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1

Plant genomes enclose footprints of past infections by giant virus relatives  

PubMed Central

Nucleocytoplasmic large DNA viruses (NCLDVs) are eukaryotic viruses with large genomes (100?kb–2.5?Mb), which include giant Mimivirus, Megavirus and Pandoravirus. NCLDVs are known to infect animals, protists and phytoplankton but were never described as pathogens of land plants. Here, we show that the bryophyte Physcomitrella patens and the lycophyte Selaginella moellendorffii have open reading frames (ORFs) with high phylogenetic affinities to NCLDV homologues. The P. patens genes are clustered in DNA stretches (up to 13?kb) containing up to 16 NCLDV-like ORFs. Molecular evolution analysis suggests that the NCLDV-like regions were acquired by horizontal gene transfer from distinct but closely related viruses that possibly define a new family of NCLDVs. Transcriptomics and DNA methylation data indicate that the NCLDV-like regions are transcriptionally inactive and are highly cytosine methylated through a mechanism not relying on small RNAs. Altogether, our data show that members of NCLDV have infected land plants.

Maumus, Florian; Epert, Aline; Nogue, Fabien; Blanc, Guillaume

2014-01-01

2

Plant genomes enclose footprints of past infections by giant virus relatives.  

PubMed

Nucleocytoplasmic large DNA viruses (NCLDVs) are eukaryotic viruses with large genomes (100?kb-2.5?Mb), which include giant Mimivirus, Megavirus and Pandoravirus. NCLDVs are known to infect animals, protists and phytoplankton but were never described as pathogens of land plants. Here, we show that the bryophyte Physcomitrella patens and the lycophyte Selaginella moellendorffii have open reading frames (ORFs) with high phylogenetic affinities to NCLDV homologues. The P. patens genes are clustered in DNA stretches (up to 13?kb) containing up to 16 NCLDV-like ORFs. Molecular evolution analysis suggests that the NCLDV-like regions were acquired by horizontal gene transfer from distinct but closely related viruses that possibly define a new family of NCLDVs. Transcriptomics and DNA methylation data indicate that the NCLDV-like regions are transcriptionally inactive and are highly cytosine methylated through a mechanism not relying on small RNAs. Altogether, our data show that members of NCLDV have infected land plants. PMID:24969138

Maumus, Florian; Epert, Aline; Nogué, Fabien; Blanc, Guillaume

2014-01-01

3

Proteorhodopsin genes in giant viruses.  

PubMed

Viruses with large genomes encode numerous proteins that do not directly participate in virus biogenesis but rather modify key functional systems of infected cells. We report that a distinct group of giant viruses infecting unicellular eukaryotes that includes Organic Lake Phycodnaviruses and Phaeocystis globosa virus encode predicted proteorhodopsins that have not been previously detected in viruses. Search of metagenomic sequence data shows that putative viral proteorhodopsins are extremely abundant in marine environments. Phylogenetic analysis suggests that giant viruses acquired proteorhodopsins via horizontal gene transfer from proteorhodopsin-encoding protists although the actual donor(s) could not be presently identified. The pattern of conservation of the predicted functionally important amino acid residues suggests that viral proteorhodopsin homologs function as sensory rhodopsins. We hypothesize that viral rhodopsins modulate light-dependent signaling, in particular phototaxis, in infected protists. PMID:23036091

Yutin, Natalya; Koonin, Eugene V

2012-01-01

4

Failure of multinucleated giant cell formation in k562 cells infected with newcastle disease virus and human parainfluenza type 2 virus.  

PubMed

When K562 cells were infected with Newcastle disease virus (NDV) or human parainfluenza type 2 virus (hPIV-2), polykaryocyte formation could not be detected. Failure of multinucleated giant cell formation in K562 cells infected with either NDV or hPIV-2 is due to disturbance of the viral envelope-cell fusion step or to defect in the cell-cell fusion step, respectively. Especially, NDV completely replicated in K562 cells, and the hemagglutinin-neuraminidase and fusion proteins expressed on the cell surface of NDV-infected K562 cell were fully functional for fusion inducing activity. Therefore, the cell membranes of K562 cells are considered to be resistant to virus-induced cell fusion. Membrane fusion is regulated by many host factors including membrane fluidity, cytoskeletal systems, and fusion regulatory proteins system. An unknown regulatory mechanism of virus-induced cell fusion may function on the cell surface of K562 cells. PMID:17579271

Yamakawa, Izumi; Tsurudome, Masato; Kawano, Mitsuo; Nishio, Machiko; Komada, Hiroshi; Ito, Morihiro; Uji, Yukitaka; Ito, Yasuhiko

2007-01-01

5

Giant molluscum contagiosum - a clue to the diagnosis of human immunodeficiency virus infection.  

PubMed

Molluscum contagiosum (MC) is a benign cutaneous viral infection, affecting mainly children and young adults. Though the disease is self-limiting in immunocompetent individuals, a severe and prolonged course is associated with Human Immunodeficiency Virus (HIV) infection. The following reports an apparently healthy 2-year-old boy with extensive MC without any systemic illness. His parents died of tuberculosis. Investigations revealed him to be a case of HIV infection with severe immunosuppression. The fact that awareness of this condition as being the first sign of HIV infection should prompt diagnostic investigation, especially in India where access to healthcare facilities is limited. PMID:24206800

Basu, Sriparna; Kumar, Ashok

2013-12-01

6

Evolutionary dynamics of giant viruses and their virophages  

PubMed Central

Giant viruses contain large genomes, encode many proteins atypical for viruses, replicate in large viral factories, and tend to infect protists. The giant virus replication factories can in turn be infected by so called virophages, which are smaller viruses that negatively impact giant virus replication. An example is Mimiviruses that infect the protist Acanthamoeba and that are themselves infected by the virophage Sputnik. This study examines the evolutionary dynamics of this system, using mathematical models. While the models suggest that the virophage population will evolve to increasing degrees of giant virus inhibition, it further suggests that this renders the virophage population prone to extinction due to dynamic instabilities over wide parameter ranges. Implications and conditions required to avoid extinction are discussed. Another interesting result is that virophage presence can fundamentally alter the evolutionary course of the giant virus. While the giant virus is predicted to evolve toward increasing its basic reproductive ratio in the absence of the virophage, the opposite is true in its presence. Therefore, virophages can not only benefit the host population directly by inhibiting the giant viruses but also indirectly by causing giant viruses to evolve toward weaker phenotypes. Experimental tests for this model are suggested.

Wodarz, Dominik

2013-01-01

7

Hypoxia induces permeability and giant cell responses of Andes virus-infected pulmonary endothelial cells by activating the mTOR-S6K signaling pathway.  

PubMed

Andes virus (ANDV) is a South American hantavirus that causes a highly lethal hantavirus pulmonary syndrome (HPS) characterized by hypoxia, thrombocytopenia, and vascular leakage leading to acute pulmonary edema. ANDV infects human pulmonary microvascular and lymphatic endothelial cells (MECs and LECs, respectively) and nonlytically enhances the permeability of interendothelial cell adherence junctions in response to vascular endothelial growth factor (VEGF). Recent findings also indicate that ANDV causes the formation of giant endothelial cells. Here, we demonstrate that hypoxic conditions alone enhance permeability and giant cell responses of ANDV-infected MECs and LECs through activation of the mTOR signaling pathway. In contrast to infection of cells with nonpathogenic Tula virus (TULV), we observed that exposure of ANDV-infected MECs and LECs to hypoxic conditions resulted in a 3- to 6-fold increase in monolayer permeability and the formation of giant cells 3× to 5× normal size. ANDV infection in combination with hypoxic conditions resulted in the enhancement of hypoxia-inducible factor 1? (HIF1?)-directed VEGF A, angiopoietin 4, and EGLN3 transcriptional responses. Constitutive mTOR signaling induces the formation of giant cells via phosphorylation of S6K, and mTOR regulates hypoxia and VEGF A-induced cellular responses. We found that S6K was hyperphosphorylated in ANDV-infected, hypoxia-treated MECs and LECs and that rapamycin treatment for 1 h inhibited mTOR signaling responses and blocked permeability and giant cell formation in ANDV-infected monolayers. These findings indicate that ANDV infection and hypoxic conditions enhance mTOR signaling responses, resulting in enhanced endothelial cell permeability and suggest a role for rapamycin in therapeutically stabilizing the endothelium of microvascular and lymphatic vessels during ANDV infection. PMID:24067973

Gavrilovskaya, Irina N; Gorbunova, Elena E; Mackow, Erich R

2013-12-01

8

Giant viruses of amoebae as potential human pathogens.  

PubMed

Giant viruses infecting phagocytic protists are composed of mimiviruses, the record holders of particle and genome size amongst viruses, and marseilleviruses. Since the discovery in 2003 at our laboratory of the first of these giant viruses, the Mimivirus, a growing body of data has revealed that they are common inhabitants of our biosphere. Moreover, from the outset, the story of Mimivirus has been linked to that of patients exhibiting pneumonia and it was shown that patients developed antibodies to this amoebal pathogen. Since then, there have been several proven cases of human infection or colonization with giant viruses of amoebae, which are known to host several bacteria that are human pathogens. Mimiviruses and marseilleviruses represent a major challenge in human pathology, as virological procedures implemented to date have not used appropriate media to allow their culture, and molecular techniques have used filtration steps that likely prevented their detection. Nevertheless, there is an increasing body of evidence that mimiviruses might cause pneumonia and that humans carry marseilleviruses, and re-analyses of metagenomic databases have provided evidence that these giant viruses can be common in human samples. The proportion of human infections related to these giant mimiviruses and marseilleviruses and the precise short- and long-term consequences of these infections have been scarcely investigated so far and should be the subject of future works. PMID:24157884

Colson, Philippe; La Scola, Bernard; Raoult, Didier

2013-01-01

9

The origins of giant viruses, virophages and their relatives in host genomes  

PubMed Central

Giant viruses have revealed a number of surprises that challenge conventions on what constitutes a virus. The Samba virus newly isolated in Brazil expands the known distribution of giant mimiviruses to a near-global scale. These viruses, together with the transposon-related virophages that infect them, pose a number of questions about their evolutionary origins that need to be considered in the light of the complex entanglement between host, virus and virophage genomes. See research article: http://www.virologyj.com/content/11/1/95.

2014-01-01

10

Avian Influenza A Virus Infections in Humans  

MedlinePLUS

... Google Bookmarks Avian Influenza A Virus Infections in Humans On this Page Avian Influenza A Virus Infections ... A Viruses Avian Influenza A Virus Infections in Humans Although avian influenza A viruses usually do not ...

11

Yellow Fever Virus Infection  

PubMed Central

A sequential and quantitative survey of brain and liver of suckling mice for infective virus and complement-fixing antigen, after infection with yellow fever virus, showed that while there was progressive increase of infective virus content in both organs, only the brain showed a corresponding rise in CF antigen. Histopathological examination revealed that the liver was not significantly involved. The target organ was the brain, where the progressive pathological changes culminated in an acute encephalitis by the 3rd day of experiment. Organ destruction began with the molecular layer of the grey matter. But by the 4th day after infection the entire cerebral cortex was involved. At the initial stages the hippocampus was particularly affected. Tissue damage did not appear to be entirely due to the differential quantitative localization of infective virus. It was hypothesized that the CF antigen acting singly or in conjunction with some hypothetical proteins may be principally involved in the pathological outcome of the disease. ImagesFigs. 7-9Figs. 3-6

David-West, Tam. S.; Smith, J. A.

1971-01-01

12

Hepatitis E virus infection.  

PubMed

Hepatitis E virus (HEV) infection is a worldwide disease. An improved understanding of the natural history of HEV infection has been achieved within the last decade. Several reservoirs and transmission modes have been identified. Hepatitis E is an underdiagnosed disease, in part due to the use of serological assays with low sensitivity. However, diagnostic tools, including nucleic acid-based tests, have been improved. The epidemiology and clinical features of hepatitis E differ between developing and developed countries. HEV infection is usually an acute self-limiting disease, but in developed countries it causes chronic infection with rapidly progressive cirrhosis in organ transplant recipients, patients with hematological malignancy requiring chemotherapy, and individuals with HIV. HEV also causes extrahepatic manifestations, including a number of neurological syndromes and renal injury. Acute infection usually requires no treatment, but chronic infection should be treated by reducing immunosuppression in transplant patients and/or the use of antiviral therapy. In this comprehensive review, we summarize the current knowledge about the virus itself, as well as the epidemiology, diagnostics, natural history, and management of HEV infection in developing and developed countries. PMID:24396139

Kamar, Nassim; Dalton, Harry R; Abravanel, Florence; Izopet, Jacques

2014-01-01

13

SEROLOGIC RESPONSE TO A CANARYPOX-VECTORED CANINE DISTEMPER VIRUS VACCINE IN THE GIANT PANDA (AILUROPODA MELANOLEUCA)  

Microsoft Academic Search

The giant panda {Ailuropoda melanoleuca) is known to be susceptible to natural infection with canine distemper virus (CDV). Vaccination of giant pandas with conventional modified live CDV vaccines has been avoided due to the numerous carnivore species known to have become infected with CDV after vaccination. Serum-neutralizing antibodies to CDV were measured after s.c. and i.m. annual vaccination with a

Ellen Bronson; Sharon L. Deem; Carlos Sanchez; Suzan Murray

2007-01-01

14

Membrane Assembly during the Infection Cycle of the Giant Mimivirus  

PubMed Central

Although extensively studied, the structure, cellular origin and assembly mechanism of internal membranes during viral infection remain unclear. By combining diverse imaging techniques, including the novel Scanning-Transmission Electron Microscopy tomography, we elucidate the structural stages of membrane biogenesis during the assembly of the giant DNA virus Mimivirus. We show that this elaborate multistage process occurs at a well-defined zone localized at the periphery of large viral factories that are generated in the host cytoplasm. Membrane biogenesis is initiated by fusion of multiple vesicles, ?70 nm in diameter, that apparently derive from the host ER network and enable continuous supply of lipid components to the membrane-assembly zone. The resulting multivesicular bodies subsequently rupture to form large open single-layered membrane sheets from which viral membranes are generated. Membrane generation is accompanied by the assembly of icosahedral viral capsids in a process involving the hypothetical major capsid protein L425 that acts as a scaffolding protein. The assembly model proposed here reveals how multiple Mimivirus progeny can be continuously and efficiently generated and underscores the similarity between the infection cycles of Mimivirus and Vaccinia virus. Moreover, the membrane biogenesis process indicated by our findings provides new insights into the pathways that might mediate assembly of internal viral membranes in general.

Mutsafi, Yael; Shimoni, Eyal; Shimon, Amir; Minsky, Abraham

2013-01-01

15

Virus infection and knee injury.  

PubMed Central

Serological evidence of virus infection was sought in 31 consecutive patients presenting with knee swelling and compared with age/sex-matched controls. In a normal age/sex-matched control group, 42% of patients had evidence of recent or past infection with Coxsackie B virus, emphasising the care required in the evaluation of the significance of Coxsackie B neutralization titres in individual patients. Of 12 patients presenting with knee swelling and a history of a twisting injury, eight had serological evidence of recent or past infection with Coxsackie B virus, and one had evidence of a current adenovirus infection.

Driscoll, P; Venner, R; Clements, G B

1987-01-01

16

Samba virus: a novel mimivirus from a giant rain forest, the Brazilian Amazon  

PubMed Central

Background The identification of novel giant viruses from the nucleocytoplasmic large DNA viruses group and their virophages has increased in the last decade and has helped to shed light on viral evolution. This study describe the discovery, isolation and characterization of Samba virus (SMBV), a novel giant virus belonging to the Mimivirus genus, which was isolated from the Negro River in the Brazilian Amazon. We also report the isolation of an SMBV-associated virophage named Rio Negro (RNV), which is the first Mimivirus virophage to be isolated in the Americas. Methods/results Based on a phylogenetic analysis, SMBV belongs to group A of the putative Megavirales order, possibly a new virus related to Acanthamoeba polyphaga mimivirus (APMV). SMBV is the largest virus isolated in Brazil, with an average particle diameter about 574 nm. The SMBV genome contains 938 ORFs, of which nine are ORFans. The 1,213.6 kb SMBV genome is one of the largest genome of any group A Mimivirus described to date. Electron microscopy showed RNV particle accumulation near SMBV and APMV factories resulting in the production of defective SMBV and APMV particles and decreasing the infectivity of these two viruses by several logs. Conclusion This discovery expands our knowledge of Mimiviridae evolution and ecology.

2014-01-01

17

Thirty-thousand-year-old distant relative of giant icosahedral DNA viruses with a pandoravirus morphology.  

PubMed

The largest known DNA viruses infect Acanthamoeba and belong to two markedly different families. The Megaviridae exhibit pseudo-icosahedral virions up to 0.7 ?m in diameter and adenine-thymine (AT)-rich genomes of up to 1.25 Mb encoding a thousand proteins. Like their Mimivirus prototype discovered 10 y ago, they entirely replicate within cytoplasmic virion factories. In contrast, the recently discovered Pandoraviruses exhibit larger amphora-shaped virions 1 ?m in length and guanine-cytosine-rich genomes up to 2.8 Mb long encoding up to 2,500 proteins. Their replication involves the host nucleus. Whereas the Megaviridae share some general features with the previously described icosahedral large DNA viruses, the Pandoraviruses appear unrelated to them. Here we report the discovery of a third type of giant virus combining an even larger pandoravirus-like particle 1.5 ?m in length with a surprisingly smaller 600 kb AT-rich genome, a gene content more similar to Iridoviruses and Marseillevirus, and a fully cytoplasmic replication reminiscent of the Megaviridae. This suggests that pandoravirus-like particles may be associated with a variety of virus families more diverse than previously envisioned. This giant virus, named Pithovirus sibericum, was isolated from a >30,000-y-old radiocarbon-dated sample when we initiated a survey of the virome of Siberian permafrost. The revival of such an ancestral amoeba-infecting virus used as a safe indicator of the possible presence of pathogenic DNA viruses, suggests that the thawing of permafrost either from global warming or industrial exploitation of circumpolar regions might not be exempt from future threats to human or animal health. PMID:24591590

Legendre, Matthieu; Bartoli, Julia; Shmakova, Lyubov; Jeudy, Sandra; Labadie, Karine; Adrait, Annie; Lescot, Magali; Poirot, Olivier; Bertaux, Lionel; Bruley, Christophe; Couté, Yohann; Rivkina, Elizaveta; Abergel, Chantal; Claverie, Jean-Michel

2014-03-18

18

Probiotics in respiratory virus infections.  

PubMed

Viral respiratory infections are the most common diseases in humans. A large range of etiologic agents challenge the development of efficient therapies. Research suggests that probiotics are able to decrease the risk or duration of respiratory infection symptoms. However, the antiviral mechanisms of probiotics are unclear. The purpose of this paper is to review the current knowledge on the effects of probiotics on respiratory virus infections and to provide insights on the possible antiviral mechanisms of probiotics. A PubMed and Scopus database search was performed up to January 2014 using appropriate search terms on probiotic and respiratory virus infections in cell models, in animal models, and in humans, and reviewed for their relevance. Altogether, thirty-three clinical trials were reviewed. The studies varied highly in study design, outcome measures, probiotics, dose, and matrices used. Twenty-eight trials reported that probiotics had beneficial effects in the outcome of respiratory tract infections (RTIs) and five showed no clear benefit. Only eight studies reported investigating viral etiology from the respiratory tract, and one of these reported a significant decrease in viral load. Based on experimental studies, probiotics may exert antiviral effects directly in probiotic-virus interaction or via stimulation of the immune system. Although probiotics seem to be beneficial in respiratory illnesses, the role of probiotics on specific viruses has not been investigated sufficiently. Due to the lack of confirmatory studies and varied data available, more randomized, double-blind, and placebo-controlled trials in different age populations investigating probiotic dose response, comparing probiotic strains/genera, and elucidating the antiviral effect mechanisms are necessary. PMID:24638909

Lehtoranta, L; Pitkäranta, A; Korpela, R

2014-08-01

19

Giant virus in the sea: Extending the realm of Megaviridae to Viridiplantae.  

PubMed

The viral nature of the first "giant virus," Mimivirus, was realized in 2003, 10 y after its initial isolation from the water of a cooling tower in Bradford, UK. Soon after its genome was sequenced, the mining of the Global Ocean Sampling environmental sequence database revealed that the closest relatives of Mimivirus, only known to infect Acanthamoeba, were to be found in the sea. These predicted marine Mimivirus relatives remained elusive until 2010, with the first genomic characterization of a virus infecting a heterotrophic unicellular eukaryote, the microflagellate grazer Cafeteria roenbergensis. The genome analysis of a virus (PgV) infecting the common unicellular algae Phaeocystis globosa now shows that it is a bona fide member of the Mimivirus family (i.e., the Megaviridae), extending the realm of these giant viruses to abundant blooming phytoplankton species. Despite its smaller genome size (460 kb encoding 434 proteins), PgV exhibits the most intriguing feature of the previously characterized Megaviridae: an associated virophage. However, the 19-kb virophage genome, devoid of a capsid gene, is packaged in the PgV particle and propagated as a "viral plasmid," the first ever described. The PgV genome also exhibits the duplication of "core genes," normally present as single copies and a putative new type of mobile element. In a DNA polymerase phylogeny including representatives of the three cellular domains, PgV and the other Megaviridae cluster into their own clade deeply branching between domains Archaea and Eukarya domains, thus exhibiting the topology of a fourth domain in the Tree of Life. PMID:24563700

Claverie, Jean-Michel

2013-11-01

20

Serological survey on canine coronavirus antibodies in giant pandas by virus neutralization test  

Microsoft Academic Search

In order to survey the infectious situation of canine coronavirus (CCV) in giant panda population, a virus neutralization\\u000a test detecting specific antibodies against CCV in giant panda’s sera was established by using two-fold dilutions of serum\\u000a and 100 TCID50 of the virus. The 62 sera samples of giant pandas, which were gathered from zoos and reserve region of Sichuan Province,

Qiao Jun; Xia Xian-zhu; Yang Song-tao; Li De-sheng; Hu Gui-xue; Gao Yu-wei; Sun He-ting; Zhao Zhong-pen; Xie Zhi-jing; Yan Fang; He Wen-qi; Huang Gen

2004-01-01

21

Human Immunodeficiency Virus (HIV) Primary Infection  

MedlinePLUS

newsletter | contact Share | Human Immunodeficiency Virus (HIV) Primary Infection Information for adults A A A When HIV is first contracted, there may be ... 1–6 weeks following exposure to HIV (the human immunodeficiency virus). Chronic infection with this virus can ...

22

Morphology and infectivity of virus that persistently caused infection in an AGS cell line.  

PubMed

A recent report has indicated that proteins and genes of simian virus 5 (SV5) are detected in a human gastric adenocarcinoma (AGS) cell line, which is widely provided for oncology, immunology, and microbiology research. However, the production of infective virions has not been determined in this cell line. In this study, the morphology and infectivity of the virus particles of the AGS cell line were studied by light and electron microscopy and virus transmission assay. The virus particles were approximately 176.0 ± 41.1 nm in diameter. The particles possessed projections 8-12 nm long on the surface and contained a nucleocapsid determined to be 13-18 nm in width and less than 1,000 nm in length. The virus was transmissible to the Vero cell line, induced multinuclear giant cell formation, and reproduced the same shape of antigenic virions. In this study, the persistently infected virus in the AGS cell line was determined to be infective and form reproducible virions, and a new morphological feature of SV5 was determined. PMID:22179184

Ooi, Yukimasa; Daikoku, Eriko; Wu, Hong; Aoki, Hiroaki; Morita, Chizuko; Nakano, Takashi; Kohno, Takehiro; Takasaki, Tomohiko; Sano, Kouichi

2011-12-01

23

Susceptibility of laboratory and domestic animals to experimental infection with Potiskum virus.  

PubMed

The biological characteristics of Potiskum virus, a hitherto undescribed virus isolated in Nigeria from the liver of a giant rat (Cricetomys gambianus), were studied by experimental infections of laboratory and domestic animals. The laboratory animal hosts used included mice, rats, rabbits and chicks. Suckling and weaning mice succumbed to fatal infection when infected with Potiskum virus by intracerebral or intraperitoneal routes. Infected mice had high titres of virus and mild histopathological lesions which were confined to the brain. Chicks also developed a fatal disease following subcutaneous or oral infections with Potiskum virus. In contrast, albino rats and rabbits failed to succumb to overt disease by subcutaneous and intraperitoneal routes of inoculation. Albino rats did not develop antibody but rabbits developed haemagglutination inhibiting, neutralising and complement fixing antibodies. PMID:2558278

Omilabu, S A; Fagbami, A H; Olaleye, O D

1989-01-01

24

Multifocal VZV vasculopathy with temporal artery infection mimics giant cell arteritis  

PubMed Central

Objective: To address the incidence of varicella-zoster virus (VZV) infection in patients with biopsy-negative giant cell arteritis (GCA), we examined archived biopsy-negative temporal arteries from subjects with clinically suspected GCA for the presence of VZV antigen. Methods: Formalin-fixed, paraffin-embedded temporal arteries that were pathologically negative for GCA and normal temporal arteries were analyzed immunohistochemically for VZV and herpes simplex virus-1 (HSV-1) antigen. Results: Five (21%) of 24 temporal arteries from patients who were clinically suspect but biopsy negative for GCA revealed VZV but not HSV-1 by immunohistochemical analysis. Thirteen normal temporal arteries did not contain VZV or HSV-1 antigen. All 5 subjects whose temporal arteries contained VZV antigen presented with clinical and laboratory features of GCA and early visual disturbances. Conclusion: Multifocal VZV vasculopathy can present with the full spectrum of clinical features and laboratory abnormalities characteristically seen in GCA.

Nagel, Maria A.; Bennett, Jeffrey L.; Khmeleva, Nelly; Choe, Alexander; Rempel, April; Boyer, Philip J.

2013-01-01

25

Virus Infections in the Nervous System  

PubMed Central

Virus infections usually begin in peripheral tissues and can invade the mammalian nervous system (NS), spreading into the peripheral (PNS) and more rarely the central nervous systems (CNS). The CNS is protected from most virus infections by effective immune responses and multi-layer barriers. However, some viruses enter the NS with high efficiency via the bloodstream or by directly infecting nerves that innervate peripheral tissues, resulting in debilitating direct and immune-mediated pathology. Most viruses in the NS are opportunistic or accidental pathogens, but a few, most notably the alpha herpesviruses and rabies virus, have evolved to enter the NS efficiently and exploit neuronal cell biology. Remarkably, the alpha herpesviruses can establish quiescent infections in the PNS, with rare but often fatal CNS pathology. Here we review how viruses gain access to and spread in the well-protected CNS, with particular emphasis on alpha herpesviruses, which establish and maintain persistent NS infections.

Koyuncu, Orkide O.; Hogue, Ian B.; Enquist, Lynn W.

2013-01-01

26

CELLULAR PATHOLOGY OF A GRANULOSIS VIRUS INFECTION  

EPA Science Inventory

Nuclear and cytoplasmic ultrastructural changes were examined in Spodoptera frugiperda (SF) larval fat body cells infected with granulosis virus (GV). Soon after infection necleocapsidlike structures were observed within the nucleus associated with nuclear pores. The earliest cel...

27

Immunology of hepatitis B virus and hepatitis C virus infection  

Microsoft Academic Search

More than 500 million people worldwide are persistently infected with the hepatitis B virus (HBV) and\\/or hepatitis C virus (HCV) and are at risk of developing chronic liver disease, cirrhosis and hepatocellular carcinoma. Despite many common features in the pathogenesis of HBV- and HCV-related liver disease, these viruses markedly differ in their virological properties and in their immune escape and

Michelina Nascimbeni; Barbara Rehermann

2005-01-01

28

The greasy response to virus infections  

PubMed Central

Previews Virus replication requires lipid metabolism, but how lipids mediate virus infection remains obscure. In this issue, Amini-Bavil-Olyaee et al. (2013) reveal that IFITM proteins disturb cholesterol homeostasis to block virus entry. Previously in Cell, Morita and colleagues (2013) showed the antiviral potency of the lipid mediator protectin D1.

Tanner, Lukas Bahati; Lee, Benhur

2013-01-01

29

DNA-Dependent RNA Polymerase Detects Hidden Giant Viruses in Published Databanks.  

PubMed

Environmental metagenomic studies show that there is a "dark matter," composed of sequences not linked to any known organism, as determined mainly using ribosomal DNA (rDNA) sequences, which therefore ignore giant viruses. DNA-dependent RNA polymerase (RNAP) genes are universal in microbes and conserved in giant viruses and may replace rDNA for identifying microbes. We found while reconstructing RNAP subunit 2 (RNAP2) phylogeny that a giant virus sequenced together with the genome of a large eukaryote, Hydra magnipapillata, has been overlooked. To explore the dark matter, we used viral RNAP2 and reconstructed putative ancestral RNAP2, which were significantly superior in detecting distant clades than current sequences, and we revealed two additional unknown mimiviruses, misclassified as an euryarchaeote and an oomycete plant pathogen, and detected unknown putative viral clades. We suggest using RNAP systematically to decipher the black matter and identify giant viruses. PMID:24929085

Sharma, Vikas; Colson, Philippe; Giorgi, Roch; Pontarotti, Pierre; Raoult, Didier

2014-01-01

30

Respiratory Marburg virus infection in guinea pigs.  

PubMed

Marburg virus (MV) reproduction in organs, hematological and pathological changes were studied by virological and clinical methods, light and electron microscopy in guinea pigs respiratory challenged by the virus. Liver and spleen were most affected by MV, as in parenteral infection. The sequential involvement of cells in virus replication was also the same as in parenteral infection, with monocytoid-macrophagal cells infected first, followed by hepatocytes, spongiocytes, endotheliocytes and fibroblasts. Hemopoietic cells showed evidence of severe damage in respiratory infected guinea pigs. A distinguishing feature of the respiratory infection was close contact of leucocytes with MV infected cells. It is suggested that the entrapment and accumulation of MV in the lungs of respiratory infected guinea pigs makes possible the enfoldment leucocyte attack which does not, however, result in destruction of the infected cells. PMID:8973532

Ryabchikova, E; Strelets, L; Kolesnikova, L; Pyankov, O; Sergeev, A

1996-01-01

31

Virus-Induced Aggregates in Infected Cells  

PubMed Central

During infection, many viruses induce cellular remodeling, resulting in the formation of insoluble aggregates/inclusions, usually containing viral structural proteins. Identification of aggregates has become a useful diagnostic tool for certain viral infections. There is wide variety of viral aggregates, which differ by their location, size, content and putative function. The role of aggregation in the context of a specific virus is often poorly understood, especially in the case of plant viruses. The aggregates are utilized by viruses to house a large complex of proteins of both viral and host origin to promote virus replication, translation, intra- and intercellular transportation. Aggregated structures may protect viral functional complexes from the cellular degradation machinery. Alternatively, the activation of host defense mechanisms may involve sequestration of virus components in aggregates, followed by their neutralization as toxic for the host cell. The diversity of virus-induced aggregates in mammalian and plant cells is the subject of this review.

Moshe, Adi; Gorovits, Rena

2012-01-01

32

LCM virus infection of cells in vitro*  

PubMed Central

Most mammalian cells cultivated in vitro can be infected with lymphocytic choriomeningitis (LCM) virus. In addition to infectious virus, the cells produce antigenic material that fixes complement in the presence of antibody and is precipitated by antiserum. Intracellular antigen can also be demonstrated by the immunofluorescence procedure. When infected cells are viewed with the electron microscope, viral structures are seen either budding from or in association with the cell membranes. Immunoelectron microscopy, immunofluorescence, and cytotoxicity tests reveal virus-specific antigens on the surface of intact cells. Virus multiplication may be succeeded by cytolysis. Two LCM virus-specific antigens (or antigenic groups) can at present be distinguished. One corresponds to the infectious virus; the other is the complement-fixing “soluble” antigen. This extractable complement-fixing activity is produced by infected cells and is also a structural component of the infectious virus. It is not represented on the surface of either the virion or the infected cell. The cytolytic potential of LCM virus varies and is dependent on its previous passage history. Cytolytic and “attenuated” variants are able to initiate persistent infection of Mus musculus. Together with infectious virus, particles are produced that temporarily protect cells against standard virus. They appear to be by-products of virus multiplication, not in the sense of deletion mutants but of virus structures insufficiently equipped for their own active or passive replication, though capable of interfering with infectious virus. No evidence has been found for the generation of “defective interfering” particles, though their presence has not yet been excluded. ImagesFig. 3Fig. 4Fig. 5Fig. 6Fig. 7Fig. 8

Lehmann-Grube, F.; Popescu, M.; Schaefer, H.; Gschwender, H. H.

1975-01-01

33

Host cell autophagy promotes BK virus infection.  

PubMed

Autophagy is important for a variety for virus life cycles. We sought to determine the role of autophagy in human BK polyomavirus (BKPyV) infection. The addition excess amino acids during viral infection reduced BKPyV infection. Perturbing autophagy levels using inhibitors, 3-MA, bafilomycin A1, and spautin-1, also reduced infection, while rapamycin treatment of host cells increased infection. siRNA knockdown of autophagy genes, ATG7 and Beclin-1, corresponded to a decrease in BKPyV infection. BKPyV infection not only correlated with autophagosome formation, but also virus particles localized to autophagy-specific compartments early in infection. These data support a novel role for autophagy in the promotion of BKPyV infection. PMID:24889228

Bouley, Stephanie J; Maginnis, Melissa S; Derdowski, Aaron; Gee, Gretchen V; O'Hara, Bethany A; Nelson, Christian D; Bara, Anne M; Atwood, Walter J; Dugan, Aisling S

2014-05-01

34

Swine influenza virus infections in man.  

PubMed

Because pigs are susceptible to both avian and human influenza viruses, genetic reassortment between avian, human, and/or swine influenza viruses in the pig host can lead to the generation of novel influenza A viruses (Ma et al. 2009). Since the first serological evidence of a swine influenza virus (SIV) infecting humans in 1958, sporadic cases have continued to occur. In recent years, case reports have been increasing, seemingly in concert with modern pig farming and the emergence of triple reassortant SIVs in swine. SIV infections in man generally are mild or subclinical, and often are not diagnosed; however, SIV infections can be quite serious in patients with underlying medical conditions. As of August 2010, 73 case reports of symptomatic human SIV infections have been documented in the medical literature or reported by health officials (excluding cases of the 2009 pandemic H1N1 influenza virus), of which 7 infections (10 %) resulted in death. While exposure to swine is often considered a risk factor for human SIV infections, 37 of 73 (51 %) reported cases had no known exposure to pigs; consequently, SIV may be crossing the species barrier via transmission routes yet to be acknowledged. In addition, human-to-human transmission was suspected in 10 of 34 (30 %) of the cases with epidemiological investigation. This chapter discusses the observations of illness and infections in humans, risk factors associated with infection, and methods for diagnosing human infections of SIV. PMID:23023606

Krueger, Whitney S; Gray, Gregory C

2013-01-01

35

Dengue Virus Infection Perturbs Lipid Homeostasis in Infected Mosquito Cells  

PubMed Central

Dengue virus causes ?50–100 million infections per year and thus is considered one of the most aggressive arthropod-borne human pathogen worldwide. During its replication, dengue virus induces dramatic alterations in the intracellular membranes of infected cells. This phenomenon is observed both in human and vector-derived cells. Using high-resolution mass spectrometry of mosquito cells, we show that this membrane remodeling is directly linked to a unique lipid repertoire induced by dengue virus infection. Specifically, 15% of the metabolites detected were significantly different between DENV infected and uninfected cells while 85% of the metabolites detected were significantly different in isolated replication complex membranes. Furthermore, we demonstrate that intracellular lipid redistribution induced by the inhibition of fatty acid synthase, the rate-limiting enzyme in lipid biosynthesis, is sufficient for cell survival but is inhibitory to dengue virus replication. Lipids that have the capacity to destabilize and change the curvature of membranes as well as lipids that change the permeability of membranes are enriched in dengue virus infected cells. Several sphingolipids and other bioactive signaling molecules that are involved in controlling membrane fusion, fission, and trafficking as well as molecules that influence cytoskeletal reorganization are also up regulated during dengue infection. These observations shed light on the emerging role of lipids in shaping the membrane and protein environments during viral infections and suggest membrane-organizing principles that may influence virus-induced intracellular membrane architecture.

Perera, Rushika; Moore, Ronald J.; Weitz, Karl W.; Pasa-Tolic, Ljiljana; Metz, Thomas O.; Adamec, Jiri; Kuhn, Richard J.

2012-01-01

36

Innate immunity to influenza virus infection  

PubMed Central

Influenza viruses are a major pathogen of both humans and animals. Recent studies using gene-knockout mice have led to an in-depth understanding of the innate sensors that detect influenza virus infection in a variety of cell types. Signalling downstream of these sensors induces distinct sets of effector mechanisms that block virus replication and promote viral clearance by inducing innate and adaptive immune responses. In this Review, we discuss the various ways in which the innate immune system uses pattern recognition receptors to detect and respond to influenza virus infection. We consider whether the outcome of innate sensor stimulation promotes antiviral resistance or disease tolerance, and propose rational treatment strategies for the acute respiratory disease that is caused by influenza virus infection.

Iwasaki, Akiko; Pillai, Padmini S.

2014-01-01

37

Acanthamoeba polyphaga mimivirus and other giant viruses: an open field to outstanding discoveries  

PubMed Central

In 2003, Acanthamoeba polyphaga mimivirus (APMV) was first described and began to impact researchers around the world, due to its structural and genetic complexity. This virus founded the family Mimiviridae. In recent years, several new giant viruses have been isolated from different environments and specimens. Giant virus research is in its initial phase and information that may arise in the coming years may change current conceptions of life, diversity and evolution. Thus, this review aims to condense the studies conducted so far about the features and peculiarities of APMV, from its discovery to its clinical relevance.

2014-01-01

38

Dendritic cells during Epstein Barr virus infection  

PubMed Central

Epstein Barr virus (EBV) causes persistent infection in more than 90% of the human adult population and is associated with 2% of all tumors in humans. This ?-herpes virus infects primarily human B and epithelial cells, but it has been reported to be sensed by dendritic cells (DCs) during primary infection. These activated DCs are thought to contribute to innate restriction of EBV infection and initiate EBV-specific adaptive immune responses via cross-priming. The respective evidence and their potential importance for EBV-specific vaccine development will be discussed in this review.

Christian, Munz

2014-01-01

39

Nipah Virus Infection in Dogs, Malaysia, 1999  

PubMed Central

The 1999 outbreak of Nipah virus encephalitis in humans and pigs in Peninsular Malaysia ended with the evacuation of humans and culling of pigs in the epidemic area. Serologic screening showed that, in the absence of infected pigs, dogs were not a secondary reservoir for Nipah virus.

Alim, Asiah N.M.; Bunning, Michel L.; Lee, Ong Bee; Wagoner, Kent D.; Amman, Brian R.; Stockton, Patrick C.; Ksiazek, Thomas G.

2009-01-01

40

Human Immunodeficiency Virus Type 1 Infection of Neural Xenografts  

NASA Astrophysics Data System (ADS)

Human immunodeficiency virus type 1 (HIV-1) infection is highly specific for its human host. To study HIV-1 infection of the human nervous system, we have established a small animal model in which second-trimester (11 to 17.5 weeks) human fetal brain or neural retina is transplanted to the anterior chamber of the eye of immunosuppressed adult rats. The human xenografts vascularized, formed a blood-brain barrier, and differentiated, forming neurons and glia. The xenografts were infected with cell-free HIV-1 or with HIV-1-infected human monocytes. Analysis by polymerase chain reaction revealed HIV-1 sequences in DNA from xenograft tissue exposed to HIV-1 virions, and in situ hybridization demonstrated HIV-1 mRNA localized in macrophages and multinucleated giant cells. Pathological damage was observed only in neural xenografts containing HIV-1-infected human monocytes, supporting the hypothesis that these cells mediate neurotoxicity. This small animal model allows the study of direct and indirect effects of HIV-1 infection on developing human fetal neural tissues, and it should prove useful in evaluating antiviral therapies, which must ultimately target HIV-1 infection of the brain.

Cvetkovich, Therese A.; Lazar, Eliot; Blumberg, Benjamin M.; Saito, Yoshihiro; Eskin, Thomas A.; Reichman, Richard; Baram, David A.; del Cerro, Coca; Gendelman, Howard E.; del Cerro, Manuel; Epstein, Leon G.

1992-06-01

41

Pathogenesis of hepatitis B virus infection  

PubMed Central

Infection with hepatitis B virus (HBV) leads to a wide spectrum of clinical presentations ranging from an asymptomatic carrier state to self-limited acute or fulminant hepatitis to chronic hepatitis with progression to cirrhosis and hepatocellular carcinoma. Infection with HBV is one of the most common viral diseases affecting man. Both viral factors as well as the host immune response have been implicated in the pathogenesis and clinical outcome of HBV infection. In this review, we will discuss the impact of virus-host interactions for the pathogenesis of HBV infection and liver disease. These interactions include the relevance of naturally occurring viral variants for clinical disease, the role of virus-induced apoptosis for HBV-induced liver cell injury and the impact of antiviral immune responses for outcome of infection.

Baumert, Thomas F; Thimme, Robert; von Weizsacker, Fritz

2007-01-01

42

Robust hepatitis C virus infection in vitro.  

PubMed

The absence of a robust cell culture model of hepatitis C virus (HCV) infection has severely limited analysis of the HCV life cycle and the development of effective antivirals and vaccines. Here we report the establishment of a simple yet robust HCV cell culture infection system based on the HCV JFH-1 molecular clone and Huh-7-derived cell lines that allows the production of virus that can be efficiently propagated in tissue culture. This system provides a powerful tool for the analysis of host-virus interactions that should facilitate the discovery of antiviral drugs and vaccines for this important human pathogen. PMID:15939869

Zhong, Jin; Gastaminza, Pablo; Cheng, Guofeng; Kapadia, Sharookh; Kato, Takanobu; Burton, Dennis R; Wieland, Stefan F; Uprichard, Susan L; Wakita, Takaji; Chisari, Francis V

2005-06-28

43

Robust hepatitis C virus infection in vitro  

PubMed Central

The absence of a robust cell culture model of hepatitis C virus (HCV) infection has severely limited analysis of the HCV life cycle and the development of effective antivirals and vaccines. Here we report the establishment of a simple yet robust HCV cell culture infection system based on the HCV JFH-1 molecular clone and Huh-7-derived cell lines that allows the production of virus that can be efficiently propagated in tissue culture. This system provides a powerful tool for the analysis of host-virus interactions that should facilitate the discovery of antiviral drugs and vaccines for this important human pathogen.

Zhong, Jin; Gastaminza, Pablo; Cheng, Guofeng; Kapadia, Sharookh; Kato, Takanobu; Burton, Dennis R.; Wieland, Stefan F.; Uprichard, Susan L.; Wakita, Takaji; Chisari, Francis V.

2005-01-01

44

Viral dynamics in hepatitis B virus infection.  

PubMed Central

Treatment of chronic hepatitis B virus (HBV) infections with the reverse transcriptase inhibitor lamivudine leads to a rapid decline in plasma viremia and provides estimates for crucial kinetic constants of HBV replication. We find that in persistently infected patients, HBV particles are cleared from the plasma with a half-life of approximately 1.0 day, which implies a 50% daily turnover of the free virus population. Total viral release into the periphery is approximately 10(11) virus particles per day. Although we have no direct measurement of the infected cell mass, we can estimate the turnover rate of these cells in two ways: (i) by comparing the rate of viral production before and after therapy or (ii) from the decline of hepatitis B antigen during treatment. These two independent methods give equivalent results: we find a wide distribution of half-lives for virus-producing cells, ranging from 10 to 100 days in different patients, which may reflect differences in rates of lysis of infected cells by immune responses. Our analysis provides a quantitative understanding of HBV replication dynamics in vivo and has implications for the optimal timing of drug treatment and immunotherapy in chronic HBV infection. This study also represents a comparison for recent findings on the dynamics of human immunodeficiency virus (HIV) infection. The total daily production of plasma virus is, on average, higher in chronic HBV carriers than in HIV-infected patients, but the half-life of virus-producing cells is much shorter in HIV. Most strikingly, there is no indication of drug resistance in HBV-infected patients treated for up to 24 weeks.

Nowak, M A; Bonhoeffer, S; Hill, A M; Boehme, R; Thomas, H C; McDade, H

1996-01-01

45

Fate of Sendai Virus Ribonucleoprotein in Virus-infected Cells  

PubMed Central

The cytoplasmic extracts of Ehrlich ascites tumor cells infected with 32PO4 and 3H-leucine-labeled Sendai virus have been examined during the course of infection with respect to sedimentation behavior and buoyant densities of input virus radioactivity. It was found that 32P and 3H radioactivities were coincident, and, at 30 min after infection, the bulk of radioactivity was recovered in the polysome region of a sucrose gradient in the position of Sendai virus ribonucleoprotein (210S). The heterogeneity of radioactivity profiles appeared at 1 hr after infection and increased during 6 hr of incubation. The buoyant densities of input virus components were determined by banding in CsCl gradient. Here again the bulk of coincident 32P and 3H radioactivity at 30 min after infection banded at the same density as Sendai virus ribonucleoprotein (1.31 g/cm3.) This component disappeared at 3 hr after infection, and 32P and 3H radioactivities were now found in components banded at densities 1.38, 1.41, 1.45, 1.49, and 1.55 g/cm3. The results presented are consistent with the idea that virus ribonucleoprotein is retained in the cytoplasm of infected cells during at least 6 hr of incubation, being partly deproteinized in the course of infection. The nature of components which banded at ? = 1.41, 1.45, 1.49, and 1.55 as complexes of partly deproteinized ribonucleoprotein with ribosomes will be described in a separate paper.

Bukrinskaya, A. G.; Zhdanov, V. M.; Vorkunova, G. K.

1969-01-01

46

Hepatitis B Virus Infection: Epidemiology and Vaccination  

Microsoft Academic Search

Worldwide, two billion people have been infected with hepatitis B virus (HBV), 360 million have chronic infection, and 600,000 die each year from HBV-related liver disease or hepatocellular carcinoma. This comprehensive re- view of hepatitis B epidemiology and vaccines focuses on definitive and influential studies and highlights current trends, policies, and directions. HBV can be transmitted vertically, through sexual or

Colin W. Shepard; Edgar P. Simard; Lyn Finelli; Anthony E. Fiore; Beth P. Bell

2006-01-01

47

Toscana virus infection in Catalonia (Spain).  

PubMed

Toscana virus (TOSV), an arthropod-borne phlebovirus, is an important agent of acute meningitis and meningoencephalitis in the Mediterranean area. The epidemiology of the infection in humans in Catalonia is at present unknown. In this study, we found a seroprevalence of infection of 6%, and 2 clinical cases were detected by serology and/or PCR. PMID:23421893

Cardeñosa, Neus; Kaptoul, Diana; Fernández-Viladrich, Pedro; Aranda, Carles; de Ory, Fernando; Niubó, Jordi; Plans, Pere; Domínguez, Angela; Fedele, Giovanni; Tenorio, Antonio; Sánchez-Seco, María Paz

2013-04-01

48

Fibromyalgia-associated hepatitis C virus infection  

Microsoft Academic Search

SUMMARY The objective was to determine whether there might be an association between hepatitis C virus (HCV) chronic infection and fibromyalgia (FM). We determined the prevalence of HCV infection in 112 FM patients, in comparison with matched rheum- atoid arthritis (RA) patients from the out-patient clinic of a teaching tertiary care general hospital. Furthermore, we looked for evidence of FM

J. RIVERA; A. DE DIEGO; M. TRINCHET; A. GARCIA MONFORTE

1997-01-01

49

Controversies about occult hepatitis B virus infection  

PubMed Central

We read with great interest the paper written by Shi et al, reviewing the molecular characteristics and stages of chronic hepatitis B virus (HBV) infection. We think that some points in the definition of occult HBV infection (OBI) and their conclusion about the management of OBI may need further considerations.

Ozaslan, Ersan; Purnak, Tugrul

2009-01-01

50

HUMAN IMMUNODEFICIENCY VIRUS (HIV) DISEASE HUMAN IMMUNODEFICIENCY VIRUS AND HEPATITIS C VIRUS CO-INFECTION  

Microsoft Academic Search

Hepatitis C virus (HCV) infection is a major cause of liver disease and hepatocellular carci- noma worldwide, as well as the leading cause of liver transplantations in the United States. As a result of similar modes of transmission, approximately 30% of HIV-infected individuals are co-infected with HCV. Among intravenous drug users, almost 90% of people infected with HIVare also infected

Stacey R. VLAHAKIS

51

Inhibition of Enveloped Viruses Infectivity by Curcumin  

PubMed Central

Curcumin, a natural compound and ingredient in curry, has antiinflammatory, antioxidant, and anticarcinogenic properties. Previously, we reported that curcumin abrogated influenza virus infectivity by inhibiting hemagglutination (HA) activity. This study demonstrates a novel mechanism by which curcumin inhibits the infectivity of enveloped viruses. In all analyzed enveloped viruses, including the influenza virus, curcumin inhibited plaque formation. In contrast, the nonenveloped enterovirus 71 remained unaffected by curcumin treatment. We evaluated the effects of curcumin on the membrane structure using fluorescent dye (sulforhodamine B; SRB)-containing liposomes that mimic the viral envelope. Curcumin treatment induced the leakage of SRB from these liposomes and the addition of the influenza virus reduced the leakage, indicating that curcumin disrupts the integrity of the membranes of viral envelopes and of liposomes. When testing liposomes of various diameters, we detected higher levels of SRB leakage from the smaller-sized liposomes than from the larger liposomes. Interestingly, the curcumin concentration required to reduce plaque formation was lower for the influenza virus (approximately 100 nm in diameter) than for the pseudorabies virus (approximately 180 nm) and the vaccinia virus (roughly 335 × 200 × 200 nm). These data provide insights on the molecular antiviral mechanisms of curcumin and its potential use as an antiviral agent for enveloped viruses.

Wen, Hsiao-Wei; Ou, Jun-Lin; Chiou, Shyan-Song; Chen, Jo-Mei; Wong, Min-Liang; Hsu, Wei-Li

2013-01-01

52

[Human immunodeficiency virus infection - treatment beyond medication].  

PubMed

Human Immunodeficiency Virus (HIV) infection is presently considered a chronic disorder. Infected people need a thorough medical surveillance and chronic therapy, which affects families and other caregivers. Infected children are also affected by their parents' infection and by the stigma that is still associated with this particular illness. Regular meetings were organized for HIV infected children, their families and the health team with recreational and formative purposes. These meetings were evaluated in a strongly positive manner by all the intervenients. The goal to maintain these activities is proposed as a way of improving the follow-up and the prognosis of these children. PMID:21144321

Teixeira, Carla; Rodrigues, Paula; Cardoso, Cármen; Morais, Angélica; Sequeira, Fátima; Diz, Alcinda; Santos, M Carmo; Marques, Laura

2010-01-01

53

Multiple virus infections in the honey bee and genome divergence of honey bee viruses  

Microsoft Academic Search

Using uniplex RT-PCR we screened honey bee colonies for the presence of several bee viruses, including black queen cell virus (BQCV), deformed wing virus (DWV), Kashmir bee virus (KBV), and sacbrood virus (SBV), and described the detection of mixed virus infections in bees from these colonies. We report for the first time that individual bees can harbor four viruses simultaneously.

