthermore, in many cases, detection of a pathogen requires more

Baochuan Lin; Kate M. Blaney; Anthony P. Malanoski; Adam G. Ligler; Joel M. Schnur; David Metzgar; Kevin L. Russell; David A. Stenger

2007-01-01

226

Molecular detection of pathogen DNA in ticks (Acari: Ixodidae): A review  

Microsoft Academic Search

Ticks play an important role in human and veterinary medicine, in particular due to their ability to transmit a wide spectrum of pathogenic micro-organisms of protozoal, rickettsial, bacterial and viral origin. Pathogens in ticks can be identified by conventional methods such as indirect immuno-fluorescence, isolation in cell culture or by using histological staining techniques. However, the advent of the polymerase

O. A. E. Sparagano; M. T. E. P. Allsopp; R. A. Mank; S. G. T. Rijpkema; J. V. Figueroa; F. Jongejan

1999-01-01

227

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

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

Viral Diseases in Zebrafish: What Is Known and Unknown  

PubMed Central

Naturally occurring viral infections have the potential to introduce confounding variability that leads to invalid and misinterpreted data. Whereas the viral diseases of research rodents are well characterized and closely monitored, no naturally occurring viral infections have been characterized for the laboratory zebrafish (Danio rerio), an increasingly important biomedical research model. Despite the ignorance about naturally occurring zebrafish viruses, zebrafish models are rapidly expanding in areas of biomedical research where the confounding effects of unknown infectious agents present a serious concern. In addition, many zebrafish research colonies remain linked to the ornamental (pet) zebrafish trade, which can contribute to the introduction of new pathogens into research colonies, whereas mice used for research are purpose bred, with no introduction of new mice from the pet industry. Identification, characterization, and monitoring of naturally occurring viruses in zebrafish are crucial to the improvement of zebrafish health, the reduction of unwanted variability, and the continued development of the zebrafish as a model organism. This article addresses the importance of identifying and characterizing the viral diseases of zebrafish as the scope of zebrafish models expands into new research areas and also briefly addresses zebrafish susceptibility to experimental viral infection and the utility of the zebrafish as an infection and immunology model.

Crim, Marcus J.; Riley, Lela K.

2013-01-01

230

Autologous Antibody Capture to Enrich Immunogenic Viruses for Viral Discovery  

PubMed Central

Discovery of new viruses has been boosted by novel deep sequencing technologies. Currently, many viruses can be identified by sequencing without knowledge of the pathogenicity of the virus. However, attributing the presence of a virus in patient material to a disease in the patient can be a challenge. One approach to meet this challenge is identification of viral sequences based on enrichment by autologous patient antibody capture. This method facilitates identification of viruses that have provoked an immune response within the patient and may increase the sensitivity of the current virus discovery techniques. To demonstrate the utility of this method, virus discovery deep sequencing (VIDISCA-454) was performed on clinical samples from 19 patients: 13 with a known respiratory viral infection and 6 with a known gastrointestinal viral infection. Patient sera was collected from one to several months after the acute infection phase. Input and antibody capture material was sequenced and enrichment was assessed. In 18 of the 19 patients, viral reads from immunogenic viruses were enriched by antibody capture (ranging between 1.5x to 343x in respiratory material, and 1.4x to 53x in stool). Enriched reads were also determined in an identity independent manner by using a novel algorithm Xcompare. In 16 of the 19 patients, 21% to 100% of the enriched reads were derived from infecting viruses. In conclusion, the technique provides a novel approach to specifically identify immunogenic viral sequences among the bulk of sequences which are usually encountered during virus discovery metagenomics.

Deijs, Martin; Jonkers, Jiri; Verhoeven, Joost T. P.; Ieven, Margareta; Goossens, Herman; de Jong, Menno D.; Berkhout, Ben; Loens, Katherine; Kellam, Paul; Bakker, Margreet; Canuti, Marta; Cotten, Matthew; van der Hoek, Lia

2013-01-01

231

Emerging Escherichia Pathogen  

PubMed Central

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.

Permpalung, Nitipong; Sentochnik, Deborah E.

2013-01-01

232

Determinants of Microbial Pathogenicity.  

National Technical Information Service (NTIS)

The terms of pathogenicity and virulence are synonymous; they mean the capacity to produce disease. To be pathogenic a microorganism must be able to: (1) Infect the mucous surfaces of the respiratory, alimentary or urogenital tracts. Some microbes are int...

H. Smith

1984-01-01

233

Dengue viral infections  

PubMed Central

Dengue viral infections are one of the most important mosquito borne diseases in the world. They may be asymptomatic or may give rise to undifferentiated fever, dengue fever, dengue haemorrhagic fever (DHF), or dengue shock syndrome. Annually, 100 million cases of dengue fever and half a million cases of DHF occur worldwide. Ninety percent of DHF subjects are children less than 15 years of age. At present, dengue is endemic in 112 countries in the world. No vaccine is available for preventing this disease. Early recognition and prompt initiation of appropriate treatment are vital if disease related morbidity and mortality are to be limited. This review outlines aspects of the epidemiology of dengue infections, the dengue virus and its mosquito vector, clinical features and pathogenesis of dengue infections, and the management and control of these infections.

Malavige, G; Fernando, S; Fernando, D; Seneviratne, S

2004-01-01

234

Detection of viral hemorrhagic septicemia virus  

USGS Publications Warehouse

Viral hemorrhagic septicemia virus (VHSV) is considered to be one of the most important viral pathogens of finfish and is listed as reportable by many nations and international organizations (Office International des Epizooties 2006). Prior to 1988, VHSV was thought to be limited to Europe (Wolf 1988; Smail 1999). Subsequently, it was shown that the virus is endemic among many marine and anadromous fish species in both the Pacific and Atlantic Oceans (Meyers and Winton 1995; Skall et al. 2005). Genetic analysis reveals that isolates of VHSV can be divided into four genotypes that generally correlate with geographic location with the North American isolates generally falling into VHSV Genotype IV (Snow et al. 2004). In 2005-2006, reports from the Great Lakes region indicated that wild fish had experienced disease or, in some cases, very large die-offs from VHSV (Elsayed et al. 2006, Lumsden et al. 2007). The new strain from the Great Lakes, now identified as VHSV Genotype IVb, appears most closely related to isolates of VHSV from mortalities that occurred during 2000-2004 in rivers and near-shore areas of New Brunswick and Nova Scotia, Canada (Gagne et al. 2007). The type IVb isolate found in the Great Lakes region is the only strain outside of Europe that has been associated with significant mortality in freshwater species.

Winton, James; Kurath, Gael; Batts, William

2007-01-01

235

An atomistic approach to viral mechanical oscillations  

NASA Astrophysics Data System (ADS)

Viruses are the simplest ``life'' form. These parasites reproduce by borrowing the machinery of their host cell. Many are pathogenic to plants, animals, and humans. Viruses possess an outer protein coat (capsid) that protects its genomic material that resides inside. We have developed a theoretical technique to model the very low frequency mechanical modes of the viral capsid with atomic resolution. The method uses empirical force fields and a mathematical framework borrowed from electronic structure theory for finding low energy states. The low frequency modes can be ``pinged'' with an ultra-short laser pulse and the aim of the light/vibrational coupling is to interfere with the viral life cycle. The theoretical work here is motivated by the recent work of Tsen et al. [2] who have used ultra-short pulsed laser scattering to inactivate viruses. The methodology can be applied to many systems, and the coupled mechanical oscillations of other floppy biomolecules such as a complete ATP binding cassette (ABC transporter) will also be discussed. Co-authors of this work are Dr. Eric Dykeman, Prof. K.-T. Tsen and Daryn Benson. [4pt] [1] E.C. Dykeman et al., Phys. Rev. Lett., 100, 028101 (2008). [0pt] [2] K-T. Tsen et al., J. of Physics -- Cond. Mat. 19, 472201 (2007).

Sankey, Otto F.

2009-03-01

236

Cases Discussion for Viral Marketing  

Microsoft Academic Search

This essay try to introduce Viral Marketing in the form of case, and through analyzing its success or failure, pros or cons, I'll make my effort to find the foothold and risk point in practice. We can see that, to be a kind of network marketing which spread by customers themselves, Viral Marketing has weak controllability and predictability. So when

Min Liu; TianShi Qu

2011-01-01

237

Deep Sequencing to Identify the Causes of Viral Encephalitis  

PubMed Central

Deep sequencing allows for a rapid, accurate characterization of microbial DNA and RNA sequences in many types of samples. Deep sequencing (also called next generation sequencing or NGS) is being developed to assist with the diagnosis of a wide variety of infectious diseases. In this study, seven frozen brain samples from deceased subjects with recent encephalitis were investigated. RNA from each sample was extracted, randomly reverse transcribed and sequenced. The sequence analysis was performed in a blinded fashion and confirmed with pathogen-specific PCR. This analysis successfully identified measles virus sequences in two brain samples and herpes simplex virus type-1 sequences in three brain samples. No pathogen was identified in the other two brain specimens. These results were concordant with pathogen-specific PCR and partially concordant with prior neuropathological examinations, demonstrating that deep sequencing can accurately identify viral infections in frozen brain tissue.

Chan, Benjamin K.; Wilson, Theodore; Fischer, Kael F.; Kriesel, John D.

2014-01-01

238

Evolution of viral genomes: interplay between selection, recombination, and other forces.  

PubMed

RNA viruses evolve very rapidly, often recombine, and are subject to strong host (immune response) and anthropogenic (antiretroviral drugs) selective forces. Given their compact and extensively sequenced genomes, comparative analysis of RNA viral data can provide important insights into the molecular mechanisms of adaptation, pathogenicity, immune evasion, and drug resistance. In this chapter, we present an example-based overview of recent advances in evolutionary models and statistical approaches that enable screening viral alignments for evidence of adaptive change in the presence of recombination, detecting bursts of directional adaptive evolution associated with the phenotypic changes, and detecting of coevolving sites in viral genes. PMID:22399462

Pond, Sergei L Kosakovsky; Murrell, Ben; Poon, Art F Y

2012-01-01

239

Influenza Viral Manipulation of Sphingolipid Metabolism and Signaling to Modulate Host Defense System  

PubMed Central

Viruses attempt to create a distinctive cellular environment to favor viral replication and spread. Recent studies uncovered new functions of the sphingolipid signaling/metabolism during pathogenic virus infections. While sphingolipids such as sphingomyelin and ceramide were reported to influence the entry step of several viruses, sphingolipid-metabolizing enzymes could directly alter viral replication processes. Influenza virus was shown to increase the level of sphingosine kinase (SK) 1 to promote virus propagation. The mechanism involves regulation of intracellular signaling pathways, leading to the amplification of influenza viral RNA synthesis and nuclear export of viral ribonucleoprotein (RNP) complex. However, bovine viral diarrhea virus inhibits SK1 to enhance the efficacy of virus replication, demonstrating the presence of virus-specific strategies for modulation of the sphingolipid system. Therefore, investigating the sphingolipid metabolism and signaling in the context of virus replication could help us design innovative therapeutic approaches to improve human health.

Vijayan, Madhuvanthi; Hahm, Bumsuk

2014-01-01

240

Vascular events in viral hemorrhagic fevers: a comparative study of dengue and hantaviruses.  

PubMed

Viral hemorrhagic diseases are a group of systemic viral infections with worldwide distribution and are significant causes of global mortality and morbidity. The hallmarks of viral hemorrhagic fevers are plasma leakage, thrombocytopenia, coagulopathy and hemorrhagic manifestations. The molecular mechanisms leading to plasma leakage in viral hemorrhagic fevers are not well understood. A common theme has emerged in which a complex interplay between pathogens, host immune response, and endothelial cells leads to the activation of endothelial cells and perturbation of barrier integrity. In this article, two clinically distinct viral hemorrhagic fevers caused by dengue viruses and hantaviruses are discussed to highlight their similarities and differences that may provide insights into the pathogenesis and therapeutic approach. PMID:24623445

Srikiatkhachorn, Anon; Spiropoulou, Christina F

2014-03-01

241

Molecular Basis of Latency in Pathogenic Human Viruses  

NASA Astrophysics Data System (ADS)

Several human viruses are able to latently infect specific target cell populations in vivo. Analysis of the replication cycles of herpes simplex virus, Epstein-Barr virus, and human immunodeficiency virus suggests that the latent infections established by these human pathogens primarily result from a lack of host factors critical for the expression of viral early gene products. The subsequent activation of specific cellular transcription factors in response to extracellular stimuli can induce the expression of these viral regulatory proteins and lead to a burst of lytic viral replication. Latency in these eukaryotic viruses therefore contrasts with latency in bacteriophage, which is maintained primarily by the expression of virally encoded repressors of lytic replication.

Garcia-Blanco, Mariano A.; Cullen, Bryan R.

1991-11-01

242

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

243

A mixed infection in sevenband grouper Epinephelus septemfasciatus affected with viral nervous necrosis (VNN)  

Microsoft Academic Search

Viral nervous necrosis (VNN) of groupers by fish nodavirus is one of the most serious diseases in aquaculture around the world. In the present study, we introduced a mixed infection of fish nodavirus with another filterable pathogen(s) in VNN-affected sevenband grouper of Nagasaki Prefecture, Japan. In challenge tests with the brain-homogenate of VNN-affected grouper, relative percent survival (RPS) of fish

Yuki Kokawa; Ikuo Takami; Toyohiko Nishizawa; Mamoru Yoshimizu

2008-01-01

244

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

245

Molecular basis of host specificity in human pathogenic bacteria  

PubMed Central

Pathogenic bacteria display various levels of host specificity or tropism. While many bacteria can infect a wide range of hosts, certain bacteria have strict host selectivity for humans as obligate human pathogens. Understanding the genetic and molecular basis of host specificity in pathogenic bacteria is important for understanding pathogenic mechanisms, developing better animal models and designing new strategies and therapeutics for the control of microbial diseases. The molecular mechanisms of bacterial host specificity are much less understood than those of viral pathogens, in part due to the complexity of the molecular composition and cellular structure of bacterial cells. However, important progress has been made in identifying and characterizing molecular determinants of bacterial host specificity in the last two decades. It is now clear that the host specificity of bacterial pathogens is determined by multiple molecular interactions between the pathogens and their hosts. Furthermore, certain basic principles regarding the host specificity of bacterial pathogens have emerged from the existing literature. This review focuses on selected human pathogenic bacteria and our current understanding of their host specificity.

Pan, Xiaolei; Yang, Yang; Zhang, Jing-Ren

2014-01-01

246

Viral infection, inflammation and schizophrenia  

PubMed Central

Schizophrenia is a severe neurodevelopmental disorder with genetic and environmental etiologies. Prenatal viral/bacterial infections and inflammation play a major role 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 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 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.

Kneeland, Rachel E.; Fatemi, S. Hossein

2012-01-01

247

Viral triggers for autoimmunity  

PubMed Central

In this review we want to consider some of the requirements for autoimmune disease to develop and how this may be reproduced in animal models. Besides a genetic predisposition, environmental triggering factors seem to play a central role in the etiology of many autoimmune diseases. In theory, a structural similarity or identity between the host and an invading pathogen might cause the immune system of the host to react not only to the pathogen but also to self-components. However, in order for such a process of molecular mimicry to induce autoimmunity the mechanisms of maintaining tolerance or ignorance to the self-components need to be circumvented. Subsequently, in order to advance autoimmunity to overt autoimmune disease the frequency and avidity of autoaggressive lymphocytes has to be of sufficient magnitude. Intuitively, one would assume that tolerance might be stronger to identical structures than to structures that just share a certain degree of similarity. Self-reactive lymphocytes with high-avidity are more likely to be deleted or functionally silenced by central and/or peripheral tolerance mechanisms. Thus, perfect mimicry between identical structures might fail in inducing autoimmunity because of efficient tolerance mechanisms. In contrast, imperfect mimicry between similar but not identical structures might on one hand circumvent tolerance but on the other hand result in the generation of lymphocytes with only low- to intermediate avidity. Here we examine animal models that use the concept of molecular mimicry as a potential mechanism for inducing or accelerating autoimmunity. We focus on the RIP-LCMV model for type 1 diabetes and the novel cytochrome P450 2D6 (CYP2D6) model for autoimmune hepatitis, which use either identical or similar triggering and target antigens.

Christen, Urs; Hintermann, Edith; Holdener, Martin; von Herrath, Matthias G.

2009-01-01

248

DENGUE VIRAL INFECTIONS  

PubMed Central

Dengue viral infections are one of the most important mosquito-borne diseases in the world. Presently dengue is endemic in 112 countries in the world. It has been estimated that almost 100 million cases of dengue fever and half a million cases of dengue hemorrhagic fever (DHF) occur worldwide. An increasing proportion of DHF is in children less than 15 years of age, especially in South East and South Asia. The unique structure of the dengue virus and the pathophysiologic responses of the host, different serotypes, and favorable conditions for vector breeding have led to the virulence and spread of the infections. The manifestations of dengue infections are protean from being asymptomatic to undifferentiated fever, severe dengue infections, and unusual complications. Early recognition and prompt initiation of appropriate supportive treatment are often delayed resulting in unnecessarily high morbidity and mortality. Attempts are underway for the development of a vaccine for preventing the burden of this neglected disease. This review outlines the epidemiology, clinical features, pathophysiologic mechanisms, management, and control of dengue infections.

