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1

Influenza A(H1N1)pdm09 virus infection in giant pandas, China.  

PubMed

We confirmed infection with influenza A(H1N1)pdm09 in giant pandas in China during 2009 by using virus isolation and serologic analysis methods. This finding extends the host range of influenza viruses and indicates a need for increased surveillance for and control of influenza viruses among giant pandas. PMID:24565026

Li, Desheng; Zhu, Ling; Cui, Hengmin; Ling, Shanshan; Fan, Shengtao; Yu, Zhijun; Zhou, Yuancheng; Wang, Tiecheng; Qian, Jun; Xia, Xianzhu; Xu, Zhiwen; Gao, Yuwei; Wang, Chengdong

2014-03-01

2

Influenza A(H1N1)pdm09 Virus Infection in Giant Pandas, China  

PubMed Central

We confirmed infection with influenza A(H1N1)pdm09 in giant pandas in China during 2009 by using virus isolation and serologic analysis methods. This finding extends the host range of influenza viruses and indicates a need for increased surveillance for and control of influenza viruses among giant pandas. PMID:24565026

Li, Desheng; Zhu, Ling; Cui, Hengmin; Ling, Shanshan; Fan, Shengtao; Yu, Zhijun; Zhou, Yuancheng; Wang, Tiecheng; Qian, Jun; Xia, Xianzhu; Xu, Zhiwen; Wang, Chengdong

2014-01-01

3

Epidermal multinucleated giant cells are not always a histopathologic clue to a herpes virus infection: multinucleated epithelial giant cells in the epidermis of lesional skin biopsies from patients with acantholytic dermatoses can histologically mimic a herpes virus infection  

PubMed Central

Background: Multinucleated giant cells in the epidermis can either be epithelial or histiocytic. Epithelial multinucleated giant cells are most often associated with herpes virus infections. Purpose: To review the histologic differential diagnosis of conditions with epithelial and histiocytic multinucleated giant cells—since multinucleated giant cells in the epidermis are not always pathognomonic of a cutaneous herpes virus infection—and to summarize dermatoses in which herpes virus infection has been observed to coexist. Methods: Two individuals with acantholytic dermatoses whose initial lesional skin biopsies showed multinucleated epithelial giant cells suggestive of a herpes virus infection are reported. Using the PubMed database, an extensive literature search was performed on multinucleated giant cell (and epidermis, epithelial, and histiocytic) and herpes virus infection. Relevant papers were reviewed to discover the skin conditions with either multinucleated giant cells in the epidermis or coincident cutaneous herpes virus infection. Results: Initial skin biopsies from patients with either pemphigus vulgaris or transient acantholytic dermatosis mimicked herpes virus infection; however, laboratory studies and repeat biopsies established the correct diagnosis of their acantholytic dermatosis. Hence, epidermal multinucleated giant cells are not always a histopathologic clue to a herpes virus infection. Indeed, epithelial multinucleated giant cells in the epidermis can be observed not only in the presence of infection (herpes virus), but also acantholytic dermatoses and tumors (trichoepithelioma and pleomorphic basal cell carcinoma). Histiocytic multinucleated giant cells in the epidermis can be observed in patients with either giant cell lichenoid dermatitis or lichen nitidus of the palms. Conclusions: Epithelial and histiocytic multinucleated giant cell can occur in the epidermis. Keratinocyte-derived multinucleated giant cells are most commonly associated with herpes virus infection; yet, they can also be observed in patients with skin tumors or acantholytic dermatoses. Cutaneous herpes simplex virus infection can coexist in association with other conditions such as acantholytic dermatoses, benign skin tumors, bullous disorders, hematologic malignancies, inflammatory dermatoses, and physical therapies. However, when a herpes virus infection is suspected based upon the discovery of epithelial multinucleated giant cells in the epidermis, but either the clinic presentation or lack of response to viral therapy or absence of confirmatory laboratory studies does not support the diagnosis of a viral infection, the possibility of a primary acantholytic dermatosis should be considered and additional lesional skin biopsies performed. Also, because hematoxylin and eosin staining is not the golden standard for confirmation of autoimmune bullous dermatoses, skin biopsies for direct immunofluorescence should be performed when a primary bullous dermatosis is suspected since the histopathology observed on hematoxylin and eosin stained sections can be misleading. PMID:25396080

Cohen, Philip R.; Paravar, Taraneh; Lee, Robert A.

2014-01-01

4

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. PMID:24969138

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

2014-01-01

5

Characterisation of three novel giant viruses reveals huge diversity among viruses infecting Prymnesiales (Haptophyta).  

PubMed

We have isolated three novel lytic dsDNA-viruses from Raunefjorden (Norway) that are putative members of the Mimiviridae family, namely Haptolina ericina virus RF02 (HeV RF02), Prymnesium kappa virus RF01 (PkV RF01), and Prymnesium kappa virus RF02 (PkV RF02). Each of the novel haptophyte viruses challenges the common conceptions of algal viruses with respect to host range, phylogenetic affiliation and size. PkV RF01 has a capsid of ~310 nm and is the largest algal virus particle ever reported while PkV RF01 and HeV RF02 were able to infect different species, even belonging to different genera. Moreover, PkV RF01 and HeV RF02 infected the same hosts, but phylogenetic analysis placed them in different groups. Our results reveal large variation among viruses infecting closely related microalgae, and challenge the common conception that algal viruses have narrow host range, and phylogeny reflecting their host affiliation. PMID:25546253

Johannessen, Torill Vik; Bratbak, Gunnar; Larsen, Aud; Ogata, Hiroyuki; Egge, Elianne S; Edvardsen, Bente; Eikrem, Wenche; Sandaa, Ruth-Anne

2015-02-01

6

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

7

Giant anal condylomatosis after allogeneic bone marrow transplantation: a rare complication of human papilloma virus infection.  

PubMed

Condyloma acuminata or genital warts are caused by human papilloma virus (HPV). Ongoing proliferation of HPV in patients with congenital or acquired immunodeficiency states leads to the development of rapidly progressive and sometimes locally invasive tumor with or without dysplasia. Aggressive treatment, diagnostic immuno-typing, and follow-up are necessary in patients with ongoing immunosuppression. We report a case of giant ano-genital condylomatosis due to HPV types 6 and 11 in a patient with chronic myeloid leukemia after allogeneic bone marrow transplantation. The tumor was successfully treated with surgical excision and local application of 5% imiquimod cream. PMID:17511821

Ganguly, N; Waller, S; Stasik, C J; Skikne, B S; Ganguly, S

2008-02-01

8

Hypoxia Induces Permeability and Giant Cell Responses of Andes Virus-Infected Pulmonary Endothelial Cells by Activating the mTOR-S6K Signaling Pathway  

PubMed Central

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.

2013-01-01

9

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. PMID:23919155

Wodarz, Dominik

2013-01-01

10

Giant cell encephalitis and microglial infection with mucosally transmitted simian-human immunodeficiency virus SHIVSF162P3N in rhesus macaques.  

PubMed

Neurocognitive disorders such as dementia and cognitive/motor impairments are among the most significant complications associated with human immunodeficiency virus (HIV) infection, especially in aging populations, yet the pathogenesis remains poorly understood. Activated macrophages and microglia in white matter along with the hallmark multinucleated giant cells are prominent features of HIV encephalitis (HIVE) and of several simian immunodeficiency virus (SIV) models. While infected microglia have been demonstrated in HIVE, this feature is not routinely seen in experimental infections in rhesus macaques using SIV or chimeric simian/HIV (SHIV) strains, limiting utility in HIV-1 pathogenesis and treatment studies. Here, 50 rhesus macaques were inoculated with the CCR5 (R5)-tropic SHIVSF162P3N virus by one of three routes: intravenously (n?=?9), intrarectally (n?=?17), or intravaginally (n?=?24). Forty-three monkeys became viremic, 26 developed AIDS, and 7 (7/26, 27 %) developed giant cell SIV encephalitis (SIVE). Rapid progressor phenotype was evident in five of seven (71 %) macaques with SIVE, and expansion to utilize the CXCR4 coreceptor (X4 coreceptor switch) was observed in four out of seven (57 %). SIVE lesions were present in gray and white matter in the cerebrum, cerebellum, thalamus, and brain stem of affected animals. Lesions were composed of virally infected CD68(+), CD163(+), and HLA-DR(+) macrophages accompanied by white matter damage, necrosis, and astroglial and microglial activation. Importantly, microglial infection was observed, which makes R5 SHIVSF162P3N infection of macaques an attractive animal model not only to study transmission and HIVE pathogenesis but also to conduct preclinical evaluation of therapeutic interventions aimed at eradicating HIV-1 from the central nervous system (CNS). PMID:24464410

Harbison, Carole; Zhuang, Ke; Gettie, Agegnehu; Blanchard, James; Knight, Heather; Didier, Peter; Cheng-Mayer, Cecilia; Westmoreland, Susan

2014-02-01

11

Viruses Infecting Reptiles  

PubMed Central

A large number of viruses have been described in many different reptiles. These viruses include arboviruses that primarily infect mammals or birds as well as viruses that are specific for reptiles. Interest in arboviruses infecting reptiles has mainly focused on the role reptiles may play in the epidemiology of these viruses, especially over winter. Interest in reptile specific viruses has concentrated on both their importance for reptile medicine as well as virus taxonomy and evolution. The impact of many viral infections on reptile health is not known. Koch’s postulates have only been fulfilled for a limited number of reptilian viruses. As diagnostic testing becomes more sensitive, multiple infections with various viruses and other infectious agents are also being detected. In most cases the interactions between these different agents are not known. This review provides an update on viruses described in reptiles, the animal species in which they have been detected, and what is known about their taxonomic positions. PMID:22163336

Marschang, Rachel E.

2011-01-01

12

Parainfluenza virus infections  

PubMed Central

Parainfluenza viruses types 1, 2 and 3 were found in 2·5%, 0·8% and 1·6% respectively of patients examined in the MRC/PHLS general practice survey and in 2·2%, 0·7% and 2·7% of those in the hospital survey. Type 3 infections were found earlier in life than type 1, while type 2 infections tended to be detected in older children. These viruses were found most frequently in croup and laryngitis but were also common causes of coryza and lower respiratory infections, especially in general practice. The epidemiology and diagnosis of parainfluenza virus infections are discussed briefly. PMID:4377299

Clarke, Suzanne K. R.

1973-01-01

13

Respiratory syncytial virus infections  

PubMed Central

RS virus was isolated from 10·5% of the specimens examined in the MRC/PHLS hospital survey and from 0·9% of those in the general practice survey. The highest isolation rates were in infants with lower respiratory tract infections. Dyspnoea, wheezing and cough were the predominant clinical features. The differences in the rates between hospital and general practice and newer methods of diagnosis of RS virus infection are discussed. PMID:4806397

Gardner, P. S.

1973-01-01

14

Preliminary characterisation of repeat families in the genome of EhV86, a giant algal virus that infects the marine microalga Emiliania huxleyi  

Microsoft Academic Search

Summary.  EhV-86 is a large double stranded DNA virus with a 407,339 base pair circular genome that infects the globally important microalga\\u000a Emiliania huxleyi. It belongs to a new genus of viruses termed the Coccolithoviridae within the algal virus family Phycodnaviridae. By plotting the EhV-86 genome against itself in a dot-plot analysis we revealed three families of distinctly different repeat\\u000a sequences

M. J. Allen; D. C. Schroeder; W. H. Wilson

2006-01-01

15

Molluscum contagiosum virus infection.  

PubMed

Molluscum contagiosum virus is an important human skin pathogen: it can cause disfigurement and suffering in children, in adults it is less common and often sexually transmitted. Extensive and persistent skin infection with the virus can indicate underlying immunodeficiency. Traditional ablative therapies have not been compared directly with newer immune-modulating and specific antiviral therapies. Advances in research raise the prospect of new approaches to treatment informed by the biology of the virus; in human skin, the infection is localised in the epidermal layers, where it induces a typical, complex hyperproliferative lesion with an abundance of virus particles but a conspicuous absence of immune effectors. Functional studies of the viral genome have revealed effects on cellular pathways involved in the cell cycle, innate immunity, inflammation, and cell death. Extensive lesions caused by molluscum contagiosum can occur in patients with DOCK8 deficiency-a genetic disorder affecting migration of dendritic and specialised T cells in skin. Sudden disappearance of lesions is the consequence of a vigorous immune response in healthy people. Further study of the unique features of infection with molluscum contagiosum virus could give fundamental insight into the nature of skin immunity. PMID:23972567

Chen, Xiaoying; Anstey, Alex V; Bugert, Joachim J

2013-10-01

16

Hepatitis E Virus Infection  

PubMed Central

SUMMARY 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

Dalton, Harry R.; Abravanel, Florence; Izopet, Jacques

2014-01-01

17

Respiratory syncytial virus infection in mice.  

PubMed Central

The A2 strain of human respiratory syncytial virus replicated in the nose and lung of BALB/c mice, with virus growing to higher titers in older animals than in younger animals. Virus was recovered from the nose between days 2 and 7 with peak titers on days 3 and 4, and from the lungs between days 2 and 9, with peak titers on days 4 through 6. Serum antibody developed 2 weeks after infection. Viral antigen was demonstrated in the alveolar cells of the lung by immunofluorescence. Histopathological changes included infiltration by mononuclear cells of the peribronchiolar and perivascular tissue, some interstitial thickening, and formation of multinucleated giant cells. Virus could not be recovered from the respiratory tract of mice inoculated with bovine strains of respiratory syncytial virus. Growth of the A2 strain of human respiratory syncytial virus in different cell lines affected its infectivity for mice. Infection of BALB/c mice with respiratory syncytial virus provides a highly reproducible model for the study of the pathogenesis of and mechanisms of immunity to this virus. Images PMID:6693171

Taylor, G; Stott, E J; Hughes, M; Collins, A P

1984-01-01

18

Giant viruses in the oceans : the 4th Algal Virus Workshop  

E-print Network

Giant viruses in the oceans : the 4th Algal Virus Workshop Jean-Michel Claverie Structural: +33 4 91 16 45 49 Jean-Michel.Claverie@igs.cnrs-mrs.fr 1 #12;Abstract Giant double-stranded DNA optimally fitted to the smallest possible ­filterable- package. Such giant viruses are now discovered

Boyer, Edmond

19

West Nile Virus Infection and Pregnancy  

MedlinePLUS

... online at: http://www.mothertobaby.org/. West Nile Virus Infection and Pregnancy In every pregnancy, a woman ... your health care professional. What is West Nile Virus (WNV)? WNV is a virus that can infect ...

20

Acute hepatitis C virus infection.  

PubMed

Around 25% of people infected with hepatitis C virus (HCV) are able to clear the infection spontaneously, while the majority become chronically infected, with a subsequent risk for the individual patient of progressive inflammatory liver disease, cirrhosis, hepatocellular carcinoma and liver-related death (Figure 1). Much is known about the epidemiology, pathogenesis, diagnosis and management of chronic HCV infection. In comparison, knowledge about acute HCV infection is patchy. In this article, we will highlight concerns relating to acute HCV infection and suggest that public health bodies responsible for managing the HCV epidemic should redirect at least some of their resources to dealing with these issues. PMID:18761963

Irving, W L; Salmon, D; Boucher, C; Hoepelman, I M

2008-05-22

21

Respiratory Syncytial Virus Infections  

MedlinePLUS

Respiratory syncytial virus (RSV) causes mild, cold-like symptoms in adults and older healthy children. It can cause serious problems in ... tests can tell if your child has the virus. There is no specific treatment. You should give ...

22

Human Papilloma Virus Infections  

PubMed Central

Genital warts are believed to be caused by human papilloma viruses and to be sexually transmitted. The viruses are classified by DNA types, which appear to cause different types of disease. The choice of treatment, and usually its success rate, vary according to the type of disease and its location. PMID:21248973

Wright, V. Cecil

1989-01-01

23

Preventing respiratory syncytial virus infections.  

PubMed

Respiratory syncytial virus infection is the leading cause of lower respiratory tract infections in young children. Palivizumab, a respiratory syncytial virus-specific monoclonal antibody, reduces the hospitalization rate of high-risk children but it is very costly. This statement replaces three previous position statements from the Canadian Paediatric Society about this topic, and was updated primarily to discuss recent changes in the American Academy of Pediatrics guidelines in the Canadian context. It reviews the published literature and provides recommendations regarding palivizumab use in high-risk children. PMID:23024588

Robinson, Jl

2011-10-01

24

MEDLINEPlus: Monkeypox Virus Infections  

NSDL National Science Digital Library

Readers can keep up with the latest developments in the Monkeypox outbreak with this straightforward Web site from MEDLINEplus. The site features the latest Monkeypox news as well as links to authoritative sites for background information about the virus. Readers will also find information on prevention and screening, updated statistics on the outbreak from the Center for Disease Control and Prevention, and more. The site also includes a downloadable electron micrograph of the Monkeypox virus.

25

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. PMID:23737745

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

2013-01-01

26

Neonatal herpes simplex virus infection  

PubMed Central

Neonatal herpes, seen roughly in 1 of 3,000 live births in the United States, is the most serious manifestation of herpes simplex virus (HSV) infection in the perinatal period. Although acyclovir therapy decreases infant mortality associated with perinatal HSV transmission, development of permanent neurologic disabilities is not uncommon. Mother-to-neonate HSV transmission is most efficient when maternal genital tract HSV infection is acquired proximate to the time of delivery, signifying that neonatal herpes prevention strategies need to focus on decreasing the incidence of maternal infection during pregnancy and more precisely identifying infants most likely to benefit from prophylactic antiviral therapy. PMID:23090462

Cherpes, Thomas L.; Matthews, Dean B.; Maryak, Samantha A.

2012-01-01

27

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 ...

28

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. PMID:24886672

2014-01-01

29

Respiratory Syncytial Virus Infection (RSV): Infection and Incidence  

MedlinePLUS

... Search The CDC Cancel Submit Search The CDC Respiratory Syncytial Virus Infection (RSV) Note: Javascript is disabled ... References & Resources Infographic Related Links Related Links Unexplained Respiratory Disease Outbreaks Red Book® Online Infection and Incidence ...

30

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...

31

Amoebae as Genitors and Reservoirs of Giant Viruses  

Microsoft Academic Search

Amoebae are unicellular phagocytes that feed on microorganisms in their environment. Some amoebae have the largest genome size currently known on earth. They phagocytose any inert particle larger than 0.5 ?m. Phagocytic amoebae can harbor different bacteria, fungi and giant viruses within the same cell. There is evidence of lateral gene transfer between the amoeba and its microbiological hosts. There

Didier Raoult; Mickael Boyer

2010-01-01

32

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

33

Models of dengue virus infection  

PubMed Central

The need for models of dengue disease has reached a pinnacle as the transmission of this mosquito-borne virus has increased dramatically. Little is known about the mechanisms that lead to dengue fever and its more severe form, dengue hemorrhagic fever; this is owing to the fact that only humans show signs of disease. In the past 5 years, research has better identified the initial target cells of infection, and this has led to the development of models of infection in primary human cell cultures. Mouse–human chimeras, containing these target cells, have also led to progress in developing animal models. These advances should soon end the stalemate in testing antivirals and vaccine preparations that had necessarily been done in incomplete or irrelevant models. PMID:18087566

Bente, Dennis A.; Rico-Hesse, Rebeca

2007-01-01

34

Acute transverse myelitis following dengue virus infection  

Microsoft Academic Search

The spinal cord is infrequently affected following dengue virus infection. We report a case of transverse myelitis that developed 2 weeks after acute dengue infection and review the literature to elucidate the pathogenesis of spinal cord involvement in dengue infection. We postulate that temporal factors may play a role in the different clinical manifestations, i.e. that acute parainfectious dengue infection

Raymond C. S. Seet; Erle C. H. Lim; Einar P. V. Wilder-Smith

2006-01-01

35

Influenza A Virus Infections in Land  

E-print Network

Influenza A Virus Infections in Land Birds, People's Republic of China A. Townsend Peterson, Sarah­PCR testing of 939 Asian land birds of 153 species. Influenza A infection was found, particularly among influenza virus ecology has long regarded water- birds as a primary reservoir. Although the benchmark study

Clayton, Dale H.

36

The greasy response to virus infections.  

PubMed

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. PMID:23601099

Tanner, Lukas Bahati; Lee, Benhur

2013-04-17

37

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. PMID:23601099

Tanner, Lukas Bahati; Lee, Benhur

2013-01-01

38

Systems analysis of West Nile virus infection.  

PubMed

Emerging and re-emerging mosquito-borne viruses continue to pose a significant threat to human health throughout the world. Over the past decade, West Nile virus (WNV), Dengue virus (DENV), and Chikungunya virus (CHIKV), have caused annual epidemics of virus-induced encephalitis, hemorrhagic fever\\shock syndromes, and arthritis, respectively. Currently, no specific antiviral therapies or vaccines exist for use in humans to combat or prevent these viral infections. Thus, there is a pressing need to define the virus-host interactions that govern immunity and infection outcome. Recent technological breakthroughs in 'omics' resources and high-throughput based assays are beginning to accelerate antiviral drug discovery and improve on current strategies for vaccine design. In this review, we highlight studies with WNV and discuss how traditional and systems biological approaches are being used to rapidly identify novel host targets for therapeutic intervention and develop a deeper conceptual understanding of the host response to virus infection. PMID:24851811

Suthar, Mehul S; Pulendran, Bali

2014-06-01

39

Lipid metabolism in experimental virus infections  

Microsoft Academic Search

A model of herpetic infection, namely keratoconjunctivitis (HKC) was created in chinchilla rabbits weighing 2-2.5 kg, with the aid of type 1 herpes simplex virus (HSV1, Koptev strain), with an infecting dose (ID) of 100 LDs0 [5]. A model of influenzal infection (II) was created in noninbred albino mice (weighing 15-20 g), using influenza virus (IV, strain A\\/Aichi\\/2\\/68 [H3N2]), with

T. V. Amvros'eva; V. I. Voltyakov; O. T. Andreeva; E. V. Serebryakova; G. V. Vladyko; M. P. Samarina

1992-01-01

40

Ebola Virus Infection: What Should Be Known?  

PubMed Central

Ebola virus infection is the present global consideration. This deadly virus can result in a deadly acute febrile hemorrhagic illness. The patient can have several clinical manifestations. As a new emerging infection, the knowledge on this infection is extremely limited. The interesting issues to be discussed include a) the atypical clinical presentation, b) new diagnostic tool, c) new treatment, and d) disease prevention. Those topics will be discussed in this special review. PMID:25535601

Wiwanitkit, Viroj

2014-01-01

41

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

42

RNA Viruses Infecting Pest Insects  

Technology Transfer Automated Retrieval System (TEKTRAN)

RNA viruses are viruses whose genetic material is ribonucleic acid (RNA). RNA viruses may be double or single-stranded based on the type of RNA they contain. Single-stranded RNA viruses can be further grouped into negative sense or positive-sense viruses according to the polarity of their RNA. Fur...

43

Genetic Influences on Dengue Virus Infections  

Microsoft Academic Search

Dengue virus infections are an important cause of morbidity and mortality in the tropics, with 100 million people infected annually and an estimated 2.5 billion people at risk. Human infections can be asymptomatic or can manifest as the self-limited febrile dengue fever, or the more severe and life- threatening dengue haemorrhagic fever (DHF). There are several possible reasons why some

J. F. P. Wagenaar; A. T. A. Mairuhu; E. C. M. van Gorp

2004-01-01

44

Occult hepatitis B virus infection  

PubMed Central

Occult hepatitis B virus (HBV) infection (OBI) refers to the presence of HBV DNA in the absence of detectable hepatitis B surface antigen. Since OBI was first described in the late 1970s, there has been increasing interest in this topic. The prevalence of OBI varies according to the different endemicity of HBV infection, cohort characteristics, and sensitivity and specificity of the methods used for detection. Although the exact mechanism of OBI has not been proved, intra-hepatic persistence of viral covalently closed circular DNA under the host’s strong immune suppression of HBV replication and gene expression seems to be a cause. OBI has important clinical significance in several conditions. First, OBI can be transmitted through transfusion, organ transplantation including orthotopic liver transplantation, or hemodialysis. Donor screening before blood transfusion, prophylaxis for high-risk organ transplantation recipients, and dialysis-specific infection-control programs should be considered to reduce the risk of transmission. Second, OBI may reactivate and cause acute hepatitis in immunocompromised patients or those receiving chemotherapy. Close HBV DNA monitoring and timely antiviral treatment can prevent HBV reactivation and consequent clinical deterioration. Third, OBI may contribute to the progression of hepatic fibrosis in patients with chronic liver disease including hepatitis C. Finally, OBI seems to be a risk factor for hepatocellular carcinoma by its direct proto-oncogenic effect and by indirectly causing persistent hepatic inflammation and fibrosis. However, this needs further investigation. We review published reports in the literature to gain an overview of the status of OBI and emphasize the clinical importance of OBI. PMID:25544873

Kwak, Min-Sun; Kim, Yoon Jun

2014-01-01

45

Occult hepatitis B virus infection.  

PubMed

Occult hepatitis B virus (HBV) infection (OBI) refers to the presence of HBV DNA in the absence of detectable hepatitis B surface antigen. Since OBI was first described in the late 1970s, there has been increasing interest in this topic. The prevalence of OBI varies according to the different endemicity of HBV infection, cohort characteristics, and sensitivity and specificity of the methods used for detection. Although the exact mechanism of OBI has not been proved, intra-hepatic persistence of viral covalently closed circular DNA under the host's strong immune suppression of HBV replication and gene expression seems to be a cause. OBI has important clinical significance in several conditions. First, OBI can be transmitted through transfusion, organ transplantation including orthotopic liver transplantation, or hemodialysis. Donor screening before blood transfusion, prophylaxis for high-risk organ transplantation recipients, and dialysis-specific infection-control programs should be considered to reduce the risk of transmission. Second, OBI may reactivate and cause acute hepatitis in immunocompromised patients or those receiving chemotherapy. Close HBV DNA monitoring and timely antiviral treatment can prevent HBV reactivation and consequent clinical deterioration. Third, OBI may contribute to the progression of hepatic fibrosis in patients with chronic liver disease including hepatitis C. Finally, OBI seems to be a risk factor for hepatocellular carcinoma by its direct proto-oncogenic effect and by indirectly causing persistent hepatic inflammation and fibrosis. However, this needs further investigation. We review published reports in the literature to gain an overview of the status of OBI and emphasize the clinical importance of OBI. PMID:25544873

Kwak, Min-Sun; Kim, Yoon Jun

2014-12-27

46

Ebola virus infection modeling and identifiability problems  

PubMed Central

The recent outbreaks of Ebola virus (EBOV) infections have underlined the impact of the virus as a major threat for human health. Due to the high biosafety classification of EBOV (level 4), basic research is very limited. Therefore, the development of new avenues of thinking to advance quantitative comprehension of the virus and its interaction with the host cells is urgently needed to tackle this lethal disease. Mathematical modeling of the EBOV dynamics can be instrumental to interpret Ebola infection kinetics on quantitative grounds. To the best of our knowledge, a mathematical modeling approach to unravel the interaction between EBOV and the host cells is still missing. In this paper, a mathematical model based on differential equations is used to represent the basic interactions between EBOV and wild-type Vero cells in vitro. Parameter sets that represent infectivity of pathogens are estimated for EBOV infection and compared with influenza virus infection kinetics. The average infecting time of wild-type Vero cells by EBOV is slower than in influenza infection. Simulation results suggest that the slow infecting time of EBOV could be compensated by its efficient replication. This study reveals several identifiability problems and what kind of experiments are necessary to advance the quantification of EBOV infection. A first mathematical approach of EBOV dynamics and the estimation of standard parameters in viral infections kinetics is the key contribution of this work, paving the way for future modeling works on EBOV infection.

Nguyen, Van Kinh; Binder, Sebastian C.; Boianelli, Alessandro; Meyer-Hermann, Michael; Hernandez-Vargas, Esteban A.

2015-01-01

47

Dengue Virus Infection Perturbs Lipid Homeostasis in Infected Mosquito Cells  

SciTech Connect

Dengue virus causes {approx}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 M.; Riley, Catherine; Isaac, Georgis; Hopf- Jannasch, Amber; Moore, Ronald J.; Weitz, Karl K.; Pasa-Tolic, Ljiljana; Metz, Thomas O.; Adamec, Jiri; Kuhn, Richard J.

2012-03-22

48

Human immunodeficiency virus infection and pneumothorax  

PubMed Central

Pneumothorax is a serious and relatively frequent complication of human immunodeficiency virus (HIV) infection that may associate with increased morbidity and mortality and may prove difficult to manage, especially in patients with acquired immunodeficiency syndrome (AIDS). PMID:25337392

Terzi, Eirini; Zarogoulidis, Konstantinos; Kougioumtzi, Ioanna; Dryllis, Georgios; Kioumis, Ioannis; Pitsiou, Georgia; Machairiotis, Nikolaos; Katsikogiannis, Nikolaos; Tsiouda, Theodora; Madesis, Athanasios; Karaiskos, Theodoros

2014-01-01

49

Neurological manifestations of dengue virus infection  

Microsoft Academic Search

AimPaucity of studies on neurological manifestations in dengue virus infection prompted this study. We aim to correlate clinical, radiological and neurophysiological changes in dengue patients with neurological manifestations.

U. K. Misra; J. Kalita; U. K. Syam; T. N. Dhole

2006-01-01

50

Lipid interactions during virus entry and infection  

PubMed Central

Summary For entry and infection viruses have developed numerous strategies to subjugate indispensable cellular factors and functions. Host cell lipids and cellular lipid synthesis machinery are no exception. Not only do viruses exploit existing lipid signalling and modifications for virus entry and trafficking, they also reprogram lipid synthesis, metabolism, and compartmentalization for assembly and egress. Here we review these various concepts and highlight recent progress in understanding viral interactions with host cell lipids during entry and assembly. PMID:25131438

Mazzon, Michela; Mercer, Jason

2014-01-01

51

Virus infection and human cancer: an overview.  

PubMed

It is now estimated that approximately 10 % of worldwide cancers are attributable to viral infection, with the vast majority (>85 %) occurring in the developing world. Oncogenic viruses include various classes of DNA and RNA viruses and induce cancer by a variety of mechanisms. A unifying theme is that cancer develops in a minority of infected individuals and only after chronic infection of many years duration. The viruses associated with the greatest number of cancer cases are the human papillomaviruses (HPVs), which cause cervical cancer and several other epithelial malignancies, and the hepatitis viruses HBV and HCV, which are responsible for the majority of hepatocellular cancer. Other oncoviruses include Epstein-Barr virus (EBV), Kaposi's sarcoma-associated herpes virus (KSHV), human T-cell leukemia virus (HTLV-I), and Merkel cell polyomavirus (MCPyV). Identification of the infectious cause has led to several interventions that may reduce the risk of developing these tumors. These include preventive vaccines against HBV and HPV, HPV-based testing for cervical cancer screening, anti-virals for the treatment of chronic HBV and HCV infection, and screening the blood supply for the presence of HBV and HCV. Successful efforts to identify additional oncogenic viruses in human cancer may lead to further insight into etiology and pathogenesis as well as to new approaches for therapeutic and prophylactic intervention. PMID:24008290

Schiller, John T; Lowy, Douglas R

2014-01-01

52

DIESEL EXHAUST ENHANCES INFLUENZA VIRUS INFECTIONS IN RESPIRATORY EPITHELIAL CELLS  

EPA Science Inventory

Several factors, such as age and nutritional status can affect the susceptibility to influenza infections. Moreover, exposure to air pollutants, such as diesel exhaust (DE), has been shown to affect respiratory virus infections in rodent models. Influenza virus primarily infects ...

53

Chronic Hepatitis E Virus Infection and Treatment  

PubMed Central

It is now well accepted that hepatitis E virus (HEV) infection can induce chronic hepatitis and cirrhosis in immunosuppressed patients. Chronic genotype-3 HEV infections were first reported in patients with a solid-organ transplant. Thereafter, cases of chronic HEV infection have been reported in patients with hematological disease and in those who are human immunodeficiency virus (HIV)-positive. HEV-associated extra-hepatic manifestations, including neurological symptoms, kidney injuries, and hematological disorders, have been also reported. In transplant patients, reducing the dosage of immunosuppressive drugs allows the virus to be cleared in some patients. In the remaining patients, as well as hematological patients and patients who are HIV-positive, anti-viral therapies, such as pegylated interferon and ribavirin, have been found to be efficient in eradicating HEV infection. This review summarizes our current knowledge of chronic HEV infection, its treatment, and the extra-hepatic manifestations induced by HEV.

Kamar, Nassim; Izopet, Jacques; Dalton, Harry R.

2013-01-01

54

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

55

Respiratory syncytial virus infection in cattle  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bovine respiratory syncytial virus (bRSV) is a cause of respiratory disease in cattle world-wide. It has an integral role in enzootic pneumonia in young dairy calves and summer pneumonia in nursing beef calves. Furthermore, bRSV infection can predispose calves to secondary bacterial infection by org...

56

THE INFECTION OF CHIMPANZEES WITH ECHO VIRUSES  

PubMed Central

The oral and parenteral infections of chimpanzees receiving echo Types 6 and 4 viruses successively are described. The two infections, spaced 2½ months apart, and given by the same route in each animal, failed to induce overt disease. The inapparent infections were demonstrated by virus excretion in the throat and the stools and the development of neutralizing antibodies. Complement-fixing antibodies also appeared after Type 6 infection, but fell more rapidly than the neutralizing antibodies. After oral infection, echo-6 virus was found for equal periods in both the throat and feces, but echo-4 persisted in the throat for much longer periods than in the lower bowel. Almost no virus carriage occurred after parenteral inoculation. No true viremia was exhibited in any of the animals. One of the chimpanzees had neutralizing antibodies against Type 6 virus in its pre-inoculation serum. It responded extraordinarily to the Type 6 exposure, developing antibody levels of 1:50,000 to echo-6, of 1:1024 against the echo-6' variant, and of 1:64 against the echo 6'' variant. Although Type 4 antibodies developed after the exposure, they proved difficult to measure by ordinary methods. However, they could be satisfactorily assayed by the plaque reduction method. Three other chimpanzees fed echo-2, echo-3, and an untypable echo virus, respectively, yielded results confirming those established with Types 4 and 6. PMID:13475623

Itoh, Heihachi; Melnick, Joseph L.

1957-01-01

57

Treatment of Ebola Virus Infection with Antibodies from Reconvalescent Donors  

PubMed Central

Clinical evidence suggests that antibodies from reconvalescent donors (persons who have recovered from infection) may be effective in the treatment of Ebola virus infection. Administration of this treatment to Ebola virus–infected patients while preventing the transmission of other pathogenic viruses may be best accomplished by use of virus-inactivated reconvalescent plasma. PMID:25695274

2015-01-01

58

Treatment of ebola virus infection with antibodies from reconvalescent donors.  

PubMed

Clinical evidence suggests that antibodies from reconvalescent donors (persons who have recovered from infection) may be effective in the treatment of Ebola virus infection. Administration of this treatment to Ebola virus-infected patients while preventing the transmission of other pathogenic viruses may be best accomplished by use of virus-inactivated reconvalescent plasma. PMID:25695274

Kreil, Thomas R

2015-03-01

59

Evolution of double-stranded DNA viruses of eukaryotes: from bacteriophages to transposons to giant viruses.  

PubMed

Diverse eukaryotes including animals and protists are hosts to a broad variety of viruses with double-stranded (ds) DNA genomes, from the largest known viruses, such as pandoraviruses and mimiviruses, to tiny polyomaviruses. Recent comparative genomic analyses have revealed many evolutionary connections between dsDNA viruses of eukaryotes, bacteriophages, transposable elements, and linear DNA plasmids. These findings provide an evolutionary scenario that derives several major groups of eukaryotic dsDNA viruses, including the proposed order "Megavirales," adenoviruses, and virophages from a group of large virus-like transposons known as Polintons (Mavericks). The Polintons have been recently shown to encode two capsid proteins, suggesting that these elements lead a dual lifestyle with both a transposon and a viral phase and should perhaps more appropriately be named polintoviruses. Here, we describe the recently identified evolutionary relationships between bacteriophages of the family Tectiviridae, polintoviruses, adenoviruses, virophages, large and giant DNA viruses of eukaryotes of the proposed order "Megavirales," and linear mitochondrial and cytoplasmic plasmids. We outline an evolutionary scenario under which the polintoviruses were the first group of eukaryotic dsDNA viruses that evolved from bacteriophages and became the ancestors of most large DNA viruses of eukaryotes and a variety of other selfish elements. Distinct lines of origin are detectable only for herpesviruses (from a different bacteriophage root) and polyoma/papillomaviruses (from single-stranded DNA viruses and ultimately from plasmids). Phylogenomic analysis of giant viruses provides compelling evidence of their independent origins from smaller members of the putative order "Megavirales," refuting the speculations on the evolution of these viruses from an extinct fourth domain of cellular life. PMID:25727355

Koonin, Eugene V; Krupovic, Mart; Yutin, Natalya

2015-04-01

60

Evolution of double-stranded DNA viruses of eukaryotes: from bacteriophages to transposons to giant viruses  

PubMed Central

Diverse eukaryotes including animals and protists are hosts to a broad variety of viruses with double-stranded (ds) DNA genomes, from the largest known viruses, such as pandoraviruses and mimiviruses, to tiny polyomaviruses. Recent comparative genomic analyses have revealed many evolutionary connections between dsDNA viruses of eukaryotes, bacteriophages, transposable elements, and linear DNA plasmids. These findings provide an evolutionary scenario that derives several major groups of eukaryotic dsDNA viruses, including the proposed order “Megavirales,” adenoviruses, and virophages from a group of large virus-like transposons known as Polintons (Mavericks). The Polintons have been recently shown to encode two capsid proteins, suggesting that these elements lead a dual lifestyle with both a transposon and a viral phase and should perhaps more appropriately be named polintoviruses. Here, we describe the recently identified evolutionary relationships between bacteriophages of the family Tectiviridae, polintoviruses, adenoviruses, virophages, large and giant DNA viruses of eukaryotes of the proposed order “Megavirales,” and linear mitochondrial and cytoplasmic plasmids. We outline an evolutionary scenario under which the polintoviruses were the first group of eukaryotic dsDNA viruses that evolved from bacteriophages and became the ancestors of most large DNA viruses of eukaryotes and a variety of other selfish elements. Distinct lines of origin are detectable only for herpesviruses (from a different bacteriophage root) and polyoma/papillomaviruses (from single-stranded DNA viruses and ultimately from plasmids). Phylogenomic analysis of giant viruses provides compelling evidence of their independent origins from smaller members of the putative order “Megavirales,” refuting the speculations on the evolution of these viruses from an extinct fourth domain of cellular life. PMID:25727355

Koonin, Eugene V; Krupovic, Mart; Yutin, Natalya

2015-01-01

61

Nipah virus infection, an emerging paramyxoviral zoonosis  

Microsoft Academic Search

.   The Nipah virus outbreak represented one of several bat-derived paramyxoviruses that has emerged during the last decade to\\u000a cause severe human and animal disease. The pathogenesis of Nipah infection is associated with its ability to infect blood\\u000a vessels and extravascular parenchyma in many organs, particularly in the central nervous system. The clinical manifestations\\u000a of acute Nipah infection range from

K. T. Wong; W. J. Shieh; S. R. Zaki; C. T. Tan

2002-01-01

62

Tentative Characterization of New Environmental Giant Viruses by MALDI-TOF Mass Spectrometry  

Microsoft Academic Search

Objective: Metagenomic studies have revealed that Acanthamoeba polyphaga Mimivirus relatives are common in the environment; however, only three Acanthamoeba-growing giant viruses have been isolated from hundreds of environmental samples. We attempted herein to isolate new Acanthamoeba-growing giant viruses from environmental samples. Methods: We inoculated 105 environmental samples by our usual procedure but with the addition of selected antibiotics to inhibit

Bernard La Scola; Angélique Campocasso; Rolande N’Dong; Ghislain Fournous; Lina Barrassi; Christophe Flaudrops; Didier Raoult

2010-01-01

63

Diagnosing and treating hepatitis C virus infection.  

PubMed

Hepatitis C virus (HCV) infection is the leading cause of cirrhosis and liver transplantation in the United States. It is difficult to assess the prevalence of HCV infection; the asymptomatic nature of acute infection and early chronic infection leaves many infected individuals undiagnosed. Exposure to infected blood is the primary means for HCV transmission, with intravenous drug use the most common source. Genotype 1 HCV infection accounts for approximately 75% of cases. Because of the asymptomatic and slow course of HCV infection, many physicians and healthcare advocates support routine testing at the primary care level, especially in patients 40 to 65 years of age. Approximately 80% of individuals infected with HCV fail to clear the virus, although this varies considerably based on sex, age at infection, immune status, route of infection, race, alcohol use, and presence of steatosis. Long-term outcomes of chronic HCV infection are cirrhosis, end-stage liver disease, and hepatocellular carcinoma. The current standard of care for patients with chronic HCV infection is combination therapy with subcutaneous injections of peginterferon plus oral ribavirin for 48 weeks. A sustained virologic response (SVR) is also considered a virologic "cure." There is a trend toward response-guided therapy, in which treatment duration is shortened or lengthened based on viral genotype, patient characteristics, and viral kinetics. The efficacy and tolerability of peginterferon therapy, however, is limited. Approximately 45% of patients infected with HCV genotype 1 achieve an SVR, whereas 65% of those infected with gentoype 2 or 3 do so. Moreover, retreatment or switching to other interferons provides little benefit. Several new therapies for HCV infection are in development. Protease inhibitors are expected to become the new standard of care for nonresponders, with the potential to become a first-line treatment for chronic HCV infection. PMID:21767067

Schiff, Eugene R

2011-03-01

64

SFTS Virus Infection in Nonhuman Primates.  