Yanping Chen; Yan Zhao; John Hammond; Hei-ti Hsu; Jay Evans; Mark Feldlaufer

2004-01-01

54

Adaptive response in hepatitis B virus infection.  

PubMed

Hepatitis B virus (HBV) is a major cause of acute and chronic liver inflammation worldwide. The immune response against the virus represents a key factor in determining infection outcome, in terms of both viral clearance and the perpetuation of liver damage. Significant advances have recently been achieved regarding the functions of antiviral CD8+ T cells, leading to a better understanding of their abnormalities during chronic infection as well as the pathways to be manipulated to reverse the immune impairment of chronic infection. In this review, we aimed to analyse the patterns of adaptive immunity that develop during acute infection and the profiles in chronic infection. In addition to CD8+ T cells, which are the best-described subset to date, we reviewed and commented on the direct and indirect roles of CD4+ T cells and B cells. PMID:24674098

Loggi, E; Gamal, N; Bihl, F; Bernardi, M; Andreone, P

2014-05-01

55

Virus Infections in Type 1 Diabetes  

PubMed Central

The precise etiology of type 1 diabetes (T1D) is still unknown, but viruses have long been suggested as a potential environmental trigger for the disease. However, despite decades of research, the body of evidence supporting a relationship between viral infections and initiation or acceleration of islet autoimmunity remains largely circumstantial. The most robust association with viruses and T1D involves enterovirus species, of which some strains have the ability to induce or accelerate disease in animal models. Several hypotheses have been formulated to mechanistically explain how viruses may affect islet autoimmunity and ?-cell decay. The recent observation that certain viral infections, when encountered at the right time and infectious dose, can prevent autoimmune diabetes illustrates that potential relationships may be more complex than previously thought. Here, we provide a concise summary of data obtained in mouse models and humans, and identify future avenues toward a better characterization of the association between viruses and T1D.

Coppieters, Ken T.; Boettler, Tobias; von Herrath, Matthias

2012-01-01

56

Ambient temperature and respiratory virus infection.  

PubMed

Respiratory viruses are important pediatric pathogens with pronounced seasonal patterns of circulation. Various hypotheses have been put forth to explain the seasonality of these infections, many involving environmental factors. This review summarizes the effect of temperature on the epidemicity of respiratory viruses, with an emphasis on epidemiological findings from large-scale metanalyses, laboratory-derived data using animal models and possible mechanisms to account for viral seasonality. PMID:24378933

Pica, Natalie; Bouvier, Nicole M

2014-03-01

57

Serologic and Infectivity Studies of Canine Sv-5 Virus (35012).  

National Technical Information Service (NTIS)

The recovery of parainfluenza SV-5 viruses from laboratory and military dogs with respiratory disease was previously reported. The virus was first isolated from rhesus monkey kidney cell cultures and subsequently from man. SV-5 virus appears to infect man...

E. C. Lazar L. J. Swango L. N. Binn

1970-01-01

58

Immune responses and Lassa virus infection.  

PubMed

Lassa fever is a hemorrhagic fever endemic to West Africa and caused by Lassa virus, an Old World arenavirus. It may be fatal, but most patients recover from acute disease and some experience asymptomatic infection. The immune mechanisms associated with these different outcomes have not yet been fully elucidated, but considerable progress has recently been made, through the use of in vitro human models and nonhuman primates, the only relevant animal model that mimics the pathophysiology and immune responses induced in patients. We discuss here the roles of the various components of the innate and adaptive immune systems in Lassa virus infection and in the control of viral replication and pathogenesis. PMID:23202504

Russier, Marion; Pannetier, Delphine; Baize, Sylvain

2012-11-01

59

Infection of potato mesophyll protoplasts with five plant viruses.  

PubMed

Methods are described for preparing potato mesophyll protoplasts that are suitable for infection with inocula of virus nucleoprotein or RNA. The protoplasts could be infected with four sap-transmissible viruses (tobacco mosaic, tobacco rattle, tobacco ringspot and tomato black ring viruses) and with potato leafroll virus, which is not saptransmissible. No differences were observed in ability to infect protoplasts with potato leafroll virus strains differing either in virulence in intact plants or in aphid transmissibility. PMID:24257766

Barker, H; Harrison, B D

1982-12-01

60

Pathogenesis of human immunodeficiency virus infection.  

PubMed Central

The lentivirus human immunodeficiency virus (HIV) causes AIDS by interacting with a large number of different cells in the body and escaping the host immune response against it. HIV is transmitted primarily through blood and genital fluids and to newborn infants from infected mothers. The steps occurring in infection involve an interaction of HIV not only with the CD4 molecule on cells but also with other cellular receptors recently identified. Virus-cell fusion and HIV entry subsequently take place. Following virus infection, a variety of intracellular mechanisms determine the relative expression of viral regulatory and accessory genes leading to productive or latent infection. With CD4+ lymphocytes, HIV replication can cause syncytium formation and cell death; with other cells, such as macrophages, persistent infection can occur, creating reservoirs for the virus in many cells and tissues. HIV strains are highly heterogeneous, and certain biologic and serologic properties determined by specific genetic sequences can be linked to pathogenic pathways and resistance to the immune response. The host reaction against HIV, through neutralizing antibodies and particularly through strong cellular immune responses, can keep the virus suppressed for many years. Long-term survival appears to involve infection with a relatively low-virulence strain that remains sensitive to the immune response, particularly to control by CD8+ cell antiviral activity. Several therapeutic approaches have been attempted, and others are under investigation. Vaccine development has provided some encouraging results, but the observations indicate the major challenge of preventing infection by HIV. Ongoing research is necessary to find a solution to this devastating worldwide epidemic. Images

Levy, J A

1993-01-01

61

The impact of hepatitis A virus infection on hepatitis C virus infection: a competitive exclusion hypothesis.  

PubMed

We address the observation that, in some cases, patients infected with the hepatitis C virus (HCV) are cleared of HCV when super-infected with the hepatitis A virus (HAV). We hypothesise that this phenomenon can be explained by the competitive exclusion principle, including the action of the immune system, and show that the inclusion of the immune system explains both the elimination of one virus and the co-existence of both infections for a certain range of parameters. We discuss the potential clinical implications of our findings. PMID:23192400

Amaku, Marcos; Coutinho, Francisco Antonio Bezerra; Chaib, Eleazar; Massad, Eduardo

2013-01-01

62

EXPERIMENTAL TRANSMISSION OF INFLUENZA VIRUS INFECTION IN MICE  

PubMed Central

Evidence has been presented that with the experimental model described, infected mice vary in their ability to transmit influenza virus infection. This variation is not explained by differences in titers of influenza virus in the nose, throat, trachea, or lungs of good transmitters. Older mice acquire transmitted influenza virus infection more readily than younger mice. Seasonal variations in the incidence of transmitted influenza virus infection occur.

Schulman, Jerome L.; Kilbourne, Edwin D.

1963-01-01

63

Paramecium bursaria Chlorella Virus 1 Proteome Reveals Novel Architectural and Regulatory Features of a Giant Virus  

PubMed Central

The 331-kbp chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) genome was resequenced and annotated to correct errors in the original 15-year-old sequence; 40 codons was considered the minimum protein size of an open reading frame. PBCV-1 has 416 predicted protein-encoding sequences and 11 tRNAs. A proteome analysis was also conducted on highly purified PBCV-1 virions using two mass spectrometry-based protocols. The mass spectrometry-derived data were compared to PBCV-1 and its host Chlorella variabilis NC64A predicted proteomes. Combined, these analyses revealed 148 unique virus-encoded proteins associated with the virion (about 35% of the coding capacity of the virus) and 1 host protein. Some of these proteins appear to be structural/architectural, whereas others have enzymatic, chromatin modification, and signal transduction functions. Most (106) of the proteins have no known function or homologs in the existing gene databases except as orthologs with proteins of other chloroviruses, phycodnaviruses, and nuclear-cytoplasmic large DNA viruses. The genes encoding these proteins are dispersed throughout the virus genome, and most are transcribed late or early-late in the infection cycle, which is consistent with virion morphogenesis.

Cerny, Ronald L.; Bauman, Andrew T.; Roach, Jared C.; Lane, Leslie C.; Agarkova, Irina V.; Wulser, Kurt; Yanai-Balser, Giane M.; Gurnon, James R.; Vitek, Jason C.; Kronschnabel, Bernard J.; Jeanniard, Adrien; Blanc, Guillaume; Upton, Chris; Duncan, Garry A.; McClung, O. William; Ma, Fangrui

2012-01-01

64

Pathogeneses of respiratory infections with virulent and attenuated vaccinia viruses  

Microsoft Academic Search

BACKGROUND: Respiratory infection with the neurovirulent vaccinia virus (VV) strain Western Reserve (WR) results in an acute infection of the lung followed by dissemination of the virus to other organs and causes lethality in mice. The mechanisms of lethality are not well-understood. In this study, we analyzed virus replication and host immune responses after intranasal infection with lethal and non-lethal

Daisuke Hayasaka; Francis A Ennis; Masanori Terajima

2007-01-01

65

Cytological effect of virus infection in five crop species  

Microsoft Academic Search

Meiotic abnormalities and pollen sterility due to virus infection in Capsicum annuum L., Carica papaya L., Lablab purpureus L., Lycopersicon esculentum L., and Solanum melongena L. were studied. Comparison in with unaffected plants showed that virus infected plants, asynapsis, multivalents and lower chiasma frequencies were present. Frequencies of chromosomal irregularities and pollen sterility were high in virus infected plants. Different

Atika Naz; G. KABIR; M. M. UD-DEEN

2008-01-01

66

Herpes Simplex Virus Infection in Pregnancy  

PubMed Central

Infection with herpes simplex is one of the most common sexually transmitted infections. Because the infection is common in women of reproductive age it can be contracted and transmitted to the fetus during pregnancy and the newborn. Herpes simplex virus is an important cause of neonatal infection, which can lead to death or long-term disabilities. Rarely in the uterus, it occurs frequently during the transmission delivery. The greatest risk of transmission to the fetus and the newborn occurs in case of an initial maternal infection contracted in the second half of pregnancy. The risk of transmission of maternal-fetal-neonatal herpes simplex can be decreased by performing a treatment with antiviral drugs or resorting to a caesarean section in some specific cases. The purpose of this paper is to provide recommendations on management of herpes simplex infections in pregnancy and strategies to prevent transmission from mother to fetus.

Straface, Gianluca; Selmin, Alessia; Zanardo, Vincenzo; De Santis, Marco; Ercoli, Alfredo; Scambia, Giovanni

2012-01-01

67

Herpes simplex virus infection in pregnancy.  

PubMed

Infection with herpes simplex is one of the most common sexually transmitted infections. Because the infection is common in women of reproductive age it can be contracted and transmitted to the fetus during pregnancy and the newborn. Herpes simplex virus is an important cause of neonatal infection, which can lead to death or long-term disabilities. Rarely in the uterus, it occurs frequently during the transmission delivery. The greatest risk of transmission to the fetus and the newborn occurs in case of an initial maternal infection contracted in the second half of pregnancy. The risk of transmission of maternal-fetal-neonatal herpes simplex can be decreased by performing a treatment with antiviral drugs or resorting to a caesarean section in some specific cases. The purpose of this paper is to provide recommendations on management of herpes simplex infections in pregnancy and strategies to prevent transmission from mother to fetus. PMID:22566740

Straface, Gianluca; Selmin, Alessia; Zanardo, Vincenzo; De Santis, Marco; Ercoli, Alfredo; Scambia, Giovanni

2012-01-01

68

Cellular scent of influenza virus infection.  

PubMed

Volatile organic compounds (VOCs) emanating from humans have the potential to revolutionize non-invasive diagnostics. Yet, little is known about how these compounds are generated by complex biological systems, and even less is known about how these compounds are reflective of a particular physiological state. In this proof-of-concept study, we examined VOCs produced directly at the cellular level from B lymphoblastoid cells upon infection with three live influenza virus subtypes: H9N2 (avian), H6N2 (avian), and H1N1 (human). Using a single cell line helped to alleviate some of the complexity and variability when studying VOC production by an entire organism, and it allowed us to discern marked differences in VOC production upon infection of the cells. The patterns of VOCs produced in response to infection were unique for each virus subtype, while several other non-specific VOCs were produced after infections with all three strains. Also, there was a specific time course of VOC release post infection. Among emitted VOCs, production of esters and other oxygenated compounds was particularly notable, and these may be attributed to increased oxidative stress resulting from infection. Elucidating VOC signatures that result from the host cells response to infection may yield an avenue for non-invasive diagnostics and therapy of influenza and other viral infections. PMID:24719290

Aksenov, Alexander A; Sandrock, Christian E; Zhao, Weixiang; Sankaran, Shankar; Schivo, Michael; Harper, Richart; Cardona, Carol J; Xing, Zheng; Davis, Cristina E

2014-05-01

69

Mental Status after West Nile Virus Infection  

Microsoft Academic Search

Mental status after acute West Nile virus infection has not been examined objectively. We compared Telephone Interview for Cognitive Status scores of 116 patients with West Nile fever or West Nile neuroinvasive disease. Mental status was poorer and cognitive complaints more frequent with West Nile neuroinvasive disease (p = 0.005).

Kathleen Y. Haaland; Joseph Sadek; Steven Pergam; Leonor A. Echevarria; Larry E. Davis; Diane Goade; Joanne Harnar; Robert A. Nofchissey; C. Mack Sewel; Paul Ettestad

70

Mitochondrial dysfunction in hepatitis C virus infection  

Microsoft Academic Search

The mechanisms of liver injury in chronic hepatitis C virus (HCV) infection are poorly understood though HCV induces a state of hepatic oxidative stress that is more pronounced than that present in many other inflammatory diseases. This mini-review will focus on recent findings revealing an unexpected role of mitochondria in providing a central role in the innate immunity and in

C. Piccoli; R. Scrima; A. D'Aprile; M. Ripoli; L. Lecce; D. Boffoli; N. Capitanio

2006-01-01

71

Infection of Plants by Tobacco Mosaic Virus.  

ERIC Educational Resources Information Center

Provides three exercises that introduce high school and college students to a common strain of the tobacco mosaic virus and the study of some basic biological processes. Activities involve inoculation of plants and observing and recording symptom development in infected plants. (DDR)

McDaniel, Larry; Maratos, Marina; Farabaugh, Joan

1998-01-01

72

Emerging and reemerging influenza virus infections.  

PubMed

Influenza A virus infection occurs in many species. Wild waterfowl harbor the widest variety of influenza A viruses and serve as a constant reservoir for the emergence of new viruses. Highly pathogenic avian influenza, or "fowl plague," has been a known poultry disease for more than 130 years. It continues to emerge and reemerge, but global changes in trade and poultry production have expanded the impact and geographic range of these outbreaks. One subtype of highly pathogenic avian influenza, H5N1, has infected poultry on several continents as well as many people, leading to a human disease that is markedly different from seasonal influenza and that is associated with high mortality. PMID:20080485

Shinya, K; Makino, A; Kawaoka, Y

2010-01-01

73

Update on oral herpes virus infections.  

PubMed

Oral herpes virus infections (OHVIs) are among the most common mucosal disorders encountered by oral health care providers. These infections can affect individuals at any age, from infants to the elderly, and may cause significant pain and dysfunction. Immunosuppressed patients may be at increased risk for serious and potential life-threatening complications caused by OHVIs. Clinicians may have difficulty in diagnosing these infections because they can mimic other conditions of the oral mucosa. This article provides oral health care providers with clinically relevant information regarding etiopathogenesis, diagnosis, and management of OHVIs. PMID:24655522

Balasubramaniam, Ramesh; Kuperstein, Arthur S; Stoopler, Eric T

2014-04-01

74

Oral Manifestations of Human Immunodeficiency Virus Infection  

PubMed Central

The AIDS epidemic continues. All health-care workers, including physicians and dental personnel, may be instrumental in recognizing risk factors associated with Acquired Immunodeficiency Syndrome (AIDS) and Human Immunodeficiency Virus (HIV) infection. Oral signs and symptoms of HIV infection may be the first presentation of the disease or may develop during the course of the disease and require management. Knowledge of the signs, symptoms and associated infections and tumours is needed to assist in recognition, diagnosis, and treatment. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7Figure 8Figure 9Figure 10Figure 11Figure 12Figure 13

Epstein, Joel B.; Mathias, Richard G.

1988-01-01

75

Human Infection with Newcastle Virus.  

National Technical Information Service (NTIS)

The Newcastle infection of humans shows all the characteristics of zoonosis. As yet the transmission from human to human or reverse transmission from human to fowl is acknowledged. It is also always concerned in dull ending ramifications from its infectio...

G. Schoop

1965-01-01

76

The cell biology of Chikungunya virus infection.  

PubMed

Chikungunya virus (CHIKV) infection causes a disease which appears to affect multiple cell types and tissues. The acute phase is manifested by a non-fatal febrile illness, polyarthralgia and maculopapular rashes in adults, but with recurrent arthralgia that may linger for months during convalescence. The issue of cellular and tissue tropism of CHIKV has elicited interest primarily because of this lingering incapacitating chronic joint pain, as well as clear encephalopathy in severe cases among neonates during the re-emergence of the virus in recent epidemics. The principle cell types productively infected by CHIKV are skin fibroblasts, epithelial cells and lymphoid tissues. There is controversy as to whether CHIKV productively infects haematopoietic cells and neurones/glia. CHIKV infection triggers rapid and robust innate immune responses which quickly clears the acute phase infection. However, significant acute as well as chronic infection of less obvious cell types, such as monocytes, neurones/glia or even CNS neural progenitors may conceivably occur. There is therefore a need to ascertain the full range potential of CHIKV tropism, fully understand the cellular responses triggered during the acute the convalescent phases, and explore possible cell types that might be the source of chronic problems associated with CHIKV infection. PMID:22686853

Tang, Bor Luen

2012-09-01

77

New perspectives in Respiratory Syncitial Virus infection.  

PubMed

Respiratory syncitial virus (RSV) is the most common cause of lower respiratory tract infections (LRTI) in children worldwide and it is associated with significant childhood morbidity. Acute infection may result in respiratory failure with varying degrees of severity, and increasing evidence supports a role of RSV infection as a key determinant for the development of subsequent chronic respiratory disease. Independent predictors of RSV severity include; prematurity, congenital heart disease, cystic fibrosis, immune defects and neuromuscular disorders. Passive immunization with palivizumab has proven to be safe and effective for preventing RSV hospitalization in infants at higher risk of acquiring severe RSV infection, but its expense and cumbersome monthly intravenous delivery schedule make it inaccessible to many. Furthermore, implementing prophylaxis in 32- to 35-week-gestational age infants and the mode of its administration still represent areas of uncertainty. In this review, we describe several aspects of RSV infection and analyze recent advances in the assessment of cost-effective palivizumab prophylaxis. PMID:24059554

Del Vecchio, Antonio; Ferrara, Teresa; Maglione, Marco; Capasso, Letizia; Raimondi, Francesco

2013-10-01

78

Human Dendritic Cells as Targets of Dengue Virus Infection  

Microsoft Academic Search

Dengue virus infections are an emerging global threat. Severe dengue infection is manifested as dengue hemorrhagic fever and dengue shock syndrome, both of which can be fatal complications. Factors predisposing to complicated disease and pathogenesis of severe infections are discussed. Using immunohistochemistry, immunofluorescence, flow cytometry, and ELISA techniques, we studied the cellular targets of dengue virus infection, at both the

Mary Marovich; Geraldine Grouard-Vogel; Mark Louder; Michael Eller; Wellington Sun; Shuenn-Ju Wu; Ravithat Putvatana; Gerald Murphy; Boonrat Tassaneetrithep; Timothy Burgess; Deborah Birx; Curtis Hayes; Sarah Schlesinger-Frankel; John Mascola; M. Marovitch

2001-01-01

79

Epidemiological features and economical importance of bovine virus diarrhoea virus (BVDV) infections  

Microsoft Academic Search

Infections with bovine virus diarrhoea virus (BVDV) are widespread throughout the world. Although the prevalence of infection varies among surveys, the infection tends to be endemic in many populations, reaching a maximum level of 1–2% of the cattle being persistently infected (PI) and 60–85% of the cattle being antibody positive. Persistently infected cattle are the main source for transmission of

Hans Houe

1999-01-01

80

Avian influenza: mixed infections and missing viruses.  

PubMed

A high prevalence and diversity of avian influenza (AI) viruses were detected in a population of wild mallards sampled during summer 2011 in California, providing an opportunity to compare results obtained before and after virus culture. We tested cloacal swab samples prior to culture by matrix real-time PCR, and by amplifying and sequencing a 640bp portion of the hemagglutinin (HA) gene. Each sample was also inoculated into embryonated chicken eggs, and full genome sequences were determined for cultured viruses. While low matrix Ct values were a good predictor of virus isolation from eggs, samples with high or undetectable Ct values also yielded isolates. Furthermore, a single passage in eggs altered the occurrence and detection of viral strains, and mixed infections (different HA subtypes) were detected less frequently after culture. There is no gold standard or perfect reference comparison for surveillance of unknown viruses, and true negatives are difficult to distinguish from false negatives. This study showed that sequencing samples prior to culture increases the detection of mixed infections and enhances the identification of viral strains and sequences that may have changed or even disappeared during culture. PMID:23921843

Lindsay, LeAnn L; Kelly, Terra R; Plancarte, Magdalena; Schobel, Seth; Lin, Xudong; Dugan, Vivien G; Wentworth, David E; Boyce, Walter M

2013-08-01

81

Sensory polymyeloradiculopathy associated with Toscana virus infection.  

PubMed

Sandfly viruses are arthropod-borne viruses that are endemic in the Mediterranean basin. The Toscana virus (TOSV) is the only serotype of sandfly viruses known to cause neurological symptoms in humans, usually aseptic meningitis or meningoencephalitis. We report a case of a 39-year-old man who was admitted to our department with progressive paresthesias of the lower limbs followed by dysesthesias of the upper thorax after a hiking trip to the Netherlands. The patient had also been suffering from epididymitis for several weeks before the neurological symptoms appeared but was treated by antibiotics accordingly. Lumber puncture results demonstrated mononuclear pleocytosis with elevated protein levels. MRI of the lumbar spine revealed polymyeloradiculopathy. Positive IgM antibodies against the Toscana serotype of sandfly virus were discovered in the patient's blood and CSF. There was also evidence for a recent infection by Mycoplasma pneumoniae. The patient was treated conservatively with improvement in his neurological state. To the best of our knowledge, this is the first case report of an association between TOSV infection and polymyeloradiculopathy. PMID:24081884

Gonen, Ofer Michael; Sacagiu, Tzvika

2013-10-01

82

Cells in Dengue Virus Infection In Vivo  

PubMed Central

Dengue has been recognized as one of the most important vector-borne emerging infectious diseases globally. Though dengue normally causes a self-limiting infection, some patients may develop a life-threatening illness, dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS). The reason why DHF/DSS occurs in certain individuals is unclear. Studies in the endemic regions suggest that the preexisting antibodies are a risk factor for DHF/DSS. Viremia and thrombocytopenia are the key clinical features of dengue virus infection in patients. The amounts of virus circulating in patients are highly correlated with severe dengue disease, DHF/DSS. Also, the disturbance, mainly a transient depression, of hematological cells is a critical clinical finding in acute dengue patients. However, the cells responsible for the dengue viremia are unresolved in spite of the intensive efforts been made. Dengue virus appears to replicate and proliferate in many adapted cell lines, but these in vitro properties are extremely difficult to be reproduced in primary cells or in vivo. This paper summarizes reports on the permissive cells in vitro and in vivo and suggests a hematological cell lineage for dengue virus infection in vivo, with the hope that a new focus will shed light on further understanding of the complexities of dengue disease.

Noisakran, Sansanee; Onlamoon, Nattawat; Songprakhon, Pucharee; Hsiao, Hui-Mien; Chokephaibulkit, Kulkanya; Perng, Guey Chuen

2010-01-01

83

Human papilloma virus associated with genital infection.  

PubMed

Genital human papillomavirus (HPV) infections are among the most common sexually transmitted diseases. HPV is associated with a spectrum of diseases ranging from benign vulgar verrucae and condylomata accuminata to malignant cancers of the cervix, vulva, anus and penis. Genital HPV is in most cases transmitted sexually, but non-sexual routes of transmission, such as perinatal and autoinoculation, are possible. Men can be a reservoir of the virus that lives in latent or subclinical form on genital mucosa. Such an asymptomatic infection may be an oncogenic factor in the development of cervical cancer Colposcopic examination of the genitalia after the application of 3-5% acetic acid is a reliable method for the identification of subclinical HPV infection. Successful therapy of anogenital warts is characterized by their complete clearance, as well as by the lack of recurrence. Current treatments do not reliably eradicate HPV infections. The diagnosis and therapy of HPV infection in men is potentially beneficial because the eradication of penile HPV infection may decrease the reservoir of the virus. PMID:18982779

Ljubojevi?, Suzana; Lipozenci?, Jasna; Grgec, Dragana-Ljubojevi?; Prstaci?, Ratko; Skerlev, Michael; Mokos, Zrinka Bukvi?

2008-09-01

84

Neutralizing antibodies in hepatitis C virus infection.  

PubMed

Hepatitis C virus (HCV) is a major cause of hepatitis world-wide. The majority of infected individuals develop chronic hepatitis which can then progress to liver cirrhosis and hepatocellular carcinoma. Spontaneous viral clearance occurs in about 20%-30% of acutely infected individuals and results in resolution of infection without sequaelae. Both viral and host factors appear to play an important role for resolution of acute infection. A large body of evidence suggests that a strong, multispecific and long-lasting cellular immune response appears to be important for control of viral infection in acute hepatitis C. Due too the lack of convenient neutralization assays, the impact of neutralizing responses for control of viral infection had been less defined. In recent years, the development of robust tissue culture model systems for HCV entry and infection has finally allowed study of antibody-mediated neutralization and to gain further insights into viral targets of host neutralizing responses. In addition, detailed analysis of antibody-mediated neutralization in individual patients as well as cohorts with well defined viral isolates has enabled the study of neutralizing responses in the course of HCV infection and characterization of the impact of neutralizing antibodies for control of viral infection. This review will summarize recent progress in the understanding of the molecular mechanisms of antibody-mediated neutralization and its impact for HCV pathogenesis. PMID:17828813

Zeisel, Mirjam-B; Fafi-Kremer, Samira; Fofana, Isabel; Barth, Heidi; Stoll-Keller, Francoise; Doffoel, Michel; Baumert, Thomas-F

2007-09-28

85

Management of hepatitis C virus infection in HIV\\/HCV co-infected patients: Clinical review  

Microsoft Academic Search

Nearly one fourth of individuals with human immunodeficiency virus (HIV) infection have hepatitis C virus (HCV) infection in the US and Western Europe. With the availability of highly active antiretroviral therapy and the consequent reduction in opportunistic infections, resulting in the prolongation of the life span of HIV-infected patients, HCV co-infection has emerged as a significant factor influencing the survival

Ashwani K Singal; Bhupinderjit S Anand

86

Psoralen inactivation of influenza and herpes simplex viruses and of virus-infected cells  

SciTech Connect

Psoralen compounds covalently bind to nucleic acids when irradiated with long-wavelength ultraviolet light. This treatment can destroy the infectivity of deoxyribonucleic acid and ribonucleic acid viruses. Two psoralen compounds, 4'-hydroxymethyltrioxsalen and 4'-aminomethyltrioxsalen, were used with long-wavelength ultraviolet light to inactivate cell-free herpes simplex and influenza viruses and to render virus-infected cells noninfectious. This method of inactivation was compared with germicidal (short-wavelength) ultraviolet light irradiation. The antigenicity of the treated, virus-infected, antigen-bearing cells was examined by immunofluorescence and radioimmunoassay and by measuring the capacity of the herpes simplex virus-infected cells to stimulate virus-specific lymphocyte proliferation. The infectivity of the virus-infected cells could be totally eliminated without altering their viral antigenicity. The use of psoralen plus long-wavelength ultraviolet light is well suited to the preparation of noninfectious virus antigens and virus antigen-bearing cells for immunological assays.

Redfield, D.C.; Richman, D.D.; Oxman, M.N.; Kronenberg, L.H.

1981-06-01

87

Tetherin upregulation in simian immunodeficiency virus-infected macaques.  

PubMed

Here we show that simian immunodeficiency virus (SIV) infection of rhesus macaques results in rapid upregulation of tetherin (BST-2 or CD317) on peripheral blood lymphocytes, including the CD4(+) CCR5(+) T cell targets of virus infection, with a peak of induction that coincides with peak alpha interferon (IFN-?) levels in plasma, and that tetherin remains above baseline levels throughout chronic infection. These observations are consistent with a role for tetherin in innate immunity to immunodeficiency virus infection. PMID:24109219

Rahmberg, Andrew R; Neidermyer, William J; Breed, Matthew W; Alvarez, Xavier; Midkiff, Cecily C; Piatak, Michael; Lifson, Jeffrey D; Evans, David T

2013-12-01

88

Tetherin Upregulation in Simian Immunodeficiency Virus-Infected Macaques  

PubMed Central

Here we show that simian immunodeficiency virus (SIV) infection of rhesus macaques results in rapid upregulation of tetherin (BST-2 or CD317) on peripheral blood lymphocytes, including the CD4+ CCR5+ T cell targets of virus infection, with a peak of induction that coincides with peak alpha interferon (IFN-?) levels in plasma, and that tetherin remains above baseline levels throughout chronic infection. These observations are consistent with a role for tetherin in innate immunity to immunodeficiency virus infection.

Rahmberg, Andrew R.; Neidermyer, William J.; Breed, Matthew W.; Alvarez, Xavier; Midkiff, Cecily C.; Piatak, Michael; Lifson, Jeffrey D.

2013-01-01

89

Alterations to influenza virus hemagglutinin cytoplasmic tail modulate virus infectivity.  

PubMed Central

The influenza virus hemagglutinin (HA) contains a cytoplasmic domain that consists of 10 to 11 amino acids, of which five residues have sequence identity for 10 of 13 HA subtypes. To investigate properties of these conserved residues, oligonucleotide-directed mutagenesis was performed, using an HA cDNA of influenza virus A/Udorn/72 (H3N2) to substitute the conserved cysteine residues with other residues, to delete the three C-terminal conserved residues, or to remove the entire cytoplasmic domain. The altered HAs were expressed in eukaryotic cells, and the rates of intracellular transport were examined. It was found that substitution of either conserved cysteine residue within the cytoplasmic domain did not affect the rate of intracellular transport, whereas deletion of residues within the C-terminal domain resulted in delayed cell surface expression. All the altered HAs were biologically active in hemadsorption and fusion assays. To investigate whether the wild-type HA and HAs with altered cytoplasmic tails could complement the influenza virus temperature-sensitive transport-defective HA mutant A/WSN/33 ts61S, the HA cDNAs were expressed by using a transient expression system and released virus was assayed by plaque analysis. The wild-type HA expression resulted in a release of approximately 10(3) PFU of virus per ml. Antibody neutralization of complemented virus indicated that the infectivity was due to incorporation of wild-type H3 HA into ts61S virions. Sucrose density gradient analysis of released virions showed that each of the HA cytoplasmic domain mutants was incorporated into virus particles. Virions containing HAs with substitution of the cysteine residues in the cytoplasmic domain were found to be infectious. However, no infectivity could be detected from virions containing HAs that had deletions in their cytoplasmic domains. Possible roles of the HA cytoplasmic domain in forming protein-protein interactions in virions and their involvement in the initiation of the infection process in cells are discussed. Images

Simpson, D A; Lamb, R A

1992-01-01

90

Transfusion-transmitted hepatitis B virus infection.  

PubMed

Hepatitis B virus (HBV) remains a major risk of transfusion-transmitted infection due to the pre-seroconversion window period (WP), infection with immunovariant viruses, and with occult carriage of HBV infection (OBI). Reduction of HBV residual risk depends upon developing more sensitive HBV surface antigen (HBsAg) tests, adopting anti-HBc screening when appropriate, and implementing HBV nucleic acid testing (NAT), either in minipools or more efficiently in individual samples. HBV NAT combines the ability to significantly reduce the window period and to detect occult HBV carriage substantiating decades of clinical observation that HBsAg-negative/anti-HBc-positive blood could transmit HBV. Clinical observations suggest limited transmission rate of occult HBV compared to WP. Low transmission rate might be related to low viral load observed in OBIs or to the presence of mutants associated with occult carriage. OBIs carrying detectable anti-HBs ( approximately 50%) are essentially not infectious by transfusion. However, recent data suggest that the neutralizing capacity of low anti-HBs may be inefficient when overcome by exposure to high viral load. Anti-HBc blood units without detectable anti-HBs appear moderately infectious except in immunocompromised recipients. Immunodeficient elderly and patients receiving immunosuppressive treatments may be susceptible to infection with lower infectious dose even in the presence of anti-HBs. The immune status of blood recipients should be taken into consideration when investigating "post-transfusion" HBV infection. Pre-transfusion testing and post-transfusion long-term follow-up of recipients, and molecular analysis of the virus infecting both donor and recipient are critical to definitively incriminate transfusion in the transmission of HBV. PMID:19615780

Candotti, Daniel; Allain, Jean-Pierre

2009-10-01

91

Host Species Barriers to Influenza Virus Infections  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required: Most emerging infectious diseases in humans originate from animal reservoirs; to contain and eradicate these diseases we need to understand how and why some pathogens become capable of crossing host species barriers. Influenza virus illustrates the interaction of factors that limit the transmission and subsequent establishment of an infection in a novel host species. Influenza species barriers can be categorized into virus-host interactions occurring within individuals and host-host interactions, either within or between species, that affect transmission between individuals. Viral evolution can help surmount species barriers, principally by affecting virus-host interactions; however, evolving the capability for sustained transmission in a new host species represents a major adaptive challenge because the number of mutations required is often large.

Thijs Kuiken (Erasmus Medical Center;Department of Virology); Edward C. Holmes (Pennsylvania State University;Department of Biology); John McCauley (Compton Laboratory;Institute for Animal Health); Guus F. Rimmelzwaan (Erasmus Medical Center;Department of Virology); Catherine S. Williams (Pennsylvania State University;Department of Biology); Bryan T. Grenfell (National Institutes of Health, Pennsylvania State University;Fogarty International Center)

2006-04-21

92

Influenza A virus infections in swine: pathogenesis and diagnosis.  

PubMed

Influenza has been recognized as a respiratory disease in swine since its first appearance concurrent with the 1918 "Spanish flu" human pandemic. All influenza viruses of significance in swine are type A, subtype H1N1, H1N2, or H3N2 viruses. Influenza viruses infect epithelial cells lining the surface of the respiratory tract, inducing prominent necrotizing bronchitis and bronchiolitis and variable interstitial pneumonia. Cell death is due to direct virus infection and to insult directed by leukocytes and cytokines of the innate immune system. The most virulent viruses consistently express the following characteristics of infection: (1) higher or more prolonged virus replication, (2) excessive cytokine induction, and (3) replication in the lower respiratory tract. Nearly all the viral proteins contribute to virulence. Pigs are susceptible to infection with both human and avian viruses, which often results in gene reassortment between these viruses and endemic swine viruses. The receptors on the epithelial cells lining the respiratory tract are major determinants of infection by influenza viruses from other hosts. The polymerases, especially PB2, also influence cross-species infection. Methods of diagnosis and characterization of influenza viruses that infect swine have improved over the years, driven both by the availability of new technologies and by the necessity of keeping up with changes in the virus. Testing of oral fluids from pigs for virus and antibody is a recent development that allows efficient sampling of large numbers of animals. PMID:24363301

Janke, B H

2014-03-01

93

Epstein-Barr virus infection and associated diseases in children  

Microsoft Academic Search

Epstein-Barr virus (EBV), an ubiquitous human B lymphotropic virus, is the cause of infectious mononucleosis. Moreover, EBV infection can be followed by lymphoproliferative diseases in patients with inherited and acquired immunodeficiencies. Primary EBV infection may be a threat to all children after marrow or organ transplantation or those receiving chronic immunosuppressive treatment for various other reasons. The virus has been

V. Schuster; H. W. Kreth

1992-01-01

94

Endemic mycosis complicating human immunodeficiency virus infection.  

PubMed Central

Persons infected with the human immunodeficiency virus are prone to the development of many fungal diseases. Normal hosts with intact immunity usually recover from infection by these less-invasive fungi. In persons with compromised T-cell-mediated immunity, however, widespread dissemination from a pulmonary focus occurs. In this review, we discuss the epidemiology, clinical manifestations, diagnosis, and treatment of the three major North American mycoses, histoplasmosis, blastomycosis, and coccidioidomycosis. In most cases, amphotericin B is the initial drug of choice, followed by one of the azoles for lifelong maintenance therapy.

Sarosi, G A; DAvies, S F

1996-01-01

95

Prevention of respiratory syncytial virus infection  

PubMed Central

Respiratory syncytial virus (RSV) infection is the leading cause of lower respiratory tract infection in young children, with significant numbers of premature infants and those with other risk factors requiring hospitalization in Canada each year. Palivizumab, an RSV-specific monoclonal antibody, can reduce the hospitalization rate and severity of illness for a small group of high-risk or premature infants during their first RSV season. The present statement reviews the published literature and provides recommendations regarding its use in premature and other at-risk infants, for Canadian physicians.

Samson, L

2009-01-01

96

Pathogenesis of transplacental virus infection: pestivirus replication in the placenta and fetus following respiratory infection  

Microsoft Academic Search

Although transplacental virus infections account for considerable morbidity and mortality in both animals and humans, very little is so far known about the pathways whereby virus reaches the conceptus, the subsequent virus–host interactions in the early phases of the infections, and the establishment of persistent non-lethal infection. Using a natural animal model we recently demonstrated that bovine pestivirus can spread

Somchai Swasdipan; Michael McGowan; Nancy Phillips; Helle Bielefeldt-Ohmann

2002-01-01

97

Clinical and biological differences between recurrent herpes simplex virus and varicella-zoster virus infections  

SciTech Connect

The major features that distinguish recurrent herpes simplex virus infections from zoster are illustrated in this article by two case histories. The clinical and epidemiologic features that characterize recurrent herpes simplex virus and varicella-zoster virus infections are reviewed. It is noted that herpesvirus infections are more common and severe in patients with cellular immune deficiency. Each virus evokes both humoral and cellular immune response in the course of primary infection. DNA hybridization studies with RNA probes labelled with sulfur-35 indicate that herpes simplex viruses persist within neurons, and that varicella-zoster virus is found in the satellite cells that encircle the neurons.

Straus, S.E. (National Institute of Allergy and Infectious Diseases, Bethesda, MD (USA))

1989-12-01

98

Neurologic manifestations of varicella zoster virus infections  

Microsoft Academic Search

Varicella zoster virus (VZV) causes acute viral exanthema in childhood, becomes latent, and can reactivate years later to\\u000a produce neurologic disease. Primary VZV infection is associated with acute cerebellitis and stroke, particularly in childhood.\\u000a VZV reactivation may result in neuropathy, myelitis, stroke, and encephalitis, the latter two syndromes the result of small\\u000a and large vessel vasculopathy. Prompt diagnosis and treatment

Catherine Amlie-Lefond; Burk Jubelt

2009-01-01

99

West Nile Virus: Biology, Transmission, and Human Infection  

PubMed Central

Summary: West Nile Virus was introduced into the Western Hemisphere during the late summer of 1999 and has been causing significant and sometimes severe human diseases since that time. This article briefly touches upon the biology of the virus and provides a comprehensive review regarding recent discoveries about virus transmission, virus acquisition, and human infection and disease.

Colpitts, Tonya M.; Conway, Michael J.; Montgomery, Ruth R.

2012-01-01

100

Structural Insight into African Horsesickness Virus Infection  

PubMed Central

African horsesickness (AHS) is a devastating disease of horses. The disease is caused by the double-stranded RNA-containing African horsesickness virus (AHSV). Using electron cryomicroscopy and three-dimensional image reconstruction, we determined the architecture of an AHSV serotype 4 (AHSV-4) reference strain. The structure revealed triple-layered AHS virions enclosing the segmented genome and transcriptase complex. The innermost protein layer contains 120 copies of VP3, with the viral polymerase, capping enzyme, and helicase attached to the inner surface of the VP3 layer on the 5-fold axis, surrounded by double-stranded RNA. VP7 trimers form a second, T=13 layer on top of VP3. Comparative analyses of the structures of bluetongue virus and AHSV-4 confirmed that VP5 trimers form globular domains and VP2 trimers form triskelions, on the virion surface. We also identified an AHSV-7 strain with a truncated VP2 protein (AHSV-7 tVP2) which outgrows AHSV-4 in culture. Comparison of AHSV-7 tVP2 to bluetongue virus and AHSV-4 allowed mapping of two domains in AHSV-4 VP2, and one in bluetongue virus VP2, that are important in infection. We also revealed a protein plugging the 5-fold vertices in AHSV-4. These results shed light on virus-host interactions in an economically important orbivirus to help the informed design of new vaccines.

Manole, Violeta; Laurinmaki, Pasi; Van Wyngaardt, Wouter; Potgieter, Christiaan A.; Wright, Isabella M.; Venter, Gert J.; van Dijk, Alberdina A.; Sewell, B. Trevor

2012-01-01

101

Orthopox virus infections in Eurasian wild rodents.  

PubMed

The genus Orthopoxvirus includes variola (smallpox) virus and zoonotic cowpox virus (CPXV). All orthopoxviruses (OPV) are serologically cross-reactive and cross-protective, and after the cessation of smallpox vaccination, CPXV and other OPV infections represent an emerging threat to human health. In this respect CPXV, with its reservoir in asymptomatically infected wild rodents, is of special importance. In Europe, clinical cowpox has been diagnosed in both humans and animals. The main objective of this study was to elucidate the prevalence of OPV infections in wild rodents in different parts of Eurasia and to compare the performance of three real-time polymerase chain reaction (PCR) methods in detecting OPV DNA in wildlife samples. We investigated 962 wild rodents from Northern Europe (Finland), Central Europe (Germany), and Northern Asia (Siberia, Russia) for the presence of OPV antibodies. According to a CPXV antigen-based immunofluorescence assay, animals from 13 of the 17 locations (76%) showed antibodies. Mean seroprevalence was 33% in Finland (variation between locations 0%-69%), 32% in Germany (0%-43%), and 3.2% (0%-15%) in Siberia. We further screened tissue samples from 513 of the rodents for OPV DNA using up to three real-time PCRs. Three rodents from two German and one Finnish location were OPV DNA positive. The amplicons were 96% to 100% identical to available CPXV sequences. Further, we demonstrated OPV infections as far east as the Baikal region and occurring in hamster and two other rodent species, ones previously unnoticed as possible reservoir hosts. Based on serological and PCR findings, Eurasian wild rodents are frequently but nonpersistently infected with OPVs. Results from three real-time PCR methods were highly concordant. This study extends the geographic range and wildlife species diversity in which OPV (or CPXV) viruses are naturally circulating. PMID:21453121

Kinnunen, Paula M; Henttonen, Heikki; Hoffmann, Bernd; Kallio, Eva R; Korthase, Christian; Laakkonen, Juha; Niemimaa, Jukka; Palva, Airi; Schlegel, Mathias; Ali, Hanan Sheikh; Suominen, Paula; Ulrich, Rainer G; Vaheri, Antti; Vapalahti, Olli

2011-08-01

102

Human immunodeficiency virus, herpes virus infections, and pulmonary vascular disease  

PubMed Central

The following state-of-the-art seminar was delivered as part of the Aspen Lung Conference on Pulmonary Hypertension and Vascular Diseases held in Aspen, Colorado in June 2012. This paper will summarize the lecture and present results from a nonhuman primate model of infection with Simian (Human) Immunodeficiency Virus - nef chimeric virions as well as the idea that polymorphisms in the HIV-1 nef gene may be driving the immune response that results in exuberant inflammation and aberrant endothelial cell (EC) function. We will present data gathered from primary HIV nef isolates where we tested the biological consequences of these polymorphisms and how their presence in human populations may predict patients at risk for developing this disease. In this article, we also discuss how a dysregulated immune system, in conjunction with a viral infection, could contribute to pulmonary arterial hypertension (PAH). Both autoimmune diseases and some viruses are associated with defects in the immune system, primarily in the function of regulatory T cells. These T-cell defects may be a common pathway in the formation of plexiform lesions. Regardless of the route by which viruses may lead to PAH, it is important to recognize their role in this rare disease.

Flores, Sonia C.; Almodovar, Sharilyn

2013-01-01

103

Management of herpes simplex and varicella-zoster virus infections.  

PubMed Central

Herpes simplex virus and varicella-zoster virus are common infections and are seen frequently in clinical practice. Infection with these viruses results in cutaneous lesions that may be diagnosed clinically, but widely available laboratory testing is useful for confirmation. Asymptomatic herpes simplex virus shedding, or "subclinical reactivation," likely occurs in all persons infected with herpes simplex virus and results in the transmission of virus despite the absence of signs or symptoms that suggest active infection. Oral and intravenous acyclovir are effective in treating initial and recurrent herpes simplex and varicella-zoster virus infections. The daily administration of oral acyclovir as suppressive therapy is effective in patients with frequently recurring genital infection with herpes simplex virus by reducing the number of symptomatic recurrences and the frequency of asymptomatic virus shedding. Two new antiviral agents, famciclovir and valacyclovir hydrochloride, have been approved for the short-term treatment of recurrent genital herpes simplex virus and recurrent zoster in nonimmunocompromised hosts. Famciclovir and valacyclovir demonstrate superior pharmacokinetics compared with acyclovir and allow for less frequent daily dosing with higher achievable serum drug concentrations. The attenuated live varicella virus vaccine is now available in the United States and prevents primary varicella-zoster virus infection in susceptible children and adults.

Erlich, K S

1997-01-01

104

Viral Protein Synthesis in Cowpea Mosaic Virus Infected Protoplasts.  

National Technical Information Service (NTIS)

Some aspects of cowpea mosaic virus (CPMV) multiplication in cowpea mesophyll protoplasts were studied. The detection and characterization of proteins whose synthesis is induced or is stimulated upon virus infection was performed with the aid of radioacti...

P. Rottier

1980-01-01

105

Infectivity of algal viruses studied by chlorophyll fluorescence.  

PubMed

Algal virus infection proceeds via the specific recognition of the host cell wall, penetration of the cell wall and transfer of genetic material into the cytoplasm of the host cell. This process is similar to that which occurs when bacteriophage infect bacteria so that techniques and concepts developed to study bacteriophage are applicable to algal virus studies. By measuring virus-induced changes in chlorophyll fluorescence we have redefined classical studies on the distribution of infectivity. We show that infectivity does not follow a Poisson distribution with a fixed mean, n. By analysing the infectivity of algal viruses over a broad range of virus:cell ratios we have obtained a corrected Poisson distribution that reflects the probability of multiple virus particles attached per cell and is equally applicable to algal viruses and bacteriophage. PMID:7595395

Rohozinski, J; Patil, P N; Seaton, G G

1995-11-01

106

Hepatitis C virus infection and autoimmune diseases  

PubMed Central

Hepatitis C virus (HCV) infection is associated with a number of extrahepatic disorders. The most studied conditions associated with HCV are type II mixed cryoglobulinemia and B cell lymphoma. However, many reports suggest that HCV might also be associated with a number of autoimmune disorders, both organ-specific and not organ-specific. Although concomitant treatment of HCV infection is a confounding factor when ascertaining the actual role of HCV in inducing autoimmune disease, a considerable amount of experimental data indicates that HCV is able to subvert the immune system and consequently induce autoimmunity. In the present review, we report a series of observations which associate chronic HCV infection with the onset of autoimmune disorders.

Paroli, Marino; Iannucci, Gino; Accapezzato, Daniele

2012-01-01

107

Pathogenesis of human immunodeficiency virus infection and prospects for control.  

PubMed Central

In just six years after the initial description of the acquired immunodeficiency syndrome, much has been learned about the etiologic agent, the human immunodeficiency virus. The pathogenic mechanisms utilized by this virus to infect selectively and persistently T4+ lymphocytes and monocyte/macrophages, leading to immunodeficiency and neurologic dysfunction, are slowly becoming clear. Better understanding of the pathogenesis of human immunodeficiency virus infection is essential for the rational design of therapeutic and preventive strategies to combat this deadly virus.

Ho, D. D.; Kaplan, J. C.

1987-01-01

108

Virus-Specific Responses of Heterosigma akashiwo to Infection  

Microsoft Academic Search

We used flow cytometry to examine the process of cell death in the bloom-forming alga Heterosigma akashiwo during infection by a double-stranded DNA virus (OIs1) and a single-stranded RNA virus (H. akashiwo RNA virus (HaRNAV)). These viruses were isolated from the same geographic area and infect the same strain of H. akashiwo. By use of the live\\/dead stains fluorescein diacetate

Janice E. Lawrence; Corina P. D. Brussaard; Curtis A. Suttle

2006-01-01

109

Gene expression and hepatitis C virus infection  

PubMed Central

Hepatitis C virus (HCV) is a major cause of chronic liver disease, with about 170 million people infected worldwide. Up to 70% of patients will have persistent infection after inoculation, making this disease a significant cause of morbidity and mortality. The severity of disease varies widely, from asymptomatic chronic infection to cirrhosis and hepatocellular carcinoma. Since the discovery of HCV, the treatment of hepatitis C has considerably improved. Recently, combination of pegylated interferons with ribavirin gives a response rate of about 55%. Treatment is indicated in patients with moderate or severe fibrosis. The tolerability of combination treatment is relatively poor, with a frequent flu-like syndrome and an impaired quality of life. In addition to viral and environmental behavioural factors, host genetic diversity is believed to contribute to the spectrum of clinical outcomes in HCV infection. The sequencing of the human genome, together with the development of high-throughput technologies that measure the function of the genome, have afforded unique opportunities to develop profiles that can distinguish, identify and classify discrete subsets of disease, predict the disease outcome or predict the response to treatment. This paper reviews the published literature on gene expression associated with HCV infection (HCV infection, fibrosis progression), and also according to response to treatment.

Asselah, T; Bieche, I; Sabbagh, A; Bedossa, P; Moreau, R; Valla, D; Vidaud, M; Marcellin, P

2009-01-01

110

Hepatitis C virus infection and insulin resistance  

PubMed Central

Approximately 170 million people worldwide are chronically infected with hepatitis C virus (HCV). Chronic HCV infection is the leading cause for the development of liver fibrosis, cirrhosis, hepatocellular carcinoma (HCC) and is the primary cause for liver transplantation in the western world. Insulin resistance is one of the pathological features in patients with HCV infection and often leads to development of type II diabetes. Insulin resistance plays an important role in the development of various complications associated with HCV infection. Recent evidence indicates that HCV associated insulin resistance may result in hepatic fibrosis, steatosis, HCC and resistance to anti-viral treatment. Thus, HCV associated insulin resistance is a therapeutic target at any stage of HCV infection. HCV modulates normal cellular gene expression and interferes with the insulin signaling pathway. Various mechanisms have been proposed in regard to HCV mediated insulin resistance, involving up regulation of inflammatory cytokines, like tumor necrosis factor-?, phosphorylation of insulin-receptor substrate-1, Akt, up-regulation of gluconeogenic genes like glucose 6 phosphatase, phosphoenolpyruvate carboxykinase 2, and accumulation of lipid droplets. In this review, we summarize the available information on how HCV infection interferes with insulin signaling pathways resulting in insulin resistance.