Gurugama, Padmalal; Garg, Pankaj; Perera, Jennifer; Wijewickrama, Ananda; Seneviratne, Suranjith L

2010-01-01

249

Virally Inspired: Gen Y Perceptions of Viral Stealth Marketing  

Microsoft Academic Search

Viral stealth marketing is electronic promotions presented as word-of-mouth communication. People spreading these messages conceal the fact that they are paid to promote a product. Non-disclosure raises important ethical questions, as well as the practical problem of the consequences of being found out. Two surveys were uploaded to social networking sites, targeted at Gen Y, with one depicting a viral-marketing

Hume Winzar; Celeste Swanepoel; Ashley Lye

250

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

2013-11-01

251

Immunization of Rhesus Macaques with a DNA Prime\\/Modified Vaccinia Virus Ankara Boost Regimen Induces Broad Simian Immunodeficiency Virus (SIV)Specific T-Cell Responses and Reduces Initial Viral Replication but Does Not Prevent Disease Progression following Challenge with Pathogenic SIVmac239  

Microsoft Academic Search

Producing a prophylactic vaccine for human immunodeficiency virus (HIV) has proven to be a challenge. Most biological isolates of HIV are difficult to neutralize, so that conventional subunit-based antibody-inducing vaccines are unlikely to be very effective. In the rhesus macaque model, some protection was afforded by DNA\\/recombinant viral vector vaccines. However, these studies used as the challenge virus SHIV-89.6P, which

Helen Horton; Thorsten U. Vogel; Donald K. Carter; Kathy Vielhuber; Deborah H. Fuller; Tim Shipley; James T. Fuller; Kevin J. Kunstman; Gerd Sutter; David C. Montefiori; Volker Erfle; Ronald C. Desrosiers; Nancy Wilson; Louis J. Picker; Steven M. Wolinsky; Chenxi Wang; David B. Allison; David I. Watkins

2002-01-01

252

Aseptic Meningitis and Viral Myelitis  

PubMed Central

SYNOPSIS Meningitis and myelitis represent common and very infrequent viral infections of the central nervous system (CNS), respectively. Indeed, the number of cases of viral meningitis that occurs annually exceeds the total number of meningitis cases caused by all other etiologies combined. Focal CNS infections, on the other hand, such as occur in the spinal cord with viral myelitis, are much less common and may be confused with non-infectious disorders that cause acute flaccid paralysis (AFP). This chapter will review some of the important clinical features, epidemiology, diagnostic approaches, and management strategies for patients with aseptic meningitis and viral myelitis. Particular focus will be placed on the diseases caused by enteroviruses (EVs), which as a group account for the vast majority of all aseptic meningitis cases as well as many focal infections of the spinal cord.

Irani, David N.

2008-01-01

253

Immunological Reactions in Viral Hepatitis.  

National Technical Information Service (NTIS)

Viral hepatitis sera (VHS) have been shown to possess mitosis-inhibiting (MI) and chromosome damaging (CD) activities on lymphocytes cultured in vitro in presence of phytohemagglutinin. These activities can be perpetuated by serial passage with filtered m...

B. Pernis

1970-01-01

254

HIV/AIDS - Viral Load  

MedlinePLUS Videos and Cool Tools

English - HIV/AIDS-Viral Load Video Audio Handout Terms of Use Close Window This information made possible with support from ... National Library of Medicine For more information on HIV/AIDS see AIDS.gov

255

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

PubMed Central

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 sites along the Moselle River (eastern France). BGM cell culture and integrated cell culture-reverse transcription-PCR DNA enzyme immunoassay were used to determine the presence of pathogenic viral genome (Enterovirus and Norovirus genogroup II [GGII]) and infectious Enterovirus spp. in 90 1-liter samples. No infectious Enterovirus spp. were isolated, but Enterovirus and Norovirus GGII genomes were detected in 38% of the samples. Norovirus GGII genome was mostly detected in winter, whereas Enterovirus genome was mostly detected in summer and fall. Somatic coliphages appeared to be less sensitive to higher river water temperature than thermotolerant coliforms. Furthermore, the number of river water samples positive for pathogenic viral genome increased with increasing concentration of somatic coliphages, whereas coliform concentration was unrelated to viral genome contamination. Consequently somatic coliphages, which are less sensitive to environmental factors than thermotolerant coliforms in river water, would provide a promising tool for assessment of river water quality in terms of fecal and viral pollution.

Skraber, S.; Gassilloud, B.; Gantzer, C.

2004-01-01

256

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

257

Autophagy vitalizes the pathogenicity of pathogenic fungi.  

PubMed

Plant pathogenic fungi utilize a series of complex infection structures, in particular the appressorium, to gain entry to and colonize plant tissue. As a consequence of the accumulation of huge quantities of glycerol in the cell the appressorium generates immense intracellular turgor pressure allowing the penetration peg of the appressorium to penetrate the leaf cuticle. Autophagic processes are ubiquitous in eukaryotic cells and facilitate the bulk degradation of macromolecules and organelles. The study of autophagic processes has been extended from the model yeast Saccharomyces cerevisiae to pathogenic fungi such as the rice blast fungus Magnaporthe oryzae. Significantly, null mutants for the expression of M. oryzae autophagy gene homologs lose their pathogenicity for infection of host plants. Clarification of the functions and network of interactions between the proteins expressed by M. oryzae autophagy genes will lead to a better understanding of the role of autophagy in fungal pathogenesis and help in the development of new strategies for disease control. PMID:22935638

Liu, Xiao-Hong; Gao, Hui-Min; Xu, Fei; Lu, Jian-Ping; Devenish, Rodney J; Lin, Fu-Cheng

2012-10-01

258

Complete Genome Sequence of Viral Hemorrhagic Septicemia Virus Isolated from an Olive Flounder in South Korea  

PubMed Central

Viral hemorrhagic septicemia virus (VHSV) is a seriously problematic pathogen in olive flounder (Paralichthys olivaceus) aquaculture farms in South Korea. Here, we report the complete genome sequence of VHSV which was isolated from spleen and kidney tissues of dead fish at an aquaculture farm in 2005. This genome sequence will be useful for virus diagnostics and in comparative analyses with other virus genotypes.

Kim, Jong-Oh; Kim, Wi-Sik; Nishizawa, Toyohiko

2013-01-01

259

Temperature, Viral Genetics, and the Transmission of West Nile Virus by Culex pipiens Mosquitoes  

Microsoft Academic Search

The distribution and intensity of transmission of vector-borne pathogens can be strongly influenced by the competence of vectors. Vector competence, in turn, can be influenced by temperature and viral genetics. West Nile virus (WNV) was introduced into the United States of America in 1999 and subsequently spread throughout much of the Americas. Previously, we have shown that a novel genotype

A. Marm Kilpatrick; Mark A. Meola; Robin M. Moudy; Laura D. Kramer

2008-01-01

260

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

261

Respiratory dysfunction and proinflammatory chemokines in the pneumonia virus of mice (PVM) model of viral bronchiolitis  

Microsoft Academic Search

We explore relationships linking clinical symptoms, respiratory dysfunction, and local production of proinflammatory chemokines in the pneumonia virus of mice (PVM) model of viral bronchiolitis. With a reduced inoculum of this natural rodent pathogen, we observe virus clearance by day 9, while clinical symptoms and respiratory dysfunction persist through days 14 and 17 postinoculation, respectively. Via microarray and ELISA, we

Cynthia A. Bonville; Nicholas J. Bennett; Melissa Koehnlein; Deborah M. Haines; John A. Ellis; Alfred M. DelVecchio; Helene F. Rosenberg; Joseph B. Domachowske

2006-01-01

262

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

263

Viral nucleic Acid recognition in human nonimmune cells: in vitro systems.  

PubMed

The innate immune system detects viral infections through a variety of receptors that sense the virus via their nucleic acid genome and evokes initial antiviral responses. Nonimmune cells possess pathogen-recognition mechanisms that enable them to respond to virus by the expression of RNA or DNA recognition receptors, thereby initiating the first steps in the host-pathogen interaction and inducing the production of pro-inflammatory and antiviral mediators. To better understand the activation of innate-immune defense mechanisms by nonimmune cells, we describe an experimental procedure that mimics viral infection, using four human nonimmune cell culture models under stimulation with synthetic analogues of RNA and DNA virus. Furthermore, we exemplify two viral infection models using cultured nonimmune cells and hepatitis C virus (HCV) or polyomavirus BK (BKV). In addition, we report the importance of siRNA technique in gene regulation in order to identify specific markers involved in innate antiviral responses in these cells. PMID:24957230

Ribeiro, Andrea; Wörnle, Markus

2014-01-01

264

Bacterial coinfections in children with viral wheezing  

Microsoft Academic Search

Bacterial coinfections occur in respiratory viral infections, but the attack rates and the clinical profile are not clear. The aim of this study was to determine bacterial coinfections in children hospitalized for acute expiratory wheezing with defined viral etiology. A total of 220 children aged 3 months to 16 years were investigated. The viral etiology of wheezing was confirmed by viral culture,

P. Lehtinen; T. Jartti; R. Virkki; T. Vuorinen; M. Leinonen; V. Peltola; A. Ruohola; O. Ruuskanen

2006-01-01

265

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

266

A viral-human interactome based on structural motif-domain interactions captures the human infectome.  

PubMed

Protein interactions between a pathogen and its host are fundamental in the establishment of the pathogen and underline the infection mechanism. In the present work, we developed a single predictive model for building a host-viral interactome based on the identification of structural descriptors from motif-domain interactions of protein complexes deposited in the Protein Data Bank (PDB). The structural descriptors were used for searching, in a database of protein sequences of human and five clinically important viruses; therefore, viral and human proteins sharing a descriptor were predicted as interacting proteins. The analysis of the host-viral interactome allowed to identify a set of new interactions that further explain molecular mechanism associated with viral infections and showed that it was able to capture human proteins already associated to viral infections (human infectome) and non-infectious diseases (human diseasome). The analysis of human proteins targeted by viral proteins in the context of a human interactome showed that their neighbors are enriched in proteins reported with differential expression under infection and disease conditions. It is expected that the findings of this work will contribute to the development of systems biology for infectious diseases, and help guide the rational identification and prioritization of novel drug targets. PMID:23951184

Segura-Cabrera, Aldo; García-Pérez, Carlos A; Guo, Xianwu; Rodríguez-Pérez, Mario A

2013-01-01

267

[Treatment of viral hepatitis].  

PubMed

Chronic forms of viral B,C and D hepatitis and fulminant hepatitis represent a serious healthcare problem. The study deals with the changes in the strategy in treating these diseases. During the chronic active hepatitis caused by the B hepatitis virus, the main aim of treatment is to cease multiplication of viruses, eliminate the clinical symptoms, prevent the development of cirrhosis, or the origin of hepatocellular carcinoma. The authors analyze the possibilities of the application of corticosteroids, viricidal drugs (vidarabin and interferons) and other medicaments (acyclovir, zidovudin, duramin, gancyclovir, chinacrin, and others) besides corticosteroids, interleukin 2 and tymozin from the group of immunomodulators were tested. The testing included the factor stimulating the colonies of granulocytes and myeloblasts and other substances. The therapy of acute protracted B hepatitis by means of interferon still requires controlled studies. Superinfection by D virus in chronic carriers of HBsAG causes chronic hepatitis which quickly leads to the development of cirrhosis. The therapy on basis of alpha interferon decreases the RNA virus D hepatitis serum level and leads to an improvement in the development of chronic hepatitis in half of the patients. Therapy of chronic C hepatitis on basis of corticosteroids is ineffective, and can be dangerous. Acyclovir is proved to be ineffective as well. The open study indicated certain positive results in application of interferon. The fulminant hepatitis can be defined as a development of encephalopathy and a decrease of the prothrombin time to less than 50% in the course of acute hepatitis. The break-point in the therapy of fulminant hepatitis took place in association with the performance of the transplantation of the liver. Impossibility to transplant the liver means that the effect of therapy of fulminant hepatitis is merely of supportive value. Majority of patients die due to neurologic complications, namely unmanageable oedema of the brain. But still, neither the antioedema therapy, e.g. on basis of manitol, as well as by means of corticosteroids, hemodialysis, hemofiltration, plasmapheresis and hemoperfusion, nor the treatment on basis of E1 prostaglandine improved the survival of patients. (Tab. 2, Ref. 82). PMID:8556359

Miguet, J; Hrusovský, S

1995-09-01

268

Viral Infection Is Not Uncommon in Adult Patients with Severe Hospital-Acquired Pneumonia  

PubMed Central

Background Viral pathogens have not generally been regarded as important causes of severe hospital-acquired pneumonia (HAP), except in patients with hematologic malignancy or transplant recipients. We investigated the role and distribution of viruses in adult with severe HAP who required intensive care. Methods From March 2010 to February 2012, adult patients with severe HAP required admission to the intensive care unit (ICU), 28-bed medical ICU in a tertiary care hospital, were prospectively enrolled. Respiratory viruses were detected using multiplex reverse-transcription polymerase chain reaction and/or shell vial culture. Results A total of 262 patients were enrolled and 107 patients (40.8%) underwent bronchoscopic BAL for etiologic diagnosis. One hundred and fifty-six patients (59.5%) had bacterial infections and 59 patients (22.5%) had viral infections. Viruses were detected in BAL fluid specimens of 37 patients (62.7%, 37/59). The most commonly identified viruses were respiratory syncytial virus and parainfluenza virus (both 27.1%, 16/59), followed by rhinovirus (25.4%, 15/59), and influenza virus (16.9%, 10/59). Twenty-one patients (8.0%, 21/262) had bacterial-viral coinfections and Staphylococcus aureus was the most commonly coexisting bacteria (n?=?10). Viral infection in non-immunocompromised patients was not uncommon (11.1%, 16/143), although it was not as frequent as that in immunocompromised patients (36.4%, 43/119). Non-immunocompromised patients were significantly older than immunocompromised patients and had significantly higher rates of underlying chronic obstructive pulmonary disease, tuberculous destroyed lung and chronic kidney disease. The 28 day mortalities of patients with bacterial infections, viral infections and bacterial-viral coinfections were not significantly different (29.5%, 35.6% and 19.0%, respectively; p?=?0.321). Conclusions Viral pathogens are not uncommon in adult patients with severe HAP who required ICU admission. Since viral pathogens may cause severe HAP and could be a potential source of viral transmission, further investigation is required to delineate the role of viral pathogens in severe HAP.

Hong, Hyo-Lim; Hong, Sang-Bum; Ko, Gwang-Beom; Huh, Jin Won; Sung, Heungsup; Do, Kyung-Hyun; Kim, Sung-Han; Lee, Sang-Oh; Kim, Mi-Na; Jeong, Jin-Yong; Lim, Chae-Man; Kim, Yang Soo; Woo, Jun Hee; Koh, Younsuck; Choi, Sang-Ho

2014-01-01

269

Commentary on the Regulation of Viral Proteins in Autophagy Process  

PubMed Central

The ability to subvert intracellular antiviral defenses is necessary for virus to survive as its replication occurs only in the host cells. Viruses have to modulate cellular processes and antiviral mechanisms to their own advantage during the entire virus life cycle. Autophagy plays important roles in cell regulation. Its function is not only to catabolize aggregate proteins and damaged organelles for recycling but also to serve as innate immunity to remove intracellular pathogenic elements such as viruses. Nevertheless, some viruses have evolved to negatively regulate autophagy by inhibiting its formation. Even more, some viruses have employed autophagy to benefit their replication. To date, there are more and more growing evidences uncovering the functions of many viral proteins to regulate autophagy through different cellular pathways. In this review, we will discuss the relationship between viruses and autophagy and summarize the current knowledge on the functions of viral proteins contributing to affect autophagy process.

Cheng, Ching-Yuan; Chi, Pei-I

2014-01-01

270

Cytolytic CD4+ T cells in viral immunity  

PubMed Central

It is generally believed that the role of CD4+ T cells is to coordinate the different arms of the adaptive immune system to shape an effective response against a pathogen and regulate nonessential or deleterious activities. However, a growing body of evidence suggests that effector CD4+ T cells can directly display potent antiviral activity themselves. The presence of cytolytic CD4+ T cells has been demonstrated in the immune response to numerous viral infections in both humans and in animal models and it is likely that they play a critical role in the control of viral replication in vivo. This article describes the current research on virus-specific cytolytic CD4+ T cells, with a focus on HIV-1 infection and the implications that this immune response has for vaccine design.