PubMed

SFTS virus (SFTSV) is a highly pathogenic bunyavirus that causes severe fever with thrombocytopenia syndrome (SFTS), an emerging infectious disease in China. Laboratory mice have been reported to be susceptible to SFTSV infection, but the infection in nonhuman primates has not been investigated. This study is the first to report that, in rhesus macaques, SFTSV does not cause severe symptoms or death but causes fever, thrombocytopenia, leukocytopenia, and increased levels of transaminases and myocardial enzymes in blood. Viremia, virus-specific immunoglobulin M and immunoglobulin G antibodies, and neutralizing antibodies were identified in all infected macaques. Levels of the cytokines interferon ?, eotaxin, tumor necrosis factor ?, and macrophage inflammatory protein 1? were significantly elevated in the blood. Minor pathological lesions were observed in the liver and kidney during the late stages of infection. Overall, SFTSV infection in rhesus macaques resembled mild SFTS in humans. PMID:25326554

Jin, Cong; Jiang, Hong; Liang, Mifang; Han, Ying; Gu, Wen; Zhang, Fushun; Zhu, Hua; Wu, Wei; Chen, Ting; Li, Chuan; Zhang, Weilun; Zhang, Quanfu; Qu, Jing; Wei, Qiang; Qin, Chuan; Li, Dexin

2015-03-15

65

[Epidemiologic aspects of human immunodeficiency virus and hepatitis virus infections].  

PubMed

In order to determinate the prevalence of hepatitis B virus and hepatitis C virus among patients infected by the HIV, We realized a transverse survey case--control in hepato-gastro-enterological ward and serology unity of National Institute of Research in Public health (INRSP). Our sample was constituted with 100 patients HIV positive compared to 100 controls HIV negative. The viral markers research has been made by methods immuno-enzymatiqueses of ELISA 3rd generation. Tests permitted to get the following results: Hepatitis B surface antigen (HBs Ag) was positive among 21% with patients HIV positive versus 23% among control (p = 0,732); Antibody to hepatitis C virus (anti-HCV ab) was present among 23% with patients HIV positive versus 0% among control (p <0,05). Female was predominant among co-infections patient, but without statistic link (p = 0,9 and p = 0,45); The co-infection HBV- HCV was significatively linked to age beyond 40 years (p = 0,0005). Co-infections with HIV infection and hepatitis virus are not rare and deserve to be investigated. PMID:19617082

Diarra, M; Konate, A; Minta, D; Sounko, A; Dembele, M; Toure, C S; Kalle, A; Traore, H H; Maiga, M Y

2006-01-01

66

Mimiviridae: clusters of orthologous genes, reconstruction of gene repertoire evolution and proposed expansion of the giant virus family  

PubMed Central

Background The family Mimiviridae belongs to the large monophyletic group of Nucleo-Cytoplasmic Large DNA Viruses (NCLDV; proposed order Megavirales) and encompasses giant viruses infecting amoeba and probably other unicellular eukaryotes. The recent discovery of the Cafeteria roenbergensis virus (CroV), a distant relative of the prototype mimiviruses, led to a substantial expansion of the genetic variance within the family Mimiviridae. In the light of these findings, a reassessment of the relationships between the mimiviruses and other NCLDV and reconstruction of the evolution of giant virus genomes emerge as interesting and timely goals. Results Database searches for the protein sequences encoded in the genomes of several viruses originally classified as members of the family Phycodnaviridae, in particular Organic Lake phycodnaviruses and Phaeocystis globosa viruses (OLPG), revealed a greater number of highly similar homologs in members of the Mimiviridae than in phycodnaviruses. We constructed a collection of 898 Clusters of Orthologous Genes for the putative expanded family Mimiviridae (MimiCOGs) and used these clusters for a comprehensive phylogenetic analysis of the genes that are conserved in most of the NCLDV. The topologies of the phylogenetic trees for these conserved viral genes strongly support the monophyly of the OLPG and the mimiviruses. The same tree topology was obtained by analysis of the phyletic patterns of conserved viral genes. We further employed the mimiCOGs to obtain a maximum likelihood reconstruction of the history of genes losses and gains among the giant viruses. The results reveal massive gene gain in the mimivirus branch and modest gene gain in the OLPG branch. Conclusions These phylogenomic results reported here suggest a substantial expansion of the family Mimiviridae. The proposed expanded family encompasses a greater diversity of viruses including a group of viruses with much smaller genomes than those of the original members of the Mimiviridae. If the OLPG group is included in an expanded family Mimiviridae, it becomes the only family of giant viruses currently shown to host virophages. The mimiCOGs are expected to become a key resource for phylogenomics of giant viruses. PMID:23557328

2013-01-01

67

Varicella Zoster Virus (Chickenpox) Infection in Pregnancy  

PubMed Central

Congenital varicella syndrome, maternal varicella zoster virus pneumonia and neonatal varicella infection are associated with serious feto-maternal morbidity and not infrequently with mortality. Vaccination against Varicella zoster virus can prevent the disease and outbreak control limits the exposure of pregnant women to the infectious agent. Maternal varicella zoster immune globulin (VZIG) administration before rash development, with or without antivirals medications can modify progression of the disease. PMID:21585641

Lamont, Ronald F.; Sobel, Jack D; Carrington, D; Mazaki-Tovi, Shali; Kusanovic, Juan Pedro; Vaisbuch, Edi; Romero, Roberto

2011-01-01

68

Hematologic Manifestations of Feline Immunodeficiency Virus Infection  

Microsoft Academic Search

Studies were done on 53 cats with community-acquired infection with the feline immunodeficiency virus (FIV) to determine if hematologic abnormalities were comparable with those observed in patients seropositive for the human immunodeficiency virus (HIV). Nine cats were asymptom- atic, 24 had clinical symptoms equivalent to AIDS-related complex (ARC), and 20 had AIDS-like disease. Hematologic abnormalities were detected in 75% (40

Grady H. Shelton; Michael L. Linenberger; Chris K. Grant; Janis L. Abkowitz

69

Analysis of in vivo dynamics of influenza virus infection in mice using a GFP reporter virus  

E-print Network

Analysis of in vivo dynamics of influenza virus infection in mice using a GFP reporter virus Balaji for review December 30, 2009) Influenza A virus is being extensively studied because of its major impact on human and animal health. However, the dynamics of influenza virus infection and the cell types infected

70

Protection of inactivated influenza virus vaccine against lethal influenza virus infection in diabetic mice  

Microsoft Academic Search

Influenza virus infection frequently causes complications and some excess mortality in the patients with diabetes. Vaccination is an effective measure to prevent influenza virus infection. In this paper, antibody response and protection against influenza virus infection induced by vaccination were studied in mouse model of diabetes. Healthy and diabetic BALB\\/c mice were immunized once or twice with inactivated influenza virus

Qiang Zhu; Haiyan Chang; Yan Chen; Fang Fang; Changyong Xue; Fenghua Zhang; Meizhen Qiu; Hanzhong Wang; Bin Wang; Ze Chen

2005-01-01

71

Complete Genome Sequence of Le Blanc Virus, a Third Caenorhabditis Nematode-Infecting Virus  

E-print Network

Complete Genome Sequence of Le Blanc Virus, a Third Caenorhabditis Nematode-Infecting Virus Carl J,a and Institute of Biology of the Ecole Normale Supérieure (IBENS), Paris, Franceb Orsay virus and Santeuil virus, the first known viruses capable of naturally infecting the nematodes Caenorhabditis elegans

Wang, David

72

Influenza virus infection in a compromised immune system   

E-print Network

Severe influenza virus infection, including human infection with highly pathogenic H5N1 viruses is characterised by massive pulmonary inflammation, immunopathology and excessive cytokine production, a process in ...

Campbell, Gillian Mhairi

2012-06-30

73

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 PMID:8464405

Levy, J A

1993-01-01

74

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

75

Parainfluenza virus 5 expressing the g protein of rabies virus protects mice after rabies virus infection.  

PubMed

Rabies remains a major public health threat around the world. Once symptoms appear, there is no effective treatment to prevent death. In this work, we tested a recombinant parainfluenza virus 5 (PIV5) strain expressing the glycoprotein (G) of rabies (PIV5-G) as a therapy for rabies virus infection: we have found that PIV5-G protected mice as late as 6 days after rabies virus infection. PIV5-G is a promising vaccine for prevention and treatment of rabies virus infection. PMID:25552723

Huang, Ying; Chen, Zhenhai; Huang, Junhua; Fu, ZhenFang; He, Biao

2015-03-15

76

Epstein-Barr virus infection mechanisms  

PubMed Central

Epstein-Barr virus (EBV) infection occurs by distinct mechanisms across different cell types. EBV infection of B cells in vitro minimally requires 5 viral glycoproteins and 2 cellular proteins. By contrast, infection of epithelial cells requires a minimum of 3 viral glycoproteins, which are capable of interacting with one or more of 3 different cellular proteins. The full complement of proteins involved in entry into all cell types capable of being infected in vivo is unknown. This review discusses the events that occur when the virus is delivered into the cytoplasm of a cell, the players known to be involved in these events, and the ways in which these players are thought to function. PMID:25322867

Chesnokova, Liudmila S.; Hutt-Fletcher, Lindsey M.

2014-01-01

77

Apoptosis in virus infection dynamics models  

PubMed Central

In this paper, on the basis of the simplified two-dimensional virus infection dynamics model, we propose two extended models that aim at incorporating the influence of activation-induced apoptosis which directly affects the population of uninfected cells. The theoretical analysis shows that increasing apoptosis plays a positive role in control of virus infection. However, after being included the third population of cytotoxic T lymphocytes immune response in HIV-infected patients, it shows that depending on intensity of the apoptosis of healthy cells, the apoptosis can either promote or comfort the long-term evolution of HIV infection. Further, the discrete-time delay of apoptosis is incorporated into the pervious model. Stability switching occurs as the time delay in apoptosis increases. Numerical simulations are performed to illustrate the theoretical results and display the different impacts of a delay in apoptosis. PMID:24963975

Fan, Ruili; Dong, Yueping; Huang, Gang; Takeuchi, Yasuhiro

2014-01-01

78

Apoptosis in virus infection dynamics models.  

PubMed

In this paper, on the basis of the simplified two-dimensional virus infection dynamics model, we propose two extended models that aim at incorporating the influence of activation-induced apoptosis which directly affects the population of uninfected cells. The theoretical analysis shows that increasing apoptosis plays a positive role in control of virus infection. However, after being included the third population of cytotoxic T lymphocytes immune response in HIV-infected patients, it shows that depending on intensity of the apoptosis of healthy cells, the apoptosis can either promote or comfort the long-term evolution of HIV infection. Further, the discrete-time delay of apoptosis is incorporated into the pervious model. Stability switching occurs as the time delay in apoptosis increases. Numerical simulations are performed to illustrate the theoretical results and display the different impacts of a delay in apoptosis. PMID:24963975

Fan, Ruili; Dong, Yueping; Huang, Gang; Takeuchi, Yasuhiro

2014-01-01

79

Virus infections reduce in vitro multiplication of ‘Malling Landmark’ raspberry  

Microsoft Academic Search

Summary  Virus-infected plants are often symptomless and may be inadvertently used as explant sources in tissue culture research. Our\\u000a objective was to determine the effect of virus infection on micropropagation. We studied the effects of single and multiple\\u000a infections of three common raspberry viruses on the in vitro culture of ‘Malling Landmark’ red raspberry (Rubus idaeus L.). Virus-infected reaspberry plants were

Chih-Wei V. Tsao; Joseph D. Postman; Barbara M. Reed

2000-01-01

80

Chronic Hepatitis B Virus Infection and Pregnancy  

PubMed Central

Planning of pregnancy and management of chronic hepatitis B virus during pregnancy includes recognition of maternal virological status, assessment of liver disease severity and minimization of risk for mother to infant transmission of infection. Decisions regarding the use of antivirals during pregnancy need to be individualized. Monitoring for infection and immunization in newborns is also important. For mothers on antiviral therapy, breastfeeding is not recommended.

Kumar, Manoj; Singh, Tarandeep; Sinha, Swati

2012-01-01

81

Control of viruses infecting grapevine.  

PubMed

Grapevine is a high value vegetatively propagated fruit crop that suffers from numerous viruses, including some that seriously affect the profitability of vineyards. Nowadays, 64 viruses belonging to different genera and families have been reported in grapevines and new virus species will likely be described in the future. Three viral diseases namely leafroll, rugose wood, and infectious degeneration are of major economic importance worldwide. The viruses associated with these diseases are transmitted by mealybugs, scale and soft scale insects, or dagger nematodes. Here, we review control measures of the major grapevine viral diseases. More specifically, emphasis is laid on (i) approaches for the production of clean stocks and propagative material through effective sanitation, robust diagnosis, as well as local and regional certification efforts, (ii) the management of vectors of viruses using cultural, biological, and chemical methods, and (iii) the production of resistant grapevines mainly through the application of genetic engineering. The benefits and limitations of the different control measures are discussed with regard to accomplishments and future research directions. PMID:25591880

Maliogka, Varvara I; Martelli, Giovanni P; Fuchs, Marc; Katis, Nikolaos I

2015-01-01

82

The neurobiology of varicella zoster virus infection  

PubMed Central

Varicella zoster virus (VZV) is a neurotropic herpesvirus that infects nearly all humans. Primary infection usually causes chickenpox (varicella), after which virus becomes latent in cranial nerve ganglia, dorsal root ganglia and autonomic ganglia along the entire neuraxis. Although VZV cannot be isolated from human ganglia, nucleic acid hybridization and, later, polymerase chain reaction proved that VZV is latent in ganglia. Declining VZV-specific host immunity decades after primary infection allows virus to reactivate spontaneously, resulting in shingles (zoster) characterized by pain and rash restricted to 1-3 dermatomes. Multiple other serious neurological and ocular disorders also result from VZV reactivation. This review summarizes the current state of knowledge of the clinical and pathological complications of neurological and ocular disease produced by VZV reactivation, molecular aspects of VZV latency, VZV virology and VZV-specific immunity, the role of apoptosis in VZV-induced cell death, and the development of an animal model provided by simian varicella virus infection of monkeys. PMID:21342215

Gilden, D.; Mahalingam, R.; Nagel, M. A.; Pugazhenthi, S.; Cohrs, R. J.

2011-01-01

83

Influenza A virus infections in Chinese landbirds  

E-print Network

Water birds are considered the reservoir for avian infl uenza viruses. We examined this assumption by sampling and real-time reverse transcription–PCR testing of 939 Asian land birds of 153 species. Infl uenza A infection was found, particularly...

Peterson, A. Townsend; Bush, Sarah E.; Spackman, Erica; Swayne, David E.; Ip, Hon S.

2009-10-01

84

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

85

Winter Infections: Influenza, Respiratory Syncytial Virus (RSV)  

E-print Network

in Children #12;Symptoms of RSV is similar to the common cold A person with an RSV infection might cough) ­ Antibiotics do not help! #12;Common Cold (Rhinovirus) Picture: bubblews.com #12;Common Cold Most common viral not give you the common cold! Viruses can be contagious for up to 2-3 weeks!! http://www.cdc.gov/ge

Goldman, Steven A.

86

Pathogenesis of Machupo virus infection in primates*  

PubMed Central

Experimental Machupo virus infection of rhesus and cynomolgus monkeys produced a severe illness consisting of an initial clinical phase and a later neurological phase. Cumulative mortality during the two phases was 80% and 95% respectively. Attempts to alter the pathogenesis with decomplementation or immunosuppression resulted in earlier deaths of the monkeys. PMID:182402

Eddy, G. A.; Scott, S. K.; Wagner, F. S.; Brand, O. M.

1975-01-01

87

Musculoskeletal Manifestations of Human Immunodeficiency Virus Infection  

Microsoft Academic Search

Human immunodeficiency virus (HIV) causes an infection characterized by a wide spectrum of clinical manifestations, including musculoskeletal conditions that have been recognized with increasing frequency in recent years. Arthralgia, usually of moderate intensity, intermittent, and oligoarticular, is the most frequent rheumatic manifestation of HIV; it occurs in approximately 35% of the cases. Knees, shoulders, and elbows are the most frequently

Luis H. Silveira; Luis J. Jara; Píndaro Martínez-Osuna; Luis R. Espinoza; Mitchel J. Seleznick

1991-01-01

88

Giant virus Megavirus chilensis encodes the biosynthetic pathway for uncommon acetamido sugars.  

PubMed

Giant viruses mimicking microbes, by the sizes of their particles and the heavily glycosylated fibrils surrounding their capsids, infect Acanthamoeba sp., which are ubiquitous unicellular eukaryotes. The glycans on fibrils are produced by virally encoded enzymes, organized in gene clusters. Like Mimivirus, Megavirus glycans are mainly composed of virally synthesized N-acetylglucosamine (GlcNAc). They also contain N-acetylrhamnosamine (RhaNAc), a rare sugar; the enzymes involved in its synthesis are encoded by a gene cluster specific to Megavirus close relatives. We combined activity assays on two enzymes of the pathway with mass spectrometry and NMR studies to characterize their specificities. Mg534 is a 4,6-dehydratase 5-epimerase; its three-dimensional structure suggests that it belongs to a third subfamily of inverting dehydratases. Mg535, next in the pathway, is a bifunctional 3-epimerase 4-reductase. The sequential activity of the two enzymes leads to the formation of UDP-l-RhaNAc. This study is another example of giant viruses performing their glycan synthesis using enzymes different from their cellular counterparts, raising again the question of the origin of these pathways. PMID:25035429

Piacente, Francesco; De Castro, Cristina; Jeudy, Sandra; Molinaro, Antonio; Salis, Annalisa; Damonte, Gianluca; Bernardi, Cinzia; Abergel, Chantal; Tonetti, Michela G

2014-08-29

89

A case of Ebola virus infection.  

PubMed Central

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 was mild and may have been modified by treatment with human interferon and convalescent serum. Convalescence was protracted; there was evidence of bone-marrow depression and virus was excreted in low titre for some weeks. Recovery was complete. Infection was contained by barrier-nursing techniques using a negative-pressure plastic isolator and infection did not spread to attendant staff or to the community. PMID:890413

Emond, R T; Evans, B; Bowen, E T; Lloyd, G

1977-01-01

90

Hepatitis B virus infection in children.  

PubMed

For two decades, hepatitis B vaccine has been integrated into national routine childhood vaccination programs in almost all countries. The prevalence of HBsAg has decreased in children worldwide. However, there are children who miss the benefit of hepatitis B vaccine in some regions and countries. Long-term follow-up studies have revealed the clinical outcomes of chronic hepatitis B virus infection in children. A small percentage of chronically infected children develop liver cirrhosis and hepatocellular carcinoma. However, it is controversial who should be treated and when antiviral treatment should be initiated in children. Compared with adult studies, the data are insufficient to evaluate the pathogenesis of hepatitis B infection and the efficacy of antiviral treatment in childhood. New antiviral drugs have been approved for children and adults. Also, oral antiviral drugs are administered to pregnant women to reduce the hepatitis B virus mother-to-child transmission rate. PMID:25724218

Komatsu, Haruki; Inui, Ayano

2015-04-01

91

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

92

Chronic mucocutaneous herpes simplex virus and varicella zoster virus infections.  

PubMed

Chronic herpes simplex virus (CHSV) and chronic varicella zoster virus (CVZV) are defined as atypical mucocutaneous wart-like and/or ulcerative HSV or VZV infections, persisting for at least 1 month. Both are commonly associated with HIV infection and may occasionally present with other types of immunosuppression. CHSV and CVZV occur despite the immune restoration effect of highly active antiretroviral therapy for HIV. The clinical polymorphism of CHSV and CVZV makes recognition difficult. Histology, immunohistology, PCR and viral culture all help to confirm the diagnosis. Treatment is frequently complicated by resistance to thymidine kinase (TK)-dependent antivirals, including acyclovir, valacyclovir and famciclovir. Viral culture remains an essential tool for antiviral drug susceptibility testing. Therapeutic alternatives include non-TK-dependent antivirals, such as foscarnet or cidofovir, which directly target viral DNA polymerase. With few exceptions, CHSV and CVZV infections do not constitute significant risk factors for disseminated cutaneous or systemic infection. This review compares the similarities of and differences between CHSV and CVZV infections. PMID:21056516

Wauters, Odile; Lebas, Eglantine; Nikkels, Arjen F

2012-06-01

93

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

2014-07-01

94

Zebrafish: Modeling for Herpes Simplex Virus Infections  

PubMed Central

Abstract For many years, zebrafish have been the prototypical model for studies in developmental biology. In recent years, zebrafish has emerged as a powerful model system to study infectious diseases, including viral infections. Experiments conducted with herpes simplex virus type-1 in adult zebrafish or in embryo models are encouraging as they establish proof of concept with viral-host tropism and possible screening of antiviral compounds. In addition, the presence of human homologs of viral entry receptors in zebrafish such as 3-O sulfated heparan sulfate, nectins, and tumor necrosis factor receptor superfamily member 14-like receptor bring strong rationale for virologists to test their in vivo significance in viral entry in a zebrafish model and compare the structure–function basis of virus zebrafish receptor interaction for viral entry. On the other end, a zebrafish model is already being used for studying inflammation and angiogenesis, with or without genetic manipulations, and therefore can be exploited to study viral infection-associated pathologies. The major advantage with zebrafish is low cost, easy breeding and maintenance, rapid lifecycle, and a transparent nature, which allows visualizing dissemination of fluorescently labeled virus infection in real time either at a localized region or the whole body. Further, the availability of multiple transgenic lines that express fluorescently tagged immune cells for in vivo imaging of virus infected animals is extremely attractive. In addition, a fully developed immune system and potential for receptor-specific knockouts further advocate the use of zebrafish as a new tool to study viral infections. In this review, we focus on expanding the potential of zebrafish model system in understanding human infectious diseases and future benefits. PMID:24266790

Antoine, Thessicar Evadney; Jones, Kevin S.; Dale, Rodney M.; Shukla, Deepak

2014-01-01

95

Isolation of a monoclonal antibody which blocks vaccinia virus infection.  

PubMed Central

We have isolated a monoclonal antibody, B2, that neutralizes vaccinia virus infection. B2 reacts with a trypsin-sensitive cell surface epitope. B2 does not neutralize infection of herpes simplex virus, suggesting that the B2-reactive epitope is specifically involved in vaccinia virus entry. A survey of 12 different cell lines reveals a correlation between B2 reactivity and susceptibility to vaccinia virus infection. In addition, B2 interferes with vaccinia virus adsorption to target cells. Taken together, the B2-reactive epitope is part of a receptor that appears important for vaccinia virus entry. PMID:7527087

Chang, W; Hsiao, J C; Chung, C S; Bair, C H

1995-01-01

96

Animal models of varicella zoster virus infection.  

PubMed

Primary infection with varicella zoster virus (VZV) results in varicella (chickenpox) followed by the establishment of latency in sensory ganglia. Declining T cell immunity due to aging or immune suppressive treatments can lead to VZV reactivation and the development of herpes zoster (HZ, shingles). HZ is often associated with significant morbidity and occasionally mortality in elderly and immune compromised patients. There are currently two FDA-approved vaccines for the prevention of VZV: Varivax® (for varicella) and Zostavax® (for HZ). Both vaccines contain the live-attenuated Oka strain of VZV. Although highly immunogenic, a two-dose regimen is required to achieve a 99% seroconversion rate. Zostavax vaccination reduces the incidence of HZ by 51% within a 3-year period, but a significant reduction in vaccine-induced immunity is observed within the first year after vaccination. Developing more efficacious vaccines and therapeutics requires a better understanding of the host response to VZV. These studies have been hampered by the scarcity of animal models that recapitulate all aspects of VZV infections in humans. In this review, we describe different animal models of VZV infection as well as an alternative animal model that leverages the infection of Old World macaques with the highly related simian varicella virus (SVV) and discuss their contributions to our understanding of pathogenesis and immunity during VZV infection. PMID:25437040

Haberthur, Kristen; Messaoudi, Ilhem

2013-01-01

97

Animal Models of Varicella Zoster Virus Infection  

PubMed Central

Primary infection with varicella zoster virus (VZV) results in varicella (chickenpox) followed by the establishment of latency in sensory ganglia. Declining T cell immunity due to aging or immune suppressive treatments can lead to VZV reactivation and the development of herpes zoster (HZ, shingles). HZ is often associated with significant morbidity and occasionally mortality in elderly and immune compromised patients. There are currently two FDA-approved vaccines for the prevention of VZV: Varivax® (for varicella) and Zostavax® (for HZ). Both vaccines contain the live-attenuated Oka strain of VZV. Although highly immunogenic, a two-dose regimen is required to achieve a 99% seroconversion rate. Zostavax vaccination reduces the incidence of HZ by 51% within a 3-year period, but a significant reduction in vaccine-induced immunity is observed within the first year after vaccination. Developing more efficacious vaccines and therapeutics requires a better understanding of the host response to VZV. These studies have been hampered by the scarcity of animal models that recapitulate all aspects of VZV infections in humans. In this review, we describe different animal models of VZV infection as well as an alternative animal model that leverages the infection of Old World macaques with the highly related simian varicella virus (SVV) and discuss their contributions to our understanding of pathogenesis and immunity during VZV infection. PMID:25437040

Haberthur, Kristen; Messaoudi, Ilhem

2013-01-01

98

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

99

ANALYSIS OF HEPATITIS C VIRUS INFECTION MODELS WITH HEPATOCYTE HOMEOSTASIS  

E-print Network

ANALYSIS OF HEPATITIS C VIRUS INFECTION MODELS WITH HEPATOCYTE HOMEOSTASIS TIMOTHY C. RELUGA ALAMOS NATIONAL LABORATORY LOS ALAMOS, NM 87545 Abstract. Recently, we developed a model for hepatitis C infections with hepatotropic viruses, such as hepatitis B virus. Key words. HCV, viral dynamics, bifurcation

Reluga, Tim

100

Infection and Activation of Monocytes by Marburg and Ebola Viruses  

Microsoft Academic Search

In this study we investigated the effects of Marburg virus and Ebola virus (species Zaire and Reston) infections on freshly isolated suspended monocytes in comparison to adherent macrophages under culture conditions. Our data showed that monocytes are permissive for both filoviruses. As is the case in macrophages, infection resulted in the activation of monocytes which was largely independent of virus

UTE STROHER; ELMAR WEST; HARALD BUGANY; HANS-DIETER KLENK; HANS-JOACHIM SCHNITTLER; HEINZ FELDMANN

2001-01-01

101

Ebola virus (EboV) infection causes fatal  

E-print Network

Ebola virus (EboV) infection causes fatal haemorrhagic fever with mortality rates exceeding 75 Carette, J. E. et al. Ebola virus entry requires the cholesterol transporter Niemann­Pick C1. Nature 24 is essential for Ebola virus infection. Nature 24 Aug 2011 (doi:10.1038/nature10380) ANTIVIRALS Achilles heel

Chandran, Kartik

102

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)

2006-04-21

103

Methods for assessing feline immunodeficiency virus infection, infectivity and purification.  

PubMed

Infection of cats with the feline immunodeficiency virus (FIV) recapitulates many aspects of infection of humans with HIV, including highly activated but ineffectual immune responses. Infected hosts remain seropositive for life, and detection of antibodies is the mainstay of diagnosis. However, to quantify virus for research or prognosis, viral proteins, nucleic acids or enzymes, are typically measured by ELISA, PCR or activity, respectively. While such assays are in wide use, they do not distinguish whole, infectious viral particles from defective or disrupted viruses. Titers of infectious viral particles may be estimated from tissue culture infectious doses or by enumerating cell-associated viral proteins, viral transcriptional activity or formation of syncytia. To analyze the viral proteome and the incorporation of host components into viral envelopes, pure lentiviral preparations are required. Methods for purifying lentiviruses include ultracentrifugation to separate particles by size, mass and/or density; chromatography to separate particles by charge, affinity or size; and additional removal of extraviral proteins and exosomes through subtilisin digestion or immunoaffinity. This article reviews advantages and disadvantages of different approaches to purification of lentiviruses with special reference to suitability for FIV, and highlights effects of purification on immune responses and immune assays. PMID:21715023

Ammersbach, Melanie; Bienzle, Dorothee

2011-10-15

104

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

105

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

106

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. PMID:23034323

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

2012-01-01

107

Chronic hepatitis B virus infection.  

PubMed

All providers, regardless of specialty, should perform screening for HBV on high-risk persons, especially those born in endemic countries. The primary care physician can perform the initial evaluation and follow-up of patients with chronic HBV by following the algorithm in this article and consulting with specialists when appropriate. Chronically infected patients should be followed on a regular basis, preferably every 6 months, with liver function tests, and when appropriate, HBV DNA levels. Those who meet the criteria for high risk for HCC should undergo liver ultrasound every 6 months. Powerful antiviral medications are available that can suppress but not cure HBV and result in resolution of liver inflammation and fibrosis, even cirrhosis, as well as decrease the risk of developing HCC. They should be used in those patients who meet the criteria outlined in the practice guidelines of the major liver societies. PMID:24266913

McMahon, Brian J

2014-01-01

108

KINETIC PROFILE OF INFLUENZA VIRUS INFECTION IN THREE RAT STRAINS  

EPA Science Inventory

Abstract Influenza infection is a respiratory disease of viral origin that can cause major epidemics in man. The influenza virus infects and damages epithelial cells of the respiratory tract and causes pneumonia. Lung lesions of mice infected with influenza virus resembl...

109

Antibody-Dependent Enhancement of Ebola Virus Infection  

Microsoft Academic Search

Most strains of Ebola virus cause a rapidly fatal hemorrhagic disease in humans, yet there are still no biologic explanations that adequately account for the extreme virulence of these emerging pathogens. Here we show that Ebola Zaire virus infection in humans induces antibodies that enhance viral infectivity. Plasma or serum from convalescing patients enhanced the infection of primate kidney cells

Ayato Takada; Heinz Feldmann; Thomas G. Ksiazek; Yoshihiro Kawaoka

2003-01-01

110

Respiratory Syncytial Virus Infection (RSV): Transmission and Prevention  

MedlinePLUS

... CDC Cancel Submit Search The CDC Respiratory Syncytial Virus Infection (RSV) Note: Javascript is disabled or is ... school or childcare. They can then transmit the virus to other members of the family. RSV can ...

111

Molecular diagnosis of chronic bee paralysis virus infection  

Microsoft Academic Search

A new RT-PCR test was developed for the diagnosis of chronic bee paralysis virus (CBPV) infection. Used in parallel with an experimental infection test, the RT-PCR test was less fas- tidious and allowed the detection of latent CBPV infection in colonies. The new test is based on the fact that clinical CBPV infections (but not latent infections) yield a high

Carole Triboulot; Laetitia Mathieu; Jean-Paul Faucon

2002-01-01

112

Persistent infection with chicken anaemia virus and some effects of highly virulent infectious bursal disease virus infection on its persistency  

Microsoft Academic Search

Chicken anaemia virus (CAV) infectivity and the effect of highly virulent infectious bursal disease virus (hv IBDV) infection on CAV’s infectivity were examined in chickens inoculated withCAV or inoculated dually with CAV and hv IBDV. Five chickens inoculated dually with hv IBDV at 35 days old and then with CAV at 40 days old exhibited no clinical signs of disease,

K. IMAI; M. MASE; K. TSUKAMOTO; H. HIHARA; N. YUASA

1999-01-01

113

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. PMID:24976356

2014-01-01

114

Comparison of intranasal and aerosol infection of mice in assessment of immunity to influenza virus infection.  

PubMed

A comparison was made of intranasal and aerosol routes of infection with X-31 influenza A virus in Balb/c mice. Mice were first infected with 100 MID50 by either route then challenged 42 days later with the same virus given by the same or alternative route. Three days following each infection, pulmonary virus was measured by inoculation of chick embryos. Mice initially infected under ether anesthesia by intranasal inoculation experienced higher initial mortality but proved most resistant to subsequent challenge by either method. In contrast, mice first infected by aerosol were least resistant to intranasal challenge, as indicated by increased rate of infection and pulmonary virus titers, but, like mice previously infected intranasally, were not reinfected by the aerosol route. Thus, intranasal infection appears to be more effective both in inducing and challenging immunity from infection. These results should be considered in the design of experiments utilizing influenza virus infection of mice as a model system. PMID:1666111

Johansson, B E; Kilbourne, E D

1991-11-01

115

Antibody-Dependent Enhancement of Ebola Virus Infection  

PubMed Central

Most strains of Ebola virus cause a rapidly fatal hemorrhagic disease in humans, yet there are still no biologic explanations that adequately account for the extreme virulence of these emerging pathogens. Here we show that Ebola Zaire virus infection in humans induces antibodies that enhance viral infectivity. Plasma or serum from convalescing patients enhanced the infection of primate kidney cells by the Zaire virus, and this enhancement was mediated by antibodies to the viral glycoprotein and by complement component C1q. Our results suggest a novel mechanism of antibody-dependent enhancement of Ebola virus infection, one that would account for the dire outcome of Ebola outbreaks in human populations. PMID:12805454

Takada, Ayato; Feldmann, Heinz; Ksiazek, Thomas G.; Kawaoka, Yoshihiro

2003-01-01

116

Autophagic flux without a block differentiates varicella-zoster virus infection from herpes simplex virus infection.  

PubMed

Autophagy is a process by which misfolded and damaged proteins are sequestered into autophagosomes, before degradation in and recycling from lysosomes. We have extensively studied the role of autophagy in varicella-zoster virus (VZV) infection, and have observed that vesicular cells are filled with >100 autophagosomes that are easily detectable after immunolabeling for the LC3 protein. To confirm our hypothesis that increased autophagosome formation was not secondary to a block, we examined all conditions of VZV infection as well as carrying out two assessments of autophagic flux. We first investigated autophagy in human skin xenografts in the severe combined immunodeficiency (SCID) mouse model of VZV pathogenesis, and observed that autophagosomes were abundant in infected human skin tissues. We next investigated autophagy following infection with sonically prepared cell-free virus in cultured cells. Under these conditions, autophagy was detected in a majority of infected cells, but was much less than that seen after an infected-cell inoculum. In other words, inoculation with lower-titered cell-free virus did not reflect the level of stress to the VZV-infected cell that was seen after inoculation of human skin in the SCID mouse model or monolayers with higher-titered infected cells. Finally, we investigated VZV-induced autophagic flux by two different methods (radiolabeling proteins and a dual-colored LC3 plasmid); both showed no evidence of a block in autophagy. Overall, therefore, autophagy within a VZV-infected cell was remarkably different from autophagy within an HSV-infected cell, whose genome contains two modifiers of autophagy, ICP34.5 and US11, not present in VZV. PMID:25535384

Buckingham, Erin M; Carpenter, John E; Jackson, Wallen; Zerboni, Leigh; Arvin, Ann M; Grose, Charles

2015-01-01

117

Autophagic flux without a block differentiates varicella-zoster virus infection from herpes simplex virus infection  

PubMed Central

Autophagy is a process by which misfolded and damaged proteins are sequestered into autophagosomes, before degradation in and recycling from lysosomes. We have extensively studied the role of autophagy in varicella-zoster virus (VZV) infection, and have observed that vesicular cells are filled with >100 autophagosomes that are easily detectable after immunolabeling for the LC3 protein. To confirm our hypothesis that increased autophagosome formation was not secondary to a block, we examined all conditions of VZV infection as well as carrying out two assessments of autophagic flux. We first investigated autophagy in human skin xenografts in the severe combined immunodeficiency (SCID) mouse model of VZV pathogenesis, and observed that autophagosomes were abundant in infected human skin tissues. We next investigated autophagy following infection with sonically prepared cell-free virus in cultured cells. Under these conditions, autophagy was detected in a majority of infected cells, but was much less than that seen after an infected-cell inoculum. In other words, inoculation with lower-titered cell-free virus did not reflect the level of stress to the VZV-infected cell that was seen after inoculation of human skin in the SCID mouse model or monolayers with higher-titered infected cells. Finally, we investigated VZV-induced autophagic flux by two different methods (radiolabeling proteins and a dual-colored LC3 plasmid); both showed no evidence of a block in autophagy. Overall, therefore, autophagy within a VZV-infected cell was remarkably different from autophagy within an HSV-infected cell, whose genome contains two modifiers of autophagy, ICP34.5 and US11, not present in VZV. PMID:25535384

Buckingham, Erin M.; Carpenter, John E.; Jackson, Wallen; Zerboni, Leigh; Arvin, Ann M.; Grose, Charles

2015-01-01

118

Ebola virus (EBOV) infection: Therapeutic strategies.  

PubMed

Within less than a year after its epidemic started (in December 2013) in Guinea, Ebola virus (EBOV), a member of the filoviridae, has spread over a number of West-African countries (Guinea, Sierra Leone and Liberia) and gained allures that have been unprecedented except by human immunodeficiency virus (HIV). Although EBOV is highly contagious and transmitted by direct contact with body fluids, it could be counteracted by the adequate chemoprophylactic and -therapeutic interventions: vaccines, antibodies, siRNAs (small interfering RNAs), interferons and chemical substances, i.e. neplanocin A derivatives (i.e. 3-deazaneplanocin A), BCX4430, favipiravir (T-705), endoplasmic reticulum (ER) ?-glucosidase inhibitors and a variety of compounds that have been found to inhibit EBOV infection blocking viral entry or by a mode of action that still has to be resolved. Much has to be learned from the mechanism of action of the compounds active against VSV (vesicular stomatitis virus), a virus belonging to the rhabdoviridae, that in its mode of replication could be exemplary for the replication of filoviridae. PMID:25481298

De Clercq, Erik

2015-01-01

119

Nipah virus infection in bats (order Chiroptera) in peninsular Malaysia.  

PubMed Central

Nipah virus, family Paramyxoviridae, caused disease in pigs and humans in peninsular Malaysia in 1998-99. Because Nipah virus appears closely related to Hendra virus, wildlife surveillance focused primarily on pteropid bats (suborder Megachiroptera), a natural host of Hendra virus in Australia. We collected 324 bats from 14 species on peninsular Malaysia. Neutralizing antibodies to Nipah virus were demonstrated in five species, suggesting widespread infection in bat populations in peninsular Malaysia. PMID:11384522

Yob, J. M.; Field, H.; Rashdi, A. M.; Morrissy, C.; van der Heide, B.; Rota, P.; bin Adzhar, A.; White, J.; Daniels, P.; Jamaluddin, A.; Ksiazek, T.

2001-01-01

120

Identification of Type I IFN in Chinese giant salamander (Andrias davidianus) and the response to an iridovirus infection.  

PubMed

The type I IFNs play a major role in the first line of defense against virus infections. In this study, the type I IFN gene designated gsIFN was identified and characterized in the Chinese giant salamander (Andrias davidianus). The genomic DNA of gsIFN contains 5 exons and 4 introns and has a total length of 5622bp. The full-length cDNA sequence of gsIFN is 1113bp and encodes a putative protein of 186 amino acids that has a 43% identity to type I IFN of Xenopus tropicalis. The deduced amino acid sequence has the C-terminal CAWE motif, that is mostly conserved in the higher vertebrate type I IFNs. Real-time fluorescence quantitative RT-PCR analysis revealed broad expression of gsIFN in vivo and the highest level expression in blood, kidney and spleen. Additionally, the expression of gsIFN at the mRNA level was significantly induced in peripheral blood leucocytes after stimulation with poly I:C and after infection with the Chinese giant salamander iridovirus (GSIV). A plasmid expressing gsIFN was constructed and transfected into the Chinese giant salamander muscle cell line. Expression of the IFN-inducible gene Mx was up-regulated in the gsIFN-overexpressing cells after GSIV infection. The virus load and titer were significantly reduced compared with that in control cells. Additionally, a lower level of virus major capsid protein synthesis was confirmed by immunofluorescence assay compared to the control cells. These results suggest that the gsIFN gene plays an important role in the antiviral innate immune response. PMID:25733388

Chen, Qian; Ma, Jie; Fan, Yuding; Meng, Yan; Xu, Jin; Zhou, Yong; Liu, Wenzhi; Zeng, Xianhui; Zeng, Lingbing

2015-06-01

121

Spatiotemporal Analysis of Hepatitis C Virus Infection  

PubMed Central

Hepatitis C virus (HCV) entry, translation, replication, and assembly occur with defined kinetics in distinct subcellular compartments. It is unclear how HCV spatially and temporally regulates these events within the host cell to coordinate its infection. We have developed a single molecule RNA detection assay that facilitates the simultaneous visualization of HCV (+) and (?) RNA strands at the single cell level using high-resolution confocal microscopy. We detect (+) strand RNAs as early as 2 hours post-infection and (?) strand RNAs as early as 4 hours post-infection. Single cell levels of (+) and (?) RNA vary considerably with an average (+):(?) RNA ratio of 10 and a range from 1–35. We next developed microscopic assays to identify HCV (+) and (?) RNAs associated with actively translating ribosomes, replication, virion assembly and intracellular virions. (+) RNAs display a defined temporal kinetics, with the majority of (+) RNAs associated with actively translating ribosomes at early times of infection, followed by a shift to replication and then virion assembly. (?) RNAs have a strong colocalization with NS5A, but not NS3, at early time points that correlate with replication compartment formation. At later times, only ~30% of the replication complexes appear to be active at a given time, as defined by (?) strand colocalization with either (+) RNA, NS3, or NS5A. While both (+) and (?) RNAs colocalize with the viral proteins NS3 and NS5A, only the plus strand preferentially colocalizes with the viral envelope E2 protein. These results suggest a defined spatiotemporal regulation of HCV infection with highly varied replication efficiencies at the single cell level. This approach can be applicable to all plus strand RNA viruses and enables unprecedented sensitivity for studying early events in the viral life cycle. PMID:25822891

Shulla, Ana; Randall, Glenn

2015-01-01

122

ROLE OF MONOCYTES IN RESPIRATORY SYNCTIAL VIRUS (RSV) INFECTION.  