Bose, Sandip K; Ray, Ranjit

2014-01-01

111

Reference gene selection for quantitative real-time PCR analysis in virus infected cells: SARS corona virus, Yellow fever virus, Human Herpesvirus6, Camelpox virus and Cytomegalovirus infections  

Microsoft Academic Search

Ten potential reference genes were compared for their use in experiments investigating cellular mRNA expression of virus infected cells. Human cell lines were infected with Cytomegalovirus, Human Herpesvirus-6, Camelpox virus, SARS coronavirus or Yellow fever virus. The expression levels of these genes and the viral replication were determined by real-time PCR. Genes were ranked by the BestKeeper tool, the GeNorm

Aleksandar Radoni?; Stefanie Thulke; Hi-Gung Bae; Marcel A Müller; Wolfgang Siegert; Andreas Nitsche

2005-01-01

112

Immunological alterations in hepatitis C virus infection  

PubMed Central

A higher prevalence of immunological processes has recently been reported in patients with hepatitis C virus (HCV) infection, focusing the attention of physicians and researchers on the close association between HCV and immune disorders. HCV lymphotropism represents the most important step in the pathogenesis of virus-related immunological diseases and experimental, virologic, and clinical evidence has demonstrated a trigger role for HCV both in systemic autoimmune diseases, such as rheumatoid arthritis, Sjögren syndrome, hemolytic anemia and severe thrombocytopenia, and in organ-specific autoimmune diseases, such as autoimmune hepatitis, thyroid disorders and diabetes. This review will outline the principal aspects of such HCV-induced immunological alterations, focusing on the prevalence of these less characterized HCV extrahepatic manifestations.

Calvaruso, Vincenza; Craxi, Antonio

2013-01-01

113

Plant RNA binding proteins for control of RNA virus infection  

PubMed Central

Plant RNA viruses have effective strategies to infect host plants through either direct or indirect interactions with various host proteins, thus suppressing the host immune system. When plant RNA viruses enter host cells exposed RNAs of viruses are recognized by the host immune system through processes such as siRNA-dependent silencing. Interestingly, some host RNA binding proteins have been involved in the inhibition of RNA virus replication, movement, and translation through RNA-specific binding. Host plants intensively use RNA binding proteins for defense against viral infections in nature. In this mini review, we will summarize the function of some host RNA binding proteins which act in a sequence-specific binding manner to the infecting virus RNA. It is important to understand how plants effectively suppress RNA virus infections via RNA binding proteins, and this defense system can be potentially developed as a synthetic virus defense strategy for use in crop engineering.

Huh, Sung Un; Paek, Kyung-Hee

2013-01-01

114

The ecology of viruses that infect eukaryotic algae.  

PubMed

Because viruses of eukaryotic algae are incredibly diverse, sweeping generalizations about their ecology are rare. These obligate parasites infect a range of algae and their diversity can be illustrated by considering that isolates range from small particles with ssRNA genomes to much larger particles with 560?kb dsDNA genomes. Molecular research has also provided clues about the extent of their diversity especially considering that genetic signatures of algal viruses in the environment rarely match cultivated viruses. One general concept in algal virus ecology that has emerged is that algal viruses are very host specific and most infect only certain strains of their hosts; with the exception of viruses of brown algae, evidence for interspecies infectivity is lacking. Although some host-virus systems behave with boom-bust oscillations, complex patterns of intraspecies infectivity can lead to host-virus coexistence obfuscating the role of viruses in host population dynamics. Within the framework of population dynamics, host density dependence is an important phenomenon that influences virus abundances in nature. Variable burst sizes of different viruses also influence their abundances and permit speculations about different life strategies, but as exceptions are common in algal virus ecology, life strategy generalizations may not be broadly applicable. Gaps in knowledge of virus seasonality and persistence are beginning to close and investigations of environmental reservoirs and virus resilience may answer questions about virus inter-annual recurrences. Studies of algal mortality have shown that viruses are often important agents of mortality reinforcing notions about their ecological relevance, while observations of the surprising ways viruses interact with their hosts highlight the immaturity of our understanding. Considering that just two decades ago algal viruses were hardly acknowledged, recent progress affords the optimistic perspective that future studies will provide keys to unlocking our understanding of algal virus ecology specifically, and aquatic ecosystems generally. PMID:22360532

Short, Steven M

2012-09-01

115

Clustering of Giant Virus-DNA Based on Variations in Local Entropy  

PubMed Central

We present a method for clustering genomic sequences based on variations in local entropy. We have analyzed the distributions of the block entropies of viruses and plant genomes. A distinct pattern for viruses and plant genomes is observed. These distributions, which describe the local entropic variability of the genomes, are used for clustering the genomes based on the Jensen-Shannon (JS) distances. The analysis of the JS distances between all genomes that infect the chlorella algae shows the host specificity of the viruses. We illustrate the efficacy of this entropy-based clustering technique by the segregation of plant and virus genomes into separate bins.

Bose, Ranjan; Thiel, Gerhard; Hamacher, Kay

2014-01-01

116

Clustering of Giant Virus-DNA Based on Variations in Local Entropy.  

PubMed

We present a method for clustering genomic sequences based on variations in local entropy. We have analyzed the distributions of the block entropies of viruses and plant genomes. A distinct pattern for viruses and plant genomes is observed. These distributions, which describe the local entropic variability of the genomes, are used for clustering the genomes based on the Jensen-Shannon (JS) distances. The analysis of the JS distances between all genomes that infect the chlorella algae shows the host specificity of the viruses. We illustrate the efficacy of this entropy-based clustering technique by the segregation of plant and virus genomes into separate bins. PMID:24887142

Bose, Ranjan; Thiel, Gerhard; Hamacher, Kay

2014-01-01

117

Silymarin for hepatitis C virus infection  

PubMed Central

Silymarin, an extract of milk thistle seeds, and silymarin-derived compounds have been considered hepatoprotective since the plant was first described in ancient times. Hepatoprotection is defined as several non-mutually exclusive biological activities including antiviral, antioxidant, anti-inflammatory and immunomodulatory functions. Despite clear evidence for silymarin-induced hepatoprotection in cell culture and animal models, evidence for beneficial effects in humans has been equivocal. This review will summarize the current state of knowledge on silymarin in the context of hepatitis C virus infection. The information was collated from a recent workshop on silibinin in Germany.

Polyak, Stephen J; Oberlies, Nicholas H; Pecheur, Eve-Isabelle; Dahari, Harel; Ferenci, Peter; Pawlotsky, Jean-Michel

2014-01-01

118

Short-Lived Infected Cells Support Virus Replication in Sooty Mangabeys Naturally Infected with Simian Immunodeficiency Virus: Implications for AIDS Pathogenesis  

Microsoft Academic Search

Sooty mangabeys (SMs) naturally infected with simian immunodeficiency virus (SIV) do not develop AIDS despite high levels of virus replication. At present, the mechanisms underlying this disease resistance are poorly understood. Here we tested the hypothesis that SIV-infected SMs avoid immunodeficiency as a result of virus replication occurring in infected cells that live significantly longer than human immunodeficiency virus (HIV)-infected

Shari N. Gordon; Richard M. Dunham; Jessica C. Engram; Jacob Estes; Zichun Wang; Nichole R. Klatt; Mirko Paiardini; Ivona V. Pandrea; Cristian Apetrei; Donald L. Sodora; Ha Youn Lee; Ashley T. Haase; Michael D. Miller; Amitinder Kaur; Silvija I. Staprans; Alan S. Perelson; Mark B. Feinberg; Guido Silvestri

2008-01-01

119

Dynamics of perinatal bovine leukemia virus infection  

PubMed Central

Background Bovine leukemia virus (BLV) is highly endemic in many countries, including Argentina. As prevention of the spread from infected animals is of primary importance in breaking the cycle of BLV transmission, it is important to know the pathophysiology of BLV infection in young animals, as they are the main source of animal movement. In this work, we determined the proviral load and antibody titers of infected newborn calves from birth to first parturition (36 months). Results All calves under study were born to infected dams with high proviral load (PVL) in blood and high antibody titers and detectable provirus in the colostrum. The PVL for five out of seven calves was low at birth. All animals reached PVLs of more than 1% infected peripheral blood mononuclear cells (PBMCs), three at 3 months, one at 6 months, and one at 12 months. High PVLs persisted until the end of the study, and, in two animals, exceeded one BLV copy per cell. Two other calves maintained a high PVL from birth until the end of the study. Antibody titers were 32 or higher in the first sample from six out of seven calves. These decayed at 3–6 months to 16 or lower, and then increased again after this point. Conclusions Calves infected during the first week of life could play an active role in early propagation of BLV to susceptible animals, since their PVL raised up during the first 12 months and persist as high for years. Early elimination could help to prevent transmission to young susceptible animals and to their own offspring. To our knowledge, this is the first study of the kinetics of BLV proviral load and antibody titers in newborn infected calves.

2014-01-01

120

Dengue2 virus infection of human mononuclear cell lines and establishment of persistent infections  

Microsoft Academic Search

Summary Twenty three human mononuclear cell lines including ten myelomonocytic cell lines, eight B cell lines and five T cell lines, were examined to determine whether they could be infected with dengue-2 virus. All the cell lines were infected with dengue-2 virus as determined by immunofluorescent staining and by virus titration of culture supernatant fluids. K 562, Jiyoye and Jurkat,

I. Kurane; U. Kontny; J. Janus; F. A. Ennis

1990-01-01

121

Simultaneous multiplex PCR detection of seven cucurbit-infecting viruses.  

PubMed

Two multiplex polymerase chain reaction (PCR) systems using dual priming oligonucleotide (DPO) primers were developed for the simultaneous detection of seven cucurbit-infecting viruses. One system allows for the detection of papaya ringspot virus, watermelon mosaic virus, and zucchini yellow mosaic virus, whereas the other permits the detection of cucumber green mottle mosaic virus, cucumber fruit mottle mosaic virus, kyuri green mottle mosaic virus, and zucchini green mottle mosaic virus. Viral species-specific DPO primers developed in this study detected as little as 10fg/?l of viral RNA under monoplex conditions and 10pg/?l of viral RNA under multiplex conditions. Multiplex PCR using the DPO primer sets was capable of amplifying viral genes at annealing temperatures ranging from 53°C to 63°C. Whereas the use of conventional primers gave rise to non-specific bands, the DPO primers detected target viral genes in the absence of non-specific amplification. When these DPO multiplex primer sets were applied to virus-infected cucurbit samples obtained in the field, multiple infection as well as single infection was accurately identified. This novel approach could also detect multiple viruses in infected seeds. The reliability of multiplex PCR systems using DPO primers for plant virus detection is discussed. PMID:24937806

Kwon, Ji Yeon; Hong, Jin Sung; Kim, Min Jea; Choi, Sun Hee; Min, Byeong Eun; Song, Eun Gyeong; Kim, Hyun Hee; Ryu, Ki Hyun

2014-09-01

122

Peptide inhibitors against dengue virus infection.  

PubMed

Dengue virus (DENV) infection has become a public health problem worldwide. The development of anti-DENV drug is urgently needed because neither licensed vaccine nor specific drug is currently available. Inhibition of DENV attachment and entry to host cells by blocking DENV envelope (E) protein is an attractive strategy for anti-DENV drug development. A hydrophobic pocket on the DENV E protein is essential for structural transition in the membrane fusion, and inhibition of this process is able to inhibit DENV infection. To search for a safe anti-DENV drug, we identified short peptides targeting the hydrophobic pocket by molecular docking. In addition, the information of predicted ligand-binding site of reported active compounds of DENV2 hydrophobic pocket was also used for peptide inhibitors selection. The di-peptide, EF, was the most effective on DENV2 infection inhibition in vitro with a half maximal inhibition concentration (IC50) of 96 ?m. Treatment of DENV2 with EF at the concentration of 200 ?m resulted in 83.47% and 84.15% reduction in viral genome and intracellular E protein, respectively. Among four DENV serotypes, DENV2 was the most effective for the inhibition. Our results provide the proof of concept for the development of therapeutic peptide inhibitors against DENV infection by the computer-aided molecular design. PMID:24612829

Panya, Aussara; Bangphoomi, Kunan; Choowongkomon, Kiattawee; Yenchitsomanus, Pa-Thai

2014-08-01

123

ENHANCED AND PROLONGED PULMONARY INFLUENZA VIRUS INFECTION FOLLOWING PHOSGENE INHALATION  

EPA Science Inventory

Animal infectivity models have been important in the demonstration of enhanced susceptibility to viral and bacterial infection as a result of low level toxicant exposure. his study demonstrated an enhanced and prolonged viral infection using an influenza virus infectivity model i...

124

Evidence that hepatitis C virus genome partly controls infection outcome  

PubMed Central

Infection by hepatitis C virus (HCV) leads to one of two outcomes; either the infection resolves within approximately 6 months or the virus can persist indefinitely. Host genetics are known to affect the likelihood of clearance or persistence. By contrast, the importance of the virus genotype in determining infection outcome is unknown, as quantifying this effect traditionally requires well-characterized transmission networks, which are rare. Extending phylogenetic approaches previously developed to estimate the virus control over set-point viral load in HIV-1 infections, we simulate inheritance of a binary trait along a phylogenetic tree, use this data to quantify how infection outcomes cluster and ascertain the effect of virus genotype on these. We apply our method to the Hepatitis C Incidence and Transmission Study in prisons (HITS-p) data set from Australia, as this cohort prospectively identified incident cases including viraemic subjects who ultimately clear the virus, thus providing us with a unique collection of sequences from clearing infections. We detect significant correlations between infection outcome and virus distance in the phylogeny for viruses of Genotype 1, with estimates lying at around 67%. No statistically significant estimates were obtained for viruses of Genotype 3a.

Hartfield, Matthew; Bull, Rowena; White, Peter A; Lloyd, Andrew; Luciani, Fabio; Alizon, Samuel

2014-01-01

125

Evidence that hepatitis C virus genome partly controls infection outcome.  

PubMed

Infection by hepatitis C virus (HCV) leads to one of two outcomes; either the infection resolves within approximately 6 months or the virus can persist indefinitely. Host genetics are known to affect the likelihood of clearance or persistence. By contrast, the importance of the virus genotype in determining infection outcome is unknown, as quantifying this effect traditionally requires well-characterized transmission networks, which are rare. Extending phylogenetic approaches previously developed to estimate the virus control over set-point viral load in HIV-1 infections, we simulate inheritance of a binary trait along a phylogenetic tree, use this data to quantify how infection outcomes cluster and ascertain the effect of virus genotype on these. We apply our method to the Hepatitis C Incidence and Transmission Study in prisons (HITS-p) data set from Australia, as this cohort prospectively identified incident cases including viraemic subjects who ultimately clear the virus, thus providing us with a unique collection of sequences from clearing infections. We detect significant correlations between infection outcome and virus distance in the phylogeny for viruses of Genotype 1, with estimates lying at around 67%. No statistically significant estimates were obtained for viruses of Genotype 3a. PMID:24944567

Hartfield, Matthew; Bull, Rowena; White, Peter A; Lloyd, Andrew; Luciani, Fabio; Alizon, Samuel

2014-05-01

126

Oral manifestations of hepatitis C virus infection  

PubMed Central

Extrahepatic manifestations (EHMs) of hepatitis C virus (HCV) infection can affect a variety of organ systems with significant morbidity and mortality. Some of the most frequently reported EHM of HCV infection, involve the oral region predominantly or exclusively. Oral lichen planus (OLP) is a chronic inflammatory condition that is potentially malignant and represents cell-mediated reaction to a variety of extrinsic antigens, altered self-antigens, or super antigens. Robust epidemiological evidence support the link between OLP and HCV. As the virus may replicate in the oral mucosa and attract HCV-specific T lymphocytes, HCV may be implicated in OLP pathogenesis. Sjögren syndrome (SjS) is an autoimmune exocrinopathy, characterized by dryness of the mouth and eyes and a multitude of other systemic signs and symptoms. SjS patients have also an increased risk of non-Hodgkin lymphoma. Patients with chronic hepatitis C do frequently have histological signs of Sjögren-like sialadenitis with mild or even absent clinical symptoms. However, it is still unclear if HCV may cause a disease mimicking SjS or it is directly responsible for the development of SjS in a specific subset of patients. Oral squamous cell carcinoma is the most common oral malignant tumour and at least in some part of the world could be linked to HCV.

Carrozzo, Marco; Scally, Kara

2014-01-01

127

West nile virus infection of adult mice by oral route  

Microsoft Academic Search

Summary Adult Swiss albino mice were fed orally with suspensions of a strain of West Nile virus isolated in Nigeria. Most of these mice became sick and died 7 days post feeding and virus was recovered from organs of such infected mice. Histological lesions were observed in some tissues and antibody to the strain of West Nile virus developed in

H. A. Odelola; O. O. Oduye

1977-01-01

128

Some human dimensions of computer virus creation and infection  

Microsoft Academic Search

Infection of computer systems by destructive computer viruses is a commonplace occurrence. Consequently, an extensive literature exists concerning the technical means of virus prevention, detection and disinfection. By contrast, in this paper we consider the human dimensions and implications behind the invention and release of computer viruses. We examine and discuss some possible conscious motivations: these include political, commercial and

Andy Bissett; Geraldine Shipton

2000-01-01

129

Subclinical Infections with Crimean-Congo Hemorrhagic Fever Virus, Turkey  

PubMed Central

To investigate Crimean-Congo hemorrhagic fever virus in Turkey, we conducted a seroepidemiologic survey during January–April 2009. Seroprevalence of infection was 10% in a sample from an outbreak region and increased with patient age, indicating that the virus had been previously present in Turkey. We also estimated that 88% of infections were subclinical.

Akinci, Esragul; Ascioglu, Sibel; Onguru, Pinar; Uyar, Yavuz

2012-01-01

130

Immunofluorescence for routine diagnosis of respiratory syncytial virus infection  

Microsoft Academic Search

A comparison of immunofluorescent tests for the diagnosis of respiratory syncytial (RS) virus infections was carried out on 42 hospitalized cases of respiratory infection in childhood. Respiratory syncytial virus was detected in 22 (52%) cases, the most sensitive method of detection being by indirect immunofluorescence of Bristol HeLa tissue cultures inoculated with nasopharyngeal aspirates. The highest detection rate was in

G. E. D. Urquhart; G. H. Walker

1972-01-01

131

Renal involvement in children with influenza A virus infection  

Microsoft Academic Search

Renal involvement in influenza A virus infection has been rarely reported. To define the clinical characteristics and the factors contributing to the development of renal involvement in influenza A virus infection, we reviewed the clinical characteristics, laboratory data, pediatric risk of mortality (PRISM) score, and the number of systemic inflammatory response syndrome (SIRS) criteria and dysfunctional organs in 45 hospitalized

Toru Watanabe; Hideto Yoshikawa; Yuki Abe; Sawako Yamazaki; Yumiko Uehara; Tokinari Abe

2003-01-01

132

Immunomodulatory Activity of Red Ginseng against Influenza A Virus Infection  

PubMed Central

Ginseng herbal medicine has been known to have beneficial effects on improving human health. We investigated whether red ginseng extract (RGE) has preventive effects on influenza A virus infection in vivo and in vitro. RGE was found to improve survival of human lung epithelial cells upon influenza virus infection. Also, RGE treatment reduced the expression of pro-inflammatory genes (IL-6, IL-8) probably in part through interference with the formation of reactive oxygen species by influenza A virus infection. Long-term oral administration of mice with RGE showed multiple immunomodulatory effects such as stimulating antiviral cytokine IFN-? production after influenza A virus infection. In addition, RGE administration in mice inhibited the infiltration of inflammatory cells into the bronchial lumens. Therefore, RGE might have the potential beneficial effects on preventing influenza A virus infections via its multiple immunomodulatory functions.

Lee, Jong Seok; Hwang, Hye Suk; Ko, Eun-Ju; Lee, Yu-Na; Kwon, Young-Man; Kim, Min-Chul; Kang, Sang-Moo

2014-01-01

133

Infection with a plant virus modifies vector feeding behavior.  

PubMed

Vector infection by some animal-infecting parasites results in altered feeding that enhances transmission. Modification of vector behavior is of broad adaptive significance, as parasite fitness relies on passage to a new host, and vector feeding is nearly always essential for transmission. Although several plant viruses infect their insect vectors, we have shown that vector infection by a plant virus alters feeding behavior. Here we show that infection with Tomato spotted wilt virus (TSWV), type member of the only plant-infecting genus in the Bunyaviridae, alters the feeding behavior of its thrips vector, Frankliniella occidentalis (Pergande). Male thrips infected with TSWV fed more than uninfected males, with the frequency of all feeding behaviors increasing by up to threefold, thus increasing the probability of virus inoculation. Importantly, infected males made almost three times more noningestion probes (probes in which they salivate, but leave cells largely undamaged) compared with uninfected males. A functional cell is requisite for TSWV infection and cell-to-cell movement; thus, this behavior is most likely to establish virus infection. Some animal-infecting members of the Bunyaviridae (La Crosse virus and Rift Valley fever virus) also cause increased biting rates in infected vectors. Concomitantly, these data support the hypothesis that capacity to modify vector feeding behavior is a conserved trait among plant- and animal-infecting members of the Bunyaviridae that evolved as a mechanism to enhance virus transmission. Our results underscore the evolutionary importance of vector behavioral modification to diverse parasites with host ranges spanning both plant and animal kingdoms. PMID:21606372

Stafford, Candice A; Walker, Gregory P; Ullman, Diane E

2011-06-01

134

Giant viruses coexisted with the cellular ancestors and represent a distinct supergroup along with superkingdoms Archaea, Bacteria and Eukarya  

PubMed Central

Background The discovery of giant viruses with genome and physical size comparable to cellular organisms, remnants of protein translation machinery and virus-specific parasites (virophages) have raised intriguing questions about their origin. Evidence advocates for their inclusion into global phylogenomic studies and their consideration as a distinct and ancient form of life. Results Here we reconstruct phylogenies describing the evolution of proteomes and protein domain structures of cellular organisms and double-stranded DNA viruses with medium-to-very-large proteomes (giant viruses). Trees of proteomes define viruses as a ‘fourth supergroup’ along with superkingdoms Archaea, Bacteria, and Eukarya. Trees of domains indicate they have evolved via massive and primordial reductive evolutionary processes. The distribution of domain structures suggests giant viruses harbor a significant number of protein domains including those with no cellular representation. The genomic and structural diversity embedded in the viral proteomes is comparable to the cellular proteomes of organisms with parasitic lifestyles. Since viral domains are widespread among cellular species, we propose that viruses mediate gene transfer between cells and crucially enhance biodiversity. Conclusions Results call for a change in the way viruses are perceived. They likely represent a distinct form of life that either predated or coexisted with the last universal common ancestor (LUCA) and constitute a very crucial part of our planet’s biosphere.

2012-01-01

135

Dynamics of Persistent TT Virus Infection, as Determined in Patients Treated with Alpha Interferon for Concomitant Hepatitis C Virus Infection  

Microsoft Academic Search

TT virus (TTV) is a recently identified widespread DNA virus of humans that produces persistent viremia in the absence of overt clinical manifestations. In an attempt to shed light on the dynamics of chronic infection, we measured the levels of TTV in the plasma of 25 persistently infected patients during the first 3 months of alpha interferon (IFN-) treatment for

FABRIZIO MAGGI; MAURO PISTELLO; MARIALINDA VATTERONI; SILVANO PRESCIUTTINI; SANTINO MARCHI; PATRIZIA ISOLA; CLAUDIA FORNAI; SABINA FAGNANI; ELISABETTA ANDREOLI; GUIDO ANTONELLI; MAURO BENDINELLI

2001-01-01

136

Development of a candidate vaccine against Ross River virus infection.  

PubMed

Ross River virus is a mosquito-borne alphavirus which causes several thousand cases of arthritis (epidemic polyarthritis) each year. In this study, binary ethylenimine (BEI) was used to destroy the infectivity of this virus without abolishing the antigenicity or immunogenicity of the virion. Mice immunized intramuscularly with BEI-inactivated virus, with or without Alhydrogel adjuvant, produced antibody which neutralized Ross River virus in vitro, and the mice also failed to develop viraemia when challenged intravenously with live virus. Serum neutralization and in vivo protection were greatest when BEI-inactivated virus was administered without adjuvant. PMID:7998422

Yu, S; Aaskov, J G

1994-09-01

137

Hepatitis B virus infection and intrahepatic cholangiocarcinoma  

PubMed Central

Intrahepatic cholangiocarcinoma (ICC) is a devastating malignant tumor arising from the peripheral intrahepatic bile duct epithelium. The incidence and mortality of ICC is markedly increasing over the past two decades worldwide, though the cause for this rise in incidence is unclear, thus intensifying the search for alternative etiological agents and pathogenetic mechanisms. Hepatolithiasis, primary sclerosing cholangitis, parasitic infection (Opisthorchis viverrini or Clonorchis sinensis), fibropolycystic liver disease, and chemical carcinogen exposure are thought to be the risk factors for ICC. Nevertheless, the majority of ICC patients do not have any of these risk factors, and none of the established risk factors can explain the recent increasing trend of ICC. Therefore, identifying other risk factors may lead to the prevention and early detection of ICC. Chronic hepatitis B virus (HBV) infection is the predominant cause of hepatocellular carcinoma in HBV-endemic areas. This review discusses the evidence implicating chronic HBV infection as a likely etiology of ICC and the pathogenetic mechanisms that might be involved.

Zhou, Hua-Bang; Hu, Jing-Yi; Hu, He-Ping

2014-01-01

138

Effect of Human Immunodeficiency Virus on Hepatitis B Virus Serologic Status in Co-Infected Adults.  

National Technical Information Service (NTIS)

Background: Factors associated with serologic hepatitis B virus (HBV) outcomes in HIV-infected individuals remain incompletely understood, yet such knowledge may lead to improvements in the prevention and treatment of chronic HBV infection. Methods and Fi...

A. M. Fieberg H. M. Chun M. L. Landrum N. F. Crum- Cianflone V. C. Marconi

2010-01-01

139

Infection of lymphocytes by a virus that aborts cytotoxic T lymphocyte activity and establishes persistent infection  

PubMed Central

For viruses to establish persistent infections in their hosts, they must possess some mechanism for evading clearance by the immune system. When inoculated into adult immunocompetent mice, wild-type lymphocytic choriomeningitis virus (LCMV ARM) induces a CD8(+)-mediated cytotoxic T lymphocyte (CTL) response that clears the infection within 7-14 d (CTL+ [P-]). By contrast, variant viruses isolated from lymphoid tissues of persistently infected mice fail to induce a CTL response and are thus able to establish a persistent infection in adult mice (CTL- [P+]). This report compares the interaction of CTL+ (P-) and CTL- (P+) viruses with cells of the immune system. Both types of virus initially bind to 2-4% of CD4+ and CD8+ T lymphocytes and replicate within cells of both subsets. The replication of CTL- (P+) and CTL+ (P-) viruses in lymphocytes in vivo is similar for the first 5 d after initiating infection. Thereafter, in mice infected with CTL- (P+) variants, lymphocytes retain viral genetic information, and infectious virus can be recovered throughout the animals' lives. In contrast, when adult mice are infected with wild-type CTL+ (P-) LCMV ARM, virus is not recovered from lymphocytes for greater than 7 d after infection. A CD8(+)-mediated anti-LCMV CTL response is induced in such mice. Clearance of infected lymphocytes is produced by these LCMV-specific CTLs, as shown by their ability to lyse lymphocytes expressing LCMV determinants in vitro and the fact that depletion of CD8+ lymphocytes before infection with CTL+ (P-) viruses results in levels of infected lymphocytes similar to those found in undepleted CTL- (P+)-infected mice. Hence, CTL-mediated lysis of T lymphocytes carrying infectious virus is a critical factor determining whether virus persists or the infection is terminated.

1991-01-01

140

Limited hepatitis B virus replication space in the chronically hepatitis C virus-infected liver.  

PubMed

We compared the kinetics and magnitude of hepatitis B virus (HBV) infection in hepatitis C virus (HCV)-naive and chronically HCV-infected chimpanzees in whose livers type I interferon-stimulated gene (ISG) expression is strongly induced. HBV infection was delayed and attenuated in the HCV-infected animals, and the number of HBV-infected hepatocytes was drastically reduced. These results suggest that establishment of HBV infection and its replication space is limited by the antiviral effects of type I interferon in the chronically HCV-infected liver. PMID:24522924

Wieland, S F; Asabe, S; Engle, R E; Purcell, R H; Chisari, F V

2014-05-01

141

Unfolded protein response in hepatitis C virus infection  

PubMed Central

Hepatitis C virus (HCV) is a single-stranded, positive-sense RNA virus of clinical importance. The virus establishes a chronic infection and can progress from chronic hepatitis, steatosis to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). The mechanisms of viral persistence and pathogenesis are poorly understood. Recently the unfolded protein response (UPR), a cellular homeostatic response to endoplasmic reticulum (ER) stress, has emerged to be a major contributing factor in many human diseases. It is also evident that viruses interact with the host UPR in many different ways and the outcome could be pro-viral, anti-viral or pathogenic, depending on the particular type of infection. Here we present evidence for the elicitation of chronic ER stress in HCV infection. We analyze the UPR signaling pathways involved in HCV infection, the various levels of UPR regulation by different viral proteins and finally, we propose several mechanisms by which the virus provokes the UPR.

Chan, Shiu-Wan

2014-01-01

142

Frog virus 3-like infections in aquatic amphibian communities.  

PubMed

Frog virus 3 (FV3) and FV3-like viruses, are members of the genus Ranavirus (family Iridoviridae), and they have been associated with infectious diseases that may be contributing to amphibian population declines. We examined the mode of transmission of an FV3-like virus, and potential hosts and reservoirs of the virus in a local amphibian community. Using the polymerase chain reaction to detect infected animals, we found an FV3-like virus in south-central Ontario, Canada, amphibian communities, where it infects sympatric amphibian species, including ranid and hylid tadpoles (Rana sylvatica, Hyla versicolor, and Pseudacris spp.), larval salamanders (Ambystoma spp.), and adult eastern-spotted newts (Notophthalmus viridescens). The high prevalence of FV3-like infections in caudate larvae suggests that salamanders are likely to be both hosts and reservoirs. In laboratory FV3 challenges of R. sylvatica, the rate of infection was dependent on the amount of virus to which the animals were exposed. In addition, although vertical transmission was suspected, horizontal transmission through exposure to infected pond water is the most likely route of infection in tadpoles. Based on our observations, a simple model of FV3/FV3-like virus transmission postulates that, in aquatic amphibian communities, transmission of the virus occurs between anuran and urodele species, with ambystomatid salamanders the most likely reservoir for the ranavirus in our study. PMID:18263826

Duffus, A L J; Pauli, B D; Wozney, K; Brunetti, C R; Berrill, M

2008-01-01

143

Antibody dependent enhancement of frog virus 3 infection  

PubMed Central

Background Viruses included in the family Iridoviridae are large, icosahedral, dsDNA viruses that are subdivided into 5 genera. Frog virus 3 (FV3) is the type species of the genus Ranavirus and the best studied iridovirus at the molecular level. Typically, antibodies directed against a virus act to neutralize the virus and limit infection. Antibody dependent enhancement occurs when viral antibodies enhance infectivity of the virus rather than neutralize it. Results Here we show that anti-FV3 serum present at the time of FV3 infection enhances infectivity of the virus in two non-immune teleost cell lines. We found that antibody dependent enhancement of FV3 was dependent on the Fc portion of anti-FV3 antibodies but not related to complement. Furthermore, the presence of anti-FV3 serum during an FV3 infection in a non-immune mammalian cell line resulted in neutralization of the virus. Our results suggest that a cell surface receptor specific to teleost cell lines is responsible for the enhancement. Conclusions This report represents the first evidence of antibody dependent enhancement in iridoviruses. The data suggests that anti-FV3 serum can either neutralize or enhance viral infection and that enhancement is related to a novel antibody dependent enhancement pathway found in teleosts that is Fc dependent.

2010-01-01

144

Characterization of shrimp Drosha in virus infection.  

PubMed

RNA interference (RNAi) mediated by microRNA (miRNA) is an evolutionarily conserved mechanism of posttranscriptional gene regulation in all eukaryotes, involving in natural antiviral immunity. The RNAase III Drosha is a key component for miRNA maturation. To date, however, the roles of Drosha in virus infection remain to be addressed. In this study, the Drosha was characterized in Marsupenaeus japonicus shrimp. The sequence analysis revealed that the shrimp Drosha gene encoded a 1081-amino-acid peptide, which comprised two tandem ribonuclease III C terminal domains and a double-stranded RNA binding motif. The shrimp Drosha was homologous with those of other animal species. The quantitative RT-PCR analysis revealed that the Drosha gene was highly expressed in lymphoid organ and was significantly up-regulated in response to WSSV challenge, suggesting that the Drosha was involved in the antiviral immunity of shrimp. The results showed that the knock down of Drosha gene led to the defect of miRNA maturation, and subsequent higher virus loads in shrimp. Our study presented that Drosha played important roles in the antiviral defense of shrimp. PMID:22796424

Huang, Tianzhi; Xu, Dandan; Zhang, Xiaobo

2012-09-01

145

A Novel Single Virus Infection System Reveals That Influenza Virus Preferentially Infects Cells in G1 Phase  

PubMed Central

Background Influenza virus attaches to sialic acid residues on the surface of host cells via the hemagglutinin (HA), a glycoprotein expressed on the viral envelope, and enters into the cytoplasm by receptor-mediated endocytosis. The viral genome is released and transported in to the nucleus, where transcription and replication take place. However, cellular factors affecting the influenza virus infection such as the cell cycle remain uncharacterized. Methods/Results To resolve the influence of cell cycle on influenza virus infection, we performed a single-virus infection analysis using optical tweezers. Using this newly developed single-virus infection system, the fluorescence-labeled influenza virus was trapped on a microchip using a laser (1064 nm) at 0.6 W, transported, and released onto individual H292 human lung epithelial cells. Interestingly, the influenza virus attached selectively to cells in the G1-phase. To clarify the molecular differences between cells in G1- and S/G2/M-phase, we performed several physical and chemical assays. Results indicated that: 1) the membranes of cells in G1-phase contained greater amounts of sialic acids (glycoproteins) than the membranes of cells in S/G2/M-phase; 2) the membrane stiffness of cells in S/G2/M-phase is more rigid than those in G1-phase by measurement using optical tweezers; and 3) S/G2/M-phase cells contained higher content of Gb3, Gb4 and GlcCer than G1-phase cells by an assay for lipid composition. Conclusions A novel single-virus infection system was developed to characterize the difference in influenza virus susceptibility between G1- and S/G2/M-phase cells. Differences in virus binding specificity were associated with alterations in the lipid composition, sialic acid content, and membrane stiffness. This single-virus infection system will be useful for studying the infection mechanisms of other viruses.

Ueda, Ryuta; Sugiura, Tadao; Kume, Shinichiro; Ichikawa, Akihiko; Larsen, Steven; Miyoshi, Hideaki; Hiramatsu, Hiroaki; Nagatsuka, Yasuko; Arai, Fumihito; Suzuki, Yasuo; Hirabayashi, Yoshio; Fukuda, Toshio; Honda, Ayae

2013-01-01

146

Human T-cell lymphotropic virus type III infection of the central nervous system: a preliminary in situ analysis  

SciTech Connect

Patients with acquired immunodeficiency syndrome (AIDS) are subject to a spectrum of central nervous system (CNS) disorders. Recent evidence implicates the human T-cell lymphotropic virus type III (HTLV-III) in the pathogenesis of some of these illnesses, although the cells infected by the virus have yet to be identified. Using in situ hybridization, the authors examined brain tissue from two patients with AIDS encephalopathy for the presence of HTLV-III RNA. In both cases, viral RNA was detected and concentrated in, though not limited to, the white matter. The CNS cells most frequently infected included macrophages, pleomorphic microglia, and multinucleated giant cells. Less frequently, cells morphologically consistent with astrocytes, oligodendroglia, and rarely neurons were also infected. The findings strengthen the association of HTLV-III with the pathogenesis of AIDS encephalopathy. In situ hybridization can be applied to routinely prepared biopsy tissue in the diagnosis of HTLV-III infection of the CNS.

Stoler, M.H.; Eskin, T.A.; Benn, S.; Angerer, R.C.; Angerer, L.M.

1986-11-07

147

Effects of influenza A virus infection on migrating mallard ducks  

PubMed Central

The natural reservoir of influenza A virus is waterfowl, particularly dabbling ducks (genus Anas). Although it has long been assumed that waterfowl are asymptomatic carriers of the virus, a recent study found that low-pathogenic avian influenza (LPAI) infection in Bewick's swans (Cygnus columbianus bewickii) negatively affected stopover time, body mass and feeding behaviour. In the present study, we investigated whether LPAI infection incurred ecological or physiological costs to migratory mallards (Anas platyrhynchos) in terms of body mass loss and staging time, and whether such costs could influence the likelihood for long-distance dispersal of the avian influenza virus by individual ducks. During the autumn migrations of 2002–2007, we collected faecal samples (n=10?918) and biometric data from mallards captured and banded at Ottenby, a major staging site in a flyway connecting breeding and wintering areas of European waterfowl. Body mass was significantly lower in infected ducks than in uninfected ducks (mean difference almost 20?g over all groups), and the amount of virus shed by infected juveniles was negatively correlated with body mass. There was no general effect of infection on staging time, except for juveniles in September, in which birds that shed fewer viruses stayed shorter than birds that shed more viruses. LPAI infection did not affect speed or distance of subsequent migration. The data from recaptured individuals showed that the maximum duration of infection was on average 8.3 days (s.e. 0.5), with a mean minimum duration of virus shedding of only 3.1 days (s.e. 0.1). Shedding time decreased during the season, suggesting that mallards acquire transient immunity for LPAI infection. In conclusion, deteriorated body mass following infection was detected, but it remains to be seen whether this has more long-term fitness effects. The short virus shedding time suggests that individual mallards are less likely to spread the virus at continental or intercontinental scales.

Latorre-Margalef, Neus; Gunnarsson, Gunnar; Munster, Vincent J.; Fouchier, Ron A.M.; Osterhaus, Albert D.M.E.; Elmberg, Johan; Olsen, Bjorn; Wallensten, Anders; Haemig, Paul D.; Fransson, Thord; Brudin, Lars; Waldenstrom, Jonas

2008-01-01

148

Hepatitis C virus infection in the United States  

Microsoft Academic Search

Hepatitis C virus (HCV) infection is the most common chronic bloodborne infection in the United States, and most infected persons are younger than 50 years old. The relative importance of the two most common exposures associated with transmission of HCV, blood transfusion and intravenous drug use (IVDU), has changed over time. Blood transfusion, which accounted for a substantial proportion of

Miriam J. Alter

1999-01-01

149

Influenza and respiratory syncytial virus infections in British Hajj pilgrims  

Microsoft Academic Search

Viral respiratory infections including influenza and respiratory syncytial virus (RSV) have been reported during the Hajj among international pilgrims. To help establish the burden of these infections at the Hajj, we set up a study to confirm these diagnoses in symptomatic British pilgrims who attended the 2005 Hajj. UK pilgrims with symptoms of upper respiratory tract infection (URTI) were invited

H Rashid; S Shafi; R Booy; H El Bashir; K Ali; MC Zambon; ZA Memish; J Ellis; PG Coen; E Haworth

2008-01-01

150

Interferon gene transfer by a hepatitis B virus vector efficiently suppresses wild-type virus infection  

PubMed Central

Hepatitis B viruses specifically target the liver, where they efficiently infect quiescent hepatocytes. Here we show that human and avian hepatitis B viruses can be converted into vectors for liver-directed gene transfer. These vectors allow hepatocyte-specific expression of a green fluorescent protein in vitro and in vivo. Moreover, when used to transduce a type I interferon gene, expression of interferon efficiently suppresses wild-type virus replication in the duck model of hepatitis B virus infection. These data suggest local cytokine production after hepatitis-B-virus-mediated gene transfer as a promising concept for the treatment of acquired liver diseases, including chronic hepatitis B.

Protzer, Ulrike; Nassal, Michael; Chiang, Pei-Wen; Kirschfink, Michael; Schaller, Heinz

1999-01-01

151

Steroid-responsive, progressive, focal measles virus brain infection.  

PubMed

Chronic measles virus infection of the brain causes subacute sclerosing panencephalitis (SSPE), a progressive, relentless fatal disorder. We report a 52-year-old male who developed focal, chronic persistent measles virus infection of the brain following interferon and ribavirin therapy for hepatitis C, and who responded to steroid therapy. This case, diametrically different from SSPE, has 2 unique features, its focal nature and its permissive response to steroids, that may add to the understanding of the pathogenesis of SSPE and the mechanism enabling viruses to evade the immune response and establish persistent brain infection. Ann Neurol 2014;75:967-970. PMID:24817010

Steiner, Israel; Livneh, Vered; Hoffmann, Chen; Nass, Dvora; Mor, Orna; Chapman, Joab

2014-06-01

152

Method and medicament for inhibiting the infection of influenza virus  

US Patent & Trademark Office Database

The invention relates to a process for inhibiting the infection of influenza viruses and a polypeptide or protein medicine used therein. More particularly, the invention involves a process for inhibiting the highly pathogenic avian influenza virus (such as H5N1 subtype) infection and human influenza virus (such as H1N1 subtype and H3N2 subtype) infection, as well as the polypeptide or protein involved therein, and a polynucleotide encoding the polypeptide or protein and a vector or host cell expressing said polypeptide or protein.

2013-06-25

153

Molecular and clinical aspects of hepatitis D virus infections  

PubMed Central

Hepatitis D virus (HDV) is a defective virus with circular, single-stranded genomic RNA which needs hepatitis B virus (HBV) as a helper virus for virion assembly and infectivity. HDV virions are composed of a circular shape HDV RNA and two types of viral proteins, small and large HDAgs, surrounded by HBV surface antigen (HBsAg). The RNA polymerase II from infected hepatocytes is responsible for synthesizing RNAs with positive and negative polarities for HDV, as the virus does not code any enzyme to replicate its genome. HDV occurs as co-infection or super-infection in up to 5% of HBsAg carriers. A recent multi-center study highlighted that pegylated interferon ?-2a (PEG-IFN) is currently the only treatment option for delta hepatitis. Nucleotide/nucleoside analogues, which are effective against HBV, have no relevant effects on HDV. However, additional clinical trials combining PEG-IFN and tenofovir are currently ongoing. The molecular interactions between HDV and HBV are incompletely understood. Despite fluctuating patterns of HBV viral load in the presence of HDV in patients, several observations indicate that HDV has suppressive effects on HBV replication, and even in triple infections with HDV, HBV and HCV, replication of both concomitant viruses can be reduced. Additional molecular virology studies are warranted to clarify how HDV interacts with the helper virus and which key cellular pathways are used by both viruses. Further clinical trials are underway to optimize treatment strategies for delta hepatitis.

Dastgerdi, Elham Shirvani; Herbers, Ulf; Tacke, Frank

2012-01-01

154

Prevalence of Hepatitis Virus Infections in an Institution for Persons with Developmental Disabilities.  

ERIC Educational Resources Information Center

A study involving 1,235 residents of Sonoma Developmental Center found 3 residents had hepatitis C virus infections, and 633 had past or current hepatitis B virus infections. The prevalence of hepatitis B virus infection rose rapidly with longer residence in institutions. Hepatitis A virus infection had occurred in 494 residents. (Contains…

Woodruff, Bradley A.; Vazquez, Elizabeth

2002-01-01

155

Liver Enlargement Associated with Opportunistic Infections in Patients with Human Immunodeficiency Virus Infection  

Microsoft Academic Search

Background & Aim. Liver disease is commonly present in human immunodeficiency virus (HIV) infection. The aim was to determine the frequency of liver enlargement and its association with opportunistic infections in patients with HIV infection. Patients and methods. A total of 400 HIV-infected patients were investigated. Commercial kits (Ortho EIA; BioRad, ELISA) were used for detection of serum specific antibodies

Dragica Terzic; Branko Brmbolic; Djordje Jevtovic; Brankica Dupanovic; Milos Kora; Dubravka Selemovic; Neda Svirtlih; Nenad Draskovic; Boban Mugosa; Ivan Boricic; Zoran Terzic

156

Studies on Respiratory Syncytial Virus Infection in the Ferret.  

National Technical Information Service (NTIS)

Infant ferrets are protected from respiratory syncytial virus (RSV) replication by nursing on mothers rendered immune by a previous RSV infection. The protective substance appears to be IgG, but milk lipid carries an additional or synergistic neutralizing...

D. D. Porter S. C. Suffin

1978-01-01

157

Drug Targets in Infections With Ebola and Marburg Viruses.  

National Technical Information Service (NTIS)

The development of antiviral drugs for Ebola and Marburg viruses has been slow. To date, beyond supportive care, no effective treatments, prophylactic measures, therapies or vaccines are approved to treat or prevent filovirus infections. In this review, w...

B. E. Julia G. W. Thomas M. R. Vanessa O. G. Gene W. Victoria

2009-01-01

158

Aerosol Stability and Respiratory Infectivity of Lassa Virus.  

National Technical Information Service (NTIS)

*The aerosol stability and respiratory infectivity of Lassa virus were assessed. Aerosol stability determinations were performed at 24 C and each of three relative humidities (RH) (30, 55, and 80%). A highly significant difference existed between aerosol ...

E. W. Larson E. H. Stephenson J. W. Dominik

1982-01-01

159

Laboratory Diagnosis of Human Immuno Deficiency Virus Infection.  

National Technical Information Service (NTIS)

The acquired immune deficiency syndrome (AIDS) is the clinically apparent preterminal stage of the prolonged infection with the human immunodeficiency virus (HIV), most often manifested as Pneumocystis carinii pneumonia, Kaposi's sarcoma, or other opportu...

D. S. Burke

1989-01-01

160

Experimental Infection of Horses With West Nile virus  

Microsoft Academic Search

A total of 12 horses of different breeds and ages were infected with West Nile virus (WNV) via the bites of infected Aedes albopictus mosquitoes. Half the horses were infected with a viral isolate from the brain of a horse (BC787), and half were infected with an isolate from crow brain (NY99-6625); both were NY99 iso- lates. Postinfection, uninfected female

Michel L. Bunning; Richard A. Bowen; C. Bruce Cropp; Kevin G. Sullivan; Brent S. Davis; Nicholas Komar; Marvin S. Godsey; Dale Baker; Danielle L. Hettler; Derek A. Holmes; Brad J. Biggerstaff; Carl J. Mitchell

2002-01-01

161

Applied Aspects of Induced Resistance to Plant Virus Infection  

Microsoft Academic Search

Plant virus diseases occur worldwide in cultivated plant species as well as many native (weed) plants. A plant virus is dependent\\u000a on host and vector for its “survival”. The efficiency and extent of spread of infection within a plant are important factors\\u000a for allowing the virus to be accessible to its vector(s), which in turn allows for dispersal of the

John F. Murphy

162

Virus and Infections 2010 - BIT's first world congress.  

PubMed

The World Congress of Virus and Infections, held in Busan, South Korea, included topics reviewing the field of zoonoses. This conference report highlights selected presentations on surveillance, epidemiology and measures for the control and prevention of zoonotic diseases. Topics discussed include human factors influencing zoonoses, the molecular epidemiology of Crimean-Congo hemorrhagic fever, the emerging Nipah virus, and the re-emergence of cowpox virus. PMID:20878585

Garkavenko, Olga

2010-10-01

163

Influenza Virus Infection in Guinea Pigs Raised as Livestock, Ecuador  

PubMed Central

To determine whether guinea pigs are infected with influenza virus in nature, we conducted a serologic study in domestic guinea pigs in Ecuador. Detection of antibodies against influenza A and B raises the question about the role of guinea pigs in the ecology and epidemiology of influenza virus in the region.

Leyva-Grado, Victor H.; Mubareka, Samira; Krammer, Florian; Cardenas, Washington B.

2012-01-01

164

The specificity of Helicoverpa armigera stunt virus infectivity.  

PubMed

Helicoverpa armigera stunt virus (HaSV) is a member of the Tetraviridae family of RNA viruses whose replication and expression strategies are not well understood due to the absence of an in vitro cell culture system. We set out to find such a system for HaSV by screening an array of 13 insect and 1 mammalian cell culture lines with both virus particle infection and genomic RNA transfection. No cell line was found to be permissive for replication, although entry of genomic RNA was verified. The apparent specificity of this virus for its in vivo midgut target site was strongly corroborated by studies involving Northern blots of RNA extracted from infected insects. Only larval midgut RNA showed the presence of virus after hosts were infected per os or by injection which exposed other host cell types to the virus. The absence of replication in cell culture was due to a lack, or presence, of host factors important to replicase activity and also the likely absence of virus particle binding and entry. We thus provide both in vitro- and in vivo-based evidence demonstrating that this virus is extremely specific in the type of cells in which it will initiate an infection. PMID:10486228

Bawden, A L; Gordon, K H; Hanzlik, T N

1999-09-01

165

Jejunal enteropathy associated with human immunodeficiency virus infection: quantitative histology  

Microsoft Academic Search

Jejunal biopsy specimens from 20 human immunodeficiency virus (HIV) positive male homosexual patients were analysed and compared with those of a control group to determine whether the abnormalities were caused by the virus or by opportunistic infection. The degree of villous atrophy was estimated with a Weibel eyepiece graticule, and this correlated strongly with the degree of crypt hyperplasia, which

P A Batman; A R Miller; S M Forster; J R Harris; A J Pinching; G E Griffin

1989-01-01

166

Viral protein synthesis in cowpea mosaic virus-infected protoplasts  

Microsoft Academic Search

In contrast to the situation concerning bacterial and, to a lesser extent, animal RNA viruses, little is known about the biochemical processes occurring in plant cells due to plant RNA virus infection. Such processes are difficult to study using intact plants or leaves. Great effort has therefore been spent in developing in vitro cultures of plant protoplasts, but the use

P. J. M. Rottier

1980-01-01

167

First report of Chikungunya virus infection in Nepal.  

PubMed

Chikungunya virus is an emerging arboviral disease that has been spreading rapidly across south Asia in recent years. Until recently, no chikungunya cases have been reported in Nepal. For the first time, we report three cases of chikungunya virus infection in Nepal. PMID:24916880

Pun, Sher Bahadur; Bastola, Anup; Shah, Rajesh

2014-01-01

168

Release of Viral Glycoproteins during Ebola Virus Infection  

Microsoft Academic Search

Maturation and release of the Ebola virus glycoprotein GP were studied in cells infected with either Ebola or recombinant vaccinia viruses. Significant amounts of GP were found in the culture medium in nonvirion forms. The major form represented the large subunit GP1that was shed after release of its disulfide linkage to the smaller transmembrane subunit GP2. The minor form were

Viktor E. Volchkov; Valentina A. Volchkova; Werner Slenczka; Hans-Dieter Klenk; Heinz Feldmann

1998-01-01

169

Cell infection within a microfluidic device using virus gradients  

Microsoft Academic Search

A microfluidic device has been developed which allows cells to be infected at many different concentrations of virus within a microscale environment. Diffusion and laminar flow were used to create a concentration gradient of virus particles over cells attached to the bottom of a microchannel. The expression of green fluorescent protein (GFP) was monitored optically in situ over several days.