Soghoian, Damien Z; Streeck, Hendrik

2011-01-01

271

Resequencing Pathogen Microarray (RPM) for prospective detection and identification of emergent pathogen strains and variants  

NASA Astrophysics Data System (ADS)

High-density resequencing microarrays support simultaneous detection and identification of multiple viral and bacterial pathogens. Because detection and identification using RPM is based upon multiple specimen-specific target pathogen gene sequences generated in the individual test, the test results enable both a differential diagnostic analysis and epidemiological tracking of detected pathogen strains and variants from one specimen to the next. The RPM assay enables detection and identification of pathogen sequences that share as little as 80% sequence similarity to prototype target gene sequences represented as detector tiles on the array. This capability enables the RPM to detect and identify previously unknown strains and variants of a detected pathogen, as in sentinel cases associated with an infectious disease outbreak. We illustrate this capability using assay results from testing influenza A virus vaccines configured with strains that were first defined years after the design of the RPM microarray. Results are also presented from RPM-Flu testing of three specimens independently confirmed to the positive for the 2009 Novel H1N1 outbreak strain of influenza virus.

Tibbetts, Clark; Lichanska, Agnieszka M.; Borsuk, Lisa A.; Weslowski, Brian; Morris, Leah M.; Lorence, Matthew C.; Schafer, Klaus O.; Campos, Joseph; Sene, Mohamadou; Myers, Christopher A.; Faix, Dennis; Blair, Patrick J.; Brown, Jason; Metzgar, David

2010-04-01

272

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

273

Evaluation system for an experimental study of low-pathogenic avian influenza virus (H9N2) infection in specific pathogen free chickens using lactic acid bacteria, Lactobacillus plantarum KFCC11389P  

Microsoft Academic Search

In low-pathogenic avian influenza (LPAI) virus, the effects of prophylactic oral administration of Lactobacillus plantarum KFCC11389P on immunity, viral loads and levels of nitric oxide and interferon-? in splenocytes from specific pathogen free (SPF) chickens were investigated. For in vitro screening of the antiviral effect, haemagglutination activities of four different lactic acid bacterial strains by direct contact with virus were

Heeson Chon; Byungryul Choi; Gajin Jeong; Inpil Mo

2008-01-01

274

Emerging foodborne pathogens  

Microsoft Academic Search

The broad spectrum of foodborne infections has changed dramatically over time, as well-established pathogens have been controlled or eliminated, and new ones have emerged. The burden of foodborne disease remains substantial: one in four Americans is estimated to have a significant foodborne illness each year. The majority of these illnesses are not accounted for by known pathogens, so more must

Robert V. Tauxe

2002-01-01

275

BACTERIAL WATERBORNE PATHOGENS  

EPA Science Inventory

Bacterial pathogens are examples of classical etiological agents of waterborne disease. While these agents no longer serve as major threats to U.S. water supplies, they are still important pathogens in areas with substandard sanitation and poor water treatment facilities. In th...

276

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

277

Plant pathogen resistance  

DOEpatents

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

278

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

279

Habitat fragmentation as a result of biotic and abiotic factors controls pathogen transmission throughout a host population.  

PubMed

1. The hypothesis that habitat fragmentation (biotic or abiotic) alters the transmission of disease within a population is explored using field data from a well-studied amphibian-pathogen system. 2. We used the Ambystoma tigrinum-A. tigrinum virus (ATV) model system to show how habitat fragmentation as a result of emergent vegetation and habitat management affects disease transmission dynamics in ponds across a landscape. 3. We quantified variation in ATV infection over time and across the landscape. ATV infection was significantly higher in ponds modified for livestock use (P = 0.032). Disease incidence decreased with increased amounts of emergent vegetation (P < 0.001). These factors appear to control disease transmission by altering the host contact rate and with it disease transmission. 4. A field experiment to test the effect of emergent vegetation on the distribution of larvae in ponds demonstrated a behavioural change in larvae found in sparsely vegetated ponds. Microhabitat choices resulted in larvae being concentrated at the pond edge resulting in a 'halo effect' in sparsely vegetated ponds, whereas larvae in heavily vegetated ponds were distributed more evenly throughout. Microhabitat choice affects the effective density that larvae experience. This 'halo effect' increases contact rates in the shallows of sparsely vegetated ponds and increases the transmission of a directly transmitted pathogen. 5. Despite recurrent epidemics of a lethal Ranavirus in tiger salamanders on the Kaibab Plateau, Arizona, USA, these populations persist. We discuss the implications of our results in the context of density-dependent transmission and homogeneous mixing, two increases key assumptions of epidemiological theory. PMID:18005032

Greer, Amy L; Collins, James P

2008-03-01

280

Pathogen inactivation techniques.  

PubMed

The desire to rid the blood supply of pathogens of all types has led to the development of many technologies aimed at the same goal--eradication of the pathogen(s) without harming the blood cells or generating toxic chemical agents. This is a very ambitious goal, and one that has yet to be achieved. One approach is to shun the 'one size fits all' concept and to target pathogen-reduction agents at the Individual component types. This permits the development of technologies that might be compatible with, for example, plasma products but that would be cytocidal and thus incompatible with platelet concentrates or red blood cell units. The technologies to be discussed include solvent detergent and methylene blue treatments--designed to inactivate plasma components and derivatives; psoralens (S-59--amotosalen) designed to pathogen-reduce units of platelets; and two products aimed at red blood cells, S-303 (a Frale--frangible anchor-linker effector compound) and Inactine (a binary ethyleneimine). A final pathogen-reduction material that might actually allow one material to inactivate all three blood components--riboflavin (vitamin B2)--is also under development. The sites of action of the amotosalen (S-59), the S-303 Frale, Inactine, and riboflavin are all localized in the nucleic acid part of the pathogen. Solvent detergent materials act by dissolving the plasma envelope, thus compromising the integrity of the pathogen membrane and rendering it non-infectious. By disrupting the pathogen's ability to replicate or survive, its infectivity is removed. The degree to which bacteria and viruses are affected by a particular pathogen-reducing technology relates to its Gram-positive or Gram-negative status, to the sporulation characteristics for bacteria, and the presence of lipid or protein envelopes for viruses. Concerns related to photoproducts and other breakdown products of these technologies remain, and the toxicology of pathogen-reduction treatments is a major ongoing area of investigation. Clearly, regulatory agencies have a major role to play in the evaluation of these new technologies. This chapter will cover the several types of pathogen-reduction systems, mechanisms of action, the inactivation efficacy for specific types of pathogens, toxicology of the various systems and the published research and clinical trial data supporting their potential usefulness. Due to the nature of the field, pathogen reduction is a work in progress and this review should be considered as a snapshot in time rather than a clear picture of what the future will bring. PMID:16377551

Pelletier, J P R; Transue, S; Snyder, E L

2006-01-01

281

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

282

PathogenMIPer: a tool for the design of molecular inversion probes to detect multiple pathogens  

PubMed Central

Background Here we describe PathogenMIPer, a software program for designing molecular inversion probe (MIP) oligonucleotides for use in pathogen identification and detection. The software designs unique and specific oligonucleotide probes targeting microbial or other genomes. The tool tailors all probe sequence components (including target-specific sequences, barcode sequences, universal primers and restriction sites) and combines these components into ready-to-order probes for use in a MIP assay. The system can harness the genetic variability available in an entire genome in designing specific probes for the detection of multiple co-infections in a single tube using a MIP assay. Results PathogenMIPer can accept sequence data in FASTA file format, and other parameter inputs from the user through a graphical user interface. It can design MIPs not only for pathogens, but for any genome for use in parallel genomic analyses. The software was validated experimentally by applying it to the detection of human papilloma virus (HPV) as a model system, which is associated with various human malignancies including cervical and skin cancers. Initial tests of laboratory samples using the MIPs developed by the PathogenMIPer to recognize 24 different types of HPVs gave very promising results, detecting even a small viral load of single as well as multiple infections (Akhras et al, personal communication). Conclusion PathogenMIPer is a software for designing molecular inversion probes for detection of multiple target DNAs in a sample using MIP assays. It enables broader use of MIP technology in the detection through genotyping of pathogens that are complex, difficult-to-amplify, or present in multiple subtypes in a sample.

Thiyagarajan, Sreedevi; Karhanek, Miloslav; Akhras, Michael; Davis, Ronald W; Pourmand, Nader

2006-01-01

283

Translating HIV sequences into quantitative fitness landscapes predicts viral vulnerabilities for rational immunogen design  

PubMed Central

Summary A prophylactic or therapeutic vaccine offers the best hope to curb the HIV-AIDS epidemic gripping sub-Saharan Africa, but remains elusive. A major challenge is the extreme viral sequence variability among strains. Systematic means to guide immunogen design for highly variable pathogens like HIV are not available. Using computational models, we have developed an approach to translate available viral sequence data into quantitative landscapes of viral fitness as a function of the amino acid sequences of its constituent proteins. Predictions emerging from our computationally defined landscapes for the proteins of HIV-1 clade B Gag were positively tested against new in vitro fitness measurements, and were consistent with previously defined in vitro measurements and clinical observations. These landscapes chart the peaks and valleys of viral fitness as protein sequences change, and inform the design of immunogens and therapies that can target regions of the virus most vulnerable to selection pressure.

Ferguson, Andrew L.; Mann, Jaclyn K.; Omarjee, Saleha; Ndung'u, Thumbi; Walker, Bruce D.; Chakraborty, Arup K.

2013-01-01

284

Translating HIV sequences into quantitative fitness landscapes predicts viral vulnerabilities for rational immunogen design.  

PubMed

A prophylactic or therapeutic vaccine offers the best hope to curb the HIV-AIDS epidemic gripping sub-Saharan Africa, but it remains elusive. A major challenge is the extreme viral sequence variability among strains. Systematic means to guide immunogen design for highly variable pathogens like HIV are not available. Using computational models, we have developed an approach to translate available viral sequence data into quantitative landscapes of viral fitness as a function of the amino acid sequences of its constituent proteins. Predictions emerging from our computationally defined landscapes for the proteins of HIV-1 clade B Gag were positively tested against new in vitro fitness measurements and were consistent with previously defined in vitro measurements and clinical observations. These landscapes chart the peaks and valleys of viral fitness as protein sequences change and inform the design of immunogens and therapies that can target regions of the virus most vulnerable to selection pressure. PMID:23521886

Ferguson, Andrew L; Mann, Jaclyn K; Omarjee, Saleha; Ndung'u, Thumbi; Walker, Bruce D; Chakraborty, Arup K

2013-03-21

285

Therapeutic antibodies against viral hepatitis.  

PubMed

Antibodies have the potential to be immunotherapeutic agents, used either as stand-alone therapy or as an adjunct for managing chronic viral infection. In addition, antibodies may be used prophylactically in individuals who have been accidentally exposed to hepatitis B virus (HBV) or hepatitis C virus (HCV), or to prevent re-infection of the liver in patients who have undergone liver transplantation. Human monoclonal antibodies to HBV and HCV were generated and their ability to reduce viral load was tested in different animal model systems, the Trimera mouse model and HBV-carrier chimpanzees. These antibodies were further developed and are currently being studied in clinical trials for chronic HBV or HCV and in liver transplant patients. The antibodies were shown to be safe, tolerable and could significantly reduce viral load. Their ability to inhibit HCV re-infection in the transplanted liver is being evaluated. PMID:12772504

Dagan, Shlomo; Eren, Rachel

2003-04-01

286

Emerging viral infections in transplantation.  

PubMed

Viral infections are an important complication of transplantation. The introduction of more potent immunosuppressive agents over the past decade correlates with an increase in the rate of hospitalizations of transplant patients with infections. Specifically, viral infections have emerged as a major source of morbidity and mortality in transplantation. There are several potential intervention strategies in the face of emerging infections and it is likely that the approach will differ depending on the virus in question. These include viral surveillance and pre-emptive therapy, intervention of the transplant community, and policy change at the level of government, blood bank and organ procurement organizations. This review focuses on the emergence of the herpesviruses; HHV-6 and HHV-7. In addition, the issue of virus transmission through organ transplant is addressed with a discussion of West Nile virus and the rabies virus. PMID:17032433

Smith, Jodi M; McDonald, Ruth A

2006-11-01

287

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

288

Cytosolic Viral Sensor RIG-I Is a 5'-Triphosphate-Dependent Translocase on Double-Stranded RNA  

Microsoft Academic Search

Retinoic acid inducible-gene I (RIG-I) is a cytosolic multidomain protein that detects viral RNA and elicits an antiviral immune response. Two N-terminal caspase activation and recruitment domains (CARDs) transmit the signal, and the regulatory domain prevents signaling in the absence of viral RNA. 5'-triphosphate and double-stranded RNA (dsRNA) are two molecular patterns that enable RIG-I to discriminate pathogenic from self-RNA.

Sua Myong; Sheng Cui; Peter V. Cornish; Axel Kirchhofer; Michaela U. Gack; Jae U. Jung; Karl-Peter Hopfner; Taekjip Ha

2009-01-01

289

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

290

Host-Pathogen Interactions  

PubMed Central

The results presented demonstrate that microbial pathogens of plants have the ability to secrete proteins which effectively inhibit an enzyme synthesized by the host; an enzyme whose substrate is a constituent of the cell wall of the pathogen. The system in which this was discovered is the anthracnose-causing fungal pathogen (Colletotrichum lindemuthianum) and its host, the French bean (Phaseolus vulgaris). An endo-?-1, 3-glucanase present in the bean leaves is specifically inhibited by a protein secreted by C. lindemuthianum. The cell walls of C. lindemuthianum are shown to be composed largely of a 1, 3-glucan.

Albersheim, Peter; Valent, Barbara S.

1974-01-01

291

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

292

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

293

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

PubMed

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 viral sequences in semen of honeybee drones suggesting mating as another horizontal and/or vertical route of virus transmission. Since artificial insemination and controlled mating is widely used in honeybee breeding, the impact of our findings for disease transmission is discussed. PMID:16630626

Yue, Constanze; Schröder, Marion; Bienefeld, Kaspar; Genersch, Elke

2006-06-01

294

Epidemiology and Potential Preventative Measures for Viral Infections in Children With Malignancy and Those Undergoing Hematopoietic Cell Transplantation  

PubMed Central

In pediatric patients with malignancy and those receiving hematopoietic stem cell transplants, bacterial and fungal infections have been the focus of fever and neutropenia episodes for decades. However, improved diagnostic capabilities have revealed viral pathogens as a significant cause of morbidity and mortality. Because of limited effective antiviral therapies, prevention of viral infections is paramount. Pre-exposure and post-exposure prophylaxis and antiviral suppressive therapeutic approaches are reviewed. Additionally, infection control practices specific to this patient population are discussed. A comprehensive approach utilizing each of these can be effective at reducing the negative impact of viral infections.

Fisher, Brian T.; Alexander, Sarah; Dvorak, Christopher C.; Zaoutis, Theoklis E.; Zerr, Danielle M.; Sung, Lillian

2012-01-01

295

Viral obesity: fact or fiction?  

PubMed

The aetiology of obesity is multifactorial. An understanding of the contributions of various causal factors is essential for the proper management of obesity. Although it is primarily thought of as a condition brought on by lifestyle choices, recent evidence shows there is a link between obesity and viral infections. Numerous animal models have documented an increased body weight and a number of physiologic changes, including increased insulin sensitivity, increased glucose uptake and decreased leptin secretion that contribute to an increase in body fat in adenovirus-36 infection. Other viral agents associated with increasing obesity in animals included canine distemper virus, rous-associated virus 7, scrapie, Borna disease virus, SMAM-1 and other adenoviruses. This review attempted to determine if viral infection is a possible cause of obesity. Also, this paper discussed mechanisms by which viruses might produce obesity. Based on the evidence presented in this paper, it can be concluded that a link between obesity and viral infections cannot be ruled out. Further epidemiologic studies are needed to establish a causal link between the two, and determine if these results can be used in future management and prevention of obesity. PMID:19874530

Mitra, A K; Clarke, K

2010-04-01

296

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

297

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

298

Viral Marketing for Multiple Products  

Microsoft Academic Search

Viral Marketing, the idea of exploiting social interactions of users to propagate awareness for products, has gained considerable focus in recent years. One of the key issues in this area is to select the best seeds that maximize the influence propagated in the social network. In this paper, we define the seed selection problem (called t-Influence Maximization, or t-IM) for

Samik Datta; Anirban Majumder; Nisheeth Shrivastava

2010-01-01

299

Recombinant viral vectors: cancer vaccines.  