EPA Science Inventory

ROLE OF MONOCYTES IN RESPIRATORY SYNCYTIAL VIRUS (RSV) INFECTION. Joleen M. Soukup and Susanne Becker, National Health and Environmental Effects Research Laboratory, US EPA, Research Traingle Park, NC USA. RSV infection in airway epithelial cells (EC) results i...

123

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

124

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. PMID:24708791

2014-01-01

125

Araçatuba Virus: A Vaccinialike Virus Associated with Infection in Humans and Cattle  

Microsoft Academic Search

We describe a vaccinialike virus, Araçatuba virus, associ- ated with a cowpoxlike outbreak in a dairy herd and a related case of human infection. Diagnosis was based on virus growth characteristics, electron microscopy, and molecular biology techniques. Molecular characterization of the virus was done by using polymerase chain reaction amplification, cloning, and DNA sequencing of conserved orthopoxvirus genes such as

Giliane de Souza Trindade; Flávio Guimarães da Fonseca; João Trindade Marques; Maurício Lacerda Nogueira; Luiz Claudio; Nogueira Mendes; Alexandre Secorun Borges; Juliana Regina Peiró; Edviges Maristela Pituco; Cláudio Antônio Bonjardim; Paulo César Peregrino Ferreira; Erna Geessien Kroon

2003-01-01

126

78 FR 33848 - Draft Guidance for Industry on Human Immunodeficiency Virus-1 Infection: Developing...  

Federal Register 2010, 2011, 2012, 2013, 2014

...for Industry on Human Immunodeficiency Virus-1 Infection: Developing Antiretroviral...industry entitled ``Human Immunodeficiency Virus-1 Infection: Developing Antiretroviral...industry entitled ``Human Immunodeficiency Virus-1 Infection: Developing...

2013-06-05

127

77 FR 30293 - Recommendations for the Identification of Hepatitis C Virus (HCV) Chronic Infection  

Federal Register 2010, 2011, 2012, 2013, 2014

...Recommendations for the Identification of Hepatitis C Virus (HCV) Chronic Infection AGENCY: Centers...SUPPLEMENTARY INFORMATION: Hepatitis C virus infection is a contagious liver disease...results from infection with the hepatitis C virus (HCV), which is spread primarily...

2012-05-22

128

In-vitro infection of chronic lymphocytic leukemia cells by Epstein-Barr virus (EBV).  

PubMed

We sought to determine the potential of infecting lymphoid cells from patients with chronic leukemia (CLL) with Epstein-Barr virus (EBV) by testing for EBV receptors (EBVR) by flow cytometry, assessing for infectability of these cells by culturing with B95-8-derived virus, and staining for EB nuclear-associated antigens (EBNA) at various times post-infection. EBVR were present on 54-91% of lymphoid cells in seven cases of CLL and on 46% of prolymphocytic leukemia cells. Dynamic changes regarding EBNA positivity, morphology, and viability occurred post-infection with the virus. On day 2 only a few EBNA-positive lymphoblasts were observed. On days 11-21 positivity increased from 2 to 34% of cells. Simultaneously, the viable cell number declined to approximately 1/10th of original number. A significant proportion of the EBNA-positive cells corresponded to the original CLL cells. In 3 of 7 cases of CLL a Pan T-cell phenotype was demonstrated by Leu-1 monoclonal antibody testing. The infected cells did not react with two monoclonal antibodies, EBV-CS 1 and 4, which react with B-cell lymphoblastoid cell lines (B-LCL). Moreover, the B-LCL derived at 1-2 months post-infection of CLL cells did not express the Leu-1 antigen, but expressed EBV-CS 1 or 4 defined antigens. In the prolymphocytic leukemia, 64% of the cells showed EBNA positivity on day 7 and giant cells with huge round or multiple nuclei appeared which were EBNA-positive. CLL and prolymphocytic leukemia cells can be infected as demonstrated by EBNA-positivity. This infection does not lead to immediate transformation, but evokes lymphoblast and multinucleated giant cell production prior to the death of cells. PMID:3512923

Tatsumi, E; Harada, S; Bechtold, T; Lipscomb, H; Davis, J; Kuszynski, C; Volsky, D J; Han, T; Armitage, J; Purtilo, D T

1986-01-01

129

Hepatitis C virus infection in the human immunodeficiency virus infected patient  

PubMed Central

Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) share the same transmission routes; therefore, coinfection is frequent. An estimated 5-10 million individuals alone in the western world are infected with both viruses. The majority of people acquire HCV by injection drug use and, to a lesser extent, through blood transfusion and blood products. Recently, there has been an increase in HCV infections among men who have sex with men. In the context of effective antiretroviral treatment, liver-related deaths are now more common than Acquired Immune Deficiency Syndrome-related deaths among HIV-HCV coinfected individuals. Morbidity and mortality rates from chronic HCV infection will increase because the infection incidence peaked in the mid-1980s and because liver disease progresses slowly and is clinically silent to cirrhosis and end-stage-liver disease over a 15-20 year time period for 15%-20% of chronically infected individuals. HCV treatment has rapidly changed with the development of new direct-acting antiviral agents; therefore, cure rates have greatly improved because the new treatment regimens target different parts of the HCV life cycle. In this review, we focus on the epidemiology, diagnosis and the natural course of HCV as well as current and future strategies for HCV therapy in the context of HIV-HCV coinfection in the western world. PMID:25232248

Clausen, Louise Nygaard; Lundbo, Lene Fogt; Benfield, Thomas

2014-01-01

130

Update on hepatitis B virus infection  

PubMed Central

Chronic infection with hepatitis B virus (HBV) leads to the development of hepatocellular carcinoma and/or chronic liver failure. Despite extensive research, the immunopathogenesis is not completely understood. Viral persistence and clinical outcomes following HBV infection depend on viral factors and host factors; including genetic factors that determine a host’s immune mechanisms. The primary goal of chronic hepatitis B (CHB) treatment is to eradicate HBV or to at least maintain suppression of HBV replication. Despite recent advances in anti-viral agents for chronic HBV infection, complete eradication of the virus has been difficult to achieve. Agents for the treatment of CHB are divided mainly into two groups: immunomodulating agents and antiviral nucleos(t)ide analogues (NAs). Although NAs are safe, effective and easily administered orally, their long-term use poses the risk of drug resistance. Currently, international evidence-based guidelines have been developed to support physicians in managing CHB patients. However, treatment of patients with drug resistance is still challenging, as only a few classes of anti-HBV drugs are available and cross-resistance between drugs can occur. In addition, as the currently available genotypic test for detection of drug resistance still has limitations in identifying the different substitutions present in the same viral genome, the development of a new virologic test to overcome this limitation is necessary. Among the predictive factors associated with response to pegylated interferon (PEG-IFN) therapy, hepatitis B surface antigen quantification is considered to be a surrogate marker for monitoring response to PEG-IFN. Current practice guidelines stress the importance of profound and durable HBV viral suppression in the treatment of CHB patients. To this end, it is essential to choose a potent antiviral drug with a low risk of resistance for initial treatment of CHB to achieve sustained virological response. This review highlights recent advances in the understanding of the immunopathogenesis of HBV and currently available and developing treatment strategies against HBV infection. PMID:25309066

You, Chan Ran; Lee, Sung Won; Jang, Jeong Won; Yoon, Seung Kew

2014-01-01

131

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...

132

Pathogenesis of Respiratory Syncytial Virus Infection in the Murine Model  

Microsoft Academic Search

There is a wide spectrum of illness caused by respiratory syncytial virus (RSV) infection that is caused in large part by host-related factors, such as age of the patient and degree of host immunocom- petency. Although the vast majority of persons infected with RSV experience symptoms of mild upper respiratory tract infection, in some people these infections cause significant morbidity

R. Stokes Peebles; Barney S. Graham

2005-01-01

133

Diagnosis and clinical significance of parainfluenza virus infections in children  

PubMed Central

The diagnosis and clinical features of parainfluenza virus infections are described in 151 children admitted to hospital over a 2-year period. Immunofluorescence was the most sensitive method of laboratory diagnosis, while virus isolation in tissue culture was more often achieved from nasopharyngeal secretions than from cough/nasal swabs. Parainfluenza viruses were responsible for approximately 9% of 1603 acute respiratory admissions. Croup was the commonest of the wide range of respiratory illnesses associated with these infections; in a series of 132 children with croup, a parainfluenza virus was identified in 42%. 24 of the 151 children presented with febrile convulsions, and in a series of 209 children admitted with febrile convulsions, parainfluenza viruses were responsible for 11%. 3 of the children died in hospital with their parainfluenza virus infections, and in addition there was one instance of a close association between parainfluenza virus type 3 infection and the sudden unexpected death of an infant at home. Parainfluenza virus types 4a and 4b, which have so far rarely been identified, were isolated from 16 children. The age distribution and seasonal patterns of the infections are described. Attention is drawn to the risks of cross-infection by parainfluenza viruses in children's wards, and the finding that virus is commonly excreted for at least a week after the onset of the illness. PMID:4361892

Downham, M. A. P. S.; McQuillin, J.; Gardner, P. S.

1974-01-01

134

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 10 fg/?l of viral RNA under monoplex conditions and 10 pg/?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

135

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

136

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. PMID:24944567

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

2014-01-01

137

Revisiting the genome packaging in viruses with lessons from the "Giants".  

PubMed

Genome encapsidation is an essential step in the life cycle of viruses. Viruses either use some of the most powerful ATP-dependent motors to compel the genetic material into the preformed capsid or make use of the positively charged proteins to bind and condense the negatively charged genome in an energy-independent manner. While the former is a hallmark of large DNA viruses, the latter is commonly seen in small DNA and RNA viruses. Discoveries of many complex giant viruses such as mimivirus, megavirus, pandoravirus, etc., belonging to the nucleo-cytoplasmic large DNA virus (NCLDV) superfamily have changed the perception of genome packaging in viruses. From what little we have understood so far, it seems that the genome packaging mechanism in NCLDVs has nothing in common with other well-characterized viral packaging systems such as the portal-terminase system or the energy-independent system. Recent findings suggest that in giant viruses, the genome segregation and packaging processes are more intricately coupled than those of other viral systems. Interestingly, giant viral packaging systems also seem to possess features that are analogous to bacterial and archaeal chromosome segregation. Although there is a lot of diversity in terms of host range, type of genome, and genome size among viruses, they all seem to use three major types of independent innovations to accomplish genome encapsidation. Here, we have made an attempt to comprehensively review all the known viral genome packaging systems, including the one that is operative in giant viruses, by proposing a simple and expanded classification system that divides the viral packaging systems into three large groups (types I-III) on the basis of the mechanism employed and the relatedness of the major packaging proteins. Known variants within each group have been further classified into subgroups to reflect their unique adaptations. PMID:24998349

Chelikani, Venkata; Ranjan, Tushar; Kondabagil, Kiran

2014-10-01

138

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. PMID:24976694

Carrozzo, Marco; Scally, Kara

2014-01-01

139

NATURAL DUCK HEPATITIS B VIRUS INFECTION IN AUSTRALIA  

Microsoft Academic Search

Natural Duck Hepatitis B Virus (DHBV) infection has been studied in Australian ducks. Sera from 430 Pekin Aylesbury cross-bred ducks taken from three separate flocks were examined for duck hepatitis B virus (DHBV) DNA using a DNA dot hybridisation assay. In one flock there was significant infection with DHBV (98\\/140), but none was detectable in the other two flocks. Episomal

JS Freiman; YE Cossart

1986-01-01

140

Porcine reproductive and respiratory syndrome virus: a persistent infection  

Microsoft Academic Search

Persistent infection with porcine reproductive and respiratory syndrome virus (PRRSV) was shown in experimentally infected pigs by isolation of virus from oropharyngeal samples for up to 157 days after challenge. Four 4 week old, conventional, PRRSV antibody-negative pigs were intranasally inoculated with PRRSV (ATCC VR-2402). Serum samples were collected every 2 to 3 days until day 42 post inoculation (PI),

R. W. Wills; J. J. Zimmerman; K.-J. Yoon; S. L. Swenson; M. J. McGinley; H. T. Hill; K. B. Platt; J. Christopher-Hennings; E. A. Nelson

1997-01-01

141

Live Bivalent Vaccine for Parainfluenza and Influenza Virus Infections  

Microsoft Academic Search

Influenza and human parainfluenza virus infections are of both medical and economical importance. Currently, inactivated vaccines provide suboptimal protection against influenza, and vaccines for human parainfluenza virus infection are not available, underscoring the need for new vaccines against these respi- ratory diseases. Furthermore, to reduce the burden of vaccination, the development of multivalent vaccines is highly desirable. Thus, to devise

Yasuko Maeda; Masato Hatta; Ayato Takada; Tokiko Watanabe; Hideo Goto; Gabriele Neumann; Yoshihiro Kawaoka

2005-01-01

142

Zika Virus Infection Acquired During Brief Travel to Indonesia  

PubMed Central

Zika virus infection closely resembles dengue fever. It is possible that many cases are misdiagnosed or missed. We report a case of Zika virus infection in an Australian traveler who returned from Indonesia with fever and rash. Further case identification is required to determine the evolving epidemiology of this disease. PMID:23878182

Kwong, Jason C.; Druce, Julian D.; Leder, Karin

2013-01-01

143

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. PMID:22469474

Akinci, Esragül; Ascioglu, Sibel; Öngürü, Pinar; Uyar, Yavuz

2012-01-01

144

Comparative pathology of select agent influenza A virus infections  

Technology Transfer Automated Retrieval System (TEKTRAN)

Influenza A virus infections may spread rapidly in human populations and cause acute respiratory disease with variable mortality. Two of these influenza viruses have been designated as select agents because of the high case fatality rate: 1918 H1N1 virus and highly pathogenic avian influenza (HPAI) ...

145

Review article Pseudorabies virus infections in pigs. Role of viral  

E-print Network

Review article Pseudorabies virus infections in pigs. Role of viral proteins in virulence on the biological functions of pseudorabies virus (PRV) proteins. It focuses on the role of PRV proteins the spread of genetically engineered vaccine strains within pigs or between pigs. pseudorabies virus protein

Paris-Sud XI, Université de

146

Highly pathogenic avian influenza virus infection in feral raccoons, Japan.  

PubMed

Although raccoons (Procyon lotor) are susceptible to influenza viruses, highly pathogenic avian influenza virus (H5N1) infection in these animals has not been reported. We performed a serosurvey of apparently healthy feral raccoons in Japan and found specific antibodies to subtype H5N1 viruses. Feral raccoons may pose a risk to farms and public health. PMID:21470469

Horimoto, Taisuke; Maeda, Ken; Murakami, Shin; Kiso, Maki; Iwatsuki-Horimoto, Kiyoko; Sashika, Mariko; Ito, Toshihiro; Suzuki, Kazuo; Yokoyama, Mayumi; Kawaoka, Yoshihiro

2011-04-01

147

Pathogenesis and pathobiology of avian influenza virus infection in birds  

Technology Transfer Automated Retrieval System (TEKTRAN)

Avian Influenza (AI) viruses vary in their ability to produce infection, disease and death in different bird species. Based on the pathobiological features in chickens, AI viruses are categorized as, low (LP) and high pathogenicity (HP). Typically, LPAI (low pathogenicity avian influenza) viruses ...

148

A framework for modelling trojans and computer virus infection  

E-print Network

A framework for modelling trojans and computer virus infection Harold Thimbleby1 , Stuart Anderson2 world, including the possibility of Trojan Horse programs and computer viruses, as simply a finite realisation of a Turing Machine. We consider the actions of Trojan Horses and viruses in real computer systems

Cairns, Paul

149

Pathobiology of avian influenza virus infections in wild birds  

Technology Transfer Automated Retrieval System (TEKTRAN)

Individual avian Influenza (AI) viruses vary in their ability to produce infection, disease and death in different bird species. Based on the pathobiological features in chickens, AI viruses (AIV) are categorized as low pathogenicity (LPAI) or high pathogenicity (HPAI) viruses, and can be of any of...

150

Infectivity-Enhancing Antibodies to Ebola Virus Glycoprotein  

Microsoft Academic Search

Ebola virus causes severe hemorrhagic fever in primates, resulting in mortality rates of up to 100%, yet there are no satisfactory biologic explanations for this extreme virulence. Here we show that antisera produced by DNA immunization with a plasmid encoding the surface glycoprotein (GP) of the Zaire strain of Ebola virus enhances the infectivity of vesicular stomatitis virus pseudotyped with

AYATO TAKADA; SHINJI WATANABE; KATSUNORI OKAZAKI; HIROSHI KIDA; Y. Kawaoka

2001-01-01

151

Generating Aptamers for Recognition of Virus-Infected Cells  

PubMed Central

Background The development of molecular probes capable of recognizing virus-infected cells is essential to meet the serious clinical, therapeutic, and national-security challenges confronting virology today. We report the development of DNA aptamers as probes for the selective targeting of virus-infected living cells. Methods To create aptamer probes capable of recognizing virus-infected cells, we used cell-SELEX (systematic evolution of ligands via exponential enrichment), which uses intact infected live cells as targets for aptamer selection. In this study, vaccinia virusinfected and –uninfected lung cancer A549 cells were chosen to develop our model probes. Results A panel of aptamers has been evolved by means of the infected cell–SELEX procedure. The results demonstrate that the aptamers bind selectively to vaccinia virus–infected A549 cells with apparent equilibrium dissociation constants in the nanomolar range. In addition, these aptamers can specifically recognize a variety of target infected cell lines. The aptamers' target is most likely a viral protein located on the cell surface. Conclusions The success of developing a panel of DNA-aptamer probes capable of recognizing virus-infected cells via a whole living cell–SELEX selection strategy may increase our understanding of the molecular signatures of infected cells. Our findings suggest that aptamers can be developed as molecular probes for use as diagnostic and therapeutic reagents and for facilitating drug delivery against infected cells. PMID:19246617

Tang, Zhiwen; Parekh, Parag; Turner, Pete; Moyer, Richard W.; Tan, Weihong

2013-01-01

152

Characterization of a UDP-N-acetylglucosamine biosynthetic pathway encoded by the giant DNA virus Mimivirus.  

PubMed

Mimivirus is a giant DNA virus belonging to the Megaviridae family and infecting unicellular Eukaryotes of the genus Acanthamoeba. The viral particles are characterized by heavily glycosylated surface fibers. Several experiments suggest that Mimivirus and other related viruses encode an autonomous glycosylation system, forming viral glycoproteins independently of their host. In this study, we have characterized three Mimivirus proteins involved in the de novo uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) production: a glutamine-fructose-6-phosphate transaminase (CDS L619), a glucosamine-6-phosphate N-acetyltransferase (CDS L316) and a UDP-GlcNAc pyrophosphorylase (CDS R689). Sequence and enzymatic analyses have revealed some unique features of the viral pathway. While it follows the eukaryotic-like strategy, it also shares some properties of the prokaryotic pathway. Phylogenetic analyses revealed that the Megaviridae enzymes cluster in monophyletic groups, indicating that they share common ancestors, but did not support the hypothesis of recent acquisitions from one of the known hosts. Rather, viral clades branched at deep nodes in phylogenetic trees, forming independent clades outside sequenced cellular organisms. The intermediate properties between the eukaryotic and prokaryotic pathways, the phylogenetic analyses and the fact that these enzymes are shared between most of the known members of the Megaviridae family altogether suggest that the viral pathway has an ancient origin, resulting from lateral transfers of cellular genes early in the Megaviridae evolution, or from vertical inheritance from a more complex cellular ancestor (reductive evolution hypothesis). The identification of a virus-encoded UDP-GlcNAc pathway reinforces the concept that GlcNAc is a ubiquitous sugar representing a universal and fundamental process in all organisms. PMID:24107487

Piacente, Francesco; Bernardi, Cinzia; Marin, Margherita; Blanc, Guillaume; Abergel, Chantal; Tonetti, Michela G

2014-01-01

153

Identification of a role for nucleolin in rabies virus infection.  

PubMed

Rabies virus replicates in the cytoplasm of host cells, but rabies virus phosphoprotein (P-protein) undergoes active nucleocytoplasmic trafficking. Here we show that the largely nuclear P-protein isoform P3 can localize to nucleoli and forms specific interactions with nucleolin. Importantly, depletion of nucleolin expression inhibits viral protein expression and infectious virus production by infected cells. This provides the first evidence that lyssaviruses interact with nucleolin and that nucleolin is important to lyssavirus infection. PMID:25428867

Oksayan, S; Nikolic, J; David, C T; Blondel, D; Jans, D A; Moseley, G W

2015-02-01

154

Human immunodeficiency virus can productively infect cultured human glial cells.  

PubMed Central

Six isolates of the human immunodeficiency virus (HIV) showed differences in their ability to productively infect glioma-derived cell lines and early-passage human brain cell cultures. Susceptibility to HIV infection correlated well with the expression of the astrocyte marker glial fibrillary acidic protein. The CD4 molecule was expressed on some, but not all, of the brain-derived cells; however, no correlation was observed between CD4 protein expression and susceptibility to virus infection. The results show that HIV can productively infect human brain cells, particularly those of glial origin, and suggest that these cell types in the brain can harbor the virus. Images PMID:3472222

Cheng-Mayer, C; Rutka, J T; Rosenblum, M L; McHugh, T; Stites, D P; Levy, J A

1987-01-01

155

Infection with a plant virus modifies vector feeding behavior  

PubMed Central

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.

2011-01-01

156

Cellular immunity and memory to respiratory virus infections  

Microsoft Academic Search

Respiratory virus infections, such as those caused by influenza and parainfluenza viruses, are a major cause of morbidity\\u000a and mortality worldwide. Current vaccines against these pathogensrely on the induction of humoral immune responses that target\\u000a viral coat proteins. Although this type of immunity provides solid protection against homologous virus strains, it is ineffective\\u000a against heterologous virus strains that express serologically

David L. Woodland; R. Jeffrey Hogan; Weimin Zhong

2001-01-01

157

Electron microscope evidence of virus infection in cultured marine fish  

NASA Astrophysics Data System (ADS)

Electron microscope investigation on the red sea bream ( Pagrosomus major), bastard halibut ( Paralichthys olivaceus) and stone flounder ( Kareius bicoloratus) in North China revealed virus infection in the bodies of the dead and diseased fish. These viruses included the lymphocystis disease virus (LDV), parvovirus, globular virus, and a kind of baculavirus which was not discovered and reported before and is now tentatively named baculavirus of stone flounder ( Kareius bicoloratus).

Sun, Xiu-Qin; Zhang, Jin-Xing; Qu, Ling-Yun

2000-09-01

158

Species-Specific, Postentry Barriers to Primate Immunodeficiency Virus Infection  

Microsoft Academic Search

By using replication-defective vectors derived from human immunodeficiency virus type 1 (HIV-1), simian immunodeficiency virus (SIVmac), and murine leukemia virus (MuLV), all of which were pseudotyped with the vesicular stomatitis virus (VSV) G glycoprotein, the efficiency of postentry, early infection events was examined in target cells of several mammalian species. Titers of HIV-1 vectors were significantly lower than those of

WOLFGANG HOFMANN; DAVID SCHUBERT; JASON LABONTE; LINDA MUNSON; SUSAN GIBSON; JONATHAN SCAMMELL; PAUL FERRIGNO; JOSEPH SODROSKI

1999-01-01

159

Neuralgic amyotrophy and hepatitis E virus infection  

PubMed Central

Objective: To determine whether there is an association between an acute preceding hepatitis E virus (HEV) infection and neuralgic amyotrophy (NA), and if so, whether patients with HEV-related NA differ from patients without an associated HEV infection. Methods: HEV testing was conducted in a retrospective cohort of 28 Cornish patients with NA (2011–2013) and a prospective cohort of 38 consecutive Dutch patients with NA (2004–2007). Acute-phase serum samples were analyzed for the presence of anti-HEV immunoglobulin (Ig) M and IgG and HEV RNA (quantitative real-time PCR). Results: Five cases (10.6%) of acute hepatitis E infection were identified in a total group of 47 patients with NA of whom serum samples were available. In 4 patients, HEV RNA was detected in serum samples taken at presentation. All patients with HEV-associated NA had clinical and electrophysiologic evidence of bilateral brachial plexus involvement. Anti-HEV IgM positivity was not related to age, sex, disease severity, disease course, or outcome. Conclusions: Acute hepatitis E is found in 10% of patients with NA from the United Kingdom and the Netherlands. Further research is required to investigate the role of HEV in NA in other geographical locations and to determine pathophysiologic mechanisms. PMID:24401685

van Eijk, Jeroen J.J.; Madden, Richie G.; van der Eijk, Annemiek A.; Hunter, Jeremy G.; Reimerink, Johan H.J.; Bendall, Richard P.; Pas, Suzan D.; Ellis, Vic; van Alfen, Nens; Beynon, Laura; Southwell, Lucy; McLean, Brendan; Jacobs, Bart C.; van Engelen, Baziel G.M.

2014-01-01

160

Hepatitis C virus infection and glomerular disease.  

PubMed

The association between hepatitis C virus (HCV) infection and chronic kidney disease (CKD) is well established and remains an area of intense research. HCV infection is associated with a large spectrum of histo-pathological lesions in both native and transplanted kidneys. The frequency of kidney damage in HCV-infected patients appears low even if is not fully detailed. The most frequent HCV-associated renal lesion is type I membrano-proliferative glomerulonephritis, usually in the context of type II mixed cryoglobulinemia. Various approaches have been tried for the treatment of HCV-related glomerulonephritis, including immunosuppressive therapy (corticosteroids and cytotoxic agents), plasma exchange and antiviral agents. Antiviral treatment of HCV-associated glomerulonephritis has shown encouraging results. Immunosuppressive therapy is particularly recommended for cryoglobulinemic kidney disease. Two distinct approaches should be considered for the treatment of HCV-associated cryoglobulinemic glomerulonephritis according to the level of proteinuria and kidney failure. Some evidence on rituximab therapy for HCV-related cryoglobulinemic glomerulonephritis exists but several questions related to its use need to be addressed. PMID:24988205

Fabrizi, F; Donato, F; Messa, P

2014-06-01

161

Limited Hepatitis B Virus Replication Space in the Chronically Hepatitis C Virus-Infected Liver  

PubMed Central

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

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

2014-01-01

162

Respiratory syncytial virus infection in north-east England.  

PubMed Central

During a period covering four winter epidemics 987 respiratory syncytial (RS) virus infections were identified in the children's wards that served a total population of about 875 000 in north-east England. The incidence of admission to hospital with RS virus infection tended to be twice as high among children in Tyneside as that among children from the rest of the catchment area. The risk of hospital admission with RS virus infection in the first year of life for city children was about 1 in 50. The risk tended to be increased when there was a high proportion of children in the population, overcrowded housing, and unemployment. There was no clear relation between climatic changes and the onset or progress of epidemics. Thirteen deaths associated with RS virus infection were identified, four of them sudden and unexpected at home, and nine of them in children with congenital or acquired abnormalities. Twelve children were admitted twice with distinct RS virus infections; the relative severity of their two illnesses depended on age. Hospital cross-infection accounted for 60 of the 987 illnesses. Large families and overcrowding among poorer families seem to lead to a higher incidence of RS virus infection, and measures to reduce overcrowding and improve housing should help to reduce the spread of infection. Breast-feeding also protects infants from infection, but further information is needed to pinpoint the infants at greater risk and how they may best be protected. PMID:990783

Sims, D G; Downham, M A; McQuillin, J; Gardner, P S

1976-01-01

163

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. PMID:24904547

Chan, Shiu-Wan

2014-01-01

164

Determination of the infection pressure of potato virus Y N  

Microsoft Academic Search

In 1976 consecutive series of plants ofNicotiana tabacum ‘White Burley’ replaced weekly, were used as bait plants to determine the infection pressure of potato virus YN (PVYN) in a crop of ware potatoes in the centre of the Netherlands. The first PVYN-infected tobacco plants were found mid May. The course of infection of the tobacco plants was not correlated with

H. A. van Hoof

1977-01-01

165

Estimating progression to cirrhosis in chronic hepatitis C virus infection  

Microsoft Academic Search

To gain a clearer understanding of the rate of progression to cirrhosis and its determinants in chronic hepatitis C virus (HCV) infection, a systematic review of published epidemiologic studies that incorporated assessment for cirrhosis has been undertaken. Inclusion criteria were more than 20 cases of chronic HCV infection, and information on either age of subjects or duration of infection. Of

Anthony J. Freeman; Gregory J. Dore; Matthew G. Law; Max Thorpe; Jan Von Overbeck; Andrew R. Lloyd; George Marinos; John M. Kaldor

2001-01-01

166

Development of vaccines for prevention of Ebola virus infection.  

PubMed

Ebola virus infection causes severe hemorrhagic fevers with high fatality rates up to 90% in humans, for which no effective treatment is currently available. The ongoing Ebola outbreak in West Africa that has caused over 14,000 human infections and over 5000 deaths underscores its serious threat to the public health. While licensed vaccines against Ebola virus infection are still not available, a number of vaccine approaches have been developed and shown to protect against lethal Ebola virus infection in animal models. This review aims to summarize the advancement of different strategies for Ebola vaccine development with a focus on the discussion of their protective efficacies and possible limitations. In addition, the development of animal models for efficacy evaluation of Ebola vaccines and the mechanism of immune protection against Ebola virus infection are also discussed. PMID:25526819

Ye, Ling; Yang, Chinglai

2015-02-01

167

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. PMID:19129127

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

2008-01-01

168

Effects of influenza A virus infection on migrating mallard ducks.  

PubMed

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=10918) 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. PMID:19129127

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

2009-03-22

169

Protective effect of an oral infection with Herpes simplex virus type 1 against subsequent genital infection with Herpes simplex virus type 2  

Microsoft Academic Search

The problem of whether oral Herpes simplex virus type 1 (HSV-1) infection provides protection against subsequent genital infection by Herpes simplex virus type 2 (HSV-2) was investigated. Mice were used as models. Following conditions in man, both the oral and genital infections applied were noninjurious. Mice infected orally with HSV-1 were weakly protected against virus ‘take’ following vaginal challenge with

Bernhard Sturn; Karl-Eduard Schneweis

1978-01-01

170

Regulation of transplacental virus infection by developmental and immunological factors: studies with lactate dehydrogenase-elevating virus  

Microsoft Academic Search

Placental and fetal infections with lactate dehydrogenase-elevating virus (LDV) were determined by virus titration, indirect fluorescence antibody (IFA), and in situ hybridization with cDNA probes. Experiments were designed to determine the effects of gestational age, timing of maternal LDV infection, and immunological (antibody and cytokine) factors on mouse placental and fetal LDV infection. Virus infection of the placenta was detected

Thomas R Haven; Raymond R. R Rowland; Peter G. W Plagemann; Grace H. W Wong; Sarahann E Bradley; William A Cafruny

1996-01-01

171

In vitro Enhancement of Respiratory Syncytial Virus Infection of U937 Cells by Human Sera  

Microsoft Academic Search

SUMMARY Human sera containing respiratory syncytial (RS) virus-specific antibodies enhance RS virus infection of the U937 macrophage cell line. There was an increase in the number of cells expressing virus antigen when U937 cells were infected with RS virus in the presence of human serum compared to cells infected in the absence of human serum. Human sera enhanced virus yield,

H. B. Gimenez; H. M. Keir; P. Cash

1989-01-01

172

Herpesvirus simiae (B virus): Replication of the virus and identification of viral polypeptides in infected cells  

Microsoft Academic Search

Summary The events and products of replication ofHerpesvirus simiae (B virus) in Vero cells were studied. The time course of the synthetic events of DNA replication and protein synthesis were found to be similar to the processes of the herpes simplex viruses and SA 8. Infectious progeny virus were detected by 4 hours post infection and were first found extracellularly

J. K. Hilliard; R. Eberle; S. L. Lipper; R. M. Munoz; S. A. Weiss

1987-01-01

173

Virus reactivation in pigs latently infected with a thymidine kinase negative vaccine strain of pseudorabies virus  

Microsoft Academic Search

Summary Attenuated, gene-deletion mutants of pseudorabies virus (PRV) were tested for their ability to establish a reactivatable latent infection in pigs. The viruses (designated A, B, and C) were from each of three vaccines commercially available in the United States. Viruses A and C were similar in that they had genetically engineered gene deletions for thymidine kinase (TK) and glycoprotein

W. L. Mengeling

1991-01-01

174

Influenza Virus A (H1N1) in Giant Anteaters (Myrmecophaga tridactyla)  

PubMed Central

In February 2007, an outbreak of respiratory disease occurred in a group of giant anteaters (Myrmecophaga tridactyla) at the Nashville Zoo. Isolates from 2 affected animals were identified in March 2007 as a type A influenza virus related to human influenza subtype H1N1. PMID:19624924

Nofs, Sally; Abd-Eldaim, Mohamed; Thomas, Kathy V.; Toplon, David; Rouse, Dawn

2009-01-01

175

Influenza virus A (H1N1) in giant anteaters (Myrmecophaga tridactyla).  

PubMed

In February 2007, an outbreak of respiratory disease occurred in a group of giant anteaters (Myrmecophaga tridactyla) at the Nashville Zoo. Isolates from 2 affected animals were identified in March 2007 as a type A influenza virus related to human influenza subtype H1N1. PMID:19624924

Nofs, Sally; Abd-Eldaim, Mohamed; Thomas, Kathy V; Toplon, David; Rouse, Dawn; Kennedy, Melissa

2009-07-01

176

Use of Noninvasive Markers To Detect Leishmania Infection in Asymptomatic Human Immunodeficiency Virus-Infected Patients  

Microsoft Academic Search

Visceral leishmaniasis (VL) caused by Leishmania infantum is a common disease in human immunodefi- ciency virus (HIV)-infected people in the Mediterranean basin. However, most such cases are asymptomatic, and little information about the prevalence of these infections in HIV-infected individuals is available. The aim of this study was to assess the prevalence of subclinical infection and the relationship between several

Angela Camacho; Cristina Riera; Francisco Morillas-Marquez; Salvador Vergara; Juan Macõ ´ as; Juan A. Pineda

2006-01-01

177

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

178

Herpesvirus simiae (B virus): replication of the virus and identification of viral polypeptides in infected cells.  

PubMed

The events and products of replication of Herpesvirus simiae (B virus) in Vero cells were studied. The time course of the synthetic events of DNA replication and protein synthesis were found to be similar to the processes of the herpes simplex viruses and SA 8. Infectious progeny virus were detected by 4 hours post infection and were first found extracellularly between 6 and 8 hours post infection (PI). As in the case of SA 8, all cell lines tested were permissive for lytic infection by B virus. Analyses of B virus-infected cells by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) revealed approximately 50 infected cell polypeptides (ICP) ranging in molecular weight from about 26,000 to 239,000 daltons. The kinetics of synthesis of the ICPs were also identified. At least nine glucosamine-containing glycopeptides were noted ranging from 133,000 to 29,000 daltons. PMID:3030236

Hilliard, J K; Eberle, R; Lipper, S L; Munoz, R M; Weiss, S A

1987-01-01

179

Hepatitis C virus infection in hemodialysis patients.  

PubMed

Hepatitis C virus (HCV) infection is observed in around 20% of dialysis patients and in allograft recipients and results in a significant morbidity and mortality, especially after transplantation. Its prevalence has markedly decreased in patients who are candidates for transplantation since the introduction of screening, hygiene and prevention measures, including systematic screening of blood and organ donations, use of erythropoietin, and compliance with universal hygiene rules. A liver biopsy is preferable to non-invasive biochemical and/or morphological tests of fibrosis to evaluate liver fibrosis before and even after transplantation. In HCV-infected dialyzed patients who are not candidates for renal transplantation, the indication for antiviral therapy is limited to significant fibrosis (fibrosis ? 2 on the METAVIR scale). Antiviral treatment should be proposed to any HCV-infected candidate for renal transplantation, whatever the baseline histopathology. The recommendation is to use standard interferon-? as monotherapy, but pegylated interferon can be used, resulting in sustained virological response, while low doses of combined ribavirin may enhance the antiviral efficacy. After transplantation, interferon-? is contra-indicated but may be used in patients for whom the benefits of antiviral treatment clearly outweigh the risks, especially that of allograft rejection. All cirrhotic patients should be screened for hepatocellular carcinoma, whose risk is enhanced by immunosuppressive regimens. Sustained suppression of necro-inflammation may result in the reversal of cirrhosis, which reduces liver-related morbidity and improves patient and allograft survival. Finally, due to the high mortality after renal transplantation, active cirrhosis must be considered to be a contraindication to kidney transplantation, but an indication to combined liver-kidney transplantation; on the contrary, inactive compensated cirrhosis may permit renal transplantation alone. PMID:23933193

Vallet-Pichard, Anais; Pol, Stanislas

2013-09-01

180

JC Virus Antibody Status Underestimates Infection Rates  

PubMed Central

Background JC virus (JCV) seropositivity is a risk factor for progressive multifocal leukoencephalopathy (PML) in patients on natalizumab. Accordingly, the JCV serological antibody test is of paramount importance in determining disease risk. Methods We tested the accuracy of the JCV serum antibody test by comparing the results of JCV serology to JC viruria and viremia in 67 patients enrolled in a single-center, retrospective cohort study. Bodily fluids (urine and blood) were assessed for JCV DNA by real time quantitative polymerase chain reaction 6 to 47 months earlier (mean 26.1 months) before JCV antibody testing. In 10 individuals, blood and urine samples were obtained on two separate occasions at 6 month intervals. Results Forty (59.7%) of the 67 patients were JCV seropositive. Of 27 JCV seronegative patients, 10 (37%) had JC viruria. Urine JCV DNA copy numbers were significantly higher in the seropositive group (mean log copy number: 5.93; range 1.85 – 9.21) than the seronegative group (mean log copy number: 2.41; range 1.85 – 5.43) (p=0.0026). Considering all body fluid test results, 50 (74.6%) of the 67 patients were previously infected with JCV. Conclusions The false negative rate of the JCV serology in this study was 37%; therefore, JCV serostatus does not appear to identify all patients infected with JCV. Thus, a negative JCV antibody result should not be conflated with absence of JCV infection. This discordance may be important in understanding JCV biology, risk for PML and PML pathogenesis. PMID:23526716

Berger, Joseph R.; Houff, Sidney A.; Gurwell, Julie; Vega, Nubia; Miller, Craig S.; Danaher, Robert J.

2013-01-01

181

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. PMID:24175212

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

2012-01-01

182

Proteolysis of the Ebola Virus Glycoproteins Enhances Virus Binding and Infectivity  

Microsoft Academic Search

Cellular cathepsins are required for Ebola virus infection and are believed to proteolytically process the Ebola virus glycoprotein (GP) during entry. However, the significance of cathepsin cleavage during infection remains unclear. Here we demonstrate a role for cathepsin L (CatL) cleavage of Ebola virus GP in the generation of a stable 18-kDa GP1 viral intermediate that exhibits increased binding to

Rachel L. Kaletsky; Graham Simmons; Paul Bates

2007-01-01

183

Screening for Hepatitis B Virus Infection in Nonpregnant Adolescents and Adults  

MedlinePLUS

Understanding Task Force Recommendations Screening for Hepatitis B Virus Infection in Nonpregnant Adolescents and Adults The U.S. ... B infection? Hepatitis B is one of several viruses that can damage the liver. The virus is ...

184

Detection, pathogenesis, and therapy of respiratory syncytial virus infections.  

