Flaviviridae Infections: Infections with viruses of the family FLAVIVIRIDAE.Flaviviridae: A family of RNA viruses, many of which cause disease in humans and domestic animals. There are three genera FLAVIVIRUS; PESTIVIRUS; and HEPACIVIRUS, as well as several unassigned species.Flavivirus: A genus of FLAVIVIRIDAE containing several subgroups and many species. Most are arboviruses transmitted by mosquitoes or ticks. The type species is YELLOW FEVER VIRUS.Diarrhea Viruses, Bovine Viral: A group of viruses in the genus PESTIVIRUS, causing diarrhea, fever, oral ulcerations, hemorrhagic syndrome, and various necrotic lesions among cattle and other domestic animals. The two species (genotypes), BVDV-1 and BVDV-2 , exhibit antigenic and pathological differences. The historical designation, BVDV, consisted of both (then unrecognized) genotypes.GB virus A: A species of virus (unassigned to a genus) in the family FLAVIVIRIDAE, that have been identified in at least six species of New World monkeys. They do not cause HEPATITIS in the host or other susceptible species.Flavivirus Infections: Infections with viruses of the genus FLAVIVIRUS, family FLAVIVIRIDAE.Pestivirus: A genus of FLAVIVIRIDAE, also known as mucosal disease virus group, which is not arthropod-borne. Transmission is by direct and indirect contact, and by transplacental and congenital transmission. Species include BORDER DISEASE VIRUS, bovine viral diarrhea virus (DIARRHEA VIRUS, BOVINE VIRAL), and CLASSICAL SWINE FEVER VIRUS.Saguinus: A genus in the subfamily CALLITRICHINAE consisting of 12 species and found in Panama as well as South America. Species seen most frequently in the literature are S. oedipus (cotton-top marmoset), S. nigricollis, and S. fusicollis.West Nile virus: A species of FLAVIVIRUS, one of the Japanese encephalitis virus group (ENCEPHALITIS VIRUSES, JAPANESE). It can infect birds and mammals. In humans, it is seen most frequently in Africa, Asia, and Europe presenting as a silent infection or undifferentiated fever (WEST NILE FEVER). The virus appeared in North America for the first time in 1999. It is transmitted mainly by CULEX spp mosquitoes which feed primarily on birds, but it can also be carried by the Asian Tiger mosquito, AEDES albopictus, which feeds mainly on mammals.Encephalitis Virus, St. Louis: A species of FLAVIVIRUS, one of the Japanese encephalitis virus group (ENCEPHALITIS VIRUSES, JAPANESE), which is the etiologic agent of ST. LOUIS ENCEPHALITIS in the United States, the Caribbean, and Central and South America.Viral Nonstructural Proteins: Proteins encoded by a VIRAL GENOME that are produced in the organisms they infect, but not packaged into the VIRUS PARTICLES. Some of these proteins may play roles within the infected cell during VIRUS REPLICATION or act in regulation of virus replication or VIRUS ASSEMBLY.GB virus C: A species of virus (unassigned to a genus) in the family FLAVIVIRIDAE. It is genetically heterogeneous, of human origin, and transmitted by blood or blood products. Despite its alternate name (Hepatitis G virus), its pathogenicity remains controversial.Classical swine fever virus: A species of the PESTIVIRUS genus causing exceedingly contagious and fatal hemorrhagic disease of swine.Nucleoside-Triphosphatase: An enzyme which catalyzes the hydrolysis of nucleoside triphosphates to nucleoside diphosphates. It may also catalyze the hydrolysis of nucleotide triphosphates, diphosphates, thiamine diphosphates and FAD. The nucleoside triphosphate phosphohydrolases I and II are subtypes of the enzyme which are found mostly in viruses.Encephalitis, St. Louis: A viral encephalitis caused by the St. Louis encephalitis virus (ENCEPHALITIS VIRUS, ST. LOUIS), a FLAVIVIRUS. It is transmitted to humans and other vertebrates primarily by mosquitoes of the genus CULEX. The primary animal vectors are wild birds and the disorder is endemic to the midwestern and southeastern United States. Infections may be limited to an influenza-like illness or present as an ASEPTIC MENINGITIS or ENCEPHALITIS. Clinical manifestations of the encephalitic presentation may include SEIZURES, lethargy, MYOCLONUS, focal neurologic signs, COMA, and DEATH. (From Adams et al., Principles of Neurology, 6th ed, p750)Culex: A genus of mosquitoes (CULICIDAE) commonly found in tropical regions. Species of this genus are vectors for ST. LOUIS ENCEPHALITIS as well as many other diseases of man and domestic and wild animals.Dengue Virus: A species of the genus FLAVIVIRUS which causes an acute febrile and sometimes hemorrhagic disease in man. Dengue is mosquito-borne and four serotypes are known.RNA Helicases: A family of proteins that promote unwinding of RNA during splicing and translation.Hepatitis, Viral, Animal: INFLAMMATION of the LIVER in animals due to viral infection.Arboviruses: Arthropod-borne viruses. A non-taxonomic designation for viruses that can replicate in both vertebrate hosts and arthropod vectors. Included are some members of the following families: ARENAVIRIDAE; BUNYAVIRIDAE; REOVIRIDAE; TOGAVIRIDAE; and FLAVIVIRIDAE. (From Dictionary of Microbiology and Molecular Biology, 2nd ed)Encephalitis Virus, Japanese: A species of