PubMed

To date cancer vaccines have yet to show efficacy in a phase III trial. However, the clinical benefit seen with monoclonal antibody mediated therapies (e.g., Herceptin) has provided proof of principle that immune responses directed against tumour-associated antigens could have therapeutic potential. The failure of past cancer vaccine trials is likely due to several factors including the inappropriate choice of tumour antigen, use of an unoptimised antigen delivery system or vaccination schedule or selection of the wrong patient group. Any one of these variables could potentially result in the induction of an immune response of insufficient magnitude to deliver clinical benefit. Live recombinant viral vaccines have been used in the development of cancer immunotherapy approaches for the past 10 years. Though such vectors are self-adjuvanted and offer the ability to express multiple tumour-associated antigens (TAAs) along with an array of immune co-factors, arguably, they have yet to demonstrate convincing efficacy in pivotal clinical trials. However, in recent years, more coordinated studies have revealed mechanisms to optimise current vectors and have lead to the development of new advantageous vector systems. In this review, we highlight that live recombinant viral vectors provide a versatile and effective antigen delivery system and describe the optimal properties of an effective viral vector. Additionally, we discuss the advantages and disadvantages of the panel of recombinant viral systems currently available to cancer vaccinologists and how they can work in synergy in heterologous prime boost protocols and with other treatment modalities. PMID:17030074

Harrop, Richard; John, Justin; Carroll, Miles W

2006-10-01

300

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

301

Prevention of Viral Respiratory Infections.  

National Technical Information Service (NTIS)

A study of the incidence and etiology (viral and mycoplasmal) of croup, bronchiolitis and pneumonia was initiated. The study group is a population of nearly 8,000 children 5 years and under. Two hundred and eighteen cases were recorded in the first 2 1/2 ...

J. T. Grayston

1967-01-01

302

Emerging roles of pathogens in Alzheimer disease.  

PubMed

Chronic spirochetal infection can cause slowly progressive dementia, cortical atrophy and amyloid deposition in the atrophic form of general paresis. There is a significant association between Alzheimer disease (AD) and various types of spirochete (including the periodontal pathogen Treponemas and Borrelia burgdorferi), and other pathogens such as Chlamydophyla pneumoniae and herpes simplex virus type-1 (HSV-1). Exposure of mammalian neuronal and glial cells and organotypic cultures to spirochetes reproduces the biological and pathological hallmarks of AD. Senile-plaque-like beta amyloid (A?) deposits are also observed in mice following inhalation of C. pneumoniae in vivo, and A? accumulation and phosphorylation of tau is induced in neurons by HSV-1 in vitro and in vivo. Specific bacterial ligands, and bacterial and viral DNA and RNA all increase the expression of proinflammatory molecules, which activates the innate and adaptive immune systems. Evasion of pathogens from destruction by the host immune reactions leads to persistent infection, chronic inflammation, neuronal destruction and A? deposition. A? has been shown to be a pore-forming antimicrobial peptide, indicating that A? accumulation might be a response to infection. Global attention and action is needed to support this emerging field of research because dementia might be prevented by combined antibiotic, antiviral and anti-inflammatory therapy. PMID:21933454

Miklossy, Judith

2011-01-01

303

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

304

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

305

Pathogenesis and transmissibility of highly (H7N1) and low (H7N9) pathogenic avian influenza virus infection in red-legged partridge (Alectoris rufa)  

Microsoft Academic Search

An experimental infection with highly pathogenic avian influenza virus (HPAIV) and low pathogenic avian influenza virus (LPAIV) was carried out in red-legged partridges (Alectoris rufa) in order to study clinical signs, gross and microscopic lesions, and viral distribution in tissues and viral shedding. Birds were infected with a HPAIV subtype H7N1 (A\\/Chicken\\/Italy\\/5093\\/1999) and a LPAIV subtype H7N9 (A\\/Anas crecca\\/Spain\\/1460\\/2008). Uninoculated

Kateri Bertran; Elisa Pérez-Ramírez; Núria Busquets; Roser Dolz; Antonio Ramis; Ayub Darji; Francesc Xavier Abad; Rosa Valle; Aida Chaves; Júlia Vergara-Alert; Marta Barral; Ursula Höfle; Natàlia Majó

2011-01-01

306

Differential Contribution of PB1-F2 to the Virulence of Highly Pathogenic H5N1 Influenza A Virus in Mammalian and Avian Species  

Microsoft Academic Search

Highly pathogenic avian influenza A viruses (HPAIV) of the H5N1 subtype occasionally transmit from birds to humans and can cause severe systemic infections in both hosts. PB1-F2 is an alternative translation product of the viral PB1 segment that was initially characterized as a pro-apoptotic mitochondrial viral pathogenicity factor. A full-length PB1-F2 has been present in all human influenza pandemic virus

Mirco Schmolke; Balaji Manicassamy; Lindomar Pena; Troy Sutton; Rong Hai; Zsuzsanna T. Varga; Benjamin G. Hale; John Steel; Daniel R. Pérez; Adolfo García-Sastre

2011-01-01

307

Host Phylogeny Determines Viral Persistence and Replication in Novel Hosts  

PubMed Central

Pathogens switching to new hosts can result in the emergence of new infectious diseases, and determining which species are likely to be sources of such host shifts is essential to understanding disease threats to both humans and wildlife. However, the factors that determine whether a pathogen can infect a novel host are poorly understood. We have examined the ability of three host-specific RNA-viruses (Drosophila sigma viruses from the family Rhabdoviridae) to persist and replicate in 51 different species of Drosophilidae. Using a novel analytical approach we found that the host phylogeny could explain most of the variation in viral replication and persistence between different host species. This effect is partly driven by viruses reaching a higher titre in those novel hosts most closely related to the original host. However, there is also a strong effect of host phylogeny that is independent of the distance from the original host, with viral titres being similar in groups of related hosts. Most of this effect could be explained by variation in general susceptibility to all three sigma viruses, as there is a strong phylogenetic correlation in the titres of the three viruses. These results suggest that the source of new emerging diseases may often be predictable from the host phylogeny, but that the effect may be more complex than simply causing most host shifts to occur between closely related hosts.

Longdon, Ben; Hadfield, Jarrod D.; Webster, Claire L.

2011-01-01

308

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

309

Elevated th17 response in infants undergoing respiratory viral infection.  

PubMed

IL-17 and T-helper (Th)17 cells contribute to viral airway pathology in human newborns. Because umbilical cord blood T cells fail to differentiate toward the Th17 lineage in the presence of autologous antigen-presenting cells, we asked whether Th17 cells are present in young infants that experience respiratory viral infection. To this end, we analyzed tracheal aspirate samples from infant patients suffering from acute respiratory syncytial virus (RSV) infection and healthy infant controls. Acute RSV infection associates with elevated IL-17 and accumulation of CD161(+) T cells in acute RSV infected lungs. Correspondingly, local Th17 polarizing cytokines were increased. In peripheral blood, we show that Th17 cells are absent in healthy 1-month-old infants, but are present in acute RSV patients. The triggering of pathogen-associated pattern receptors TLR4 and TLR7 promotes the generation of a Th17-polarizing cytokine environment by 1-month-old infant dendritic cell (DC). We thus conclude that although Th17 cells are absent in healthy newborns, Th17 cells are present in peripheral blood and the airways of infants that experience viral infection, thereby contributing to airway immunopathology. PMID:24650560

Stoppelenburg, Arie J; de Roock, Sytze; Hennus, Marije P; Bont, Louis; Boes, Marianne

2014-05-01

310

Viral Respiratory Infection and the Link to Asthma  

PubMed Central

Viral respiratory infections are closely associated with wheezing illnesses and exacerbations of asthma throughout childhood, and yet there are a number of remaining questions pertaining to the specific nature of this relationship. Infection with an expanding list of respiratory viruses is an important cause of acute wheezing in infancy, and viruses are detected in most exacerbations of asthma throughout childhood. Furthermore, infants who develop severe viral respiratory infections are more likely to have asthma later in childhood. There has been progress in understanding the pathogenesis of viral respiratory illnesses, and this has led to new insights into how these processes might differ in asthma. Several host factors, including respiratory allergy and virus-induced interferon responses, modify the risk of virus-induced wheezing. In the absence of effective antiviral therapies, treatment of virus-induced wheezing and exacerbations of asthma can be challenging, and studies evaluating current treatment strategies are reviewed. Understanding the host-pathogen interactions that determine the severity of respiratory illnesses and long-term sequelae is likely to be of great help in identifying at-risk individuals, and in designing new and more effective treatments.

Gern, James E.

2014-01-01

311

Molecular mechanisms of viral inhibitors of RIG-I-like receptors  

PubMed Central

Activation of innate immune signaling pathways through cytosolic RIG-I like receptors (RLR) is a critical response that is antagonized by many viruses. A variety of RNA related pathogen associated molecular patterns have been identified and their role in RLR activation has been examined. Recent studies suggest that several virally encoded components that antagonize RLR signaling interact with and inhibit the interferon (IFN)-?/? activation pathway using both RNA-dependent and RNA-independent mechanisms. The structural basis for these RLR inhibitory mechanisms, as well as the multifunctional nature of viral RLR antagonists, is reviewed in the context of recent biochemical and structural studies.

Leung, Daisy W.; Basler, Christopher F.; Amarasinghe, Gaya K.

2012-01-01

312

Evaluating viral marketing: isolating the key criteria  

Microsoft Academic Search

Purpose – There has been little evidence of any work undertaken to measure the effectiveness of viral marketing campaigns. This paper aims to report on research undertaken to determine the key criteria that viral marketing practitioners believe should be used to measure the success of viral marketing campaigns. Design\\/methodology\\/approach – Semi-structured interviews were undertaken with some of the premier web

Danilo Cruz; Chris Fill

2008-01-01

313

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

314

Viral Specific RNAs in Infected Cells  

Microsoft Academic Search

Infection by RNA viruses is followed by the appearance of viral RNA in cells. As well as single and double stranded forms of the viral RNA another viral specific RNA can be found in chicken embryo fibroblast cells infected with the arbovirus Semliki forest virus. This may be concerned in the production of protein specific to this virus.

J. A. Sonnabend; E. M. Martin; E. Mécs

1967-01-01

315

Dynamics of viral hemorrhagic septicemia, viral erythrocytic necrosis and ichthyophoniasis in confined juvenile Pacific herring Clupea pallasii  

USGS Publications Warehouse

Capture of wild, juvenile herring Clupea pallasii from Puget Sound (Washington, USA) and confinement in laboratory tanks resulted in outbreaks of viral hemorrhagic septicemia (VHS), viral erythrocytic necrosis (VEN) and ichthyophoniasis; however, the timing and progression of the 3 diseases differed. The VHS epidemic occurred first, characterized by an initially low infection prevalence that increased quickly with confinement time, peaking at 93 to 98% after confinement for 6 d, then decreasing to negligible levels after 20 d. The VHS outbreak was followed by a VEN epidemic that, within 12 d of confinement, progressed from undetectable levels to 100% infection prevalence with >90% of erythrocytes demonstrating inclusions. The VEN epidemic persisted for 54 d, after which the study was terminated, and was characterized by severe blood dyscrasias including reduction of mean hematocrit from 42 to 6% and replacement of mature erythrocytes with circulating erythroblasts and ghost cells. All fish with ichthyophoniasis at capture died within the first 3 wk of confinement, probably as a result of the multiple stressors associated with capture, transport, confinement, and progression of concomitant viral diseases. The results illustrate the differences in disease ecology and possible synergistic effects of pathogens affecting marine fish and highlight the difficulty in ascribing a single causation to outbreaks of disease among populations of wild fishes. ?? Inter-Research 2006.

Hershberger, P.; Hart, A.; Gregg, J.; Elder, N.; Winton, J.

2006-01-01

316

Caenorhabditis elegans as a model for intracellular pathogen infection.  

PubMed

The genetically tractable nematode Caenorhabditis elegans is a convenient host for studies of pathogen infection. With the recent identification of two types of natural intracellular pathogens of C. elegans, this host now provides the opportunity to examine interactions and defence against intracellular pathogens in a whole-animal model for infection. C. elegans is the natural host for a genus of microsporidia, which comprise a phylum of fungal-related pathogens of widespread importance for agriculture and medicine. More recently, C. elegans has been shown to be a natural host for viruses related to the Nodaviridae family. Both microsporidian and viral pathogens infect the C. elegans intestine, which is composed of cells that share striking similarities to human intestinal epithelial cells. Because C. elegans nematodes are transparent, these infections provide a unique opportunity to visualize differentiated intestinal cells in vivo during the course of intracellular infection. Together, these two natural pathogens of C. elegans provide powerful systems in which to study microbial pathogenesis and host responses to intracellular infection. PMID:23617769

Balla, Keir M; Troemel, Emily R

2013-08-01

317

Caenorhabditis elegans as a model for intracellular pathogen infection  

PubMed Central

Summary The genetically tractable nematode Caenorhabditis elegans is a convenient host for studies of pathogen infection. With the recent identification of two types of natural intracellular pathogens of C. elegans, this host now provides the opportunity to examine interactions and defence against intracellular pathogens in a whole-animal model for infection. C. elegans is the natural host for a genus of microsporidia, which comprise a phylum of fungal-related pathogens of widespread importance for agriculture and medicine. More recently, C. elegans has been shown to be a natural host for viruses related to the Nodaviridae family. Both microsporidian and viral pathogens infect the C. elegans intestine, which is composed of cells that share striking similarities to human intestinal epithelial cells. Because C. elegans nematodes are transparent, these infections provide a unique opportunity to visualize differentiated intestinal cells in vivo during the course of intracellular infection. Together, these two natural pathogens of C. elegans provide powerful systems in which to study microbial pathogenesis and host responses to intracellular infection.

Balla, Keir M.; Troemel, Emily R.

2014-01-01

318

Lactoferrin-derived resistance against plant pathogens in transgenic plants.  

PubMed

Lactoferrin (LF) is a ubiquitous cationic iron-binding milk glycoprotein that contributes to nutrition and exerts a broad-spectrum primary defense against bacteria, fungi, protozoa, and viruses in mammals. These qualities make lactoferrin protein and its antimicrobial motifs highly desirable candidates to be incorporated in plants to impart broad-based resistance against plant pathogens or to economically produce them in bulk quantities for pharmaceutical and nutritional purposes. This study introduced bovine LF (BLF) gene into tobacco ( Nicotiana tabacum var. Xanthi), Arabidopsis ( A. thaliana ) and wheat ( Triticum aestivum ) via Agrobacterium -mediated plant transformation. Transgenic plants or detached leaves exhibited high levels of resistance against the damping-off causing fungal pathogen Rhizoctonia solani and the head blight causing fungal pathogen Fusarium graminearum . LF also imparted resistance to tomato plants against a bacterial pathogen, Ralstonia solanacearum . Similarly, other researchers demonstrated expression of LF and LF-mediated high-quality resistance to several other aggressive fungal and bacterial plant pathogens in transgenic plants and against viral pathogens by foliar applications of LF or its derivatives. Taken together, these studies demonstrated the effectiveness of LF for improving crop quality and its biopharming potentials for pharmaceautical and nutritional applications. PMID:23889215

Lakshman, Dilip K; Natarajan, Savithiry; Mandal, Sudhamoy; Mitra, Amitava

2013-12-01

319

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

320

Neopolyploidy and pathogen resistance  

PubMed Central

Despite the well-documented historical importance of polyploidy, the mechanisms responsible for the establishment and evolutionary success of novel polyploid lineages remain unresolved. One possibility, which has not been previously evaluated theoretically, is that novel polyploid lineages are initially more resistant to pathogens than the diploid progenitor species. Here, we explore this possibility by developing and analysing mathematical models of interactions between newly formed polyploid lineages and their pathogens. We find that for the genetic mechanisms of pathogen resistance with the best empirical support, newly formed polyploid populations of hosts are expected to be more resistant than their diploid progenitors. This effect can be quite strong and, in the case of perennial species with recurrent polyploid formation, may last indefinitely, potentially providing a general explanation for the successful establishment of novel polyploid lineages.

Oswald, Benjamin P; Nuismer, Scott L

2007-01-01

321

Emerging and reemerging pathogens.  

PubMed

From 1973 to 1995, 29 new and reemerging pathogenic microbes were recognized. However, in discussions about emerging infectious diseases, the focus is often on the clinical effects of the host-parasite relationship, rather than the examination of the biology of the pathogen. Many of what we refer to as emerging diseases are characterized better as 'diseases of human progress'. Thus, the aerosolization of water has played an important role in the emergence of Legionella pneumophila infections. New diseases are superimposed on endemic diseases such as diarrhoeal diseases, malaria and tuberculosis. In addition, many pathogens are becoming increasingly resistant to standard antimicrobial drugs, making treatment difficult and in some cases impossible. We summarize our experience on emerging parasitic diseases (primary amoebic meningoencephalitis, respiratory cryptosporidiosis, and diplogonoporiasis), and selected problems of bacterial resistance (MDR tuberculosis caused by Mycobacterium bovis and macrolide-resistance mechanisms of Streptococcus pneumoniae and S. pyogenes). PMID:11091058

Gomez-Lus, R; Clavel, A; Castillo, J; Seral, C; Rubio, C

2000-11-01

322

Viral exanthems in the tropics.  