PubMed Central

Respiratory syncytial virus (RSV) infection is a major cause of serious lower respiratory disease in infancy and early childhood. The unique pathogenesis of lower respiratory illness due to RSV offers some intriguing clues to the role of the human immune system in both protection against and development of respiratory illness. More than any other virus, rapid diagnostic techniques have been especially successful in identifying RSV infection. Many of these techniques could be easily adaptable to diagnosis of influenza virus infection and other agents. Finally, ribavirin therapy of RSV infection represents one of the few instances in which antiviral therapy has been shown to be effective for respiratory illnesses. Fundamental observations in these areas in the case of RSV infection open up new and exciting pathways for investigation of respiratory infection due to other viral, chlamydial, and mycoplasmal agents. PMID:3060243

Welliver, R C

1988-01-01

185

Experimental infections in man and horses with influenza A viruses*  

PubMed Central

The recognition of an antigenic relationship between the haemagglutinins of A/Equi-2 and A2/Hong Kong/68 viruses led to experimental studies in man and horses with these virus types. Human volunteers were inoculated with A/Equi-2/Miami/63 virus and virus shedding ensued in all subjects. The most common clinical response was a febrile illness indistinguishable from naturally occurring human influenza. After administration of A2/Hong Kong/68 virus to 10 ponies there was virus shedding from 9 and a febrile response in 6. When the human subjects previously inoculated with equine virus were challenged with A2/Hong Kong/68 virus, the frequency of illness and the extent of virus shedding were lower than was observed among control individuals. This immunity was found to be related to the level of heterologous serum antibody to the human virus which developed after equine virus infection. Challenge with A/Equi-2/Miami/63 virus of ponies previously inoculated with A2/Hong Kong/68 virus, in the absence of any measurable levels of heterologous antibody to the human strain, resulted in less shedding of virus among these than occurred in control animals. PMID:5309454

Kasel, J. A.; Couch, R. B.

1969-01-01

186

Occult hepatitis B virus infection in hemodialysis patients in Japan.  

PubMed

Hepatitis B surface antigen is widely used in hepatitis B virus surveillance; patients who test negative for the antigen are judged to be uninfected. However, occult hepatitis B virus infection has been confirmed with hepatitis B virus DNA at low levels in the liver and peripheral blood in patients positive for hepatitis B core antibody or hepatitis B surface antibody, even if they test negative for hepatitis B surface antigen. To investigate the prevalence of occult hepatitis B virus in hemodialysis patients, we performed cross-sectional analysis of 161 hemodialysis patients in two related institutions for hepatitis B surface antigen, hepatitis B core antibody, and hepatitis B surface antibody. Hepatitis B surface antigen, hepatitis B core antibody, or hepatitis B surface antibody was present in 45 patients (28.0%). Hepatitis B virus DNA was present in six patients (3.7%), all of whom also tested positive for hepatitis B core antibody. Hepatitis B surface antibody positivity was unrelated in only one of the six patients. Four of the six patients were positive for hepatitis B surface antigen; however, two (1.3%) of these with occult hepatitis B virus infection were found to be hepatitis B surface antigen negative. Occult hepatitis B virus infection may be missed in hepatitis B virus surveillance using hepatitis B surface antigen alone; therefore, routine hepatitis B core antibody screening is necessary. Patients who test positive for hepatitis B core antibody should undergo further hepatitis B virus DNA testing to enable accurate hepatitis B virus screening. PMID:25363685

Saijo, Tomokatsu; Joki, Nobuhiko; Inishi, Yoji; Muto, Mikako; Saijo, Motohiko; Hase, Hiroki

2015-04-01

187

Phylogenetic analysis of the haemagglutinin gene of canine distemper virus strains detected from giant panda and raccoon dogs in China  

PubMed Central

Background Canine distemper virus (CDV) infects a variety of carnivores, including wild and domestic Canidae. In this study, we sequenced and phylogenetic analyses of the hemagglutinin (H) genes from eight canine distemper virus (CDV) isolates obtained from seven raccoon dogs (Nyctereutes procyonoides) and a giant panda (Ailuropoda melanoleuca) in China. Results Phylogenetic analysis of the partial hemagglutinin gene sequences showed close clustering for geographic lineages, clearly distinct from vaccine strains and other wild-type foreign CDV strains, all the CDV strains were characterized as Asia-1 genotype and were highly similar to each other (91.5-99.8% nt and 94.4-99.8% aa). The giant panda and raccoon dogs all were 549Y on the HA protein in this study, irrespective of the host species. Conclusions These findings enhance our knowledge of the genetic characteristics of Chinese CDV isolates, and may facilitate the development of effective strategies for monitoring and controlling CDV for wild canids and non-cainds in China. PMID:23566727

2013-01-01

188

Borna disease (BD), a slow virus infection biological properties of the virus  

Microsoft Academic Search

Borna disease, a typical slow virus infection, was investigated in different animal species. Infectious virus in the brain and complement-fixing and precipitating antibodies in the circulation could be detected simultaneously several months p.i. The infectious agent was propagated in rabbit brain tissue cultures, which were cocultivated with green monkey kidney cells. Infectious virus and virus-specific antigens were demonstrable in the

H. Ludwig; H. Becht; Lydia Groh

1973-01-01

189

Auxiliary metabolic genes in viruses infecting marine cyanobacteria  

E-print Network

Marine viruses shape the diversity and biogeochemical role of their microbial hosts. Cyanophages that infect the cyanobacteria Prochlorococcus and Synechococcus often carry metabolic genes not found in other bacteriophages. ...

Thompson, Luke Richard

2010-01-01

190

Mammalian cell stress responses during Semliki Forest virus infection   

E-print Network

Virus infection of mammalian cells induces several stress mechanisms, including autophagy and type-I interferon (IFN). Autophagy, a cellular homeostatic mechanism in which intracellular materials are sequestered into ...

Ferguson, Mhairi Catriona

2013-07-06

191

Quantity of dengue virus required to infect rhesus monkeys.  

PubMed

As part of a dengue vaccine study, it was necessary to determine how much virus was required to infect rhesus monkeys. Serial dilutions of dengue 2 and 4 viruses were inoculated subcutaneously into groups of five monkeys and seroconversions determined on days 30 and 60 post-inoculation. The viruses were also titrated simultaneously in LLC-MK2 cells and mosquitoes. It was calculated that 9.5 mosquito infectious doses 50 (MID50) of dengue 2 virus and 22 MID50 of dengue 4 virus were required to infect 50% of the monkeys. The data suggest that 100 MID50 of dengue virus should be used as a challenge dose for monkeys previously immunized with dengue vaccine. PMID:2860743

Kraiselburd, E; Gubler, D J; Kessler, M J

1985-01-01

192

Immune responses of infants to infection with respiratory viruses and live attenuated respiratory virus candidate vaccines.  

PubMed

Respiratory viruses such as respiratory syncytial virus (RSV), the parainfluenza viruses (PIV), and the influenza viruses cause severe lower respiratory tract diseases in infants and children throughout the world. Experimental live attenuated vaccines for each of these viruses are being developed for intranasal administration in the first weeks or months of life. A variety of promising RSV, PIV-3, and influenza virus vaccine strains have been developed by classical biological methods, evaluated extensively in preclinical and clinical studies, and shown to be attenuated and genetically stable. The ongoing clinical evaluation of these vaccine candidates, coupled with recent major advances in the ability to develop genetically engineered viruses with specified mutations, may allow the rapid development of respiratory virus strains that possess ideal levels of replicative capacity and genetic stability in vivo. A major remaining obstacle to successful immunization of infants against respiratory virus associated disease may be the relatively poor immune response of very young infants to primary virus infection. This paper reviews the immune correlates of protection against disease caused by these viruses, immune responses of infants to naturally-acquired infection, and immune responses of infants to experimental infection with candidate vaccine viruses. PMID:9711783

Crowe, J E

1998-01-01

193

The effect of infection with bovine viral diarrhea virus on the fertility of Swiss dairy cattle  

Microsoft Academic Search

Bovine viral diarrhea virus is a major cattle pathogen with a worldwide distribution. Animals may be infected with BVD virus transiently or persistently. Transient infection leads to protective immunity. Persistent infection is unique because it is associated with an immunotolerance that is specific to the infecting strain of BVD virus. Persistent infection results from viral invasion of fetuses between the

J. Rüfenacht; P. Schaller; L. Audigé; B. Knutti; U. Küpfer; E. Peterhans

2001-01-01

194

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

195

Reticular Erythematous Mucinosis Associated with Human Immunodeficiency Virus Infection  

Microsoft Academic Search

We report the case of a 56-year-old woman with reticular erythematous mucinosis (REM). During her workup infection with the human immunodeficiency virus (HIV) was detected. She developed a cerebral toxoplasmosis, salmonella sp. bacteremia and oral ulcerations with the presence of type I herpes simplex virus and cytomegalovirus. The relation of REM with the deposition of mucin in AIDS patients’ bone

E. Daudén; P. F. Peñas; G. F. Buezo; J. Fraga; A. García-Diez

1995-01-01

196

Impact of Simian Immunodeficiency Virus Infection on Chimpanzee Population Dynamics  

Microsoft Academic Search

Like human immunodeficiency virus type 1 (HIV-1), simian immunodeficiency virus of chimpanzees (SIVcpz) can cause CD4+ T cell loss and premature death. Here, we used molecular surveillance tools and mathematical modeling to estimate the impact of SIVcpz infection on chimpanzee population dynamics. Habituated (Mitumba and Kasekela) and non-habituated (Kalande) chimpanzees were studied in Gombe National Park, Tanzania. Ape population sizes

Rebecca S. Rudicell; James Holland Jones; Emily E. Wroblewski; Gerald H. Learn; Yingying Li; Joel D. Robertson; Elizabeth Greengrass; Falk Grossmann; Shadrack Kamenya; Lilian Pintea; Deus C. Mjungu; Elizabeth V. Lonsdorf; Anna Mosser; Clarence Lehman; D. Anthony Collins; Brandon F. Keele; Jane Goodall; Beatrice H. Hahn; Anne E. Pusey; Michael L. Wilson

2010-01-01

197

Effects of influenza A virus infection on migrating mallard ducks  

Microsoft Academic Search

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

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

2009-01-01

198

Tick-Borne Encephalitis Virus Infection of Cultured Mouse Macrophages  

Microsoft Academic Search

The interactions of tick-borne encephalitis virus (TBEV) with mouse macrophages were studied at the electron microscopic level. The cultured mouse macrophages were sensitive to infection with TBEV strain Hypr (a highly neuroinvasive and neurovirulent strain for laboratory mice) and produced relatively high virus titers. However, these macrophage cells remained morphologically inactivated. Viral particles were located mainly in the ER but

Arunee Ahantarig; Marie Vancová; Anna Janowitz; Hana Štastná; Libor Grubhoffer

2009-01-01

199

Effect of chemicals on the infectivity of chicken anaemia virus  

Microsoft Academic Search

None of five commercial disinfectants, invert soap, amphoteric soap, orthodichlorobenzene, iodine disinfectant and sodium hypochlorite, was completely effective in destroying the infectivity of chicken anaemia virus (CAV) in liver material at 5% concentration. However, the iodine disinfectant and sodium hypochlorite completely inactivated the virus in tissue culture (TC) material when used at 1% concentration. CAV was resistant to organic solvents

N. Yuasa

1992-01-01

200

EFFECT OF CHLORINE TREATMENT ON INFECTIVITY OF HEPATITIS A VIRUS  

EPA Science Inventory

This study examined the effect of chlorine treatment on the infectivity of hepatitis A virus (HAV). Prodromal chimpanzee feces, shown to induce hepatitis in marmosets (Saguinus sp.), was clarified, and the virus was precipitated with 7% polyethylene glycol 6000, harvested and res...

201

Outbreak of Severe Zoonotic Vaccinia Virus Infection, Southeastern Brazil  

PubMed Central

In 2010, a vaccinia virus isolate caused an atypically severe outbreak that affected humans and cattle in Brazil. Of 26 rural workers affected, 12 were hospitalized. Our data raise questions about the risk factors related to the increasing number and severity of vaccinia virus infections. PMID:25811411

Abrahão, Jônatas Santos; Campos, Rafael Kroon; Trindade, Giliane de Souza; Guimarães da Fonseca, Flávio; Ferreira, Paulo César Peregrino

2015-01-01

202

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. PMID:22710350

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

2012-01-01

203

Protective efficacy of neutralizing antibodies against Ebola virus infection  

Microsoft Academic Search

Ebola virus causes lethal hemorrhagic fever in humans and nonhuman primates, but no effective antiviral compounds are available for the treatment of this infection. The surface glycoprotein (GP) of Ebola virus is an important target of neutralizing antibodies. Although passive transfer of GP-specific antibodies has been evaluated in mouse and guinea pig models, protection was achieved only by treatment shortly

Ayato Takada; Hideki Ebihara; Steven Jones; Heinz Feldmann; Yoshihiro Kawaoka

2007-01-01

204

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

205

Persistent Infection with Ebola Virus under Conditions of Partial Immunity  

Microsoft Academic Search

Ebola hemorrhagic fever in humans is associated with high mortality; however, some infected hosts clear the virus and recover. The mechanisms by which this occurs and the correlates of protective immunity are not well defined. Using a mouse model, we determined the role of the immune system in clearance of and protection against Ebola virus. All CD8 T-cell-deficient mice succumbed

Manisha Gupta; Siddhartha Mahanty; Patricia Greer; Jonathan S. Towner; Wun-Ju Shieh; Sherif R. Zaki; Rafi Ahmed; Pierre E. Rollin

2004-01-01

206

Whitefly Transmission of a New Virus Infecting Cucurbits in Florida  

Technology Transfer Automated Retrieval System (TEKTRAN)

A virus isolated from squash collected in Hillsborough County, FL in 2003, which was subsequently determined to be an ipomovirus, was transmitted by the silverleaf whitefly, Bemisia tabaci B strain in laboratory experiments. The virus was acquired by whiteflies after a 3-h access period on infected ...

207

In vivo imaging of cidofovir treatment of cowpox virus infection  

Microsoft Academic Search

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)

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

2007-01-01

208

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. PMID:24062733

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

2013-01-01

209

Experimental St. Louis encephalitis virus infection of sloths and cormorants.  

PubMed

Experimental infection of 11 Bradypus variegatus and Choloepus hoffmanni sloths with St. Louis encephalitis (SLE) virus produced detectable viremias of seven to 27 (median 13) days duration and maximum titers of 2.7 to 6.5 (median 5.1) log10 median suckling mouse intracranial lethal doses (SMicLD50) per ml. Experimental SLE viremia onset was delayed and maximum titer depressed in two sloths concurrently infected with naturally acquired viruses. SLE viremias in four experimentally inoculated cormorants Phalacrocorax olivaceus were shorter, and of equal or lower titer, than in sloths. Colonized Culex pipiens quinquefasciatus mosquitoes were infected by feeding on sloths circulating at least 4.8 log10 SMicLD50 of SLE virus per ml, and subsequently transmitted the infection to mice and chicks. An uninoculated baby Bradypus became infected by contact transmission from its mother. The antibody response of sloths to SLE virus was slow, being undetectable until several weeks post-inoculation. However, both sloth species developed high and long-lasting neutralizing and hemagglutination-inhibition antibody titers. The complement-fixation antibody response in Bradypus was lower and slower to develop than in Choloepus. Sloths with naturally acquired SLE virus antibody did not become detectably viremic after experimental inoculation. Neither sloths nor cormorants become overly ill from SLE virus infection. PMID:6881434

Seymour, C; Kramer, L D; Peralta, P H

1983-07-01

210

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

211

The neuropathogenesis of feline immunodeficiency virus infection: Barriers to overcome  

PubMed Central

Feline immunodeficiency virus (FIV), like human immunodeficiency virus (HIV)-1, is a neurotropic lentivirus, and both natural and experimental infections are associated with neuropathology. FIV enters the brain early following experimental infection, most likely via the blood-brain and blood-cerebrospinal fluid barriers. The exact mechanism of entry, and the factors that influence this entry, are not fully understood. As FIV is a recognised model of HIV-1 infection, understanding such mechanisms is important, particularly as HIV enters the brain early in infection. Furthermore, the development of strategies to combat this central nervous system (CNS) infection requires an understanding of the interactions between the virus and the CNS. In this review the results of both in vitro and in vivo FIV studies are assessed in an attempt to elucidate the mechanisms of viral entry into the brain. PMID:20418131

Fletcher, Nicola F.; Meeker, Rick B.; Hudson, Lola C.; Callanan, John J.

2010-01-01

212

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. PMID:24198431

He, Yaodong; Yang, Kai

2014-01-01

213

Reduced Risk of Disease During Postsecondary Dengue Virus Infections  

PubMed Central

Background.?Antibodies induced by infection with any 1 of 4 dengue virus (DENV) serotypes (DENV-1–4) may influence the clinical outcome of subsequent heterologous infections. To quantify potential cross-protective effects, we estimated disease risk as a function of DENV infection, using data from longitudinal studies performed from September 2006 through February 2011 in Iquitos, Peru, during periods of DENV-3 and DENV-4 transmission. Methods.?DENV infections before and during the study period were determined by analysis of serial serum samples with virus neutralization tests. Third and fourth infections were classified as postsecondary infections. Dengue fever cases were detected by door-to-door surveillance for acute febrile illness. Results.?Among susceptible participants, 39% (420/1077) and 53% (1595/2997) seroconverted to DENV-3 and DENV-4, respectively. Disease was detected in 7% of DENV-3 infections and 10% of DENV-4 infections. Disease during postsecondary infections was reduced by 93% for DENV-3 and 64% for DENV-4, compared with primary and secondary infections. Despite lower disease rates, postsecondary infections constituted a significant proportion of apparent infections (14% [for DENV-3 infections], 45% [for DENV-4 infections]). Conclusions.?Preexisting heterotypic antibodies markedly reduced but did not eliminate the risk of disease in this study population. These results improve understanding of how preinfection history can be associated with dengue outcomes and DENV transmission dynamics. PMID:23776195

Olkowski, Sandra; Forshey, Brett M.; Morrison, Amy C.; Rocha, Claudio; Vilcarromero, Stalin; Halsey, Eric S.; Kochel, Tadeusz J.; Scott, Thomas W.; Stoddard, Steven T.

2013-01-01

214

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. PMID:24782642

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

2014-01-01

215

[Cellular mediated immunity in virus infections].  

PubMed

The intervention of cellular immunity in the course of specific antiviral defence is suggested or confirmed by a series of clinical and experimental findings, i.e. the evolution of certain viral diseases following a second contact with viral antigens; discrepancy between the level of antiviral serum antibodies and the clinical course of some viral diseases; pathohistological alterations in some viral diseases, suggesting the intervention of cellular immunity; the clinical aspects of natural or experimental viral diseases in primary and secondary immunodeficiency. Investigations were likewise carried out on certain indices of cellular immunity in human or experimental viral diseases, such as delayed hypersensitivity skin tests; the transfer of immune lymphocytes; lymphocytic blastic transformation; inhibition of macrophage migration; specific cytotoxicity test. The problems concerning the role of cellular immunity in the specific defence against viruses may be grouped as follows: mechanisms of induction of the immune cellular response in viral infections; relationship between cellular and humoral immunity in antiviral resistance; relative independance of systemic and local cellular immunity in the course of viral diseases; the cellular basis of cellular mediated immunity in viral diseases. PMID:353956

Voiculescu, C; T??ulescu, M

1978-01-01

216

Recombinant Vesicular Stomatitis Virus–Based Vaccines Against Ebola and Marburg Virus Infections  

PubMed Central

The filoviruses, Marburg virus and Ebola virus, cause severe hemorrhagic fever with a high mortality rate in humans and nonhuman primates. Among the most-promising filovirus vaccines under development is a system based on recombinant vesicular stomatitis virus (rVSV) that expresses a single filovirus glycoprotein (GP) in place of the VSV glycoprotein (G). Importantly, a single injection of blended rVSV-based filovirus vaccines was shown to completely protect nonhuman primates against Marburg virus and 3 different species of Ebola virus. These rVSV-based vaccines have also shown utility when administered as a postexposure treatment against filovirus infections, and a rVSV-based Ebola virus vaccine was recently used to treat a potential laboratory exposure. Here, we review the history of rVSV-based vaccines and pivotal animal studies showing their utility in combating Ebola and Marburg virus infections. PMID:21987744

Feldmann, Heinz

2011-01-01

217

Natural Intrauterine Infection with Schmallenberg Virus in Malformed Newborn Calves  

PubMed Central

We surveyed morphologic alterations in calves in Belgium that were naturally infected in utero by Schmallenberg virus (SBV) and born with deformities during January–March 2012. SBV-specific RNA was distributed unevenly in different tissues. Natural intrauterine SBV infection of calves might cause serious damage to the central nervous system and muscles. PMID:25062351

Bayrou, Calixte; Garigliany, Mutien-Marie; Sarlet, Michael; Sartelet, Arnaud; Cassart, Dominique

2014-01-01

218

Spectroscopic detection and identification of infected cells with herpes viruses.  

PubMed

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and Fourier transform infrared (FTIR) microspectroscopy were previously applied for the identification of various biological samples. In the present study, normal cells in culture and cells infected with herpes simplex virus type 2 (HSV-2) or varicella-zoster virus (VZV) were analyzed by MALDI-TOF and FTIR microscopy. Specific spectral biomarkers for rapid and reliable monitoring and identification of infected cells and probably for the discrimination between these viruses were searched. The results show consistent spectral peaks in all examined normal uninfected human fibroblast cells both in MALDI-T0F and FTIR microscopy. In HSV-2- or VZV-infected cells, two unique peaks for each appeared at m/z 5397 and 5813 or at m/z 3501 and 4951, respectively, in MALDI-TOF spectra. In addition, several peaks that appeared in control uninfected cells at the region m/z 13,000-20,000 disappeared completely in all examined infected samples. When these infected cells were examined by FTIR microscopy, a band at 859 cm(-1) in control uninfected cells was significantly shifted to 854 cm(-1) in both HSV2- and VZV-infected cells. In addition, phosphate levels were considerably increased in all infected cells compared to normal uninfected cells. These parameters could be used as a basis for developing a spectral method for the detection and identification of cells infected with herpes viruses. PMID:18932269

Erukhimovitch, Vitaly; Karpasasa, Mark; Huleihel, Mahmoud

2009-01-01

219

Heart and Skeletal Muscle Are Targets of Dengue Virus Infection  

PubMed Central

Background Dengue fever is one of the most significant re-emerging tropical diseases, despite our expanding knowledge of the disease, viral tropism is still not known to target heart tissues or muscle. Methods A prospective pediatric clinical cohort of 102 dengue hemorrhagic fever patients from Colombia, South America, was followed for 1 year. Clinical diagnosis of myocarditis was routinely performed. Electrocardiograph and echocardiograph analysis were performed to confirm those cases. Immunohistochemistry for detection of dengue virus and inflammatory markers was performed on autopsied heart tissue. In vitro studies of human striated skeletal fibers (myotubes) infected with dengue virus were used as a model for myocyte infection. Measurements of intracellular Ca2+ concentration as well as immunodetection of dengue virus and inflammation markers in infected myotubes were performed. Results Eleven children with dengue hemorrhagic fever presented with symptoms of myocarditis. Widespread viral infection of the heart, myocardial endothelium, and cardiomyocytes, accompanied by inflammation was observed in 1 fatal case. Immunofluorescence confocal microscopy showed that myotubes were infected by dengue virus and had increased expression of the inflammatory genes and protein IP-10. The infected myotubes also had increases in intracellular Ca2+ concentration. Conclusions Vigorous infection of heart tissues in vivo and striated skeletal cells in vitro are demonstrated. Derangements of Ca2+ storage in the infected cells may directly contribute to the presentation of myocarditis in pediatric patients. PMID:20032806

Salgado, Doris Martha; Eltit, José Miguel; Mansfield, Keith; Panqueba, César; Castro, Dolly; Vega, Martha Rocio; Xhaja, Kris; Schmidt, Diane; Martin, Katherine J.; Allen, Paul D.; Rodriguez, Jairo Antonio; Dinsmore, Jonathan H.; López, José Rafael; Bosch, Irene

2010-01-01

220

Antibody landscapes after influenza virus infection or vaccination  

E-print Network

to study immune profiles covering 43 years of influenza A/H3N2 virus evolution for 69 individuals monitored for infection over six years and for 225 individuals pre- and post-vaccination. On infection and vaccination titers increased broadly, including...

Fonville, J. M.; Wilks, S. H.; James, S. L.; Fox, A.; Ventresca, M.; Aban, M.; Xue, L.; Jones, T. C.; Le, N. M. H.; Pham, Q. T.; Tran, N. D.; Wong, Y.; Mosterin, A.; Katzelnick, L. C.; Labonte, D.; Le, T. T.; van der Net, G.; Skepner, E.; Russell, C. A.; Kaplan, T. D.; Rimmelzwaan, G. F.; Masurel, N.; de Jong, J. C.; Palache, A.; Beyer, W. E. P.; Le, Q. M.; Nguyen, T. H.; Wertheim, H. F. L.; Hurt, A. C.; Osterhaus, A. D. M. E.; Barr, I. G.; Fouchier, R. A. M.; Horby, P. W.; Smith, D. J.

2014-01-01

221

Kinetics of Influenza A Virus Infection in Humans  

Microsoft Academic Search

Currently, little is known about the viral kinetics of influenza A during infection within an individual. We utilize a series of mathematical models of increasing complexity, which incorporate target cell limitation and the innate interferon response, to examine influenza A virus kinetics in the upper respiratory tracts of experimentally infected adults. The models were fit to data from an experimental

Prasith Baccam; Catherine Beauchemin; Catherine A. Macken; Frederick G. Hayden; Alan S. Perelson

2006-01-01

222

Host Transcription Profiles upon Primary Respiratory Syncytial Virus Infection  

Microsoft Academic Search

Respiratory syncytial virus (RSV) is a common cause of severe lower respiratory tract infection in children. Severe RSV disease is related to an inappropriate immune response to RSV resulting in enhanced lung pathology which is influenced by host genetic factors. To gain insight into the early pathways of the patho- genesis of and immune response to RSV infection, we determined

Riny Janssen; Jeroen Pennings; Hennie Hodemaekers; Annemarie Buisman; Marijke van Oosten; Lia de Rond; Kemal Ozturk; Jan Dormans; Tjeerd Kimman; Barbara Hoebee

2007-01-01

223

Eastern Equine Encephalomyelitis Virus Infection in a Horse from California  

Microsoft Academic Search

A yearling quarter horse, which was raised in southern California, received routine vaccinations for pre- vention of infection by Eastern equine encephalomyelitis virus (EEEV). One week later, severe neurologic signs developed, and the horse was humanely destroyed. A vaccine-related encephalomyelitis was later suspected. A final diagnosis of EEEV infection was established on the basis of acute onset of the neuro-

Robert P. Franklin; Hailu Kinde; Michele T. Jay; Laura D. Kramer; Emily-Gene N. Green; Robert E. Chiles; Eileen Ostlund; Stan Husted; Jonathan Smith; Michael D. Parker

2002-01-01

224

The role of antibody in enhancing dengue virus infection.  

PubMed

Dengue virus has four distinct serotypes whose cross-reactive immune responses contribute to increased disease severity following heterologous infections. It was proposed that non-protective cross-reactive antibodies may play a role in disease enhancement. In this study we develop a mathematical model of host-virus interaction and predict the mechanisms responsible for virus expansion and loss during primary and secondary dengue infections. We use the model to determine the role of cross-reactive antibodies during dengue fever and dengue hemorrhagic fever-inducing secondary infections, and then compare the model to published patient data. We predict that the cross-reactive antibodies interfere with the non-neutralizing antibody effects by reducing the phagocyte-mediated removal of antibody-virus immune complexes. PMID:25707916

Nikin-Beers, Ryan; Ciupe, Stanca M

2015-05-01

225

Clinical aspects of feline immunodeficiency and feline leukemia virus infection.  

PubMed

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses with a global impact on the health of domestic cats. The two viruses differ in their potential to cause disease. FIV can cause an acquired immunodeficiency syndrome that increases the risk of developing opportunistic infections, neurological diseases, and tumors. In most naturally infected cats, however, FIV itself does not cause severe clinical signs, and FIV-infected cats may live many years without any health problems. FeLV is more pathogenic, and was long considered to be responsible for more clinical syndromes than any other agent in cats. FeLV can cause tumors (mainly lymphoma), bone marrow suppression syndromes (mainly anemia) and lead to secondary infectious diseases caused by suppressive effects of the virus on bone marrow and the immune system. Today, FeLV is less important as a deadly infectious agent as in the last 20 years prevalence has been decreasing in most countries. PMID:21807418

Hartmann, Katrin

2011-10-15

226

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

227

Sheep persistently infected with Border disease readily transmit virus to calves seronegative to BVD virus.  

PubMed

Bovine viral diarrhea- and Border disease viruses of sheep belong to the highly diverse genus pestivirus of the Flaviviridae. Ruminant pestiviruses may infect a wide range of domestic and wild cloven-hooved mammals (artiodactyla). Due to its economic importance, programs to eradicate bovine viral diarrhea are a high priority in the cattle industry. By contrast, Border disease is not a target of eradication, although the Border disease virus is known to be capable of also infecting cattle. In this work, we compared single dose experimental inoculation of calves with Border disease virus with co-mingling of calves with sheep persistently infected with this virus. As indicated by seroconversion, infection was achieved only in one out of seven calves with a dose of Border disease virus that was previously shown to be successful in calves inoculated with BVD virus. By contrast, all calves kept together with persistently infected sheep readily became infected with Border disease virus. The ease of viral transmission from sheep to cattle and the antigenic similarity of bovine and ovine pestiviruses may become a problem for demonstrating freedom of BVD by serology in the cattle population. PMID:24315041

Braun, U; Reichle, S F; Reichert, C; Hässig, M; Stalder, H P; Bachofen, C; Peterhans, E

2014-01-10

228

Experimental Everglades Virus Infection of Cotton Rats (Sigmodon hispidus)  

PubMed Central

Everglades virus (EVEV), an alphavirus in the Venezuelan equine encephalitis (VEE) serocomplex, circulates among rodents and vector mosquitoes and infects humans, causing a febrile disease sometimes accompanied by neurologic manifestations. EVEV circulates near metropolitan Miami, which indicates the potential for substantial human disease, should outbreaks arise. We characterized EVEV infection of cotton rats in South Florida, USA, to validate their role in enzootic transmission. To evaluate whether the viremia induced in cotton rat populations regulates EVEV distribution, we also infected rats from a non–EVEV-endemic area. Viremia levels developed in rats from both localities that exceeded the threshold for infection of the vector. Most animals survived infection with no signs of illness, despite virus invasion of the brain and the development of mild encephalitis. Understanding the mechanisms by which EVEV-infected cotton rats resist clinical disease may be useful in developing VEE therapeutics for equines and humans. PMID:15663857

Coffey, Lark L.; Carrara, Anne-Sophie; Paessler, Slobodan; Haynie, Michelle L.; Bradley, Robert D.; Tesh, Robert B.

2004-01-01

229

Persistent erythema multiforme associated with Epstein-Barr virus infection.  

PubMed

Erythema multiforme (EM) is a common, self-limiting condition. Recurrent EM is a well-recognised variant, often associated with herpes simplex virus infection. It is frequently managed with prophylactic aciclovir. Anecdotal reports suggest that recurrent EM may be associated with the use of corticosteroids. Persistent EM, however, is a rare variant, with few cases reported in the literature. It has a protracted course often with atypical and inflammatory lesions. It has been associated with occult viral infections, particularly Epstein-Barr Virus (EBV), as well as inflammatory bowel disease and malignancy. We report a case of EM associated with EBV infection. PMID:24313260

Turnbull, N; Hawkins, D; Atkins, M; Francis, N; Roberts, N

2014-03-01

230

Systemic granulomatous arteritis associated with Epstein-Barr virus infection  

Microsoft Academic Search

A 61-year-old woman initially presented with symptoms and findings reminiscent of infectious mononucleosis, and her illness\\u000a then took a rapidly fatal course. Autopsy revealed widespread granulomatous arteritis, with multinucleated giant cells but\\u000a without eosinophils and fibrinoid necrosis, affecting small arteries and arterioles and infiltration of haemophagocytic histiocytes\\u000a into many organs. In situ hybridization with Epstein-Barr virus (EBV)-specific oligonucleotide probes showed

S. Ban; Yoshiya Goto; Kouichi Kamada; Motohide Takahama; Hiroshi Watanabe; Taiki Iwahori; Hiroaki Takeuchi

1999-01-01

231

Live Bivalent Vaccine for Parainfluenza and Influenza Virus Infections  

PubMed Central

Influenza and human parainfluenza virus infections are of both medical and economical importance. Currently, inactivated vaccines provide suboptimal protection against influenza, and vaccines for human parainfluenza virus infection are not available, underscoring the need for new vaccines against these respiratory diseases. Furthermore, to reduce the burden of vaccination, the development of multivalent vaccines is highly desirable. Thus, to devise a single vaccine that would elicit immune responses against both influenza and parainfluenza viruses, we used reverse genetics to generate an influenza A virus that possesses the coding region for the hemagglutinin/neuraminidase ectodomain of parainfluenza virus instead of the influenza virus neuraminidase. The recombinant virus grew efficiently in eggs but was attenuated in mice. When intranasally immunized with the recombinant vaccine, all mice developed antibodies against both influenza and parainfluenza viruses and survived an otherwise lethal challenge with either of these viruses. This live bivalent vaccine has obvious advantages over combination vaccines, and its method of generation could, in principle, be applied in the development of a “cocktail” vaccine with efficacy against several different infectious diseases. PMID:15890905

Maeda, Yasuko; Hatta, Masato; Takada, Ayato; Watanabe, Tokiko; Goto, Hideo; Neumann, Gabriele; Kawaoka, Yoshihiro

2005-01-01

232

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

233

Neuropathogenesis of Simian Immunodeficiency Virus infection in macaque monkeys  

Microsoft Academic Search

Patients infected with human immunodeficiency virus (HIV) develop immunologic dysfunction and multiorgan inflammatory diseases directly associated with HIV-1 infection. Of these inflammatory diseases, the most devastating to the HIV-infected patient is involvement of the central nervous system (CNS). The pathogenesis of the clinical syndrome observed in these patients, termed HIV-associated dementia, remains poorly understood. However, as most of the detectable

Vito G Sasseville; Andrew A Lackner

1997-01-01

234

Demography and presentation of chronic hepatitis B virus infection.  

PubMed

Currently, >350 million people worldwide are affected by chronic infection with the hepatitis B virus (HBV). Chronic infection may cause cirrhosis and hepatocellular carcinoma; HBV infection is responsible for 328,000 cancer deaths per year. In areas of high HBV endemicity, most infections occur early in life; infected children do not mount an effective immune response and exhibit immune tolerance, so that the risk of chronic infection is high. In areas of low endemicity, infections tend to be in adults within defined risk groups, and the risk of chronicity is much lower. Population migration from areas of high endemicity to areas of low endemicity is creating pockets of HBV infection in areas of low general prevalence, necessitating improved efforts to screen, vaccinate, and treat. Chronic HBV infection is a complicated, nonlinear disease with a variable course of progression; predictors of progression include the duration of time in the immunoactive phase of disease that follows the immune tolerant phase when hepatocytes are attacked. Additionally, the duration of a high viremic state, with ongoing clinical hepatitis and possibly concurrent infections (e.g., hepatitis C, human immunodeficiency virus), influence outcome. Targeted vaccination of high-risk groups has many limitations. Universal childhood vaccination to prevent chronic infection and its sequelae is the only approach that will lead to the global elimination of chronic HBV infection. PMID:19185072

Heathcote, E Jenny

2008-12-01

235

In vitro infection of primary and retrovirus-infected human leukocytes by human foamy virus.  

PubMed Central

The infectivity of human foamy virus (HFV) was examined in primary and cultured human leukocytes. Cell-free infectious viral stocks of HFV were prepared from the human kidney cell line 293 transfected with an infectious molecular clone of HFV. HFV productively infects a variety of human myeloid and lymphoid cell lines. In addition, primary cell cultures enriched for human CD4+, monocytes and brain-derived microglial cells, were readily infected by HFV. Interestingly, while infected primary CD4+ lymphocytes and microglial cells showed marked cytopathology characteristic of foamy virus, HFV-infected monocyte-derived macrophages failed to show any cytopathology. In addition, marked cytotoxicity due to HFV infection was seen in both human T-cell leukemia virus type 1- and human immunodeficiency virus type 1-infected T-cell lines and in human immunodeficiency virus type 1-infected monocytoid cell lines. Thus, HFV infection produces differential cytopathology in a wide host range of primary human leukocytes and hematopoietic cell lines. PMID:8627751

Mikovits, J A; Hoffman, P M; Rethwilm, A; Ruscetti, F W

1996-01-01

236

Neuromuscular Manifestations of West Nile Virus Infection  

PubMed Central

The most common neuromuscular manifestation of West Nile virus (WNV) infection is a poliomyelitis syndrome with asymmetric paralysis variably involving one (monoparesis) to four limbs (quadriparesis), with or without brainstem involvement and respiratory failure. This syndrome of acute flaccid paralysis may occur without overt fever or meningoencephalitis. Although involvement of anterior horn cells in the spinal cord and motor neurons in the brainstem are the major sites of pathology responsible for neuromuscular signs, inflammation also may involve skeletal or cardiac muscle (myositis, myocarditis), motor axons (polyradiculitis), and peripheral nerves [Guillain–Barré syndrome (GBS), brachial plexopathy]. In addition, involvement of spinal sympathetic neurons and ganglia provides an explanation for autonomic instability seen in some patients. Many patients also experience prolonged subjective generalized weakness and disabling fatigue. Despite recent evidence that WNV may persist long-term in the central nervous system or periphery in animals, the evidence in humans is controversial. WNV persistence would be of great concern in immunosuppressed patients or in those with prolonged or recurrent symptoms. Support for the contention that WNV can lead to autoimmune disease arises from reports of patients presenting with various neuromuscular diseases that presumably involve autoimmune mechanisms (GBS, other demyelinating neuropathies, myasthenia gravis, brachial plexopathies, stiff-person syndrome, and delayed or recurrent symptoms). Although there is no specific treatment or vaccine currently approved in humans, and the standard remains supportive care, drugs that can alter the cascade of immunobiochemical events leading to neuronal death may be potentially useful (high-dose corticosteroids, interferon preparations, and intravenous immune globulin containing WNV-specific antibodies). Human experience with these agents seems promising based on anecdotal reports. PMID:22461779

Leis, A. Arturo; Stokic, Dobrivoje S.

2012-01-01

237

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. PMID:24918921

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

2014-01-01

238

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

239

Neuraminidase inhibitors for influenza B virus infection: efficacy and resistance  

PubMed Central

Many aspects of the biology and epidemiology of influenza B viruses are far less studied than for influenza A viruses, and one of these aspects is effectiveness and resistance to the clinically available antiviral drugs, the neuraminidase (NA) inhibitors (NAIs). Acute respiratory infections are one of the leading causes of death in children and adults, and influenza is among the few respiratory infections that can be prevented and treated by vaccination and antiviral treatment. Recent data has suggested that influenza B virus infections are of specific concern to pediatric patients because of the increased risk of severe disease. Treatment of influenza B is a challenging task for the following reasons: NAIs (e.g., oseltamivir and zanamivir) are the only FDA-approved class of antivirals available for treatment;the data suggest that oseltamivir is less effective than zanamivir in pediatric patients;zanamivir is not prescribed to patients younger than 7;influenza B viruses are less susceptible than influenza A viruses to NAIs in vitro;although the level of resistance to NAIs is low, the number of different molecular markers of resistance is higher than for influenza A viruses, and they are not well defined;the relationship between levels of NAI phenotypic resistance and known molecular markers, frequency of emergence, transmissibility, and fitness of NAI-resistant variants are not well established. This review presents current knowledge of the effectiveness of NAIs for influenza B virus and antiviral resistance in clinical, surveillance, and experimental studies. PMID:24013000

Burnham, Andrew J.; Baranovich, Tatiana; Govorkova, Elena A.

2013-01-01

240

Dissecting the Role of COPI Complexes in Influenza Virus Infection  

PubMed Central

As an obligate pathogen, influenza virus requires host cell factors and compartments to mediate productive infection and to produce infectious progeny virus. Recently, several small interfering RNA (siRNA) knockdown screens revealed influenza virus host dependency proteins, all of which identified at least two subunits of the coat protein I (COPI) complex. COPI proteins oligomerize to form coated vesicles that transport contents between the Golgi apparatus and the endoplasmic reticulum, and they have also been reported to mediate endosomal trafficking. However, it remains unclear which steps in the influenza virus infection cycle rely on the COPI complex. Upon systematic dissection of the influenza virus infection cycle, from entry to progeny virion production, we found that prolonged exposure to COPI complex disruption through siRNA depletion resulted in significant defects in virus internalization and trafficking to late endosomes. Acute inhibition of COPI complex recruitment to the Golgi apparatus with pharmacological compounds failed to recapitulate the same entry defects as observed with the COPI-depleted cells but did result in specific decreases in viral membrane protein expression and assembly, leading to defects in progeny virion production. Taken together, our findings suggest that COPI complexes likely function indirectly in influenza virus entry but play direct roles in viral membrane protein expression and assembly. PMID:23255804

Sun, Eileen; He, Jiang

2013-01-01

241

Mouse models of hepatitis B and delta virus infection.  