G. M. Walker; M. S. Ozers; D. J. Beebe

2004-01-01

170

Infection of Triticum monococcum Protoplasts with Barley Yellow Dwarf Virus  

Microsoft Academic Search

SUMMARY Protoplasts from a Triticum monococcum cell culture line were successfully infected with barley yellow dwarf virus. Both purified virions and extracted RNA were shown to be infectious using a polyethylene glycol inoculation procedure. Up to 209\\/00 of the protoplasts contained viral antigens as judged by immunofluorescence assay. ELISA analysis showed that virus antigen expression was both dose- and time-dependent.

M. J. Young; P. J. Larkin; W. A. Miller; P. M. Waterhouse; W. L. Gerlach

1989-01-01

171

Toscana Virus Central Nervous System Infections in Southern Italy  

Microsoft Academic Search

Toscana virus was detected by reverse transcription-nested PCR in 5.6% of cerebrospinal fluid (CSF) samples from patients with meningitis and encephalitis during the summer in southern Italy. The central nervous system infections were associated with young adults and with a substantially benign clinical course. Presenting features and CSF findings are also discussed in the present report. Toscana virus (TOSV) is

Pasquale Pagliano; Sonia Battisti; Maria Starace; Vera Mininni

172

The Human Immunodeficiency Virus: Infectivity and Mechanisms of Pathogenesis.  

ERIC Educational Resources Information Center

Discusses how the infection of the human immunodeficiency virus (HIV) results in a profound immunosuppression due predominantly to a selective depletion of helper/inducer T lymphocytes that express the receptor for the virus, as well as neuropsychiatric abnormalities in the brain. (TW)

Fauci, Anthony S.

1988-01-01

173

Limitations to tobacco mosaic virus infection of turnip  

Microsoft Academic Search

Summary.  ?Turnip vein-clearing virus (TVCV) and tobacco mosaic virus (TMV) represent subgroups of tobamoviruses infecting cruciferous\\u000a and solanaceous plants, respectively. To identify adaptations that may have been necessary in the evolution of the TVCV subgroup\\u000a from a TMV-like ancestor, the infection of turnip plants by TMV and by chimeras between TMV and TVCV was explored. TMV accumulated\\u000a at spatially limited sites

Y. Zhang; R. T. Lartey; S. D. Hartson; T. C. Voss; U. Melcher

1999-01-01

174

Lactoferrin inhibits hepatitis B virus infection in cultured human hepatocytes  

Microsoft Academic Search

We recently reported that lactoferrin (LF), a milk protein belonging to the iron transporter family, inhibits hepatitis C virus (HCV) infection in cultured human hepatocytes (PH5CH8) and that the interaction of LF with HCV is responsible for this inhibitory effect. As PH5CH8 cells were found to be a human hepatocyte line susceptible to hepatitis B virus (HBV) infection, we therefore

Koji Hara; Masanori Ikeda; Satoru Saito; Shuhei Matsumoto; Kazushi Numata; Nobuyuki Kato; Katsuaki Tanaka; Hisahiko Sekihara

2002-01-01

175

Cytokine production and signaling pathways in respiratory virus infection  

PubMed Central

It has been confirmed that respiratory virus infections can induce abberant cytokine production in the host. These cytokines may be associated with both elimination of the virus and complications in the host, such as virus-induced asthma. Representative host defense mechanisms against pathogens, including bacteria and viruses, are mediated by the innate immune system. Cells of the innate immune system express essential molecules, namely pattern recognition receptors (PRRs), such as Toll-like receptors, nucleotide-binding oligomerization domain-like receptors, and retinoic acid-inducible gene-I-like receptors. These PRRs can recognize components of pathogens such as bacterial lipopolysaccharide, viral antigens, and their genomes (DNA and RNA). Furthermore, PRRs activate various signaling pathways resulting in cytokine production against pathogen infection. However, the exact mechanisms remain unknown. In this review, we mainly focus on the representative mechanisms of cytokine production through PRRs and signaling pathways due to virus infections, including respiratory virus infections. In addition, we describe the relationships between respiratory infections and virus-induced asthma.

Kimura, Hirokazu; Yoshizumi, Masakazu; Ishii, Haruyuki; Oishi, Kazunori; Ryo, Akihide

2013-01-01

176

Hepatitis C Virus and HIV Type 1 Co-Infection.  

PubMed

Around 33 million people worldwide are living with Human Immunodeficiency Virus (HIV) infection, and approximately 20-30% of HIV-infected individuals are also infected with Hepatitis C virus (HCV). The main form of HCV transmission is via the blood borne route; high rates of co-infection are found in intravenous drug users with HCV prevalence rates as high as 90%. Introduction of effective antiretroviral therapy (ART) has led to a significant decline in HIV-related morbidity, but at the same time the incidence of HCV related liver disease is increasing in the co-infected population. Meta analysis has revealed that individuals who are co-infected with HIV/HCV harbor three times greater risk of progression to liver disease than those infected with HCV alone. Increased risk of progression to Acquired Immunodeficiency Syndrome (AIDS) and AIDS-related deaths is shown among the co-infected patients by some studies, suggesting that HCV infection may accelerate the clinical course of HIV infection. HCV may also affect the incidence of liver toxicity associated with ART, affecting the management of HIV infection. There is a lack of optimal therapeutic approaches to treat HCV infection in HIV co-infected patients. This review discusses recent literature pertaining HIV/HCV co-infection, in addition to providing a snapshot of impact of co-infection on human genome at the level of gene expression and its regulation by microRNAs (miRNAs). PMID:24470971

Gupta, Priyanka

2013-06-01

177

Germacrone inhibits early stages of influenza virus infection.  

PubMed

Highly pathogenic influenza viruses pose a serious public health threat to humans. Although vaccines are available, antivirals are needed to efficiently control disease progression and virus transmission due to the emergence of drug-resistant viral strains. In this study, germacrone, which is a major component of the essential oils extracted from Rhizoma Curcuma, was found to inhibit influenza virus replication. Germacrone showed antiviral activity against the H1N1 and H3N2 influenza A viruses and the influenza B virus in a dose-dependent manner. The viral protein expression, RNA synthesis and the production of infectious progeny viruses were decreased both in MDCK and A549 cells treated with germacrone. In a time-of-addition study, germacrone was found to exhibit an inhibitory effect on both the attachment/entry step and the early stages of the viral replication cycle. Germacrone also exhibited an effective protection of mice from lethal infection and reduced the virus titres in the lung. Furthermore, the combination of germacrone and oseltamivir exhibited an additive effect on the inhibition of influenza virus infection, both in vitro and in vivo. Our results suggest that germacrone may have the potential to be developed as a therapeutic agent alone or in combination with other agents for the treatment of influenza virus infection. PMID:24095670

Liao, Qingjiao; Qian, Zhengxu; Liu, Rui; An, Liwei; Chen, Xulin

2013-12-01

178

Effects of Clinacanthus siamensis leaf extract on influenza virus infection.  

PubMed

Ethanolic extracts of 20 medicinal plants were screened for influenza virus NA inhibition and in vitro antiviral activities using MDCK cells in an MTT assay. The vaccine proteins of influenza virus A/New Caledonia/20/99 (H1N1), mouse-adapted influenza virus A/Guizhou/54/89 (A/G)(H3N2) and mouse-adapted influenza virus B/Ibaraki/2/85 (B/I) were used in the NA inhibition assay, and mouse-adapted influenza viruses A/PR/8/34 (H1N1), A/G and B/I were used in the in vitro antiviral assay. The results of the in vitro antiviral assay indicated that the A/G virus was the most susceptible and an extract of the leaf of CS possessed the highest in vitro anti-A/G virus activity (41.98%). Therefore, the A/G virus and the CS extract were selected for studying in vivo anti-influenza virus activity. BALB/c mice were treated with CS extract (100 mg/kg per day, 5 times) orally from 4 hr before to 4 days after infection. CS extract elicited significant production of anti-influenza virus IgG(1) antibody in BAW and increased mouse weight compared to oseltamivir (0.1 mg/kg per day) on day 19 or water on days 17-19 of infection. Moreover, CS extract produced a higher anti-influenza virus IgA antibody level in BAW compared to oseltamivir, and a tendency towards an increase in anti-influenza virus IgA compared to water was shown. The results suggest that CS extract has a protective effect against influenza virus infection. PMID:19291089

Wirotesangthong, Mali; Nagai, Takayuki; Yamada, Haruki; Amnuoypol, Surattana; Mungmee, Chutichot

2009-02-01

179

Neonatal Herpes Virus Infection and Extracorporeal Life Support  

PubMed Central

Background Currently, scant data exists regarding ECMO support in neonates with herpes virus infection. Objectives We investigated outcomes among neonates with herpes virus infection reported to the Extracorporeal Life Support Organization (ELSO) registry and analyzed factors associated with death prior to hospital discharge with this virus. Design Retrospective analysis of ELSO registry dataset from 1985–2005. Setting 114 ECMO centers contributing data to the ELSO registry. Patients Patients 0–31 days of age with herpes simplex virus infection supported with ECMO and reported to the ELSO registry. Interventions None Methods Clinical characteristics, outcomes, and factors associated with death prior to hospital discharge were investigated for patients in the virus group. Kaplan-Meier estimates of survival to hospital discharge according to virus type were investigated. Measurements and Main Results Newborns with HSV infection requiring ECMO support demonstrated much lower hospital survival rates (25%). Clinical presentation with septicemia/ shock was significantly associated with mortality for the HSV group on multivariate analysis. There was no difference in HSV mortality when comparing two era’s (? 2000 versus < 2000). Conclusions In this cohort of neonatal patients with overwhelming infections due to HSV who were supported with ECMO, survival was dismal. Patients with disseminated HSV infection presenting with septicemia/ shock are unlikely to survive, even with aggressive extracorporeal support.

Prodhan, Parthak; Wilkes, Ryan; Ross, Ashley; Garcia, Xiomara; Bhutta, Adnan T; Rycus, Peter; Fiser, Richard T

2011-01-01

180

Respiratory syncytial virus: co-infection and paediatric lower respiratory tract infections.  

PubMed

Comprehensive population-based data on the role of respiratory viruses in the development of lower respiratory tract infections (LRTIs) remain unclear. We investigated the incidence and effect of single and multiple infections with respiratory viruses on the risk of LRTIs in Vietnam. Population-based prospective surveillance and a case-control study of hospitalised paediatric patients with acute respiratory infection (ARI) were conducted from April 2007 through to March 2010. Healthy controls were randomly recruited from the same community. Nasopharyngeal samples were collected and tested for 13 respiratory viruses using multiplex PCRs. 1992 hospitalised ARI episodes, including 397 (19.9%) with LRTIs, were enrolled. Incidence of hospitalised LRTIs among children aged <24 months was 2171.9 per 100 000 (95% CI 1947.9-2419.7). The majority of ARI cases (60.9%) were positive for at least one virus. Human rhinovirus (24.2%), respiratory syncytial virus (20.1%) and influenza A virus (12.0%) were the most common and 9.5% had multiple-viral infections. Respiratory syncytial virus and human metapneumovirus infections independently increased the risk of LRTIs. Respiratory syncytial virus further increased the risk, when co-infected with human rhinovirus, human metapneumovirus and parainfluenza virus-3 but not with influenza A virus. The case-control analysis revealed that respiratory syncytial virus and influenza A virus increased the risk of ARI hospitalisation but not human rhinovirus. Respiratory syncytial virus is the leading pathogen associated with risk of ARI hospitalisation and LRTIs in Vietnam. PMID:23645407

Yoshida, Lay-Myint; Suzuki, Motoi; Nguyen, Hien Anh; Le, Minh Nhat; Dinh Vu, Thiem; Yoshino, Hiroshi; Schmidt, Wolf-Peter; Nguyen, Thi Thuy Ai; Le, Huu Tho; Morimoto, Konosuke; Moriuchi, Hiroyuki; Dang, Duc Anh; Ariyoshi, Koya

2013-08-01

181

Viral MicroRNAs Targeting Virus Genes Promote Virus Infection in Shrimp In Vivo  

PubMed Central

Viral microRNAs (miRNAs), most of which are characterized in cell lines, have been found to play important roles in the virus life cycle to avoid attack by the host immune system or to keep virus in the latency state. Viral miRNAs targeting virus genes can inhibit virus infection. In this study, in vivo findings in Marsupenaeus japonicus shrimp revealed that the viral miRNAs could target virus genes and further promote the virus infection. The results showed that white spot syndrome virus (WSSV)-encoded miRNAs WSSV-miR-66 and WSSV-miR-68 were transcribed at the early stage of WSSV infection. When the expression of WSSV-miR-66 and WSSV-miR-68 was silenced with sequence-specific anti-miRNA oligonucleotides (AMOs), the number of copies of WSSV and the WSSV-infected shrimp mortality were significantly decreased, indicating that the two viral miRNAs had a great effect on virus infection. It was revealed that the WSSV wsv094 and wsv177 genes were the targets of WSSV-miR-66 and that the wsv248 and wsv309 genes were the targets of WSSV-miR-68. The data demonstrate that the four target genes play negative roles in the WSSV infection. The targeting of the four virus genes by WSSV-miR-66 and WSSV-miR-68 led to the promotion of virus infection. Therefore, our in vivo findings show a novel aspect of viral miRNAs in virus-host interactions.

He, Yaodong; Yang, Kai

2014-01-01

182

Pathogenesis of Sendai Virus Infection in Mice.  

National Technical Information Service (NTIS)

Mice experimentally exposed to Sendai virus (Myxovirus parainfluenza type I) by aerosol developed virus titers in both nasal washings and lungs that peaked at 5 or 6 days after exposure and disappeared by 12 days after exposure. Hemagglutination-inhibitio...

J. M. Reddecliff L. H. Appell P. J. Gerone R. M. Kovatch

1970-01-01

183

Evaluating the protective efficacy of a trivalent vaccine containing Akabane virus, Aino virus and Chuzan virus against Schmallenberg virus infection  

PubMed Central

Schmallenberg virus (SBV), an arthropod borne pathogen, spread rapidly throughout the majority of Europe since 2011. It can cause a febrile disease, milk drop, diarrhea, and fetal malformation in ruminants. SBV, a member of the Simbu serogroup within the genus Orthobunyavirus, is closely related to Akabane virus (AKAV) and Aino virus (AINOV) among others. In the present study, 4 Holstein-Friesian calves were immunized twice four weeks apart with a multivalent, inactivated vaccine against AKAV and AINOV. Another 4 calves were kept as unvaccinated controls. All animals were clinically, serologically and virologically examined before and after challenge infection with SBV. AKAV- and AINOV-specific neutralizing antibodies were detected one week before challenge infection, while SBV-specific antibodies were detectable only thereafter. SBV genome was detected in all vaccinated animals and 3 out of 4 controls in serum samples taken after challenge infection. In conclusion, the investigated vaccine was not able to prevent an SBV-infection. Thus, vaccines for other related Simbu serogroup viruses can not substitute SBV-specific vaccines as an instrument for disease control.

2013-01-01

184

Inhalational monkeypox virus infection in cynomolgus macaques  

PubMed Central

An inhalation exposure system was characterized to deliver aerosolized monkeypox virus (MPXV), and a non-human primate (NHP) inhalation monkeypox model was developed in cynomolgus macaques. A head-only aerosol exposure system was characterized, and two sampling methods were evaluated: liquid impingement via an impinger and impaction via a gelatin filter. The aerosol concentrations obtained with the gelatin filter and impinger were virtually identical, indicating that either method is acceptable for sampling aerosols containing MPXV. The mass median aerodynamic diameter (MMAD) for individual aerosol tests in the aerosol system characterization and the NHP study ranged from 1.08 to 1.15 ?m, indicating that the aerosol particles were of a sufficient size to reach the alveoli. Six cynomolgus macaques (four male and two female) were used on study. The animals were aerosol exposed with MPXV and received doses between 2.51 × 104 to 9.28 × 105 plaque forming units (PFUs) inhaled. Four of the six animals died or were euthanized due to their moribund conditions. Both animals that received the lowest exposure doses survived to the end of the observation period. The inhalation LD50 was determined to be approximately 7.8 × 104 pfu inhaled. These data demonstrate that an inhalation MPXV infection model has been developed in the cynomolgus macaque with disease course and lethal dose similar to previously published data.

Barnewall, Roy E.; Fisher, David A.; Robertson, Ashley B.; Vales, Pauline A.; Knostman, Katherine A.; Bigger, John E.

2012-01-01

185

Mitochondrial dysfunction in hepatitis C virus infection.  

PubMed

The mechanisms of liver injury in chronic hepatitis C virus (HCV) infection are poorly understood though HCV induces a state of hepatic oxidative stress that is more pronounced than that present in many other inflammatory diseases. This mini-review will focus on recent findings revealing an unexpected role of mitochondria in providing a central role in the innate immunity and in addition will illustrate the application of stably transfected human-derived cell lines, inducibly expressing the entire HCV open reading frame for in vitro studies on mitochondria. Results obtained by a comparative analysis of the respiratory chain complexes activities along with mitochondrial morpho-functional confocal microscopy imaging show a detrimental effect of HCV proteins on the cell oxidative metabolism with specific inhibition of complex I activity, decrease of mtDeltaPsi, increased production of reactive oxygen species. A possible de-regulation of calcium recycling between the endoplasmic reticulum and the mitochondrial network is discussed to provide new insights in the pathogenesis of hepatitis C. PMID:16814246

Piccoli, C; Scrima, R; D'Aprile, A; Ripoli, M; Lecce, L; Boffoli, D; Capitanio, N

2006-01-01

186

[Malpighian epithelia infected by DNA viruses and Langerhans cells].  

PubMed

Malpighian epithelia exhibit an immune surveillance through Langerhans cells (LC) against the DNA viruses, which induce various epithelial lesions, mainly on the skin, conjunctiva, mouth, uterine cervix. These viral infections are usual during childhood. The most common DNA viruses are: adenoviruses (more than 40 types), human papillomaviruses (HPV, more than 50 types) and Herpes viruses (herpes simplex type 1 and 2, varicella and Zooster, Epstein-Barr virus). Different clinical aspects are observed (exanthema, erythema, eruption, papillomas, vesicle, bullous) are well as histological signs. All of these viruses are replicating in the nuclei of epithelial cells which show eosinophilic inclusions and finally cell degeneresence with a typical aspect for each virus such as koilocyte for HPV infection. These lesions are commonly infiltrated with T lymphocytes; the intensity of the local cellular immune response varies with the lesion. LC are reduced in infected epithelia; they are sometimes found in conjunctive tissues and their morphology can be altered; their role in antigen presentation to T lymphocytes has only been demonstrated in herpes simplex virus infections. Profound modifications of membrane antigens of epithelial cells (loss of HLA class 1 antigen) might contribute to the disappearance of LC or to their functional inability. Most of the DNA virus infections are inapparent, benign and transient. However some lesions can evolve towards malignancy; this progression depends on the oncogenic potential of the viruses (such as HPV types 16 and 18 or herpes simplex virus type 2) associated to a local or a general immune deficiency of the patient as well as to other exogenous factors (UV for example). PMID:2694082

Chardonnet, Y; Viac, J; Schmitt, D

1989-10-01

187

Senescence Affects Endothelial Cells Susceptibility to Dengue Virus Infection  

PubMed Central

Alteration in the endothelium leading to increased vascular permeability contributes to plasma leakage seen in dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). An earlier study showed that senescent endothelial cells (ECs) altered the ECs permeability. Here we investigated the susceptibility of senescing human umbilical vein endothelial cells (HUVECs) to dengue virus infection and determined if dengue virus infection induces HUVECs senescence. Our results suggest that DENV type-2 (DENV-2) foci forming unit (FFU) and extracellular virus RNA copy number were reduced by at least 35% and 85% in infection of the intermediate young and early senescent HUVECs, respectively, in comparison to infection of young HUVECs. No to low infectivity was recovered from infection of late senescent HUVECs. DENV infection also increases the percentage of HUVECs expressing senescence-associated (SA)-?-gal, cells arrested at the G2/M phase or 4N DNA content stage and cells with enlarged morphology, indicative of senescing cells. Alteration of HUVECs morphology was recorded using impedance-based real-time cell analysis system following DENV-2 infection. These results suggest that senescing HUVECs do not support DENV infection and DENV infection induces HUVECs senescence. The finding highlights the possible role of induction of senescence in DENV infection of the endothelial cells.

AbuBakar, Sazaly; Shu, Meng-Hooi; Johari, Jefree; Wong, Pooi-Fong

2014-01-01

188

Simian Varicella Virus Infection of Rhesus Macaques Recapitulates Essential Features of Varicella Zoster Virus Infection in Humans  

Microsoft Academic Search

Simian varicella virus (SVV), the etiologic agent of naturally occurring varicella in primates, is genetically and antigenically closely related to human varicella zoster virus (VZV). Early attempts to develop a model of VZV pathogenesis and latency in nonhuman primates (NHP) resulted in persistent infection. More recent models successfully produced latency; however, only a minority of monkeys became viremic and seroconverted.

Ilhem Messaoudi; Alexander Barron; Mary Wellish; Flora Engelmann; Alfred Legasse; Shannon Planer; Don Gilden; Janko Nikolich-Zugich; Ravi Mahalingam

2009-01-01

189

Natural infection of turkeys by infectious laryngotracheitis virus.  

PubMed

The infectious laryngotracheitis virus (ILTV) is an important respiratory pathogen of chickens that also infects pheasants and peafowl. Epidemiologically non-related commercial turkey flocks with clinical signs such as tracheitis, swollen sinuses, conjunctivitis and expectoration of bloody mucus were examined for the presence of the virus. Laboratory ILTV detection was performed by virus isolation in embryonated eggs and cell cultures, PCR and sequencing of amplification products, histopathology, indirect immunofluorescence and electron microscopy. One ILTV turkey isolate was also experimentally inoculated into susceptible chickens and turkeys, reproducing a mild respiratory disease. This is the first description of natural infections with ILTV in turkeys. PMID:18436397

Portz, Cristiana; Beltrão, Nilzane; Furian, Thales Quedi; Júnior, Alfredo Bianco; Macagnan, Marisa; Griebeler, Josiane; Lima Rosa, Carlos André Veiga; Colodel, Edson Moleta; Driemeier, David; Back, Alberto; Barth Schatzmayr, Ortrud Monika; Canal, Cláudio Wageck

2008-09-18

190

Preference by a virus vector for infected plants is reversed after virus acquisition.  

PubMed

Pathogens and their vectors can interact either directly or indirectly via their shared hosts, with implications for the persistence and spread of the pathogen in host populations. For example, some plant viruses induce changes in host plants that cause the aphids that carry these viruses to settle preferentially on infected plants. Furthermore, relative preference by the vector for infected plants can change to a preference for noninfected plants after virus acquisition by the vector, as has recently been demonstrated in the wheat-Rhopalosiphum padi-Barley yellow dwarf virus pathosystem. Here we document a similar dynamic in the potato-Myzus persicae (Sulzer)-Potato leaf roll virus (PLRV) pathosystem. Specifically, in a dual choice bioassay, nonviruliferous apterous M. persicae settled preferentially on or near potato plants infected with PLRV relative to noninfected (sham-inoculated) control plants, whereas viruliferous M. persicae (carrying PLRV) preferentially settled on or near sham-inoculated potato plants relative to infected plants. The change in preference after virus acquisition also occurred in response to trapped headspace volatiles, and to synthetic mimics of headspace volatile blends from PLRV-infected and sham-inoculated potato plants. The change in preference we document should promote virus spread by increasing rates of virus acquisition and transmission by the vector. PMID:24269348

Rajabaskar, Dheivasigamani; Bosque-Pérez, Nilsa A; Eigenbrode, Sanford D

2014-06-24

191

Structural aberrations in T-even bacteriophage. IX. Effect of mixed infection on the production of giant bacteriophage.  

PubMed Central

To date, the production of T-even bacteriophage with giant heads has been achieved in two ways: (i) by use of canavanine-arginine treatment of Escherichia coli B cultures infected by wild-type bacteriophage (Cummings and Bolin, Bacteriol. Rev. 40:314-359, 1976; Cummings et al., Virology 54:245-261, 1973), which give a size distribution of giants that is phage specific (Cummings et al., Virology 54:245-261, 1973); and (ii) by infection with certain missense mutants of T4D gene 23 (Doermann et al., J. Virol. 12:374-385, 1973; ICN-UCLA Symposium on Molecular Biology, p. 243-285, 1973) or temperature-sensitive mutants of gene 24 (Aebi et al., J. Supramol. Struct. 2:253-275, 1974; Biljenga et al., J. Mol. Biol. 103:469-498, 1976). We now report the effect of mixed infection with several mutants of T4D on both the production and the size of giant bacteriophage. We found that gene 24 mutant is a critical partner for the production of giants. Infection using T4.24 mutants together with either T4.23 mutants, T4B+ or T6+ led to the formation of giants with heads 10- to 14-fold longer than normal-length heads. Infection with amber 24-bypass 24 double mutants of T4D led to the production of giants when gene 23 mutant was used to co-infect. Addition of canavanine to the co-infected cultures could alter the size distribution of giants, depending on which phage were used to coinfect. Gene 22 mutants had a modifying effect on these results. In the absence of canavanine co-infection with gene 22 mutants prevented the production of giants, and in the presence of canavanine giants of 1.5 to 5 head lengths were found. We have interpreted these results to mean that critical concentrations of gene products 22, 23, and 24 interact to control head length in T-even bacteriophage. Images

Cummings, D J; Chapman, V A; DeLong, S S

1977-01-01

192

[Immunosuppression in dogs and pigs infected with canine distemper virus].  

PubMed

Immunosuppression manifesting itself as leukopenia and a considerably lower lymphocyte proliferative response to T- and B-cell mitogens develops in pigs and dogs within 2-3 weeks after intramuscular or oral infection with canine distemper virus (CDV). CDV antigens are detectable in the oral secretions of the animals within 2-2.5 week after infection. PMID:22171479

Sereda, A D; Nogina, I V

2011-01-01

193

Intrauterine herpes simplex virus infection presenting with hypopigmented lesions.  

PubMed

Genital herpes simplex virus (HSV) is a sexually transmitted infection that can be transmitted from mother to child in utero, perinatally, or postnatally. Cutaneous infection with HSV commonly presents as vesicles affecting the skin, eyes, or mouth. In our case, we report a well child with cutaneous hypopigmented patches at birth that preceded typical blistering. PMID:22010816

Low, Lynette C M; Carton, James; Walker, Marjorie; Tudor-Williams, Gareth; Hardman, Catherine

2012-01-01

194

A mathematical model for acute hepatitis B virus infection  

Microsoft Academic Search

Based on the clinical data of acute hepatitis B patients and the HBV infection dynamic model proposed by Nowak et al., we construct a mathematical model to describe and understand the dynamics of host cells, virus and the immune system during the acute stages of the infection. Our model provide a possible interpretation for the phenomenon of acute hepatitis and

Lijuan Du; Dongwei Huang; Qizhi Xie

2010-01-01

195

Seronegative Hepatitis C Virus Infection in a Child Infected via Mother-to-Child Transmission  

PubMed Central

Hepatitis C virus (HCV) infection typically leads to antibody response within weeks after primary infection. Here, we describe the case of a child infected with HCV by mother-to-child transmission who remained persistently seronegative despite the presence of high levels of circulating HCV RNA.

Larouche, Ariane; Gaetan, Genevieve; El-Bilali, Nabil; Quesnel-Vallieres, Mathieu; Martin, Steven R.; Alvarez, Fernando; Shoukry, Naglaa H.

2012-01-01

196

Immune Modulation in Primary Vaccinia virus Zoonotic Human Infections  

PubMed Central

In 2010, the WHO celebrated the 30th anniversary of the smallpox eradication. Ironically, infections caused by viruses related to smallpox are being increasingly reported worldwide, including Monkeypox, Cowpox, and Vaccinia virus (VACV). Little is known about the human immunological responses elicited during acute infections caused by orthopoxviruses. We have followed VACV zoonotic outbreaks taking place in Brazil and analyzed cellular immune responses in patients acutely infected by VACV. Results indicated that these patients show a biased immune modulation when compared to noninfected controls. Amounts of B cells are low and less activated in infected patients. Although present, T CD4+ cells are also less activated when compared to noninfected individuals, and so are monocytes/macrophages. Similar results were obtained when Balb/C mice were experimentally infected with a VACV sample isolated during the zoonotic outbreaks. Taking together, the data suggest that zoonotic VACVs modulate specific immune cell compartments during an acute infection in humans.

Gomes, Juliana Assis Silva; de Araujo, Fernanda Fortes; Trindade, Giliane de Souza; Quinan, Barbara Resende; Drumond, Betania Paiva; Ferreira, Jaqueline Maria Siqueira; Mota, Bruno Eduardo Fernandes; Nogueira, Mauricio Lacerda; Kroon, Erna Geessien; Abrahao, Jonatas Santos; Correa-Oliveira, Rodrigo; da Fonseca, Flavio Guimaraes

2012-01-01

197

Persistent infection of rabbits with bovine immunodeficiency-like virus.  

PubMed Central

Chronic infection of rabbits was induced by a single intraperitoneal injection of bovine immunodeficiency-like virus (BIV)-infected cells. Ten BIV-infected animals were monitored serologically for up to 2 years. Results of serologic and virus rescue assays indicated that all animals became infected and demonstrated a rapid and sustained BIV-specific humoral response. BIV was rescued by cocultivation from spleen, lymph nodes, and peripheral blood leukocytes of infected animals. Viral DNA in immune tissues was confirmed by polymerase chain reaction amplification of BIV sequences. These data and specific immunohistochemical staining of mononuclear cells of the spleen for BIV antigen suggest that the infection is targeted to immune system cells. Images

Pifat, D Y; Ennis, W H; Ward, J M; Oberste, M S; Gonda, M A

1992-01-01

198

Acute hepatitis A virus infections in British Gurkha soldiers.  

PubMed

Hepatitis A virus (HAV) and hepatitis E virus (HEV) infections are endemic in most developing countries, including Nepal and Afghanistan, and may cause outbreaks in military personnel. Previously, more than 99% of new British Gurkha recruits were already immune to HAV because of prior infection, but this may be declining due to improved living conditions in their countries of origin. Acute HAV infections have occurred in Gurkha soldiers serving in Afghanistan, which made them unfit for duty for 2-3 months. In one case, early serological diagnosis was impeded by IgM results against both HAV and HEV that were caused by cross-reactivity or persistence from a previous infection. These cases have led to a policy change whereby all Gurkha recruits are now tested for previous HAV infection and if negative they are offered vaccination. Meanwhile, HEV infection remains a significant threat in Nepal and Afghanistan with low levels of background immunity and no commercially available vaccine. PMID:23720504

Green, Chris A; Ross, D A; Bailey, M S

2013-09-01

199

Innate immunity and hepatitis C virus infection: a microarray's view  

PubMed Central

Hepatitis C virus (HCV) induces a chronic infection in more than two-thirds of HCV infected subjects. The inefficient innate and adaptive immune responses have been shown to play a major pathogenetic role in the development and persistence of HCV chronic infection. Several aspects of the interactions between the virus and the host immune system have been clarified and, in particular, mechanisms have been identified which underlie the ability of HCV to seize and subvert innate as well as adaptive immune responses. The present review summarizes recent findings on the interaction between HCV infection and innate immune response whose final effect is the downstream inefficient development of antigen-specific adaptive immunity, thereby contributing to virus persistence.

2012-01-01

200

Virus Enrichment for Single Virus Infection by Using 3D Insulator Based Dielectrophoresis.  

PubMed

We developed an active virus filter (AVF) that enables virus enrichment for single virus infection, by using insulator-based dielectrophoresis (iDEP). A 3D-constricted flow channel design enabled the production of an iDEP force in the microfluidic chip. iDEP using a chip with multiple active virus filters (AVFs) was more accurate and faster than using a chip with a single AVF, and improved the efficiency of virus trapping. We utilized maskless photolithography to achieve the precise 3D gray-scale exposure required for fabrication of constricted flow channel. Influenza virus (A PR/8) was enriched by a negative DEP force when sinusoidal wave was applied to the electrodes within an amplitude range of 20 Vp-p and a frequency of 10 MHz. AVF-mediated virus enrichment can be repeated simply by turning the current ON or OFF. Furthermore, the negative AVF can inhibit virus adhesion onto the glass substrate. We then trapped and transported one of the enriched viruses by using optical tweezers. This microfluidic chip facilitated the effective transport of a single virus from AVFs towards the cell-containing chamber without crossing an electrode. We successfully transported the virus to the cell chamber (v?=?10 µm/s) and brought it infected with a selected single H292 cell. PMID:24918921

Masuda, Taisuke; Maruyama, Hisataka; Honda, Ayae; Arai, Fumihito

2014-01-01

201

An ssDNA virus infecting archaea: a new lineage of viruses with a membrane envelope.  

PubMed

Archaeal organisms are generally known as diverse extremophiles, but they play a crucial role also in moderate environments. So far, only about 50 archaeal viruses have been described in some detail. Despite this, unusual viral morphotypes within this group have been reported. Interestingly, all isolated archaeal viruses have a double-stranded DNA (dsDNA) genome. To further characterize the diversity of archaeal viruses, we screened highly saline water samples for archaea and their viruses. Here, we describe a new haloarchaeal virus, Halorubrum pleomorphic virus 1 (HRPV-1) that was isolated from a solar saltern and infects an indigenous host belonging to the genus Halorubrum. Infection does not cause cell lysis, but slightly retards growth of the host and results in high replication of the virus. The sequenced genome (7048 nucleotides) of HRPV-1 is single-stranded DNA (ssDNA), which makes HRPV-1 the first characterized archaeal virus that does not have a dsDNA genome. In spite of this, similarities to another archaeal virus were observed. Two major structural proteins were recognized in protein analyses, and by lipid analyses it was shown that the virion contains a membrane. Electron microscopy studies indicate that the enveloped virion is pleomorphic (approximately 44 x 55 nm). HRPV-1 virion may represent commonly used virion architecture, and it seems that structure-based virus lineages may be extended to non-icosahedral viruses. PMID:19298373

Pietilä, Maija K; Roine, Elina; Paulin, Lars; Kalkkinen, Nisse; Bamford, Dennis H

2009-04-01

202

Virus Enrichment for Single Virus Infection by Using 3D Insulator Based Dielectrophoresis  

PubMed Central

We developed an active virus filter (AVF) that enables virus enrichment for single virus infection, by using insulator-based dielectrophoresis (iDEP). A 3D-constricted flow channel design enabled the production of an iDEP force in the microfluidic chip. iDEP using a chip with multiple active virus filters (AVFs) was more accurate and faster than using a chip with a single AVF, and improved the efficiency of virus trapping. We utilized maskless photolithography to achieve the precise 3D gray-scale exposure required for fabrication of constricted flow channel. Influenza virus (A PR/8) was enriched by a negative DEP force when sinusoidal wave was applied to the electrodes within an amplitude range of 20 Vp-p and a frequency of 10 MHz. AVF-mediated virus enrichment can be repeated simply by turning the current ON or OFF. Furthermore, the negative AVF can inhibit virus adhesion onto the glass substrate. We then trapped and transported one of the enriched viruses by using optical tweezers. This microfluidic chip facilitated the effective transport of a single virus from AVFs towards the cell-containing chamber without crossing an electrode. We successfully transported the virus to the cell chamber (v?=?10 µm/s) and brought it infected with a selected single H292 cell.

Masuda, Taisuke; Maruyama, Hisataka; Honda, Ayae; Arai, Fumihito

2014-01-01

203

Cowpea Mosaic Virus infection of protoplast from Samsun tobacco leaves  

Microsoft Academic Search

SUMMARY Palisade parenchyma protoplasts isolated from the tobacco varieties Samsun and Samsun NN were inoculated in vitro with cowpea mosaic virus (CPMV). By fluorescent antibody staining it was demonstrated that about 75 o\\/o of the proto- plasts became infected. Poly-L-ornithine was required for infection. The cytopathic structures shown previously to be characteristic for CPMV-infected cowpea cells were also produced in

R. M. Huber; G. Rezelman; Kammen van A; A. van Kammen

1977-01-01

204

Multiple Epstein-Barr virus infections in healthy individuals  

NASA Technical Reports Server (NTRS)

We employed a newly developed genotyping technique with direct representational detection of LMP-1 gene sequences to study the molecular epidemiology of Epstein-Barr virus (EBV) infection in healthy individuals. Infections with up to five different EBV genotypes were found in two of nine individuals studied. These results support the hypothesis that multiple EBV infections of healthy individuals are common. The implications for the development of an EBV vaccine are discussed.

Walling, Dennis M.; Brown, Abigail L.; Etienne, Wiguins; Keitel, Wendy A.; Ling, Paul D.; Butel, J. S. (Principal Investigator)

2003-01-01

205

Risk of Lymphoma Increases with Hepatitis C Virus Infection  

Cancer.gov

People infected with the hepatitis C virus (HCV) are at an increased risk of developing certain lymphomas (cancers of the lymphatic system). Researchers found that HCV infection increased the risk of developing non-Hodgkin's lymphoma by 20 percent to 30 percent. The risk of developing Waldenström's macroglobulinemia (a rare type of non-Hodgkin's lymphoma) went up by 300 percent and the risk for cryoglobulinemia, a form of blood vessel inflammation, was also elevated for those with HCV infections.

206

Hepatitis C Virus Infection and Its Rheumatologic Implications  

PubMed Central

Extrahepatic manifestations are frequently encountered among patients with chronic hepatitis C virus (HCV) infection. Many of these manifestations are autoimmune disorders, with added mortality and morbidity due to involvement of multiple organ systems. Symptoms of HCV infection and rheumatic diseases may be similar and include arthralgia, myalgia, arthritis, and vasculitis. Also, serologic abnormalities may be found in both cases. Some treatment modalities for HCV infection, including interferon therapy, may aggravate the symptoms of rheumatic diseases, thus confounding clinical presentation. It is imperative to distinguish whether symptoms such as arthralgia, myalgia, and arthritis occur in patients with HCV infection due to primary chronic HCV infection or to a newly developed rheumatologic disease process.

Sayiner, Zeynel A.; Haque, Uzma; Malik, Mohammad U.

2014-01-01

207

Epidemiology of Hepatitis C Virus (HCV) Infection  

PubMed Central

Hepatitis C virus remains a large health care burden to the world. Incidence rates across the world fluctuate and are difficult to calculate given the asymptomatic, often latent nature of the disease prior to clinical presentation. Prevalence rates across the world have changed as well with more countries aware of transfusion-related hepatitis C and more and more evidence supporting intravenous drug use as the leading risk factor of spread of the virus. This article reviews current hepatitis C virus prevalence and genotype data and examines the different risk factors associated with the virus.

Sy, Theodore; Jamal, M. Mazen

2006-01-01

208

Hepatitis E Virus Infection among Solid Organ Transplant Recipients, the Netherlands  

PubMed Central

We screened 1,200 living heart, lung, liver, and kidney transplant recipients for hepatitis E virus infection by reverse transcription PCR. In 12 (1%) patients, hepatitis E virus infection was identified; in 11 patients, chronic infection developed. This immunocompromised population is at risk for hepatitis E virus infection.

Pas, Suzan D.; de Man, Rob A.; Mulders, Claudia; Balk, Aggie H.M.M.; van Hal, Peter T.W.; Weimar, Willem; Koopmans, Marion P.G.; Osterhaus, Albert D.M.E.

2012-01-01

209

Bacterial Sinusitis and Otitis Media following Influenza Virus Infection in Ferrets  

Microsoft Academic Search

Streptococcus pneumoniae is the leading cause of otitis media, sinusitis, and pneumonia. Many of these infections result from antecedent influenza virus infections. In this study we sought to determine whether the frequency and character of secondary pneumococcal infections differed depending on the strain of influenza virus that preceded bacterial challenge. In young ferrets infected with influenza virus and then challenged

Ville T. Peltola; Kelli L. Boyd; Julie L. McAuley; Jerold E. Rehg; Jonathan A. McCullers

2006-01-01

210

Infection of cells by Sindbis virus at low temperature  

SciTech Connect

Sindbis virus, which belongs to the family Togaviridae genus Alphavirus infects a variety of vertebrate and invertebrate cells. The initial steps of Sindbis virus infection involve attachment, penetration and uncoating. Two different pathways of infection have been proposed for Alphaviruses. One proposed mechanism involves receptor mediated virion endocytosis followed by membrane fusion triggered by endosome acidification. This virus-host membrane fusion model, well established by influenza virus, has been applied to other unrelated membrane-containing viruses including Alphaviruses. The other mechanism proposes direct penetration of the cell plasma membrane by the virus glycoproteins in the absence of membrane fusion. This alternate model is supported by both ultrastructural [Paredes, A.M., Ferreira, D., Horton, M., Saad, A., Tsuruta, H., Johnston, R., Klimstra, W., Ryman, K., Hernandez, R., Chiu, W., Brown, D.T., 2004. Conformational changes in Sindbis virions resulting from exposure to low pH and interactions with cells suggest that cell penetration may occur at the cell surface in the absence of membrane fusion. Virology 324(2), 373-386] and biochemical [Koschinski, A., Wengler, G., Wengler, G., and Repp, H., 2005. Rare earth ions block the ion pores generated by the class II fusion proteins of alphaviruses and allow analysis of the biological functions of these pores. J. Gen. Virol. 86(Pt. 12), 3311-3320] studies. We have examined the ability of Sindbis virus to infect Baby Hamster Kidney (BHK) cells at temperatures which block endocytosis. We have found that under these conditions Sindbis virus infects cells in a temperature- and time-dependent fashion.

Wang Gongbo [Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695 (United States); Hernandez, Raquel [Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695 (United States); Weninger, Keith [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Brown, Dennis T. [Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695 (United States)]. E-mail: dennis_brown@ncsu.edu

2007-06-05

211

Respiratory virus infections among children in South China.  

PubMed

Acute respiratory tract infection is an important cause of morbidity and mortality with a worldwide disease burden. This study aimed to determine the prevalence and clinical characteristics of children with viral-induced acute respiratory tract infection, in Southern China. Nasopharyngeal aspirate samples from 1,980 pediatric patients with suspected acute respiratory tract infection, and 82 samples from healthy subject controls were collected for routine examination at the Second Affiliated Hospital of Shantou University Medical College, from October 2007 to August 2011. Specimens were tested by multiplex polymerase chain reaction (mPCR). At least one or more viruses were detected from 1,087 samples (54.9%). These included laboratory confirmations for 446 respiratory syncytial virus (RSV), 386 influenza virus A (FluA), 315 human rhinovirus (HRV), 135 human bocavirus (HBoV), 119 Parainfluenza virus 3 (PIV3), 82 Parainfluenza virus 1 (PIV1), 66 adenovirus (ADV), 53 WU polyomavirus (WUPyV), 52 human metapneumovirus (hMPV), and 29 influenza virus B (FluB) samples. Samples from healthy subjects were negative for any virus. Of the patients with positive specimens, 107 (9.8%) were admitted to pediatric intensive care unit (PICU). Co-infection with at least two of the viral pathogens under study was observed in 325 of the 1,980 patients (16.4% of the total number of cases). These findings may help in the diagnosis of viral infections of the respiratory tract in children, and help to consider current and potential therapeutic approaches for the treatment of acute respiratory tract infection, and further respiratory complications. PMID:24619492

Cai, Xiao-Ying; Wang, Qiong; Lin, Guang-Yu; Cai, Zhi-Wei; Lin, Chuang-Xing; Chen, Pai-Zhen; Zhou, Xiao-Hua; Xie, Jin-Chun; Lu, Xue-Dong

2014-07-01

212

Incorporation of adenylate cyclase into membranes of giant liposomes using membrane fusion with recombinant baculovirus-budded virus particles.  

PubMed

Recombinant transmembrane adenylate cyclase (AC) was incorporated into membranes of giant liposomes using membrane fusion between liposomes and baculovirus-budded virus (BV). AC genes were constructed into transfer vectors in a form fused with fluorescent protein or polyhistidine at the C-terminus. The recombinant BVs were collected by ultracentrifugation and AC expression was verified using western blotting. The BVs and giant liposomes generated using gentle hydration were fused under acidic conditions; the incorporation of AC into giant liposomes was demonstrated by confocal laser scanning microscopy through the emission of fluorescence from their membranes. The AC-expressing BVs were also fused with liposomes containing the substrate (ATP) with/without a specific inhibitor (SQ 22536). An enzyme immunoassay on extracts of the sample demonstrated that cAMP was produced inside the liposomes. This procedure facilitates direct introduction of large transmembrane proteins into artificial membranes without solubilization. PMID:24563316

Mori, Takaaki; Kamiya, Koki; Tomita, Masahiro; Yoshimura, Tetsuro; Tsumoto, Kanta

2014-06-01

213

A case of Ebola virus infection  

Microsoft Academic Search

In November 1976 an investigator at the Microbiological Research Establishment accidentally inoculated himself while processing material from patients in Africa who had been suffering from a haemorrhagic fever of unknown cause. He developed an illness closely resembling Marburg disease, and a virus was isolated from his blood that resembled Marburg virus but was distinct serologically. The course of the illness

R T Emond; B Evans; Etw Bowen; G Lloyd

1977-01-01

214

A FILTERABLE VIRUS INFECTION OF RABBITS  

PubMed Central

1. Blood and joint fluid of patients suffering from rheumatic fever were inoculated into the testicles of rabbits, and transfers were made from testicle to testicle at varying intervals. In three series, in none of which were the periods between the transfers longer than 4 days, a virus was recovered which produced acute orchitis in rabbits. The virus could be indefinitely propagated from rabbit to rabbit. 2. Intradermal inoculation of the virus led to the appearance of raised erythematous lesions in 3 to 6 days. 3. Intrathoracic inoculations near the heart led to a fibrinous pericarditis in three out of five rabbits, and to a myocarditis in one. 4. Nuclear inclusion bodies staining pink with eosin were found in the lesions in the testis, skin, pericardium, and heart muscle. 5. Rabbits inoculated into skin or testes were refractory, 2 weeks later, to further intradermal inoculations; after this interval their serum had developed the power to neutralize the virus in vitro. 6. The virus can be preserved in 50 per cent glycerol for at least 18 days. It can be preserved after freezing and drying for at least 8 days and probably for 10 weeks. 7. Cross-immunity tests point to the identity of the virus with that described by Rivers and Tillett in their studies on chicken-pox as Virus III. 8. These facts together with the failure of rheumatic fever sera to neutralize the virus indicate that it bears no etiologic relationship to rheumatic fever.

Miller, C. Philip; Andrewes, C. H.; Swift, Homer F.

1924-01-01

215

Pathogenesis of Lassa fever virus infection: I. Susceptibility of mice to recombinant Lassa Gp/LCMV chimeric virus.  

PubMed

Lassa virus (LASV) is a BSL-4 restricted agent. To allow study of infection by LASV under BSL-2 conditions, we generated a recombinant virus in which the LASV glycoprotein (Gp) was placed on the backbone of lymphocytic choriomeningitis virus (LCMV) Cl13 nucleoprotein, Z and polymerase genes (rLCMV Cl13/LASV Gp). The recombinant virus displayed high tropism for dendritic cells following in vitro or in vivo infection. Inoculation of immunocompetent adults resulted in an acute infection, generation of virus-specific CD8(+) T cells and clearance of the infection. Inoculation of newborn mice with rLCMV Cl13/LASV Gp resulted in a life-long persistent infection. Interestingly, adoptive transfer of rLCMV Cl13/LASV Gp immune memory cells into such persistently infected mice failed to purge virus but, in contrast, cleared virus from mice persistently infected with wt LCMV Cl13. PMID:23684417

Lee, Andrew M; Cruite, Justin; Welch, Megan J; Sullivan, Brian; Oldstone, Michael B A

2013-08-01

216

Persistent Hepatitis C Virus Infection In Vitro: Coevolution of Virus and Host?†  

PubMed Central

The virological and cellular consequences of persistent hepatitis C virus (HCV) infection have been elusive due to the absence of the requisite experimental systems. Here, we report the establishment and the characteristics of persistent in vitro infection of human hepatoma-derived cells by a recently described HCV genotype 2a infectious molecular clone. Persistent in vitro infection was characterized by the selection of viral variants that displayed accelerated expansion kinetics, higher peak titers, and increased buoyant densities. Sequencing analysis revealed the selection of a single adaptive mutation in the HCV E2 envelope protein that was largely responsible for the variant phenotype. In parallel, as the virus became more aggressive, cells that were resistant to infection emerged, displaying escape mechanisms operative at the level of viral entry, HCV RNA replication, or both. Collectively, these results reveal the existence of coevolutionary events during persistent HCV infection that favor survival of both virus and host.

Zhong, Jin; Gastaminza, Pablo; Chung, Josan; Stamataki, Zania; Isogawa, Masanori; Cheng, Guofeng; McKeating, Jane A.; Chisari, Francis V.

2006-01-01

217

Persistent hepatitis C virus infection in vitro: coevolution of virus and host.  

PubMed

The virological and cellular consequences of persistent hepatitis C virus (HCV) infection have been elusive due to the absence of the requisite experimental systems. Here, we report the establishment and the characteristics of persistent in vitro infection of human hepatoma-derived cells by a recently described HCV genotype 2a infectious molecular clone. Persistent in vitro infection was characterized by the selection of viral variants that displayed accelerated expansion kinetics, higher peak titers, and increased buoyant densities. Sequencing analysis revealed the selection of a single adaptive mutation in the HCV E2 envelope protein that was largely responsible for the variant phenotype. In parallel, as the virus became more aggressive, cells that were resistant to infection emerged, displaying escape mechanisms operative at the level of viral entry, HCV RNA replication, or both. Collectively, these results reveal the existence of coevolutionary events during persistent HCV infection that favor survival of both virus and host. PMID:16956932

Zhong, Jin; Gastaminza, Pablo; Chung, Josan; Stamataki, Zania; Isogawa, Masanori; Cheng, Guofeng; McKeating, Jane A; Chisari, Francis V

2006-11-01

218

[Infection with parvovirus B 19 virus in humans].  

PubMed

Human parvovirus B 19 (B 19) causes endemic infections in Germany. Most frequently. B 19 infection is associated in with erythema infectiosum. In patients with underlying chronic-haemolytic anaemia, B 19 infection can result in aplastic crisis. In patients with hereditary or acquired immuno-deficiency syndromes, B 19 virus may persist causing chronic bone marrow aplasia. In pregnancy B 19 infection may cause hydrops fetalis resulting in fetal loss. B 19 infection may cause hydrops fetalis resulting in fetal loss. B 19 infection in sometimes associated with vascular purpura. Infections occur mostly as epidemic outbreaks in families, kindergartens and schools as well as hospital wards. Acute or past B 19 infections are confirmed by detection B 10-specific antibodies (IgM/IgM) by ELISA. PMID:8234061

Schwarz, T F; Boro?-Kaczmarska, A

219

Hepatocellular carcinoma in patients co-infected with hepatitis C virus and human immunodeficiency virus.  