FLAVIVIRUS, one of the Japanese encephalitis virus group (ENCEPHALITIS VIRUSES, JAPANESE), which is the etiological agent of Japanese encephalitis found in Asia, southeast Asia, and the Indian subcontinent.Genome, Viral: The complete genetic complement contained in a DNA or RNA molecule in a virus.Yellow fever virus: The type species of the FLAVIVIRUS genus. Principal vector transmission to humans is by AEDES spp. mosquitoes.RNA, Viral: Ribonucleic acid that makes up the genetic material of viruses.West Nile Fever: A mosquito-borne viral illness caused by the WEST NILE VIRUS, a FLAVIVIRUS and endemic to regions of Africa, Asia, and Europe. Common clinical features include HEADACHE; FEVER; maculopapular rash; gastrointestinal symptoms; and lymphadenopathy. MENINGITIS; ENCEPHALITIS; and MYELITIS may also occur. The disease may occasionally be fatal or leave survivors with residual neurologic deficits. (From Joynt, Clinical Neurology, 1996, Ch26, p13; Lancet 1998 Sep 5;352(9130):767-71)Arbovirus Infections: Infections caused by arthropod-borne viruses, general or unspecified.RNA Replicase: An enzyme that catalyses RNA-template-directed extension of the 3'- end of an RNA strand by one nucleotide at a time, and can initiate a chain de novo. (Enzyme Nomenclature, 1992, p293)Hepacivirus: A genus of FLAVIVIRIDAE causing parenterally-transmitted HEPATITIS C which is associated with transfusions and drug abuse. Hepatitis C virus is the type species.Culicidae: A family of the order DIPTERA that comprises the mosquitoes. The larval stages are aquatic, and the adults can be recognized by the characteristic WINGS, ANIMAL venation, the scales along the wing veins, and the long proboscis. Many species are of particular medical importance.Hepatitis, Viral, Human: INFLAMMATION of the LIVER in humans due to infection by VIRUSES. There are several significant types of human viral hepatitis with infection caused by enteric-transmission (HEPATITIS A; HEPATITIS E) or blood transfusion (HEPATITIS B; HEPATITIS C; and HEPATITIS D).Bovine Virus Diarrhea-Mucosal Disease: Acute disease of cattle caused by the bovine viral diarrhea viruses (DIARRHEA VIRUSES, BOVINE VIRAL). Often mouth ulcerations are the only sign but fever, diarrhea, drop in milk yield, and loss of appetite are also seen. Severity of clinical disease varies and is strain dependent. Outbreaks are characterized by low morbidity and high mortality.Host-Pathogen Interactions: The interactions between a host and a pathogen, usually resulting in disease.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Virus Replication: The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.Insect Vectors: Insects that transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.Disease Vectors: Invertebrates or non-human vertebrates which transmit infective organisms from one host to another.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Serine Endopeptidases: Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.Aedes: A genus of mosquitoes (CULICIDAE) frequently found in tropical and subtropical regions. YELLOW FEVER and DENGUE are two of the diseases that can be transmitted by species of this genus.Antiviral Agents: Agents used in the prophylaxis or therapy of VIRUS DISEASES. Some of the ways they may act include preventing viral replication by inhibiting viral DNA polymerase; binding to specific cell-surface receptors and inhibiting viral penetration or uncoating; inhibiting viral protein synthesis; or blocking late stages of virus assembly.Viral Envelope Proteins: Layers of protein which surround the capsid in animal viruses with tubular nucleocapsids. The envelope consists of an inner layer of lipids and virus specified proteins also called membrane or matrix proteins. The outer layer consists of one or more types of morphological subunits called peplomers which project from the viral envelope; this layer always consists of glycoproteins.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Bovine virus diarrhea: Bovine Viral Diarrhea (BVD) or Bovine Viral Diarrhoea (UK English), and previously referred to as Bovine Virus Diarrhoea (BVD), is a significant economic disease of cattle which is endemic in the majority of countries throughout the world. The causative agent, bovine viral diarrhea virus (BVDV) is a member of the Pestivirus genus of the family Flaviviridae.West Nile virus in the United States: The West Nile virus quickly spread across the United States after the first reported cases in Queens, New York in 1999. The virus is believed to have entered in an infected bird or mosquito, although there is no clear evidence.East St. Louis and Suburban Railway: The East St. Louis and Suburban Railway was an interurban railroad that operated in Illinois.NS3 (HCV): Nonstructural protein 3 (NS3), also known as p-70, is a viral nonstructural protein that is 70 kDa cleavage product of the hepatitis C virus polyprotein. It acts as a serine protease.Classical swine fever: Classical swine fever (CSF) or hog cholera (also sometimes called pig plague based on the German word Schweinepest) is a highly contagious disease of swine (Old World and New World pigs).Saint Louis University School