PubMed

Liver disease associated to persistent infection with the hepatitis B virus (HBV) continues to be a major health problem of global impact. Therapeutic regimens currently available can efficiently suppress HBV replication; however, the unique replication strategies employed by HBV permit the virus to persist within the infected hepatocytes. As a consequence, relapse of viral activity is commonly observed after cessation of treatment with polymerase inhibitors. Among the HBV chronically infected patients, more than 15million patients are estimated to be co-infected with the hepatitis delta virus (HDV), a defective satellite virus that needs the HBV envelope for propagation. No specific drugs are currently available against HDV, while nucleos(t)ide analogs are not effective against HDV replication. Since chronic HBV/HDV co-infection leads to the most severe form of chronic viral hepatitis in men, a better understanding of the molecular mechanisms of HDV-mediated pathogenesis and the development of improved therapeutic approaches is urgently needed. The obvious limitations imposed by the use of great apes and the paucity of robust experimental models of HBV infection have hindered progresses in understanding the complex network of virus-host interactions that are established in the course of HBV and HDV infections. This review focuses on summarizing recent advances obtained with well-established and more innovative experimental mouse models, giving emphasis on the strength of infection systems based on the reconstitution of the murine liver with human hepatocytes, as tools for elucidating the whole life cycle of HBV and HDV, as well as for studies on interactions with the infected human hepatocytes and for preclinical drug evaluation. PMID:24631647

Dandri, Maura; Lütgehetmann, Marc

2014-08-01

242

Latent Epstein-Barr virus infection in cottontop tamarins. A possible model for Epstein-Barr virus infection in humans.  

PubMed Central

The association of Epstein-Barr virus (EBV) with a growing number of human malignancies underlines the importance of efforts aimed at preventing the infection with this potential carcinogen and of establishing animal models for human virus-associated tumors. Cottontop tamarins have been used in EBV vaccine studies because virus infection regularly induces lymphomas similar to those seen in human immunocompromised individuals. In recent years, several vaccines based on the gp340/220 envelope protein of EBV have been developed and shown to prevent the development of EBV-associated lymphomas in this model. Using in situ hybridization and immunohistology, we have characterized EBV infection in one nonimmunized and three immunized animals after challenge with a standard tumorigenic dose of EBV. In the nonimmunized animal, EBV-infected lymphoid cells were detected in numerous tissues showing no obvious lymphoma infiltration. Surprisingly, variable numbers of virus-carrying cells were also found in all three immunized animals that were protected against the development of virus-associated lymphoma. This observation demonstrates that vaccination does not induce sterilizing immunity against EBV infection in this model. Double labeling suggested a B cell phenotype of the majority of these cells. EBV infection of nonlymphoid cells was not observed. Analysis of viral gene expression in immunized animals suggested a restricted form of virus latency different from that seen in EBV-driven lymphomas in nonimmunized cottontop tamarins. These results raise the possibility that immunized cottontop tamarins protected against the development of EBV-driven lymphoma or animals exposed to a sublymphomagenic dose of virus may serve as a model for EBV infection in humans. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:7943186

Niedobitek, G.; Agathanggelou, A.; Finerty, S.; Tierney, R.; Watkins, P.; Jones, E. L.; Morgan, A.; Young, L. S.; Rooney, N.

1994-01-01

243

Cholesterol is required for infection by Semliki Forest virus  

PubMed Central

Semliki Forest virus (SFV) and many other enveloped animal viruses enter cells by a membrane fusion reaction triggered by the low pH within the endocytic pathway. In vitro, SFV fusion requires cholesterol in the target membrane, but the role of cholesterol in vivo is unknown. In this paper, the infection pathway of SFV was studied in mammalian and inset cells substantially depleted of sterol. Cholesterol-depleted cells were unaltered in their ability to bind, internalize, and acidify virus, but were blocked in SFV fusion and subsequent virus replication. Depleted cells could be infected by the cholesterol-independent vesicular stomatitis virus, which also enters cells via endocytosis and low pH-mediated fusion. The block in SFV infection was specifically reversed by cholesterol but not by cholestenone, which lacks the critical 3 beta-hydroxyl group. Cholesterol thus is central in the infection pathway of SFV, and may act in vivo to modulate infection by SFV and other pathogens. PMID:1671572

1991-01-01

244

SLAM expression is not downregulated by measles virus infection.  

PubMed

It has been reported that the signaling lymphocyte-activation molecule (SLAM), the second receptor of Measles virus (MV) on the cell surface appears to be downregulated by MV infection or by expression of MV hemagglutinin (H) (Tanaka et al., 2002; Welsteadt et al., 2004). The aim of this study was to analyze this phenomenon in more detail using a Chinese vaccine strain (S191) of MV. Flow cytometry confirmed apparent downregulation of SLAM in the virus-infected cells and in the cells transfected with a plasmid expressing viral H. Moreover, a similar effect was obtained by incubation of the cells with UV-inactivated virus or soluble viral H. Real-time quantitative PCR showed that the SLAM mRNA level remained stable during the virus infection, and Western blot analysis demonstrated that the SLAM content of total membrane proteins did not change change after the virus infection. Thus we conclude that SLAM expression is stable during the MV infection and that its apparent downregulation reported earlier and confirmed also in this study was just the result of masking of the antibody recognition sites on SLAM with MV H during the flow cytometry assay. PMID:17177608

Xu, H; Xu, Q; Zhang, P; Yan, F; Qi, Y

2006-01-01

245

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

246

CHARACTERIZATION OF THREE NOVEL VIRUSES INFECTING RASPBERRY  

Technology Transfer Automated Retrieval System (TEKTRAN)

During routine graft indexing at HCRL (Corvallis, Oregon, a ‘Glen Clova’ plant that originated in Europe induced severe symptoms in indicator plants, causing mottling, epinasty and apical necrosis. Testing for all Rubus viruses with available detection tests failed to identify a known virus in the p...

247

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

248

Eastern Equine Encephalomyelitis Virus Infection in a Horse from California  

PubMed Central

A yearling quarter horse, which was raised in southern California, received routine vaccinations for prevention of infection by Eastern equine encephalomyelitis virus (EEEV). One week later, severe neurologic signs developed, and the horse was humanely destroyed because vaccine-related encephalomyelitis was suspected. A final diagnosis of EEEV infection was established on the basis of acute onset of the neurologic signs, histopathologic and serologic testing, and isolation and molecular characterization of EEEV from brain tissue. The vaccine was extensively tested for viral inactivation. Nucleotide sequences from the vaccine and the virus isolated in the affected horse were also compared. In California, arboviral encephalomyelitides are rarely reported, and EEEV infection has not previously been documented. This report describes the occurrence of EEEV infection in the horse and the investigation to determine the source of infection, which was not definitively identified. PMID:11927026

Kinde, Hailu; Jay, Michele T.; Kramer, Laura D.; Green, Emily-Gene N.; Chiles, Robert E.; Ostlund, Eileen; Husted, Stan; Smith, Jonathan; Parker, Michael D.

2002-01-01

249

Detection of bovine immunodeficiency-like virus infection in experimentally infected calves  

Microsoft Academic Search

Summary.  ?Detection of BIV virus infection by serological means, PCR and virus isolation in experimentally infected calves is described.\\u000a Viral sequences were specifically detected by PCR in peripheral blood mononuclear cells (PBMCs), with primer systems located\\u000a in the gag, pol and tat regions of the viral genome. An enzyme-linked oligosorbent assay (ELOSA) in microtiter plates is described, for the detection\\u000a of

T. Baron; D. Betemps; F. Mallet; V. Cheynet; D. Levy; P. Belli

1998-01-01

250

78 FR 63218 - Draft Guidance for Industry on Chronic Hepatitis C Virus Infection: Developing Direct-Acting...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Guidance for Industry on Chronic Hepatitis C Virus Infection: Developing Direct-Acting...industry entitled ``Chronic Hepatitis C Virus Infection: Developing Direct-Acting...industry entitled ``Chronic Hepatitis C Virus Infection: Developing...

2013-10-23

251

Viral transcription during Autographa californica nuclear polyhedrosis virus infection  

SciTech Connect

The purpose of this research has been to study the transcription process during nuclear polyhedrosis virus infection of S. frugiperda cells. The challenge raised at the beginning of the project was to find the RNA polymerases(s) responsible for the viral RNA synthesis. The results reported here provide the probable answer to this question. It was found that the early viral RNA, being alpha-amanitin sensitive, was transcribed by the host RNA polymerase II. However, the switch later in infection implied an amanitin-resistant viral transcription, as shown in the RNA-DNA hybridization experiments between viral DNA and (/sup 3/H)-RNA synthesized in nuclei isolated from infected cells. A major breakthrough came with the purification of RNA polymerases from infected cells. The DEAE-Sephadex profile showed a distinct peak of alpha-amanitin resistant RNA polymerase activity, which was not present in the DEAE-Sephadex RNA polymerase profile of uninfected cells. This novel activity was, therefore, induced by the nuclear polyhedrosis virus infection. RNA polymerases were isolated from both normal and infected cells. The virus-induced polymerase was characterized and its properties were compared to those of the host RNA polymerase. The results obtained so far suggest that the virus-induced RNA polymerase may be the enzyme responsible for the transcription of the viral late genes.

Fuchs, L.Y.

1985-01-01

252

The influence of virus infections on the course of COPD  

PubMed Central

Chronic obstructive pulmonary disease (COPD) is extensively influenced by viral infections. The mechanisms of how viral agents affect the pathogenesis and prognosis of COPD are numerous. In general, patients with infectious exacerbations are characterized by longer hospitalization periods and greater impairment of several lung function parameters than those with non-infectious exacerbations. Prodromal, clinical, and outcome parameters fail to distinguish virally from non-virally induced illnesses in cases of exacerbations. The importance of infections with respiratory and non-respiratory viral agents for pathogenesis and course of COPD is detailed. Human adenovirus, non-respiratory viruses including human immunodeficiency virus, human metapneumovirus, influenza virus, human rhinovirus, and respiratory syncytial virus are especially stressed. PMID:24688763

Frickmann, H.; Jungblut, S.; Hirche, T. O.; Groß, U.; Kuhns, M.; Zautner, A. E.

2012-01-01

253

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

254

Occult hepatitis B virus infection among Mexican human immunodeficiency virus-1-infected patients  

PubMed Central

AIM: To determine the frequency of occult hepatitis B infection (OHBI) in a group of human immunodeficiency virus (HIV)-1+/ hepatitis B surface antigen negative (HBsAg)- patients from Mexico. METHODS: We investigated the presence of OHBI in 49 HIV-1+/HBsAg- patients. Hepatitis B virus (HBV) DNA was analyzed using nested PCR to amplify the Core (C) region and by real-time PCR to amplify a region of the S and X genes. The possible associations between the variables and OHBI were investigated using Pearson’s ?2 and/or Fisher’s exact test. RESULTS: We found that the frequency of OHBI was 49% among the group of 49 HIV-1+/HBsAg- patients studied. The presence of OHBI was significantly associated with the HIV-1 RNA viral load [odds ratio (OR) = 8.75; P = 0.001; 95%CI: 2.26-33.79] and with HIV-antiretroviral treatment with drugs that interfere with HBV replication (lamivudine, tenofovir or emtricitabine) (OR = 0.25; P = 0.05; 95%CI: 0.08-1.05). CONCLUSION: The OHBI frequency is high among 49 Mexican HIV-1+/HBsAg- patients and it was more frequent in patients with detectable HIV RNA, and less frequent in patients who are undergoing HIV-ARV treatment with drugs active against HBV. PMID:25309083

Alvarez-Muñoz, Ma Teresa; Maldonado-Rodriguez, Angelica; Rojas-Montes, Othon; Torres-Ibarra, Rocio; Gutierrez-Escolano, Fernanda; Vazquez-Rosales, Guillermo; Gomez, Alejandro; Muñoz, Onofre; Torres, Javier; Lira, Rosalia

2014-01-01

255

Cohabitation reaction-diffusion model for virus focal infections  

NASA Astrophysics Data System (ADS)

The propagation of virus infection fronts has been typically modeled using a set of classical (noncohabitation) reaction-diffusion equations for interacting species. However, for some single-species systems it has been recently shown that noncohabitation reaction-diffusion equations may lead to unrealistic descriptions. We argue that previous virus infection models also have this limitation, because they assume that a virion can simultaneously reproduce inside a cell and diffuse away from it. For this reason, we build a several-species cohabitation model that does not have this limitation. Furthermore, we perform a sensitivity analysis for the most relevant parameters of the model, and we compare the predicted infection speed with observed data for two different strains of the T7 virus.

Amor, Daniel R.; Fort, Joaquim

2014-12-01

256

A review on JC virus infection in kidney transplant recipients.  

PubMed

The polyomavirus (PyV), JC virus (JCV), is a small nonenveloped DNA virus that asymptomatically infects about 80% of healthy adults and establishes latency in the kidney tissue. In case of immunodeficient hosts, JCV can lytically infect the oligodendrocytes, causing a fatal demyelinating disease, known as progressive multifocal leukoencephalopathy (PML). Although the reactivation of another human PyV, BK virus (BKV), is relatively common and its association with the polyomavirus associated nephropathy (PyVAN) following renal transplantation is proven, JCV replication and its impact on graft function and survival are less well studied. Here we describe the biology of JCV and its pathological features and we review the literature regarding the JCV infection analyzed in the setting of transplantations. PMID:23424601

Delbue, Serena; Ferraresso, Mariano; Ghio, Luciana; Carloni, Camilla; Carluccio, Silvia; Belingheri, Mirco; Edefonti, Alberto; Ferrante, Pasquale

2013-01-01

257

The first imported case infected with chikungunya virus in Korea.  

PubMed

Chikungunya is caused by an arbovirus transmitted by Aedes mosquito vector. With the increase of habitat of mosquito by global warming and frequent international travel and interchange, chikungunya reemerged and showed global distribution recently. Until now there has not been reported any case infected with chikungunya virus in Korea. A 23-year-old man has been the Republic of the Philippines for 1 week, and visited our emergency center due to fever and back pain. Chikungunya viral infection was diagnosed by specific IgM for chickungunya virus by enzyme-linked immunosorbent assayin Korea Centers for Disease Control and Prevention. His clinical course was self limited. We introduce the first imported case infected with chikungunya virus in Korea. PMID:25844264

Hwang, Jeong-Hwan; Lee, Chang-Seop

2015-03-01

258

BK virus infection: an update on diagnosis and treatment.  

PubMed

BK virus, first isolated in 1971, is a significant risk factor for renal transplant dysfunction and allograft loss. Unfortunately, treatment options for BK virus infection are limited, and there is no effective prophylaxis. Although overimmunosuppression remains the primary risk factor for BK infection after transplantation, male gender, older recipient age, prior rejection episodes, degree of human leukocyte antigen mismatching, prolonged cold ischemia time, BK serostatus and ureteral stent placement have all been implicated as risk factors. Routine screening for BK has been shown to be effective in preventing allograft loss in patients with BK viruria or viremia. Reduction of immunosuppression remains the mainstay of BK nephropathy treatment and is the best studied intervention. Laboratory-based methods such as ELISPOT assays have provided new insights into the immune response to BK and may help guide therapy in the future. In this review, we will discuss the epidemiology of BK virus infection, screening strategies, treatment options and future research directions. PMID:24574543

Sawinski, Deirdre; Goral, Simin

2015-02-01

259

The First Imported Case Infected with Chikungunya Virus in Korea  

PubMed Central

Chikungunya is caused by an arbovirus transmitted by Aedes mosquito vector. With the increase of habitat of mosquito by global warming and frequent international travel and interchange, chikungunya reemerged and showed global distribution recently. Until now there has not been reported any case infected with chikungunya virus in Korea. A 23-year-old man has been the Republic of the Philippines for 1 week, and visited our emergency center due to fever and back pain. Chikungunya viral infection was diagnosed by specific IgM for chickungunya virus by enzyme-linked immunosorbent assayin Korea Centers for Disease Control and Prevention. His clinical course was self limited. We introduce the first imported case infected with chikungunya virus in Korea.

2015-01-01

260

Human immunodeficiency viruses: SIV infection in wild gorillas  

Microsoft Academic Search

Chimpanzees (Pan troglodytes troglodytes) from west central Africa are recognized as the reservoir of simian immunodeficiency viruses (SIVcpzPtt) that have crossed at least twice to humans: this resulted in the AIDS pandemic (from human immunodeficiency virus HIV-1 group M) in one instance and infection of just a few individuals in Cameroon (by HIV-1 group N) in another. A third HIV-1

Fran van Heuverswyn; Yingying Li; Cecile Neel; Elizabeth Bailes; Brandon F. Keele; Weimin Liu; Severin Loul; Christelle Butel; Florian Liegeois; Yanga Bienvenue; Eitel Mpoudi Ngolle; Paul M. Sharp; George M. Shaw; Eric Delaporte; Beatrice H. Hahn; Martine Peeters

2006-01-01

261

Host Cell Cathepsins Potentiate Moloney Murine Leukemia Virus Infection  

Microsoft Academic Search

The roles of cellular proteases in Moloney murine leukemia virus (MLV) infection were investigated using MLV particles pseudotyped with vesicular stomatitis virus (VSV) G glycoprotein as a control for effects on core MLV particles versus effects specific to Moloney MLV envelope protein (Env). The broad-spectrum inhibitors cathepsin inhibitor III and E-64d gave comparable dose-dependent inhibition of Moloney MLV Env and

Pankaj Kumar; Deepa Nachagari; Carolyn Fields; John Franks; Lorraine M. Albritton

2007-01-01

262

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

263

First Isolation of a Giant Virus from Wild Hirudo medicinalis Leech: Mimiviridae isolation in Hirudo medicinalis  

PubMed Central

Giant viruses and amoebae are common in freshwater, where they can coexist with other living multicellular organisms. We screened leeches from the species Hirudo medicinalis for giant viruses. We analyzed five H. medicinalis obtained from Tunisia (3) and France (2). The leeches were decontaminated and then dissected to remove internal parts for co-culture with Acanthamoeba polyphaga. The genomes of isolated viruses were sequenced on a 454 Roche instrument, and a comparative genomics analysis was performed. One Mimivirus was isolated and the strain was named Hirudovirus. The genome assembly generated two scaffolds, which were 1,155,382 and 25,660 base pairs in length. Functional annotations were identified for 47% of the genes, which corresponds to 466 proteins. The presence of Mimividae in the same ecological niche as wild Hirudo may explain the presence of the mimivirus in the digestive tract of the leech, and several studies have already shown that viruses can persist in the digestive tracts of leeches fed contaminated blood. As leeches can be used medically and Mimiviruses have the potential to be an infectious agent in humans, patients treated with leeches should be surveyed to investigate a possible connection. PMID:24287596

Boughalmi, Mondher; Pagnier, Isabelle; Aherfi, Sarah; Colson, Philippe; Raoult, Didier; La Scola, Bernard

2013-01-01

264

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

265

Antiviral Treatment of Chronic Hepatitis B Virus (HBV) Infections  

PubMed Central

While 25 compounds have been formally licensed for the treatment of HIV infection (AIDS), only seven licensed products are currently available for the treatment of chronic hepatitis B virus (HBV) infection: interferon-?, pegylated interferon-?, lamivudine, adefovir (dipivoxil), entecavir, telbivudine and tenofovir (disoproxil fumarate). In contrast to the treatment of HIV infections where the individual drugs are routinely used in combination, for the treatment of chronic HBV infection the individual drugs are generally used in monotherapy. In principle, combination drug therapy should allow reducing the likelihood of drug-resistant development. PMID:21994680

De Clercq, Erik; Férir, Geoffrey; Kaptein, Suzanne; Neyts, Johan

2010-01-01

266

Pathogenesis of Modoc virus (Flaviviridae; Flavivirus) in persistently infected hamsters.  

PubMed

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. PMID:23358636

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

2013-03-01

267

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. PMID:23358636

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

2013-01-01

268

Influenza A virus infection complicated by fatal myocarditis.  

PubMed

Influenza virus typically causes a febrile respiratory illness, but it can present with a variety of other clinical manifestations. We report a fatal case of myocarditis associated with influenza A infection. A previously healthy 11-year-old girl had malaise and fever for approximately 1 week before a sudden, witnessed fatal collapse at home. Autopsy revealed a pericardial effusion, a mixed lymphocytic and neutrophilic myocarditis, a mild lymphocytic interstitial pneumonia, focal bronchial/bronchiolar mucosal necrosis, and histologic changes consistent with asthma. Infection with influenza A (H3N2) was confirmed by virus isolation from a postmortem nasopharyngeal swab. Attempts to isolate virus from heart and lung tissue were unsuccessful. Immunohistochemical tests directed against influenza A antigens and in situ hybridization for influenza A genetic material demonstrated positive staining in bronchial epithelial cells, whereas heart sections were negative. Sudden death is a rare complication of influenza and may be caused by myocarditis. Forensic pathologists should be aware that postmortem nasopharyngeal swabs for viral culture and immunohistochemical or in situ hybridization procedures on lung tissue might be necessary to achieve a diagnosis. Because neither culturable virus nor influenza viral antigen could be identified in heart tissue, the pathogenesis of influenza myocarditis in this case is unlikely to be the result of direct infection of myocardium by the virus. The risk factors for developing myocarditis during an influenza infection are unknown. PMID:11111801

Nolte, K B; Alakija, P; Oty, G; Shaw, M W; Subbarao, K; Guarner, J; Shieh, W J; Dawson, J E; Morken, T; Cox, N J; Zaki, S R

2000-12-01

269

Extrahepatic manifestations of chronic hepatitis C virus infection.  

PubMed

Hepatitis C virus (HCV) infected patients are known to be at risk of developing liver complications i.e. cirrhosis and liver cancer. However, the risks of morbidity and mortality are underestimated because they do not take into account non-liver consequences of chronic hepatitis C virus infection. Numerous extrahepatic manifestations have been reported in up to 74% of patients, from perceived to disabling conditions. The majority of data concern hepatitis C virus-related autoimmune and/or lymphoproliferative disorders, from mixed cryoglobulinaemia vasculitis to frank lymphomas. More recently, other hepatitis C virus-associated disorders have been reported including cardiovascular, renal, metabolic, and central nervous system diseases. This review aims to outline most of the extrahepatic manifestations that are currently being investigated, including some of autoimmune and/or lymphoproliferative nature, and others in which the role of immune mechanisms appears less clear. Beyond the liver, hepatitis C virus chronic infection should be analyzed as a multifaceted systemic disease leading to heavy direct and indirect costs. The accurate consideration of extrahepatic consequences of such a systemic infection significantly increases the weight of its pathological burden. The need for effective viral eradication measures is underlined. PMID:25458776

Cacoub, Patrice; Gragnani, Laura; Comarmond, Cloe; Zignego, Anna Linda

2014-12-15

270

Infection of influenza virus neuraminidase-vaccinated mice with homologous influenza virus leads to strong protection against heterologous influenza viruses.  

PubMed

Vaccination is the best measure to prevent influenza pandemics. Here, we studied the protective effect against heterologous influenza viruses, including A/reassortant/NYMC X-179A (pH1N1), A/Chicken/Henan/12/2004 (H5N1), A/Chicken/Jiangsu/7/2002 (H9N2) and A/Guizhou/54/89×A/PR/8/34 (A/Guizhou-X) (H3N2), in mice first vaccinated with a DNA vaccine of haemagglutinin (HA) or neuraminidase (NA) of A/PR/8/34 (PR8) and then infected with the homologous virus. We showed that PR8 HA or NA vaccination both protected mice against a lethal dose of the homologous virus; PR8 HA or NA DNA vaccination and then PR8 infection in mice offered poor or excellent protection, respectively, against a second, heterologous influenza virus challenge. In addition, before the second heterologous influenza infection, the highest antibody level against nucleoprotein (NP) and matrix (M1 and M2) proteins was found in the PR8 NA-vaccinated and PR8-infected group. The level of induced cellular immunity against NP and M1 showed a trend consistent with that seen in antibody levels. However, PR8 HA+NA vaccination and then PR8 infection resulted in limited protection against heterologous influenza virus challenge. Results of the present study demonstrated that infection of the homologous influenza virus in mice already immunized with a NA vaccine could provide excellent protection against subsequent infection of a heterologous influenza virus. These findings suggested that NA, a major antigen of influenza virus, could be an important candidate antigen for universal influenza vaccines. PMID:25170051

He, Biao; Chang, Haiyan; Liu, Zhihua; Huang, Chaoyang; Liu, Xueying; Zheng, Dan; Fang, Fang; Sun, Bing; Chen, Ze

2014-12-01

271

Detection and diagnosis of rice-infecting viruses  

PubMed Central

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

272

First study of different insect cells to triatoma virus infection.  

PubMed

The use of viruses for biological control is a new option to be considered. The family Dicistroviridae, which affects only invertebrates, is one of the families that have been proposed for this purpose. The Triatoma virus (TrV), a member of this family, affects triatomine transmitters of Chagas disease, which is endemic in Latin America but also expanding its worldwide distribution. To this end, we attempted virus replication in Diptera, Aedes albopictus (clone C6/36) and Lepidoptera Spodoptera frugiperda (SF9, SF21) and High Five (H5) cell lines. The methodologies used were transfection process, direct inoculation (purified virus), and inoculation of purified virus with trypsin. Results were confirmed by SDS-PAGE, Western blotting, RT-PCR, electron microscopy, and immunofluorescence. According to the results obtained, further analysis of susceptibility/infection of H5 cells to TrV required to be studied. PMID:25481388

Susevich, María Laura; Marti, Gerardo Aníbal; Metz, Germán Ernesto; Echeverría, María Gabriela

2015-04-01

273

Reticular erythematous mucinosis associated with human immunodeficiency virus infection.  

PubMed

We report the case of a 56-year-old woman with reticular erythematous mucinosis (REM). During her workup infection with the human immunodeficiency virus (HIV) was detected. She developed a cerebral toxoplasmosis, salmonella sp. bacteremia and oral ulcerations with the presence of type I herpes simplex virus and cytomegalovirus. The relation of REM with the deposition of mucin in AIDS patients' bone marrow and HIV infection is discussed. To our knowledge, this is the first report where REM is associated with HIV disease. PMID:8520066

Daudén, E; Peñas, P F; Buezo, G F; Fraga, J; García-Diez, A

1995-01-01

274

Multiphasic acute disseminated encephalomyelitis associated with atypical rubella virus infection.  

PubMed

We report the first case of an occurrence of multiphasic acute disseminated encephalomyelitis (ADEM) associated with atypical rubella virus infection with no rash and long-term increased titers of serum anti-rubella IgM in a 17-year-old male who had no history of rubella vaccination. He suffered from at least six clinical exacerbations with disseminated hyperintense lesions on FLAIR MR images during the course of 18 months. Repeated methylprednisolone pulse therapy and intravenous immunoglobulin therapy resolved the exacerbations. In patients with multiphasic ADEM of unknown etiology, clinicians should also consider the possibility of preceding infection with rubella virus. PMID:24852921

Shinoda, Koji; Asahara, Hideaki; Uehara, Taira; Miyoshi, Katsue; Suzuki, Satoshi O; Iwaki, Toru; Kira, Jun-ichi

2015-02-01

275

Role of Phosphatidylserine Receptors in Enveloped Virus Infection  

PubMed Central

ABSTRACT We recently demonstrated that a soluble protein, Gas6, can facilitate viral entry by bridging viral envelope phosphatidylserine to Axl, a receptor tyrosine kinase expressed on target cells. The interaction between phosphatidylserine, Gas6, and Axl was originally shown to be a molecular mechanism through which phagocytes recognize phosphatidylserine exposed on dead cells. Since our initial report, several groups have confirmed that Axl/Gas6, as well as other phosphatidylserine receptors, facilitate entry of dengue, West Nile, and Ebola viruses. Virus binding by viral envelope phosphatidylserine is now a viral entry mechanism generalized to many families of viruses. In addition to Axl/Gas6, various molecules are known to recognize phosphatidylserine; however, the effects of these molecules on virus binding and entry have not been comprehensively evaluated and compared. In this study, we examined most of the known human phosphatidylserine-recognizing molecules, including MFG-E8, TIM-1, -3, and -4, CD300a, BAI1, and stabilin-1 and -2, for their abilities to facilitate virus binding and infection. Using pseudotyped lentiviral vectors, we found that a soluble phosphatidylserine-binding protein, MFG-E8, enhances transduction. Cell surface receptors TIM-1 and -4 also enhance virus binding/transduction. The extent of enhancement by these molecules varies, depending on the type of pseudotyping envelope proteins. Mutated MFG-E8, which binds viral envelope phosphatidylserine without bridging virus to cells, but, surprisingly, not annexin V, which has been used to block phagocytosis of dead cells by concealing phosphatidylserine, efficiently blocks these phosphatidylserine-dependent viral entry mechanisms. These results provide insight into understanding the role of viral envelope phosphatidylserine in viral infection. IMPORTANCE Envelope phosphatidylserine has previously been shown to be important for replication of various envelope viruses, but details of this mechanism(s) were unclear. We were the first to report that a bifunctional serum protein, Gas6, bridges envelope phosphatidylserine to a cell surface receptor, Axl. Recent studies demonstrated that many envelope viruses, including vaccinia, dengue, West Nile, and Ebola viruses, utilize Axl/Gas6 to facilitate their entry, suggesting that the phosphatidylserine-mediated viral entry mechanism can be shared by various enveloped viruses. In addition to Axl/Gas6, various molecules are known to recognize phosphatidylserine; however, the effects of these molecules on virus binding and entry have not been comprehensively evaluated and compared. In this study, we examined most human phosphatidylserine-recognizing molecules for their abilities to facilitate viral infection. The results provide insights into the role(s) of envelope phosphatidylserine in viral infection, which can be applicable to the development of novel antiviral reagents that block phosphatidylserine-mediated viral entry. PMID:24478428

Chen, Irvin S. Y.

2014-01-01

276

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. PMID:23283946

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

2013-01-01

277

Experimental rabies virus infection of big brown bats (Eptesicus fuscus).  

PubMed

A captive colony of adult Big Brown Bats (Eptesicus fuscus) was experimentally infected with a rabies virus (RABV) variant isolated from the salivary glands of a naturally infected Big Brown Bat and passaged once through murine neuroblastoma cell culture. Bats were divided into 11 groups, which were composed of one to three noninfected and one to three infected individuals each. Twenty of 38 animals were infected intramuscularly into both left and right masseter muscles; they received a total of 10(3.2) median mouse intracerebral lethal dose (MICLD50) of Big Brown Bat RABV variant. Experimental outcome after viral exposure was followed in the bats for 140 days postinoculation (PI). Of 20 infected bats, 16 developed clinical rabies, and the mean incubation period was 24 days (range: 13-52 days). Three infected bats never seroconverted and succumbed early to infection (13 days). Four infected bats that survived until the end of the experiment without any signs of disease maintained detectable antibody titers until the third month PI, peaking between days 13 and 43, and consequent drop-off below the threshold for detection occurred by day 140. Limited excretion of virus in saliva of infected bats during the clinical course of disease was observed in two individuals on days 13 and 15 PI (<24 hr prior to onset of clinical illness). No bat-to-bat transmission of RABV to noninfected bats was detected. PMID:18689646

Jackson, Felix R; Turmelle, Amy S; Farino, David M; Franka, Richard; McCracken, Gary F; Rupprecht, Charles E

2008-07-01

278

Natural History of Primary Epstein-Barr Virus Infection in Children of Mothers Infected with Human Immunodeficiency Virus Type 1  

PubMed Central

The natural history of Epstein-Barr virus (EBV) infection in 556 infants born to 517 human immunodeficiency virus (HIV) type 1–infected mothers was studied in a prospective, multicenter, cohort study. HIV-1–infected children had a cumulative EBV infection rate similar to HIV-1–uninfected children at age 3 years (77.8% vs. 84.9%) but had more frequent oropharyngeal EBV shedding (50.4% vs. 28.2%; P < .001). The probability of shedding decreased with longer time from EBV seroconversion and was similar to that of HIV-1–uninfected children 3 years after seroconversion. HIV-1–infected children identified as rapid progressors shed EBV more frequently than nonrapid progressors (69.4% vs.41.0%; P = .01). HIV-1–infected children with EBV infection had higher mean CD8 cell counts. EBV infection did not have an independent effect on mean CD4 cell counts, percent CD4, IgG levels, HIV-1 RNA levels, lymphadenopathy, hepatomegaly, or splenomegaly. Early EBV infection is common in children born to HIV-1–infected mothers. Children with rapidly progressive HIV-1 disease have more frequent EBV shedding. PMID:10228060

Jenson, Hal; McIntosh, Kenneth; Pitt, Jane; Husak, Scott; Tan, Ming; Bryson, Yvonne; Easley, Kirk

2015-01-01

279

A single vertebrate DNA virus protein disarms invertebrate immunity to RNA virus infection  

PubMed Central

Virus-host interactions drive a remarkable diversity of immune responses and countermeasures. We found that two RNA viruses with broad host ranges, vesicular stomatitis virus (VSV) and Sindbis virus (SINV), are completely restricted in their replication after entry into Lepidopteran cells. This restriction is overcome when cells are co-infected with vaccinia virus (VACV), a vertebrate DNA virus. Using RNAi screening, we show that Lepidopteran RNAi, Nuclear Factor-?B, and ubiquitin-proteasome pathways restrict RNA virus infection. Surprisingly, a highly conserved, uncharacterized VACV protein, A51R, can partially overcome this virus restriction. We show that A51R is also critical for VACV replication in vertebrate cells and for pathogenesis in mice. Interestingly, A51R colocalizes with, and stabilizes, host microtubules and also associates with ubiquitin. We show that A51R promotes viral protein stability, possibly by preventing ubiquitin-dependent targeting of viral proteins for destruction. Importantly, our studies reveal exciting new opportunities to study virus-host interactions in experimentally-tractable Lepidopteran systems. DOI: http://dx.doi.org/10.7554/eLife.02910.001 PMID:24966209

Gammon, Don B; Duraffour, Sophie; Rozelle, Daniel K; Hehnly, Heidi; Sharma, Rita; Sparks, Michael E; West, Cara C; Chen, Ying; Moresco, James J; Andrei, Graciela; Connor, John H; Conte, Darryl; Gundersen-Rindal, Dawn E; Marshall, William L; Yates, John R; Silverman, Neal; Mello, Craig C

2014-01-01

280

Antigen-Specific Expansion of Cytotoxic T Lymphocytes in Acute Measles Virus Infection  

Microsoft Academic Search

Skewing of the T-cell receptor repertoire of CD81 T cells has been shown in some persistent infections with viruses, such as human immunodeficiency virus, simian immunodeficiency virus, and Epstein-Barr virus. We have demonstrated that similar distortions also occur in nonpersistent measles virus infection. In addition, two of four children immunized with live, attenuated measles virus showed larger and more persistent

JUTHATHIP MONGKOLSAPAYA; ASSAN JAYE; MARGARET F. C. CALLAN; ALBERT F. MAGNUSEN; ANDREW J. MCMICHAEL

1999-01-01

281

Experimental infection of vertebrates of the Pocomoke Cypress Swamp, Maryland with Keystone and Jamestown Canyon viruses.  

PubMed

Experimental studies were conducted to assess the susceptibility of white-tailed deer (Odocoileus virginianus), gray squirrels (Sciurus carolinensis), and cottontail rabbits (Sylvilagus floridanus) to Jamestown Canyon (JC) and/or Keystone (KEY) virus infection. Viremia occurred in 5 of 6 deer inoculated with JC virus; however, all deer developed KEY virus neutralizing antibody. Based on the observation that antibody elicited by primary infection of deer with either KEY or JC virus exhibited partial heterologous neutralization in vitro, cross-challenge experiments were performed in these animals. Keystone virus failed to infect deer 30 days post primary JC virus infection; however, deer became infected when challenged with KEY virus 80 days after the initial JC virus infection as indicated by a substantial increase in antibody titer. Similarly, JC virus failed to produce viremia in immune animals infected with KEY virus 80 days previously, although 2 of the 3 animals challenged had serological evidence of infection. Three field-collected cottontail rabbits with no evidence of KEY antibody were readily susceptible to KEY virus infection and developed viremias of 1-4 days' duration; rabbits with KEY virus antibody did not develop viremia upon KEY virus challenge. Eight antibody-negative field-collected gray squirrels became viremic following injection with KEY virus; however, a comparable group of squirrels did not become viremic when injected with JC virus. PMID:453437

Watts, D M; Tammariello, R F; Dalrymple, J M; Eldridge, B F; Russell, P K; Top, F H

1979-03-01

282

Host Neutralizing Responses in Hepatitis C Virus Infection Mirjam B. Zeisel1, 2  

E-print Network

Host Neutralizing Responses in Hepatitis C Virus Infection Mirjam B. Zeisel1, 2 , Samira Fafi. Key words: hepatitis C virus; virus-host cell interaction; viral entry; neutralizing antibodies 1;Abstract Hepatitis C virus (HCV) is a major cause of hepatitis world-wide. The majority of infected

Boyer, Edmond

283

Flow cytometric monitoring of influenza A virus infection in MDCK cells during vaccine production  

Microsoft Academic Search

BACKGROUND: In cell culture-based influenza vaccine production the monitoring of virus titres and cell physiology during infection is of great importance for process characterisation and optimisation. While conventional virus quantification methods give only virus titres in the culture broth, data obtained by fluorescence labelling of intracellular virus proteins provide additional information on infection dynamics. Flow cytometry represents a valuable tool

Josef Schulze-Horsel; Yvonne Genzel; Udo Reichl

2008-01-01

284

Antiviral responses of human Leydig cells to mumps virus infection or poly I:C stimulation  

E-print Network

of viruses in the human testis and hence the harmful intrusion of acquired immune cells, and how some virusesAntiviral responses of human Leydig cells to mumps virus infection or poly I:C stimulation A. Le was to test whether mumps virus infection of isolated human Leydig cells was associated with an inhibition

Paris-Sud XI, Université de

285

Hepatitis B and human immunodeficiency virus co-infection  

PubMed Central

Hepatitis B and human immunodeficiency virus (HBV and HIV) infection share transmission patterns and risk factors, which explains high prevalence of chronic HBV infection in HIV infected patients. The natural course of HBV disease is altered by the HIV infection with less chance to clear acute HBV infection, faster progression to cirrhosis and higher risk of liver-related death in HIV-HBV co-infected patients than in HBV mono-infected ones. HIV infected patients with chronic hepatitis B should be counseled for liver damage and surveillance of chronic hepatitis B should be performed to screen early hepatocellular carcinoma. Noninvasive tools are now available to evaluate liver fibrosis. Isolated hepatitis B core antibodies (anti-HBc) are a good predictive marker of occult HBV infection. Still the prevalence and significance of occult HBV infection is controversial, but its screening may be important in the management of antiretroviral therapy. Vaccination against HBV infection is recommended in non-immune HIV patients. The optimal treatment for almost all HIV-HBV co-infected patients should contain tenofovir plus lamivudine or emtricitabine and treatment should not be stopped to avoid HBV reactivation. Long term tenofovir therapy may lead to significant decline in hepatitis B surface Antigen. The emergence of resistant HBV strains may compromise the HBV therapy and vaccine therapy. PMID:25516647

Phung, Bao-Chau; Sogni, Philippe; Launay, Odile

2014-01-01

286

PRRSV receptors and their roles in virus infection.  

PubMed

Porcine reproductive and respiratory syndrome virus (PRRSV) has a restricted cell tropism and prefers to invade well-differentiated cells of the monocyte/macrophage lineage, such as pulmonary alveolar macrophages and African green monkey kidney cell line MA-104 and its derivatives, such as Marc-145, Vero and CL-2621. PRRSV infection of the host cells actually is a receptor-mediated endocytosis and replication process. The presence and absence of the cellular receptors decide whether the cell lines are permissive or non-permissive to PRRSV infection. Several PRRSV non-permissive cell lines, such as BHK-21, PK-15 and CHO-K1, have been shown to become sensitive to the virus infection upon expression of the recombinant receptor proteins. Up to now, heparin sulfate, sialoadhesin, CD163, CD151 and vimentin have been identified as the important PRRSV receptors via their involvement in virus attachment, internalization or uncoating. Each receptor is characterized by the distribution in different cells, the function in virus different infection stages and the interaction model with the viral proteins or genes. Joint forces of the receptors recently attract attentions due to the specific function. PRRSV receptors have become the targets for designing the new anti-viral reagents or the recombinant cell lines used for isolating the viruses or developing more effective vaccines due to their more conserved sequences compared with the genetic variation of the virus. In this paper, the role of PRRSV receptors and the molecular mechanism of the interaction between the virus and the receptors are reviewed. PMID:25666932

Shi, Chongxu; Liu, Yali; Ding, Yaozhong; Zhang, Yongguang; Zhang, Jie

2015-05-01

287

Drug targets in infections with Ebola and Marburg viruses.  

PubMed

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, we examine the current treatments available to administer care for filovirus infection, the potential therapeutic targets that can be used for filovirus drug development, and the various drug targeting techniques used against filoviruses. PMID:19275706

Gene, Olinger G; Julia, Biggins E; Vanessa, Melanson R; Victoria, Wahl-Jensen; Thomas, Geisbert W; Lisa, Hensley E

2009-04-01

288

Urinary Tract Infections in Male Veterans With Human Immunodeficiency Virus  

PubMed Central

Treatment duration for men with urinary tract infection (UTI) and human immunodeficiency virus (HIV) infection is unknown. Fiscal year 2009 Veterans Affairs administrative data were used to compare men with HIV and UTI with non-HIV men with UTI. Antimicrobial selection and duration were similar. Shorter treatment (?7 days) did not affect recurrence, suggesting that treatment beyond 7 days may be unnecessary. PMID:25734168

Eccles-Radtke, Caitlin; Rector, Thomas S.; Cutting, Andrea; Drekonja, Dimitri M.

2014-01-01

289

Neuromuscular complications of human immunodeficiency virus infection and antiretroviral therapy.  