PubMed

Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) share a common route of transmission so that about one third of HIV infected individuals show HCV co-infection. Highly active antiretroviral therapy has offered a longer and better life to infected patients. While has removed AIDS-related diseases from the list of most common causes of death their place has been taken by complications of HCV infection, such as cirrhosis, end stage liver disease and hepatocellular carcinoma (HCC). HIV/HCV co-infection requires complex management, especially when HCC is present. Co-infected patients with HCC undergo the same therapeutic protocol as their mono-infected counterparts, but special issues such as interaction between regimens, withdrawal of therapy and choice of immunosuppressive agents, demand a careful approach by specialists. All these issues are analyzed in this minireview. PMID:23805356

Dimitroulis, Dimitrios; Valsami, Serena; Spartalis, Eleftherios; Pikoulis, Emmanuel; Kouraklis, Gregory

2013-06-27

220

Novel clinical features of recurrent human respiratory syncytial virus infections.  

PubMed

Children and elderly individuals are often infected easily and repeatedly with human respiratory syncytial virus (HRSV); however, the features of recurrent infection in the same individual are defined poorly. To clarify the clinical significance of repeated HRSV infections in relation to subgroup epidemiology, this study performed prospective and longitudinal analyses in children with lower respiratory tract infections over 20 consecutive epidemics between 1985 and 2005 at a pediatric outpatient clinic in Kawasaki, Japan. HRSV infections were confirmed by 2 types of reverse-transcription PCR. Samples obtained from patients with repeated infections were subjected to sequence analysis and cloning analysis. A total of 1,312 lower respiratory tract infections observed in 1,010 patients were diagnosed as HRSV infections. Repeated HRSV infections occurred in 208 of the 1,010 patients. Analysis of the patients with repeated infections revealed that children were often infected multiple times even within a single short epidemic. Some patients were re-infected with strains having the same or virtually identical N gene sequences. In patients infected more than 4 times, cloning analysis revealed more frequent dual infections with both subgroups (23.8%). The HRSV-A subgroup caused subsequent homologous infections more frequently than did HRSV-B; furthermore, HRSV-A infections provided no protection from a second homologous infection. In contrast, HRSV-B infections offered significant protection against a second homologous infection. Statistical analysis revealed alleviation of symptoms with a reduced rate of dyspnoeic attacks only in the group re-infected with homologous HRSV-A strains. Thus, this study elucidates new clinical features of recurrent HRSV infection. J. Med. Virol 86: 1629-1638, 2014. © 2013 The Authors Journal of Medical Virology Published by Wiley Periodicals, Inc. PMID:24166209

Yui, Ikuko; Fujino, Motoko; Sawada, Akihito; Nakayama, Tetsuo

2014-09-01

221

SULFONAMIDE CHEMOTHERAPY OF COMBINED INFECTION WITH INFLUENZA VIRUS AND BACTERIA  

PubMed Central

1. Sulfonamide chemotherapy controls the bacterial component of combined infection with influenza virus and pneumococci in rats. 2. Reinstillation of fluid (broth, physiological salt solution) into the respiratory passages of mice several days after sublethal viral infection converts the viral infection into a lethal one. 3. Sulfonamide chemotherapy controls the bacterial component of combined bacterial and viral infection of mice, produced by intrabronchial inoculation of mixtures of bacteria and sublethal or lethal doses of virus. 4. Bacterial pneumonia may be superimposed upon sublethal viral infection in mice by inhalation of fine droplets of bacterial suspension several days after inoculation of virus. Normal mice inhaling fine droplets of bacterial suspension fail to develop obvious disease. 5. Sulfonamide chemotheiapy controls bacterial pneumonia superimposed on sublethal viral infection by inhalation of fine droplets of bacterial culture. 6. The secondary bacterial penumonia does not convert the sublethal viral infection into a lethal one. 7. If another pandemic of influenza occurs, it is probable that sulfonamide chemotherapy will be valuable in the treatment of secondary bacterial pneumonia and will be effective in lowering the case fatality rate if the viral component of the infection is not severe enough by itself to cause death.

Harford, Carl G.; Smith, Mary Ruth; Wood, W. Barry

1946-01-01

222

Sindbis virus infectivity improves during the course of infection in both mammalian and mosquito cells.  

PubMed

Alphaviruses are enveloped, single-stranded positive sense RNA viruses that are transmitted by an arthropod vector to a wide host range, including avian and mammalian species. Arthropods and vertebrates have different cellular environments and this may cause the different cellular pathologies that are observed between the invertebrate vector and vertebrate hosts in both whole organisms and cultured cell lines. In this report, we used Sindbis virus and examined mosquito and mammalian cell lines for their ability to produce progeny virus particles. Total particles produced, viral titers, and overall infectivity (or the ratio of total particles-to-infectious particles) was investigated. Our results show (1) Sindbis infectivity is more a function of the host cell used in titering the virus rather than the cell line used to produce the virus, (2) the number of total and infectious particles produced is cell line dependent, and (3) the infectivity of released virus particles improves during the course of infection in both cells that have cytolytic infections and persistent infections. PMID:22484152

Sokoloski, Kevin J; Hayes, Chelsea A; Dunn, Megan P; Balke, Jennifer L; Hardy, Richard W; Mukhopadhyay, Suchetana

2012-07-01

223

Hepatitis C virus infection and mixed cryoglobulinemia: a striking association  

Microsoft Academic Search

Summary  The high frequency of liver involvement in cryoglobulinemia is well established. Although both etiology and pathogenesis have\\u000a remained so far undefined, recent studies suggest an association of mixed cryoglobulinemia with hepatitis C virus infection.\\u000a To explore this hypothesis further, we assessed the prevalence of hepatitis C virus antibodies and RNA in a large group of\\u000a patients, including: (1) 35 patients

Franco Dammacco; Domenico Sansonno; Vito Cornacchiulo; Carmela Mennuni; Raffaella Carbone; Gianfranco Lauletta; Anna Rina Iacobelli; Rita Rizzi

1993-01-01

224

Human Muscle Satellite Cells as Targets of Chikungunya Virus Infection  

Microsoft Academic Search

Background. Chikungunya (CHIK) virus is a mosquito-transmitted alphavirus that causes in humans an acute infection characterised by fever, polyarthralgia, head-ache, and myalgia. Since 2005, the emergence of CHIK virus was associated with an unprecedented magnitude outbreak of CHIK disease in the Indian Ocean. Clinically, this outbreak was characterized by invalidating poly-arthralgia, with myalgia being reported in 97.7% of cases. Since

Simona Ozden; Michel Huerre; Jean-Pierre Riviere; Lark L. Coffey; Philippe V. Afonso; Vincent Mouly; Jean de Monredon; Jean-Christophe Roger; Mohamed El Amrani; Jean-Luc Yvin; Marie-Christine Jaffar; Marie-Pascale Frenkiel; Marion Sourisseau; Olivier Schwartz; Gillian Butler-Browne; Philippe Desprès; Antoine Gessain; Pierre-Emmanuel Ceccaldi

2007-01-01

225

Neutralizing antibodies in Borna disease virus-infected rats.  

PubMed Central

Borna disease is a neurologic syndrome caused by infection with a nonsegmented, negative-strand RNA virus, Borna disease virus. Infected animals have antibodies to two soluble viral proteins, p40 and p23, and a membrane-associated viral glycoprotein, gp18. We examined the time course for the development of neutralization activity and the expression of antibodies to individual viral proteins in sera of infected rats. The appearance of neutralizing activity correlated with the development of immunoreactivity to gp18, but not p40 or p23. Monospecific and monoclonal antibodies to native gp18 and recombinant nonglycosylated gp18 were also found to have neutralizing activity and to immunoprecipitate viral particles or subparticles. These findings suggest that gp18 is likely to be present on the surface of the viral particles and is likely to contain epitopes important for virus neutralization.

Hatalski, C G; Kliche, S; Stitz, L; Lipkin, W I

1995-01-01

226

Mitochondrial dysfunction in rabies virus infection of neurons.  

PubMed

Infection with the challenge virus standard-11 (CVS) strain of fixed rabies virus induces neuronal process degeneration in adult mice after hindlimb footpad inoculation. CVS-induced axonal swellings of primary rodent dorsal root ganglion neurons are associated with 4-hydroxy-2-nonenal protein adduct staining, indicating a critical role of oxidative stress. Mitochondrial dysfunction is the major cause of oxidative stress. We hypothesized that CVS infection induces mitochondrial dysfunction leading to oxidative stress. We investigated the effects of CVS infection on several mitochondrial parameters in different cell types. CVS infection significantly increased maximal uncoupled respiration and complex IV respiration and complex I and complex IV activities, but did not affect complex II-III or citrate synthase activities. Increases in complex I activity, but not complex IV activity, correlated with susceptibility of the cells to CVS infection. CVS infection maintained coupled respiration and rate of proton leak, indicating a tight mitochondrial coupling. Possibly as a result of enhanced complex activity and efficient coupling, a high mitochondrial membrane potential was generated. CVS infection reduced the intracellular ATP level and altered the cellular redox state as indicated by a high NADH/NAD+ ratio. The basal production of reactive oxygen species (ROS) was not affected in CVS-infected neurons. However, a higher rate of ROS generation occurred in CVS-infected neurons in the presence of mitochondrial substrates and inhibitors. We conclude that CVS infection induces mitochondrial dysfunction leading to ROS overgeneration and oxidative stress. PMID:24277436

Alandijany, Thamir; Kammouni, Wafa; Roy Chowdhury, Subir K; Fernyhough, Paul; Jackson, Alan C

2013-12-01

227

Marburg virus infection detected in a common African bat.  

PubMed

Marburg and Ebola viruses can cause large hemorrhagic fever (HF) outbreaks with high case fatality (80-90%) in human and great apes. Identification of the natural reservoir of these viruses is one of the most important topics in this field and a fundamental key to understanding their natural history. Despite the discovery of this virus family almost 40 years ago, the search for the natural reservoir of these lethal pathogens remains an enigma despite numerous ecological studies. Here, we report the discovery of Marburg virus in a common species of fruit bat (Rousettus aegyptiacus) in Gabon as shown by finding virus-specific RNA and IgG antibody in individual bats. These Marburg virus positive bats represent the first naturally infected non-primate animals identified. Furthermore, this is the first report of Marburg virus being present in this area of Africa, thus extending the known range of the virus. These data imply that more areas are at risk for MHF outbreaks than previously realized and correspond well with a recently published report in which three species of fruit bats were demonstrated to be likely reservoirs for Ebola virus. PMID:17712412

Towner, Jonathan S; Pourrut, Xavier; Albariño, César G; Nkogue, Chimène Nze; Bird, Brian H; Grard, Gilda; Ksiazek, Thomas G; Gonzalez, Jean-Paul; Nichol, Stuart T; Leroy, Eric M

2007-01-01

228

Detection and diagnosis of rice-infecting viruses.  

PubMed

Rice-infecting viruses have caused serious damage to rice production in Asian, American, and African countries, where about 30 rice viruses and diseases have been reported. To control these diseases, developing accurate, quick methods to detect and diagnose the viruses in the host plants and any insect vectors of the viruses is very important. Based on an antigen-antibody reaction, serological methods such as latex agglutination reaction and enzyme-linked immunosorbent assay have advanced to detect viral particles or major proteins derived from viruses. They aid in forecasting disease and surveying disease spread and are widely used for virus detection at plant protection stations and research laboratories. From the early 2000s, based on sequence information for the target virus, several other methods such as reverse transcription-polymerase chain reaction (RT-PCR) and reverse transcription-loop-mediated isothermal amplification have been developed that are sensitive, rapid, and able to differentiate closely related viruses. Recent techniques such as real-time RT-PCR can be used to quantify the pathogen in target samples and monitor population dynamics of a virus, and metagenomic analyses using next-generation sequencing and microarrays show potential for use in the diagnosis of rice diseases. PMID:24130554

Uehara-Ichiki, Tamaki; Shiba, Takuya; Matsukura, Keiichiro; Ueno, Takanori; Hirae, Masahiro; Sasaya, Takahide

2013-01-01

229

Plasmacytoid dendritic cells sense hepatitis C virus-infected cells, produce interferon, and inhibit infection.  

PubMed

Hepatitis C virus (HCV), a member of the Flaviviridae family, is a single-stranded positive-sense RNA virus that infects >170 million people worldwide and causes acute and chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Despite its ability to block the innate host response in infected hepatocyte cell lines in vitro, HCV induces a strong type 1 interferon (IFN) response in the infected liver. The source of IFN in vivo and how it is induced are currently undefined. Here we report that HCV-infected cells trigger a robust IFN response in plasmacytoid dendritic cells (pDCs) by a mechanism that requires active viral replication, direct cell-cell contact, and Toll-like receptor 7 signaling, and we show that the activated pDC supernatant inhibits HCV infection in an IFN receptor-dependent manner. Importantly, the same events are triggered by HCV subgenomic replicon cells but not by free virus particles, suggesting the existence of a novel cell-cell RNA transfer process whereby HCV-infected cells can activate pDCs to produce IFN without infecting them. These results may explain how HCV induces IFN production in the liver, and they reveal a heretofore unsuspected aspect of the innate host response to viruses that can subvert the classical sensing machinery in the cells they infect, and do not infect or directly activate pDCs. PMID:20231459

Takahashi, Ken; Asabe, Shinichi; Wieland, Stefan; Garaigorta, Urtzi; Gastaminza, Pablo; Isogawa, Masanori; Chisari, Francis V

2010-04-20

230

Plasmacytoid dendritic cells sense hepatitis C virus-infected cells, produce interferon, and inhibit infection  

PubMed Central

Hepatitis C virus (HCV), a member of the Flaviviridae family, is a single-stranded positive-sense RNA virus that infects >170 million people worldwide and causes acute and chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Despite its ability to block the innate host response in infected hepatocyte cell lines in vitro, HCV induces a strong type 1 interferon (IFN) response in the infected liver. The source of IFN in vivo and how it is induced are currently undefined. Here we report that HCV-infected cells trigger a robust IFN response in plasmacytoid dendritic cells (pDCs) by a mechanism that requires active viral replication, direct cell-cell contact, and Toll-like receptor 7 signaling, and we show that the activated pDC supernatant inhibits HCV infection in an IFN receptor-dependent manner. Importantly, the same events are triggered by HCV subgenomic replicon cells but not by free virus particles, suggesting the existence of a novel cell-cell RNA transfer process whereby HCV-infected cells can activate pDCs to produce IFN without infecting them. These results may explain how HCV induces IFN production in the liver, and they reveal a heretofore unsuspected aspect of the innate host response to viruses that can subvert the classical sensing machinery in the cells they infect, and do not infect or directly activate pDCs.

Takahashi, Ken; Asabe, Shinichi; Wieland, Stefan; Garaigorta, Urtzi; Gastaminza, Pablo; Isogawa, Masanori; Chisari, Francis V.

2010-01-01

231

African swine fever virus infection in Ornithodoros ticks.  

PubMed

African swine fever virus (ASFV) is an arbovirus which is vectored by soft ticks of the Ornithodoros spp. and in the sylvatic cycle infects wart hogs and bush pigs. ASFV infection of domestic swine causes a high mortality disease. On the other hand, ASFV infection of the tick can result in a high-titered and persistent infection depending upon the ASFV isolate and the tick combination. Recently, morphological, classical virology (titration) and recombinant ASFV have been used to study the cellular, molecular and genetic interactions that occur between ASFV and its host tick. PMID:23085123

Burrage, Thomas G

2013-04-01

232

Functional NK cell cytotoxicity assays against virus infected cells.  

PubMed

Natural Killer (NK) cells are crucial to the control of many viral infections. They are able to kill infected cells directly through the secretion of cytotoxic granules or through binding to death receptors on target cells. They also secrete cytokines and chemokines and, through interactions with dendritic cells, can shape adaptive immunity. The activity of NK cells can be controlled by a balance of activating and inhibitory signals conveyed through ligands on target cells binding to receptors on the NK cell. As a result viruses have devised mechanisms to modulate the expression of NK ligands on target cells, interfering with NK cell recognition and prolonging the life of infected cells. An understanding of how viruses modulate the NK response can lead to an understanding both of NK cell function, and of virus pathogenesis. Measuring the ability of NK cells to kill target cells infected with different viruses, or expressing different viral proteins, is an invaluable technique to identify the proteins and mechanisms by which viruses modulate the NK response. Here we describe two methods to measure this; one method measures sodium dichromate (51)Cr that is released from target cells as they are killed, and the other uses 7-amino-actinomycin D (7-AAD) to measure apoptosis and death of target cells following incubation with NK cells. PMID:23996265

Aicheler, Rebecca J; Stanton, Richard J

2013-01-01

233

Plasticity and virus specificity of the airway epithelial cell immune response during respiratory virus infection.  

PubMed

Airway epithelial cells (AECs) provide the first line of defense in the respiratory tract and are the main target of respiratory viruses. Here, using oligonucleotide and protein arrays, we analyze the infection of primary polarized human AEC cultures with influenza virus and respiratory syncytial virus (RSV), and we show that the immune response of AECs is quantitatively and qualitatively virus specific. Differentially expressed genes (DEGs) specifically induced by influenza virus and not by RSV included those encoding interferon B1 (IFN-B1), type III interferons (interleukin 28A [IL-28A], IL-28B, and IL-29), interleukins (IL-6, IL-1A, IL-1B, IL-23A, IL-17C, and IL-32), and chemokines (CCL2, CCL8, and CXCL5). Lack of type I interferon or STAT1 signaling decreased the expression and secretion of cytokines and chemokines by the airway epithelium. We also observed strong basolateral polarization of the secretion of cytokines and chemokines by human and murine AECs during infection. Importantly, the antiviral response of human AECs to influenza virus or to RSV correlated with the infection signature obtained from peripheral blood mononuclear cells (PBMCs) isolated from patients with acute influenza or RSV bronchiolitis, respectively. IFI27 (also known as ISG12) was identified as a biomarker of respiratory virus infection in both AECs and PBMCs. In addition, the extent of the transcriptional perturbation in PBMCs correlated with the clinical disease severity. Our results demonstrate that the human airway epithelium mounts virus-specific immune responses that are likely to determine the subsequent systemic immune responses and suggest that the absence of epithelial immune mediators after RSV infection may contribute to explaining the inadequacy of systemic immunity to the virus. PMID:22398282

Ioannidis, Ioannis; McNally, Beth; Willette, Meredith; Peeples, Mark E; Chaussabel, Damien; Durbin, Joan E; Ramilo, Octavio; Mejias, Asuncion; Flaño, Emilio

2012-05-01

234

Cowpea viruses: effect of single and mixed infections on symptomatology and virus concentration.  

PubMed

Natural multiple viral infections of cultivated cowpeas have been reported in Nigeria. In this study, three Nigerian commercial cowpea cultivars ("Olo 11", "Oloyin" and "White") and two lines from the IITA (IT86D- 719 and TVU 76) were mechanically inoculated with Cowpea aphid-borne mosaic virus (CABMV), Bean southern mosaic virus (SBMV) and Cowpea mottle virus (CMeV) singly, as well as in all possible combinations at 10, 20 and 30 days after planting (DAP). Samples of leaves or stems were collected at 10, 20 and 30 days after inoculation (DAI) and analyzed for relative virus concentration by Enzyme-Linked Immunosrbent Assay. All the cultivars and lines {CVS/L} were susceptible to the viruses but the commercial CVS showed more severe symptoms and had relatively higher viral concentration. In single virus infections, CABMV which induced the most severe symptoms had absorbance values (at 405 nm) of 0.11 to 0.46 while SBMV and CMeV which induced moderate symptoms had virus titre of 0.74 to 1.99 and 0.11 to 0.90 respectively. Plants inoculated 10 DAP had significantly higher virus concentration than those inoculated 30 DAP. In mixed infections involving CABMV (10 DAP) apical necrosis and death were observed in commercial cultivars "Olo 11" and "White". Enhancement of CMeV titers were observed in plants infected with CMeV + CABMV. Multiple viral infections of cowpeas may result in complete yield loss, hence, the availability of seeds of cultivars with a high level of multiple virus resistance is recommended as a means of control. PMID:17900355

Taiwo, Moni A; Kareem, Kehinde T; Nsa, Imade Y; D'A Hughes, Jackies

2007-01-01

235

Pathogenesis of Modoc Virus (Flaviviridae; Flavivirus) in Persistently Infected Hamsters  

PubMed Central

The long-term persistence of Modoc virus (MODV) infection was investigated in a hamster model. Golden hamsters (Mesocricetus auratus) were infected by subcutaneous inoculation with MODV, in which fatal encephalitis developed in 12.5% (2 of 16). Surviving hamsters shed infectious MODV in their urine during the first five months after infection, and infectious MODV was recovered by co-cultivation of kidney tissue up to eight months after infection. There were no histopathologic changes observed in the kidneys despite detection of viral antigen for 250 days after infection. Mild inflammation and neuronal degeneration in the central nervous system were the primary lesions observed during early infection. These findings confirm previous reports of persistent flavivirus infection in animals and suggest a mechanism for the maintenance of MODV in nature.

Adams, A. Paige; Travassos da Rosa, Amelia P. A.; Nunes, Marcio R.; Xiao, Shu-Yuan; Tesh, Robert B.

2013-01-01

236

Herpes Simplex Virus 2 Infection Impacts Stress Granule Accumulation  

PubMed Central

Interference with stress granule (SG) accumulation is gaining increased appreciation as a common strategy used by diverse viruses to facilitate their replication and to cope with translational arrest. Here, we examined the impact of infection by herpes simplex virus 2 (HSV-2) on SG accumulation by monitoring the localization of the SG components T cell internal antigen 1 (TIA-1), Ras-GTPase-activating SH3-domain-binding protein (G3BP), and poly(A)-binding protein (PABP). Our results indicate that SGs do not accumulate in HSV-2-infected cells and that HSV-2 can interfere with arsenite-induced SG accumulation early after infection. Surprisingly, SG accumulation was inhibited despite increased phosphorylation of eukaryotic translation initiation factor 2? (eIF2?), implying that HSV-2 encodes previously unrecognized activities designed to maintain translation initiation downstream of eIF2?. SG accumulation was not inhibited in HSV-2-infected cells treated with pateamine A, an inducer that works independently of eIF2? phosphorylation. The SGs that accumulated following pateamine A treatment of infected cells contained G3BP and PABP but were largely devoid of TIA-1. We also identified novel nuclear structures containing TIA-1 that form late in infection. These structures contain the RNA binding protein 68-kDa Src-associated in mitosis (Sam68) and were noticeably absent in infected cells treated with inhibitors of viral DNA replication, suggesting that they arise as a result of late events in the virus replicative cycle.

Finnen, Renee L.; Pangka, Kyle R.

2012-01-01

237

Insights into Head-Tailed Viruses Infecting Extremely Halophilic Archaea  

PubMed Central

Extremophilic archaea, both hyperthermophiles and halophiles, dominate in habitats where rather harsh conditions are encountered. Like all other organisms, archaeal cells are susceptible to viral infections, and to date, about 100 archaeal viruses have been described. Among them, there are extraordinary virion morphologies as well as the common head-tailed viruses. Although approximately half of the isolated archaeal viruses belong to the latter group, no three-dimensional virion structures of these head-tailed viruses are available. Thus, rigorous comparisons with bacteriophages are not yet warranted. In the present study, we determined the genome sequences of two of such viruses of halophiles and solved their capsid structures by cryo-electron microscopy and three-dimensional image reconstruction. We show that these viruses are inactivated, yet remain intact, at low salinity and that their infectivity is regained when high salinity is restored. This enabled us to determine their three-dimensional capsid structures at low salinity to a ?10-Å resolution. The genetic and structural data showed that both viruses belong to the same T-number class, but one of them has enlarged its capsid to accommodate a larger genome than typically associated with a T=7 capsid by inserting an additional protein into the capsid lattice.

Pietila, Maija K.; Laurinmaki, Pasi; Russell, Daniel A.; Ko, Ching-Chung; Jacobs-Sera, Deborah; Butcher, Sarah J.

2013-01-01

238

Alveolar Macrophages Regulate the Induction of Primary Cytotoxic T-Lymphocyte Responses during Influenza Virus Infection  

Microsoft Academic Search

Virus-specific cytotoxic T lymphocytes (CTL) are thought to be responsible for the eradication of respiratory influenza virus infections by direct cytolysis of virus-infected epithelial cells. In this study, we provide evidence for a role for alveolar macrophages (AM) in the regulation of pulmonary virus-specific CTL responses. Prior to infection with influenza virus, AM were selectively eliminated in vivo with a

ODILIA L. C. WIJBURG; SEBASTIAN DINATALE; JIM VADOLAS; NICO VAN ROOIJEN; RICHARD A. STRUGNELL

1997-01-01

239

Screening for Hepatitis B Virus Infection in Nonpregnant Adolescents and Adults  

MedlinePLUS

... Screening for Hepatitis B Virus Infection in Nonpregnant Adolescents and Adults The U.S. Preventive Services Task Force ( ... Screening for Hepatitis B Virus Infection in Nonpregnant Adolescents and Adults. This final recommendation statement applies only ...

240

Tahyna virus genetics, infectivity, and immunogenicity in mice and monkeys  

PubMed Central

Background Tahyna virus (TAHV) is a human pathogen of the California encephalitis virus (CEV) serogroup (Bunyaviridae) endemic to Europe, Asia, and Africa. TAHV maintains an enzootic life cycle with several species of mosquito vectors and hares, rabbits, hedgehogs, and rodents serving as small mammal amplifying hosts. Human TAHV infection occurs in summer and early fall with symptoms of fever, headache, malaise, conjunctivitis, pharyngitis, and nausea. TAHV disease can progress to CNS involvement, although unlike related La Crosse virus (LACV), fatalities have not been reported. Human infections are frequent with neutralizing antibodies present in 60-80% of the elderly population in endemic areas. Results In order to determine the genomic sequence of wild-type TAHV, we chose three TAHV isolates collected over a 26-year period from mosquitoes. Here we present the first complete sequence of the TAHV S, M, and L segments. The three TAHV isolates maintained a highly conserved genome with both nucleotide and amino acid sequence identity greater than 99%. In order to determine the extent of genetic relatedness to other members of the CEV serogroup, we compared protein sequences of TAHV with LACV, Snowshoe Hare virus (SSHV), Jamestown Canyon virus (JCV), and Inkoo virus (INKV). By amino acid comparison, TAHV was most similar to SSHV followed by LACV, JCV, and INKV. The sequence of the GN protein is most conserved followed by L, N, GC, NSS, and NSM. In a weanling Swiss Webster mouse model, all three TAHV isolates were uniformly neurovirulent, but only one virus was neuroinvasive. In rhesus monkeys, the virus was highly immunogenic even in the absence of viremia. Cross neutralization studies utilizing monkey immune serum demonstrated that TAHV is antigenically distinct from North American viruses LACV and JCV. Conclusions Here we report the first complete sequence of TAHV and present genetic analysis of new-world viruses, LACV, SSHV, and JCV with old-world viruses, TAHV and INKV. Using immune serum generated in monkeys against TAHV, LACV, and JCV, we have demonstrated cross-neutralization within the CEV serogroup. Such cross reactivity may complicate virus identification, especially following JCV infection which elicited antibodies that cross neutralized both LACV and TAHV. These data also suggest that a single vaccine could generate a cross-neutralizing antibody response which may provide protection against CEV serogroup viruses from a wide geographic range.

2011-01-01

241

Determination of Baylisascaris schroederi Infection in Wild Giant Pandas by an Accurate and Sensitive PCR/CE-SSCP Method  

PubMed Central

It has been recognized that other than habitat loss, degradation and fragmentation, the infection of the roundworm Baylisascaris schroederi (B. schroederi) is one of the major causes of death in wild giant pandas. However, the prevalence and intensity of the parasite infection has been inconsistently reported through a method that uses sedimentation-floatation followed by a microscope examination. This method fails to accurately determine infection because there are many bamboo residues and/or few B. schroederi eggs in the examined fecal samples. In the present study, we adopted a method that uses PCR and capillary electrophoresis combined with a single-strand conformation polymorphism analysis (PCR/CE-SSCP) to detect B. schroederi infection in wild giant pandas at a nature reserve, and compared it to the traditional microscope approach. The PCR specifically amplified a single band of 279-bp from both fecal samples and positive controls, which was confirmed by sequence analysis to correspond to the mitochondrial COII gene of B. schroederi. Moreover, it was demonstrated that the amount of genomic DNA was linearly correlated with the peak area of the CE-SSCP analysis. Thus, our adopted method can reliably detect the infectious prevalence and intensity of B. schroederi in wild giant pandas. The prevalence of B. schroederi was found to be 54% in the 91 fecal samples examined, and 48% in the fecal samples of 31 identified individual giant pandas. Infectious intensities of the 91 fecal samples were detected to range from 2.8 to 959.2 units/gram, and from 4.8 to 959.2 units/gram in the fecal samples of the 31 identified giant pandas. For comparison, by using the traditional microscope method, the prevalence of B. schroederi was found to be only 33% in the 91 fecal samples, 32% in the fecal samples of the 31 identified giant pandas, and no reliable infectious intensity was observed.

Zhang, Wenping; Yie, Shangmian; Yue, Bisong; Zhou, Jielong; An, Renxiong; Yang, Jiangdong; Chen, Wangli; Wang, Chengdong; Zhang, Liang; Shen, Fujun; Yang, Guangyou; Hou, Rong; Zhang, Zhihe

2012-01-01

242

Adaptive immune response during hepatitis C virus infection.  

PubMed

Hepatitis C virus (HCV) infection affects about 170 million people worldwide and it is a major cause of liver cirrhosis and hepatocellular carcinoma. HCV is a hepatotropic non-cytopathic virus able to persist in a great percentage of infected hosts due to its ability to escape from the immune control. Liver damage and disease progression during HCV infection are driven by both viral and host factors. Specifically, adaptive immune response carries out an essential task in controlling non-cytopathic viruses because of its ability to recognize infected cells and to destroy them by cytopathic mechanisms and to eliminate the virus by non-cytolytic machinery. HCV is able to impair this response by several means such as developing escape mutations in neutralizing antibodies and in T cell receptor viral epitope recognition sites and inducing HCV-specific cytotoxic T cell anergy and deletion. To impair HCV-specific T cell reactivity, HCV affects effector T cell regulation by modulating T helper and Treg response and by impairing the balance between positive and negative co-stimulatory molecules and between pro- and anti-apoptotic proteins. In this review, the role of adaptive immune response in controlling HCV infection and the HCV mechanisms to evade this response are reviewed. PMID:24707125

Larrubia, Juan Ramón; Moreno-Cubero, Elia; Lokhande, Megha Uttam; García-Garzón, Silvia; Lázaro, Alicia; Miquel, Joaquín; Perna, Cristian; Sanz-de-Villalobos, Eduardo

2014-04-01

243

Tranylcypromine reduces herpes simplex virus 1 infection in mice.  

PubMed

Herpes simplex virus 1 (HSV-1) infects the majority of the human population and establishes latency by maintaining viral genomes in neurons of sensory ganglia. Latent virus can undergo reactivation to cause recurrent infection. Both primary and recurrent infections can cause devastating diseases, including encephalitis and corneal blindness. Acyclovir is used to treat patients, but virus resistance to acyclovir is frequently reported. Recent in vitro findings reveal that pretreatment of cells with tranylcypromine (TCP), a drug widely used in the clinic to treat neurological disorders, restrains HSV-1 gene transcription by inhibiting the histone-modifying enzyme lysine-specific demethylase 1. The present study was designed to examine the anti-HSV-1 efficacy of TCP in vivo because of the paucity of reports on this issue. Using the murine model, we found that TCP decreased the severity of wild-type-virus-induced encephalitis and corneal blindness, infection with the acyclovir-resistant (thymidine kinase-negative) HSV-1 mutant, and tissue viral loads. Additionally, TCP blocked in vivo viral reactivation in trigeminal ganglia. These results support the therapeutic potential of TCP for controlling HSV-1 infection. PMID:24590478

Yao, Hui-Wen; Lin, Pin-Hung; Shen, Fang-Hsiu; Perng, Guey-Chuen; Tung, Yuk-Ying; Hsu, Sheng-Min; Chen, Shun-Hua

2014-05-01

244

Adaptive immune response during hepatitis C virus infection  

PubMed Central

Hepatitis C virus (HCV) infection affects about 170 million people worldwide and it is a major cause of liver cirrhosis and hepatocellular carcinoma. HCV is a hepatotropic non-cytopathic virus able to persist in a great percentage of infected hosts due to its ability to escape from the immune control. Liver damage and disease progression during HCV infection are driven by both viral and host factors. Specifically, adaptive immune response carries out an essential task in controlling non-cytopathic viruses because of its ability to recognize infected cells and to destroy them by cytopathic mechanisms and to eliminate the virus by non-cytolytic machinery. HCV is able to impair this response by several means such as developing escape mutations in neutralizing antibodies and in T cell receptor viral epitope recognition sites and inducing HCV-specific cytotoxic T cell anergy and deletion. To impair HCV-specific T cell reactivity, HCV affects effector T cell regulation by modulating T helper and Treg response and by impairing the balance between positive and negative co-stimulatory molecules and between pro- and anti-apoptotic proteins. In this review, the role of adaptive immune response in controlling HCV infection and the HCV mechanisms to evade this response are reviewed.

Larrubia, Juan Ramon; Moreno-Cubero, Elia; Lokhande, Megha Uttam; Garcia-Garzon, Silvia; Lazaro, Alicia; Miquel, Joaquin; Perna, Cristian; Sanz-de-Villalobos, Eduardo

2014-01-01

245

Negative-strand RNA viruses: the plant-infecting counterparts.  

PubMed

While a large number of negative-strand (-)RNA viruses infect animals and humans, a relative small number have plants as their primary host. Some of these have been classified within families together with animal/human infecting viruses due to similarities in particle morphology and genome organization, while others have just recently been/or are still classified in floating genera. In most cases, at least two striking differences can still be discerned between the animal/human-infecting viruses and their plant-infecting counterparts which for the latter relate to their adaptation to plants as hosts. The first one is the capacity to modify plasmodesmata to facilitate systemic spread of infectious viral entities throughout the plant host. The second one is the capacity to counteract RNA interference (RNAi, also referred to as RNA silencing), the innate antiviral defence system of plants and insects. In this review an overview will be presented on the negative-strand RNA plant viruses classified within the families Bunyaviridae, Rhabdoviridae, Ophioviridae and floating genera Tenuivirus and Varicosavirus. Genetic differences with the animal-infecting counterparts and their evolutionary descendants will be described in light of the above processes. PMID:21963660

Kormelink, Richard; Garcia, Maria Laura; Goodin, Michael; Sasaya, Takahide; Haenni, Anne-Lise

2011-12-01

246

Giant DNA Virus Mimivirus Encodes Pathway for Biosynthesis of Unusual Sugar 4-Amino-4,6-dideoxy-d-glucose (Viosamine)*  

PubMed Central

Mimivirus is one the largest DNA virus identified so far, infecting several Acanthamoeba species. Analysis of its genome revealed the presence of a nine-gene cluster containing genes potentially involved in glycan formation. All of these genes are co-expressed at late stages of infection, suggesting their role in the formation of the long fibers covering the viral surface. Among them, we identified the L136 gene as a pyridoxal phosphate-dependent sugar aminotransferase. This enzyme was shown to catalyze the formation of UDP-4-amino-4,6-dideoxy-d-glucose (UDP-viosamine) from UDP-4-keto-6-deoxy-d-glucose, a key compound involved also in the biosynthesis of l-rhamnose. This finding further supports the hypothesis that Mimivirus encodes a glycosylation system that is completely independent of the amoebal host. Viosamine, together with rhamnose, (N-acetyl)glucosamine, and glucose, was found as a major component of the viral glycans. Most of the sugars were associated with the fibers, confirming a capsular-like nature of the viral surface. Phylogenetic analysis clearly indicated that L136 was not a recent acquisition from bacteria through horizontal gene transfer, but it was acquired very early during evolution. Implications for the origin of the glycosylation machinery in giant DNA virus are also discussed.

Piacente, Francesco; Marin, Margherita; Molinaro, Antonio; De Castro, Cristina; Seltzer, Virginie; Salis, Annalisa; Damonte, Gianluca; Bernardi, Cinzia; Claverie, Jean-Michel; Abergel, Chantal; Tonetti, Michela

2012-01-01

247

A primate model of respiratory syncytial virus infection.  

PubMed

To determine whether bonnet monkeys are susceptible to infection and disease due to respiratory syncytial virus (RSV), 4 juvenile bonnet monkeys (Macaca radiata) were inoculated with RSV intratracheally and sacrificed at 3, 5, 7 and 9 days post infection. RSV was cultured from pre-autopsy broncheoalveolar lavage fluid from all 4 animals with a peak titre of virus on day 9. Serum RSV neutralizing antibody was present by day 7. Animals developed tachypnoea and chest retractions by 5th day post infection and 2 animals had lobular pneumonia on chest radiography. The pathological changes were of a bronchovascular inflammation, interstitial pneumonia and alveolitis, akin to that seen in humans. These findings show that bonnet monkeys can be infected with RSV, and can develop immune response and clinical and pathological changes similar to those seen in human infants with RSV disease. Thus intractracheal RSV inoculation of juvenile bonnet monkeys appears to be a good model to study pathogenesis of RSV disease. PMID:9838875

Babu, P G; Selvan, A; Christuraj, S; David, J; John, T J; Simoes, E A

1998-08-01

248

Herpes simplex virus 1 infection on a reconstructive free flap.  

PubMed

Objective: Herpes simplex virus 1 (HSV1) is a widespread virus that primarily causes orofacial infection. Methods: We present a case of HSV1 infection on a free radial forearm flap used to reconstruct a palate defect. Initially, the free flap appeared healthy; however, after 48 hours the free flap appeared in distress, with dark red colour and fast capillary refill. Venous congestion was suspected, and the patient underwent a second operation where no vascular compromise was found. Vesicles were noted on the free flap; swabs revealed HSV1 infection. Results: Complete recovery of the free flap was achieved with acyclovir. Discussion: To the best of our knowledge, this is the first report of HSV1 infection on a free flap that was found to be responsible for the free flap appearing distressed. PMID:23837109

Parys, Simon P; Leman, Thea; Gurfinkel, Reuven

2013-01-01

249

Diagnosis of Hepatitis A Virus Infection: a Molecular Approach  

PubMed Central

Current serologic tests provide the foundation for diagnosis of hepatitis A and hepatitis A virus (HAV) infection. Recent advances in methods to identify and characterize nucleic acid markers of viral infections have provided the foundation for the field of molecular epidemiology and increased our knowledge of the molecular biology and epidemiology of HAV. Although HAV is primarily shed in feces, there is a strong viremic phase during infection which has allowed easy access to virus isolates and the use of molecular markers to determine their genetic relatedness. Molecular epidemiologic studies have provided new information on the types and extent of HAV infection and transmission in the United States. In addition, these new diagnostic methods have provided tools for the rapid detection of food-borne HAV transmission and identification of the potential source of the food contamination.

Nainan, Omana V.; Xia, Guoliang; Vaughan, Gilberto; Margolis, Harold S.

2006-01-01

250

Oral conditions associated with hepatitis C virus infection.  

PubMed

Hepatitis C virus (HCV) infection in more than 170 million chronically infected patients with no developed preventive vaccine is a globally important issue. In addition to expected hepatic manifestations, a number of extrahepatic manifestations, such as mixed cryoglobulinemia, glomerulonephritis, polyarteritis nodosa, rashes, renal disease, neuropathy, and lymphoma, have been reported following HCV infection, which are believed to be influenced by the virus or the host immune response. HCV combination therapy with pegylated interferon and ribavirin might be associated with side effects as well. The association of HCV with special oral conditions has also been reported recurrently; the mechanism of most of which remains unclear. This article reviews the association of HCV infection with some of the oral conditions such as oral health, Sjogren's syndrome, lichen planus and oral cancer. PMID:24195977

Alavian, Seyed-Moayed; Mahboobi, Nastaran; Mahboobi, Nima; Karayiannis, Peter

2013-01-01

251

Host Susceptibility to endogenous viruses: defective, glycoprotein-expressing proviruses interfere with infections.  

PubMed Central

Three defective endogenous avian leukosis viruses, ev3, ev6 and ev9, interfered with subgroup E virus infections, ev3, ev6, and ev9 expressed high levels of subgroup E envelope glycoproteins. These glycoproteins reduced the activity of cellular receptors for subgroup E viruses. ev3 and ev6 protected chickens and cultured cells from subgroup E virus infections.

Robinson, H L; Astrin, S M; Senior, A M; Salazar, F H

1981-01-01

252

Host Susceptibility to endogenous viruses: defective, glycoprotein-expressing proviruses interfere with infections.  

PubMed

Three defective endogenous avian leukosis viruses, ev3, ev6 and ev9, interfered with subgroup E virus infections, ev3, ev6, and ev9 expressed high levels of subgroup E envelope glycoproteins. These glycoproteins reduced the activity of cellular receptors for subgroup E viruses. ev3 and ev6 protected chickens and cultured cells from subgroup E virus infections. PMID:6275116

Robinson, H L; Astrin, S M; Senior, A M; Salazar, F H

1981-12-01

253

Virus-Neutralizing Activity Mediated by the Fab Fragment of a Hemagglutinin-Specific Antibody Is Sufficient for the Resolution of Influenza Virus Infection in SCID Mice  

Microsoft Academic Search

Antibodies (Abs) contribute to the control of influenza virus infection in vivo by reducing progeny virus yield from infected cells (yield reduction (YR)) and by inhibiting progeny virus from spreading the infection to new host cells (virus neutralization (VN)). Previous studies showed that the infection could be resolved in severe combined immunodeficiency (SCID) mice by treatment with hemagglutinin (HA)-specific monoclonal

Krystyna Mozdzanowska; Jingqi Feng; Walter Gerhard

2003-01-01

254

Therapy of experimental influenza virus infection with pyrrolidine dithiocarbamate  

Microsoft Academic Search

The search for new antiviral strategies to treat influenza A virus (IAV) infections is one major international health care\\u000a activity. Hereby, the IAV-caused misuse of cellular nuclear factor kappa B (NF-?B) signaling pathways in infected cells represents\\u000a one target for antiviral therapy. In the present study, pyrrolidine dithiocarbamate (PDTC), which is known as an antioxidant\\u000a and as an inhibitor of

Nadine Wiesener; Christin Zimmer; Nadine Jarasch-Althof; Peter Wutzler; Andreas Henke

2011-01-01

255

Restricted HEL-12 virus infections in de novo infected human and canine cells.  

PubMed

Model systems to study restricted primate retrovirus expression were established by de novo infection of canine foetal thymus cells (CF-2Th) and superinfection of HEL-12 cells with HEL-12 virus. In the resulting CF-2Th/HEL-12V cells and HEL-12/HEL-12V cells, four sequential stages of virus infection were defined by the production of reverse transcriptase (RT)-containing particles and expression of virus antigens as detected by radioimmunoassays. Stage 1 cells did not synthesize virus antigens or produce RT-containing particles. Stage 2 cells synthesized virus antigen but not RT-containing particles. Stage 3 cells synthesized antigen and produced RT-containing particles, and stage 4 cells synthesized virus antigens but no longer produced RT-containing particles. The duration of the four stage infection is 2 to 3 weeks in both cell types. Monospecific competition radioimmunoassays to detect HEL-12V p30 or gp70 antigen showed high levels of virus antigen throughout stages 2 to 4 of infection. Analysis of immunoprecipitates formed under conditions to detect either p30- or or gp70-containing proteins in cells pulsed and pulsed--chased with [3H]leucine showed the same spectrum of virus precursor polyproteins, intermediates and mature virion components in stage 2 to 4 cells in canine and human infections. Spent culture fluids collected from stage 3 and stage 4 CF-2Th/HEL-12V cells failed to reveal inhibitors of RT activity. Stage 4 CF-2Th/HEL-12V or HEL-12/HEL-12V cells labelled with [3H]uridine produced virions which incorporated [3H]uridine but did not have RT activity, suggesting that restricted infection is characterized by production of HEL-12V defective in RT activity. PMID:6172557

Black, R J; Yang, J W; Panem, S

1981-12-01

256

Innate immune responses in raccoons after raccoon rabies virus infection.  

PubMed

Zoonotic wildlife diseases pose significant health risks not only to their primary vectors but also to humans and domestic animals. Rabies is a lethal encephalitis caused by rabies virus (RV). This RNA virus can infect a range of terrestrial mammals but each viral variant persists in a particular reservoir host. Active management of these host vectors is needed to minimize the negative impacts of this disease, and an understanding of the immune response to RV infection aids strategies for host vaccination. Current knowledge of immune responses to RV infection comes primarily from rodent models in which an innate immune response triggers activation of several genes and signalling pathways. It is unclear, however, how well rodent models represent the immune response of natural hosts. This study investigates the innate immune response of a primary host, the raccoon, to a peripheral challenge using the raccoon rabies virus (RRV). The extent and temporal course of this response during RRV infection was analysed using genes predicted to be upregulated during infection (IFNs; IFN regulatory factors; IL-6; Toll like receptor-3; TNF receptor). We found that RRV activated components of the innate immune system, with changes in levels of transcripts correlated with presence of viral RNA. Our results suggest that natural reservoirs of rabies may not mimic the immune response triggered in rodent models, highlighting the need for further studies of infection in primary hosts. PMID:24085257

Srithayakumar, Vythegi; Sribalachandran, Hariharan; Rosatte, Rick; Nadin-Davis, Susan A; Kyle, Christopher J

2014-01-01

257

Intra-uterine and neonatal herpes simplex virus infection.  

PubMed

Herpes simplex viruses type 1 (buccal) and type 2 (genital) present a serious threat to neonates. Infection may occur in utero, by transplacental or ascending infection, by exposure to genital lesions during delivery, or postnatally from relatives or attendants. Antiviral drugs, vidarabine and acyclovir are of equal efficacy and toxicity when used in infants with herpes simplex infections. Transplacental infection during early pregnancy is a very rare cause of congenital abnormality but there have been no recommendations for intervention. Most neonatal infections are acquired from the mother during delivery. Antepartum screening for virus excretion is of no value in predicting exposure at delivery and should not be performed. Caesarean section should be reserved for women who have active lesions at delivery. Even if active lesions are present, in women with a history of recurrent herpes, the risks to the infant are low. Prophylactic acyclovir during pregnancy cannot be recommended until evidence of safety and efficacy has been obtained from controlled trials. Staff should be alert to the dangers of postnatal infection and measures should be taken to exclude, or reduce virus excretion from, staff members or visitors who have orolabial or cutaneous herpes lesions. PMID:1803497

Jeffries, D J

1991-01-01

258

Neutralizing Antibodies and Pathogenesis of Hepatitis C Virus Infection  

PubMed Central

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide. The interplay between the virus and host innate and adaptive immune responses determines the outcome of infection. There is increasing evidence that host neutralizing responses play a relevant role in the resulting pathogenesis. Furthermore, viral evasion from host neutralizing antibodies has been revealed to be an important contributor in leading both to viral persistence in acute liver graft infection following liver transplantation, and to chronic viral infection. The development of novel model systems to study HCV entry and neutralization has allowed a detailed understanding of the molecular mechanisms of virus-host interactions during antibody-mediated neutralization. The understanding of these mechanisms will ultimately contribute to the development of novel antiviral preventive strategies for liver graft infection and an urgently needed vaccine. This review summarizes recent concepts of the role of neutralizing antibodies in viral clearance and protection, and highlights consequences of viral escape from neutralizing antibodies in the pathogenesis of HCV infection.

Fafi-Kremer, Samira; Fauvelle, Catherine; Felmlee, Daniel J.; Zeisel, Mirjam B.; Lepiller, Quentin; Fofana, Isabel; Heydmann, Laura; Stoll-Keller, Francoise; Baumert, Thomas F.

2012-01-01

259

Handwashing and cohorting in prevention of hospital acquired infections with respiratory syncytial virus  

Microsoft Academic Search

Hospital acquired infections with respiratory syncytial virus are a major problem. The virus is spread predominantly by infected nasal secretions and we investigated whether we could reduce its incidence by cohorting babies on each ward into designated areas and encouraging staff and parents to wash their hands. We examined the incidence of hospital acquired infection due to respiratory syncytial virus

D Isaacs; H Dickson; C OCallaghan; R Sheaves; A Winter; E R Moxon

1991-01-01

260

Estimating the Impact of Vaccination on Acute Simian-Human Immunodeficiency Virus\\/Simian Immunodeficiency Virus Infections  

Microsoft Academic Search

The dynamics of HIV infection have been studied in humans and in a variety of animal models. The standard model of infection has been used to estimate the basic reproductive ratio of the virus, calculated from the growth rate of virus in acute infection. This method has not been useful in studying the effects of vaccination, since, for the vaccines

Janka Petravic; Ruy M. Ribeiro; Danilo R. Casimiro; Joseph J. Mattapallil; Mario Roederer; John W. Shiver; Miles P. Davenport

2008-01-01

261

Protective effect of fluvastatin on influenza virus infection.  

PubMed

Statins are 3?hydroxy?3?methylglutaryl coenzyme A reductase inhibitors and have pleiotropic effects. It has been suggested that statins may be a potential treatment during the next influenza pandemic. In a previous study we found that a statin/caffeine combination protects BALB/c mice against Influenza A, subtypes haemagglutinin type 5 and neuraminidase type 1 (H5N1), H3N2 and H1N1 infection. The effect of statins alone on influenza virus infection, however, is not known. In this study, it was investigated whether fluvastatin is capable of inhibiting influenza A virus replication in vitro. The results demonstrated that the synthesis of viral RNA and protein was affected by fluvastatin treatment. Virus production was markedly reduced when fluvastatin was administered simultaneously with the virus; however, a greater inhibition was observed when fluvastatin was added following viral adsorption. The selectivity index [SI; 50% cytotoxic concentration (CC50)/50% inhibition concentration (IC50)], however, was only 21. It was further demonstrated that fluvastatin protects host cells against influenza?induced inflammation by reducing the production of tumour necrosis factor??, interleukin 8 and interferon ?. In conclusion, the results demonstrated that fluvastatin exerted a minor inhibitory effect on influenza virus infection, which involved anti?inflammatory activities. PMID:24676773

Peng, Jing; Zhang, Dingmei; Ma, Yu; Wang, Guoling; Guo, Zhongmin; Lu, Jiahai

2014-06-01

262

Biological characterization of acute infection with ground squirrel hepatitis virus.  