PubMed

Viral exanthems are a common problem in tropical regions, particularly affecting children. Most exanthems are transient and harmless, but some are potentially very dangerous. Pregnant women and malnourished or immunocompromised infants carry the greatest risk of adverse outcome. In this article, parvovirus B19; dengue and yellow fever; West Nile, Barmah Forest, Marburg, and Ebola viruses, and human herpesviruses; asymmetric periflexural exanthema of childhood; measles; rubella; enteroviruses; Lassa fever; and South American hemorrhagic fevers will be discussed. PMID:17350501

Carneiro, Sueli Coelho da Silva; Cestari, Tania; Allen, Samuel H; Ramos e-Silva, Marcia

2007-01-01

323

Open Source and Viral Marketing  

Microsoft Academic Search

ABSTRACT Global competition on the Internet marketplace requires thorough planning and careful investment of capital. Start-up companies,with a limited budget need to reduce cost wherever feasible. Eliminating license costs by using Open Source Software is a big saving for a company,and viral marketing has become,the number,one option to dynamically create brand awareness. The power of online influence, namely, „word of

John-robert Skrob

324

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

325

The Keystone Pathogen Hypothesis  

PubMed Central

Recent studies have highlighted the importance of the human microbiome in host health and disease. However, for the most part the mechanisms by which the microbiome mediates disease, or protection from it, remain poorly understood. The “keystone pathogen” hypothesis holds that certain low-abundance microbial pathogens can orchestrate inflammatory disease by remodelling a normally benign microbiota into a dysbiotic one. In this Opinion, we critically assess the available literature in support of this hypothesis, which may provide a novel conceptual basis for the development of targeted diagnostic and treatment modalities for complex dysbiotic diseases.

Hajishengallis, George; Darveau, Richard P.; Curtis, Michael A.

2012-01-01

326

Bloodborne Pathogens Program  

NASA Technical Reports Server (NTRS)

The final rule on the Occupational Exposure to Bloodborne Pathogens was published in the Federal Register on Dec. 6, 1991. This Standard, 29 CFR Part 1910.130, is expected to prevent 8,900 hepatitis B infections and nearly 200 deaths a year in healthcare workers in the U.S. The Occupational Medicine and Environmental Health Services at KSC has been planning to implement this standard for several years. Various aspects of this standard and its Bloodborne Pathogens Program at KSC are discussed.

Blasdell, Sharon

1993-01-01

327

Host-pathogen interaction in HIV infection  

PubMed Central

The host pathogen interaction is strikingly complex during HIV infection. While several immune effector mechanisms (i.e., cytotoxic T cells, neutralizing antibodies, NK cells, etc) can play a strong antiviral role in vivo, the virus is remarkably able to evade these responses. In addition, the virus preferentially infects and kills activated memory CD4+ T cells, thus exploiting the host antiviral immune response as a source of new cellular targets for infection. Recent advances in understanding (i) how HIV perturbs the host immune system, (ii) how the immune system fights HIV; and (iii) how HIV disease persists when virus replication is suppressed by antiretroviral drugs may hopefully lead to better prevention and treatment strategies for this deadly viral infection.

Chowdhury, Ankita; Silvestri, Guido

2013-01-01

328

Comparison of the Etiology of Viral Respiratory Illnesses in Inner-City and Suburban Infants  

PubMed Central

Background.?The risk of developing childhood asthma has been linked to the severity and etiology of viral respiratory illnesses in early childhood. Since inner-city infants have unique environmental exposures, we hypothesized that patterns of respiratory viral infections would also be distinct. Methods.?We compared the viral etiology of respiratory illnesses in 2 groups: a cohort of 515 infants from 4 inner-city areas and a cohort of 285 infants from mainly suburban Madison, Wisconsin. Nasal secretions were sampled during periods of respiratory illness and at 1 year of age and were analyzed for viral pathogens by multiplex polymerase chain reaction. Results.?Overall, inner-city infants had lower rates of viral detection. Considering specific viruses, sick urban infants had lower rates of detectable rhinovirus or respiratory syncytial virus infection and higher rates of adenovirus infection. Every urban site had a higher proportion of adenovirus-positive samples associated with illnesses (10%–21%), compared with Madison (6%). Conclusions.?These findings provide evidence that inner-city babies have different patterns of viral respiratory illnesses than babies who grow up in a more suburban location. These findings raise important questions about the etiology of virus-negative illnesses in urban infants and the possibility of long-term consequences of early life infections with adenovirus in this population.

Gern, James E.; Pappas, Tressa; Visness, Cynthia M.; Jaffee, Katy F.; Lemanske, Robert F.; Togias, Alkis; Bloomberg, Gordon R.; Cruikshank, William W.; Lamm, Carin; Tuzova, Marina; Wood, Robert A.; Lee, Wai Ming

2012-01-01

329

Fluorescence instrument for in situ monitoring of viral abundance in water, wastewater and recycled water.  

PubMed

In a world of advanced molecular methods quantifying viruses in water remains one of the most inefficient and costly. Using a general molecular DNA/RNA probe - SYBR Gold combined with differential filtration a fast, cost effective and sensitive method is presented to determine the concentration of viruses in water in situ or on-line. The approach differentiates the nucleotide size fractions that are stained with SYBR Gold to show only those associated with Viral DNA and RNA. There was a linear relationship between the fluorescence maxima for SYBR Gold added to wastewater and viral numbers determined with direct counting using epifluorescent microscopy (r(2)=0.97) and for a range of diverse natural water samples (r(2)=0.86). The method was applied to water from the tropics and Antarctica, marine and freshwater environments where natural viral abundances ranged from 10(6) to 10(8) virusesmL(-1). The method takes into account the background fluorescence that represented 70% of total fluorescence and any auto-fluorescence due to other dissolved organic carbon. While DNAse II lowered the background fluorescence associated with free DNA and RNA it could not be eliminated. The technique presented is suitable for monitoring in situ viral numbers in natural water bodies and engineered water treatment processes. This on-line viral monitoring design has the potential to replace human viral pathogen indicators. PMID:22326275

Pollard, Peter C

2012-04-01

330

New chemical method of viral inactivation for vaccine development based on membrane fusion inhibition.  

PubMed

Membrane fusion is an essential step in the entry of enveloped viruses into their host cells. This process is triggered by conformational changes in viral surface glycoproteins. We have demonstrated previously that modification of vesicular stomatitis virus (VSV) with diethylpyrocarbonate (DEPC) abolished the conformational changes on VSV glycoprotein and the fusion reaction induced by the virus. Moreover, we observed that viral treatment with DEPC inactivates the virus, preserving the conformational integrity of its surface proteins. In the present work, we evaluated the potential use of DEPC as a viral inactivating chemical agent for the development of useful vaccines. Pathogenicity and viral replication in Balb/c mice were abolished by viral treatment with 0.5mM DEPC. In addition, antibodies elicited in mice after intraperitoneal immunization with DEPC-inactivated VSV mixed with adjuvants were able to recognize and neutralize the native virus and efficiently protected animals against the challenge with lethal doses of VSV. These results together suggest that viral inactivation with DEPC seems to be a suitable method for the development of safe vaccines. PMID:17949864

Stauffer, Fausto; De Miranda, Joari; Schechter, Marcos C; Queiroz, Fernando A; Santos, Nathalia O; Alves, Ada M B; Da Poian, Andrea T

2007-11-14

331

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

332

Viral-templated Palladium Nanocatalysts  

NASA Astrophysics Data System (ADS)

Despite recent progress on nanocatalysis, there exist several critical challenges in simple and readily controllable nanocatalyst synthesis including the unpredictable particle growth, deactivation of catalytic activity, cumbersome catalyst recovery and lack of in-situ reaction monitoring. In this dissertation, two novel approaches are presented for the fabrication of viral-templated palladium (Pd) nanocatalysts, and their catalytic activities for dichromate reduction reaction and Suzuki Coupling reaction were thoroughly studied. In the first approach, viral template based bottom-up assembly is employed for the Pd nanocatalyst synthesis in a chip-based format. Specifically, genetically displayed cysteine residues on each coat protein of Tobacco Mosaic Virus (TMV) templates provide precisely spaced thiol functionalities for readily controllable surface assembly and enhanced formation of catalytically active Pd nanoparticles. Catalysts with the chip-based format allow for simple separation and in-situ monitoring of the reaction extent. Thorough examination of synthesis-structure-activity relationship of Pd nanoparticles formed on surface-assembled viral templates shows that Pd nanoparticle size, catalyst loading density and catalytic activity of viral-templated Pd nanocatalysts can be readily controlled simply by tuning the synthesis conditions. The viral-templated Pd nanocatalysts with optimized synthesis conditions are shown to have higher catalytic activity per unit Pd mass than the commercial Pd/C catalysts. Furthermore, tunable and selective surface assembly of TMV biotemplates is exploited to control the loading density and location of Pd nanocatalysts on solid substrates via preferential electroless deposition. In addition, the catalytic activities of surface-assembled TMV-templated Pd nanocatalysts were also investigated for the ligand-free Suzuki Coupling reaction under mild reaction conditions. The chip-based format enables simple catalyst separation and reuse as well as facile product recovery. Reaction condition studies show that the solvent ratio played an important role in the selectivity of the Suzuki reaction, and that a higher water/acetonitrile ratio significantly facilitated the cross-coupling pathway. Meanwhile, in-depth characterizations including Atomic Force Microscopy (AFM), Grazing Incidence Small Angle X-ray Scattering (GISAXS), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and X-ray Photoelectron Spectroscopy (XPS) were carried out for these chip-based viral-templated Pd nanocatalysts. In the second approach, catalytically active TMV-templated Pd nanoparticles are encapsulated in readily exploited polymeric microparticle formats. Specifically, small (1˜2 nm), uniform and highly crystalline palladium (Pd) nanoparticles are spontaneously formed along (TMV) biotemplates without external reducing agents. The as-prepared Pd-TMV complexes are integrated into the hybrid poly(ethylene glycol)(PEG)-based microparticles via replica molding (RM) technique in a simple, robust and highly reproducible manner. The Pd-TMV complex structure was characterized by Transmission Electron Microscopy (TEM). The hybrid Pd-TMV-PEG microparticles are examined to have high catalytic activity, recyclability and stability through dichromate reduction. Combined these findings represent a significant step toward simple, robust, scalable synthesis and fabrication of efficient biotemplate-supported Pd nanocatalysts in readily deployable polymeric formats with high capacity in a well-controlled manner. These two simple, robust and readily controllable approaches for the fabrication of viral-templated Pd nanocatalysts, in both chip-based and hydrogel-encapsulated formats, can be readily extended to a variety of other nano-bio hybrid material synthesis in other catalytic reaction systems.

Yang, Cuixian

333

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

334

Transport and survival of bacterial and viral tracers through submerged-flow constructed wetland and sand-filter system  

Microsoft Academic Search

Untreated or improperly treated wastewater has often been cited as the primary contamination source of groundwater. The use of decentralized wastewater treatment systems has applicability around the world since it obviates the need for extensive infrastructure development and expenditures. The use of a submerged flow constructed wetland (CW) and a sand filter to remove bacterial and viral pathogens from wastewater

Everardo Vega; Bruce Lesikar; Suresh D Pillai

2003-01-01

335

A Nuclear Localization of the Infectious Haematopoietic Necrosis Virus NV Protein Is Necessary for Optimal Viral Growth  

Microsoft Academic Search

The nonvirion (NV) protein of infectious hematopoietic necrosis virus (IHNV) has been previously reported to be essential for efficient growth and pathogenicity of IHNV. However, little is known about the mechanism by which the NV supports the viral growth. In this study, cellular localization of NV and its role in IHNV growth in host cells was investigated. Through transient transfection

Myeong Kyu Choi; Chang Hoon Moon; Myoung Seok Ko; Unn-Hwa Lee; Wha Ja Cho; Seung Ju Cha; Jeong Wan Do; Gang Joon Heo; Soo Geun Jeong; Yoo Sik Hahm; Abdallah Harmache; Michel Bremont; Gael Kurath; Jeong Woo Park

2011-01-01

336

DNA vaccination against virus infection and enhancement of antiviral immunity following consecutive immunization with DNA and viral vectors  

Microsoft Academic Search

Recent demonstrations of the immunogenicity of antigens encoded in DNA plasmids following delivery by various routes have heralded a new era in vaccine development. In this article, we review progress in DNA-based antiviral immunoprophylaxis. Preclinical studies have already established the immunogenicity of DNA plasmids encoding protective antigens from a wide variety of viral pathogens and work published in recent months

Alistair J Ramsay; Kah Hoo Leong; Ian A Ramshaw

1997-01-01

337

Regulatory T cells expressing granzyme B play a critical role in controlling lung inflammation during acute viral infection  

Microsoft Academic Search

The inflammatory response to lung infections must be tightly regulated, enabling pathogen elimination while maintaining crucial gas exchange. Using recently described “depletion of regulatory T cell” (DEREG) mice, we found that selective depletion of regulatory T cells (Tregs) during acute respiratory syncytial virus (RSV) infection enhanced viral clearance but increased weight loss, local cytokine and chemokine release, and T-cell activation

J Loebbermann; H Thornton; L Durant; T Sparwasser; K E Webster; J Sprent; F J Culley; C Johansson; P J Openshaw

2012-01-01

338

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...

339

Actinomycetes as plant pathogens  

Microsoft Academic Search

Biology, taxonomy, pathogenicity and control of plant disease inducing actinomycetes are reviewed. Recent progress in the study of potato, sweet potato, blueberry and fruit and forest tree diseases is illustrated. The role in potato scab pathogenesis of the newly discovered phytotoxins, thaxtomins, is discussed.

Romano Locci

1994-01-01

340

Tickling the TLR7 to cure viral hepatitis  

PubMed Central

Chronic hepatitis B and C are the leading causes of liver disease and liver transplantation worldwide. Ability to mount an effective immune response against both HBV and HCV is associated with spontaneous clearance of both infections, while an inability to do so leads to chronicity of both infections. To mount an effective immune response, both innate and adaptive immune responses must work in tandem. Hence, developing protective immunity to hepatitis viruses is an important goal in order to reduce the global burden of these two infections and prevent development of long-term complications. In this regard, the initial interactions between the pathogen and immune system are pivotal in determining the effectiveness of immune response and subsequent elimination of pathogens. Toll-like receptors (TLRs) are important regulators of innate and adaptive immune responses to various pathogens and are often involved in initiating and augmenting effective antiviral immunity. Immune-based therapeutic strategies that specifically induce type I interferon responses are associated with functional cure for both chronic HBV and HCV infections. Precisely, TLR7 stimulation mediates an endogenous type I interferon response, which is critical in development of a broad, effective and protective immunity against hepatitis viruses. This review focuses on anti-viral strategies that involve targeting TLR7 that may lead to development of protective immunity and eradication of hepatitis B.

2014-01-01

341

Immediate Early Responses of Avian Tracheal Epithelial Cells to Infection with Highly Pathogenic Avian Influenza Virus  

Microsoft Academic Search

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 cells systems (TEC) were developed to study early host responses to AIV infection on TEC. Infection

L. Sarmento; M. Pantin-Jackwood; D. R. Kapczynski; D. E. Swayne; C. L. Afonso

2008-01-01

342

Emerging viral diseases of fish and shrimp.  

PubMed

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. PMID:20409453

Walker, Peter J; Winton, James R

2010-01-01

343

Viral Phosphodiesterases That Antagonize Double-Stranded RNA Signaling to RNase L by Degrading 2-5A.  

PubMed

The host interferon (IFN) antiviral response involves a myriad of diverse biochemical pathways that disrupt virus replication cycles at many different levels. As a result, viruses have acquired and evolved genes that antagonize the host antiviral proteins. IFNs inhibit viral infections in part through the 2',5'-oligoadenylate (2-5A) synthetase (OAS)/RNase L pathway. OAS proteins are pathogen recognition receptors that exist at different basal levels in different cell types and that are IFN inducible. Upon activation by the pathogen-associated molecular pattern viral double-stranded RNA, certain OAS proteins synthesize 2-5A from ATP. 2-5A binds to the antiviral enzyme RNase L causing its dimerization and activation. Recently, disparate RNA viruses, group 2a betacoronaviruses, and group A rotaviruses, have been shown to produce proteins with 2',5'-phosphodiesterase (PDE) activities that eliminate 2-5A thereby evading the antiviral activity of the OAS/RNase L pathway. These viral proteins are members of the eukaryotic-viral LigT-like group of 2H phosphoesterases, so named for the presence of 2 conserved catalytic histidine residues. Here, we will review the biochemistry, biology, and implications of viral and cellular 2',5'-PDEs that degrade 2-5A. In addition, we discuss alternative viral and cellular strategies for limiting the activity of OAS/RNase L. PMID:24905202

Silverman, Robert H; Weiss, Susan R

2014-06-01

344

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

PubMed

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. PMID:21466673

Snow, Michael

2011-01-01

345

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

346

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

347

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

348

The Role of Platelets in the Pathogenesis of Viral Hemorrhagic Fevers  

PubMed Central

Viral hemorrhagic fevers (VHF) are acute zoonotic diseases that, early on, seem to cause platelet destruction or dysfunction. Here we present the four major ways viruses affect platelet development and function and new evidence of molecular factors that are preferentially induced by the more pathogenic members of the families Flaviviridae, Bunyaviridae, Arenaviridae, and Filoviridae. A systematic search was performed through the main medical electronic databases using as parameters all current findings concerning platelets in VHF. Additionally, the review contains information from conference proceedings.