PubMed Central

At least 4 distinct peripheral neuropathy syndromes occur in patients infected with the human immunodeficiency virus. The most common, painful sensory neuropathy, may be related to the viral infection or may be medication induced and is treated symptomatically. The other 3, chronic inflammatory demyelinating polyradiculoneuropathy, mononeuropathy multiplex (some patients), and the progressive polyradiculopathies related to the acquired immunodeficiency syndrome, may all respond to appropriate therapy. Both inflammatory myopathy and zidovudine myopathy also abate with early diagnosis and treatment. PMID:8048229

Miller, R G

1994-01-01

290

Risk factors for hepatitis C virus infection among homeless adults  

Microsoft Academic Search

OBJECTIVE: To describe the prevalence of hepatitis C virus (HCV) infection in a sample of homeless and impoverished adults and examine\\u000a risk factors for HCV infection in the overall sample and as a function of injection drug use.\\u000a \\u000a \\u000a DESIGN: Assays were conducted on stored sera. Socio-demographic characteristics and risky sexual activity were measured by content-specific\\u000a items. Substance use was measured

Adeline M. Nyamathi; Elizabeth L. Dixon; Wendie Robbins; Cynthia Smith; Dorothy Wiley; Barbara Leake; Douglas Longshore; Lillian Gelberg

2002-01-01

291

STUDIES OF ARTHROPOD-BORNE VIRUS INFECTIONS IN QUEENSLAND  

Microsoft Academic Search

The group-reactive haemagglutination-inhibition (HI) test applied to sera collected from children and sentinel fowls detected a series of infections with group B arboviruses in the Carpentaria-Cape York Peninsula area between 1957 and 1961. The more specific neutralization test suggested that the infecting viruses included kunjin (several centres in 1958–1959), Kokobera (Mapoon, 1957–1959) and Murray Valley encephalitis (MVE) (Mitchell River, 1960),

RL Doherty; JG Carley; BM Gorman; Patricia Buchanan; JS Welch; RH Whitehead

1964-01-01

292

The Role of IKK? in Venezuelan Equine Encephalitis Virus Infection  

PubMed Central

Venezuelan equine encephalitis virus (VEEV) belongs to the genus Alphavirus, family Togaviridae. VEEV infection is characterized by extensive inflammation and studies from other laboratories implicated an involvement of the NF-?B cascade in the in vivo pathology. Initial studies indicated that at early time points of VEEV infection, the NF-?B complex was activated in cells infected with the TC-83 strain of VEEV. One upstream kinase that contributes to the phosphorylation of p65 is the IKK? component of the IKK complex. Our previous studies with Rift valley fever virus, which exhibited early activation of the NF-?B cascade in infected cells, had indicated that the IKK? component underwent macromolecular reorganization to form a novel low molecular weight form unique to infected cells. This prompted us to investigate if the IKK complex undergoes a comparable macromolecular reorganization in VEEV infection. Size-fractionated VEEV infected cell extracts indicated a macromolecular reorganization of IKK? in VEEV infected cells that resulted in formation of lower molecular weight complexes. Well-documented inhibitors of IKK? function, BAY-11-7082, BAY-11-7085 and IKK2 compound IV, were employed to determine whether IKK? function was required for the production of infectious progeny virus. A decrease in infectious viral particles and viral RNA copies was observed with inhibitor treatment in the attenuated and virulent strains of VEEV infection. In order to further validate the requirement of IKK? for VEEV replication, we over-expressed IKK? in cells and observed an increase in viral titers. In contrast, studies carried out using IKK??/? cells demonstrated a decrease in VEEV replication. In vivo studies demonstrated that inhibitor treatment of TC-83 infected mice increased their survival. Finally, proteomics studies have revealed that IKK? may interact with the viral protein nsP3. In conclusion, our studies have revealed that the host IKK? protein may be critically involved in VEEV replication. PMID:24586253

Amaya, Moushimi; Voss, Kelsey; Sampey, Gavin; Senina, Svetlana; de la Fuente, Cynthia; Mueller, Claudius; Calvert, Valerie; Kehn-Hall, Kylene; Carpenter, Calvin; Kashanchi, Fatah; Bailey, Charles; Mogelsvang, Soren; Petricoin, Emanuel; Narayanan, Aarthi

2014-01-01

293

Giant Thyroid Abscess Related to Postpartum Brucella Infection  

PubMed Central

Thyroid gland infection, although rare, may be a life threatening disease. Thyroid abscess, arising from acute suppurative thyroiditis (AST), is a rare clinic condition depending on widespread use of antibiotics. Infection may involve one or both lobes and abscess formation may not be apparent until late stage of the progress of illness. Thyroid left lobe is more often affected than the right one. Brucellosis, especially obvious in endemic areas, is a widely seen zoonosis around the world. Although brucella infection can affect many organs through various complications, thyroid gland infection is rare. We aimed to present ultrasonography (USG) and magnetic resonance images (MRI) of a case with an acute thyroiditis which rapidly developed and grew fast on the left half of the neck during the first postpartum month. As far as we know from literature reviewing, our case is the first case report of a thyroid abscess arising from brucella infection which is developed in first postpartum period with images of ultrasonography and MRI. PMID:25861492

Akdemir, Zülküf; Karaman, Erbil; Akdeniz, Hüseyin; Alptekin, Cem

2015-01-01

294

AN INFECTIVITY ASSAY FOR THE BOVINE LEUKEMIA VIRUS BASED ON THE INDUCTION OF THE MAJOR  

E-print Network

AN INFECTIVITY ASSAY FOR THE BOVINE LEUKEMIA VIRUS BASED ON THE INDUCTION OF THE MAJOR INTERNAL leukemia virus (BLV) as well as BLV-infected lymphocytes induce rapid syncytia formation in several cell the basis of several infectivity assays for leukemia viruses (Woods et al., 1970 ; Sarma et a/.,1971

Paris-Sud XI, Université de

295

Hepatitis B virus treatment in HIV-infected patients.  

PubMed

Hepatitis B virus (HBV) infection is common in HIV-infected persons and is associated with increased risk of liver-related morbidity and mortality. Agents available to treat HBV infection in coinfected patients include lamivudine, entecavir, emtricitabine, adefovir, peginterferon alfa, and the recently approved telbivudine. Treatment decisions should take into account a number of factors, including antiretroviral therapy status, HBV genotype, prior experience of lamivudine, and the need to avoid drug resistance in both HIV- and HBV-infected persons. This article summarizes a presentation on treatment and management of HBV infection in HIV-infected patients made by Chloe L. Thio, MD, at the 9th Annual Ryan White CARE Act Update in Washington, DC. The original presentation is available as a Webcast at www.iasusa.org. PMID:17237559

Thio, Chloe L

296

Broadly neutralizing antibodies abrogate established hepatitis C virus infection  

PubMed Central

Hepatitis C virus (HCV) establishes a chronic infection in the majority of exposed individuals and can cause cirrhosis and hepatocellular carcinoma. The role of antibodies directed against HCV in disease progression is poorly understood. Neutralizing antibodies (nAbs) can prevent HCV infection in vitro and in animal models. However, the effects of nAbs on an established HCV infection are unclear. Here, we demonstrate that three broadly nAbs, AR3A, AR3B and AR4A, delivered with adeno-associated viral (AAV) vectors can confer protection against viral challenge in humanized mice. Furthermore, we provide evidence that nAbs can abrogate an ongoing HCV infection in primary hepatocyte cultures and in a human liver chimeric mouse model. These results showcase a novel therapeutic approach to interfere with HCV infection exploiting a previously unappreciated need for HCV to continuously infect new hepatocytes in order to sustain chronicity. PMID:25232181

de Jong, Ype P.; Dorner, Marcus; Mommersteeg, Michiel C.; Xiao, Jing W.; Balazs, Alejandro B.; Robbins, Justin B.; Winer, Benjamin Y.; Gerges, Sherif; Vega, Kevin; Labitt, Rachael N.; Donovan, Bridget M.; Giang, Erick; Krishnan, Anuradha; Chiriboga, Luis; Charlton, Michael R.; Burton, Dennis R.; Baltimore, David; Law, Mansun; Rice, Charles M.; Ploss, Alexander

2015-01-01

297

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. PMID:25071320

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

2014-01-01

298

Treatment of Venezuelan Equine Encephalitis Virus Infection with (-)-Carbodine  

PubMed Central

Venezuelan equine encephalitis virus (VEEV) may cause encephalitis in humans, for which no FDA-approved antiviral treatment is available. Carbocyclic cytosine (carbodine) has broad-spectrum activity but toxicity has limited its utility. It was anticipated that one of the enantiomers of carbodine would show enhanced activity and reduced toxicity. The activity of the D-(-) enantiomer of carbodine [(-)-carbodine] was evaluated by infectious cell culture assay and was found to have a 50% effective concentration (EC50) of 0.2 ?g/ml against the TC-83 vaccine strain of VEEV in Vero cells, while the L-(+) enantiomer had no activity. Virus titer inhibition correlated with intracellular cytidine triphosphate reduction after treatment with (-)-carbodine, as determined by HPLC analysis. Pre-treatment with 200 mg/kg/d resulted in significant improvement in survival, virus load in the brain, weight change, and mean day to death in a mouse model of TC-83 VEEV disease. A single dose of (-)-Carbodine resulted in a slight extension of mean time to death in mice infected with wild-type VEEV. Post-virus exposure treatment with (-)-carbodine was effective in significantly improving disease parameters in mice infected with TC-83 VEEV when treatment was initiated as late as 4 days post-virus installation (dpi). It is remarkable that (-)-carbodine is effective when initiated after the establishment of brain infection. PMID:18675850

Bowen, Richard A.; Rao, Jagadeeshwar R.; Day, Craig; Shafer, Kristiina; Smee, Donald F.; Morrey, John D.; Chu, Chung K.

2008-01-01

299

Virus infection in remnant native bunchgrasses from invaded California grasslands.  

PubMed

This study examined the effects of infection with barley and cereal yellow dwarf viruses (BYDVs) on wild grass species in California, a region in which native perennial bunchgrasses have been largely replaced by exotic annual grasses. We sought to determine whether these widespread viruses compromise the fitness of wild hosts and thus have the potential to influence grassland dynamics. Plant viruses have been long overlooked in ecological studies, and their influence on wild hosts has often been assumed to be minimal. We examined the short-term and long-term consequences of infection on field-grown individuals from 18 different populations of wild California grasses (from seven native and one exotic species). Barley yellow dwarf virus infection was aggressive in most hosts and markedly impaired host fitness by reducing growth, survivorship, and fecundity. Previous work indicates that the presence of exotic grasses can more than double BYDV incidence in natives. Given the ubiquity of BYDVs, our results suggest that apparent competition and other virus-mediated processes may influence interactions among native and exotic grasses and potentially contribute to shifts in grassland community composition. PMID:16159335

Malmstrom, C M; Hughes, C C; Newton, L A; Stoner, C J

2005-10-01

300

Ganjam virus/Nairobi sheep disease virus induces a pro-inflammatory response in infected sheep  

PubMed Central

Partly due to climate change, and partly due to changes of human habitat occupation, the impact of tick-borne viruses is increasing. Nairobi sheep disease virus (NSDV) and Ganjam virus (GV) are two names for the same virus, which causes disease in sheep and goats and is currently known to be circulating in India and East Africa. The virus is transmitted by ixodid ticks and causes a severe hemorrhagic disease. We have developed a real-time PCR assay for the virus genome and validated it in a pilot study of the pathogenicity induced by two different isolates of NSDV/GV. One isolate was highly adapted to tissue culture, grew in most cell lines tested, and was essentially apathogenic in sheep. The second isolate appeared to be poorly adapted to cell culture and retained pathogenicity in sheep. The real-time PCR assay for virus easily detected 4 copies or less of the viral genome, and allowed a quantitative measure of the virus in whole blood. Measurement of the changes in cytokine mRNAs showed similar changes to those observed in humans infected by the closely related virus Crimean Congo hemorrhagic fever virus. PMID:23083136

2012-01-01

301

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. PMID:20113567

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

2010-01-01

302

West Nile Virus Infection in Humans and Horses, Cuba  

PubMed Central

A surveillance system to detect West Nile virus (WNV) was established in Cuba in 2002. WNV infection was confirmed by serologic assays in 4 asymptomatic horses and 3 humans with encephalitis in 2003 and 2004. These results are the first reported evidence of WNV activity in Cuba. PMID:16707068

Guzmán, Maria Guadalupe; Fernández, Roberto; Llop, Alina; Dickinson, Félix Orlando; Pérez, Daniel; Cruz, Raúl; González, Tayri; Estévez, Gonzalo; González, Hiram; Santos, Paulino; Kourí, Gustavo; Andonova, Maya; Lindsay, Robbin; Artsob, Harvey; Drebot, Michael

2006-01-01

303

Bovine Viral Diarrhea Virus Quasispecies during Persistent Infection  

Microsoft Academic Search

Analysis of viral genome sequences from two calves persistently infected with bovine viral diarrhea virus revealed a quasispecies distribution. The sequences encoding the glycoprotein E2 were variable, translating to a number of changes in predicted amino acid sequences. The NS3 region was found to be highly conserved in both animals. The number of E2 clones showing variant amino acids increased

Margaret E. Collins; Moira Desport; Joe Brownlie

1999-01-01

304

Antibody-Dependent Enhancement of Marburg Virus Infection  

PubMed Central

Background.?Marburg virus (MARV) and Ebola virus (EBOV) cause severe hemorrhagic fever in primates. Earlier studies demonstrated that antibodies to particular epitopes on the glycoprotein (GP) of EBOV enhanced virus infectivity in vitro. Methods.?To investigate this antibody-dependent enhancement (ADE) in MARV infection, we produced mouse antisera and monoclonal antibodies (mAbs) to the GPs of MARV strains Angola and Musoke. Results.?The infectivity of vesicular stomatitis virus pseudotyped with Angola GP in K562 cells was significantly enhanced in the presence of Angola GP antisera, whereas only minimal ADE activity was seen with Musoke GP antisera. This difference correlated with the percentage of hybridoma clones producing infectivity-enhancing mAbs. Using mAbs to MARV GP, we identified 3 distinct ADE epitopes in the mucinlike region on Angola GP. Interestingly, some of these antibodies bound to both Angola and Musoke GPs but showed significantly higher ADE activity for strain Angola. ADE activity depended on epitopes in the mucinlike region and glycine at amino acid position 547, present in the Angola but absent in the Musoke GP. Conclusions.?These results suggest a possible link between ADE and MARV pathogenicity and provide new insights into the mechanisms underlying ADE entry of filoviruses. PMID:21987779

Nakayama, Eri; Tomabechi, Daisuke; Matsuno, Keita; Kishida, Noriko; Yoshida, Reiko; Feldmann, Heinz

2011-01-01

305

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. PMID:11266303

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

306

Antiviral activity of alginate against infection by tobacco mosaic virus  

Microsoft Academic Search

In the course of searching for antiviral substances to tobacco mosaic virus (TMV), it was found that sodium alginate (Alg) had a high inhibitory activity against TMV infection. The addition of Alg to the inoculum solution greatly reduced the number of local lesions formed on Xanthi NN tobacco leaves. The degree of inhibition increased with Alg concentration and was higher

Yoh Sano

1999-01-01

307

Promoting Early Detection of Human Immunodeficiency Virus Infection Among Adolescents  

Microsoft Academic Search

W hile a significant and increasing number of adolescents are infected with the hu- man immunodeficiency virus (HIV), few youth are identified as seropositive and even fewer are linked to medical care and social services. If more youth were identified, transmission to sexual partners and offspring would be reduced and individuals could benefit from treatment. Prior to initiating wide-scale early

Mary Jane Rotheram-Borus; Donna Futterman

2000-01-01

308

Physiological effects of Squash vein yellowing virus infection on watermelon  

Technology Transfer Automated Retrieval System (TEKTRAN)

Squash vein yellowing virus (SqVYV) is the cause of viral watermelon vine decline. In this study, watermelon plants of different ages were inoculated with SqVYV to characterize the physiological response to infection and provide new insights into watermelon vine decline. Physiological responses to...

309

Influenza A virus and secondary bacterial infection in swine  

Technology Transfer Automated Retrieval System (TEKTRAN)

Influenza A virus (IAV) infection alone causes significant disease characterized by respiratory distress and poor growth in pigs. Endemic strains of IAV in North America pigs consist of the subtypes H1N1, H1N2, and H3N2. These circulating strains contain the triple reassortant internal gene (TRIG) c...

310

PREVENTION AND CONTROL OF RETICULOENDOTHELIOSIS VIRUS INFECTION: RATIONALE AND STRATEGIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Reticuloendotheliosis virus (REV) is a common retroviral infection of poultry that only rarely causes significant disease problems. Typically, the issue of control is dismissed as unnecessary for and not practiced in commercial flocks. Prevention is a more relevant issue and preventive measures ar...

311

Hepatitis B virus infection in medical and health care personnel.  

PubMed Central

Analysis of 51 cases of hepatitis B virus infection in health care workers admitted as patients to the liver unit over seven years showed three healthy carriers of hepatitis B virus, seven cases of fulminant hepatic persistent hepatitis, 17 cases of chronic active hepatitis (of whom 11 had cirrhosis), and five cases of hepatocellular carcinoma. To date 11 of these patients have died. Only 15 of the 51 patients had a history of direct occupational exposure and only three patients could recall specific inoculation injuries. In contrast, the source of infection was apparent in 32 of 50 consecutive cases of fulminant hepatic failure or acute hepatitis B in nonmedical staff. Since specific inoculation injuries are not the usual mode of infection ion medical staff and since only a few of the patients who are hepatitis B virus carriers will be detected by selective screening of "high-risk" patients, the overall risk of infection can be reduced only by stricter precautions in the handling of any patient's blood and by the use of hepatitis B virus vaccines for medical staff at high risk. PMID:6800450

Callender, M E; White, Y S; Williams, R

1982-01-01

312

The Mannose Receptor Mediates Dengue Virus Infection of Macrophages  

Microsoft Academic Search

Macrophages (MØ) and mononuclear phagocytes are major targets of infection by dengue virus (DV), a mosquito- borne flavivirus that can cause haemorrhagic fever in humans. To our knowledge, we show for the first time that the MØ mannose receptor (MR) binds to all four serotypes of DV and specifically to the envelope glycoprotein. Glycan analysis, ELISA, and blot overlay assays

Joanna L. Miller; Barend J. M. deWet; Luisa Martinez-Pomares; Catherine M. Radcliffe; Raymond A. Dwek; Pauline M. Rudd; Siamon Gordon

2008-01-01

313

Protective Effect of Dietary Xylitol on Influenza A Virus Infection  

PubMed Central

Xylitol has been used as a substitute for sugar to prevent cavity-causing bacteria, and most studies have focused on its benefits in dental care. Meanwhile, the constituents of red ginseng (RG) are known to be effective in ameliorating the symptoms of influenza virus infection when they are administered orally for 14 days. In this study, we investigated the effect of dietary xylitol on influenza A virus infection (H1N1). We designed regimens containing various fractions of RG (RGs: whole extract, water soluble fraction, saponin and polysaccharide) and xylitol, and combination of xylitol with the RG fractions. Mice received the various combinations orally for 5 days prior to lethal influenza A virus infection. Almost all the mice died post challenge when xylitol or RGs were administered separately. Survival was markedly enhanced when xylitol was administered along with RGs, pointing to a synergistic effect. The effect of xylitol plus RG fractions increased with increasing dose of xylitol. Moreover, dietary xylitol along with the RG water soluble fraction significantly reduced lung virus titers after infection. Therefore, we suggest that dietary xylitol is effective in ameliorating influenza-induced symptoms when it is administered with RG fractions, and this protective effect of xylitol should be considered in relation to other diseases. PMID:24392148

Yin, Sun Young; Kim, Hyoung Jin; Kim, Hong-Jin

2014-01-01

314

Spatial analysis of feline immunodeficiency virus infection in cougars.  

PubMed

The cougar (Puma concolor) is a large predatory feline found widely in the Americas that is susceptible to feline immunodeficiency virus (FIV), a fast-evolving lentivirus found in wild feline species that is analogous to simian immunodeficiency viruses in wild primates and belongs to the same family of viruses as human immunodeficiency virus. FIV infection in cougars can lead to a weakened immune system that creates opportunities for other infecting agents. FIV prevalence and lineages have been studied previously in several areas in the western United States, but typically without spatially explicit statistical techniques. To describe the distribution of FIV in a sample of cougars located in the northern Rocky Mountain region of North America, we first used kernel density ratio estimation to map the log relative risk of FIV. The risk surface showed a significant cluster of FIV in northwestern Montana. We also used Bayesian cluster models for genetic data to investigate the spatial structure of the feline immunodeficiency virus with virus genetic sequence data. A result of the models was two spatially distinct FIV lineages that aligned considerably with an interstate highway in Montana. Our results suggest that the use of spatial information and models adds novel insight when investigating an infectious animal disease. The results also suggest that the influence of landscape features likely plays an important role in the spatiotemporal spread of an infectious disease within wildlife populations. PMID:21197421

Wheeler, David C; Waller, Lance A; Biek, Roman

2010-07-01

315

Influenza A virus infections in marine mammals and terrestrial carnivores.  

PubMed

Influenza A viruses (IAV), members of the Orthomyxoviridae, cover a wide host spectrum comprising a plethora of avian and, in comparison, a few mammalian species. The viral reservoir and gene pool are kept in metapopulations of aquatic wild birds. The mammalian-adapted IAVs originally arose by transspecies transmission from avian sources. In swine, horse and man, species-adapted IAV lineages circulate independently of the avian reservoir and cause predominantly respiratory disease of highly variable severity. Sporadic outbreaks of IAV infections associated with pneumonic clinical signs have repeatedly occurred in marine mammals (harbour seals [Phoca vitulina]) off the New England coast of the U.S.A. due to episodic transmission of avian IAV. However, no indigenous marine mammal IAV lineages are described. In contrast to marine mammals, avian- and equine-derived IAVs have formed stable circulating lineages in terrestrial carnivores: IAVs of subtype H3N2 and H3N8 are found in canine populations in South Korea, China, and the U.S.A. Experimental infections revealed that dogs and cats can be infected with an even wider range of avian IAVs. Cats, in particular, also proved susceptible to native infection with human pandemic H1N1 viruses and, according to serological data, may be vulnerable to infection with further human-adapted IAVs. Ferrets are susceptible to a variety of avian and mammalian IAVs and are an established animal model of human IAV infection. Thus, a potential role of pet cats, dogs and ferrets as mediators of avian-derived viruses to the human population does exist. A closer observation for influenza virus infections and transmissions at this animal-human interface is indicated. PMID:24511825

Harder, Timm C; Siebert, Ursula; Wohlsein, Peter; Vahlenkamp, Thomas

2013-01-01

316

Autoimmunity-related demyelination in infection by Japanese encephalitis virus  

PubMed Central

Japanese encephalitis (JE) virus is the most common cause of epidemic viral encephalitis in the world. The virus mainly infects neuronal cells and causes an inflammatory response after invasion of the parenchyma of the brain. The death of neurons is frequently observed, in which demyelinated axons are commonly seen. The mechanism that accounts for the occurrence of demyelination is ambiguous thus far. With a mouse model, the present study showed that myelin-specific antibodies appeared in sera, particularly in those mice with evident symptoms. Meanwhile, specific T cells proliferating in response to stimulation by myelin basic protein (MBP) was also shown in these mice. Taken together, our results suggest that autoimmunity may play an important role in the destruction of components, e.g., MBP, of axon-surrounding myelin, resulting in demyelination in the mouse brain after infection with the JE virus. PMID:21356046

2011-01-01

317

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. PMID:23884722

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

2014-01-01

318

CHARACTERIZATION OF THREE NOVEL VIRUSES INFECTING RASPBERRY  

Technology Transfer Automated Retrieval System (TEKTRAN)

During routine graft indexing at the USDA-ARS Horticultural Crops Research Laboratory in Corvallis, Oregon, USA, a ‘Glen Clova’ plant that originated in Europe induced severe symptoms on indicator plants causing mottling, epinasty and apical necrosis. Testing for all Rubus viruses with available lab...

319

Equine Influenza A(H3N8) Virus Infection in Cats  

PubMed Central

Interspecies transmission of equine influenza A(H3N8) virus has resulted in establishment of a canine influenza virus. To determine if something similar could happen with cats, we experimentally infected 14 cats with the equine influenza A(H3N8) virus. All showed clinical signs, shed virus, and transmitted the virus to a contact cohort. PMID:25417790

Su, Shuo; Wang, Lifang; Fu, Xinliang; He, Shuyi; Hong, Malin; Zhou, Pei; Gray, Gregory

2014-01-01

320

Agrobacterium-mediated infectivity of cloned digitaria streak virus DNA.  

PubMed

A monomeric clone of double-stranded DNA synthesized in vitro DNA of the geminivirus Digitaria streak (DSV) was subcloned as a tandem dimeric unit into a binary vector of Agrobacterium tumefaciens, creating a plasmid pDS2. Inoculation of digitaria sanguinalis with A. tumefaciens carrying pDS2 resulted in viral infection. The symptoms, virus particles, and DNA forms obtained were indistinguishable from those of a natural DSV infection of D. sanguinalis. Inoculations have also induced infections in Zea mays and Avena sativa. The sequence of the Agrobacterium-mediated infectious clone of DSV has been determined. PMID:3341112

Donson, J; Gunn, H V; Woolston, C J; Pinner, M S; Boulton, M I; Mullineaux, P M; Davies, J W

1988-01-01

321

Human Ebola virus infection results in substantial immune activation.  

PubMed

Four Ebola patients received care at Emory University Hospital, presenting a unique opportunity to examine the cellular immune responses during acute Ebola virus infection. We found striking activation of both B and T cells in all four patients. Plasmablast frequencies were 10-50% of B cells, compared with less than 1% in healthy individuals. Many of these proliferating plasmablasts were IgG-positive, and this finding coincided with the presence of Ebola virus-specific IgG in the serum. Activated CD4 T cells ranged from 5 to 30%, compared with 1-2% in healthy controls. The most pronounced responses were seen in CD8 T cells, with over 50% of the CD8 T cells expressing markers of activation and proliferation. Taken together, these results suggest that all four patients developed robust immune responses during the acute phase of Ebola virus infection, a finding that would not have been predicted based on our current assumptions about the highly immunosuppressive nature of Ebola virus. Also, quite surprisingly, we found sustained immune activation after the virus was cleared from the plasma, observed most strikingly in the persistence of activated CD8 T cells, even 1 mo after the patients' discharge from the hospital. These results suggest continued antigen stimulation after resolution of the disease. From these convalescent time points, we identified CD4 and CD8 T-cell responses to several Ebola virus proteins, most notably the viral nucleoprotein. Knowledge of the viral proteins targeted by T cells during natural infection should be useful in designing vaccines against Ebola virus. PMID:25775592

McElroy, Anita K; Akondy, Rama S; Davis, Carl W; Ellebedy, Ali H; Mehta, Aneesh K; Kraft, Colleen S; Lyon, G Marshall; Ribner, Bruce S; Varkey, Jay; Sidney, John; Sette, Alessandro; Campbell, Shelley; Ströher, Ute; Damon, Inger; Nichol, Stuart T; Spiropoulou, Christina F; Ahmed, Rafi

2015-04-14

322

A virus-like particle vaccine for epidemic Chikungunya virus protects nonhuman primates against infection.  

PubMed

Chikungunya virus (CHIKV) has infected millions of people in Africa, Europe and Asia since this alphavirus reemerged from Kenya in 2004. The severity of the disease and the spread of this epidemic virus present a serious public health threat in the absence of vaccines or antiviral therapies. Here, we describe a new vaccine that protects against CHIKV infection of nonhuman primates. We show that selective expression of viral structural proteins gives rise to virus-like particles (VLPs) in vitro that resemble replication-competent alphaviruses. Immunization with these VLPs elicited neutralizing antibodies against envelope proteins from alternative CHIKV strains. Monkeys immunized with VLPs produced high-titer neutralizing antibodies that protected against viremia after high-dose challenge. We transferred these antibodies into immunodeficient mice, where they protected against subsequent lethal CHIKV challenge, indicating a humoral mechanism of protection. Immunization with alphavirus VLP vaccines represents a strategy to contain the spread of CHIKV and related pathogenic viruses in humans. PMID:20111039

Akahata, Wataru; Yang, Zhi-Yong; Andersen, Hanne; Sun, Siyang; Holdaway, Heather A; Kong, Wing-Pui; Lewis, Mark G; Higgs, Stephen; Rossmann, Michael G; Rao, Srinivas; Nabel, Gary J

2010-03-01

323

Antiviral Activity of HPMPC (Cidofovir) Against ORF Virus Infected Lambs  

PubMed Central

(S)-9-[3-hydroxy-2-(phosphonomethoxy)propyl]-2,6-diaminopurine (HPMPC, cidofovir, CDV, Vistide®) is an acyclic nucleoside analogue with a potent and selective activity against a broad spectrum of DNA viruses including the poxviruses. In this study we present the results of different treatment regimens in lambs experimentally infected with orf virus with different cidofovir formulations prepared in Beeler basis and Unguentum M. Our results show that choice of excipient, concentration of cidofovir and treatment regimen were all important to the clinical outcome of the therapy. Whilst one particular regimen appeared to exacerbate the lesion, treatment with 1% w/v cidofovir cream, prepared in Beeler Basis, for 4 consecutive days did result in milder lesions that resolved more quickly than untreated lesions. Furthermore the scabs of the treated animals contained significantly lower amounts of viable virus meaning there should be less contamination of the environment with virus than would normally occur. PMID:17049627

Scagliarini, A.; McInnes, C.J.; Gallina, L.; Dal, Pozzo F.; Scagliarini, L.; Snoeck, R.; Prosperi, S.; Sales, J.; Gilray, J.A.; Nettleton, P.F.

2007-01-01

324

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. PMID:8551590

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

1996-01-01

325

Hepatitis B virus infection in Northern Ireland 1970-1987.  

PubMed Central

In the 18 years between 1970 and 1987, 504 patients were found to have hepatitis B surface antigen (HBsAg) in their blood. Acute hepatitis was present in 184 patients and six died (3.3%). The annual incidence of acute hepatitis B virus infection in Northern Ireland was about one-quarter that of England and Wales. A decrease in acute infection occurred in 1986-87, while in England and Wales acute infection has fallen by more than half since the peak in 1984. Hepatitis B virus infection in health care staff and patients in high risk groups were reviewed: 32% were in those of foreign origin or who had known foreign contacts. In blood donors there was a marked fall in incidence of hepatitis B surface antigen carriage from 1982 onwards: the incidence in antenatal patients and those screened for rubella antibody (mainly females) was half that of new blood donors in 1972-81. Carrier rates in blood donors and antenatal patients were less than those from other parts of the United Kingdom. All indices show that Northern Ireland has a lower incidence of hepatitis B virus infection than the rest of the United Kingdom. PMID:2788948

Connolly, J. H.; McClelland, W. M.; O'Neill, H. J.; Crowley, D.

1989-01-01

326

Molecular diagnosis of Baylisascaris schroederi infections in giant panda (Ailuropoda melanoleuca) feces using PCR.  

PubMed

The helminth Baylisascaris schroederi is one of the most harmful parasites infecting giant pandas (Ailuropoda melanoleuca). It is therefore important to develop an exact diagnostic technique to detect this parasite. Using a known number (1, 2, 3, 4, 5, 10, 25, 50, 100) of feces-isolated B. schroederi egg and adult DNA, we developed a PCR to detect a portion of the mitochondrial 12S rRNA and applied it to giant panda fecal samples. The method was sufficiently sensitive to detect B. schroederi DNA from isolated eggs in a fecal sample with a detection threshold of one egg. We detected B. schroederi in 88% of fecal samples, 30% higher than the conventional flotation technique. No cross-reactivity with other common nematode DNA was detected. Our PCR assay may constitute a valuable alternative for the diagnosis of B. schroederi infections. PMID:24502740

Zhou, Xuan; Yu, Hua; Wang, Ning; Xie, Yue; Liang, Yi-nan; Li, De-sheng; Wang, Cheng-dong; Chen, Si-jie; Yan, Yu-bo; Gu, Xiao-bin; Wang, Shu-xian; Peng, Xue-rong; Yang, Guang-you

2013-10-01

327

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. PMID:24509809

Fénéant, Lucie; Levy, Shoshana; Cocquerel, Laurence

2014-01-01

328

Chronic ulcerative herpes simplex virus infection of the vulva.  

PubMed

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. PMID:23271993

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

2012-09-01

329

CD81 and hepatitis C virus (HCV) infection.  

PubMed

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. PMID:24509809

Fénéant, Lucie; Levy, Shoshana; Cocquerel, Laurence

2014-02-01

330

[West nile virus infection: re-emergent disease in Croatia].  

PubMed

West Nile virus (WNV) is a small, enveloped, spherical virus that belongs to the family Flaviviridae, genus Flavivirus, Japanese encephalitis serocomplex. Natural reservoirs of WNV are birds, and the main vectors are mosquitoes of the genus Culex. There are seven genetic lineages of WNV. Lineages 1 and 2 are the most widely distributed (Africa, North and South America, Europe, Asia and Australia). About 80% of infections are asymptomatic. In 20% of patients nonspecific febrile disease occurs (West Nile fever). Less than 1% of infected persons will develop neuroinvasive WNV disease (meningitis, encephalitis, and poliomyelitis). In Croatia, antibodies to WNV were demonstrated in humans,bears and horses. In August-September 2012 clinical cases of human WNV neuroinvasive disease and asymptomatic acute infection in horses were reported for the first time in three eastern Croatian counties. The diagnosis was confirmed by serologic tests (enzyme immunoassay, IgG avidity, plaque-reduction neutralization test). PMID:23898697

Vilibi?-Cavlek, Tatjana; Barbi?, Ljubo; Ljubin-Sternak, Suncanica; Pem-Novosel, Iva; Stevanovi?, Vladimir; Gjenero-Margan, Ira; Mlinari?-Galinovi?, Gordana

2013-01-01

331

Virus antibody dynamics in primary and secondary dengue infections.  

PubMed

Dengue viral infections show unique infection patterns arising from its four serotypes, (DENV-1,2,3,4). Its effects range from simple fever in primary infections to potentially fatal secondary infections. We analytically and numerically analyse virus dynamics and humoral response in a host during primary and secondary dengue infection for long periods using micro-epidemic models. The models presented here incorporate time delays, antibody dependent enhancement, a dynamic switch and a correlation factor between different DENV serotypes. We find that the viral load goes down to undetectable levels within 7-14 days as is observed for dengue infection, in both cases. For primary infection, the stability analysis of steady states shows interesting dependence on the time delay involved in the production of antibodies from plasma cells. We demonstrate the existence of a critical value for the immune response parameter, beyond which the infection gets completely cured. For secondary infections with a different serotype, the homologous antibody production is enhanced due to the influence of heterologous antibodies. The antibody production is also controlled by the correlation factor, which is a measure of similarities between the different DENV serotypes involved. Our results agree with clinically observed humoral responses for primary and secondary infections. PMID:24384697

Gujarati, Tanvi P; Ambika, G

2014-12-01

332

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. PMID:24756136

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

2014-01-01

333

[Nosocomial viral infections. Hepatitis, herpes and flu viruses].  

PubMed

Viruses account for about 5% of all nosocomial infections. Viral cross-infection is most common in infants and children, but also occurs in other groups, including the elderly, institutionalized persons of all ages, immunecompromised hosts, and patients with underlying chronic pulmonary, renal, or cardiac disease. These infections are associated with extended length of hospital stay, as well as considerable morbidity and mortality. The new technology of rapid viral diagnosis allows a more timely and accurate recognition of viral infections, even in the smaller hospital with limited laboratory resources. Early recognition of viral diseases should, in turn, permit the introduction, and further evaluation of specific measures for their control. Influenza vaccination of health care workers is an important prevention strategy for nosocomial infection. PMID:23906752

Martinez, José Antonio; Pumarola, Tomàs

2013-01-01

334

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. PMID:24987312

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

2014-01-01

335

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

336

A Cellular Model to Explain the Pathogenesis of Infection by the Hepatitis B Virus  

E-print Network

A Cellular Model to Explain the Pathogenesis of Infection by the Hepatitis B Virus ROBERT J. H; revised 10 November 1993 ABSTRACT The natural history of infection by the hepatitis B virus (HBV) depends transient infection to subclinical chronic hepatitis. Persistent infection often leads to the development

Nowak, Martin A.

337

Concomitant Human Infections with 2 Cowpox Virus Strains in Related Cases, France, 2011  

PubMed Central

We investigated 4 related human cases of cowpox virus infection reported in France during 2011. Three patients were infected by the same strain, probably transmitted by imported pet rats, and the fourth patient was infected by another strain. The 2 strains were genetically related to viruses previously isolated from humans with cowpox infection in Europe. PMID:24274113

Ducournau, Corinne; Ferrier-Rembert, Audrey; Ferraris, Olivier; Joffre, Aurélie; Favier, Anne-Laure; Flusin, Olivier; Van Cauteren, Dieter; Kecir, Kaci; Auburtin, Brigitte; Védy, Serge; Bessaud, Maël

2013-01-01

338

Cutaneous Co-infected Cytomegalovirus and Herpes Simplex Virus Perigenital Ulcers in Human Immunodeficiency Virus Patients.  

PubMed

There is uncertainty regarding the pathogenic nature of cytomegalovirus in cutaneous lesions co-infected with herpes simplex virus. It is widely believed that herpes simplex virus is the main pathogenic factor in such lesions and that cytomegalovirus plays little if any role. There are, however, isolated case reports that describe cytomegalovirus as an important driving pathogen in such lesions. The authors present two human immunodeficiency virus patients who have cytomegalovirus and herpes simplex virus co-infected perigenital ulcers, one of whom improved on valacyclovir, while the other, who was already on valacyclovir for chronic herpes simplex virus suppression, showed no improvement with a single dose of cidofovir. He only showed rapid improvement when treated with valganciclovir. The latter patient underscores the viewpoint that at least in some cases, cytomegalovirus may be an important driving force behind the formation of such lesions. The authors therefore recommend that clinicians be aware of the possible pathogenic role of cytomegalovirus in these ulcers, and, in nonhealing ulcers, use anti-cytomegalovirus agents to prevent the onset of systemic disease. These results warrant further study of the pathogenesis of cytomegalovirus in co-infected herpes simplex virus ulcers. PMID:24155993

Schoenfeld, Jason; Cannon, Sarah; Cam, Kristin; Keller, Matthew

2013-10-01

339

Viruses in fungi: infection of yeast with the K1 and K2 killer viruses.  

PubMed Central

We demonstrate here that yeast killer viruses, previously thought to be transmitted only by cytoplasmic mixing during division, mating, or other induced forms of cell fusion, are capable of extracellular transmission. Viral particles from standard K1 and K2 killer strains were used to inoculate sensitive cells of Saccharomyces cerevisiae, rendered competent by spheroplasting, lithium acetate treatment, or by natural mating. Extracellular transmission of the killer viruses was judged by the following criteria and controls. Filter-sterilized virus inocula were shown to be free of viable yeast cells, and host cells treated in the absence of added virus did not yield killer progeny. Infected clones originating from spheroplasts or lithium acetate-treated cells were shown to possess the genotype of the host strain and the killer phenotype of the infecting virus. Infected clones derived from complementary mating pairs were found to be wild-type diploids, whose meiotic segregants exhibited 2:2 segregation for unlinked nutritional markers and 4:0 segregation for the killer phenotype. This technique is generally applicable to the study of interactions between yeast viruses and different hosts and suggests that extracellular transmission may be a natural route for the inheritance and dissemination of mycoviruses. Images PMID:3295880

el-Sherbeini, M; Bostian, K A

1987-01-01

340

Health care-associated hepatitis C virus infection  

PubMed Central

Hepatitis C virus (HCV) is a blood-borne pathogen that has a worldwide distribution and infects millions of people. Care-associated HCV infections represented a huge part of hepatitis C burden in the past via contaminated blood and unsafe injections and continue to be a serious problem of public health. The present review proposes a panorama of health care-associated HCV infections via the three mode of contamination that have been identified: (1) infected patient to non-infected patient; (2) infected patient to non-infected health care worker (HCW); and (3) infected HCW to non infected patient. For each condition, the circumstances of contamination are described together with the means to prevent them. As a whole, the more important risk is represented by unsafe practices regarding injections, notably with the improper use of multidose vials used for multiple patients. The questions of occupational exposures and infected HCWs are also discussed. In terms of prevention and surveillance, the main arm for combating care-associated HCV infections is the implementation of standard precautions in all the fields of cares, with training programs and audits to verify their good application. HCWs must be sensitized to the risk of blood-borne pathogens, notably by the use of safety devices for injections and good hygiene practices in the operating theatre and in all the invasive procedures. The providers performing exposed-prone procedures must monitor their HCV serology regularly in order to detect early any primary infection and to treat it without delay. With the need to stay vigilant because HCV infection is often a hidden risk, it can be hoped that the number of people infected by HCV via health care will decrease very significantly in the next years. PMID:25516637

Pozzetto, Bruno; Memmi, Meriam; Garraud, Olivier; Roblin, Xavier; Berthelot, Philippe

2014-01-01

341

Malignant syphilis with human immunodeficiency virus infection  

PubMed Central

Malignant syphilis or Lues maligna, commonly reported in the pre-antibiotic era, has now seen a resurgence with the advent of human immunodeficiency virus (HIV). Immunosuppression and sexual promiscuity set the stage for this deadly association of HIV and Treponema pallidum that can manifest atypically and can prove to cause diagnostic problems. We report one such case in a 30-year-old female who responded favorably to treatment with penicillin. PMID:23130209

Rajan, Jiby; Prasad, P. V. S.; Chockalingam, K.; Kaviarasan, P. K.