PubMed Central

Ground squirrel hepatitis virus (GSHV) is a small DNA virus, structurally and antigenically related to the human hepatitis B virus, which occurs naturally among certain wild populations of ground squirrels (P. L. Marion et al., Proc. Natl. Acad. Sci. U.S.A. 77:2941-2945, 1980). Serum from naturally infected animals was used to transmit GSHV in the laboratory by parenteral inoculation of susceptible squirrels. Sixty percent of recipient animals developed viral surface antigenemia after a latent period of 2 to 3 months; three of these animals have remained viremic for over 9 months. Like hepatitis B virus, GSHV demonstrates marked hepatotropism, with viral DNA detected in significant quantities only in the liver, where an average of 6 X 10(2) to 6 X 10(3) viral DNA molecules per cell were found by molecular hybridization. However, histological signs of liver injury after acute infection are minimal. In contrast to infection of its natural host, parenteral administration of GSHV to rats, mice, guinea pigs, and hamsters did not result in demonstrable antigenemia, suggesting that the host range of GSHV, like that of hepatitis B virus, is narrow. Images

Ganem, D; Weiser, B; Barchuk, A; Brown, R J; Varmus, H E

1982-01-01

263

Epidemiology and natural history of hepatitis C virus infection  

PubMed Central

Hepatitis C virus (HCV) affects 130-210 million people worldwide and is one of the major risk factors for hepatocellular carcinoma. Globally, at least one third of hepatocellular carcinoma cases are attributed to HCV infection, and 350000 people died from HCV related diseases per year. There is a great geographical variation of HCV infection globally, with risk factors for the HCV infection differing in various countries. The progression of chronic hepatitis C to end-stage liver disease also varies in different study populations. A long-term follow-up cohort enrolling participants with asymptomatic HCV infection is essential for elucidating the natural history of HCV-caused hepatocellular carcinoma, and for exploring potential seromarkers that have high predictability for risk of hepatocellular carcinoma. However, prospective cohorts comprising individuals with HCV infection are still uncommon. The risk evaluation of viral load elevation and associated liver disease/cancer in HCV (REVEAL-HCV) study has followed a cohort of 1095 residents seropositive for antibodies against hepatitis C virus living in seven townships in Taiwan for more than fifteen years. Most of them have acquired HCV infection through iatrogenic transmission routes. As the participants in the REVEAL-HCV study rarely receive antiviral therapies, it provides a unique opportunity to study the natural history of chronic HCV infection. In this review, the prevalence, risk factors and natural history of HCV infection are comprehensively reviewed. The study cohort, data collection, and findings on liver disease progression of the REVEAL-HCV study are described.

Lee, Mei-Hsuan; Yang, Hwai-I; Yuan, Yong; L'Italien, Gilbert; Chen, Chien-Jen

2014-01-01

264

Tobacco mosaic virus and the study of early events in virus infections.  

PubMed Central

In order to establish infections, viruses must be delivered to the cells of potential hosts and must then engage in activities that enable their genomes to be expressed and replicated. With most viruses, the events that precede the onset of production of progeny virus particles are referred to as the early events and, in the case of positive-strand RNA viruses, they include the initial interaction with and entry of host cells and the release (uncoating) of the genome from the virus particles. Though the early events remain one of the more poorly understood areas of plant virology, the virus with which most of the relevant research has been performed is tobacco mosaic virus (TMV). In spite of this effort, there remains much uncertainty about the form or constituent of the virus that actually enters the initially invaded cell in a plant and about the mechanism(s) that trigger the subsequent uncoating (virion disassembly) reactions. A variety of approaches have been used in attempts to determine the fate of TMV particles that are involved in the establishment of an infection and these are briefly described in this review. In some recent work, it has been proposed that the uncoating process involves the bidirectional release of coat protein subunits from the viral RNA and that these activities may be mediated by cotranslational and coreplicational disassembly mechanisms.

Shaw, J G

1999-01-01

265

Characteristics of viruses derived from nude mice with persistent measles virus infection.  

PubMed

Measles virus (MV) isolates from patients with subacute sclerosing panencephalitis (SSPE) differ from wild-type MV virologically. However, few animal models have reported viruses with characteristics of the SSPE virus. The MV Edmonston strain was inoculated into the subarachnoid space of nude mice. All nude mice displayed weight loss and required euthanasia, with a mean survival duration of 73.2 days. The viral load in the brain was 4- to 400-fold higher than the inoculated load, and brain infection was confirmed by immunostaining. Gene sequencing of the viruses revealed that amino acid mutations occurred more frequently in matrix proteins. The most common mutation was a uridine-to-cytosine transition. The virus exhibited lower free virus particle formation ability than the Edmonston strain. When nude mice were challenged with 2 × 10(2) PFU of the brain-derived virus, the mean survival duration was 34.7 days, which was significantly shorter than that of the mice challenged with 4 × 10(4) PFU of the Edmonston strain (P < 0.01). This study indicated that MV in a nude mouse model of persistent infection exhibited characteristics of the SSPE virus. This model may prove useful in elucidating the pathogenic mechanism of SSPE and developing potential therapeutics. PMID:23345518

Abe, Yusaku; Hashimoto, Koichi; Watanabe, Masahiro; Ohara, Shinichiro; Sato, Masatoki; Kawasaki, Yukihiko; Hashimoto, Yuko; Hosoya, Mitsuaki

2013-04-01

266

Characteristics of Viruses Derived from Nude Mice with Persistent Measles Virus Infection  

PubMed Central

Measles virus (MV) isolates from patients with subacute sclerosing panencephalitis (SSPE) differ from wild-type MV virologically. However, few animal models have reported viruses with characteristics of the SSPE virus. The MV Edmonston strain was inoculated into the subarachnoid space of nude mice. All nude mice displayed weight loss and required euthanasia, with a mean survival duration of 73.2 days. The viral load in the brain was 4- to 400-fold higher than the inoculated load, and brain infection was confirmed by immunostaining. Gene sequencing of the viruses revealed that amino acid mutations occurred more frequently in matrix proteins. The most common mutation was a uridine-to-cytosine transition. The virus exhibited lower free virus particle formation ability than the Edmonston strain. When nude mice were challenged with 2 × 102 PFU of the brain-derived virus, the mean survival duration was 34.7 days, which was significantly shorter than that of the mice challenged with 4 × 104 PFU of the Edmonston strain (P < 0.01). This study indicated that MV in a nude mouse model of persistent infection exhibited characteristics of the SSPE virus. This model may prove useful in elucidating the pathogenic mechanism of SSPE and developing potential therapeutics.

Hashimoto, Koichi; Watanabe, Masahiro; Ohara, Shinichiro; Sato, Masatoki; Kawasaki, Yukihiko; Hashimoto, Yuko; Hosoya, Mitsuaki

2013-01-01

267

[Extrahepatic manifestations of hepatitis C virus infection].  

PubMed

HCV virus is associated with various immunological disorders. Some of them like mixed cryoglobulinemia, are proved by molecular biology and virology. Others are presumed auto-immune: auto-antibodies production (antinuclear, anti-smooth muscle, anti-liver-kidney microsomal antibodies...) has generally no pathological significance; however, true auto-immune diseases such as auto-immune hepatitis type 1 or 2, Sjögren's syndrome, lichen planus and auto-immune thyroiditis can be associated with HCV related liver disease. Finally, the association of some extra-hepatic manifestations like porphyria cutanea tarda with hepatitis C virus are only based on epidemiological data. Alpha interferon, the reference treatment of chronic hepatitis C, can be efficient on manifestations such as cryoglobulinemia which are directly linked to the virus. However, because of its immunological effect, the same treatment can severely worsen auto-immunological diseases associated with hepatitis C virus (autoimmune hepatitis, thyroiditis...). In practice, it's of great importance to identify and classify these extra-hepatic manifestations to optimize the treatment of chronic hepatitis C. PMID:10905094

Loustaud-Ratti, V; Lunel, F

2000-05-15

268

Vaccinia Virus Infection in Monkeys, Brazilian Amazon  

PubMed Central

To detect orthopoxvirus in the Brazilian Amazon, we conducted a serosurvey of 344 wild animals. Neutralizing antibodies against orthopoxvirus were detected by plaque-reduction neutralizing tests in 84 serum samples. Amplicons from 6 monkey samples were sequenced. These amplicons identified vaccinia virus genetically similar to strains from bovine vaccinia outbreaks in Brazil.

Abrahao, Jonatas S.; Silva-Fernandes, Andre T.; Lima, Larissa S.; Campos, Rafael K.; Guedes, Maria I.M.C.; Cota, Marcela M.G.; Assis, Felipe L.; Borges, Iara A.; Souza-Junior, Milton F.; Lobato, Zelia I.P.; Bonjardim, Claudio A.; Ferreira, Paulo C.P.; Trindade, Giliane S.

2010-01-01

269

Autoimmune disease complicating antiviral therapy for hepatitis C virus infection  

Microsoft Academic Search

Objective: To review autoimmune disease complicating therapy with type I interferons (IFNs), specifically in the setting of hepatitis C virus (HCV) infection. Methods: This study describes 13 reported cases of drug-induced systemic lupus erythematosus (SLE) associated with IFN therapy for the period reported during 1990-2002 by searching MEDLINE. In addition, 2 additional patients are presented, 1 with SLE and 1

Leslie E. Wilson; David Widman; Steven H. Dikman; Peter D. Gorevic

2002-01-01

270

Protection of potato virus X infection by plant extracts  

Microsoft Academic Search

Extracts from the roots ofBoerhaavia diffusa L., stems ofCuscuta reflexa Roxb. or leaves ofEuphorbia hirta L. have shown a potential protective effect on the infection of potato virus X, in hypersensitive and systemic hosts. The\\u000a inhibition by these extracts was systemic and sensitive to actinomycin D.

L. P. Awasthi; K. Mukerjee

1980-01-01

271

Clinical signs, diagnosis, and case reports of Vaccinia virus infections  

Microsoft Academic Search

Vaccinia virus is responsible for a zoonosis that usually affects cattle and human beings in Brazil. The initial clinical signs of the infection are focal red skin areas, fever, and general symptoms similar to those of a cold. Then, pustules and ulcerated lesions surrounded by edema and erythema follow, as well as local lymphadenopathy that can last for weeks. Cure

Daniela Carla Medeiros-Silva; Eduardo Augusto dos Santos Moreira-Silva; Juliana de Assis Silva Gomes; Flávio Guimarães da Fonseca; Rodrigo Correa-Oliveira

2010-01-01

272

Infectious bronchitis virus: Immunopathogenesis of infection in the chicken  

Microsoft Academic Search

The immunopathogenesis of infectious bronchitis virus (IBV) infection in the chicken is reviewed. While infectious bronchitis (IB) is considered primarily a disease of the respiratory system, different IBV strains may show variable tissue tropisms and also affect the oviduct and the kidneys, with serious consequences. Some strains replicate in the intestine but apparently without pathological changes. Pectoral myopathy has been

G. Dhinakar Raj; R. C. Jones

1997-01-01

273

SURVEILLANCE FOR ROSS RIVER VIRUS INFECTION USING BLOOD DONORS  

Microsoft Academic Search

The number of clinical Ross River virus (RRV) infections (epidemic polyarthritis) each year in Australia continues to grow despite extensive vector control programs. There is a need, therefore, for a surveillance program that can give sufficient warning of outbreaks of the disease so that highly focused preventative measures may be undertaken. The ability of a surveillance program, based on voluntary

JOHN G. AASKOV; JIAN-YING CHEN; NGUYEN T. H. HANH; PETA M. DENNINGTON

274

Dry weather induces outbreaks of human West Nile virus infections  

Microsoft Academic Search

BACKGROUND: Since its first occurrence in the New York City area during 1999, West Nile virus (WNV) has spread rapidly across North America and has become a major public health concern in North America. By 2002, WNV was reported in 40 states and the District of Columbia with 4,156 human and 14,539 equine cases of infection. Mississippi had the highest

Guiming Wang; Richard B Minnis; Jerrold L Belant; Charles L Wax

2010-01-01

275

Genital ulcers associated with acute Epstein-Barr virus infection  

PubMed Central

To date there have been only five reported cases of females with genital ulceration associated with primary Epstein-Barr virus infection. We describe two further patients and review the clinical features of all seven cases, noting the typical features, particularly purple ulcer margins and systemic symptoms, which should alert the physician to consider this diagnosis. ???

Taylor, S.; Drake, S. M.; Dedicoat, M.; Wood, M. J.

1998-01-01

276

Hepatitis E Virus Infection in Sheltered Homeless Persons, France  

PubMed Central

To determine the prevalence of hepatitis E virus (HEV) infection among sheltered homeless persons in Marseille, France, we retrospectively tested 490 such persons. A total of 11.6% had immunoglobulin (Ig) G and 2.5% had IgM against HEV; 1 person had HEV genotype 3f. Injection drug use was associated with IgG against HEV.

Kaba, Mamadou; Brouqui, Philippe; Richet, Herve; Badiaga, Sekene; Gallian, Pierre; Raoult, Didier

2010-01-01

277

Hepatitis C. Virus Infection: Mechanisms of Disease Progression.  

National Technical Information Service (NTIS)

An estimated 4.1 million individuals in the United States are chronically infected with the hepatitis C virus. Annually 8,000 to 10,000 of these subjects will die of liver-related complications and approximately 1,000 will require liver transplantation. T...

B. Huntley M. H. Sjogren

2006-01-01

278

Sin Nombre Virus Infection in Field Workers, Colorado, USA  

PubMed Central

We report 2 cases of Sin Nombre virus (SNV) infection in field workers, possibly contracted through rodent bites. Screening for antibodies to SNV in rodents trapped in 2 seasons showed that 9.77% were seropositive. Quantitative real-time PCR showed that 2 of 79 deer mice had detectable titers of SNV RNA.

Torres-Perez, Fernando; Wilson, Linda; Collinge, Sharon K.; Harmon, Heath; Ray, Chris; Medina, Rafael A.

2010-01-01

279

Outbreak of West Nile virus infection, Volgograd Region, Russia, 1999.  

PubMed Central

From July 25 to October 1, 1999, 826 patients were admitted to Volgograd Region, Russia, hospitals with acute aseptic meningoencephalitis, meningitis, or fever consistent with arboviral infection. Of 84 cases of meningoencephalitis, 40 were fatal. Fourteen brain specimens were positive in reverse transcriptase-polymerase chain reaction assays, confirming the presence of West Nile/Kunjin virus.

Platonov, A. E.; Shipulin, G. A.; Shipulina, O. Y.; Tyutyunnik, E. N.; Frolochkina, T. I.; Lanciotti, R. S.; Yazyshina, S.; Platonova, O. V.; Obukhov, I. L.; Zhukov, A. N.; Vengerov, Y. Y.; Pokrovskii, V. I.

2001-01-01

280

Chikungunya Virus and Central Nervous System Infections in Children, India  

Microsoft Academic Search

Chikungunya virus (CHIKV) is a mosquito-borne al- phavirus best known for causing fever, rash, arthralgia, and occasional neurologic disease. By using real-time reverse transcription-PCR, we detected CHIKV in plasma samples of 8 (14%) of 58 children with suspected central nervous system infection in Bellary, India. CHIKV was also detected in the cerebrospinal fl uid of 3 children.

Penny Lewthwaite; Ravi Vasanthapuram; Jane C. Osborne; Ashia Begum; Jenna L. M. Plank; M. Veera Shankar; Roger Hewson; Anita Desai; Nick J. Beeching; Ravi Ravikumar; Tom Solomon

2009-01-01

281

Hepatitis E virus infection in pregnant rhesus monkeys.  

PubMed

Ten non-pregnant female monkeys and four pregnant monkeys (all Macaca mulatta) in the last third of their gestation period were infected intravenously with the stool sample of a patient with hepatitis E virus infection (immuno-electronmicroscopy positive for hepatitis E virus). Four more non-pregnant monkeys were inoculated with a lower dose (less number of virus particles by IEM) of a stool sample collected on a different day from the same patient. The average incubation period as evidenced by the rise of serum alanine transferase in the non-pregnant monkeys, was 36.4 +/- 4.9 days. The dose of the virus did not affect the incubation period. Two of the pregnant monkeys had incubation periods of 9 and 13 days respectively. They delivered healthy babies on 40th and 53rd day respectively after inoculation. At the age of 11 months, both babies were negative for anti-HEV antibodies. One monkey which delivered a healthy baby on the 2nd day after inoculation had incubation period of 36 days. The baby of this monkey was anti-HEV positive at the age of 11 months. The incubation period was 41 days in the fourth monkey which delivered a macerated foetus on the 36th day after infection. No fatality was recorded in the infected monkeys. Bile samples collected from all monkeys showed strong signals in nested polymerase chain reaction (PCR). It seems that the incubation period in pregnant monkeys was determined by the state of pregnancy. PMID:8486409

Arankalle, V A; Chadha, M S; Banerjee, K; Srinivasan, M A; Chobe, L P

1993-01-01

282

Hsp70 Protein Positively Regulates Rabies Virus Infection  

PubMed Central

The Hsp70 chaperone plays a central role in multiple processes within cells, including protein translation, folding, intracellular trafficking, and degradation. This protein is implicated in the replication of numerous viruses. We have shown that rabies virus infection induced the cellular expression of Hsp70, which accumulated in Negri body-like structures, where viral transcription and replication take place. In addition, Hsp70 is present in both nucleocapsids purified from infected cells and in purified virions. Hsp70 has been shown to interact with the nucleoprotein N. The downregulation of Hsp70, using specific chaperone inhibitors, such as quercetin or RNA interference, resulted in a significant decrease of the amount of viral mRNAs, viral proteins, and virus particles. These results indicate that Hsp70 has a proviral function during rabies virus infection and suggest that Hsp70 is involved in at least one stage(s) of the viral life cycle, such as viral transcription, translation, and/or production. The mechanism by which Hsp70 controls viral infection will be discussed.

Lahaye, Xavier; Vidy, Aurore; Fouquet, Baptiste

2012-01-01

283

Serodiagnosis of La Crosse virus infections in humans.  

PubMed Central

Serological diagnoses of human infections with California serogroup viruses are usually made by means of complement fixation or hemagglutination inhibition tests or both. An analysis of antibody titers in sera from 128 humans with California (La Crosse) virus infections indicated that exclusive use of the complement fixation tests would have detected only 50% of the actual seroconversions, whereas hemagglutination inhibition and neutralization tests alone would have been sufficient to make the diagnosis in 79.3% and 84.8% of the cases, respectively. These and other results presented demonstrate that the complement fixation test is not sufficiently useful as a primary tool for diagnosis of La Crosse virus infections. We suggest the use of the hemagglutination inhibition test for preliminary screening of sera from individuals with suspect infections caused by California serogroup viruses. The neutralization test should then be used or confirmation and subtype identification. If hemagglutination inhibition and neutralization titers are high and stable, the complement fixation test should then be used as a last, but specific, resort.

Calisher, C H; Bailey, R E

1981-01-01

284

Antiviral therapy and resistance with hepatitis B virus infection  

Microsoft Academic Search

Hepatitis B virus (HBV) infection is still the most com- mon cause of hepatocellular carcinoma and liver cirrho- sis world wide. Recently, however, there has been quite dramatic improvement in the understanding of HBV as- sociated liver disease and its treatment. It has become clear that high viral replication is a major risk factor for the development of both cirrhosis

Hans L Tillmann; Dieter Glebe

2007-01-01

285

The Variegate Neurological Manifestations of Varicella Zoster Virus Infection  

PubMed Central

Varicella zoster virus (VZV) is an exclusively human neurotropic alphaherpesvirus. Primary infection causes varicella (chickenpox), after which the virus becomes latent in ganglionic neurons along the entire neuraxis. With advancing age or immunosuppression, cell-mediated immunity to VZV declines, and the virus reactivates to cause zoster (shingles), dermatomal distribution, pain, and rash. Zoster is often followed by chronic pain (postherpetic neuralgia), cranial nerve palsies, zoster paresis, vasculopathy, meningoencephalitis, and multiple ocular disorders. This review covers clinical, laboratory, and pathological features of neurological complications of VZV reactivation, including diagnostic testing to verify active VZV infection in the nervous system. Additional perspectives are provided by discussions of VZV latency, animal models to study varicella pathogenesis and immunity, and of the value of vaccination of elderly individuals to boost cell-mediated immunity to VZV and prevent VZV reactivation.

Nagel, Maria A.; Cohrs, Randall J.; Mahalingam, Ravi

2014-01-01

286

Studies on Japanese encephalitis virus infection of reptiles. I. Experimental infection of snakes and lizards.  

PubMed

Experimental infection of four species of snakes, Rhabdophis tigrinus tigrinus, Elaphe quadrivirgata, Elaphe climacophora and Agkistrodon halys, and five species of lizards, Takydromus tachydromoides, Eumeces latiscutatus, Eumeces barbouri, Eumeces marginatus oshimensis and Gekko japonicus, with Japanese encephalitis virus (JEV) was carried out. Evidence of JEV multiplication in snakes was not obtained at least under the conditions used in the present study. All lizards except G. japonicus were infected with JEV by ip injection of virus suspension. The minimum infectious dose for a lizard was around 10(3) MLD50/0.05 ml, and this dose was considered to be proportional to the virus dose which is injected into a host by a vector mosquito at a single bite. Temperature dependence of JE virus growth in the lizards was demonstrated. JEV multiplied slower at 20 degrees C than at 26 degrees C, though the peak titers of viremia were equivalent in both groups of lizards kept at 20 degrees C and 26 degrees C. E. latiscutatus developed viremia with ip injection of a partially attenuated strain, Nakayama NIH which could not infect adult mice by peripheral inoculation. T. tachydromoides and E. latiscutatus were also infected by oral feeding of JEV infected mosquitoes. E. latiscutatus was infected by oral feeding of only one infected mosquito. PMID:6141310

Oya, A; Doi, R; Shirasaka, A; Yabe, S; Sasa, M

1983-04-01

287

Differential sensitivity of bat cells to infection by enveloped RNA viruses: coronaviruses, paramyxoviruses, filoviruses, and influenza viruses.  

PubMed

Bats (Chiroptera) host major human pathogenic viruses including corona-, paramyxo, rhabdo- and filoviruses. We analyzed six different cell lines from either Yinpterochiroptera (including African flying foxes and a rhinolophid bat) or Yangochiroptera (genera Carollia and Tadarida) for susceptibility to infection by different enveloped RNA viruses. None of the cells were sensitive to infection by transmissible gastroenteritis virus (TGEV), a porcine coronavirus, or to infection mediated by the Spike (S) protein of SARS-coronavirus (SARS-CoV) incorporated into pseudotypes based on vesicular stomatitis virus (VSV). The resistance to infection was overcome if cells were transfected to express the respective cellular receptor, porcine aminopeptidase N for TGEV or angiotensin-converting enzyme 2 for SARS-CoV. VSV pseudotypes containing the S proteins of two bat SARS-related CoV (Bg08 and Rp3) were unable to infect any of the six tested bat cell lines. By contrast, viral pseudotypes containing the surface protein GP of Marburg virus from the family Filoviridae infected all six cell lines though at different efficiency. Notably, all cells were sensitive to infection by two paramyxoviruses (Sendai virus and bovine respiratory syncytial virus) and three influenza viruses from different subtypes. These results indicate that bat cells are more resistant to infection by coronaviruses than to infection by paramyxoviruses, filoviruses and influenza viruses. Furthermore, these results show a receptor-dependent restriction of the infection of bat cells by CoV. The implications for the isolation of coronaviruses from bats are discussed. PMID:24023659

Hoffmann, Markus; Müller, Marcel Alexander; Drexler, Jan Felix; Glende, Jörg; Erdt, Meike; Gützkow, Tim; Losemann, Christoph; Binger, Tabea; Deng, Hongkui; Schwegmann-Weßels, Christel; Esser, Karl-Heinz; Drosten, Christian; Herrler, Georg

2013-01-01

288

Differential Sensitivity of Bat Cells to Infection by Enveloped RNA Viruses: Coronaviruses, Paramyxoviruses, Filoviruses, and Influenza Viruses  

PubMed Central

Bats (Chiroptera) host major human pathogenic viruses including corona-, paramyxo, rhabdo- and filoviruses. We analyzed six different cell lines from either Yinpterochiroptera (including African flying foxes and a rhinolophid bat) or Yangochiroptera (genera Carollia and Tadarida) for susceptibility to infection by different enveloped RNA viruses. None of the cells were sensitive to infection by transmissible gastroenteritis virus (TGEV), a porcine coronavirus, or to infection mediated by the Spike (S) protein of SARS-coronavirus (SARS-CoV) incorporated into pseudotypes based on vesicular stomatitis virus (VSV). The resistance to infection was overcome if cells were transfected to express the respective cellular receptor, porcine aminopeptidase N for TGEV or angiotensin-converting enzyme 2 for SARS-CoV. VSV pseudotypes containing the S proteins of two bat SARS-related CoV (Bg08 and Rp3) were unable to infect any of the six tested bat cell lines. By contrast, viral pseudotypes containing the surface protein GP of Marburg virus from the family Filoviridae infected all six cell lines though at different efficiency. Notably, all cells were sensitive to infection by two paramyxoviruses (Sendai virus and bovine respiratory syncytial virus) and three influenza viruses from different subtypes. These results indicate that bat cells are more resistant to infection by coronaviruses than to infection by paramyxoviruses, filoviruses and influenza viruses. Furthermore, these results show a receptor-dependent restriction of the infection of bat cells by CoV. The implications for the isolation of coronaviruses from bats are discussed.

Hoffmann, Markus; Muller, Marcel Alexander; Drexler, Jan Felix; Glende, Jorg; Erdt, Meike; Gutzkow, Tim; Losemann, Christoph; Binger, Tabea; Deng, Hongkui; Schwegmann-Wessels, Christel; Esser, Karl-Heinz; Drosten, Christian; Herrler, Georg

2013-01-01

289

Isolation and Serological Comparison of Virus-Coded Proteins of Three Potyviruses Infecting Cucurbitaceous Plants  

Microsoft Academic Search

Summary Cylindrical inclusion proteins (CIPs), amorphous inclusion proteins (AIPs), and virus particles were partially purified from Cucurbita maxima leaves infected with zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus 2 (WMV2), and the watermelon mosaic virus 1 strain of papaya ringspot virus (PRSV-W). Antisera to these individual antigens, except AIPs of ZYMV and WMV2, were prepared and used to determine

Nobuhiro Suzuki; Yukio Shirako; Yoshio Ehara

1990-01-01

290

Vaccination with recombinant modified vaccinia virus Ankara protects against measles virus infection in the mouse and cotton rat model  

Microsoft Academic Search

Modified vaccinia virus Ankara (MVA) has been used as an experimental vaccine vector against respiratory infections. We have tested the safety and immunogenicity of a recombinant virus expressing the hemagglutinin of measles virus (MVA-MV-H) using the mouse model of measles virus induced encephalitis and the cotton rat model for respiratory infection. MVA-MV-H proved to induce a TH1 response, neutralizing antibodies

Gerald Weidinger; Marion Ohlmann; Bernd Schlereth; Gerd Sutter; Stefan Niewiesk

2001-01-01

291

Peripheral NKT cells in simian immunodeficiency virus-infected macaques.  

PubMed

NKT cells are a specialized population of T lymphocytes that have an increasingly recognized role in immunoregulation, including controlling the response to viral infections. The characteristics of NKT cells in the peripheral blood of macaques during simian immunodeficiency virus (SIV) or chimeric simian/human immunodeficiency virus (HIV) (SHIV) infection were assessed. NKT cells comprised a mean of 0.19% of peripheral blood lymphocytes across the 64 uninfected macaques studied. Although the range in the percentages of NKT cells was large (0 to 2.2%), levels were stable over time within individual macaques without SIV/SHIV infection. The majority of NKT cells in macaques were CD4(+) (on average 67%) with smaller populations being CD8(+) (21%) and CD4/CD8 double positive (13%). A precipitous decline in CD4(+) NKT cells occurred in all six macaques infected with CXCR4-tropic SHIV(mn229) early after infection, with a concomitant rise in CD8(+) NKT cells in some animals. The depletion of CD4(+) NKT cells was tightly correlated with the depletion of total CD4(+) T cells. R5-tropic SIV(mac251) infection of macaques resulted in a slower and more variable decline in CD4(+) NKT cells, with animals that were able to control SIV virus levels maintaining higher levels of CD4(+) NKT cells. An inverse correlation between the depletion of total and CD4(+) NKT cells and SIV viral load during chronic infection was observed. Our results demonstrate the infection-driven depletion of peripheral CD4(+) NKT cells during both SHIV and SIV infection of macaques. Further studies of the implications of the loss of NKT cell subsets in the pathogenesis of HIV disease are needed. PMID:19052081

Fernandez, Caroline S; Chan, Angela C; Kyparissoudis, Konstantinos; De Rose, Robert; Godfrey, Dale I; Kent, Stephen J

2009-02-01

292

Association of inconclusive sera for human immunodeficiency virus infection with malaria and Epstein-Barr virus infection in Central Africa.  

PubMed

Among 464 sera from adults in Cameroon, 56 (12.1%) gave inconclusive HIV serology. All were negative for HIV-1 DNA; 44.6% (n = 25) were significantly associated with Plasmodium (42.8%) or Epstein-Barr virus (EBV) (17.8%) infections. In Central Africa, sera giving inconclusive results for HIV are frequently associated with malaria, EBV infection, or both. PMID:24478507

Mbopi-Keou, Francois-Xavier; Ndjoyi-Mbiguino, Angélique; Talla, Frédéric; Péré, Hélène; Kebe, Khady; Matta, Mathieu; Sosso, Maurice Aurelien; Bélec, Laurent

2014-02-01

293

Respiratory Syncytial Virus Infection: From Biology to Therapy A Perspective  

PubMed Central

Respiratory syncytial virus (RSV) is responsible for significant morbidity and mortality, particularly in infants younger than 18 months and in the elderly. To date, there are few effective treatment options available to prevent or treat RSV infections. Attractive therapeutic strategies include targeting host epithelial adhesion molecules required for RSV infection, enhancing localized cell-mediated immunity, interfering with RSV viral gene expression and developing a multigene DNA vaccine. The most recent data supporting the advantages and limitations of each of these approaches are discussed in detail. Several promising strategies offer hope for safe and effective prophylaxis and treatment of RSV infection.

2008-01-01

294

Noninvasive Monitoring of Hepatic Damage from Hepatitis C Virus Infection  

PubMed Central

The mathematical model for the dynamics of the hepatitis C proposed in Avendaño et al. (2002), with four populations (healthy and unhealthy hepatocytes, the viral load of the hepatitis C virus, and T killer cells), is revised. Showing that the reduced model obtained by considering only the first three of these populations, known as basic model, has two possible equilibrium states: the uninfected one where viruses are not present in the individual, and the endemic one where viruses and infected cells are present. A threshold parameter (the basic reproductive virus number) is introduced, and in terms of it, the global stability of both two possible equilibrium states is established. Other central result consists in showing, by model numerical simulations, the feasibility of monitoring liver damage caused by HCV, avoiding unnecessary biopsies and the undesirable related inconveniences/imponderables to the patient; another result gives a mathematical modelling basis to recently developed techniques for the disease assessment based essentially on viral load measurements.

Alavez-Ramirez, J.; Fuentes-Allen, J. L.; Lopez-Estrada, J.

2011-01-01

295

Preservation of RNA and destruction of infectivity in microdissected brain tissues of Lewis rats infected with the Borna disease virus  

Microsoft Academic Search

Laser microdissection combined with real-time RT-PCR presents an advanced tool to quantify particular RNA species in defined tissue areas. Dealing with infectious tissue samples increases the need to overcome the risk of infectivity and contamination during laser microdissection. Here, an useful method to control infectivity of frozen brain sections infected with the Borna disease virus (BDV), an enveloped RNA virus,

Doris Porombka; Sibylle Herzog; Wolfgang Baumgärtner; Christiane Herden

2006-01-01

296

Identification of a Pegivirus (GB Virus-Like Virus) That Infects Horses  

PubMed Central

The recent identification of nonprimate hepaciviruses in dogs and then in horses prompted us to look for pegiviruses (GB virus-like viruses) in these species. Although none were detected in canines, we found widespread natural infection of horses by a novel pegivirus. Unique genomic features and phylogenetic analyses confirmed that the tentatively named equine pegivirus (EPgV) represents a novel species within the Pegivirus genus. We also determined that EPgV causes persistent viremia whereas its clinical significance is undetermined.

Simmonds, Peter; Cullen, John M.; Scheel, Troels K. H.; Medina, Jan L.; Giannitti, Federico; Nishiuchi, Eiko; Brock, Kenny V.; Burbelo, Peter D.; Rice, Charles M.; Lipkin, W. Ian

2013-01-01

297

Role of CD4 endocytosis in human immunodeficiency virus infection.  

PubMed Central

We have analyzed the role of CD4 endocytosis in human immunodeficiency virus (HIV) entry by measuring the infection of HeLa cells expressing various CD4 constructs with endocytosis rates of between 0.2 and 30%/min in a quantitative infectious focus assay. For a number of laboratory-adapted HIV-1 and HIV-2 strains, the highest levels of infection were found on cells with very limited CD4 endocytosis, while cells with efficient CD4 uptake were only poorly infectable, suggesting that CD4 internalization is not required for HIV entry. This was confirmed in a modified assay involving prebinding of HIV-1LAI to HeLa-CD4 cells at 4 degrees C, synchronized virus entry during warming to 37 degrees C, and neutralization of virions remaining at the cell surface with anti-V3 loop antibodies. Warming cells in hypertonic medium inhibited CD4 endocytosis but did not affect the rate or the extent of infection. These studies confirm that HIV infection does not require endocytosis and that laboratory-adapted virus strains can enter HeLa-CD4 cells by fusion at the plasma membrane.

Pelchen-Matthews, A; Clapham, P; Marsh, M

1995-01-01

298

Productive persistent infection of hematopoietic cells by human foamy virus.  

PubMed Central

Human foamy virus can establish persistent infections in human hematopoietic cell lines, such as H92.1.7 (erythroblastoid cells), Jurkat (CD4+ T cells), and U937 (myeloid-monocytic cells). The infection is characterized by constant production of infectious viruses (for > 2 1/2 years) with no cytopathic effects on the host cells. Electron microscopy of the infected cells showed a viral morphology similar to that observed for particles produced after acute infection. We have detected, in addition to the full-length form of bel1, a previously described deletion in the bel1 gene of the proviral DNA in these cells. RNA containing this 301-bp deletion, which mapped to the splice donor and acceptor sites of the intron of the bet gene, was also found in encapsidated virion RNA. However, the presence of this defective provirus harboring the deletion in bel1 does not prevent productive persistence in these chronically infected cells, since the virus titer does not decrease during cultivation.

Yu, S F; Stone, J; Linial, M L

1996-01-01

299

In vivo imaging of cidofovir treatment of cowpox virus infection.  

PubMed

Variola virus and other members of the genus Orthopoxviruses constitute a prominent bioterrorism and public health threat. Treatment with the anti-viral drug cidofovir inhibits replication of orthopoxviruses in vitro and in vivo. In this study, we visualized the effect of cidofovir on viral kinetics in orthopoxvirus infected mice by using whole-body fluorescence imaging (FI). We engineered a cowpox virus (CPV) expressing the enhanced green fluorescent protein (GFP). Single-step growth curves and calculated 50% lethal doses (LD(50)) of wild-type CPX (Wt-CPV) and GFP-expressing CPX (GFP-CPV) were comparable. Whole-body FI first detected GFP fluorescence in the mesenteric tissue of untreated animals on post-infection day (PID) 1. On PID 3 GFP signal was detected throughout the mesentery, in all abdominal organs by PID 5 and in most major organs, except for the heart and brain by PID 6. Infected animals treated with 25mg/kg of cidofovir also began showing signs of viral replication on PID 1, however, the fluorescent signal was limited only to discrete foci throughout the course of the infection. This work describes the first use of an established Orthopox model of infection to evaluate drug efficacy and track virus progression on a macroscopic level. PMID:17524511

Goff, Arthur; Twenhafel, Nancy; Garrison, Aura; Mucker, Eric; Lawler, James; Paragas, Jason

2007-09-01

300

Respiratory Syncytial Virus Infection: Immune Response, Immunopathogenesis, and Treatment  

PubMed Central

Respiratory syncytial virus (RSV) is the single most important cause of lower respiratory tract infection during infancy and early childhood. Once RSV infection is established, the host immune response includes the production of virus-neutralizing antibodies and T-cell-specific immunity. The humoral immune response normally results in the development of anti-RSV neutralizing-antibody titers, but these are often suboptimal during an infant’s initial infection. Even when the production of RSV neutralizing antibody following RSV infection is robust, humoral immunity wanes over time. Reinfection during subsequent seasons is common. The cellular immune response to RSV infection is also important for the clearance of virus. This immune response, vital for host defense against RSV, is also implicated in the immunopathogenesis of severe lower respiratory tract RSV bronchiolitis. Many details of the immunology and immunopathologic mechanisms of RSV disease known at present have been learned from rodent models of RSV disease and are discussed in some detail. In addition, the roles of immunoglobulin E, histamine, and eosinophils in the immunopathogenesis of RSV disease are considered. Although the treatment of RSV bronchiolitis is primarily supportive, the role of ribavirin is briefly discussed. Novel approaches to the development of new antiviral drugs with promising anti-RSV activity in vitro are also described.

Domachowske, Joseph B.; Rosenberg, Helene F.

1999-01-01

301

Molecular and biophysical characterization of TT virus: Evidence for a new virus family infecting humans  

PubMed Central

The recent isolation of a novel DNA virus from the serum of a Japanese patient (T.T.) has provided the latest possible candidate virus associated with cryptogenic hepatitis. In the present study, we report the complete nucleotide sequence of this virus (TTV) isolated from the serum of a West African. Based on PCR studies designed to amplify overlapping regions of the viral genome and sensitivity to digestion with mung bean nuclease, the viral genome is circular and negative stranded, and comprises 3,852 nt, which is 113 nt longer than the prototype isolate from Japan. Cesium chloride density gradient centrifugation demonstrated banding of the virus at 1.31–1.34 g/ml; filtration studies indicated that TTV had a particle size of 30–50 nm. These results suggest that the virus is similar to the Circoviridae, viruses known to infect plants and vertebrates (e.g., birds and swine); however, sequence similarity searches of available databases did not reveal identity between TTV and other viruses. Phylogenetic analyses of a 260-nt region from 151 globally distributed isolates demonstrated the existence of three major TTV genotypes. Several individuals at high risk for infection with parenterally transmitted viruses were infected with more than one genotype. There was no correlation between genotype and geographic origin. Finally, intravenous inoculation of TTV-positive human serum into chimpanzees demonstrated that TTV can be transmitted to primates; no biochemical or histological evidence for hepatitis was obtained. The distinct biophysical and molecular characteristics of TTV suggest that it is a member of a new family of viruses, which we have tentatively named the Circinoviridae.

Mushahwar, Isa K.; Erker, James C.; Muerhoff, A. Scott; Leary, Thomas P.; Simons, John N.; Birkenmeyer, Larry G.; Chalmers, Michelle L.; Pilot-Matias, Tami J.; Dexai, Suresh M.

1999-01-01

302

Dynamics of oliveros virus infection in rodents in central Argentina.  

PubMed

Oliveros virus (OLV) is an arenavirus hosted by the sigmodontine rodent, Necromys benefactus, in central Argentina. We report a 3-year longitudinal field study of the dynamics of OLV infection in host populations from 15 localities in two provinces on the central Argentine pampa. There was an overall 3-year period immunofluorescent antibody prevalence of 25% in the host population, and infected hosts were found throughout the study area. Spill-over infection into common sympatric species was rare. Infection dynamics exhibited many of the patterns seen for other rodent-borne arenaviruses and hantaviruses, but had some unique characteristics. Host population density was highest in autumn and lowest in spring, while antibody prevalence was highest in spring and lowest in autumn. Virus transmission was horizontal: infection was strongly associated with age, reaching 45% prevalence in the oldest individuals, and prevalence of infection was equal among male and female hosts. Infection may have been associated with scars, which were also approximately equally distributed among male and female Necromys. PMID:17760514

Mills, James N; Alva, Herminia; Ellis, Barbara A; Wagoner, Kent D; Childs, James E; Calderón, Gladys; Enría, Delia A; Jahrling, Peter B

2007-01-01

303

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

304

CD81 and Hepatitis C Virus (HCV) Infection  

PubMed Central

Hepatitis C Virus (HCV) infection is a global public health problem affecting over 160 million individuals worldwide. Its symptoms include chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. HCV is an enveloped RNA virus mainly targeting liver cells and for which the initiation of infection occurs through a complex multistep process involving a series of specific cellular entry factors. This process is likely mediated through the formation of a tightly orchestrated complex of HCV entry factors at the plasma membrane. Among HCV entry factors, the tetraspanin CD81 is one of the best characterized and it is undoubtedly a key player in the HCV lifecycle. In this review, we detail the current knowledge on the involvement of CD81 in the HCV lifecycle, as well as in the immune response to HCV infection.

Feneant, Lucie; Levy, Shoshana; Cocquerel, Laurence

2014-01-01

305

The Innate Immune Playbook for Restricting West Nile Virus Infection  

PubMed Central

West Nile virus (WNV) is an emerging mosquito-borne flavivirus that causes annual epidemics of encephalitic disease throughout the world. Despite the ongoing risk to public health, no approved vaccines or therapies exist for use in humans to prevent or combat WNV infection. The innate immune response is critical for controlling WNV replication, limiting virus-induced pathology, and programming protective humoral and cell-mediated immunity to WNV infection. The RIG-I like receptors, Toll-like receptors, and Nod-like receptors detect and respond to WNV by inducing a potent antiviral defense program, characterized by production of type I IFN, IL-1? and expression of antiviral effector genes. Recent research efforts have focused on uncovering the mechanisms of innate immune sensing, antiviral effector genes that inhibit WNV, and countermeasures employed by WNV to antagonize innate immune cellular defenses. In this review, we highlight the major research findings pertaining to innate immune regulation of WNV infection.

Quicke, Kendra M.; Suthar, Mehul S.

2013-01-01

306

Chronic Ulcerative Herpes Simplex Virus Infection of the Vulva  

PubMed Central

Herpes simplex virus infections in HIV-infected individuals can be clinically unusual and difficult to treat due to underlying problems with cell-mediated immunity and the occurrence of antiviral resistance. Additionally, partial or incomplete restoration of immune function may result in chronic ulcerations that require rotational treatments. In this report, we describe the case of a 38-year-old HIV-positive woman who developed the ulcerative form of chronic herpes simplex infection despite highly active antiretroviral therapy and valacyclovir prophylaxis. Repeated intravenous courses of foscarnet and topical cidofovir finally controlled her erosions as her cell-mediated immunity was slowly restored. This case highlights the challenges that still exist in diagnosing and managing this rare presentation of herpes simplex virus

Griffith-Bauer, Kelly; O'Hearn, Mary; Ehst, Benjamin D.

2012-01-01

307

Endemic Lagos bat virus infection in Eidolon helvum.  

PubMed

Phylogenetic analyses suggest lyssaviruses, including Rabies virus, originated from bats. However, the role of bats in the maintenance, transmission and evolution of lyssaviruses is poorly understood. A number of genetically diverse lyssaviruses are present in Africa, including Lagos bat virus (LBV). A high seroprevalence of antibodies against LBV was detected in Eidolon helvum bats. Longitudinal seroprevalence and age-specific seroprevalence data were analysed and capture-mark-recapture (CMR) analysis used to follow 98 bats over 18 months. These data demonstrate endemic infection, with evidence of horizontal transmission, and force of infection was estimated for differing age categories. The CMR analysis found survival probabilities of seronegative and seropositive bats were not significantly different. The lack of increased mortality in seropositive animals suggests infection is not causing disease after extended incubation. These key findings point towards acute transmission of bat lyssaviruses in adapted bat hosts that occurs at a far higher rate than the occurrence of disease. PMID:22370126

Hayman, D T S; Fooks, A R; Rowcliffe, J M; McCrea, R; Restif, O; Baker, K S; Horton, D L; Suu-Ire, R; Cunningham, A A; Wood, J L N

2012-12-01

308

Avian Influenza Virus Infections in Humans  

Microsoft Academic Search

Seroepidemiologic and virologic studies since 1889 suggested that human influenza pandemics were caused by H1, H2, and H3 subtypes of influenza A viruses. If not for the 1997 avian A\\/H5N1 outbreak in Hong Kong of China, subtype H2 is the likely candidate for the next pandemic. However, unlike previous poultry outbreaks of highly pathogenic avian influenza due to H5 that

Samson S. Y. Wong; Kwok-yung Yuen

2006-01-01

309

Human Immunodeficiency Virus Infection and Pregnancy  

PubMed Central

The human immunodeficiency virus (HIV) epidemic is clearly one of the most serious health-care crises in the professional lives of contemporary physicians. It cannot be regarded as a curiosity to be dealt with by inner-city infectious-disease experts, but rather must be considered a problem for all health-care providers and a problem in which the obstetrician-gynecologist has a special role to play.

1994-01-01

310

Encapsulating quantum dots into enveloped virus in living cells for tracking virus infection.  

PubMed

Utilization of quantum dots (QDs) for single virus tracking has attracted growing interest. Through modification of viral surface proteins, viruses can be labeled with various functionalized QDs and used for tracking the routes of viral infections. However, incorporation of QDs on the viral surface may affect the efficiency of viral entry and alter virus-cell interactions. Here, we describe that QDs can be encapsulated into the capsid of vesicular stomatitis virus glycoprotein (VSV-G) pseudotyped lentivirus (PTLV) in living cells without modification of the viral surface. QDs conjugated with modified genomic RNAs (gRNAs), which contain a packaging signal (Psi) sequence for viral genome encapsulation, can be packaged into virions together with the gRNAs. QD-containing PTLV demonstrated similar entry efficiency as the wild-type PTLV. After infection, QD signals entered the Rab5+ endosome and then moved to the microtubule organizing center of the infected cells in a microtubule-dependent manner. Findings in this study are consistent with previously reported infection routes of VSV and VSV-G pseudotyped lentivirus, indicating that our established QD packaging approach can be used for enveloped virus labeling and tracking. PMID:23560365

Zhang, Yuan; Ke, Xianliang; Zheng, Zhenhua; Zhang, Cuiling; Zhang, Zhenfeng; Zhang, Fuxian; Hu, Qinxue; He, Zhike; Wang, Hanzhong

2013-05-28

311

Innate immune responses in hepatitis B virus (HBV) infection  

PubMed Central

Hepatitis B virus (HBV) infection has a low rate of chronicity compared to HCV infection, but chronic liver inflammation can evolve to life threatening complications. Experimental data from HBV infected chimpanzees and HBV transgenic mice have indicated that cytotoxic T cells are the main cell type responsible for inhibition of viral replication, but also for hepatocyte lysis during chronic HBV infection. Their lower activation and impaired function in later stages of infection was suggested as a possible mechanism that allowed for low levels of viral replication. The lack of an interferon response in these models also indicated the importance of adaptive immunity in clearing the infection. Increased knowledge of the signalling pathways and pathogen associated molecular patterns that govern activation of innate immunity in the early stages of viral infections in general has led to a re-evaluation of the innate immune system in HBV infection. Numerous studies have shown that HBV employs active strategies to evade innate immune responses and induce immunosuppression. Some of the immune components targeted by HBV include dendritic cells, natural killer cells, T regulatory cells and signalling pathways of the interferon response. This review will present the current understanding of innate immunity in HBV infection and of the challenges associated with clearing of the HBV infection.

2014-01-01

312

Secondary herpes simplex virus latent infection in transplanted ganglia.  

PubMed Central

Sensory ganglia latently infected with herpes simplex virus (HSV) were transplanted beneath the renal capsule of syngeneic recipients, and the latent infection remaining was investigated. HSV latency-associated transcript (LAT) expression and reactivation of HSV after explant of transplanted dorsal root ganglia were monitored as markers of latency. Two to four weeks after transplantation, both indicated evidence of HSV latency in transplants. At those times, infectious virus was not detected in direct ganglion homogenates. In addition, viral antigen and infected cell polypeptide 4 RNA were not detected. Taken together, the results suggested that HSV latent infection rather than persistent infection was present in transplants. From these results, two explanations seemed possible: latency was maintained in transplanted neurons, or alternatively, latency developed after transplantation, in neurons not previously latently infected. The latter was considered putative secondary latency and was investigated in three ways. First, evidence of reactivation which might serve as a source for secondary latency was evaluated. Reactivation of HSV in transplants was evident from HSV antigen expression (52% of transplants) and the presence of cell-free virus (38% of transplants) 3 to 5 days after transplantation. Second, putative secondary latency was investigated in recipients immunized with HSV prior to receiving latently infected ganglia. Reactivation was not detected 3 to 5 days after transplantation in immunized recipients, and LAT expression was rare in these recipients after 3 to 4 weeks. Lastly, the possibility of secondary latency was investigated by comparing results obtained with standard HSV and with reactivation-defective thymidine kinase-negative (TK-) HSV. Defective reactivation of TK- HSV was demonstrated by immunohistochemistry and by the inability to isolate infectious virus. Donor dorsal root ganglia latently infected with TK+ HSV showed many LAT-positive neurons 2 or more weeks after transplantation (average, 26 per transplant). However, LAT expression was undetectable or minimal > 2 weeks after transplantation in donor ganglia latently infected with TK- HSV (average, 0.2 per transplant). Impaired reactivation of TK- HSV-infected donor ganglia after transplantation, therefore, was correlated with subsequent limited LAT expression. From these results, the occurrence of secondary latency was concluded for ganglia latently infected with TK+ HSV and transplanted beneath the kidney capsule. In vivo reactivation in this transplant model may provide a more useful means to investigate HSV reactivation than in usual in vitro explant models and may complement other in vivo reactivation models. The occurrence of secondary latency was unique. The inhibition of secondary latency by the immune system may provide an avenue to evaluate immunological control of HSV latency. Images

Tenser, R B; Edris, W A; Gaydos, A; Hay, K A

1994-01-01

313

Interleukin-4 causes delayed virus clearance in influenza virus-infected mice.  

PubMed Central

Two different subsets of T cells, Th1 and Th2 cells, have been demonstrated to secrete different profiles of cytokines and to influence various infections in different ways. Whereas cytokines secreted by Th1 cells, particularly gamma interferon, promote the generation of cell-mediated immunity, Th2 cells and their cytokines (interleukin-4 [IL-4], IL-5, IL-10, and IL-13) have been shown to function in recovery from parasitic infections and in antibody responses. In this study, we analyzed the effects of the dominant Th2 cytokine, IL-4, on immunity to virus infection. We assessed the effects of IL-4 on both secondary immune responses by an adoptive transfer assay and primary immune responses by in vivo treatment of influenza virus-infected mice with IL-4. The results demonstrated that IL-4 can function to inhibit antiviral immunity at both stages. We found that IL-4 treatment of sensitized cells during secondary stimulation in vitro had little effect on their ability to lyse virus-infected target cells in a 51Cr release assay. Nevertheless, the clearance of influenza A/PR/8/34 (H1N1) virus from the lungs of infected BALB/c mice was significantly delayed after the transfer of virus-specific T cells secondarily stimulated in the presence of IL-4 in comparison to virus clearance in recipients of cells stimulated in the absence of IL-4. In contrast to the adoptive transfer results, the treatment of PR8 virus-infected mice with IL-4 during primary infection greatly suppressed the generation of cytotoxic T-cell precursors, as assessed by secondary stimulation in vitro. In addition, culture supernatants of secondarily stimulated spleen cells from IL-4-treated mice contained significantly less gamma interferon and more IL-4 than did spleen cells from controls. More importantly, the treatment of mice with IL-4 resulted in an extremely significant delay in virus clearance. Thus, IL-4 can inhibit both primary and secondary antiviral immune responses.

Moran, T M; Isobe, H; Fernandez-Sesma, A; Schulman, J L

1996-01-01

314

Cutaneous manifestations of opportunistic infections in patients infected with human immunodeficiency virus.  