Zapata, Juan C.; Cox, Dermot; Salvato, Maria S.

2014-01-01

349

Microfluidics-based extraction of viral RNA from infected mammalian cells for disposable molecular diagnostics  

Microsoft Academic Search

A disposable plastic microfluidic device capable of extracting viral RNA from complex biological mixtures has been developed as a step towards building low-cost, mass produced molecular diagnostic systems for infectious diseases. The device offers a robust, easy-to-use sample preparation platform for rapid processing of clinical samples for nucleic acid-based diagnostics for pathogens. As a platform model, we have successfully isolated

Arpita Bhattacharyya; Catherine M. Klapperich

2008-01-01

350

Compartmentalization of the gut viral reservoir in HIV1 infected patients  

Microsoft Academic Search

BACKGROUND: Recently there has been an increasing interest and appreciation for the gut as both a viral reservoir as well as an important host-pathogen interface in human immunodefiency virus type 1 (HIV-1) infection. The gut associated lymphoid tissue (GALT) is the largest lymphoid organ infected by HIV-1. In this study we examined if different HIV-1 quasispecies are found in different

Guido van Marle; M John Gill; Dione Kolodka; Leah McManus; Tannika Grant; Deirdre L Church

2007-01-01

351

CL385319 inhibits H5N1 avian influenza A virus infection by blocking viral entry  

Microsoft Academic Search

CL-385319, an N-substituted piperidine, is effective in inhibiting infection of H1-, H2-, and to a lesser extent, H3-typed influenza A viruses by interfering with the fusogenic function of the viral hemagglutinin. Here we show that CL-385319 is effective in inhibiting infection of highly pathogenic H5N1 influenza A virus in Madin-Darby Canine Kidney (MDCK) cells with an IC50 of 27.03±2.54?M. This

Shuwen Liu; Runming Li; Ruitao Zhang; Chris C. S. Chan; Baomin Xi; Zhibo Zhu; Jie Yang; Vincent K. M. Poon; Jie Zhou; Min Chen; Jan Münch; Frank Kirchhoff; Stephan Pleschka; Thomas Haarmann; Ursula Dietrich; Chungen Pan; Lanying Du; Shibo Jiang; Bojian Zheng

2011-01-01

352

Viral and Atypical Bacterial Detection in Acute Respiratory Infection in Children Under Five Years  

PubMed Central

Background Acute respiratory infection (ARI) is a leading cause of morbidity and mortality in children worldwide. This study aimed to determine the viral and atypical bacterial causes of different severities and clinical manifestations of ARI in preschool children from low-income families in North-East Brazil. Methods Clinical/demographic data and nasopharyngeal aspirates (NPA) were prospectively collected from children <5 years presenting with ARI over one year to a paediatric A&E department. Disease severity was grouped according to presence of lower respiratory tract signs, need for hospital admission and need for oxygen. Clinical manifestation of ARI was based on discharge diagnosis from hospital with four conditions predominating: bronchiolitis, pneumonia, episodic viral wheeze/asthma and upper respiratory tract infection. Multiplex PCR was used to detect 17 common respiratory viral and atypical bacterial pathogens in NPA. Findings 407 children with a median age of eight months were recruited. Pathogens were detected in 85·5% samples with co-infection being particularly common (39·5%). Respiratory Syncytial Virus (RSV; 37%), Adenoviruses (AdV; 25%), Rhinoviruses (hRV; 19%), Bocavirus (hBoV; 19%), human Meta-pneumovirus (hMPV; 10%) and Mycoplasma pneumoniae (Mpp; 10%) were most prevalent. Detection and co-infection rates were similar in all severities and clinical manifestations of ARI apart from RSV, which was associated with more severe disease and specifically more severe cases of bronchiolitis, and Mpp, which was associated with more severe cases of pneumonia. Mpp was detected in 17% of children admitted to hospital with pneumonia. Interpretation This study underlines the importance of viral and atypical bacterial pathogens in ARI in pre-school children and highlights the complex epidemiology of these pathogens in this age group. Generally, viruses and atypical bacteria were detected in all severities and clinical manifestations of ARI but RSV and Mpp were associated with more severe cases of bronchiolitis and pneumonia respectively.

Bezerra, Patricia G. M.; Britto, Murilo C. A.; Correia, Jailson B.; Duarte, Maria do Carmo M. B.; Fonceca, Angela M.; Rose, Katie; Hopkins, Mark J.; Cuevas, Luis E.; McNamara, Paul S.

2011-01-01

353

[Is fibromyalgia a viral disease?].  

PubMed

Are viruses responsible for the pain in patients with fibromyalgia? Are viruses the trigger for rheumatoid arthritis? Is chronic fatigue syndrome a viral disease? There are many open questions with few or controversial answers. According to the current state of knowledge on the origin of the pain in fibromyalgia the varied symptomatic of fibromyalgia is triggered by peripheral as well as central mechanisms. Despite the broad spectrum of symptoms the disease is a specific entity which is mainly treated with dual reuptake inhibitors, anticonvulsives, tramadol, selective serotonin reuptake inhibitors, gamma-hydroxybutyrate and dopamine agonists in individually selected combinations. PMID:21698474

Sprott, H

2011-10-01

354

Gene expression profiles in febrile children with defined viral and bacterial infection  

PubMed Central

Viral infections are common causes of fever without an apparent source in young children. Despite absence of bacterial infection, many febrile children are treated with antibiotics. Virus and bacteria interact with different pattern recognition receptors in circulating blood leukocytes, triggering specific host transcriptional programs mediating immune response. Therefore, unique transcriptional signatures may be defined that discriminate viral from bacterial causes of fever without an apparent source. Gene expression microarray analyses were conducted on blood samples from 30 febrile children positive for adenovirus, human herpesvirus 6, or enterovirus infection or with acute bacterial infection and 22 afebrile controls. Blood leukocyte transcriptional profiles clearly distinguished virus-positive febrile children from both virus-negative afebrile controls and afebrile children with the same viruses present in the febrile children. Virus-specific gene expression profiles could be defined. The IFN signaling pathway was uniquely activated in febrile children with viral infection, whereas the integrin signaling pathway was uniquely activated in children with bacterial infection. Transcriptional profiles classified febrile children with viral or bacterial infection with better accuracy than white blood cell count in the blood. Similarly accurate classification was shown with data from an independent study using different microarray platforms. Our results support the paradigm of using host response to define the etiology of childhood infections. This approach could be an important supplement to highly sensitive tests that detect the presence of a possible pathogen but do not address its pathogenic role in the patient being evaluated.

Hu, Xinran; Yu, Jinsheng; Crosby, Seth D.; Storch, Gregory A.

2013-01-01

355

Compartmentalization of the gut viral reservoir in HIV-1 infected patients  

PubMed Central

Background Recently there has been an increasing interest and appreciation for the gut as both a viral reservoir as well as an important host-pathogen interface in human immunodefiency virus type 1 (HIV-1) infection. The gut associated lymphoid tissue (GALT) is the largest lymphoid organ infected by HIV-1. In this study we examined if different HIV-1 quasispecies are found in different parts of the gut of HIV-1 infected individuals. Results Gut biopsies (esophagus, stomach, duodenum and colorectum) were obtained from eight HIV-1 infected preHAART (highly active antiretroviral therapy) patients. HIV-1 Nef and Reverse transcriptase (RT) encoding sequences were obtained through nested PCR amplification from DNA isolated from the gut biopsy tissues. The PCR fragments were cloned and sequenced. The resulting sequences were subjected to various phylogenetic analyses. Expression of the nef gene and viral RNA in the different gut tissues was determined using real-time RT-PCR. Phylogenetic analysis of the Nef protein-encoding region revealed compartmentalization of viral replication in the gut within patients. Viral diversity in both the Nef and RT encoding region varied in different parts of the gut. Moreover, increased nef gene expression (p < 0.05) and higher levels of viral genome were observed in the colorectum (p < 0.05). These differences could reflect an adaptation of HIV-1 to the various tissues. Conclusion Our results indicated that different HIV-1 quasispecies populate different parts of the gut, and that viral replication in the gut is compartmentalized. These observations underscore the importance of the gut as a host-pathogen interface in HIV-1 infection.

van Marle, Guido; Gill, M John; Kolodka, Dione; McManus, Leah; Grant, Tannika; Church, Deirdre L

2007-01-01

356

Live Cell Imaging of Viral Entry  

PubMed Central

Viral entry encompasses the initial steps of infection starting from virion host cell attachment to viral genome release. Given the dynamic interactions between the virus and the host, many questions related to viral entry can be directly addressed by live cell imaging. Recent advances in fluorescent labeling of viral and cellular components, fluorescence microscopy with high sensitivity and spatiotemporal resolution, and image analysis enabled studies of a broad spectrum across many viral entry steps, including virus-receptor interactions, internalization, intracellular transport, genomic release, nuclear transport, and cell-to-cell transmission. Collectively, these live cell imaging studies have not only enriched our understandings of the viral entry mechanisms, but also provided novel insights into basic cellular biology processes.

Sun, Eileen; He, Jiang; Zhuang, Xiaowei

2013-01-01

357

Dendritic Cells in Viral Infections  

Microsoft Academic Search

Antigen presenting cells (APCs) are recognized as key initiators of adaptive immunity, particularly to pathogens, by eliciting\\u000a a rapid and potent immune attack on infected cells. Amongst APCs, dendritic cells (DCs) are specially equipped to initiate\\u000a and regulate immune responses in a manner that depends on signals they receive from microbes and their cellular environment.\\u000a To achieve this, they are

Gabrielle Belz; Adele Mount; Frederick Masson

358

Utilization of zebrafish for intravital study of eukaryotic pathogen-host interactions.  

PubMed

Unique imaging tools and practical advantages have made zebrafish a popular model to investigate in vivo host-pathogen interactions. These studies have uncovered details of the mechanisms involved in several human infections. Until recently, studies using this versatile host were limited to viral and prokaryotic pathogens. Eukaryotic pathogens are a diverse group with a major impact on the human and fish populations. The relationships of eukaryote pathogens with their hosts are complex and many aspects remain obscure. The small and transparent zebrafish, with its conserved immune system and amenability to genetic manipulation, make it an exciting model for quantitative study of the core strategies of eukaryotic pathogens and their hosts. The only thing to do now is realize its potential for advancement of biomedical and aquaculture research. PMID:24491522

Gratacap, Remi L; Wheeler, Robert T

2014-09-01

359

Pathogens use structural mimicry of native host ligands as a mechanism for host receptor engagement.  

PubMed

A pathogen's ability to engage host receptors is a critical determinant of its host range and interspecies transmissibility, key issues for understanding emerging diseases. However, the identification of host receptors, which are also attractive drug targets, remains a major challenge. Our structural bioinformatics studies reveal that both bacterial and viral pathogens have evolved to structurally mimic native host ligands (ligand mimicry), thus enabling engagement of their cognate host receptors. In contrast to the structural homology, amino acid sequence similarity between pathogen molecules and the mimicked host ligands was low. We illustrate the utility of this concept to identify pathogen receptors by delineating receptor tyrosine kinase Axl as a candidate receptor for the polyomavirus SV40. The SV40-Axl interaction was validated, and its participation in the infection process was verified. Our results suggest that ligand mimicry is widespread, and we present a quick tool to screen for pathogen-host receptor interactions. PMID:23870314

Drayman, Nir; Glick, Yair; Ben-nun-shaul, Orly; Zer, Hagit; Zlotnick, Adam; Gerber, Doron; Schueler-Furman, Ora; Oppenheim, Ariella

2013-07-17

360

Mechanical limits of viral capsids  

PubMed Central

We studied the elastic properties and mechanical stability of viral capsids under external force-loading with computer simulations. Our approach allows the implementation of specific geometries corresponding to specific phages, such as ?29 and cowpea chlorotic mottle virus. We demonstrate how, in a combined numerical and experimental approach, the elastic parameters can be determined with high precision. The experimentally observed bimodality of elastic spring constants is shown to be of geometrical origin, namely the presence of pentavalent units in the viral shell. We define a criterion for capsid breakage that explains well the experimentally observed rupture. From our numerics we find a crossover from ?2/3 to ?1/2 for the dependence of the rupture force on the Föppl-von Kármán number, ?. For filled capsids, high internal pressures lead to a stronger destabilization for viruses with buckled ground states versus viruses with unbuckled ground states. Finally, we show how our numerically calculated energy maps can be used to extract information about the strength of protein–protein interactions from rupture experiments.

Buenemann, Mathias; Lenz, Peter

2007-01-01

361

Stochastic models of viral infection  

NASA Astrophysics Data System (ADS)

We develop biophysical models of viral infections from a stochastic process perspective. The entry of enveloped viruses is treated as a stochastic multiple receptor and coreceptor engagement process that can lead to membrane fusion or endocytosis. The probabilities of entry via fusion and endocytosis are computed as functions of the receptor/coreceptor engagement rates. Since membrane fusion and endocytosis entry pathways can lead to very different infection outcomes, we delineate the parameter regimes conducive to each entry pathway. After entry, viral material is biochemically processed and degraded as it is transported towards the nucleus. Productive infections occur only when the material reaches the nucleus in the proper biochemical state. Thus, entry into the nucleus in an infectious state requires the proper timing of the cytoplasmic transport process. We compute the productive infection probability and show its nonmonotonic dependence on both transport speeds and biochemical transformation rates. Our results carry subtle consequences on the dosage and efficacy of antivirals such as reverse transcription inhibitors.

Chou, Tom

2009-03-01

362

Bovine viral diarrhea in a newborn calf.  

PubMed

Bovine viral diarrhea virus was believed to be the cause of ill-thrift since birth, resulting in death of a Holstein calf. Bovine viral diarrhea virus was isolated from Peyer's patches and mesenteric lymph nodes, but serum neutralizing antibodies were not detected. The lymphoid depletion and myeloid suppression seen in this case may be a factor in the immune system dysfunction described for bovine viral diarrhea. Typical ulcerative lesions within the alimentary tract were not observed. PMID:3988595

Lloyd, K C; Morris, D D

1985-03-15

363

Viral Hepatitis-Related Acute Liver Failure  

Microsoft Academic Search

OBJECTIVES:Viral hepatitis has previously been the major cause of acute liver failure (ALF) in the United States. We aimed to determine the incidence of viral hepatitis-related ALF and to compare the outcome and clinical and biochemical variables in patients with hepatitis A and B.METHODS:A total of 354 patients with ALF from multiple centers were screened for possible acute viral etiology.RESULTS:Forty-three

Frank Vinholt Schiødt; Timothy J. Davern; A. Obaid Shakil; Brendan McGuire; Grace Samuel; William M. Lee

2003-01-01

364

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

365

Microtubules and Pathogen Defence  

Microsoft Academic Search

The cytoskeletal network of plant cells represents a dynamic structure that responds to external\\u000a stimuli by changes of organization. An attack of pathogenic microbes represents an external stress that\\u000a seriously threatens plant survival. Growing evidence from recent research indicates that cytoskeletal elements,\\u000a such as microtubules and microfilaments, are central players in plant defence responses. Tubulin and actin\\u000a inhibitors suppress the polarization

Issei Kobayashi; Yuhko Kobayashi

366

Did viral disease of humans wipe out the Neandertals?  

PubMed

Neandertals were an anatomically distinct hominoid species inhabiting a vast geographical area ranging from Portugal to western Siberia and from northern Europe to the Middle East. The species became extinct 28,000 years ago, coinciding with the arrival of anatomically modern humans (AMHs) in Europe 40,000 years ago. There has been considerable debate surrounding the main causes of the extinction of Neandertals. After at least 200,000 years of successful adaption to the climate, flora and fauna of Eurasia, it is not clear why they suddenly failed to survive. For many years, climate change or competition with anatomically modern human (AMH) have been the leading hypotheses. Recently these hypotheses have somewhat fallen out of favour due to the recognition that Neandertals were a highly developed species with complex social structure, culture and technical skills. Were AMHs lucky and survived some catastrophe that eradicated the Neandertals? It seems unlikely that this is the case considering the close timing of the arrival of AMHs and the disappearance of Neandertals. Perhaps the arrival of AMHs also brought additional new non-human microscopic inhabitants to the regions where Neandertals lived and these new inhabitants contributed to the disappearance of the species. We introduce a medical hypothesis that complements other recent explanations for the extinction of Neandertals. After the ancestors of Neandertals left Africa, their immune system adapted gradually to the pathogens in their new Eurasian environment. In contrast, AMHs continued to co-evolve with east African pathogens. More than 200,000 years later, AMHs carried pathogens that would have been alien to pre-historic Europe. First contact between long separated populations can be devastating. Recent European and American history provides evidence for similar events, where introduction of viral, protozoan or bacterial pathogens to immunologically naïve populations lead to mass mortality and local population extinction. We propose that a virus, possibly from the family Herpesviridae, contributed to Neandertal extinction. PMID:20172660

Wolff, Horst; Greenwood, Alex D

2010-07-01

367

Severe viral respiratory infections: are bugs bugging?  