2011-01-01

342

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 Central

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

2013-01-01

343

mRNA maturation in giant viruses: variation on a theme.  

PubMed

Giant viruses from the Mimiviridae family replicate entirely in their host cytoplasm where their genes are transcribed by a viral transcription apparatus. mRNA polyadenylation uniquely occurs at hairpin-forming palindromic sequences terminating viral transcripts. Here we show that a conserved gene cluster both encode the enzyme responsible for the hairpin cleavage and the viral polyA polymerases (vPAP). Unexpectedly, the vPAPs are homodimeric and uniquely self-processive. The vPAP backbone structures exhibit a symmetrical architecture with two subdomains sharing a nucleotidyltransferase topology, suggesting that vPAPs originate from an ancestral duplication. A Poxvirus processivity factor homologue encoded by Megavirus chilensis displays a conserved 5'-GpppA 2'O methyltransferase activity but is also able to internally methylate the mRNAs' polyA tails. These findings elucidate how the arm wrestling between hosts and their viruses to access the translation machinery is taking place in Mimiviridae. PMID:25779049

Priet, Stéphane; Lartigue, Audrey; Debart, Françoise; Claverie, Jean-Michel; Abergel, Chantal

2015-04-20

344

Splenic Priming of Virus-Specific CD8 T Cells following Influenza Virus Infection  

PubMed Central

In healthy individuals, influenza virus (IAV) infection generally remains localized to the epithelial cells of the respiratory tract. Previously, IAV-specific effector CD8 T cells found systemically during the course of IAV infection were thought to have been primed in lung-draining lymph nodes with subsequent migration to other tissues. However, little is known about whether other lymphoid sites participate in the generation of virus-specific CD8 T cells during localized IAV infection. Here, we present evidence of early CD8 T cell priming in the spleen following respiratory IAV infection independent of lung-draining lymph node priming of T cells. Although we found early indications of CD8 T cell activation in the lymph nodes draining the respiratory tract, we also saw evidence of virus-specific CD8 T cell activation in the spleen. Furthermore, CD8 T cells primed in the spleen differentiated into memory cells of equivalent longevity and with similar recall capacity as CD8 T cells primed in the draining lymph nodes. These data showed that the spleen contributes to the virus-specific effector and memory CD8 T cell populations that are generated in response to respiratory infection. PMID:23388712

Turner, Damian L.; Bickham, Kara L.; Farber, Donna L.

2013-01-01

345

Herpes Simplex Virus Type 1 Renders Infected Cells Resistant to Cytotoxic T-Lymphocyte-Induced Apoptosis  

Microsoft Academic Search

Many viruses interfere with apoptosis of infected cells, presumably preventing cellular apoptosis as a direct response to viral infection. Since cytotoxic T lymphocytes (CTL) induce apoptosis of infected cells as part of the \\

KEITH R. JEROME; JONATHAN F. TAIT; DAVID M. KOELLE; LAWRENCE COREY

1998-01-01

346

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. PMID:24894438

2014-01-01

347

Revised MT-2006-115 Inhibition of hepatitis C virus infection in cell culture by small interfering RNAs  

E-print Network

Revised MT-2006-115 Inhibition of hepatitis C virus infection in cell culture by small interfering@pasteur.fr Short title: Silencing of hepatitis C virus infection * Manuscript #12;2 ABSTRACT Hepatitis C virus (HCV treatment of chronic HCV infections. #12;3 INTRODUCTION Persistent hepatitis C virus (HCV) infection

Paris-Sud XI, Université de

348

Dengue virus infection of erythroid precursor cells is modulated by both thalassemia trait status and virus adaptation.  

PubMed

Dengue is the most significant arthropod borne viral disease worldwide, and infection with the dengue virus causes a wide range of symptoms in humans, including bone marrow suppression. While the target cells of the virus remain poorly characterized, cells of the myeloid lineage have been shown to be important mediators of the disease. This study sought to determine whether erythroid precursor cells were susceptible to dengue virus infection, and whether erythroid cells from thalassemia trait carriers showed any protection against infection. Infection with a laboratory adapted high passage DENV-2 resulted in high levels of infection during certain stages of differentiation, and cells derived from thalassemia trait carriers showed significantly reduced susceptibility to dengue virus infection. Infection with low passage isolates resulted in only scattered cells showing evidence of infection, but high bystander apoptosis that was reduced by both a caspase 8 inhibitor and anti-tumor necrosis factor 1 receptor antibodies. PMID:25461532

Sornjai, Wannapa; Khungwanmaythawee, Kornpat; Svasti, Saovaros; Fucharoen, Suthat; Wintachai, Phitchayapak; Yoksan, Sutee; Ubol, Sukathida; Wikan, Nitwara; Smith, Duncan R

2014-12-01

349

The Natural History of Hepatitis C Virus (HCV) Infection  

PubMed Central

Hepatitis C virus (HCV) is a leading cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma, as well as the most common indication for liver transplantation in many countries. Although the incidence of hepatitis C infection has dramatically decreased during the past decade, the worldwide reservoir of chronically infected persons is estimated at 170 million, or 3% of the global population. There is much controversy surrounding the natural history of hepatitis C infection. The rate of chronic HCV infection is affected by a person's age, gender, race, and viral immune response. Approximately 75%-85% of HCV-infected persons will progress to chronic HCV infection, and are at risk for the development of extrahepatic manifestations, compensated and decompensated cirrhosis, and hepatocellular carcinoma (HCC). The rate of progression to cirrhosis is highly variable, and is influenced by several factors, including the amount of alcohol consumption, age of initial HCV infection, degree of inflammation and fibrosis on liver biopsy, HIV and HBV coinfection, and comordid conditions. An estimated 10%-15% of HCV-infected persons will advance to cirrhosis within the first 20 years. Persons with cirrhosis are at increased risk of developing HCC. An understanding of the natural history of hepatitis C is essential to effectively manage, treat, and counsel individuals with HCV infection. PMID:16614742

Chen, Stephen L.; Morgan, Timothy R.

2006-01-01

350

Drug-resistant herpes simplex virus in HIV infected patients.  

PubMed

Herpes simplex virus type 2 (HSV2) infection is a major source of morbidity in human immunodeficiency virus (HIV)-infected patients, since reactivations - whether symptomatic or asymptomatic - are associated with increased HIV viral load and viral shedding. Acyclovir, valacyclovir and famcyclovir are indicated for the treatment of HSV2 in HIV patients. This class of drugs has been shown to enhance survival in HIV-infected individuals. However, with the emergence of drug-resistant strains of HSV2, the rates of resistance among HIV patients are almost ten-fold those in immunocompetent individuals, comparing 0.6% to 6%. These HSV2 infections tend to be more severe and to recur. More ominously, disease progression of HIV is promoted by concurrent infection with HSV2. Intravenous foscarnet and cidofovir may be used for acyclovir-resistant HSV; however, resistance to these drugs has been documented. Newer therapies such as the toll-like receptor agonist imiquimod and immunomodulating dipeptides offer promise for the treatment of HSV2 in HIV-infected individuals. PMID:19111144

Lolis, Margarita S; González, Lenis; Cohen, Philip J; Schwartz, Robert A

2008-01-01

351

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. PMID:24803873

Ahn, Joseph

2014-01-01

352

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

353

Hepatitis B virus infection and metabolic syndrome: fact or fiction?  

PubMed

Although hepatitis C virus infection is known to be linked with insulin resistance, dyslipidemia, and hepatic steatosis, the relationship between hepatitis B virus (HBV) infection and metabolic factors remains unclear. HBV infection is a health problem worldwide, especially in endemic regions such as Asia and Africa. It induces liver decompensation, cirrhosis, hepatocellualr carcinoma, and premature mortality. The prevalence of metabolic syndrome continues to increase in parallel with the epidemic of obesity, which is closely associated with the development of diabetes, cardiovascular disease, or even cancer. The systemic review shows that chronic HBV infection protects against instead of promotes fatty liver. The mechanism is possibly due to a lower frequency of dyslipidemia profile in patients with chronic HBV infection. The association of HBV with metabolic syndrome, insulin resistance, and the risk of arteriosclerosis is still inconclusive. In addition, obesity, diabetes, and metabolic syndrome may accelerate the progression of liver disease in patients with chronic HBV infection and synergistically induce cirrhosis or even hepatocellualr carcinoma development. PMID:25092429

Wang, Chia-Chi; Tseng, Tai-Chung; Kao, Jia-Horng

2015-01-01

354

Naturally Occurring Animal Models of Human Hepatitis E Virus Infection  

PubMed Central

Hepatitis E virus (HEV) is a single-stranded, positive-sense RNA virus in the family Hepeviridae. Hepatitis E caused by HEV is a clinically important global disease. There are currently four well-characterized genotypes of HEV in mammalian species, although numerous novel strains of HEV likely belonging to either new genotypes or species have recently been identified from several other animal species. HEV genotypes 1 and 2 are limited to infection in humans, whereas genotypes 3 and 4 infect an expanding host range of animal species and are zoonotic to humans. Historical animal models include various species of nonhuman primates, which have been indispensable for the discovery of human HEV and for understanding its pathogenesis and course of infection. With the genetic identification and characterization of animal strains of HEV, a number of naturally occurring animal models such as swine, chicken, and rabbit have recently been developed for various aspects of HEV research, including vaccine trials, pathogenicity, cross-species infection, mechanism of virus replication, and molecular biology studies. Unfortunately, the current available animal models for HEV are still inadequate for certain aspects of HEV research. For instance, an animal model is still lacking to study the underlying mechanism of severe and fulminant hepatitis E during pregnancy. Also, an animal model that can mimic chronic HEV infection is critically needed to study the mechanism leading to chronicity in immunocompromised individuals. Genetic identification of additional novel animal strains of HEV may lead to the development of better naturally occurring animal models for HEV. This article reviews the current understanding of animal models of HEV infection in both natural and experimental infection settings and identifies key research needs and limitations. PMID:24936039

Yugo, Danielle M.; Cossaboom, Caitlin M.; Meng, Xiang-Jin

2014-01-01

355

75 FR 55797 - Draft Guidance for Industry on Chronic Hepatitis C Virus Infection: Developing Direct-Acting...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Guidance for Industry on Chronic Hepatitis C Virus Infection: Developing Direct-Acting...industry entitled ``Chronic Hepatitis C Virus Infection: Developing Direct-Acting...with specific steps in the hepatitis C virus (HCV) replication cycle. The...

2010-09-14

356

Feline Immunodeficiency Virus Orf-A Is Required for Virus Particle Formation and Virus Infectivity  

PubMed Central

The orf-A (orf-2) gene of feline immunodeficiency virus (FIV) is a small open reading frame predicted to encode a 77-amino-acid protein that contains putative domains similar to those of the ungulate lentiviral Tat protein. Orf-A is reported to be critical for efficient viral replication in vitro and in vivo. A series of FIV-pPPR-derived proviruses with in-frame deletions and point mutations within orf-A were constructed and tested for replication in feline lymphoid cells. Orf-A mutant proviruses were also tested for viral gene and protein expression, viral particle formation, and virion infectivity. Deletions within orf-A severely restricted FIV replication in feline peripheral blood mononuclear cells (PBMC) and interleukin-2-dependent T-cell lines. In addition, substitutions of alanines for leucines in the putative leucine-rich domain, for cysteines in the putative cysteine-rich domain, and for a tryptophan at position 43 in Orf-A restricted the replication of FIV mutants. Deletions and point mutations in orf-A imposed a small effect or no effect on FIV long-terminal-repeat-driven viral gene expression and had no effect on viral protein expression. However, release of cell-free, virion-associated viral RNA in supernatants from cells transfected with orf-A mutant proviruses was severely restricted but was rescued by cotransfection with a wild-type Orf-A expression vector. In addition, virions derived from orf-A mutant proviruses expressed reduced infectivity for feline PBMC. Our findings suggest that Orf-A functions involve multiple steps of the FIV life cycle including both virion formation and infectivity. Furthermore, these observations suggest that Orf-A represents an FIV-encoded analog more similar to the accessory gene vpr, vpu, or nef than to the regulatory gene tat encoded by the primate lentiviruses. PMID:12885901

Gemeniano, Malou C.; Sawai, Earl T.; Leutenegger, Christian M.; Sparger, Ellen E.

2003-01-01

357

Bacterial vaginosis and human immunodeficiency virus infection  

Microsoft Academic Search

Epidemiologic studies indicate that bacterial vaginosis (BV), a common alteration of lower genital tract flora in women, is associated with increased susceptibility to HIV infection. Other recent studies show that HIV is detected more frequently and at higher levels in the lower genital tract of HIV-seropositive women with BV. In vitro studies show that genital tract secretions from women with

Gregory T Spear; Elizabeth St John; M Reza Zariffard

2007-01-01

358

Leukocytoclastic Vasculitis Associated with Influenza A Virus Infection  

PubMed Central

Leukocytoclastic vasculitis (LCV) usually presents palpable purpura characterized by inflammation of vessel walls and fragmentation of nuclei. Various conditions can cause LCV, and it can be induced by influenza A virus infection. We report a 2-yr-old Korean girl who presented palpable purpuric and hemorrhagic lesions with fever. She was diagnosed as LCV by skin biopsy, and influenza A virus was isolated from nasopharyngeal swab. She was treated with oseltamivir (Tamiflu®) and prednisolone with dramatic effect of vasculitis and fever. PMID:23255867

Lee, Hyo Jin; Choi, Jong Soo; Kim, Ki Hong

2012-01-01

359

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

360

Soluble CD4 enhances simian immunodeficiency virus SIVagm infection.  

PubMed Central

The CD4 molecule is expressed on T-helper cells and serves as the cellular receptor for the human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) and for the simian immunodeficiency viruses SIVmac and SIVagm. HIV-1, HIV-2, and SIVmac infectivity can be blocked by monoclonal antibodies (MAbs) directed against the CD4 molecule and by soluble CD4 proteins (sCD4). In the present study, we demonstrated not only lack of inhibition, but 10- to 100-fold sCD4-dependent enhancement of SIVagm infectivity of human T-cell lymphoma lines, although SIVagm infection was blocked by MAbs OKT4a and Leu3a. SIVagm enhancement with sCD4 was suppressed by MAbs OKT4a and Leu3a to levels observed without addition of sCD4. The infectivity of all four tested SIVagm variants was enhanced by sCD4 on all tested lymphoma cell lines. These results suggest a second step (second or secondary receptor) required for enhancing virus entry into the cell and may have serious implications for approaches to the treatment of acquired immunodeficiency syndrome on the basis of modified sCD4 molecules. PMID:1700834

Werner, A; Winskowsky, G; Kurth, R

1990-01-01

361

Innate immune interferon responses to human immunodeficiency virus-1 infection.  

PubMed

Type I interferon (IFN) responses represent the canonical host innate immune response to viruses, which serves to upregulate expression of antiviral restriction factors and augment adaptive immune defences. There is clear evidence for type I IFN activity in both acute and chronic HIV-1 infection in vivo, and plasmacytoid dendritic cells have been identified as one important source for these responses, through innate immune detection of viral RNA by Toll-like receptor 7. In addition, new insights into the molecular mechanisms that trigger induction of type I IFNs suggest innate immune receptors for viral DNA may also mediate these responses. It is widely recognised that HIV-1 restriction factors share the characteristic of IFN-inducible expression, and that the virus has evolved to counteract these antiviral mechanisms. However, in some target cells, such as macrophages, IFN can still effectively restrict virus. In this context, HIV-1 shows the ability to evade innate immune recognition and thereby avoid induction of type I IFN in order to successfully establish productive infection. The relative importance of evasion of innate immune detection and evasion of IFN-inducible restriction in the natural history of HIV-1 infection is not known, and the data suggest that type I IFN responses may play a role in both viral control and in the immunopathogenesis of progressive disease. Further study of the relationship between HIV-1 infection and type I IFN responses is required to unravel these issues and inform the development of novel therapeutics or vaccine strategies. PMID:22359246

Hughes, Rose; Towers, Greg; Noursadeghi, Mahdad

2012-07-01

362

Serological Evidence of Ebola Virus Infection in Indonesian Orangutans  

PubMed Central

Ebola virus (EBOV) and Marburg virus (MARV) belong to the family Filoviridae and cause severe hemorrhagic fever in humans and nonhuman primates. Despite the discovery of EBOV (Reston virus) in nonhuman primates and domestic pigs in the Philippines and the serological evidence for its infection of humans and fruit bats, information on the reservoirs and potential amplifying hosts for filoviruses in Asia is lacking. In this study, serum samples collected from 353 healthy Bornean orangutans (Pongo pygmaeus) in Kalimantan Island, Indonesia, during the period from December 2005 to December 2006 were screened for filovirus-specific IgG antibodies using a highly sensitive enzyme-linked immunosorbent assay (ELISA) with recombinant viral surface glycoprotein (GP) antigens derived from multiple species of filoviruses (5 EBOV and 1 MARV species). Here we show that 18.4% (65/353) and 1.7% (6/353) of the samples were seropositive for EBOV and MARV, respectively, with little cross-reactivity among EBOV and MARV antigens. In these positive samples, IgG antibodies to viral internal proteins were also detected by immunoblotting. Interestingly, while the specificity for Reston virus, which has been recognized as an Asian filovirus, was the highest in only 1.4% (5/353) of the serum samples, the majority of EBOV-positive sera showed specificity to Zaire, Sudan, Cote d’Ivoire, or Bundibugyo viruses, all of which have been found so far only in Africa. These results suggest the existence of multiple species of filoviruses or unknown filovirus-related viruses in Indonesia, some of which are serologically similar to African EBOVs, and transmission of the viruses from yet unidentified reservoir hosts into the orangutan populations. Our findings point to the need for risk assessment and continued surveillance of filovirus infection of human and nonhuman primates, as well as wild and domestic animals, in Asia. PMID:22815803

Nidom, Reviany V.; Alamudi, Mohamad Y.; Daulay, Syafril; Dharmayanti, Indi N. L. P.; Dachlan, Yoes P.; Amin, Mohamad; Igarashi, Manabu; Miyamoto, Hiroko; Yoshida, Reiko; Takada, Ayato

2012-01-01

363

Humoral immune response to primary rubella virus infection.  

PubMed

An assay capable of distinguishing between the immune response generated by recent exposure to rubella virus and the immune response existing as a result of past exposure or immunization is required for the diagnosis of primary rubella virus infection, especially in pregnant women. Avidity assays, which are based on the premise that chaotropic agents can be used to selectively dissociate the low-avidity antibodies generated early in the course of infection, have become routinely used in an effort to accomplish this. We have thoroughly investigated the immunological basis of an avidity assay using a viral lysate-based assay and an enzyme-linked immunosorbent assay (ELISA) based on a peptide analogue of the putative immunodominant region of the E1 glycoprotein (E1208-239). The relative affinities of the antibodies directed against E1208-239 were measured by surface plasmon resonance and were found to correlate well with the avidity index calculated from the ELISA results. We found that the immune response generated during primary rubella virus infection consists of an initial low-affinity peak of immunoglobulin M (IgM) reactivity followed by transient peaks of low-avidity IgG3 and IgA reactivity. The predominant response is an IgG1 response which increases in concentration and affinity progressively over the course of infection. Incubation with the chaotropic agent used in the avidity assay abolished the detection of the early low-affinity peaks of IgM, IgA, and IgG3 reactivity while leaving the high-affinity IgG1 response relatively unaffected. The present study supported the premise that avidity assays based on appropriate antigens can be useful to confirm primary rubella virus infection. PMID:16522781

Wilson, Kim M; Di Camillo, Carlie; Doughty, Larissa; Dax, Elizabeth M

2006-03-01

364

Antiviral therapy for human immunodeficiency virus infections.  

PubMed Central

Depending on the stage of their intervention with the viral replicative cycle, human immunodeficiency virus inhibitors could be divided into the following groups: (i) adsorption inhibitors (i.e., CD4 constructs, polysulfates, polysulfonates, polycarboxylates, and polyoxometalates), (ii) fusion inhibitors (i.e., plant lectins, succinylated or aconitylated albumins, and betulinic acid derivatives), (iii) uncoating inhibitors (i.e., bicyclams), (iv) reverse transcription inhibitors acting either competitively with the substrate binding site (i.e., dideoxynucleoside analogs and acyclic nucleoside phosphonates) or allosterically with a nonsubstrate binding site (i.e., non-nucleoside reverse transcriptase inhibitors), (v) integration inhibitors, (vi) DNA replication inhibitors, (vii) transcription inhibitors (i.e., antisense oligodeoxynucleotides and Tat antagonists), (viii) translation inhibitors (i.e., antisense oligodeoxynucleotides and ribozymes), (ix) maturation inhibitors (i.e., protease inhibitors, myristoylation inhibitors, and glycosylation inhibitors), and finally, (x) budding (assembly/release) inhibitors. Current knowledge, including the therapeutic potential, of these various inhibitors is discussed. In view of their potential clinical the utility, the problem of virus-drug resistance and possible strategies to circumvent this problem are also addressed. PMID:7542558

De Clercq, E

1995-01-01

365

Characteristics of Epstein-Barr virus primary infection in pediatric liver transplant recipients  

Microsoft Academic Search

Background\\/Aim: Pediatric liver transplant recipients are at high risk of Epstein-Barr virus infection. However the incidence of clinical symptoms and the graft function at the time of acute infection remains poorly documented. The aim of this study was to monitor the clinical and biochemical events associated with primary Epstein-Barr virus infection.Methods: Clinical and biological patterns associated with Epstein-Barr virus infection

Françoise Smets; Monique Bodeus; Patrick Goubau; Raymond Reding; Jean-Bernard Otte; Jean-Paul Buts; Etienne Marc Sokal

2000-01-01

366

Demographics of natural oral infection of mosquitos by venezuelan equine encephalitis virus.  

PubMed

The within-host diversity of virus populations can be drastically limited during between-host transmission, with primary infection of hosts representing a major constraint to diversity maintenance. However, there is an extreme paucity of quantitative data on the demographic changes experienced by virus populations during primary infection. Here, the multiplicity of cellular infection (MOI) and population bottlenecks were quantified during primary mosquito infection by Venezuelan equine encephalitis virus, an arbovirus causing neurological disease in humans and equids. PMID:25589654

Gutiérrez, Serafín; Thébaud, Gaël; Smith, Darci R; Kenney, Joan L; Weaver, Scott C

2015-04-01

367

Is virus coinfection a predictor of severity in children with viral respiratory infections?  

PubMed

Molecular assays have resulted in increased detection of viral respiratory infections, including virus coinfection, from children with acute respiratory infections. Yet the clinical severity of virus coinfection compared to single virus infection remains uncertain. We performed a retrospective study of children presenting with acute respiratory infections comparing clinical severity of single respiratory virus infection to virus coinfection, detected on midturbinate swabs by molecular assays. Patient characteristics and measures of clinical severity were abstracted from health records. A total of 472 virus-infected children were included, 391 with a single virus infection and 81 with virus coinfection. Virus status did not affect admission to hospital (odds ratio (OR) = 0.8; 95 % confidence interval (CI) 0.5-1.4; p 0.491) or clinical disease severity among inpatients (OR = 0.8; 95% CI 0.5-1.5; p 0.515) after adjusting for age and underlying comorbidities. However, children infected with rhinovirus/enterovirus (HRV/ENT) alone were more likely to be admitted to the hospital compared to those coinfected with HRV/ENT and at least another virus, although this was not significant in multivariable analyses (OR 0.47; 95% CI 0.22-1.0; p 0.051). In multivariable analyses, children coinfected with respiratory syncytial virus (RSV) and other viruses were significantly more likely to present with radiologically confirmed pneumonia compared to those with an isolated RSV infection (OR 3.16, 95% CI 1.07-9.34, p 0.037). Equivalent clinical severity was observed between children with single virus infection and virus coinfection, although children coinfected with RSV and other viruses presented more frequently with pneumonia than those with single RSV infection. Increased disease severity observed among children with single HRV/ENT infection requires further investigation. PMID:25596778

Asner, S A; Rose, W; Petrich, A; Richardson, S; Tran, D J

2015-03-01

368

Hepatitis B virus coinfection in human immunodeficiency virus-infected patients: A review  

PubMed Central

Hepatitis B virus (HBV) infection is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide. Due to the shared modes of transmission, coinfection with HBV and human immunodeficiency virus (HIV) is not uncommon. It is estimated that 10% of HIV-infected patients worldwide are coinfected with HBV. In areas where an HBV vaccination program is implemented, the HBV seroprevalence has declined significantly. In HIV/HBV-coinfected patients, HBV coinfection accelerates immunologic and clinical progression of HIV infection and increases the risk of hepatotoxicity when combination antiretroviral therapy (cART) is initiated, while HIV infection increases the risk of hepatitis events, cirrhosis, and end-stage liver disease related to chronic HBV infection. With the advances in antiviral therapy, concurrent, successful long-term suppression of HIV and HBV replication can be achieved in the cART era. To reduce the disease burden of HBV infection among HIV-infected patients, adoption of safe sex practices, avoidance of sharing needles and diluent, HBV vaccination and use of cART containing tenofovir disoproxil fumarate plus emtricitabine or lamivudine are the most effective approaches. However, due to HIV-related immunosuppression, using increased doses of HBV vaccine and novel approaches to HBV vaccination are needed to improve the immunogenicity of HBV vaccine among HIV-infected patients. PMID:25356024

Sun, Hsin-Yun; Sheng, Wang-Huei; Tsai, Mao-Song; Lee, Kuan-Yeh; Chang, Sui-Yuan; Hung, Chien-Ching

2014-01-01

369

Immunopathogenesis of Oropharyngeal Candidiasis in Human Immunodeficiency Virus Infection  

PubMed Central

Oropharyngeal and esophageal candidiases remain significant causes of morbidity in human immunodeficiency virus (HIV)-infected patients, despite the dramatic ability of antiretroviral therapy to reconstitute immunity. Notable advances have been achieved in understanding, at the molecular level, the relationships between the progression of HIV infection, the acquisition, maintenance, and clonality of oral candidal populations, and the emergence of antifungal resistance. However, the critical immunological defects which are responsible for the onset and maintenance of mucosal candidiasis in patients with HIV infection have not been elucidated. The devastating impact of HIV infection on mucosal Langerhans' cell and CD4+ cell populations is most probably central to the pathogenesis of mucosal candidiasis in HIV-infected patients. However, these defects may be partly compensated by preserved host defense mechanisms (calprotectin, keratinocytes, CD8+ T cells, and phagocytes) which, individually or together, may limit Candida albicans proliferation to the superficial mucosa. The availability of CD4C/HIV transgenic mice expressing HIV-1 in immune cells has provided the opportunity to devise a novel model of mucosal candidiasis that closely mimics the clinical and pathological features of candidal infection in human HIV infection. These transgenic mice allow, for the first time, a precise cause-and-effect analysis of the immunopathogenesis of mucosal candidiasis in HIV infection under controlled conditions in a small laboratory animal. PMID:15489345

de Repentigny, Louis; Lewandowski, Daniel; Jolicoeur, Paul

2004-01-01

370

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. PMID:23468505

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

2013-01-01

371

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. PMID:22232374

Samal, Jasmine; Kandpal, Manish

2012-01-01

372

[Cutaneous infection with the cytomegalovirus virus in AIDS patients].  

PubMed

Cutaneous cytomegalovirus (CMV) infection has been observed in a variety of nonspecific skin lesions. Because of this fact, its diagnosis is rare and frequently accidental. The presence of the virus has also been observed in apparently normal skin, from both a clinical and histological point of view. In this context, skin biopsy and immunohistochemistry are often the first means of diagnosis of systemic CMV infection. In 180 skin biopsies carried out on HIV patients in the Infectious and Parasitic Diseases Unit, typical histopathological findings of CMV infection in a nonspecific skin lesion were observed in only one patient. Although the patient showed no extracutaneous manifestations at this time, she died soon after this diagnosis. Because of this fact, we review the literature and discuss the difficulties and implications of the diagnosis of cutaneous CMV infection in AIDS patients. PMID:9341040

Franca, I; Poiares-Baptista, A; Pais, M J; Araújo, C; Chorão, M; Ricardo, J L; Mansinho, K

1997-01-01

373

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

374

Virus-specific antibodies in sera from patients with genital herpes simplex virus infection.  

PubMed Central

Virus-specific antibodies against a number of herpes simplex virus type 2 antigens were determined by radioimmunoprecipitation assays in sequential serum samples obtained from 12 patients with initial genital herpes simplex virus infection. The progressive appearance of antibodies to virus-specific antigens was observed; antibodies against a 130,000-molecular-weight glycoprotein complex appeared first, followed by antibodies against the major nucleocapsid polypeptide and then antibodies against a number of other viral antigens, including a polypeptide with a molecular weight of 62,000. Patients who developed a wide variety of antibodies to viral polypeptides shortly after resolution of their initial episode seemed to experience more severe initial infections and more recurrences than did those who reacted poorly with these virus-specific antigens. This was most apparent with respect to antibodies to virus-specific polypeptides with molecular weights between 30,000 and 43,000. Antibody specificity did not change during the course of follow-up regardless of whether serum samples were taken shortly before, during, or after recurrent episodes. Glycoprotein-specific antibodies were quantitated with the purified 130,000-molecular-weight glycoprotein material. No significant fluctuations in these antibody titers were observed before or after recurrences of the disease. Images PMID:7118244

Zweerink, H J; Corey, L

1982-01-01

375

Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in Canada  

PubMed Central

The purposes of this study were to determine the seroprevalence of feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) infection among cats in Canada and to identify risk factors for seropositivity. Signalment, lifestyle factors, and test results for FeLV antigen and FIV antibody were analyzed for 11 144 cats from the 10 Canadian provinces. Seroprevalence for FIV antibody was 4.3% and seroprevalence for FeLV antigen was 3.4%. Fifty-eight cats (0.5%) were seropositive for both viruses. Seroprevalence varied geographically. Factors such as age, gender, health status, and lifestyle were significantly associated with risk of FeLV and FIV seropositivity. The results suggest that cats in Canada are at risk of retrovirus infection and support current recommendations that the retrovirus status of all cats should be known. PMID:19721785

Little, Susan; Sears, William; Lachtara, Jessica; Bienzle, Dorothee

2009-01-01

376

West Nile Virus Infection of Birds, Mexico  

PubMed Central

West Nile virus (WNV) has caused disease in humans, equids, and birds at lower frequency in Mexico than in the United States. We hypothesized that the seemingly reduced virulence in Mexico was caused by attenuation of the Tabasco strain from southeastern Mexico, resulting in lower viremia than that caused by the Tecate strain from the more northern location of Baja California. During 2006–2008, we tested this hypothesis in candidate avian amplifying hosts: domestic chickens, rock pigeons, house sparrows, great-tailed grackles, and clay-colored thrushes. Only great-tailed grackles and house sparrows were competent amplifying hosts for both strains, and deaths occurred in each species. Tecate strain viremia levels were higher for thrushes. Both strains produced low-level viremia in pigeons and chickens. Our results suggest that certain avian hosts within Mexico are competent for efficient amplification of both northern and southern WNV strains and that both strains likely contribute to bird deaths. PMID:22172633

Guerrero-Sánchez, Sergio; Cuevas-Romero, Sandra; Nemeth, Nicole M.; Trujillo-Olivera, María Teresa Jesús; Worwa, Gabriella; Dupuis, Alan; Brault, Aaron C.; Kramer, Laura D.; Komar, Nicholas

2011-01-01

377

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. PMID:8786054

Torres, J R

1996-01-01

378

Association between Celiac Disease and Chronic Hepatitis C Virus Infection  

PubMed Central

Celiac disease affects the proximal small intestine and is caused by a local immune response to dietary gluten. Celiac disease usually presents with chronic diarrhea; however, presentations with elevated hepatic transaminase levels in blood or with iron-deficiency anemia have been described. Celiac disease has been reported to be associated with autoimmune liver diseases. Hepatitis C virus (HCV) can also initiate autoimmune disease process. Therefore, HCV infection and celiac disease may occur together. Here, we describe 4 cases of celiac disease associated with chronic hepatitis C. This small case series indicates that chronic HCV infection and celiac disease are not causally associated.

Garg, Ashish; Reddy, Chandrasekhar; Duseja, Ajay; Chawla, Yogesh; Dhiman, Radha K

2011-01-01

379

Acute Epstein–Barr virus infection-associated collapsing glomerulopathy  

PubMed Central

A 21-year-old woman presenting with acute Epstein–Barr virus (EBV) infection (infectious mononucleosis) was noted to have renal involvement. She had proteinuria, leukocyturia and microscopic hematuria, and 10 days after admission became nephrotic (23 g of protein per g of creatinine). Renal biopsy revealed glomerular tuft collapse, visceral epithelial cell proliferation and vacuolization consistent with collapsing glomerulopathy. She had only transient deterioration in renal function, attributed to contrast nephropathy, but after recovery remained proteinuric. Renal disease is well described in EBV infection, but collapsing glomerulopathy has not been reported previously.

Joshi, Amit; Arora, Amit; Cimbaluk, David; Dunea, George; Hart, Peter

2012-01-01

380

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. PMID:19079794

Tsunoda, Ikuo

2008-01-01

381

Cross-species infection of Deformed Wing virus poses a new threat to pollinator conservation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Here we provide the evidence that Deformed Wing Virus (DWV), one of the most prevalent and common viruses in honey bees Apis mellifera, could cause an infection in bumble bees, Bombus huntii and that the virus infection could spread over the entire body of B. huntii. Our results showed that gut of...

382

Natural and Experimental Infection of Caenorhabditis Nematodes by Novel Viruses Related to Nodaviruses  

E-print Network

Natural and Experimental Infection of Caenorhabditis Nematodes by Novel Viruses Related and host-pathogen co-evolution would combine a genetically tractable small animal with a virus capable has been limited by the lack of viruses known to infect nematodes. From wild isolates of C. elegans

Wang, David

383

Infected mosquitoes transmit the virus to birds. Birds of some species get ill and die,  

E-print Network

Infected mosquitoes transmit the virus to birds. Birds of some species get ill and die, while Virus (WNV) 3 circulates and multiplies for several days in a mosquito's blood before penetrating its salivary glands. After an in- cubation period of 10 to 14 days, an infected mosquito can transmit the virus

Kaye, Jason P.

384

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

385

Potassium Ion Channels of Chlorella Viruses Cause Rapid Depolarization of Host Cells during Infection  

Microsoft Academic Search

Previous studies have established that chlorella viruses encode K channels with different structural and functional properties. In the current study, we exploit the different sensitivities of these channels to Cs to determine if the membrane depolarization observed during virus infection is caused by the activities of these channels. Infection of Chlorella NC64A with four viruses caused rapid membrane depolarization of

Florian Frohns; Anja Kasmann; Detlef Kramer; Britta Schafer; Mario Mehmel; Ming Kang; James L. Van Etten; Sabrina Gazzarrini; Anna Moroni; Gerhard Thiel

2006-01-01

386

Identification of white spot syndrome virus (WSSV) envelope proteins involved in shrimp infection  

Microsoft Academic Search

White spot syndrome virus (WSSV) is a major shrimp pathogen causing large economic losses. In an attempt to identify the envelope proteins involved in virus infection, antisera against six WSSV envelope proteins were used in neutralization assays conducted in vivo. The results showed that the virus infection could be significantly delayed or neutralized by antibodies against three WSSV envelope proteins

Wenlin Wu; Lei Wang; Xiaobo Zhang

2005-01-01

387

A Mathematical Model for Virus Infection in a System of Interacting Computers  

E-print Network

A Mathematical Model for Virus Infection in a System of Interacting Computers J. L´opez Gondar & R are explored and enlightened in this paper. 1. Introduction The infection of computers by virtual viruses of virtual viruses in a system of interacting computers could be compared with a disease transmitted

Cipolatti, Rolci

388

Subclinical Highly Pathogenic Avian Influenza Virus Infection among Vaccinated Chickens, China  

PubMed Central

Subclinical infection of vaccinated chickens with a highly pathogenic avian influenza A(H5N2) virus was identified through routine surveillance in China. Investigation suggested that the virus has evolved into multiple genotypes. To better control transmission of the virus, we recommend a strengthened program of education, biosecurity, rapid diagnostics, surveillance, and elimination of infected poultry. PMID:25418710

Ma, Qing-Xia; Jiang, Wen-Ming; Liu, Shuo; Wang, Su-Chun; Zhuang, Qing-Ye; Hou, Guang-Yu; Liu, Xiang-Ming; Sui, Zheng-Hong

2014-01-01

389

A SAP30 Complex Inhibits IFN-b Expression in Rift Valley Fever Virus Infected Cells  

E-print Network

A SAP30 Complex Inhibits IFN-b Expression in Rift Valley Fever Virus Infected Cells Nicolas Le May1, Institut Pasteur, Paris, France Rift Valley fever virus (RVFV) nonstructural protein NSs acts as the major Valley Fever Virus infected cells. PLoS Pathog 4(1): e13. doi:10.1371/journal.ppat.0040013 Introduction

Paris-Sud XI, Université de

390

Viruses infecting marine picoplancton encode functional potassium ion channels.  

PubMed

Phycodnaviruses are dsDNA viruses, which infect algae. Their large genomes encode many gene products, like small K(+) channels, with homologs in prokaryotes and eukaryotes. Screening for K(+) channels revealed their abundance in viruses from fresh-water habitats. Recent sequencing of viruses from marine algae or from salt water in Antarctica revealed sequences with the predicted characteristics of K(+) channels but with some unexpected features. Two genes encode either 78 or 79 amino acid proteins, which are the smallest known K(+) channels. Also of interest is an unusual sequence in the canonical ?-helixes in K(+) channels. Structural prediction algorithms indicate that the new channels have the conserved ?-helix folds but the algorithms failed to identify the expected transmembrane domains flanking the K(+) channel pores. In spite of these unexpected properties electophysiological studies confirmed that the new proteins are functional K(+) channels. PMID:25441713

Siotto, Fenja; Martin, Corinna; Rauh, Oliver; Van Etten, James L; Schroeder, Indra; Moroni, Anna; Thiel, Gerhard

2014-10-01

391

Gene silencing: a therapeutic approach to combat influenza virus infections.  

PubMed

Selective gene silencing technologies such as RNA interference (RNAi) and nucleic acid enzymes have shown therapeutic potential for treating viral infections. Influenza virus is one of the major public health concerns around the world and its management is challenging due to a rapid increase in antiviral resistance. Influenza vaccine also has its limitations due to the emergence of new strains that may escape the immunity developed by the previous year's vaccine. Antiviral drugs are the primary mode of prevention and control against a pandemic and there is an urgency to develop novel antiviral strategies against influenza virus. In this review, we discuss the potential utility of several gene silencing mechanisms and their prophylactic and therapeutic potential against the influenza virus. PMID:25598342

Khanna, Madhu; Saxena, Latika; Rajput, Roopali; Kumar, Binod; Prasad, Rajendra

2015-01-01

392

Systems biology unravels interferon responses to respiratory virus infections  

PubMed Central

Interferon production is an important defence against viral replication and its activation is an attractive therapeutic target. However, it has long been known that viruses perpetually evolve a multitude of strategies to evade these host immune responses. In recent years there has been an explosion of information on virus-induced alterations of the host immune response that have resulted from data-rich omics technologies. Unravelling how these systems interact and determining the overall outcome of the host response to viral infection will play an important role in future treatment and vaccine development. In this review we focus primarily on the interferon pathway and its regulation as well as mechanisms by which respiratory RNA viruses interfere with its signalling capacity. PMID:24600511

Kroeker, Andrea L; Coombs, Kevin M

2014-01-01

393

Infections  

MedlinePLUS

... Infections Warts West Nile Virus What Is "PANS"? Whooping Cough (Pertussis) Yersiniosis Ear Infections Can Chronic Ear Infections ... Scarlet Fever Sinusitis Strep Throat Tuberculosis Walking Pneumonia Whooping Cough (Pertussis) Medical Tests A Directory of Medical Tests ...