PubMed Central

Bacillary angiomatosis (BA) presents most commonly as a cutaneous disease and is caused by two organisms. Bartonella (Rochalimaea) henselae and Bartonella (Rochalimaea) quintana. Biopsy confirmation of cutaneous BA is essential because lesions can mimic nodular Kaposi's sarcoma in appearance. Although the vast majority of human immunodeficiency virus (HIV)-infected patients with BA have CD4 lymphocyte counts of less than 100 cells per mm3, the disease responds well to antimicrobial therapy. Staphylococcus aureus is the most common bacterial skin pathogen affecting HIV-infected patients. The prevalence of skin disease due to S. aureus may be explained by high nasal carriage rates for the organism ( > or = 50%) and altered immune function in conjunction with an impaired cutaneous barrier. Herpes simplex virus causes mucocutaneous disease early in the course HIV infection and ulcerative lesions at any site in advanced HIV infection. Herpes zoster is common early in the course of HIV infection; recurrent and disseminated herpes zoster infections are characteristic of patients with advanced HIV disease. Acyclovir resistance is usually seen in patients with large, untreated, ulcerative lesions of herpes simplex virus and in patients with chronic, verrucous lesions of varicella-zoster virus. Cutaneous cryptococcosis, histoplasmosis, and coccidiomycosis are markers of disseminated disease and require biopsy confirmation. Scabies is easily diagnosed but may be atypical in presentation and difficult to eradicate in advanced HIV disease.

Tappero, J W; Perkins, B A; Wenger, J D; Berger, T G

1995-01-01

315

Embryonic infection with the endogenous avian leukosis virus Rous-associated virus-0 alters responses to exogenous avian leukosis virus infection.  

PubMed Central

We inoculated susceptible chicken embryos with the endogenous avian leukosis virus Rous-associated virus-0 (RAV-0) on day 6 of incubation. At 1 week after hatching, RAV-0-infected and control chickens were inoculated with either RAV-1 or RAV-2, exogenous viruses belonging to subgroups A and B, respectively. The chickens injected with RAV-0 as embryos remained viremic with exogenous virus longer and either failed to develop type-specific humoral immunity to exogenous virus or developed it later than the control chickens not inoculated with RAV-0. The RAV-0-injected chickens also developed neoplasms at a much higher frequency than did the control chickens. We suggest that the lower immune responses of the RAV-0-injected chickens were due to an immunological tolerance to envelope group-specific glycoproteins shared among endogenous and exogenous viruses.

Crittenden, L B; McMahon, S; Halpern, M S; Fadly, A M

1987-01-01

316

Antiviral activity of ginseng extract against respiratory syncytial virus infection  

PubMed Central

Panax ginseng has been known to have a number of immuno-modulatory effects. In this study, we investigated whether Panax Korean red ginseng extract (KRGE) has in vitro and in vivo antiviral effects on respiratory syncytial virus (RSV) infection. KRGE improved the survival of human lung epithelial cells against RSV infection and inhibited RSV replication. In addition, KRGE treatment suppressed the expression of RSV-induced inflammatory cytokine genes (IL-6 and IL-8) and the formation of reactive oxygen species in epithelial cell cultures. Oral administration of mice with KRGE resulted in lowering lung viral loads after RSV infection. Additionally, the in vivo effects of KRGE showed an enhanced level of interferon-? (IFN-?) producing dendritic cells subsequent to RSV infection. Taken together, these results suggested that KRGE has antiviral activity against RSV infection.

LEE, JONG SEOK; KO, EUN-JU; HWANG, HYE SUK; LEE, YU-NA; KWON, YOUNG-MAN; KIM, MIN-CHUL; KANG, SANG-MOO

2014-01-01

317

Antiviral activity of ginseng extract against respiratory syncytial virus infection.  

PubMed

Panax ginseng has been known to have a number of immuno-modulatory effects. In this study, we investigated whether Panax Korean red ginseng extract (KRGE) has in vitro and in vivo antiviral effects on respiratory syncytial virus (RSV) infection. KRGE improved the survival of human lung epithelial cells against RSV infection and inhibited RSV replication. In addition, KRGE treatment suppressed the expression of RSV-induced inflammatory cytokine genes (IL-6 and IL-8) and the formation of reactive oxygen species in epithelial cell cultures. Oral administration of mice with KRGE resulted in lowering lung viral loads after RSV infection. Additionally, the in vivo effects of KRGE showed an enhanced level of interferon-? (IFN-?) producing dendritic cells subsequent to RSV infection. Taken together, these results suggested that KRGE has antiviral activity against RSV infection. PMID:24756136

Lee, Jong Seok; Ko, Eun-Ju; Hwang, Hye Suk; Lee, Yu-Na; Kwon, Young-Man; Kim, Min-Chul; Kang, Sang-Moo

2014-07-01

318

Dermatological manifestations of hepatitis C virus infection in Saudi Arabia.  

PubMed

The Saudi Ministry of Health data indicates that almost 32% of viral hepatitis cases were caused by hepatitis C virus (HCV). It has been widely reported that chronic HCV infection is associated with and may trigger or exacerbate many skin manifestations in 20-40% of patients visiting dermatologists. The most commonly encountered dermatological manifestations of HCV infection globally include mixed cryoglobulinemia, porphyria cutanea tarda, cutaneous and/or oral lichen planus, urticaria, pruritus, thrombocytopenic purpura, and psoriasis. The current article indicates that HCV infection is increasing in Saudi Arabia and approximately 12% of the reported dermatological manifestations are caused by HCV infection. We recommend the urgent need for large-scale, case-control studies to understand the impact of HCV infection in patients with skin disease. PMID:24888650

Halawani, Mona R

2014-06-01

319

Methadone Enhances Human Immunodeficiency Virus Infection of Human Immune Cells  

PubMed Central

Opiate abuse has been postulated to be a cofactor in the immunopathogenesis of acquired immunodeficiency syndrome (AIDS). This study evaluated whether methadone, a drug widely prescribed for the treatment of drug abusers with opioid dependence, affects human immunodeficiency virus (HIV) infection of human immune cells. When added to human fetal microglia and blood monocyte–derived macrophage cultures, methadone significantly enhanced HIV infection of these cells. This enhancement was associated with the up-regulation of expression of CCR5, a primary coreceptor for macrophage-tropic HIV entry into macrophages. Most importantly, the addition of methadone to the cultures of latently infected peripheral blood mononuclear cells from HIV-infected patients enhanced viral activation and replication. Although the in vivo relevance of these findings remains to be determined, the data underscore the necessity of further studies to define the role of opioids, including methadone, in the immunopathogenesis of HIV infection and AIDS.

Li, Yuan; Wang, Xu; Tian, Sha; Guo, Chang-Jiang; Douglas, Steven D.; Ho, Wen-Zhe

2014-01-01

320

Proteomic analysis of primary duck hepatocytes infected with duck hepatitis B virus  

Microsoft Academic Search

BACKGROUND: Hepatitis B virus (HBV) is a major cause of liver infection in human. Because of the lack of an appropriate cell culture system for supporting HBV infection efficiently, the cellular and molecular mechanisms of hepadnavirus infection remain incompletely understood. Duck heptatitis B virus (DHBV) can naturally infect primary duck hepatocytes (PDHs) that provide valuable model systems for studying hepadnavirus

Yanfeng Zhao; Haijing Ben; Su Qu; Xinwen Zhou; Liang Yan; Bin Xu; Shuangcheng Zhou; Qiang Lou; Rong Ye; Tianlun Zhou; Pengyuan Yang; Di Qu

2010-01-01

321

Control of mucosal virus infection by influenza nucleoprotein-specific CD8+ cytotoxic T lymphocytes  

Microsoft Academic Search

BACKGROUND: MHC class I-restricted CD8+ cytotoxic T lymphocytes (CTL) are thought to play a major role in clearing virus and promoting recovery from influenza infection and disease. This has been demonstrated for clearance of influenza virus from the lungs of infected mice. However, human influenza infection is primarily a respiratory mucosal infection involving the nasopharynx and tracheobronchial tree. The role

Innocent N Mbawuike; Yongxin Zhang; Robert B Couch

2007-01-01

322

Dynamics of influenza A virus infections in permanently infected pig farms: evidence of recurrent infections, circulation of several swine influenza viruses and reassortment events.  

PubMed

Concomitant infections by different influenza A virus subtypes within pig farms increase the risk of new reassortant virus emergence. The aims of this study were to characterize the epidemiology of recurrent swine influenza virus infections and identify their main determinants. A follow-up study was carried out in 3 selected farms known to be affected by repeated influenza infections. Three batches of pigs were followed within each farm from birth to slaughter through a representative sample of 40 piglets per batch. Piglets were monitored individually on a monthly basis for serology and clinical parameters. When a flu outbreak occurred, daily virological and clinical investigations were carried out for two weeks. Influenza outbreaks, confirmed by influenza A virus detection, were reported at least once in each batch. These outbreaks occurred at a constant age within farms and were correlated with an increased frequency of sneezing and coughing fits. H1N1 and H1N2 viruses from European enzootic subtypes and reassortants between viruses from these lineages were consecutively and sometimes simultaneously identified depending on the batch, suggesting virus co-circulations at the farm, batch and sometimes individual levels. The estimated reproduction ratio R of influenza outbreaks ranged between 2.5 [1.9-2.9] and 6.9 [4.1-10.5] according to the age at infection-time and serological status of infected piglets. Duration of shedding was influenced by the age at infection time, the serological status of the dam and mingling practices. An impaired humoral response was identified in piglets infected at a time when they still presented maternally-derived antibodies. PMID:24007505

Rose, Nicolas; Hervé, Séverine; Eveno, Eric; Barbier, Nicolas; Eono, Florent; Dorenlor, Virginie; Andraud, Mathieu; Camsusou, Claire; Madec, François; Simon, Gaëlle

2013-01-01

323

Herpes Virus Infection of RPE and MDCK Cells: Polarity of Infection  

Microsoft Academic Search

Our objective was to determine quantitatively whether herpes simplex virus infects preferentially the apical or basolateral surfaces of two well-differentiated cell types, human retinal pigment epithelial cells and Madin-Darby canine kidney epithelial cells. Secondarily, we sought to localize the mannose 6-phosphate\\/insulin-like growth factor II receptor, a putative receptor for herpes simplex virus, in the membrane domains of the retinal pigment

KIMBERLY S. TOPP; ALANA L. ROTHMAN; JENNIFER H. LAVAIL

1997-01-01

324

A Case of Giant Hepatic Hydatid Cyst Infected with Morganella morganii and the Literature Review  

PubMed Central

Hydatid cyst disease is a common worldwide zoonosis. Most of the cysts are located in the liver. Abscess formation due to infection of the cyst is an important complication. M. morganii, a Gram-negative Bacillus, is a quite rare cause of liver abscess. A 77-year-old woman was admitted to hospital with complaints of fever, chills, nausea, vomiting, loss of appetite, and abdominal pain located in the right-upper quadrant. Her history was positive for hepatic hydatid cyst disease ten years ago. Physical examination revealed a painful mass filling the right-upper quadrant and extending down to umbilicus. Indirect hemagglutinin test for hydatid cyst was positive at a titer of 1/320. Giant liver abscess due to infected hydatid cyst was found in computed tomography scan. Surgeons performed cystectomy and cholecystectomy. Cefazoline, cefuroxime, and metronidazole were administered empirically, but all the three agents were replaced with intravenous ceftriaxone after M. morganii was isolated from the cultures of the abscess material. Clinical signs of the patient resolved at the second week of treatment, and she was discharged.

Hakyemez, Ismail Necati; Sit, Mustafa; Aktas, Gulali; Tas, Tekin; Mengeloglu, F?rat Zafer; Kucukbayrak, Abdulkadir

2012-01-01

325

Clinical presentation of GB-C virus infection in drug abusers with chronic hepatitis C  

Microsoft Academic Search

Background\\/Aims: Recently, the hepatitis GB-C virus (GBV-C) has been identified as another virus potentially causing chronic hepatitis. Although high rates of coinfection are emerging in drug addicts with chronic hepatitis C virus infection, no detailed data on clinical presentation are available. Therefore, co-infection was sought in hepatitis C virus patients to determine the impact of GB-C virus on clinical presentation.Methods:

Tobias Goeser; Stefanie Seipp; Rafael Wahl; Hubert M. Müller; Wolfgang Stremmel; Lorenz Theilmann

1997-01-01

326

Current therapy for hepatitis C or D or immunodeficiency virus concurrent infection with chronic hepatitis B  

Microsoft Academic Search

Concurrent hepatitis C virus (HCV), hepatitis delta virus (HDV), or human immunodeficiency virus (HIV) infection with chronic\\u000a hepatitis B virus (HBV) appears to increase the risk of progressive liver disease including liver cirrhosis and hepatocellular\\u000a carcinoma. There is a 10% prevalence of HCV infection in chronic HBV or HDV infection. Serological evidence of previous exposure\\u000a to HBV is found in

Rong-Nan Chien

2008-01-01

327

High doses of highly pathogenic avian influenza virus in chicken meat are required to infect ferrets  

PubMed Central

High pathogenicity avian influenza viruses (HPAIV) have caused fatal infections in mammals through consumption of infected bird carcasses or meat, but scarce information exists on the dose of virus required and the diversity of HPAIV subtypes involved. Ferrets were exposed to different HPAIV (H5 and H7 subtypes) through consumption of infected chicken meat. The dose of virus needed to infect ferrets through consumption was much higher than via respiratory exposure and varied with the virus strain. In addition, H5N1 HPAIV produced higher titers in the meat of infected chickens and more easily infected ferrets than the H7N3 or H7N7 HPAIV.

2014-01-01

328

STAT2 signaling and dengue virus infection  

PubMed Central

Dengue virus (DENV) is an important human pathogen whose byzantine relationship with the immune response is poorly understood. DENV causes dengue fever and dengue hemorrhagic fever/dengue shock syndrome, diseases for which palliative care is the only treatment. DENV immunopathogenesis studies are complicated by the lack of an immunocompetent small-animal model, and this has hindered anti-DENV drug and vaccine development. This review describes strategies that DENV uses to evade the type I interferon response and focuses on how data gained from the study of DENV NS5-mediated STAT2 degradation may be used to create immunocompetent DENV mouse models and design anti-DENV therapeutics.

Morrison, Juliet; Garcia-Sastre, Adolfo

2014-01-01

329

The ABC of Epstein-Barr virus infections.  

PubMed

The EBV has evolved mechanisms that allow it to take advantages of different aspects of the human immune system, resulting in evasion of the defense mechanisms of the host. The virus is capable of resting calmly in a "sea of tranquility". The virus has the unique ability among herpesviruses to transform infected B lymphocytes, thereby creating the potential for uncontrolled lymphoproliferation. Such lymphoproliferation occurs when the immune system is deregulated as a result of inborn defects or acquired defects (e.g., XLP syndrome and organ transplantation, respectively). Otherwise, EBV is kept in check by the surveillance activity of cytotoxic T lymphocytes and NK cells. PMID:16107064

Allen, Upton D

2005-01-01

330

Inhibition of a plant virus infection by analogs of melittin.  

PubMed Central

An approach that enables identification of specific synthetic peptide inhibitors of plant viral infection is reported. Synthetic analogs of melittin that have sequence and structural similarities to an essential domain of tobacco mosaic virus coat protein were found to possess highly specific antiviral activity. This approach involves modification of residues located at positions analogous to those that are critical for virus assembly. The degree of inhibition found correlates well with sequence similarities between the viral capsid protein and the melittin analogs studied as well as with the induced conformational changes that result upon interaction of the peptides and ribonucleic acid. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

Marcos, J F; Beachy, R N; Houghten, R A; Blondelle, S E; Perez-Paya, E

1995-01-01

331

Multiple roles of the coagulation protease cascade during virus infection.  

PubMed

The coagulation cascade is activated during viral infections. This response may be part of the host defense system to limit spread of the pathogen. However, excessive activation of the coagulation cascade can be deleterious. In fact, inhibition of the tissue factor/factor VIIa complex reduced mortality in a monkey model of Ebola hemorrhagic fever. Other studies showed that incorporation of tissue factor into the envelope of herpes simplex virus increases infection of endothelial cells and mice. Furthermore, binding of factor X to adenovirus serotype 5 enhances infection of hepatocytes but also increases the activation of the innate immune response to the virus. Coagulation proteases activate protease-activated receptors (PARs). Interestingly, we and others found that PAR1 and PAR2 modulate the immune response to viral infection. For instance, PAR1 positively regulates TLR3-dependent expression of the antiviral protein interferon ?, whereas PAR2 negatively regulates expression during coxsackievirus group B infection. These studies indicate that the coagulation cascade plays multiple roles during viral infections. PMID:24632711

Antoniak, Silvio; Mackman, Nigel

2014-04-24

332

Frontiers in the Treatment of Hepatitis C Virus Infection  

PubMed Central

In the United States, chronic hepatitis C virus (HCV) infection is the leading cause of blood-borne, virus-associated death related to advanced liver disease and the leading indication for liver transplantation. Although the diagnostic test for HCV has been available for more than 20 years, the majority of persons with HCV infection still have not received a diagnosis. This has led to a recent change in screening recommendations by the Centers for Disease Control and Prevention. Moreover, new medications were approved in 2011 after nearly a decade of minimal progress in the development of treatments for HCV infection. This was followed by the highly anticipated approval of sofosbuvir and simeprevir in 201 3. In the past 3 years, there has been an explosion of reports on medications from different classes, promising a dramatic expansion to an all-oral regimen for the treatment of HCV genotype 1 infection within the next few years. This article reviews the current screening recommendations and standard of care for treatment of HCV infection and highlights specific agents in the pipeline that should change the landscape of how HCV infection is treated in the near future.

Ahn, Joseph

2014-01-01

333

Frontiers in the treatment of hepatitis C virus infection.  

PubMed

In the United States, chronic hepatitis C virus (HCV) infection is the leading cause of blood-borne, virus-associated death related to advanced liver disease and the leading indication for liver transplantation. Although the diagnostic test for HCV has been available for more than 20 years, the majority of persons with HCV infection still have not received a diagnosis. This has led to a recent change in screening recommendations by the Centers for Disease Control and Prevention. Moreover, new medications were approved in 2011 after nearly a decade of minimal progress in the development of treatments for HCV infection. This was followed by the highly anticipated approval of sofosbuvir and simeprevir in 201 3. In the past 3 years, there has been an explosion of reports on medications from different classes, promising a dramatic expansion to an all-oral regimen for the treatment of HCV genotype 1 infection within the next few years. This article reviews the current screening recommendations and standard of care for treatment of HCV infection and highlights specific agents in the pipeline that should change the landscape of how HCV infection is treated in the near future. PMID:24803873

Ahn, Joseph; Flamm, Steven L

2014-02-01

334

Begomoviruses infecting weeds in Cuba: increased host range and a novel virus infecting Sida rhombifolia.  

PubMed

As a result of surveys conducted during the last few years to search for wild reservoirs of begomoviruses in Cuba, we detected a novel bipartite begomovirus, sida yellow mottle virus (SiYMoV), infecting Sida rhombifolia plants. The complete genome sequence was obtained, showing that DNA-A was 2622 nucleotides (nt) in length and that it was most closely related (87.6% nucleotide identity) to DNA-A of an isolate of sida golden mosaic virus (SiGMV) that infects snap beans (Phaseolus vulgaris) in Florida. The DNA-B sequence was 2600 nt in length and shared the highest nucleotide identity (75.1%) with corchorus yellow spot virus (CoYSV). Phylogenetic relationship analysis showed that both DNA components of SiYMoV were grouped in the Abutilon clade, along with begomoviruses from Florida and the Caribbean islands. We also present here the complete nucleotide sequence of a novel strain of sida yellow vein virus found infecting Malvastrum coromandelianum and an isolate of euphorbia mosaic virus that was found for the first time infecting Euphorbia heterophylla in Cuba. PMID:21964921

Fiallo-Olivé, Elvira; Navas-Castillo, Jesús; Moriones, Enrique; Martínez-Zubiaur, Yamila

2012-01-01

335

Challenges in managing hepatitis C virus infection in cancer patients.  

PubMed

Cancer patients have unique problems associated with hepatitis C virus (HCV) infection and treatment not seen in the general population. HCV infection poses additional challenges and considerations for the management of cancer, and vice versa. HCV infection also can lead to the development of cancer, particularly hepatocellular carcinoma and non-Hodgkin lymphoma. In severely immunocompromised cancer patients, diagnosis of HCV infection requires increased reliance on RNA detection techniques. HCV infection can affect chemotherapy, and delay of HCV infection treatment until completion of chemotherapy and achievement of cancer remission may be required to decrease the potential for drug-drug interactions between antineoplastic agents and HCV therapeutics and potentiation of side effects of these agents. In addition, hematopoietic stem cell transplant (HSCT) recipients have an increased risk of early development of cirrhosis and fibrosis. Whether this increased risk applies to all patients regardless of cancer treatment is unknown. Furthermore, patients with cancer may have poorer sustained virological responses to HCV infection treatment than do those without cancer. Unfortunately, not all cancer patients are candidates for HCV infection therapy. In this article, we review the challenges in managing HCV infection in cancer patients and HSCT recipients. PMID:24659870

Borchardt, Roy A; Torres, Harrys A

2014-03-21

336

Juvenile rheumatoid arthritis in children with Ebstein Barr virus infection.  

PubMed

Juvenile Rheumatoid Arthritis (JRA) is a disease of unknown etiology. A total of 50 patients with JRA who were hospitalized in the Pediatrics Rheumatology Ward of Imam Khomeini Hospital in Tehran during the years 2001-2002, were assessed serologically (IgM and IgG specific viral capsid antigens) for EBV infection and their response to therapy was studied. Minimum age of the patients was at least 6 months and mean age was 60.96 plus/minus 43.46 months. EBV infection was seen in 44 (88%) patients 24 of whom were girls and 20 boys. Ninety two percent of girls and 83% boys were infected with the virus. Ebstein barr virus (EBV) infection was seen in 33 cases, 6 cases, 4 cases and 1 case in the polyarticular, pauciarticular, systemic and spondylitis group, respectively. Fifty four percent of EBV-positive patients with JRA did not respond to the classic therapy. EBV virus is involved in the pathogenesis of JRA and patients with EBV are in greater risk of developing JRA. PMID:19093474

Aghighi, Y; Gilani Sh, Modarres; Razavi, M; Zamani, A; Daneshjoo, K

2007-10-15

337

Review: Occult hepatitis C virus infection: Still remains a controversy.  

PubMed

Occult hepatitis C virus (HCV) infection is characterized by the presence of HCV RNA in the liver cells or peripheral blood mononuclear cells of the patients whose serum samples test negative for HCV RNA, with or without presence of HCV antibodies. The present study reviews the existing literature on the persistence of occult hepatitis C virus infection, with description of the clinical characteristics and methods for identification of occult hepatitis C. Occult hepatitis C virus infection was detected in patients with abnormal results of liver function tests of unknown origin, with HCV antibodies and HCV RNA negativity in serum, and also in patients with spontaneous or treatment-induced recovery from hepatitis C. The viral replication in the liver cells and/or peripheral blood mononuclear cells was present in all clinical presentations of occult hepatitis C. The peripheral blood mononuclear cells represent an extra-hepatic site of HCV replication. The reason why HCV RNA was not detectable in the serum of patients with occult hepatitis C, could be the low number of circulating viral particles not detectable by the diagnostic tests with low sensitivity. It is uncertain whether occult hepatitis C is a different clinical entity or just a form of chronic hepatitis C virus infection. Data accumulated over the last decade demonstrated that an effective approach to the diagnosis of HCV infection would be the implementation of more sensitive HCV RNA diagnostic assays, and also, examination of the presence of viral particles in the cells of the immune system. J. Med. Virol. 86:1491-1498, 2014. © 2014 Wiley Periodicals, Inc. PMID:24895180

Dzekova Vidimliski, Pavlina; Nikolov, Igor; Matevska Geshkovska, Nadica; Dimovski, Aleksandar; Rostaing, Lionel; Sikole, Aleksandar

2014-09-01

338

Clinical Evaluation of a Rapid Immunochromatographic Test for the Diagnosis of Dengue Virus Infection  

PubMed Central

A rapid immunochromatographic test was compared to the hemagglutination inhibition assay for separate determinations of dengue virus-specific immunoglobulin M (IgM) and IgG levels in paired serum specimens from 92 patients (34 with primary dengue virus infection, 35 with secondary dengue virus infection, and 23 without dengue virus infection). The rapid test showed 99% sensitivity in the diagnosis of dengue virus infection. The majority (30 of 34 [88%]) of patients with primary infection showed positive IgM but negative IgG, while 34 of 35 (97%) patients with secondary infection showed positive IgG with or without IgM. Specificity in nonflavivirus infections was 96% (1 of 23 positive). The rapid test should be a useful aid in rapid diagnosis of dengue virus infection.

Sang, Chew Theng; Hoon, Lim Siew; Cuzzubbo, Andrea; Devine, Peter

1998-01-01

339

Clinical evaluation of a rapid immunochromatographic test for the diagnosis of dengue virus infection.  

PubMed

A rapid immunochromatographic test was compared to the hemagglutination inhibition assay for separate determinations of dengue virus-specific immunoglobulin M (IgM) and IgG levels in paired serum specimens from 92 patients (34 with primary dengue virus infection, 35 with secondary dengue virus infection, and 23 without dengue virus infection). The rapid test showed 99% sensitivity in the diagnosis of dengue virus infection. The majority (30 of 34 [88%]) of patients with primary infection showed positive IgM but negative IgG, while 34 of 35 (97%) patients with secondary infection showed positive IgG with or without IgM. Specificity in nonflavivirus infections was 96% (1 of 23 positive). The rapid test should be a useful aid in rapid diagnosis of dengue virus infection. PMID:9606000

Sang, C T; Hoon, L S; Cuzzubbo, A; Devine, P

1998-05-01

340

Experimental "Runde" virus infections in embryonated eggs and chickens.  

PubMed

Three-day-old chicks and 11-12 day embryonated eggs were inoculated with 100 BMLD50 (baby mouse lethal doses) of Runde virus. Chicks were infected subcutaneously and eggs in the allantoic or amniotic cavities, in the yolk sac, or on the chorioallantoic membrane. "Runde" virus produced viraemia and antibody responses in 3-day-old chicks. The virus multiplied only in the amniotic cavity of the embryonated eggs and was detected in the brains of the embryos from day 5-9 p.i. Out of five eggs left to hatch, two hatched on time, while in three unhatched eggs the chicks were alive but extremely weak. Virus was detected in the brains of all five chicks, and high antibody titres were found in the two which hatched. These two chicks had "epilepsy-like" attacks. The results suggested that one passage in chicks or eggs reduced the mouse pathogenicity of "Runde" virus. No antigenic difference between chick- and mouse-passaged virus could be demonstrated by gel precipitation. PMID:716921

Traavik, T

1978-10-01

341

Ebola virus-like particles protect from lethal Ebola virus infection  

Microsoft Academic Search

The filovirus Ebola causes hemorrhagic fever with 70-80% human mortality. High case-fatality rates, as well as known aerosol infectivity, make Ebola virus a potential global health threat and possible biological warfare agent. Development of an effective vaccine for use in natural outbreaks, response to biological attack, and protection of laboratory workers is a higher national priority than ever before. Coexpression

Kelly L. Warfield; Catharine M. Bosio; Brent C. Welcher; Emily M. Deal; Mansour Mohamadzadeh; Alan Schmaljohn; M. Javad Aman; Sina Bavari

2003-01-01

342

Reappearance of Founder Virus Sequence in Human Immunodeficiency Virus Type 1Infected Patients  

Microsoft Academic Search

Different patterns of temporal evolution in human immunodeficiency virus type 1 V3 and p17 regions are described for eight patients studied during the first years following primary infection. In samples from three patients, a rapid replacement of the major sequence occurred but the original sequence reappeared later simultaneously with clinical deterioration and increased plasma viral load. A restricted sequence heterogeneity

ANNIKA C. KARLSSON; HANS GAINES; MATTI SALLBERG; STEFAN LINDBACK; ANDERS SONNERBORG

1999-01-01

343

Hepatitis A virus infections in Voyvodina.  

PubMed Central

Sera of 1000 persons in Voyvodina were tested with radioimmunoassay for antibodies against hepatitis A virus (HAV). The morbidity and age incidence of positive findings have been analysed and compared with relevant findings in other countries. Below the age of 19 years the morbidity rates are higher (0.138 to 0.595 per mill) and the prevalences of seropositives are lower (17.1-64.0%) than the respective frequencies above that age (0.011 to 0.052 per mill and 85.7-98.7% respectively). Below the first year of life seropositivity is more frequent than in 1- to 14-year old children. After the first year until the age of 30-39 years the frequency of seropositives increases with increasing age up to a maximum of about 90%.

Vukovic, B. S.; Roncevic, N.; Borota, R.; Terzin, A. L.

1981-01-01

344

Inhibition of African swine fever virus binding and infectivity by purified recombinant virus attachment protein p12.  

PubMed Central

The African swine fever virus protein p12, involved in virus attachment to the host cell, has an apparent molecular mass of 17 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions. We have also identified 12- and 10-kDa forms of the p12 protein in infected Vero cells and found that the mature 17-kDa protein is the only form present in virus particles. The p12 protein has been produced in large amounts in Spodoptera frugiperda insect cells infected with a recombinant baculovirus. A 17-kDa protein that possessed the biological properties of the viral protein was produced, since it bound to susceptible Vero cells and not to receptor-negative L cells, which do not support virus replication. The binding of the baculovirus-expressed protein p12 to Vero cells was specifically blocked by virus particles. In addition, the recombinant protein purified by immunoaffinity chromatography blocked the specific binding of virus particles to susceptible cells and prevented infection, demonstrating that the p12 protein mediates the attachment of virions to specific receptors and indicating that blocking the p12-mediated interaction between African swine fever virus and receptors in Vero cells can inhibit infection. However, although antibodies specific for protein p12 are induced in natural infections and in animals inoculated with inactivated virus or recombinant protein p12, these antisera did not inhibit virus binding to the host cell or neutralize virus infectivity. Images

Angulo, A; Vinuela, E; Alcami, A

1993-01-01

345

Host and viral translational mechanisms during cricket paralysis virus infection.  

PubMed

The dicistrovirus is a positive-strand single-stranded RNA virus that possesses two internal ribosome entry sites (IRES) that direct translation of distinct open reading frames encoding the viral structural and nonstructural proteins. Through an unusual mechanism, the intergenic region (IGR) IRES responsible for viral structural protein expression mimics a tRNA to directly recruit the ribosome and set the ribosome into translational elongation. In this study, we explored the mechanism of host translational shutoff in Drosophila S2 cells infected by the dicistrovirus, cricket paralysis virus (CrPV). CrPV infection of S2 cells results in host translational shutoff concomitant with an increase in viral protein synthesis. CrPV infection resulted in the dissociation of eukaryotic translation initiation factor 4G (eIF4G) and eIF4E early in infection and the induction of deIF2alpha phosphorylation at 3 h postinfection, which lags after the initial inhibition of host translation. Forced dephosphorylation of deIF2alpha by overexpression of dGADD34, which activates protein phosphatase I, did not prevent translational shutoff nor alter virus production, demonstrating that deIF2alpha phosphorylation is dispensable for host translational shutoff. However, premature induction of deIF2alpha phosphorylation by thapsigargin treatment early in infection reduced viral protein synthesis and replication. Finally, translation mediated by the 5' untranslated region (5'UTR) and the IGR IRES were resistant to impairment of eIF4F or eIF2 in translation extracts. These results support a model by which the alteration of the deIF4F complex contribute to the shutoff of host translation during CrPV infection, thereby promoting viral protein synthesis via the CrPV 5'UTR and IGR IRES. PMID:19889774

Garrey, Julianne L; Lee, Yun-Young; Au, Hilda H T; Bushell, Martin; Jan, Eric

2010-01-01

346

Host and Viral Translational Mechanisms during Cricket Paralysis Virus Infection ?  

PubMed Central

The dicistrovirus is a positive-strand single-stranded RNA virus that possesses two internal ribosome entry sites (IRES) that direct translation of distinct open reading frames encoding the viral structural and nonstructural proteins. Through an unusual mechanism, the intergenic region (IGR) IRES responsible for viral structural protein expression mimics a tRNA to directly recruit the ribosome and set the ribosome into translational elongation. In this study, we explored the mechanism of host translational shutoff in Drosophila S2 cells infected by the dicistrovirus, cricket paralysis virus (CrPV). CrPV infection of S2 cells results in host translational shutoff concomitant with an increase in viral protein synthesis. CrPV infection resulted in the dissociation of eukaryotic translation initiation factor 4G (eIF4G) and eIF4E early in infection and the induction of deIF2? phosphorylation at 3 h postinfection, which lags after the initial inhibition of host translation. Forced dephosphorylation of deIF2? by overexpression of dGADD34, which activates protein phosphatase I, did not prevent translational shutoff nor alter virus production, demonstrating that deIF2? phosphorylation is dispensable for host translational shutoff. However, premature induction of deIF2? phosphorylation by thapsigargin treatment early in infection reduced viral protein synthesis and replication. Finally, translation mediated by the 5? untranslated region (5?UTR) and the IGR IRES were resistant to impairment of eIF4F or eIF2 in translation extracts. These results support a model by which the alteration of the deIF4F complex contribute to the shutoff of host translation during CrPV infection, thereby promoting viral protein synthesis via the CrPV 5?UTR and IGR IRES.

Garrey, Julianne L.; Lee, Yun-Young; Au, Hilda H. T.; Bushell, Martin; Jan, Eric

2010-01-01

347

EFFECT OF SIALODACRYOADENITIS VIRUS INFECTION ON AXONAL REGENERATION  

PubMed Central

The effect of sialodacryoadenitis virus (SDAV) infection on axonal regeneration and functional recovery was investigated in male Lewis rats. Animals underwent unilateral tibial nerve transection, immediate repair, and treatment with either FK506 (treated) or control vehicle (untreated). Serial walking track analyses were performed to assess functional recovery. Nerves were harvested for morphometric analysis on postoperative day 18 after an SDAV outbreak occurred that affected the 12 experimental animals. Histomorphometry and walking track data were compared against 36 historical controls. Rats infected with SDAV demonstrated severely impaired axonal regeneration and diminished functional recovery. Total fiber counts, nerve density, and percent neural tissue were all significantly reduced in infected animals (P < 0.05). Active SDAV infection severely impaired nerve regeneration and negated the positive effect of FK506 on nerve regeneration in rats. Immunosuppressive risks must be weighed carefully against the potential neuroregenerative benefits in the treatment of peripheral nerve injuries.

YU, VIVIAN M.; MACKINNON, SUSAN E.; HUNTER, DANIEL A.; BRENNER, MICHAEL J.

2014-01-01

348

Epstein-barr virus infection with acute acalculous cholecystitis.  

PubMed

Acute acalculous cholecystitis (AAC) is an inflammation of the gallbladder in the absence of demonstrated stones. AAC is frequently associated with severe systemic inflammation. However, the exact etiology and pathogenesis of AAC still remain unclear. Acute infection with Epstein Barr virus (EBV) in childhood is usually aymptomatic, whereas it often presents as typical infectious mononucleosis symptoms such as fever, cervical lymphadenopathy, and hepatosplenomegaly. AAC may occur during the course of acute EBV infection, which is rarely encountered in the pediatric population. AAC complicating the course of a primary EBV infection is usually associated with a favorable outcome. Most of the patients recover without any surgical treatment. Therefore, the detection of EBV in AAC would be important for prediction of better prognosis. We describe the case of a 10-year-old child who presented with AAC during the course of primary EBV infection, the first in Korea, and review the relevant literature. PMID:24749090

Kim, Ahlee; Yang, Hye Ran; Moon, Jin Soo; Chang, Ju Young; Ko, Jae Sung

2014-03-01

349

Ovine Fetal Immune Response to Cache Valley Virus Infection  

PubMed Central

Cache Valley virus (CVV)-induced malformations have been previously reproduced in ovine fetuses. To evaluate the development of the antiviral response by the early, infected fetus, before the development of immunocompetency, ovine fetuses at 35 days of gestation were inoculated in utero with CVV and euthanized at 7, 10, 14, 21, and 28 days postinfection. The antiviral immune response in immature fetuses infected with CVV was evaluated. Gene expression associated with an innate, immune response was quantified by real-time quantitative PCR. The upregulated genes in infected fetuses included ISG15, Mx1, Mx2, IL-1, IL-6, TNF-?, TLR-7, and TLR-8. The amount of Mx1 protein, an interferon-stimulated GTPase capable of restricting growth of bunyaviruses, was elevated in the allantoic and amniotic fluid in infected fetuses. ISG15 protein expression was significantly increased in target tissues of infected animals. B lymphocytes and immunoglobulin-positive cells were detected in lymphoid tissues and in the meninges of infected animals. These results demonstrated that the infected ovine fetus is able to initiate an innate and adaptive immune response much earlier than previously known, which presumably contributes to viral clearance in infected animals.

Dorniak, Piotr; Filant, Justyna; Dunlap, Kathrin A.; Bazer, Fuller W.; de la Concha-Bermejillo, Andres; Welsh, Christabel Jane; Varner, Patricia

2013-01-01

350

Molecular Mechanisms Underlying Occult Hepatitis B Virus Infection  

PubMed Central

Summary: Chronic hepatitis B virus (HBV) infection is a complex clinical entity frequently associated with cirrhosis and hepatocellular carcinoma (HCC). The persistence of HBV genomes in the absence of detectable surface antigenemia is termed occult HBV infection. Mutations in the surface gene rendering HBsAg undetectable by commercial assays and inhibition of HBV by suppression of viral replication and viral proteins represent two fundamentally different mechanisms that lead to occult HBV infections. The molecular mechanisms underlying occult HBV infections, including recently identified mechanisms associated with the suppression of HBV replication and inhibition of HBV proteins, are reviewed in detail. The availability of highly sensitive molecular methods has led to increased detection of occult HBV infections in various clinical settings. The clinical relevance of occult HBV infection and the utility of appropriate diagnostic methods to detect occult HBV infection are discussed. The need for specific guidelines on the diagnosis and management of occult HBV infection is being increasingly recognized; the aspects of mechanistic studies that warrant further investigation are discussed in the final section.

Samal, Jasmine; Kandpal, Manish

2012-01-01

351

Molecular mechanisms underlying occult hepatitis B virus infection.  

PubMed

Chronic hepatitis B virus (HBV) infection is a complex clinical entity frequently associated with cirrhosis and hepatocellular carcinoma (HCC). The persistence of HBV genomes in the absence of detectable surface antigenemia is termed occult HBV infection. Mutations in the surface gene rendering HBsAg undetectable by commercial assays and inhibition of HBV by suppression of viral replication and viral proteins represent two fundamentally different mechanisms that lead to occult HBV infections. The molecular mechanisms underlying occult HBV infections, including recently identified mechanisms associated with the suppression of HBV replication and inhibition of HBV proteins, are reviewed in detail. The availability of highly sensitive molecular methods has led to increased detection of occult HBV infections in various clinical settings. The clinical relevance of occult HBV infection and the utility of appropriate diagnostic methods to detect occult HBV infection are discussed. The need for specific guidelines on the diagnosis and management of occult HBV infection is being increasingly recognized; the aspects of mechanistic studies that warrant further investigation are discussed in the final section. PMID:22232374

Samal, Jasmine; Kandpal, Manish; Vivekanandan, Perumal

2012-01-01

352

Treatment of liver transplant recipients who have chronic hepatitis C virus infection.  

PubMed

Chronic hepatitis C virus infection is the most common cause of chronic liver disease and indication for liver transplant in Western countries. Viral infection may recur after transplant in most patients. The diagnosis of histologic recurrence of hepatitis C virus infection after liver transplant may be difficult and may be confused with acute cellular graft rejection. Characteristics of the recipient, donor, virus, and transplant may be associated with disease progression. Treatment of hepatitis C virus infection has a positive effect on the outcome of liver transplant. There are 3 approaches used to minimize recurrent hepatitis C virus infection after liver transplant: antiviral therapy before transplant, antiviral preventive and preemptive treatment after transplant, and treatment of established reinfection. Protease inhibitors are being evaluated in patients who have severe hepatitis C virus recurrence after liver transplant. Liver graft survival is less frequent after revision transplant. Several new drugs currently are being evaluated in clinical trials for treatment of hepatitis C virus infection. PMID:24635788

Korkmaz, Murat

2014-03-01

353

Tomato bushy stunt virus (TBSV) infecting Lycopersicon esculentum.  

PubMed

Tomato bushy stunt virus (TBSV) was detected in tomato crop (Lycopersicon esculentum) in Egypt with characteristic mosaic leaf deformation, stunting, and bushy growth symptoms. TBSV infection was confirmed serologically by ELISA and calculated incidence was 25.5%. Basic physicochemical properties of a purified TBSV Egh isolate were identical to known properties of tombusviruses of isometric 30-nm diameter particles, 41-kDa coat protein and the genome of approximately 4800 nt. This is the first TBSV isolate reported in Egypt. Cloning and partial sequencing of the isolate showed that it is more closely related to TBSV-P and TBSV-Ch than TBSV-Nf and TBSV-S strains of the virus. However, it is distinct from the above strains and could be a new strain of the virus which further confirms the genetic diversity of tombusviruses. PMID:21138066

Hafez, El Sayed E; Saber, Ghada A; Fattouh, Faiza A

2010-01-01

354

Co-infections with hepatitis B and C viruses in human immunodeficiency virus-infected patients in Morocco.  

PubMed

Human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) are major public health concerns. We aimed to determine the prevalence of HBV and HCV infections among HIV-infected patients, and to identify the main circulating hepatitis strains in Morocco. The study was carried out in 503 HIV-infected patients. Our survey indicated that the prevalence of HIV/hepatitis co-infection was 10.6%; 5.2% of patients were HBV surface antigen positive, and 5.4% of patients were anti-HCV positive. Among the HBV surface antigen-positive group, HBV DNA sequencing identified exclusively genotype D (D1: 26.7%; D7: 73.3%) in accordance with what is found in the general population. In contrast, sequencing of HCV isolates produced an unusual subtype distribution with a decreasing order of prevalence: 1a, 3a (both 23.5%), 1b, 4a (both 17.6%), 1c (11.8%) and 6h (6%). PMID:23731409

Rebbani, K; Ouladlahsen, A; Bensghir, A; Akil, A; Lamdini, H; Issouf, H; Brahim, I; Kitab, B; Fakhir, F Z; Wakrim, L; Marhoum El Filali, K; Himmich, H; Ezzikouri, S; Benjelloun, S

2013-10-01

355

Axonal degeneration as a self-destructive defense mechanism against neurotropic virus infection  

PubMed Central

Theiler's murine encephalomyelitis virus (TMEV) and other neurotropic virus infections result in degeneration of each component of the neuron: apoptosis of the cell body, axonal (Wallerian) degeneration, and dendritic and synaptic pathology. In general, axonal degeneration is detrimental for hosts. However, axonal degeneration can be beneficial in the case of infection with neurotropic viruses that spread in the CNS using axonal transport. C57BL/WldS (WldS, Wallerian degeneration slow mutant) mice are protected from axonal degeneration. WldS mice infected with the neurovirulent GDVII strain of TMEV are more resistant to virus infection than wild-type mice, suggesting that axonal preservation contributes to the resistance. By contrast, infection with the less virulent Daniels strain of TMEV results in high levels of virus propagation in the CNS, suggesting that prolonged survival of axons in WldS mice favors virus spread. Thus, axonal degeneration might be a beneficial self-destruct mechanism that limits the spread of neurotropic viruses, in the case of less virulent virus infection. We hypothesize that neurons use ‘built-in’ self-destruct protection machinery (compartmental neurodegeneration) against neurotropic virus infection, since the CNS is an immunologically privileged site. Early induction of apoptosis in the neuronal cell body limits virus replication. Wallerian degeneration of the axon prevents axonal transport of virus. Dendritic and synaptic degeneration blocks virus transmission at synapses. Thus, the balance between neurodegeneration and virus propagation may be taken into account in the future design of neuroprotective therapy.

Tsunoda, Ikuo

2008-01-01

356

Indigenous West Nile virus infections in horses in Albania.  

PubMed

Serum samples collected from 167 equines of 12 districts in Albania were tested for West Nile virus-specific antibodies by enzyme-linked immunosorbent assay and virus neutralization assay, using WNV lineage 1 and 2. In addition, 95 bird serum samples from Albania and 29 horse samples from Kosovo were tested in ELISA. An overall seroprevalence rate of 22% was found in horses from Albania, whereas no specific antibodies were found in the equine samples from Kosovo and the bird samples. This is the first report indicating WNV infections in animals in Albania, and the first reported seroprevalence study conducted for Kosovo. These results provide evidence for widespread infections of WNV in Albania. PMID:24589101

Berxholi, K; Ziegler, U; Rexhepi, A; Schmidt, K; Mertens, M; Korro, K; Cuko, A; Angenvoort, J; Groschup, M H

2013-11-01

357

Hepatitis C Virus Infection Induces the Beta Interferon Signaling Pathway in Immortalized Human Hepatocytes  

Microsoft Academic Search

Beta interferon (IFN-) expression is triggered by double-stranded RNA, a common intermediate in the replication of many viruses including hepatitis C virus (HCV). The recent development of cell culture- grown HCV allowed us to analyze the IFN signaling pathway following virus infection. In this study, we have examined the IFN- signaling pathway following infection of immortalized human hepatocytes (IHH) with

Tatsuo Kanda; Robert Steele; Ranjit Ray; Ratna B. Ray

2007-01-01

358

Experimental infection of laying turkeys with Rhinotracheitis virus: Distribution of virus in the tissues and serological response  

Microsoft Academic Search

Twenty?four laying turkey hens shown to be free of antibodies to turkey rhinotracheitis virus were inoculated intranasally with an isolate of the virus. A mild respiratory disease developed between 5 and 9 days post infection (pi). Two birds were selected at random at intervals between days 1 and 20 pi, killed and tissues examined for the presence of virus. At

R. C. Jones; R. A. Williams; C. E. Savage; G. P. Wilding

1988-01-01

359

Diversity in Virus Populations from Genital Secretions and Peripheral Blood from Women Recently Infected with Human Immunodeficiency Virus Type 1  

Microsoft Academic Search

In order to develop a human immunodeficiency virus type 1 vaccine with global efficacy, it is important to evaluate the virus populations that are transmitted to individuals living in high-incidence areas. To determine the nature of the human immunodeficiency virus type 1 population transmitted to women during heterosexual contact, we examined the diversity of the proviral envelope gene in infected

MARY POSS; HAROLD L. MARTIN; JOAN K. KREISS; LAURA GRANVILLE; BHAVNA CHOHAN; PATRICK NYANGE; KISHORCHANDRA MANDALIYA; ANDJULIE OVERBAUGH

1995-01-01

360

Care of the Human Immunodeficiency Virus-Infected Menopausal Woman  

PubMed Central

More women than ever before are both Human Immunodeficiency Virus-infected and menopausal, because of increased survival and more frequent diagnosis in older women. Such a woman has the combined burden of her infection, its treatment, comorbid conditions, and aging. Thus she is at risk for a variety of problems such as disorders of bone mineral density and deficiencies in cognitive functioning. In addition to this, she experiences menopause in a unique fashion, with more symptoms and perhaps at an earlier age. The clinician caring for her must take a proactive approach to this multitude of factors that may affect her health and well-being.

Cejtin, Helen E.

2012-01-01

361

Impairment of monocytic function after influenza virus infection.  

PubMed Central

In order to analyze the immunosuppression associated with influenza virus infection, we investigated monocytic function in macrophage hybridoma cell lines 5 weeks after infection with two strains of influenza virus. Clones 30 and 63, chosen for stability in long-term culture, were infected with two strains of influenza virus, X-31 and PR-8. Uniform infection of both cell lines was confirmed by intracytoplasmic staining with the antihemagglutinin strain-specific monoclonal antibodies PY 102 and PY 206. One week after infection, clones 30 and 63 lost their ability to stimulate tetanus toxoid-specific major histocompatibility complex (MHC)-matched responder T cells. Coincident with the inability to stimulate MHC-matched T cells, there was diminished surface expression of class II MHC antigens and LFA-1-alpha and LFA-3 compared with that in uninfected cells: DR, 2.5 versus 10.6% (mean channel 0.3 versus 1.5); DQ, 1.6 versus 15.6% (mean channel 0.3 versus 3.0); DP, 5.0 versus 30.9% (mean channel 0.3 versus 2.0). LFA-1-alpha expression was reduced (13.1 versus 20.0%; mean channel 1.5 versus 2.0) while LFA-3 expression remained the same (22.2 versus 324%; mean channel 3.0 versus 3.3). Class I MHC surface antigen expression was unaltered. Cytokine secretion was also perturbed, as interleukin 1-alpha (IL-1-alpha) and IL-1-beta production was lost 1 week after infection. Production of IL-12 and IL-10 was unchanged, while IL-6 production was increased. The viability of the T cells cocultured with 63Flu was unaltered, demonstrating that the inability of the MHC-restricted T cells to proliferate in response to tetanus toxoid was not due to a toxic effect of 63Flu. Interestingly, other accessory functions, including the ability to support mitogen- and anti-CD3-mediated T-cell proliferation, remained intact. These data suggest that alteration of macrophage function relating to viral infection occurs at multiple levels and may contribute to the immunosuppression observed following influenza virus infection.

Louie, M; Yoo, J; Moran, T; Mayer, L; Sperber, K

1995-01-01

362

Lymphocytic Choriomeningitis Virus Infection in FVB Mouse Produces Hemorrhagic Disease  

PubMed Central

The viral family Arenaviridae includes a number of viruses that can cause hemorrhagic fever in humans. Arenavirus infection often involves multiple organs and can lead to capillary instability, impaired hemostasis, and death. Preclinical testing for development of antiviral or therapeutics is in part hampered due to a lack of an immunologically well-defined rodent model that exhibits similar acute hemorrhagic illness or sequelae compared to the human disease. We have identified the FVB mouse strain, which succumbs to a hemorrhagic fever-like illness when infected with lymphocytic choriomeningitis virus (LCMV). FVB mice infected with LCMV demonstrate high mortality associated with thrombocytopenia, hepatocellular and splenic necrosis, and cutaneous hemorrhage. Investigation of inflammatory mediators revealed increased IFN-?, IL-6 and IL-17, along with increased chemokine production, at early times after LCMV infection, which suggests that a viral-induced host immune response is the cause of the pathology. Depletion of T cells at time of infection prevented mortality in all treated animals. Antisense-targeted reduction of IL-17 cytokine responsiveness provided significant protection from hemorrhagic pathology. F1 mice derived from FVB×C57BL/6 mating exhibit disease signs and mortality concomitant with the FVB challenged mice, extending this model to more widely available immunological tools. This report offers a novel animal model for arenavirus research and pre-clinical therapeutic testing.

Schnell, Frederick J.; Sundholm, Sarah; Crumley, Stacy; Iversen, Patrick L.; Mourich, Dan V.

2012-01-01

363

Recurrent herpes simplex virus ocular infection: epidemiological and clinical features.  