PubMed

Viral respiratory tract infections (RTI) pose a high burden on the youngest members of our society. Several risk factors are known for severe viral respiratory disease. However, a large proportion of the severe RTI cannot be explained by these risk factors. A growing body of evidence shows that the composition of the microbiota has a major influence on the training of both the mucosal and the systemic immune response and can thus potentially determine susceptibility for severe viral infections. In this review, we discuss the current evidence regarding the influence of bacterial colonization on the severity of viral respiratory infections. PMID:24220300

Vissers, M; de Groot, R; Ferwerda, G

2014-03-01

368

Natural Killer Cell Responses to Viral Infection  

PubMed Central

Natural killer (NK) cells, as part of the innate immune system, play a key role in host defense against viral infections. Recent advances have indicated that NK cell activation and function are regulated by the interplay between inhibitory and activating signals. Thus, a better understanding of mechanisms responsible for NK cell activation and function in the control of viral infections will help develop NK cell-based therapies. In this review, we will first discuss how NK cells are activated in response to viral infections. We will then focus on the recruitment of activated NK cells to the site of infection as well as on NK cell effector mechanisms against virally infected cells.

Brandstadter, Joshua D.; Yang, Yiping

2011-01-01

369

Betanodavirus up-regulates chaperone GRP78 via ER stress: roles of GRP78 in viral replication and host mitochondria-mediated cell death  

Microsoft Academic Search

Whether viral pathogens that induce ER stress responses benefit the host or the virus remains controversial. In this study\\u000a we show that betanodavirus induced ER stress responses up-regulate GRP78, which regulates the viral replication and host cellular\\u000a mitochondrial-mediated cell death. Betanodavirus (redspotted grouper nervous necrosis virus, RGNNV) infection resulted in\\u000a the following increased ER stress responses in fish GF-1 grouper

Yu-Chin Su; Jen-Leih Wu; Jiann-Ruey Hong

2011-01-01

370

Viral modulation of cell death by inhibition of caspases.  

PubMed

Caspases are key effectors of the apoptotic process. Some of them play important roles in the immune system, being involved in the proteolytic maturation of the key cytokines, including interleukin 1beta (IL-1beta) and IL-18. The latter directs the production of interferon gamma (IFN-gamma). Among pathogens, particularly viruses express various modulators of caspases that inhibit their activity by direct binding. By evading the apoptotic process, viruses can better control their production in the infected cell and avoid the attack of the immune system. Targeting the maturation of the key cytokines involved in the initiation of (antiviral) immune response helps to avoid recognition and eradication by the immune system. The three main classes of caspase inhibitors frequently found among viruses include serine proteinase inhibitors (serpins: CrmA/SPI-2), viral IAPs (vIAPs) and p35. Their molecular mechanisms of action, structures and overall influence on cellular physiology are discussed in the review below. PMID:12691301

Cassens, Uwe; Lewinski, Grzegorz; Samraj, Ajoy K; von Bernuth, Horst; Baust, Heinrich; Khazaie, Khashayarsha; Los, Marek

2003-01-01

371

(Mechanisms of inhibition of viral replication in plants)  

SciTech Connect

During the last year we have made a number of important observations in the fields of virology and plant molecular biology. By directly sequencing Tomato Mosaic Virus (ToMV) movement genes, previously undetected sequence alterations common to specific viral strains were found. The difficulty in regenerating transgenic tomato plants containing the Tm-2 gene was overcome. Tobacco plants transformed with Cucumber Mosaic Virus (CMV) are being characterized. Analysis of transgenic tobacco plants expressing CMV coat protein have shown no correlation between coat protein expression and level of resistance. Specific amino acid changes have been found to correlate with CMV resistance breaking and degree of pathogenicity. Satellite RNAs are shown to be too unstable for use as a biological control agent. The aphid transmission domain CMV has been localized to one (or more) of three amino acids; constructs have been made to determine the exact amino acids involved. 15 refs.

Not Available

1991-01-01

372

Recruitment of RED-SMU1 Complex by Influenza A Virus RNA Polymerase to Control Viral mRNA Splicing  

PubMed Central

Influenza A viruses are major pathogens in humans and in animals, whose genome consists of eight single-stranded RNA segments of negative polarity. Viral mRNAs are synthesized by the viral RNA-dependent RNA polymerase in the nucleus of infected cells, in close association with the cellular transcriptional machinery. Two proteins essential for viral multiplication, the exportin NS2/NEP and the ion channel protein M2, are produced by splicing of the NS1 and M1 mRNAs, respectively. Here we identify two human spliceosomal factors, RED and SMU1, that control the expression of NS2/NEP and are required for efficient viral multiplication. We provide several lines of evidence that in infected cells, the hetero-trimeric viral polymerase recruits a complex formed by RED and SMU1 through interaction with its PB2 and PB1 subunits. We demonstrate that the splicing of the NS1 viral mRNA is specifically affected in cells depleted of RED or SMU1, leading to a decreased production of the spliced mRNA species NS2, and to a reduced NS2/NS1 protein ratio. In agreement with the exportin function of NS2, these defects impair the transport of newly synthesized viral ribonucleoproteins from the nucleus to the cytoplasm, and strongly reduce the production of infectious influenza virions. Overall, our results unravel a new mechanism of viral subversion of the cellular splicing machinery, by establishing that the human splicing factors RED and SMU1 act jointly as key regulators of influenza virus gene expression. In addition, our data point to a central role of the viral RNA polymerase in coupling transcription and alternative splicing of the viral mRNAs.

Munier, Sandie; Tomoiu, Andru; Demeret, Caroline; Vidalain, Pierre-Olivier; Jacob, Yves; Naffakh, Nadia

2014-01-01

373

PIPS: Pathogenicity Island Prediction Software  

PubMed Central

The adaptability of pathogenic bacteria to hosts is influenced by the genomic plasticity of the bacteria, which can be increased by such mechanisms as horizontal gene transfer. Pathogenicity islands play a major role in this type of gene transfer because they are large, horizontally acquired regions that harbor clusters of virulence genes that mediate the adhesion, colonization, invasion, immune system evasion, and toxigenic properties of the acceptor organism. Currently, pathogenicity islands are mainly identified in silico based on various characteristic features: (1) deviations in codon usage, G+C content or dinucleotide frequency and (2) insertion sequences and/or tRNA genetic flanking regions together with transposase coding genes. Several computational techniques for identifying pathogenicity islands exist. However, most of these techniques are only directed at the detection of horizontally transferred genes and/or the absence of certain genomic regions of the pathogenic bacterium in closely related non-pathogenic species. Here, we present a novel software suite designed for the prediction of pathogenicity islands (pathogenicity island prediction software, or PIPS). In contrast to other existing tools, our approach is capable of utilizing multiple features for pathogenicity island detection in an integrative manner. We show that PIPS provides better accuracy than other available software packages. As an example, we used PIPS to study the veterinary pathogen Corynebacterium pseudotuberculosis, in which we identified seven putative pathogenicity islands.

Soares, Siomar C.; Abreu, Vinicius A. C.; Ramos, Rommel T. J.; Cerdeira, Louise; Silva, Artur; Baumbach, Jan; Trost, Eva; Tauch, Andreas; Hirata, Raphael; Mattos-Guaraldi, Ana L.; Miyoshi, Anderson; Azevedo, Vasco

2012-01-01

374

Viral RNA Silencing Suppressors (RSS): Novel Strategy of Viruses to Ablate the Host RNA Interference (RNAi) Defense System  

PubMed Central

Pathogenic viruses have developed a molecular defense arsenal for their survival by counteracting the host anti-viral system known as RNA interference (RNAi). Cellular RNAi, in addition to regulating gene expression through microRNAs, also serves as a barrier against invasive foreign nucleic acids. RNAi is conserved across the biological species, including plants, animals and invertebrates. Viruses in turn, have evolved mechanisms that can counteract this anti-viral defense of the host. Recent studies of mammalian viruses exhibiting RNA silencing suppressor (RSS) activity have further advanced our understanding of RNAi in terms of host-virus interactions. Viral proteins and non-coding viral RNAs can inhibit the RNAi (miRNA/siRNA) pathway through different mechanisms. Mammalian viruses having dsRNA-binding regions and GW/WG motifs appear to have a high chance of conferring RSS activity. Although, RSSs of plant and invertebrate viruses have been well characterized, mammalian viral RSSs still need in-depth investigations to present the concrete evidences supporting their RNAi ablation characteristics. The information presented in this review together with any perspective research should help to predict and identify the RSS activity-endowed new viral proteins that could be the potential targets for designing novel anti-viral therapeutics.

Bivalkar-Mehla, Shalmali; Vakharia, Janaki; Mehla, Rajeev; Abreha, Measho; Kanwar, Jagat Rakesh; Tikoo, Akshay; Chauhan, Ashok

2010-01-01

375

Occurrence and persistence of bacterial and viral faecal indicators in wastewater biofilms.  

PubMed

Biofilms within wastewater treatment plants can capture enteric microorganisms initially present in the water phase immobilising them either definitively or temporarily. Consequently, fates of microorganisms may totally change depending on whether they interact or not with biofilms. In this study, we assessed the stability of wastewater biofilms comparing the evolution of the concentrations of bacteria (heterotrophic plate count [HPC], thermotolerant coliforms [TC]) and viral (somatic coliphages [SC] and F-specific phages [F +]) indicators in the biofilms and in the corresponding wastewaters at 4 and 20 dgrees C. Additionally, we assessed the monthly occurrence of these bacterial and viral indicators as well as of pathogenic protozoa (Cryptosporidium oocysts and Giardia cysts) in three native wastewater biofilms for four months. Our results show that viral indicators (SC and F + ) persist longer in biofilms than in the corresponding wastewaters at 4 degrees C as well as at 20 degrees C. In contrast, persistence of bacterial indicators (TC and HPC) depends on both the temperature and the matrix. Differences between viral and bacterial persistence are discussed. Monthly analysis of native wastewater biofilms shows that bacterial and viral indicators, as well as Cryptosporidium oocysts and Giardia cysts, attach to wastewater biofilms to a concentration that remains stable in time, probably as a result of a dynamic equilibrium between attachment and detachment processes. PMID:17547008

Skraber, S; Helmi, K; Willame, R; Ferréol, M; Gantzer, C; Hoffmann, L; Cauchie, H M

2007-01-01

376

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

377

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

378

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

379

Congenital Cytomegalovirus Infection: Molecular Mechanisms Mediating Viral Pathogenesis  

PubMed Central

Human cytomegalovirus (CMV) is responsible for approximately 40,000 congenital infections in the United States each year. Congenital CMV disease frequently produces serious neurodevelopmental disability, as well as vision impairment and sensorineural hearing loss. Development of a CMV vaccine is therefore considered to be a major public health priority. The mechanisms by which CMV injures the fetus are complex and likely include a combination of direct fetal injury induced by pathologic virally-encoded gene products, an inability of the maternal immune response to control infection, and the direct impact of infection on placental function. CMV encodes gene products that function, both at the RNA and the protein level, to interfere with many cellular processes. These include gene products that modify the cell cycle; interfere with apoptosis; induce an inflammatory response; mediate vascular injury; induce site-specific breakage of chromosomes; promote oncogenesis; dysregulate cellular proliferation; and facilitate evasion of host immune responses. This minireview summarizes current concepts regarding these aspects of the molecular virology of CMV and the potential pathogenic impact of viral gene expression on the developing fetus. Areas for potential development of novel therapeutic intervention are suggested for improving the outcome of this disabling congenital infection.

Schleiss, Mark R.

2013-01-01

380

Enhancement of Enteric Adenovirus Cultivation by Viral Transactivator Proteins?  

PubMed Central

Human enteric adenoviruses (HAdVs; serotypes 40 and 41) are important waterborne and food-borne pathogens. However, HAdVs are fastidious, are difficult to cultivate, and do not produce a clear cytopathic effect during cell culture within a reasonable time. Thus, we examined whether the viral transactivator proteins cytomegalovirus (CMV) IE1 and hepatitis B virus (HBV) X promoted the multiplication of HAdVs. Additionally, we constructed a new 293 cell line expressing CMV IE1 protein for cultivation assays. We analyzed the nucleic acid sequences of the promoter regions of both E1A and hexon genes, which are considered to be the most important regions for HAdV replication. Expression of either HBV X or CMV IE1 protein significantly increased the promoter activities of E1A and hexon genes of HAdVs by as much as 14-fold during cell cultivation. The promotion of HAdV expression was confirmed by increased levels of both adenoviral DNA and mRNA expression. Finally, the newly developed 293 cell line expressing CMV IE1 protein showed an increase in viral DNA ranging from 574% to 619% compared with the conventional 293 cell line. These results suggest that the newly constructed cell line could be useful for efficient cultivation and research of fastidious HAdVs.

Kim, Misoon; Lim, Mi Young; Ko, GwangPyo

2010-01-01

381

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

382

Bovine viral diarrhea virus infection induces autophagy in MDBK cells.  

PubMed

Bovine viral diarrhea virus (BVDV) is an enveloped, positive-sense, single-stranded RNA virus that belongs to the genus Pestivirus (Flaviviridae). The signaling pathways and levels of signaling molecules are altered in Madin-Darby Bovine Kidney (MDBK) cells infected with BVDV. Autophagy is a conservative biological degradation pathway that mainly eliminates and degrades damaged or superfluous organelles and macromolecular complexes for intracellular recycling in eukaryotic cells. Autophagy can also be induced as an effective response to maintain cellular homeostasis in response to different stresses, such as nutrient or growth factor deprivation, hypoxia, reactive oxygen species exposure and pathogen infection. However, the effects of BVDV infection on autophagy inMDBK cells remain unclear. Therefore, we performed an analysis of autophagic activity after BVDV NADL infection using real-time PCR, electron microscopy, laser confocal microscopy, and Western blotting analysis. The results demonstrated that BVDV NADL infection increased autophagic activity and significantly elevated the expression levels of the autophagy-related genes Beclin1 and ATG14 inMDBK cells. However, the knockdown of Beclin1 and ATG14 by RNA interference (RNAi) did not affect BVDV NADL infection-related autophagic activity. These findings provided a novel perspective to elaborate the effects of viral infection on the host cells. PMID:24972811

Fu, Qiang; Shi, Huijun; Ren, Yan; Guo, Fei; Ni, Wei; Qiao, Jun; Wang, Pengyan; Zhang, Hui; Chen, Chuangfu

2014-07-01

383

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

384

Production and Titering of Recombinant Adeno-associated Viral Vectors  

PubMed Central

In recent years recombinant adeno-associated viral vectors (AAV) have become increasingly valuable for in vivo studies in animals, and are also currently being tested in human clinical trials. Wild-type AAV is a non-pathogenic member of the parvoviridae family and inherently replication-deficient. The broad transduction profile, low immune response as well as the strong and persistent transgene expression achieved with these vectors has made them a popular and versatile tool for in vitro and in vivo gene delivery. rAAVs can be easily and cheaply produced in the laboratory and, based on their favourable safety profile, are generally given a low safety classification. Here, we describe a method for the production and titering of chimeric rAAVs containing the capsid proteins of both AAV1 and AAV2. The use of these so-called chimeric vectors combines the benefits of both parental serotypes such as high titres stocks (AAV1) and purification by affinity chromatography (AAV2). These AAV serotypes are the best studied of all AAV serotypes, and individually have a broad infectivity pattern. The chimeric vectors described here should have the infectious properties of AAV1 and AAV2 and can thus be expected to infect a large range of tissues, including neurons, skeletal muscle, pancreas, kidney among others. The method described here uses heparin column purification, a method believed to give a higher viral titer and cleaner viral preparation than other purification methods, such as centrifugation through a caesium chloride gradient. Additionally, we describe how these vectors can be quickly and easily titered to give accurate reading of the number of infectious particles produced.

Wulff, Peer; Klugmann, Matthias; Murray, Andrew J.

2011-01-01

385

Viral Marketing: Why Do Consumers Forward Content?  

Microsoft Academic Search

Communication technology is expanding at an incredibly rapid pace. Smart phones, tablet computers, and high speed wireless networks are all redefining the paradigm for communication. For marketers this means more avenues to reach potential customers. Viral marketing is one such avenue. Viral marketing is often defined as the modern incarnation of word of mouth marketing. This concept involves getting consumers

Jonathon Hitz

2010-01-01

386

Minimizing Seed Set for Viral Marketing  

Microsoft Academic Search

Viral marketing has attracted considerable concerns in recent years due to its novel idea of leveraging the social network to propagate the awareness of products. Specifically, viral marketing is to first target a limited number of users (seeds) in the social network by providing incentives, and these targeted users would then initiate the process of awareness spread by propagating the

Cheng Long; Raymond Chi-Wing Wong

2011-01-01

387

Pathogenic bacteria as vaccine vectors: teaching old bugs new tricks.  