394

Emergence of CD4 Independence Envelopes and Astrocyte Infection in R5 Simian-Human Immunodeficiency Virus Model of Encephalitis  

PubMed Central

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection in the central nervous system (CNS) is characterized by replication in macrophages or brain microglia that express low levels of the CD4 receptor and is the cause of HIV-associated dementia and related cognitive and motor disorders that affect 20 to 30% of treatment-naive patients with AIDS. Independent viral envelope evolution in the brain has been reported, with the need for robust replication in resident CD4low cells, as well as CD4-negative cells, such as astrocytes, proposed as a major selective pressure. We previously reported giant-cell encephalitis in subtype B and C R5 simian-human immunodeficiency virus (SHIV)-infected macaques (SHIV-induced encephalitis [SHIVE]) that experienced very high chronic viral loads and progressed rapidly to AIDS, with varying degrees of macrophage or microglia infection and activation of these immune cells, as well as astrocytes, in the CNS. In this study, we characterized envelopes (Env) amplified from the brains of subtype B and C R5 SHIVE macaques. We obtained data in support of an association between severe neuropathological changes, robust macrophage and microglia infection, and evolution to CD4 independence. Moreover, the degree of Env CD4 independence appeared to correlate with the extent of astrocyte infection in vivo. These findings further our knowledge of the CNS viral population phenotypes that are associated with the severity of HIV/SHIV-induced neurological injury and improve our understanding of the mechanism of HIV-1 cellular tropism and persistence in the brain. IMPORTANCE Human immunodeficiency virus type 1 (HIV-1) infection of astrocytes in the brain has been suggested to be important in HIV persistence and neuropathogenesis but has not been definitively demonstrated in an animal model of HIV-induced encephalitis (HIVE). Here, we describe a new nonhuman primate (NHP) model of R5 simian-human immunodeficiency virus (SHIV)-induced encephalitis (SHIVE) with several classical HIVE features that include astrocyte infection. We further show an association between severe neuropathological changes, robust resident microglia infection, and evolution to CD4 independence of viruses in the central nervous system (CNS), with expansion to infection of truly CD4-negative cells in vivo. These findings support the use of the R5 SHIVE models to study the contribution of the HIV envelope and viral clades to neurovirulence and residual virus replication in the CNS, providing information that should guide efforts to eradicate HIV from the body. PMID:24829360

Zhuang, Ke; Leda, Ana Rachel; Tsai, Lily; Knight, Heather; Harbison, Carole; Gettie, Agegnehu; Blanchard, James; Westmoreland, Susan

2014-01-01

395

BOVINE VIRAL DIARRHEA VIRUS PERSISTENT INFECTIONS IN BEEF BREEDING HERDS: UTILIZATION OF IMMUNOHISTOCHEMISTRY AND ANTIGEN CAPTIVE ELISA ON EAR NOTCHES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bovine viral diarrhea virus (BVDV) infections represent significant disease manifestations in cattle. Persistently infected (PI) cattle resulting from fetal infections are considered the major reservoir of virus for susceptible cattle. Beef cattle in stocker and feedlot operations are often where ...

396

Protracted viremia during acute sporadic hepatitis E virus infection  

Microsoft Academic Search

Background\\/Aims: Hepatitis E virus (HEV) is associated with epidemic and sporadic hepatitis in developing countries. The disease is largely self-limited with no long-term sequelae. The source of HEV for maintenance of the disease in an endemic area is unknown. This study investigated the occurrence and duration of viremia in patients with acute sporadic HEV infection. Methods: In 26 of 37

Santosh Kumar Nanda; Israrul Haque Ansari; Subrat Kumar Acharya; Shahid Jameel; Subrat Kumar Panda

1995-01-01

397

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

398

Characterization of Citrus Tristeza Virus Subgenomic RNAs in Infected Tissue  

Microsoft Academic Search

Citrus tristeza virus (CTV) specific RNAs extracted from infected citrus tissue were analyzed by Northern blot hybridization. RNAs were characterized by size and identified using cDNA probes specific to nine open reading frames (ORFs) identified by the analysis of sequence obtained from cDNA clones of the T36 isolate of CTV. Sequence specific cDNA probes identified the genomic RNA as well

Mark E. Hilf; Alexander V. Karasev; Hanumantha R. Pappu; David J. Gumpf; Charles L. Niblett; Stephen M. Garnsey

1995-01-01

399

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

400

Virus Competition for Shedding and Tumor Formation Over Time in Marek's Disease Virus Dual-infected Chickens  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study was designed to determine what effect multiple virulent Marek’s disease viruses have on each other over time during dual-infection. Serotype 1 viruses able to be differentiated were administered either simultaneously or with a short (24 hours) or long (13 days) interval. Virus frequency ...

401

Small RNA profiles from virus-infected fresh market vegetables.  

PubMed

Functional small RNAs, such as short interfering RNAs (siRNAs) and microRNAs (miRNAs), exist in freshly consumed fruits and vegetables. These siRNAs can be derived either from endogenous sequences or from viruses that infect them. Symptomatic tomatoes, watermelons, zucchini, and onions were purchased from grocery stores and investigated by small RNA sequencing. By aligning the obtained small RNA sequences to sequences of known viruses, four different viruses were identified as infecting these fruits and vegetables. Many of these virally derived small RNAs along with endogenous small RNAs were found to be highly complementary to human genes. However, the established history of safe consumption of these vegetables suggests that this sequence homology has little biological relevance. By extension, these results provide evidence for the safe use by humans and animals of genetically engineered crops using RNA-based suppression technologies, especially vegetable crops with virus resistance conferred by expression of siRNAs or miRNAs derived from viral sequences. PMID:25389086

Frizzi, Alessandra; Zhang, Yuanji; Kao, John; Hagen, Charles; Huang, Shihshieh

2014-12-10

402

A Bacteriophage-Related Chimeric Marine Virus Infecting Abalone  

PubMed Central

Marine viruses shape microbial communities with the most genetic diversity in the sea by multiple genetic exchanges and infect multiple marine organisms. Here we provide proof from experimental infection that abalone shriveling syndrome-associated virus (AbSV) can cause abalone shriveling syndrome. This malady produces histological necrosis and abnormally modified macromolecules (hemocyanin and ferritin). The AbSV genome is a 34.952-kilobase circular double-stranded DNA, containing putative genes with similarity to bacteriophages, eukaryotic viruses, bacteria and endosymbionts. Of the 28 predicted open reading frames (ORFs), eight ORF-encoded proteins have identifiable functional homologues. The 4 ORF products correspond to a predicted terminase large subunit and an endonuclease in bacteriophage, and both an integrase and an exonuclease from bacteria. The other four proteins are homologous to an endosymbiont-derived helicase, primase, single-stranded binding (SSB) protein, and thymidylate kinase, individually. Additionally, AbSV exhibits a common gene arrangement similar to the majority of bacteriophages. Unique to AbSV, the viral genome also contains genes associated with bacterial outer membrane proteins and may lack the structural protein-encoding ORFs. Genomic characterization of AbSV indicates that it may represent a transitional form of microbial evolution from viruses to bacteria. PMID:21079776

Zhuang, Jun; Cai, Guiqin; Lin, Qiying; Wu, Zujian; Xie, Lianhui

2010-01-01

403

Tembusu virus infection in Cherry Valley ducks: the effect of age at infection.  

PubMed

Three groups of Cherry Valley ducks at 5 day, 2 week and 5 week of age were intranasally infected with the WFCL strain of Tembusu virus (TMUV) to investigate the effect of host age on the outcome of TMUV infection. For each age group, clinical signs, gross and microscopic lesions, viral copy numbers in tissues and serum neutralizing antibody titers were recorded. Age-related differences in the resistance to TMUV infection were observed with younger ducks being more susceptible. Some ducks infected at 5 day and 2 week of age developed severe clinical signs, including severe neurological dysfunction and death. However, subclinical signs and no mortality were observed in ducks infected at 5 week of age. A decline in the severity of gross and microscopic lesions was observed as ducks mature. Systemic infections were established in the three age groups post challenge. Higher viral copy numbers in the tissues, especially in vital organs such as the brain and the heart, were developed in the ducks infected at 5 day of age than older ducks, correlating with the severity of clinical signs and lesions in the tissues. Furthermore, ducks infected at 5 week of age developed significantly higher serum neutralizing antibody titers than ducks infected at 5 day of age as determined by serum neutralization test. Therefore, age-related differences in the resistance to TMUV infection should be considered when studying the pathogenicity, pathogenesis, formulation of the vaccination and therapy strategies of TMUV infection in ducks. PMID:24210575

Sun, X Y; Diao, Y X; Wang, J; Liu, X; Lu, A L; Zhang, L; Ge, P P; Hao, D M

2014-01-10

404

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

405

Influence of Hydrogel Substrate on Cell Growth and Virus Infection  

NASA Astrophysics Data System (ADS)

The interaction of cells with their extracellular matrix is of great importance when cells adapt to their environment. The purpose of this thesis is to design substrates with controllable properties and to study cellular interaction on these substrates. Firstly, enzymatically cross-linked gelatin hydrogels with different elastic modulus were prepared. Then, we studied the condition of cell growth and virus infection on these hydrogels as a followed-up. In the first part of the study, we made enzymatically cross-linked gelatin hydrogels with five different elastic modulus. As a parameter of stiffness, elastic modulus varies from 2.4 KPa to 7.5 KPa based on which hydrogels are graded from soft to hard. In the second part, we studied the growth of rabbit kidney cells cultured on hydrogels of different stiffness. Growth curves of the cells were made to study the abilities of soft and hard hydrogels to support cell proliferation. Result shows that cell proliferation rate differs when using hydrogel substrates of different stiffness as substrates. In the third part of this thesis, we infected rabbit kidney cells with pseudorabies virus for a period of time. And confocal fluorescence microscopy was used to investigate the influence of hydrogels with different elastic modulus on infectivity of the virus.

Yang, Fan

406

Bacterial prostatitis in patients infected with the human immunodeficiency virus.  

PubMed

Bacterial prostatitis was diagnosed in 17 of 209 human immunodeficiency virus-infected men hospitalized from October 1985 to October 1987. A history of urogenital disease was found in 13 of 17 patients. Clinical signs of prostatitis were present in 16 of 17 patients, including fever in 13, urinary symptoms in 11 and tender prostate on rectal palpation in 7. Bacteriuria was found in 14 of the 17 patients. Prostatic ultrasound examination showed an abscess in 11 of 16 patients studied. Prostatitis was diagnosed at autopsy in 1 patient. Within 6 weeks after onset of antimicrobial therapy 9 of 13 patients were cured and 4 of 13 did not respond to therapy. Among the 7 patients followed for more than 2 months after the end of antimicrobial therapy 5 had relapse. The prevalence of bacterial prostatitis among human immunodeficiency virus-infected patients increased from 3 per cent in asymptomatic human immunodeficiency virus-infected patients to 14 per cent in patients with the acquired immunodeficiency syndrome. PMID:2643725

Leport, C; Rousseau, F; Perronne, C; Salmon, D; Joerg, A; Vilde, J L

1989-02-01

407

Incident hepatitis C virus in women with human immunodeficiency virus infection.  

PubMed

Individuals infected with human immunodeficiency virus type 1 (HIV-1) are frequently coinfected with hepatitis C virus (HCV). Acute HCV infection is often asymptomatic and poorly understood. We conducted a historical prospective study of HCV antibody and viremia in plasma samples obtained during 1994-1999 from a cohort of initially HIV-1-infected, HCV-uninfected women and from HIV-1-HCV-uninfected women. Twenty-two (1.5%) of 1517 experienced seroconversion. Of these, 14 (64%) truly acquired a new infection as assessed by enzyme immunoassay response and new-onset viremia. The incidence rate in HIV-1-infected women was 2.7 cases per 1000 person-years; it was 3.3 cases per 1000 person-years in HIV-1-seronegative women (relative risk, 1.21; P=.75). Acquisition of HCV was associated with any history of drug use (P<.01). Five of 12 viremic, seroconverting individuals cleared viremia. Incident HCV infection among HIV-1-infected and HIV-1-uninfected women was low. It was linked to drug use and commonly resolved. PMID:14583870

Augenbraun, M; Goedert, J J; Thomas, D; Feldman, J; Seaberg, E C; French, A L; Robison, E; Nowicki, M; Terrault, N

2003-11-15

408

Mavericks, a novel class of giant transposable elements widespread in eukary-otes and related to DNA viruses  

E-print Network

in the fungi Glomus intraradices and Phakopsora pachyrhizi and in several single-celled eukaryotes bacteriophages and diverse eukaryotic double-stranded DNA viruses, including a DNA polymerase B homolog, Feschotte, C´edric, Mavericks, a novel class of giant transposable elements widespread in eukaryotes

Feschotte, Cedric

409

Effective etanercept treatment for psoriatic arthritis complicating concomitant human immunodeficiency virus and hepatitis C virus infection.  

PubMed

High levels of tumor necrosis factor-alpha (TNF-alpha) are associated with hepatitis C virus (HCV) infection and all stages of human immunodeficiency virus (HIV) infection. TNF-alpha may have a role in both the pathogenesis and the response to treatment of these chronic viral diseases. We describe a 42-year-old HIV/HCV coinfected hemophiliac man who developed psoriasis and severe psoriatic arthritis not responding to combination treatment with methotrexate and cyclosporin A. Treatment with etanercept 25 mg twice weekly was followed by remission of the joint inflammation and improvement of the exanthem. This is the first report of anti-TNF-alpha treatment for rheumatic complications in a patient with both HIV and HCV infection. PMID:17552060

Linardaki, Garifallia; Katsarou, Olga; Ioannidou, Panagiota; Karafoulidou, Anastasia; Boki, Kyriaki

2007-06-01

410

Index cluster study of dengue virus infection in Nicaragua.  

PubMed

Traditional study designs do not identify acute asymptomatic or pre-symptomatic dengue virus (DENV) infections, thus limiting our understanding of immunologic and viral factors that modulate infection outcome. In the 2006 and 2007 dengue seasons, we conducted a pilot index cluster study in Managua, Nicaragua, in which 442 persons living within 50 meters of 22 index cases identified through an ongoing pediatric cohort study were evaluated for DENV infection. Post-enrollment and pre-enrollment DENV infections were confirmed in 12 (2.7%) and 19 (4.3%) contacts, respectively. Five (42%) post-enrollment infections were asymptomatic, and DENV-2 was identified in 9 (75%) infections. Phylogenetic analysis with full-length DENV genomic sequence from contacts, index cases, and cohort dengue cases indicated focal transmission and infection outside the local area. We demonstrate the feasibility of identification of acute asymptomatic and pre-symptomatic cases in urban Latin America, the first report of such a study in the Americas, and identify age and concomitant immunity to DENV of contacts as a key factor in index cluster study design. PMID:20810839

Reyes, Miguel; Mercado, Juan Carlos; Standish, Katherine; Matute, Juan Carlos; Ortega, Oscar; Moraga, Berman; Avilés, William; Henn, Matthew R; Balmaseda, Angel; Kuan, Guillermina; Harris, Eva

2010-09-01

411

Host Transcription Profiles upon Primary Respiratory Syncytial Virus Infection? †  

PubMed Central

Respiratory syncytial virus (RSV) is a common cause of severe lower respiratory tract infection in children. Severe RSV disease is related to an inappropriate immune response to RSV resulting in enhanced lung pathology which is influenced by host genetic factors. To gain insight into the early pathways of the pathogenesis of and immune response to RSV infection, we determined the transcription profiles of lungs and lymph nodes on days 1 and 3 after infection of mice. Primary RSV infection resulted in a rapid but transient innate, proinflammatory response, as exemplified by the induction of a large number of type I interferon-regulated genes and chemokine genes, genes involved in inflammation, and genes involved in antigen processing. Interestingly, this response is much stronger on day 1 than on day 3 after infection, indicating that the strong transcriptional response in the lung precedes the peak of viral replication. Surprisingly, the set of down-regulated genes was small and none of these genes displayed strong down-regulation. Responses in the lung-draining lymph nodes were much less prominent than lung responses and are suggestive of NK cell activation. Our data indicate that at time points prior to the peak of viral replication and influx of inflammatory cells, the local lung response, measured at the transcriptional level, has already dampened down. The processes and pathways induced shortly after RSV infection can now be used for the selection of candidate genes for human genetic studies of children with severe RSV infection. PMID:17376894

Janssen, Riny; Pennings, Jeroen; Hodemaekers, Hennie; Buisman, Annemarie; van Oosten, Marijke; de Rond, Lia; Öztürk, Kemal; Dormans, Jan; Kimman, Tjeerd; Hoebee, Barbara

2007-01-01

412

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

413

Molecular Ecology and Natural History of Simian Foamy Virus Infection in Wild-Living Chimpanzees  

Microsoft Academic Search

Identifying microbial pathogens with zoonotic potential in wild-living primates can be important to human health, as evidenced by human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2) and Ebola virus. Simian foamy viruses (SFVs) are ancient retroviruses that infect Old and New World monkeys and apes. Although not known to cause disease, these viruses are of public health interest

Weimin Liu; Michael Worobey; Yingying Li; Brandon F. Keele; Frederic Bibollet-Ruche; Yuanyuan Guo; Paul A. Goepfert; Mario L. Santiago; Jean-Bosco N. Ndjango; Cecile Neel; Stephen L. Clifford; Crickette Sanz; Shadrack Kamenya; Michael L. Wilson; Anne E. Pusey; Nicole Gross-Camp; Christophe Boesch; Vince Smith; Koichiro Zamma; Michael A. Huffman; John C. Mitani; David P. Watts; Martine Peeters; George M. Shaw; William M. Switzer; Paul M. Sharp; Beatrice H. Hahn

2008-01-01

414

Autonomic Nervous Dysfunction in Hamsters Infected with West Nile Virus  

PubMed Central

Clinical studies and case reports clearly document that West Nile virus (WNV) can cause respiratory and gastrointestinal (GI) complications. Other functions controlled by the autonomic nervous system may also be directly affected by WNV, such as bladder and cardiac functions. To investigate how WNV can cause autonomic dysfunctions, we focused on the cardiac and GI dysfunctions of rodents infected with WNV. Infected hamsters had distension of the stomach and intestines at day 9 after viral challenge. GI motility was detected by a dye retention assay; phenol red dye was retained more in the stomachs of infected hamsters as compared to sham-infected hamsters. The amplitudes of electromygraphs (EMGs) of intestinal muscles were significantly reduced. Myenteric neurons that innervate the intestines, in addition to neurons in the brain stem, were identified to be infected with WNV. These data suggest that infected neurons controlling autonomic function were the cause of GI dysfunction in WNV-infected hamsters. Using radiotelemetry to record electrocardiograms and to measure heart rate variability (HRV), a well-accepted readout for autonomic function, we determined that HRV and autonomic function were suppressed in WNV-infected hamsters. Cardiac histopathology was observed at day 9 only in the right atrium, which was coincident with WNV staining. A subset of WNV infected cells was identified among cells with hyperplarization-activated cyclic nucleotide-gated potassium channel 4 (HCN4) as a marker for cells in the sinoatrial (SA) and atrioventricular (AV) nodes. The unique contribution of this study is the discovery that WNV infection of hamsters can lead to autonomic dysfunction as determined by reduced HRV and reduced EMG amplitudes of the GI tract. These data may model autonomic dysfunction of the human West Nile neurological disease. PMID:21573009

Wang, Hong; Siddharthan, Venkatraman; Hall, Jeffery O.; Morrey, John D.

2011-01-01

415

Viral spread in the presence of neutralizing antibody: mechanisms of persistence in foamy virus infection.  

PubMed Central

Several viruses were categorized on the basis of their ability to spread from cell to contiguous cell and form plaques in the presence of antiviral antibody. Herpes simplex virus, cytomegalovirus, and vaccinia, measles, and foamy viruses were able to spread in the presence of neutralizing antibody, whereas coxsackievirus, encephalomyocarditis virus, vesicular stomatitis virus, mumps virus, and simian virus 5 failed to spread. A detailed study of one of these virus groups (simian foamy viruses) suggested that the ability of these viruses to spread from cell to cell in the presence of antiviral antibody, the failure of antiviral antibody and complement to lyse infected cells, and the poor induction and relative resistance of these viruses to the antiviral action of interferon contribute to the persistent nature of this infection. PMID:185150

Hooks, J J; Burns, W; Hayashi, K; Geis, S; Notkins, A L

1976-01-01

416

Feline immunodeficiency virus: quantification in peripheral blood mononuclear cells and isolation from plasma of infected cats  

Microsoft Academic Search

Summary The titer of feline immunodeficiency virus in peripheral blood mononuclear cells (PBMC) and the presence of infectious virus in plasma was investigated over 20 week period in 8 experimentally infected cats, 3 uninfected cats and 2 naturally infected cats by end point dilution cultures using a feline T-lymphoblastoid cell line (MYA-1). FIV was isolated from PBMC of all infected

Joanne Meers; W. F. Robinson; G. M. del Fierro; M. A. Scoones; M. A. Lawson

1992-01-01

417

Recombination Every Day: Abundant Recombination in a Virus during a Single MultiCellular Host Infection  

Microsoft Academic Search

Viral recombination can dramatically impact evolution and epidemiology. In viruses, the recombination rate depends on the frequency of genetic exchange between different viral genomes within an infected host cell and on the frequency at which such co-infections occur. While the recombination rate has been recently evaluated in experimentally co-infected cell cultures for several viruses, direct quantification at the most biologically

Remy Froissart; Denis Roze; Marilyne Uzest; Lionel Galibert; Stephane Blanc; Yannis Michalakis

2005-01-01

418

Establishment of a new cell line from the heart of giant grouper, Epinephelus lanceolatus (Bloch), and its application in toxicology and virus susceptibility.  

PubMed

A new marine fish cell line, derived from the heart of giant grouper, Epinephelus lanceolatus (Bloch), was established and characterized. The cell line was designated as ELGH and subcultured with more than 60 passages. The ELGH cells were mainly composed of fibroblast-like cells and multiplied well in Leibovitz's L-15 medium supplemented with 10% foetal bovine serum (FBS) at 28 °C. Chromosome analysis indicated that the modal chromosome number was 48. The fluorescent signals were detected in ELGH when transfected with green fluorescent protein reporter plasmids. The 50% cytotoxic concentration (CC50 ) of the extracellular products (ECPs) from Streptococcus iniae and Vibrio alginolyticus E333 on ELGH cells was 60.02 and 12.49 ?g mL(-1), respectively. Moreover, the ELGH cells showed susceptibility to Singapore grouper iridovirus (SGIV), but not to soft-shelled turtle iridovirus (STIV), red-spotted grouper nervous necrosis virus (RGNNV) and spring viremia of carp virus (SVCV), which was demonstrated by the presence of a severe cytopathic effect (CPE) and increased viral titres. In addition, electron microscopy observation showed that abundant virus particles were present in the infected cells. Taken together, our data above provided the potential utility of ELGH cells for transgenic and genetic manipulation, as well as cytotoxicity testing and virus pathogenesis. PMID:24372271

Guo, C Y; Huang, Y H; Wei, S N; Ouyang, Z L; Yan, Y; Huang, X H; Qin, Q W

2015-02-01

419

Pattern of SIVagm infection in patas monkeys suggests that host adaptation to simian immunodeficiency virus infection may result in resistance to infection and virus extinction.  

PubMed

Patas monkeys were not reported to carry species?specific simian immunodeficiency virus (SIV), but cross?species transmission of SIVagm to patas monkeys occurred in the wild. We report that patas monkeys share immunophenotypic features with natural hosts of SIV; that is, low levels of CD4+ T cells and low CCR5 expression on CD4+ T cells. In 1 patas monkey with undetectable levels of CD4+ T cells, experimental exposure to SIVagm did not result in infection. The other experimentally infected patas monkeys showed an infection pattern similar to SIV infection in natural hosts. Thus, down?regulation of CD4 and CCR5 expression on CD4+ T cells may effectively control human immunodeficiency virus acquisition and result in SIV extinction. PMID:20887227

Apetrei, Cristian; Gaufin, Thaidra; Gautam, Rajeev; Vinton, Carol; Hirsch, Vanessa; Lewis, Mark; Brenchley, Jason; Pandrea, Ivona

2010-11-01

420

Hepatitis E Virus infection in HIV-infected patients with elevated serum transaminases levels  

PubMed Central

Increases in aminotransferases levels are frequently encountered in HIV-positive patients and often remain unexplained. The role in this setting and natural history of hepatitis E in HIV-infected patients are unknown. The aim of the study was to assess HEV infection in HIV-infected patients attending a Parisian hospital, with a current or previous cryptogenic hepatitis.191 plasma samples collected from 108 HIV-infected patients with elevated aminotransferases levels were retrospectively tested for the presence of hepatitis E virus (HEV) infection markers: anti-HEV IgM antibodies, anti-HEV IgG antibodies, anti-HEV IgG avidity index and plasma HEV RNA.One acute infection, documented by positive tests for anti-HEV IgM antibody, low anti-HEV IgG avidity index and plasma HEV RNA (genotype 3e), and three past infections were diagnosed, without any observed case of persistent infection. The acute hepatitis was benign and resolved spontaneously within two weeks. This infection was probably contracted locally. Acute HEV hepatitis can occur in HIV-infected patients but rarely explains cryptogenic hepatitis, at least in an urban HIV population, regardless geographic origin and CD4 counts. PMID:21496215

2011-01-01

421

Host Immune Status and Response to Hepatitis E Virus Infection  

PubMed Central

SUMMARY Hepatitis E virus (HEV), identified over 30 years ago, remains a serious threat to life, health, and productivity in developing countries where access to clean water is limited. Recognition that HEV also circulates as a zoonotic and food-borne pathogen in developed countries is more recent. Even without treatment, most cases of HEV-related acute viral hepatitis (with or without jaundice) resolve within 1 to 2 months. However, HEV sometimes leads to acute liver failure, chronic infection, or extrahepatic symptoms. The mechanisms of pathogenesis appear to be substantially immune mediated. This review covers the epidemiology of HEV infection worldwide, the humoral and cellular immune responses to HEV, and the persistence and protection of antibodies produced in response to both natural infection and vaccines. We focus on the contributions of altered immune states (associated with pregnancy, human immunodeficiency virus [HIV], and immunosuppressive agents used in cancer and transplant medicine) to the elevated risks of chronic infection (in immunosuppressed/immunocompromised patients) and acute liver failure and mortality (among pregnant women). We conclude by discussing outstanding questions about the immune response to HEV and interactions with hormones and comorbid conditions. These questions take on heightened importance now that a vaccine is available. PMID:24396140

Krain, Lisa J.; Nelson, Kenrad E.

2014-01-01

422

Autochthonous Dobrava-Belgrade virus infection in Eastern Germany.  

PubMed

A 21-year-old male patient from Borna, Saxony, in Eastern Germany, suffered from acute kidney injury (AKI) and symptoms typical for a hantavirus infection. These symptoms included nausea, vomiting, abdominal pain, diarrhea, and acute renal failure. Serological investigations by indirect IgM and IgG in-house ELISAs, commercial immunofluorescence and line assays, as well as chemiluminescence focus reduction neutralization assay confirmed an acute Dobrava-Belgrade virus (DOBV) infection of the patient. Serological and RT-PCR analyses of striped field mouse (Apodemus agrarius) trapped in a neighboring region of the residence of the patient identified an infection by DOBV, genotype Kurkino. This is the first report of an autochthonous DOBV infection in a German patient living far from the known endemic region in the north of the country. This finding has implications for the awareness of physicians in areas which are not recognized as hantavirus endemic regions but where the reservoir host of the virus is present. PMID:24495905

Rasche, Franz Maximilian; Schmidt, Sabrina; Kretzschmar, Christian; Mertens, Marc; Thiel, Jörg; Groschup, Martin H; Schlegel, Mathias; Mayer, Christof; Lindner, Tom H; Schiekofer, Stephan; Ulrich, Rainer G

2015-02-01

423

Sharka: how do plants respond to Plum pox virus infection?  

PubMed

Plum pox virus (PPV), the causal agent of sharka disease, is one of the most studied plant viruses, and major advances in detection techniques, genome characterization and organization, gene expression, transmission, and the description of candidate genes involved in PPV resistance have been described. However, information concerning the plant response to PPV infection is very scarce. In this review, we provide an updated summary of the research carried out to date in order to elucidate how plants cope with PPV infection and their response at different levels, including the physiological, biochemical, proteomic, and genetic levels. Knowledge about how plants respond to PPV infection can contribute to the development of new strategies to cope with this disease. Due to the fact that PPV induces an oxidative stress in plants, the bio-fortification of the antioxidative defences, by classical or biotechnological approaches, would be a useful tool to cope with PPV infection. Nevertheless, there are still some gaps in knowledge related to PPV-plant interaction that remain to be filled, such as the effect of PPV on the hormonal profile of the plant or on the plant metabolome. PMID:25336685

Clemente-Moreno, María J; Hernández, José A; Diaz-Vivancos, Pedro

2015-01-01

424

Avian influenza virus infection dynamics in shorebird hosts.  

PubMed

To gain insight into avian influenza virus (AIV) transmission, exposure, and maintenance patterns in shorebirds at Delaware Bay during spring migration, we examined temporal AIV prevalence trends in four Charadriiformes species with the use of serial cross-sectional data from 2000 through 2008 and generalized linear and additive models. Prevalence of AIV in Ruddy Turnstones (Arenaria interpres morinella) increased after arrival, peaked in mid-late May, and decreased prior to departure. Antibody prevalence also increased over this period; together, these results suggested local infection and recovery prior to departure. Red Knots (Calidris canutus rufa), Sanderlings (Calidris alba), and Laughing Gulls (Leucophaeus atricilla) were rarely infected, but dynamic changes in antibody prevalence differed among species. In Red Knots, declining antibody prevalence over the stopover period suggested AIV exposure prior to arrival at Delaware Bay with limited infection at this site. Antibody prevalence was consistently high in Laughing Gulls and low in Sanderlings. Both viral prevalence and antibody prevalence in Sanderlings varied directly with those in turnstones, suggesting virus spillover to Sanderlings. Results indicate that, although hundreds of thousands of birds concentrate at Delaware Bay during spring, dynamics of AIV infection differ among species, perhaps due to differences in susceptibility, potential for contact with AIV at this site, or prior exposure. Additionally, Ruddy Turnstones possibly act as a local AIV amplifying host rather than a reservoir. PMID:22493108

Maxted, Angela M; Luttrell, M Page; Goekjian, Virginia H; Brown, Justin D; Niles, Lawrence J; Dey, Amanda D; Kalasz, Kevin S; Swayne, David E; Stallknecht, David E

2012-04-01

425

Antigen-specific B-cell receptor sensitizes B cells to infection by influenza virus  

E-print Network

Influenza A virus-specific B lymphocytes and the antibodies they produce protect against infection. However, the outcome of interactions between an influenza haemagglutinin-specific B cell via its receptor (BCR) and virus ...

Dougan, Stephanie K.

426

SITES OF IN VIVO REPLICATION OF BOVINE LEUKEMIA VIRUS IN EXPERIMENTALLY INFECTED CATTLE  

E-print Network

SITES OF IN VIVO REPLICATION OF BOVINE LEUKEMIA VIRUS IN EXPERIMENTALLY INFECTED CATTLE M.J. VAN of the initial events following the experimental inoculation of cal- ves with bovine leukemia virus. The results

Paris-Sud XI, Université de

427

Platforms for exploring host-pathogen interactions in hepatitis C virus infection  

E-print Network

Afflicting almost 200 million worldwide, hepatitis C virus (HCV) mounts a chronic infection of liver hepatocytes that causes substantial morbidity and mortality. An understanding of host-virus interactions will drive the ...

Trehan, Kartik

2012-01-01

428

Indigenous hepatitis E virus infection in England: More common than it seems  

Microsoft Academic Search

BackgroundIndigenous hepatitis E virus (HEV) is increasingly diagnosed in England due to a better awareness and understanding of the virus. However, the true burden of infection and therefore its implication to public health remains undefined.

Samreen Ijaz; Andrew J. Vyse; Dilys Morgan; Richard G. Pebody; Richard S. Tedder; David Brown

2009-01-01

429

Mucosal disease induced in cattle persistently infected with bovine viral diarrhea virus by antigenically different cytopathic virus  

Microsoft Academic Search

Summary.  ?Four cattle persistently infected with non-cytopathic (NCP) bovine viral diarrhea (BVD) virus were challenged with cytopathic\\u000a (CP) BVD virus that was antigenically different from the persistent virus. Two of the animals were injected with dexamethasone\\u000a (DM) and then challenged. They developed mucosal disease on days 21 and 33 post-challenge. CP-BVD viruses were isolated from\\u000a their lymph nodes but not from

H. Sentsui; T. Nishimori; R. Kirisawa; A. Morooka

2001-01-01

430

[Modern immunological and clinical determinants of virus dengue infection].  

PubMed

The growing problem of widespread viral infections is a challenge for modern medicine. Emerging reports of dengue virus infections in Europe create a new epidemic problem. The virus responsible for causing the symptoms of the disease is transmitted by mosquitoes. Over 50% of the world's population lives in areas where the risk of dengue feveris high. In total, according to WHO, infected with dengue is 2.4 million people and outbreaks of endemic diseases are present in 100 countries that threaten the 2.5 billion population. There are four serotypes of dengue virus, which belong to the family Flaviviridae and the type of Flavirus. Serotypes are known as DENV-1, DENV-2, DENV-3 and DENV-4. Contact each of the serotypes of the virus causes long-lasting resistance to the other, and each of them is responsible for the induction of disease epidemics, including severe cases. In the first stage of the disease should seek to replace lost fluids and electrolytes. Because of the elevated body temperature is recommended to administer paracetamol formulations and the use of cold compresses. Contraindicated is the use of aspirin and non-steroidal anti-inflammatory drugs. In severe forms of dengue patients absolutely should be hospitalized and treatment in the intensive care centers. In the treatment of shock, it is recommended that the administration of isotonic crystalloid fluids at 5-10 ml/kg/hr. under the control of hematocrit and fill peripheral microcirculation. The administration of blood products for the large current is required to control bleeding. Dengue vaccine containing DEN-DEN chimeras is still at the stage of preclinical studies. PMID:25546995

P?usa, Tadeusz

2014-11-01

431

Crystal structure of a nematode-infecting virus  

PubMed Central

Orsay, the first virus discovered to naturally infect Caenorhabditis elegans or any nematode, has a bipartite, positive-sense RNA genome. Sequence analyses show that Orsay is related to nodaviruses, but molecular characterizations of Orsay reveal several unique features, such as the expression of a capsid–? fusion protein and the use of an ATG-independent mechanism for translation initiation. Here we report the crystal structure of an Orsay virus-like particle assembled from recombinant capsid protein (CP). Orsay capsid has a T = 3 icosahedral symmetry with 60 trimeric surface spikes. Each CP can be divided into three regions: an N-terminal arm that forms an extended protein interaction network at the capsid interior, an S domain with a jelly-roll, ?-barrel fold forming the continuous capsid, and a P domain that forms surface spike projections. The structure of the Orsay S domain is best aligned to T = 3 plant RNA viruses but exhibits substantial differences compared with the insect-infecting alphanodaviruses, which also lack the P domain in their CPs. The Orsay P domain is remotely related to the P1 domain in calicivirus and hepatitis E virus, suggesting a possible evolutionary relationship. Removing the N-terminal arm produced a slightly expanded capsid with fewer nucleic acids packaged, suggesting that the arm is important for capsid stability and genome packaging. Because C. elegans-Orsay serves as a highly tractable model for studying viral pathogenesis, our results should provide a valuable structural framework for further studies of Orsay replication and infection. PMID:25136116

Guo, Yusong R.; Hryc, Corey F.; Jakana, Joanita; Jiang, Hongbing; Wang, David; Chiu, Wah; Zhong, Weiwei; Tao, Yizhi J.

2014-01-01

432

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

433

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. PMID:21274371

Tsubota, Akihito; Fujise, Kiyotaka; Namiki, Yoshihisa; Tada, Norio

2011-01-01

434

Experimental Infections of Wild Birds with West Nile Virus  

PubMed Central

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

2014-01-01

435

The live attenuated bovine viral diarrhea virus components of a multi-valent vaccine confer protection against fetal infection  

Microsoft Academic Search

Fetal infection with bovine virus diarrhea virus (BVDV) causes severe economic loss and virus spread in cattle. This study investigated the ability of modified live BVDV I and II components of a commercially available modified live virus (MLV) vaccine (Breed-Back FP 10™, Boehringer Ingelheim Vetmedica Inc.) to prevent fetal infection and abortion, and therefore the birth of persistently infected animals.

Ferenc Kovács; Tibor Magyar; Carol Rinehart; Knut Elbers; Kathy Schlesinger; William Charles Ohnesorge

2003-01-01

436

Persistent Infection of Rats with Haemorrhagic Fever with Renal Syndrome Virus and their Antibody Responses  

Microsoft Academic Search

SUMMARY Newborn (within 24 h after birth), 1-week-old and 6-week-old (adult) rats were inoculated with a Hantaan-related virus (B-l) and attempts were made to isolate the virus from various organs. Virus-specific antigens were detected in various organs of newborn rats. Moreover virus could be isolated from almost all their organs even 25 weeks after infection. In contrast, in rats infected

OSAMU TANISHITA; YOSHIYUKI TAKAHASHI; YOSHINOBU OKUNO; MANABU TAMURA; HIDEO ASADA; JOSE R. DANTAS; TAKAHISA YAMANOUCHI; KAYOKO DOMAE; TAKESHI KURATA; KOICHI YAMANISHI

1986-01-01

437

Concurrent Bovine Virus Diarrhea and Bovine Papular Stomatitis Infection in a Calf  

PubMed Central

A case of concurrent infection with the viruses of bovine virus diarrhea and papular stomatitis in a calf is reported. The difficulties posed by such situations are described and the criteria used for diagnosis outlined. The two diseases are reviewed briefly and the possible mechanisms whereby bovine virus diarrhea virus is suspected of facilitating infection by other agents are discussed. ImagesFigure 1.Figure 2.Figure 3.Figure 4. PMID:7459795

Bohac, J. G.; Yates, W. D. G.

1980-01-01

438

Virological features of hepatitis C virus infection in hemodialysis patients.  

PubMed

The clinical and epidemiological relevance of circulating antibodies to hepatitis C virus (HCV) in hemodialysis patients is uncertain, since clinical signs of infection are often mild or absent, with alanine aminotransferase (ALT) values that are virtually always normal, and liver biopsies are only rarely performed. Determination of HCV RNA in serum is therefore critical for distinguishing chronic HCV infection from previous exposure to the virus. We studied HCV viremia by reverse transcription polymerase chain reaction (RT-PCR) in the 5'-noncoding region of the viral genome in 77 dialysis patients who were screened for anti-HCV by a second-generation enzyme-linked immunosorbent assay (the enzyme immunoassay II; Ortho HCV, 2nd generation, Ortho Diagnostic Systems Raritan, N.J.) and a second-generation recombinant immunoblot assay (Chiron Corporation and Ortho Diagnostic Systems) and prospectively evaluated for ALT elevations over a period of 5 years. Of 77 patients tested, 29 (38%) had active infection as shown by a positive PCR assay result, and of these, 26 were anti-HCV positive. Although a good correlation was found between circulating anti-HCV and HCV RNA in serum, 10 (28%) of 36 anti-HCV-positive patients were HCV RNA negative by PCR, suggesting either low levels of viremia or past exposure to HCV and subsequent recovery. On the other hand, 3 (7.3%) of 41 anti-HCV-negative patients had HCV RNA in their sera, indicating seronegative HCV infection. The ALT level had no predictive value for HCV infection, because it was repeatedly normal in 18 (62%) of 29 viremic patients. HCV genotyping was also performed and indicated that all four known genotypes of HCV were present in our group. In conclusion, serological assays are reliable for detecting exposure to HCV in hemodialysis patients; however, direct identification of the viral genome is required to document current infection. PMID:7505292

Silini, E; Bono, F; Cerino, A; Piazza, V; Solcia, E; Mondelli, M U

1993-11-01

439

Human genes involved in hepatitis B virus infection  

PubMed Central

Persistent hepatitis B virus (HBV) infection is a significant public health problem because it is a major cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma (HCC). Roughly one-third of the world population has been infected with HBV and there are about 350 million (5%-6%) persistent carriers. HBV causes 80% of all liver cancer cases and is the second most important carcinogen, after smoking tobacco. There is an approximate 90% risk of becoming a persistent carrier following perinatal infection in infants born to e antigen positive carrier mothers and a 30% risk in pre-school children. Only 5%-10% of adults become persistent carriers following infection. Of individuals persistently infected with HBV, 10%-30% will develop liver cirrhosis and HCC. These highly variable outcomes in both clearance rates and disease outcomes in persistently infected individuals cannot be fully explained by differences in immunological, viral or environmental factors. Thus, differences in host genetic factors may affect the natural history of hepatitis B. PMID:24976707

Zeng, Zheng

2014-01-01

440

Immunologic, metabolic and genetic factors in hepatitis C virus infection  

PubMed Central

The mechanisms that regulate disease progression during hepatitis C virus (HCV) infection and the response to treatment are not clearly identified. Numerous studies have demonstrated that a strong host immune response against HCV favors HCV clearance. In addition, genetic factors and metabolic machinery, particularly cholesterol modulation, are involved in HCV infection. It is likely that the interplay between all of these factors contributes to the outcome of HCV infection. In recent years, the world has experienced its largest epidemic of obesity. Mexico and the United States are the leading sufferers from this epidemic at the global level. Obesity is associated with the development of numerous pathologies including hypercholesterolemia which is one of the eight most important risk factors for mortality in Mexico. This may be related to the course of HCV infection in this population. Here, we focus on the urgent need to study the progression of HCV infection in relation to ethnic characteristics. Discoveries are discussed that hold promise in identifying immune, metabolic and genetic factors that, in conjunction, could be therapeutic targets or predictors of the progression of HCV infection. PMID:24707127

Fierro, Nora A; Gonzalez-Aldaco, Karina; Torres-Valadez, Rafael; Martinez-Lopez, Erika; Roman, Sonia; Panduro, Arturo

2014-01-01