PubMed

The epidemiological and clinical features of recurrent herpes simplex virus ocular infection (RHSV) were studied. Of 108 patients with primary herpes simplex virus ocular infection (PHSV) who were followed up for two to 15 years 35 (32%) suffered one or more recurrent attacks. The recurrence rate was significantly higher in patients under 20 years of age, but there was no significant difference between recurrence rates in males and females. Of 35 patients with RHSV 17 (49%) had one recurrent attack, 14 (40%) had between two and five, and four (11%) had between six and 15 attacks. The mean time interval between PHSV and the first four RHSV attacks was 10 months, and was shorter in subsequent attacks. The duration and severity of RHSV were reduced in successive recurrences. Patients with more severe conjunctivitis and lid lesions during PHSV ocular infection had a higher incidence of recurrent infection. The severity of the corneal signs in PHSV had no influence on the incidence of recurrent infection. Several clinical forms of RHSV were observed. Conjunctivitis associated with lid lesions was observed in 29 (83%) patients. In six (17%) patients the disease presented as an acute follicular conjunctivitis without characteristic lid or corneal lesions. Dendritic ulcer was found in three (9%) patients, and in one of them it was associated with a disciform keratitis. A chronic blepharoconjunctivitis developed in eight (23%) patients. The epidemiological and clinical features of RHSV were compared with those of PHSV. PMID:3663560

Wishart, M S; Darougar, S; Viswalingam, N D

1987-09-01

364

Lactoferrin inhibits hepatitis B virus infection in cultured human hepatocytes.  

PubMed

We recently reported that lactoferrin (LF), a milk protein belonging to the iron transporter family, inhibits hepatitis C virus (HCV) infection in cultured human hepatocytes (PH5CH8) and that the interaction of LF with HCV is responsible for this inhibitory effect. As PH5CH8 cells were found to be a human hepatocyte line susceptible to hepatitis B virus (HBV) infection, we therefore examined if LF could effectively prevent HBV infection in PH5CH8 cells. Preincubation of the cell with bovine LF (bLF) or human LF (hLF) was required to prevent HBV infection of cells, and preincubation of HBV with bLF or hLF had no inhibitory effect on HBV infection. We further found that bovine transferrin, casein, and lactoalbumin had no anti-HBV activity. Our findings suggest that the interaction of LF with cells was important for its inhibitory effect, and that LF may well be among the candidates for an anti-HBV reagent that could prove effective in the treatment of patients with chronic hepatitis. PMID:12393024

Hara, Koji; Ikeda, Masanori; Saito, Satoru; Matsumoto, Shuhei; Numata, Kazushi; Kato, Nobuyuki; Tanaka, Katsuaki; Sekihara, Hisahiko

2002-11-01

365

Hepatitis B and hepatitis delta virus infection in South America.  

PubMed Central

About 100,000 cases of acute hepatitis B virus (HBV) infection occur annually in South America. The overall prevalence of HBV infection in low risk populations ranges from 6.7% to 41%, while hepatitis B surface antigen (HBsAg) rates range from 0.4% to 13%. In high endemicity aboriginal or rural populations, perinatal transmission may play a major part in the spread of HBV. In urban populations, however, horizontal transmission, probably by sexual contact, is the predominant mode of spread, with higher rates of HBV positivity in lower socioeconomic groups. High risk populations such as health care workers and haemodialysis patients show higher rates of HBV infection than comparable populations elsewhere. The risk of posttransfusion hepatitis B remains high in some areas. Concomitant HBV infection may accelerate the chronic liver disease seen in decompensated hepatosplenic schistosomiasis. In the north, the prevalence of hepatitis delta virus (HDV) infection ranks among the highest in the world. In the south, the problem appears negligible although it is increasing within high risk urban communities. HDV superinfection has been the cause of large outbreaks of fulminant hepatitis. The cost of comprehensive or mass vaccination programmes remains unaffordable for most South American countries. Less expensive alternatives such as low dose intradermal schedules of immunisation have been used with success in selected adult subjects.

Torres, J R

1996-01-01

366

Innate immune responses in respiratory syncytial virus infections.  

PubMed

Respiratory syncytial virus (RSV) is the most important viral respiratory pathogen of early life. Studies of the immune response in general (and the innate response in particular) to this agent are of interest for a number of reasons. First, severe forms of illness may be a result of enhanced immunologic responsiveness to viral constituents at the time of infection. Secondly, the immune response to RSV may consist principally of innate immune responses at the time of maximum severity of illness. Third, RSV infection in infancy may be linked via immune mechanisms to the development of childhood wheezing. Finally there are no meaningfully effective forms of therapy for RSV infection, and elucidation of the immune response may suggest new therapeutic approaches. This review will summarize our current knowledge of innate immune responses to RSV infection. Specifically we will review early interactions of the virus with surfactant proteins and Toll-like receptors, chemokine release from infected cells, cytokine release from activated inflammatory cells, activation of neuroimmune pathways, generation of dendritic cells, the release of soluble mediators of airway obstruction, and genetic polymorphisms associated with RSV-related illness. PMID:15279701

Krishnan, Subramaniam; Halonen, Marilyn; Welliver, Robert C

2004-01-01

367

Performance of virus isolation and Directigen® Flu A to detect influenza A virus in experimental human infection  

Microsoft Academic Search

Background: few data exist to assess the sensitivity of different specimen types for viral detection during the course of influenza virus infection. Objectives: this study assessed the relationships between quantitative influenza A virus replication and antigen detectability by the enzyme immunosorbent assay (EIA) Directigen® Flu A in different type of samples during experimental human infection. Study design: fourteen volunteers were

Laurent Kaiser; Marcus S Briones; Frederick G Hayden

1999-01-01

368

Altered plasma concentrations of sex hormones in cats infected by feline immunodeficiency virus and\\/or feline leukemia virus  

Microsoft Academic Search

It has been suggested that gender differences may affect HIV infection in humans and that they may be related to fluctuations in sex hormones concentration. The different percentage of male and female cats that has been observed to be infected by feline leukemia virus (FeLV) and\\/or feline immunodeficiency virus (FIV) has been traditionally explained through the transmission mechanisms of both

G. Tejerizo; A. Doménech; J.-C. Illera; G. Silván; E. Gómez-Lucía

369

Fine Structure of Cellular Inclusions in Measles Virus Infections  

PubMed Central

Cells which are infected with measles virus have been known for some time to contain inclusion material that is distinguishable from normal cellular components by application of traditional staining methods and observation in the light microscope. The fine structure of the inclusion material contained in HeLa cells infected with Edmonston strain of measles virus has been examined in the electron microscope. Two steps have been found necessary in this study: (1) the recognition by phase-contrast microscopy of the living cell of bodies that are defined as inclusion material when the cells are classically stained; and (2) the recognition in the electron microscope of inclusion-body material that had previously been identified in the living cell. The fine structure of the nuclear and cytoplasmic inclusion material in osmium-treated cells was found to consist mainly of randomly arrayed filaments of low electron density. Dense, highly ordered arrays of filaments were found near the center of the nuclear inclusions, sometimes as a two-dimensional, nearly orthogonal arrangement. If the size of the measles virus is taken to be around 100 mµ in diameter, the strands seen in the inclusions cannot be fully formed virus.

Kallman, Frances; Adams, John M.; Williams, Robley C.; Imagawa, David T.

1959-01-01

370

Low-dose interferon-? treatment for feline immunodeficiency virus infection  

Microsoft Academic Search

Feline immunodeficiency virus sustains an AIDS-like syndrome in cats, which is considered a relevant model for human AIDS. Under precise enrolment requirements, 30 naturally infected cats showing overt disease were included in a trial of low-dose, oral human interferon-? treatment. Twenty-four of them received 10IU\\/Kg of human interferon-? and 6 placebo only on a daily basis under veterinary supervision. The

E. Pedretti; B. Passeri; M. Amadori; P. Isola; P. Di Pede; A. Telera; R. Vescovini; F. Quintavalla; M. Pistello

2006-01-01

371

Epidemiology of hepatitis C virus infection in American veterans  

Microsoft Academic Search

OBJECTIVE:This study reports the findings of hepatitis C virus (HCV) infection in a large Department of Veterans Affairs Health Care System in suburban Northern California.METHODS:All veterans who had anti-HCV (EIA II) tested during a 6-yr period (7\\/92 to 6\\/98) were included in this study. To estimate the seroprevalence of anti-HCV among our population, 126 consecutive bloodborne pathogen exposure accidents were

Ramsey C. Cheung

2000-01-01

372

Prophylaxis against recurrent hepatitis B virus infection after liver transplantation  

Microsoft Academic Search

Over the past two decades, there have been significant improvements in the outcomes of liver transplantation for all indications.\\u000a Liver transplantation for hepatitis B virus (HBV) infection, once considered a contraindication to transplantation, now achieves\\u000a survival rates of 91% at 1 year, 81% at 5 years, and 73% at 10 years. This improvement in outcome has occurred largely with\\u000a the

Michael P. Curry; Nezam H. Afdhal

2007-01-01

373

Screening for Hepatitis C Virus in Human Immunodeficiency Virus-Infected Individuals  

PubMed Central

Immunosuppression from human immunodeficiency virus (HIV) may impair antibody formation, and false-negative hepatitis C virus antibody (anti-HCV) tests have been reported in individuals coinfected with HIV and HCV. It is unknown if the frequency of false-negative tests is sufficiently high to change screening recommendations in this setting. Thus, the prevalence of false-negative results for anti-HCV by third-generation tests was determined with samples from HIV-infected individuals. Sera from 559 HIV-infected and 944 HIV-negative prospectively followed injection drug users were tested for anti-HCV by a third-generation enzyme immunoassay and for HCV RNA by using a branched DNA assay and the HCV COBAS AMPLICOR system. Of 559 HIV-infected participants, 547 (97.8%) were anti-HCV positive. One of the remaining 12 anti-HCV-negative participants was HCV RNA positive, and she later developed detectable anti-HCV. Of the 944 HIV-negative participants, 825 (87.4%) were anti-HCV positive. One of the remaining 119 anti-HCV-negative participants was HCV RNA positive, and she also developed detectable anti-HCV at a later visit. These data indicate that HIV infection does not alter the approach to hepatitis C virus screening, which should be performed with third-generation assays for anti-HCV unless acute infection is suspected.

Thio, Chloe L.; Nolt, Karen R.; Astemborski, Jacquie; Vlahov, David; Nelson, Kenrad E.; Thomas, David L.

2000-01-01

374

Occult Hepatitis B Virus Infection in Chacma Baboons, South Africa  

PubMed Central

During previous studies of susceptibility to hepatitis B virus (HBV) infection, HBV DNA was detected in 2/6 wild-caught baboons. In the present study, HBV DNA was amplified from 15/69 wild-caught baboons. All animals were negative for HBV surface antigen and antibody against HBV core antigen. Liver tissue from 1 baboon was immunohistochemically negative for HBV surface antigen but positive for HBV core antigen. The complete HBV genome of an isolate from this liver clustered with subgenotype A2. Reverse transcription PCR of liver RNA amplified virus precore and surface protein genes, indicating replication of virus in baboon liver tissue. Four experimentally naive baboons were injected with serum from HBV DNA–positive baboons. These 4 baboons showed transient seroconversion, and HBV DNA was amplified from serum at various times after infection. The presence of HBV DNA at relatively low levels and in the absence of serologic markers in the baboon, a nonhuman primate, indicates an occult infection.

Dickens, Caroline; Kew, Michael C.; Purcell, Robert H.

2013-01-01

375

Multiplicity of Scrapie virus in infected mouse spleen cells in vivo.  

PubMed

Subpopulations of spleen cells from scrapie virus-infected mice were used to determine the average virus content of infected cells in vivo at a time when virus was rapidly increasing in titer in lymphoreticular tissues. Comparison of the mean lethal doses of lysed to intact cells indicated averages of 2 to 6 infectious units per infected cell. In another experiment, preparations of cytoplasmic nucleic acids extracted from spleen cells of infected mice had no detectable infectivity, which suggests that the transmissible form of the virus is not a free nucleic acid. PMID:4197750

Lavelle, G C

1973-06-01

376

Multiplicity of Scrapie Virus in Infected Mouse Spleen Cells In Vivo  

PubMed Central

Subpopulations of spleen cells from scrapie virus-infected mice were used to determine the average virus content of infected cells in vivo at a time when virus was rapidly increasing in titer in lymphoreticular tissues. Comparison of the mean lethal doses of lysed to intact cells indicated averages of 2 to 6 infectious units per infected cell. In another experiment, preparations of cytoplasmic nucleic acids extracted from spleen cells of infected mice had no detectable infectivity, which suggests that the transmissible form of the virus is not a free nucleic acid. Images

Lavelle, G. C.

1973-01-01

377

Changes in the Ribosomes Extracted from Mung Beans Infected with a Strain of Tobacco Mosaic Virus  

Microsoft Academic Search

SUMMARY Virus infection causes an increase in the quantity of ribosomes extracted from the hypocotyls of Mung beans. Though this increase is not confined to a particular size of ribosome, presumptive virus messenger RNA is associated predominantly with polyribosomes composed of nine or more monoribosomes. METHODS Virus. A virus from cowpea (CMV; Lister & Thresh, I955) which has been shown

D. McCarthy; B. C. Jarvis; B. J. Thomas

1970-01-01

378

Duck hepatitis B virus (DHBV) infection in Indian domestic ducks: A pilot study  

Microsoft Academic Search

One hundred and two apparently healthy Indian domestic ducks from the Poultry Research Station, Madras were screened for duck hepatitis B virus (DHBV) infection by; 1. screening for the duck hepatitis B virus surface antigen (DHBsAg) in their sera using hepatitis B virus (HBV) reagents, 2. screening for DHBsAg using specific duck hepatitis B virus (DHBV) reagents and 3. demonstration

G. Sridhar; T. Valliammai; C. S. Varalakshmi; K. Udayasankar; M. Panchanadam; J. Ramakrishna; K. Venkatesh Gopal; Kunthala Jayaraman; S. P. Thyagarajan

1993-01-01

379

Incidence of hepatitis C virus infection among injection drug users during an outbreak of HIV infection  

Microsoft Academic Search

Background: Beginning in 1994, Vancouver experienced an explosive outbreak of HIV infection among injection drug users (IDUs). The objectives of this study were to measure the prevalence and incidence of hepatitis C virus (HCV) infec- tion in this context and to examine factors associated with HCV seroconversion among IDUs. Methods: IDUs recruited through a study site and street outreach completed

David M. Patrick; Mark W. Tyndall; Peter G. A. Cornelisse; Kathy Li; Chris H. Sherlock; Michael L. Rekart; Steffanie A. Strathdee; Sue L. Currie; Martin T. Schechter; Michael V. O'Shaughnessy

380

Hepatitis B Virus Infection and Immunizations among Asian American College Students: Infection, Exposure, and Immunity Rates  

ERIC Educational Resources Information Center

Objectives: To evaluate the prevalence of hepatitis B virus (HBV) infection, exposure, and immunity among Asian American college students as a basis for evaluating HBV screening and vaccination policy. Participants and Methods: Self-identified Asian American college students aged 18 years or older were examined. Serological tests of HBV surface…

Lee, Haeok; Kiang, Peter; Watanabe, Paul; Halon, Patricia; Shi, Ling; Church, Daniel R.

2013-01-01

381

Human febrile illness caused by encephalomyocarditis virus infection, Peru.  

PubMed

Etiologic studies of acute febrile disease were conducted in sites across South America, including Cusco and Iquitos, Peru. Patients' clinical signs and symptoms were recorded, and acute- and convalescent-phase serum samples were obtained for serologic examination and virus isolation in Vero E6 and C6/36 cells. Virus isolated in Vero E6 cells was identified as encephalomyocarditis virus (EMCV) by electron microscopy and by subsequent molecular diagnostic testing of samples from 2 febrile patients with nausea, headache, and dyspnea. The virus was recovered from acute-phase serum samples from both case-patients and identified with cardiovirus-specific reverse transcription-PCR and sequencing. Serum samples from case-patient 1 showed cardiovirus antibody by immunoglobulin M ELISA (acute phase <8, convalescent phase >1,024) and by neutralization assay (acute phase <10, convalescent phase >1,280). Serum samples from case-patient 2 did not contain antibodies detectable by either assay. Detection of virus in serum strongly supports a role for EMCV in human infection and febrile illness. PMID:19331761

Oberste, M Steven; Gotuzzo, Eduardo; Blair, Patrick; Nix, W Allan; Ksiazek, Thomas G; Comer, James A; Rollin, Pierre; Goldsmith, Cynthia S; Olson, James; Kochel, Tadeusz J

2009-04-01

382

Endogenous viral genes influence infection with avian leukosis virus.  

PubMed

The influence of endogenous viral (ev) genes on avian leukosis virus (ALV) infection was studied in ALV-free white leghorn chickens exposed to chicks from ALV shedding dams. The study included four lines, each segregating for one ev gene, one line free of ev genes, and four commercial stocks segregating for a number of ev genes. Genes ev12 and ev21 that produce the complete endogenous virus were associated with significant reductions in antibody response to ALV. In commercial stocks with ev21 in all birds, both antibody response and ALV in oviducts were significantly influenced by the genomic background (stock). In one commercial stock, 37.6% of 133 birds with ev21 and only 5.8% of 120 birds without the gene were test-positive for virus in their oviducts at 180 days of age. No such differences were associated with ev1, ev3 or ev6 that do not produce complete endogenous virus. Thus, virus-producing ev genes were a predisposing factor for shedding ALV. PMID:18645822

Gavora, J S; Spencer, J L; Benkel, B; Gagnon, C; Emsley, A; Kulenkamp, A

1995-12-01

383

Primary influenza A virus infection induces cross-protective immunity against a lethal infection with a heterosubtypic virus strain in mice.  

PubMed

In order to assess the level of protection against a lethal influenza virus infection provided by a primary infection with a virus strain of another subtype, C57BL/6 mice were infected with the sublethal influenza virus X-31 (H3N2) and subsequently challenged with the lethal strain A/PR/8/34 (H1N1). The outcome of the challenge infection was compared with that in mice that did not experience an infection with influenza virus X-31 prior to the challenge infection. The X-31 experienced mice cleared the infection with influenza virus A/PR/8/34 in an accelerated fashion, displayed less clinical signs and a reduction of lesions in the lungs resulting in improved survival rates of these mice compared to the naive mice. The improved outcome of the challenge infection with influenza virus A/PR/8/34 in the X-31 experienced mice correlated with priming for anamnestic virus-specific CD8(+) cytotoxic T lymphocyte (CTL) responses as was demonstrated by the detection of CTL specific for the H-2D(b) restricted NP(366-374) epitope that was shared by the influenza viruses X-31 and A/PR/8/34. Thus previous exposure to influenza A viruses affords partial protection against infection in the absence of virus-neutralizing antibodies specific for the hemagglutinin and the neuraminidase. The implications of these observations are discussed in the light of the current pandemic threat and development of vaccines that aim at the induction of virus-specific CTL. PMID:17005299

Kreijtz, J H C M; Bodewes, R; van Amerongen, G; Kuiken, T; Fouchier, R A M; Osterhaus, A D M E; Rimmelzwaan, G F

2007-01-01

384

A Human Lung Xenograft Mouse Model of Nipah Virus Infection  

PubMed Central

Nipah virus (NiV) is a member of the genus Henipavirus (family Paramyxoviridae) that causes severe and often lethal respiratory illness and encephalitis in humans with high mortality rates (up to 92%). NiV can cause Acute Lung Injury (ALI) in humans, and human-to-human transmission has been observed in recent outbreaks of NiV. While the exact route of transmission to humans is not known, we have previously shown that NiV can efficiently infect human respiratory epithelial cells. The molecular mechanisms of NiV-associated ALI in the human respiratory tract are unknown. Thus, there is an urgent need for models of henipavirus infection of the human respiratory tract to study the pathogenesis and understand the host responses. Here, we describe a novel human lung xenograft model in mice to study the pathogenesis of NiV. Following transplantation, human fetal lung xenografts rapidly graft and develop mature structures of adult lungs including cartilage, vascular vessels, ciliated pseudostratified columnar epithelium, and primitive “air” spaces filled with mucus and lined by cuboidal to flat epithelium. Following infection, NiV grows to high titers (107 TCID50/gram lung tissue) as early as 3 days post infection (pi). NiV targets both the endothelium as well as respiratory epithelium in the human lung tissues, and results in syncytia formation. NiV infection in the human lung results in the production of several cytokines and chemokines including IL-6, IP-10, eotaxin, G-CSF and GM-CSF on days 5 and 7 pi. In conclusion, this study demonstrates that NiV can replicate to high titers in a novel in vivo model of the human respiratory tract, resulting in a robust inflammatory response, which is known to be associated with ALI. This model will facilitate progress in the fundamental understanding of henipavirus pathogenesis and virus-host interactions; it will also provide biologically relevant models for other respiratory viruses.

Borisevich, Viktoriya; Goez, Yenny; Rockx, Barry

2014-01-01

385

Spontaneous clearance of childhood hepatitis C virus infection.  

PubMed

To describe the spontaneous clearance rate of childhood hepatitis C virus (HCV) infection, to determine whether route of transmission affects the clearance rate and to identify other predictors of clearance. Children with chronic hepatitis C were identified between 1990 and 2001. The rate of spontaneous clearance (defined as >or=2 positive anti-HCV antibody test but negative HCV RNA) was calculated using survival analysis. Univariate and multivariate predictor variables [route of transmission, age at infection, age at last follow-up, alanine aminotransferase (ALT) and gender] for clearance were evaluated. Of 157 patients, 28% of children cleared infection (34 transfusional and 10 nontransfusional cases). The 123 transfusional cases were older at time of infection and at follow-up, compared with the 34 nontransfusional cases. Younger age at follow-up (p < 0.0001) and normal ALT levels (p < 0.0001) favoured clearance. Among cases of neonatal infection, 25% demonstrated spontaneous clearance by 7.3 years. The rate of spontaneous clearance of childhood HCV infection was comparable between transfusional and nontransfusional cases. If clearance occurs, it tends to occur early in infection, at a younger age. PMID:17927616

Yeung, L T F; To, T; King, S M; Roberts, E A

2007-11-01

386

Persistent infection of normal mice with human immunodeficiency virus.  

PubMed Central

In this article, we report the establishment of persistent HIV type 1 infection of normal Swiss mice after a single intraperitoneal injection with high-producing HIV-infected U937 cells. Anti-HIV antibodies were found more than 500 days after the original injection, and p24 antigenemia was detected in approximately 50% of the mice. By polymerase chain reaction (PCR) techniques, HIV-specific gag and env sequences were detected in DNA samples from peripheral blood mononuclear cells (PBMC) and peritoneal cells of seropositive mice 300 to 500 days after inoculation with HIV-infected cells. These DNA samples did not contain human DNA sequences, as determined by PCR analysis using primers and the probe for the HLA-DQ alpha gene. Low levels of p24 and detectable human reverse transcriptase activity were found in cultures of PBMC and peritoneal macrophages. Cocultivation of PBMC, peritoneal cells, and spleen cells with human uninfected U937 or CEM (a T lymphoma cell line) cells resulted in HIV infection of the target cells, as determined by PCR analysis and/or p24 assays. The intravenous injection of untreated Swiss mice with the PBMC from PCR-positive mice resulted in the development of an increasing antibody response to HIV in the recipient animals. Together these results indicate that cells from seropositive Swiss mice were persistently infected with HIV and were capable of producing infectious virus. The development of persistent HIV infection in an immunocompetent mouse may represent the starting point for further studies aimed at defining the host mechanisms involved in the restriction of virus replication, defining the pathogenesis of HIV infection, and testing antiviral compounds and vaccines. Images

Locardi, C; Puddu, P; Ferrantini, M; Parlanti, E; Sestili, P; Varano, F; Belardelli, F

1992-01-01

387

Dengue virus infection induces autophagy: an in vivo study  

PubMed Central

Background We and others have reported that autophagy is induced by dengue viruses (DVs) in various cell lines, and that it plays a supportive role in DV replication. This study intended to clarify whether DV infection could induce autophagy in vivo. Furthermore, the effect of DV induced autophagy on viral replication and DV-related pathogenesis was investigated. Results and conclusions The physiopathological parameters were evaluated after DV2 was intracranially injected into 6-day-old ICR suckling mice. Autophagy-related markers were monitored by immunohistochemical/immunofluorescent staining and Western blotting. Double-membrane autophagic vesicles were investigated by transmission-electron-microscopy. DV non-structural-protein-1 (NS1) expression (indicating DV infection) was detected in the cerebrum, medulla and midbrain of the infected mice. In these infected tissues, increased LC3 puncta formation, LC3-II expression, double-membrane autophagosome-like vesicles (autophagosome), amphisome, and decreased p62 accumulation were observed, indicating that DV2 induces the autophagic progression in vivo. Amphisome formation was demonstrated by colocalization of DV2-NS1 protein or LC3 puncta and mannose-6-phosphate receptor (MPR, endosome marker) in DV2-infected brain tissues. We further manipulated DV-induced autophagy by the inducer rapamycin and the inhibitor 3-methyladenine (3MA), which accordingly promoted or suppressed the disease symptoms and virus load in the brain of the infected mice. We demonstrated that DV2 infection of the suckling mice induces autophagy, which plays a promoting role in DV replication and pathogenesis.

2013-01-01

388

TT virus infection in patients on peritoneal dialysis in Taiwan.  

PubMed

Many studies have reported the prevalence of transfusion-transmitted virus (TTV) infection in hemodialysis patients, but few reports studied the prevalence of TTV infection in peritoneal dialysis patients. In this study, we determined the prevalence of TTV in a peritoneal dialysis population in Taiwan and related its prevalence with history of blood transfusion, serum hepatitis B surface antigen (HBsAg), antibody to hepatitis C virus (anti-HCV), and serum aminotransferases (AST and ALT) levels. Serum samples from 47 peritoneal dialysis patients and a control group of 43 patients at health examination were studied for TTV viremia by using polymerase chain reaction. The rate of blood transfusion exposure (p < 0.0001), female gender (p = 0.001), younger age (p = 0.0014), and serum AST level (p = 0.012) were significantly higher in peritoneal dialysis patients. The prevalence of TTV viremia was not significantly different between peritoneal dialysis patients and the control group (23.4% vs. 37.2%). TTV infection was not associated with evident liver diseases in peritoneal dialysis patients, and the infection rate was not different between automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD) patients. There was no statistically significant association between TTV infection and age, gender, transfusion history, duration of peritoneal dialysis, AST level, ALT level, HBsAg, or anti-HCV seropositivity in peritoneal dialysis patients. Our results suggest that TTV infection is not associated with evident liver diseases, and there is no difference between TTV infection in healthy individuals and peritoneal dialysis patients. TTV transmission probably occurs via routes unrelated to peritoneal dialysis. PMID:17654317

Hsu, Bang-Gee; Wang, Li-Yu; Hu, Chi-Tan; Wang, Chih-Hsien; Fang, Te-Chao; Lin, Hans Hsienhong

2007-01-01

389

Infections  

MedlinePLUS

... Infections Warts West Nile Virus What Is "PANS"? Whooping Cough (Pertussis) Yersiniosis Ear Infections Can Chronic Ear Infections Cause ... Immunizations: Chickenpox Vaccine Your Child's Immunizations: Diphtheria, Tetanus & Pertussis Vaccine (DTaP) Your Child's Immunizations: Hepatitis A Vaccine ( ...

390

Establishment of infection by spleen necrosis virus: inhibition in stationary cells and the role of secondary infection.  

PubMed Central

The relationship of two early events in the establishment of infection by avian retroviruses, the inhibition of viral DNA synthesis in stationary avian cells and the secondary infection which occurs after infection of replicating cells, was investigated. When neutralizing antibody to spleen necrosis virus was used to prevent secondary infection, the amount of unintegrated linear spleen necrosis virus DNA detected was much lower in infected stationary cells than in infected replicating cells. The amount of unintegrated linear spleen necrosis virus DNA in stationary cells was less than one copy per cell even at high multiplicities of infection. Viral DNA synthesis resumed after stimulation of the cells to replicate. The time of this viral DNA synthesis was closely correlated with renewed cellular DNA synthesis. In addition, blocking secondary infection of replicating cells prevented the rate of virus production from reaching the high levels usually associated with a normal productive infection by SNV. Virus production increased if secondary infection was allowed. However, this rise in virus production was not proportional to the amounts of viral DNA integrated after secondary infection. Images

Chen, I S; Temin, H M

1982-01-01

391

Activation of the Murine Sarcoma Virus Genome After Infection with the Murine Leukemia Virus as Determined by Cell Agglutination  

PubMed Central

Non-virus-producing NIH/3T3 cells transformed by the murine sarcoma virus are agglutinated by conconavalin A to the same low level as normal NIH/3T3 cells. Infection with the murine leukemia virus greatly increases the agglutination of transformed cells but not that of normal cells. These data suggest that the morphological expression of cell transformation and the surface alterations associated with increased cell agglutination are controlled by the expressions of different sarcoma virus genes.

Salzberg, Samuel; Green, Maurice

1974-01-01

392

Medical management of human immunodeficiency virus infection  

PubMed Central

The human immunodeficiency virus (HIV)/ acquired immune deficiency syndrome (AIDS) pandemic has pervasive effects on culture, economics, policy, and human development. All organs can be affected by complications of HIV/AIDS, including the eye. When sufficient resources are available and widespread antiretroviral resistance does not exist, the four available classes of antiretroviral agents - nucleoside/ nucleotide reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitors, and fusion inhibitors - can be combined to provide highly active antiretroviral therapy (HAART). For many (not all) patients, HAART converts an inexorably fatal disease into a chronic disease with a fairly good prognosis. Use of HAART often induces partial immune recovery, which has predominantly beneficial effects on ocular complications of AIDS. However, HAART-induced immune recovery sometimes results in immune recovery inflammatory syndromes, such as immune recovery uveitis. Use of HAART is the single most useful intervention for most patients with ocular complications of AIDS. However, specific ocular therapy is also critical to avoid blindness in the early months before immune recovery can occur, or if HAART is unavailable. Increasing availability of HAART worldwide shows great promise to alleviate one of the world?s greatest plagues. However, predictable secular trends in the AIDS epidemic make it likely that the number of cases of ocular complications of AIDS will increase substantially before they decrease. Ophthalmologists worldwide should be familiar with the diagnosis and management of cytomegalovirus retinitis - the most common ocular complication of AIDS - and should establish partnerships with physicians who are able to provide HAART. Research is needed to determine the optimal approach for managing cytomegalovirus retinitis in resource- constrained settings.

2008-01-01

393

Domestic cats are susceptible to infection with low pathogenic avian influenza viruses from shorebirds.  

PubMed

Domestic cats are susceptible to infection with highly pathogenic avian influenza virus H5N1, resulting in pneumonia and in some cases, systemic spread with lesions in multiple organ systems. Recent transmission of the 2009 pandemic H1N1 influenza virus from humans to cats also resulted in severe pneumonia in cats. Data regarding the susceptibility of cats to other influenza viruses is minimal, especially regarding susceptibility to low pathogenic avian influenza viruses from wild birds, the reservoir host. In this study, the authors infected 5-month-old cats using 2 different North American shorebird avian influenza viruses (H1N9 and H6N4 subtypes), 3 cats per virus, with the goal of expanding the understanding of avian influenza virus infections in this species. These viruses replicated in inoculated cats based on virus isolation from the pharynx in 2 cats, virus isolation from the lung of 1 cat, and antigen presence in the lung via immunohistochemistry in 2 cats. There was also seroconversion and lesions of patchy bronchointerstitial pneumonia in all of the cats. Infection in the cats did not result in clinical disease and led to variable pharyngeal viral shedding with only 1 of the viruses; virus was localized in the alveolar epithelium via immunohistochemistry. These findings demonstrate the capacity of wild bird influenza viruses to infect cats, and further investigation is warranted into the pathogenesis of these viruses in cats from both a veterinary medical and public health perspective. PMID:22732359

Driskell, E A; Jones, C A; Berghaus, R D; Stallknecht, D E; Howerth, E W; Tompkins, S M

2013-01-01

394

Bovine immunodeficiency virus produces a transient viraemic phase soon after infection in Bos javanicus  

Microsoft Academic Search

Infection of Bali cattle (Bos javanicus) in Indonesia with a non-pathogenic bovine lentivirus similar to Bovine immunodeficiency virus (BIV) is suspected but efforts to detect the virus have been unsuccessful. To define the kinetics of BIV infection in Bali cattle, 13 were infected with the R-29 strain of BIV and monitored for 60 days. No clinical effects were detected. Proviral

Tegan McNab; Moira Desport; W. Masa Tenaya; Nining Hartaningsih; Graham E. Wilcox

2010-01-01

395

Cotton rats ( Sigmodon hispidus): an animal model to study the pathogenesis of measles virus infection  

Microsoft Academic Search

Measles is still the most lethal infectious disease of infants worldwide. In spite of research efforts, two major problems associated with measles virus (MV) infection have not been resolved. One is the marked immune suppression leading to subsequent (often lethal) opportunistic infections and the second is waning of maternal antibodies which do not protect against wild type virus infection any

Stefan Niewiesk

1999-01-01

396

Borna Disease Virus-Induced Neurological Disorder in Mice: Infection of Neonates Results in Immunopathology  

Microsoft Academic Search

Borna disease virus (BDV) is a neurotropic nonsegmented negative-stranded RNA virus that persistently infects warm-blooded animals. In horses and other natural animal hosts, infections with BDV cause menin- goencephalitis and behavioral disturbances. Experimental infection of adult mice takes a nonsymptomatic course, an observation previously believed to indicate that this animal species is not suitable for pathogenesis studies. We now demonstrate

WIEBKE HALLENSLEBEN; MARTIN SCHWEMMLE; JURGEN HAUSMANN; LOTHAR STITZ; BENEDIKT VOLK; AXEL PAGENSTECHER; PETER STAEHELI

1998-01-01

397

Role of Natural Killer Cells in Innate Protection Against Lethal Ebola Virus Infection.  

National Technical Information Service (NTIS)

Ebola virus is a highly lethal human pathogen and is rapidly driving many wild primate populations toward extinction. Several lines of evidence suggest that innate, nonspecific host factors are potentially critical for survival after Ebola virus infection...

K. L. Warfield J. G. Perkins D. L. Swenson E. M. Deal C. M. Bosio

2004-01-01

398

Diagnostic strategy for occult hepatitis B virus infection  

PubMed Central

In 2008, the European Association for the study of the liver (EASL) defined occult hepatitis B virus infection (OBI) as the “presence of hepatitis B virus (HBV) DNA in the liver (with detectable or undetectable HBV DNA in the serum) of individuals testing hepatitis B surface antigen (HBsAg) negative by currently available assays”. Several aspects of occult HBV infection are still poorly understood, including the definition itself and a standardized approach for laboratory-based detection, which is the purpose of this review. The clinical significance of OBI has not yet been established; however, in terms of public health, the clinical importance arises from the risk of HBV transmission. Consequently, it is important to detect high-risk groups for occult HBV infection to prevent transmission. The main issue is, perhaps, to identify the target population for screening OBI. Viremia is very low or undetectable in occult HBV infection, even when the most sensitive methods are used, and the detection of the viral DNA reservoir in hepatocytes would provide the best evaluation of occult HBV prevalence in a defined set of patients. However, this diagnostic approach is obviously unsuitable: blood detection of occult hepatitis B requires assays of the highest sensitivity and specificity with a lower limit of detection < 10 IU/mL for HBV DNA and < 0.1 ng/mL for HBsAg.

Ocana, Sara; Casas, Maria Luisa; Buhigas, Ingrid; Lledo, Jose Luis

2011-01-01

399

Pathogenesis of occult chronic hepatitis B virus infection  

PubMed Central

Occult hepatitis B infection (OBI) is characterized by hepatitis B virus (HBV) DNA in serum in the absence of hepatitis B surface antigen (HBsAg) presenting HBsAg-negative and anti-HBc positive serological patterns. Occult HBV status is associated in some cases with mutant viruses undetectable by HBsAg assays; but more frequently it is due to a strong suppression of viral replication and gene expression. OBI is an entity with world-wide diffusion. The failure to detect HBsAg, despite the persistence of the viral DNA, is due in most cases to the strong suppression of viral replication and gene expression that characterizes this “occult” HBV infection; although the mechanisms responsible for suppression of HBV are not well understood. The majority of OBI cases are secondary to overt HBV infection and represent a residual low viremia level suppressed by a strong immune response together with histological derangements which occurred during acute or chronic HBV infection. Much evidence suggests that it can favour the progression of liver fibrosis and the development of hepatocellular carcinoma.

de la Fuente, Rocio Aller; Gutierrez, Maria L; Garcia-Samaniego, Javier; Fernandez-Rodriguez, Conrado; Lledo, Jose Luis; Castellano, Gregorio

2011-01-01

400

Kinetics of Acute Hepatitis B Virus Infection in Humans  

PubMed Central

Using patient data from a unique single source outbreak of hepatitis B virus (HBV) infection, we have characterized the kinetics of acute HBV infection by monitoring viral turnover in the serum during the late incubation and clinical phases of the disease in humans. HBV replicates rapidly with minimally estimated doubling times ranging between 2.2 and 5.8 d (mean 3.7 ± 1.5 d). After a peak viral load in serum of nearly 1010 HBV DNA copies/ml is attained, clearance of HBV DNA follows a two or three phase decay pattern with an initial rapid decline characterized by mean half-life (t1/2) of 3.7 ± 1.2 d, similar to the t1/2 observed in the noncytolytic clearance of covalently closed circular DNA for other hepadnaviruses. The final phase of virion clearance occurs at a variable rate (t1/2 of 4.8 to 284 d) and may relate to the rate of loss of infected hepatocytes. Free virus has a mean t1/2 of at most 1.2 ± 0.6 d. We estimate a peak HBV production rate of at least 1013 virions/day and a maximum production rate of an infected hepatocyte of 200–1,000 virions/day, on average. At this peak rate of virion production we estimate that every possible single and most double mutations would be created each day.

Whalley, Simon A.; Murray, John M.; Brown, Dave; Webster, George J.M.; Emery, Vincent C.; Dusheiko, Geoffrey M.; Perelson, Alan S.

2001-01-01

401

Establishment of a Vero cell line persistently infected with African swine fever virus.  

PubMed Central

A Vero cell line persistently infected with African swine fever virus was established by infecting the cells in the presence of 10 mM NH4Cl (Vero-P cell line). The virus derived from the Vero-P cultures infected Vero cells, and virus titers were comparable to those obtained in Vero cells acutely infected with African swine fever virus. The structural proteins of the virus from Vero-P cells were similar to those of the virus produced in lytic infections. Virus production was low when the Vero-P cells were growing logarithmically and increased considerably in confluent cultures when lysis appeared in a fraction of the cell population. Images

Salas, J; Vinuela, E

1986-01-01

402

Frequent infection of neurons by SV40 virus in SIV-infected macaque monkeys with progressive multifocal leukoencephalopathy and meningoencephalitis.  

PubMed

Simian virus 40 (SV40), family Polyomaviridae, in immunocompromised macaques can cause fatal demyelinating central nervous system disease analogous to progressive multifocal leukoencephalopathy caused by John Cunningham (JC) virus in immunocompromised humans. Recently, we have demonstrated that JC virus can infect cerebellar granule cell neurons and cortical pyramidal neurons in immunosuppressed people. To examine whether SV40 neuronal infection occurs spontaneously in immunosuppressed macaques, we analyzed archival brain specimens from 20 simian immunodeficiency virus-infected rhesus with AIDS and 1 cynomolgus post-transplant selected with SV40 brain infection from archival records from 1991 to 2012. In addition to white matter SV40 distribution in classic demyelinating progressive multifocal leukoencephalopathy, some of the 21 monkeys exhibited meningeal, subpial neocortical, and periventricular virus. This distribution pattern corresponded to broader viral tropism with neuronal infection in 14 (66.7%) of 21 cases. In all 14 cases, identified neurons were positive for early SV40 transcript large T antigen, but only 4 of the 14 cases exhibited late viral transcript viral protein 1-positive neurons. SV40-infected neurons were detected in frontal, parietal, occipital, and temporal cortices, hippocampus, thalamus, and brain stem. These observations confirm that spontaneous SV40 neuronal infection occurs in immunosuppressed macaques, which parallels JC virus-neuronal infection in immunosuppressed patients. Neuronal infection may be an important aspect of both SV40 and JC virus neuropathogenesis in their respective hosts. PMID:24095925

Kaliyaperumal, Saravanan; Dang, Xin; Wuethrich, Christian; Knight, Heather L; Pearson, Christine; MacKey, John; Mansfield, Keith G; Koralnik, Igor J; Westmoreland, Susan V

2013-12-01

403

Remarkable sequence similarity between the dinoflagellate-infecting marine girus and the terrestrial pathogen African swine fever virus.  

PubMed

Heterocapsa circularisquama DNA virus (HcDNAV; previously designated as HcV) is a giant virus (girus) with a approximately 356-kbp double-stranded DNA (dsDNA) genome. HcDNAV lytically infects the bivalve-killing marine dinoflagellate H. circularisquama, and currently represents the sole DNA virus isolated from dinoflagellates, one of the most abundant protists in marine ecosystems. Its morphological features, genome type, and host range previously suggested that HcDNAV might be a member of the family Phycodnaviridae of Nucleo-Cytoplasmic Large DNA Viruses (NCLDVs), though no supporting sequence data was available. NCLDVs currently include two families found in aquatic environments (Phycodnaviridae, Mimiviridae), one mostly infecting terrestrial animals (Poxviridae), another isolated from fish, amphibians and insects (Iridoviridae), and the last one (Asfarviridae) exclusively represented by the animal pathogen African swine fever virus (ASFV), the agent of a fatal hemorrhagic disease in domestic swine. In this study, we determined the complete sequence of the type B DNA polymerase (PolB) gene of HcDNAV. The viral PolB was transcribed at least from 6 h post inoculation (hpi), suggesting its crucial function for viral replication. Most unexpectedly, the HcDNAV PolB sequence was found to be closely related to the PolB sequence of ASFV. In addition, the amino acid sequence of HcDNAV PolB showed a rare amino acid substitution within a motif containing highly conserved motif: YSDTDS was found in HcDNAV PolB instead of YGDTDS in most dsDNA viruses. Together with the previous observation of ASFV-like sequences in the Sorcerer II Global Ocean Sampling metagenomic datasets, our results further reinforce the ideas that the terrestrial ASFV has its evolutionary origin in marine environments. PMID:19860921

Ogata, Hiroyuki; Toyoda, Kensuke; Tomaru, Yuji; Nakayama, Natsuko; Shirai, Yoko; Claverie, Jean-Michel; Nagasaki, Keizo

2009-01-01

404

Differing Effects of Herpes Simplex Virus 1 and Pseudorabies Virus Infections on Centrosomal Function  

PubMed Central

Efficient intracellular transport of the capsid of alphaherpesviruses, such as herpes simplex virus 1 (HSV-1), is known to be dependent upon the microtubule (MT) network. Typically, the MT network radiates from an MT-organizing center (MTOC), which is, in most cases, the centrosome. During herpesvirus egress, it has been assumed that capsids travel first from the nucleus to the centrosome and then from the centrosome to the site of envelopment. Here we report that the centrosome is no longer a primary MTOC in HSV-1-infected cells, but it retains this function in cells infected by another alphaherpesvirus, pseudorabies virus (PrV). As a result, MTs formed at late times after infection with PrV grow from a major, centralized MTOC, while those formed after HSV-1 infection arise from dispersed locations in the cytoplasm, indicating the presence of alternative and minor MTOCs. Thus, loss of the principal MT nucleating center in cells following HSV-1 infection raises questions about the mechanism of HSV-1 capsid egress. It is possible that, rather than passing via the centrosome, capsids may travel directly to the site of envelopment after exiting the nucleus. We suggest that, in HSV-1-infected cells, the disruption of centrosomal functions triggers reorganization of the MT network to favor noncentrosomal MTs and promote efficient viral spread.

Labetoulle, Marc; Rixon, Frazer J.

2013-01-01

405

Cytokine expression during chronic versus occult hepatitis B virus infection in HIV co-infected individuals  

PubMed Central

Chronic hepatitis B virus infection is characterized by persistent detectable levels of hepatitis B surface antigen (HBsAg) and HBV DNA in the serum. In contrast, HBsAg is not detectable during occult HBV infection, despite the presence of HBV DNA. An altered host immune response could play a role in the development of occult HBV infection; however, potential differences in immune responses among chronic and occult HBV-infected patients have not been evaluated in vivo. In the current study, we evaluated serum levels of regulatory, apoptotic, and fibrotic/anti-fibrotic cytokines/markers as indicators of immune responses in 25 chronic and 12 occult HBV-infected patients. More than half of the patients in both chronic and occult HBV infection groups had IL-2, IL-4, IL-13, and IFN-? levels below detectable limits. In contrast, most patients had detectable levels of IL-8, IL-10, IP-10, sFas, sFasL, and TGF-?1. Of these, only sFas was significantly different between the two groups, with lower levels observed during occult compared to chronic HBV infection (p = 0.01). As a surrogate marker of apoptotic inhibition, decreased sFas during occult HBV infection suggests that apoptosis occurs at different rates in occult compared to chronic HBV infection and therefore, may contribute to persistence of occult HBV infection.

Martin, Christina M.; Welge, Jeffrey A.; Shire, Norah J.; Shata, Mohamed T.; Sherman, Kenneth E.; Blackard, Jason T.

2011-01-01

406

Peginterferon and ribavirin treatment for hepatitis C virus infection  

PubMed Central

Pegylated interferon ? (IFN?) in combination with ribavirin is currently recommended as a standard-of-care treatment for chronic hepatitis C virus (HCV) infection. This combination therapy has drastically improved the rate of sustained virological response, specifically in difficult-to-treat patients. Recently, individualized treatment, such as response-guided therapy, is being developed based on host-, HCV- and treatment-related factors. Furthermore, modified regimens with currently available medications, novel modified IFN? and ribavirin or combinations with specifically targeted antiviral therapy for HCV agents, are currently being investigated. The purpose of this review is to address some issues and epoch-making topics in the treatment of chronic HCV infection, and to discuss more optimal and highly individualized therapeutic strategies for HCV-infected patients.

Tsubota, Akihito; Fujise, Kiyotaka; Namiki, Yoshihisa; Tada, Norio

2011-01-01

407

Molecular evidence of simian virus 40 infections in children  

NASA Technical Reports Server (NTRS)

Recent studies have detected simian virus 40 (SV40) DNA in certain human tumors and normal tissues. The significance of human infections by SV40, which was first discovered as a contaminant of poliovirus vaccines used between 1955 and 1963, remains unknown. The occurrence of SV40 infections in unselected hospitalized children was evaluated. Polymerase chain reaction and DNA sequence analyses were done on archival tissue specimens from patients positive for SV40 neutralizing antibody. SV40 DNA was identified in samples from 4 of 20 children (1 Wilms' tumor, 3 transplanted kidney samples). Sequence variation among SV40 regulatory regions ruled out laboratory contamination of specimens. This study shows the presence of SV40 infections in pediatric patients born after 1982.

Butel, J. S.; Arrington, A. S.; Wong, C.; Lednicky, J. A.; Finegold, M. J.

1999-01-01

408

Follicular dendritic cells and human immunodeficiency virus infectivity  

NASA Astrophysics Data System (ADS)

LARGE amounts of human immunodeficiency virus (HIV) localize on follicular dendritic cells (FDC) in the follicles of secondary lymphoid tissues following viral infection1,2. During clinical latency, active viral infection occurs primarily at these sites3,4. As HIV on FDC is in the form of immune complexes5, some of which may be formed with neutralizing antibody, we investigated whether HIV on FDC is infectious. We report here that HIV on FDC is highly infectious. Furthermore, FDC can convert neutralized HIV into an infectious form even in the presence of a vast excess of neutralizing antibody. Thus FDC may provide a mechanism whereby HIV infection can continue in the presence of neutralizing antibody.

Heath, Sonya L.; Tew, J. Grant; Tew, John G.; Szakal, Andras K.; Burton, Gregory F.

1995-10-01

409

Experimental infections of wild birds with West Nile virus.  

PubMed

Avian models of West Nile virus (WNV) disease have become pivotal in the study of infection pathogenesis and transmission, despite the intrinsic constraints that represents this type of experimental research that needs to be conducted in biosecurity level 3 (BSL3) facilities. This review summarizes the main achievements of WNV experimental research carried out in wild birds, highlighting advantages and limitations of this model. Viral and host factors that determine the infection outcome are analyzed in detail, as well as recent discoveries about avian immunity, viral transmission, and persistence achieved through experimental research. Studies of laboratory infections in the natural host will help to understand variations in susceptibility and reservoir competence among bird species, as well as in the epidemiological patterns found in different affected areas. PMID:24531334

Pérez-Ramírez, Elisa; Llorente, Francisco; Jiménez-Clavero, Miguel Ángel

2014-02-01

410

Innate Immune Control of West Nile Virus Infection  

PubMed Central

West Nile virus (WNV), from the Flaviviridae family, is a re-emerging zoonotic pathogen of medical importance. In humans, WNV infection may cause life-threatening meningoencephalitis or long-term neurologic sequelae. WNV is transmitted by Culex spp mosquitoes and both the arthropod vector and the mammalian host are equipped with antiviral innate immune mechanisms sharing a common phylogeny. As far as the current evidence is able to demonstrate, mosquitoes primarily rely on RNA interference, Toll, Imd and JAK-STAT signaling pathways for limiting viral infection, while mammals are provided with these and other more complex antiviral mechanisms involving antiviral effectors, inflammatory mediators, and cellular responses triggered by highly specialized pathogen detection mechanisms that often resemble their invertebrate ancestry. This mini-review summarizes our current understanding of how the innate immune systems of the vector and the mammalian host react to WNV infection and shape its pathogenesis.

Arjona, Alvaro; Wang, Penghua; Montgomery, Ruth R.; Fikrig, Erol

2011-01-01

411

An overview of occult hepatitis B virus infection  

PubMed Central

Occult hepatitis B virus (HBV) infection (OBI), alternatively defined as occult hepatitis B (OHB), is a challenging clinical entity. It is recognized by two main characteristics: absence of HBsAg, and low viral replication. The previous two decades have witnessed a remarkable progress in our understanding of OBI and its clinical implications. Appropriate diagnostic techniques must be adopted. Sensitive HBV DNA amplification assay is the gold standard assay for detection of OBI. Viral as well as host factors are implicated in the pathogenesis of OBI. However, published data reporting the infectivity of OBI by transfusion are limited. Several aspects including OBI transmission, infectivity and its relation to the development of chronic liver diseases and hepatocellular carcinoma have to be resolved. The aim of the present review is to highlight recent data on OBI with a focus on its virological diagnosis and clinical outcome.

Said, Zeinab Nabil Ahmed

2011-01-01

412

Novel approaches towards conquering hepatitis B virus infection  

PubMed Central

Currently approved treatments for hepatitis B virus (HBV) infection include the immunomodulatory agent, IFN-?, and nucleos(t)ide analogues. Their efficacy is limited by their side effects, as well as the induction of viral mutations that render them less potent. It is thus necessary to develop drugs that target additional viral antigens. Chemicals and biomaterials by unique methods of preventing HBV replication are currently being developed, including novel nucleosides and newly synthesized compounds such as capsid