PubMed

As our scientific knowledge of bacteria grows, so does our ability to manipulate these bacteria to protect rather than infect mammalian hosts from a diverse group of diseases. The old axiom that the best way to protect from a disease is to get infected in the first place is not feasible in the face of the diverse group of pathogens that infect humans. Therefore, reprogramming bacteria to protect against diverse bacterial, viral, and parasitic diseases as well as cancer is a new reality in the field of vaccines. PMID:21165341

Carleton, Heather A

2010-12-01

388

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

389

Prolonged respiratory viral shedding in transplant patients.  

PubMed

Respiratory viral infections are frequent causes of morbidity in transplant patients. We screened symptomatic adult transplant recipients for respiratory viruses in a cohort of patients attending a referral medical center in Brazil. The duration of viral shedding and the prevalence of viral codetections were also determined. During a 1-year period (2011-2012), swabs were obtained from 50 patients. An in-house polymerase chain reaction panel designed to detect 10 viruses was used. Viruses were identified in 19 (38%) patients, particularly parainfluenza III (32%) and the respiratory syncytial virus (20%); multiple viruses were identified in 26% of patients. Prolonged viral shedding was observed with 60% of individuals excreting viruses for >10 days. The clinical and epidemiologic relevance of prolonged viral shedding remains to be determined. PMID:24289829

de Lima, C R A; Mirandolli, T B; Carneiro, L C; Tusset, C; Romer, C M; Andreolla, H F; Baethgen, L F; Pasqualotto, A C

2014-02-01

390

Viral Etiology of Acute Respiratory Infection in Gansu Province, China, 2011  

PubMed Central

Background Acute respiratory infections (ARIs) are the leading cause of children and their leading killer. ARIs are responsible for at least six percent of the world's disability and death. Viruses are one of the most common agents causing ARIs. Few studies on the viral etiology and clinical characteristics of ARIs have been performed in the northwest region of China, including Gansu Province. Methods Clinical and demographic information and throat swabs were collected from 279 patients from January 1st to December 30st, 2011. Multiplex RT-PCR was performed to detect 16 respiratory viral pathogens. Results 279 patients were admitted for ARIs. The patients aged from 1 month to 12 years, with the median age of 2 years. Of which, 105 (37.6%) were positive for at least one pathogen. A total of 136 respiratory viral pathogens were identified from the 105 patients. Respiratory syncytial virus (RSV) was the most frequently detected pathogen (26.5%, 36/136), followed by parainfluenza virus (PIV) 1–3 (22.1%, 30/136), human rhinovirus (HRV) (21.3%, 29/136), human coronavirus (CoV) (10.3%, 14/136) and human adenovirus (HAdV) (9.6%, 13/136). Influenza A (Flu A), human metapneumovirus (hMPV) and human bocavirus (BoCA) were found 4.4%, 3.7% and 2.2%, respectively. Influenza B (Flu B) and seasonal influenza A H1N1(sH1N1) were not detected. Single-infections were detected in 30.5% (85/279) of cases. RSV was the most common pathogens in patients under 1 year and showed seasonal variation with peaks during winter and spring. Conclusions This paper presents data on the epidemiology of viral pathogens associated with ARIs among children in Gansu Province, China. RSV is most frequently detected in our study. The findings could serve as a reference for local CDC in drawing up further plans to prevent and control ARIs.

Mao, Naiying; Zhu, Zhen; Zhang, Hui; Jiang, Zhongyi; Li, Hongyu; Zhang, Yan; Shi, Jing; Zhang, Shuang; Wang, Xinhua; Xu, Wenbo

2013-01-01

391

Do plant and human pathogens have a common pathogenicity strategy?  

Microsoft Academic Search

Recently, a novel ‘two-step’ model of pathogenicity has been described that suggests host-cell-derived vasculoproliferative factors play a crucial role in the pathogenesis of bacillary angiomatosis, a disease caused by the human pathogenic bacterium Bartonella henselae. The resulting proliferation of endothelial cells could be interpreted as bacterial pathogens triggering the promotion of their own habitat: the host cell. Similar disease mechanisms

Volkhard A. J Kempf; Niclas Hitziger; Tanja Riess; Ingo B Autenrieth

2002-01-01

392

Reovirus ?NS Protein Is Required for Nucleation of Viral Assembly Complexes and Formation of Viral Inclusions  

PubMed Central

Progeny virions of mammalian reoviruses are assembled in the cytoplasm of infected cells at discrete sites termed viral inclusions. Studies of temperature-sensitive (ts) mutant viruses indicate that nonstructural protein ?NS and core protein ?2 are required for synthesis of double-stranded (ds) RNA, a process that occurs at sites of viral assembly. We used confocal immunofluorescence microscopy and ts mutant reoviruses to define the roles of ?NS and ?2 in viral inclusion formation. In cells infected with wild-type (wt) reovirus, ?NS and ?2 colocalize to large, perinuclear structures that correspond to viral inclusions. In cells infected at a nonpermissive temperature with ?NS-mutant virus tsE320, ?NS is distributed diffusely in the cytoplasm and ?2 is contained in small, punctate foci that do not resemble viral inclusions. In cells infected at a nonpermissive temperature with ?2-mutant virus tsH11.2, ?2 is distributed diffusely in the cytoplasm and the nucleus. However, ?NS localizes to discrete structures in the cytoplasm that contain other viral proteins and are morphologically indistinguishable from viral inclusions seen in cells infected with wt reovirus. Examination of cells infected with wt reovirus over a time course demonstrates that ?NS precedes ?2 in localization to viral inclusions. These findings suggest that viral RNA-protein complexes containing ?NS nucleate sites of viral replication to which other viral proteins, including ?2, are recruited to commence dsRNA synthesis.

Becker, Michelle M.; Goral, Mehmet I.; Hazelton, Paul R.; Baer, Geoffrey S.; Rodgers, Steven E.; Brown, Earl G.; Coombs, Kevin M.; Dermody, Terence S.

2001-01-01

393

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

394

Cryptosporidium Pathogenicity and Virulence  

PubMed Central

Cryptosporidium is a protozoan parasite of medical and veterinary importance that causes gastroenteritis in a variety of vertebrate hosts. Several studies have reported different degrees of pathogenicity and virulence among Cryptosporidium species and isolates of the same species as well as evidence of variation in host susceptibility to infection. The identification and validation of Cryptosporidium virulence factors have been hindered by the renowned difficulties pertaining to the in vitro culture and genetic manipulation of this parasite. Nevertheless, substantial progress has been made in identifying putative virulence factors for Cryptosporidium. This progress has been accelerated since the publication of the Cryptosporidium parvum and C. hominis genomes, with the characterization of over 25 putative virulence factors identified by using a variety of immunological and molecular techniques and which are proposed to be involved in aspects of host-pathogen interactions from adhesion and locomotion to invasion and proliferation. Progress has also been made in the contribution of host factors that are associated with variations in both the severity and risk of infection. Here we provide a review comprised of the current state of knowledge on Cryptosporidium infectivity, pathogenesis, and transmissibility in light of our contemporary understanding of microbial virulence.

Bouzid, Maha; Chalmers, Rachel M.; Tyler, Kevin M.

2013-01-01

395

Immunization with viral antigens: viral diseases of carp and catfish.  

PubMed

The viral diseases of carp and catfish for which vaccines have been produced are spring viraemia of carp (SVC), grass carp haemorrhage disease (GCHD) and channel catfish virus disease (CCVD). Field trials of a commercially produced injectable vaccine conducted over several years have shown that carp can be protected against SVC. However the supporting data were predominantly qualitative rather than quantitative. Large-scale field trials of an experimental oral attenuated vaccine against SVC virus over a five year period were successful, and no reversion to virulence of the vaccine was recorded. Injectable inactivated and attenuated vaccines against GCHD have predominantly been tested under laboratory conditions, although a small number of field trials have been reported. In such trials of bath and injectable vaccines, survival rates of 50-90% were achieved. In China, commercially available vaccines are being used against GCHD. Only laboratory trials of vaccines against CCVD have been reported. Bath vaccination of eggs of fry with a subunit vaccine and bath immunisation of fingerlings with an attenuated virus vaccine have been successful. Problems with current approaches and areas for research are discussed. PMID:9270851

Dixon, P

1997-01-01

396

Viral Etiology and Clinical Profiles of Children with Severe Acute Respiratory Infections in China  

PubMed Central

Background No comprehensive analysis is available on the viral etiology and clinical characterization among children with severe acute respiratory infection (SARI) in China during 2009 H1N1 pandemic and post-pandemic period. Methods Cohort of 370 hospitalized children (1 to 72 months) with SARI from May 2008 to March 2010 was enrolled in this study. Nasopharyngeal aspirate (NPA) specimens were tested by a commercial assay for 18 respiratory viral targets. The viral distribution and its association with clinical character were statistically analyzed. Results Viral pathogen was detected in 350 (94.29%) of children with SARI. Overall, the most popular viruses were: enterovirus/rhinovirus (EV/RV) (54.05%), respiratory syncytial virus (RSV) (51.08%), human bocavirus (BoCA) (33.78%), human parainfluenzaviruse type 3 (PIV3) (15.41%), and adenovirus (ADV) (12.97%). Pandemic H1N1 was the dominant influenza virus (IFV) but was only detected in 20 (5.41%) of children. Moreover, detection rate of RSV and human metapneumovirus (hMPV) among suburb participants were significantly higher than that of urban area (P<0.05). Incidence of VSARI among suburb participants was also significant higher, especially among those of 24 to 59 months group (P<0.05). Conclusion Piconaviruses (EV/RV) and paramyxoviruses are the most popular viral pathogens among children with SARI in this study. RSV and hMPV significantly increase the risk of SARI, especially in children younger than 24 months. Higher incidence of VSARI and more susceptibilities to RSV and hMPV infections were found in suburban patients.

Lu, Roujian; He, Bin; Liu, Chunyan; Ma, Xuejun; Tan, Wenjie

2013-01-01

397

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

398

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 viral RNA replication, and we identified viral protein 2C as the target of this compound. PMID:23335743

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; van Kuppeveld, Frank J M

2013-04-01

399

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

400

Role of gut pathogens in development of irritable bowel syndrome  

PubMed Central

Acute infectious gastroenteritis is one of the most commonly identifiable risk factors for the development of irritable bowel syndrome (IBS). A number of bacterial, viral and parasitic pathogens have been found to be associated with the development of IBS and other functional gastrointestinal (GI) disorders. Epidemiological studies have identified demographic and acute enteritis-related risk factors for the development of post-infectious-IBS (PI-IBS). Immune dysregulation, alterations in barrier function, serotonergic and mast cell activation have been identified as potential pathophysiological mechanisms. Additionally, variations in host genes involved in barrier function, antigen presentation and cytokine response have been associated with PI-IBS development. However, it is unknown whether specific pathogens have unique effects on long-term alterations in gut physiology or different pathogens converge to cause common alterations resulting in similar phenotype. The role of microbial virulence and pathogenicity factors in development of PI-IBS is also largely unknown. Additionally, alterations in host gut sensation, motility, secretion, and barrier function in PI-IBS need to be elucidated. Finally, both GI infections and antibiotics used to treat these infections can cause long-term alterations in host commensal microbiota. It is plausible that alteration in the commensal microbiome persists in a subset of patients predisposing them to develop PI-IBS.

Grover, Madhusudan

2014-01-01

401

Fungal pathogens of Proteaceae.  

PubMed

Species of Leucadendron, Leucospermum and Protea (Proteaceae) are in high demand for the international floriculture market due to their brightly coloured and textured flowers or bracts. Fungal pathogens, however, create a serious problem in cultivating flawless blooms. The aim of the present study was to characterise several of these pathogens using morphology, culture characteristics, and DNA sequence data of the rRNA-ITS and LSU genes. In some cases additional genes such as TEF 1-? and CHS were also sequenced. Based on the results of this study, several novel species and genera are described. Brunneosphaerella leaf blight is shown to be caused by three species, namely B. jonkershoekensis on Protea repens, B. nitidae sp. nov. on Protea nitida and B. protearum on a wide host range of Protea spp. (South Africa). Coniothyrium-like species associated with Coniothyrium leaf spot are allocated to other genera, namely Curreya grandicipis on Protea grandiceps, and Microsphaeropsis proteae on P. nitida (South Africa). Diaporthe leucospermi is described on Leucospermum sp. (Australia), and Diplodina microsperma newly reported on Protea sp. (New Zealand). Pyrenophora blight is caused by a novel species, Pyrenophora leucospermi, and not Drechslera biseptata or D. dematoidea as previously reported. Fusicladium proteae is described on Protea sp. (South Africa), Pestalotiopsis protearum on Leucospermum cuneiforme (Zimbabwe), Ramularia vizellae and R. stellenboschensis on Protea spp. (South Africa), and Teratosphaeria capensis on Protea spp. (Portugal, South Africa). Aureobasidium leaf spot is shown to be caused by two species, namely A. proteae comb. nov. on Protea spp. (South Africa), and A. leucospermi sp. nov. on Leucospermum spp. (Indonesia, Portugal, South Africa). Novel genera and species elucidated in this study include Gordonomyces mucovaginatus and Pseudopassalora gouriqua (hyphomycetes), and Xenoconiothyrium catenata (coelomycete), all on Protea spp. (South Africa). PMID:22403475

Crous, P W; Summerell, B A; Swart, L; Denman, S; Taylor, J E; Bezuidenhout, C M; Palm, M E; Marincowitz, S; Groenewald, J Z

2011-12-01

402

MODELING HOST-PATHOGEN INTERACTIONS: COMPUTATIONAL BIOLOGY AND BIOINFORMATICS FOR INFECTIOUS DISEASE RESEARCH (Session introduction)  

SciTech Connect

Pathogenic infections are a major cause of both human disease and loss of crop yields and animal stocks and thus cause immense damage to the worldwide economy. The significance of infectious diseases is expected to increase in an ever more connected warming world, in which new viral, bacterial and fungal pathogens can find novel hosts and ecologic niches. At the same time, the complex and sophisticated mechanisms by which diverse pathogenic agents evade defense mechanisms and subvert their hosts networks to suit their lifestyle needs is still very incompletely understood especially from a systems perspective [1]. Thus, understanding host-pathogen interactions is both an important and a scientifically fascinating topic. Recently, technology has offered the opportunity to investigate host-pathogen interactions on a level of detail and scope that offers immense computational and analytical possibilities. Genome sequencing was pioneered on some of these pathogens, and the number of strains and variants of pathogens sequenced to date vastly outnumbers the number of host genomes available. At the same time, for both plant and human hosts more and more data on population level genomic variation becomes available and offers a rich field for analysis into the genetic interactions between host and pathogen.

McDermott, Jason E.; Braun, Pascal; Bonneau, Richard A.; Hyduke, Daniel R.

2011-12-01

403

Comparison of fecal indicators with pathogenic bacteria and rotavirus in groundwater.  

PubMed

Groundwater is routinely analyzed for fecal indicators but direct comparisons of fecal indicators to the presence of bacterial and viral pathogens are rare. This study was conducted in rural Bangladesh where the human population density is high, sanitation is poor, and groundwater pumped from shallow tubewells is often contaminated with fecal bacteria. Five indicator microorganisms (E. coli, total coliform, F+RNA coliphage, Bacteroides and human-associated Bacteroides) and various environmental parameters were compared to the direct detection of waterborne pathogens by quantitative PCR in groundwater pumped from 50 tubewells. Rotavirus was detected in groundwater filtrate from the largest proportion of tubewells (40%), followed by Shigella (10%), Vibrio (10%), and pathogenic E. coli (8%). Spearman rank correlations and sensitivity-specificity calculations indicate that some, but not all, combinations of indicators and environmental parameters can predict the presence of pathogens. Culture-dependent fecal indicator bacteria measured on a single date did not predict total bacterial pathogens, but annually averaged monthly measurements of culturable E. coli did improve prediction for total bacterial pathogens. A qPCR-based E. coli assay was the best indicator for the bacterial pathogens. F+RNA coliphage were neither correlated nor sufficiently sensitive towards rotavirus, but were predictive of bacterial pathogens. Since groundwater cannot be excluded as a significant source of diarrheal disease in Bangladesh and neighboring countries with similar characteristics, the need to develop more effective methods for screening tubewells with respect to microbial contamination is necessary. PMID:22705866

Ferguson, Andrew S; Layton, Alice C; Mailloux, Brian J; Culligan, Patricia J; Williams, Daniel E; Smartt, Abby E; Sayler, Gary S; Feighery, John; McKay, Larry D; Knappett, Peter S K; Alexandrova, Ekaterina; Arbit, Talia; Emch, Michael; Escamilla, Veronica; Ahmed, Kazi Matin; Alam, Md Jahangir; Streatfield, P Kim; Yunus, Mohammad; van Geen, Alexander

2012-08-01

404