of Public HealthCulex quinquefasciatus: Culex quinquefasciatus (earlier known as Culex fatigans), the southern house mosquito, is a medium-sized mosquito found in tropical and subtropical regions of the world. It is the vector of Wuchereria bancrofti, avian malaria, and arboviruses including St.Armitage–Doll multistage model of carcinogenesis: The Armitage–Doll model is a statistical model of carcinogenesis, proposed in 1954 by Peter Armitage and Richard Doll, which suggested that a sequence of multiple distinct genetic events preceded the onset of cancer. The original paper has recently been reprinted with a set of commentary articles.List of mystery diseases: A mystery disease is a disease that has not yet been identified. Reasons for lack of identification of etiology include lack of professional interest, difficult access, and lack of resources, in addition to being unknown to medicine.List of West Nile virus outbreaks: *United States: From 1999 through 2001, the CDC confirmed 149 West Nile virus infections, including 18 deaths. In 2002, a total of 4,156 cases were reported, including 284 fatalities.PSI-6130Canine hepacivirus: Canine hepacivirus is a single strand RNA virus of the genus Hepacivirus.Kapoor A, Simmonds P, Gerold G, Qaisar N, Jain K, Henriquez JA, Firth C, Hirschberg DL, Rice CM, Shields S, Lipkin WI (2011) Characterization of a canine homolog of hepatitis C virus.Psorophora howardiiBranching order of bacterial phyla (Gupta, 2001): There are several models of the Branching order of bacterial phyla, one of these was proposed in 2001 by Gupta based on conserved indels or protein, termed "protein signatures", an alternative approach to molecular phylogeny. Some problematic exceptions and conflicts are present to these conserved indels, however, they are in agreement with several groupings of classes and phyla.Ditch: A ditch is a small to moderate depression created to channel water. A ditch can be used for drainage, to drain water from low-lying areas, alongside roadways or fields, or to channel water from a more distant source for plant irrigation.Coles PhillipsProlyl endopeptidase: Prolyl endopeptidase (PE) also known as prolyl oligopeptidase or post-proline cleaving enzyme is an enzyme that in humans is encoded by the PREP gene.Aedes aegyptiAntiviral drug: Antiviral drugs are a class of medication used specifically for treating viral infections. Like antibiotics for bacteria, specific antivirals are used for specific viruses.Pseudotyping: Pseudotyping is the process of producing viruses or viral vectors in combination with foreign viral envelope proteins. The result is a pseudotyped virus particle.Beef cattle: Beef cattle are cattle raised for meat production (as distinguished from dairy cattle, used for milk production). The meat of adult cattle is known as beef.
(1/92) Perspectives for the treatment of infections with Flaviviridae.
The family Flaviviridae contains three genera: Hepacivirus, Flavivirus, and Pestivirus. Worldwide, more than 170 million people are chronically infected with Hepatitis C virus and are at risk of developing cirrhosis and/or liver cancer. In addition, infections with arthropod-borne flaviviruses (such as dengue fever, Japanese encephalitis, tick-borne encephalitis, St. Louis encephalitis, Murray Valley encephalitis, West Nile, and yellow fever viruses) are emerging throughout the world. The pestiviruses have a serious impact on livestock. Unfortunately, no specific antiviral therapy is available for the treatment or the prevention of infections with members of the Flaviviridae. Ongoing research has identified possible targets for inhibition, including binding of the virus to the cell, uptake of the virus into the cell, the internal ribosome entry site of hepaciviruses and pestiviruses, the capping mechanism of flaviviruses, the viral proteases, the viral RNA-dependent RNA polymerase, and the viral helicase. In light of recent developments, the prevalence of infections caused by these viruses, the disease spectrum, and the impact of infections, different strategies that could be pursued to specifically inhibit viral targets and animal models that are available to study the pathogenesis and antiviral strategies are reviewed. (+info)
(2/92) Standardization of immunoglobulin M capture enzyme-linked immunosorbent assays for routine diagnosis of arboviral infections.
Immunoglobulin M antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA) is a rapid and versatile diagnostic method that readily permits the combination of multiple assays. Test consolidation is especially important for arthropod-borne viruses (arboviruses) which belong to at least three virus families: the Togaviridae, Flaviviridae, and Bunyaviridae. Using prototype viruses from each of these families and a panel of well-characterized human sera, we have evaluated and standardized a combined MAC-ELISA capable of identifying virus infections caused by members of each virus family. Furthermore, by grouping antigens geographically and utilizing known serological cross-reactivities, we have reduced the number of antigens necessary for testing, while maintaining adequate detection sensitivity. We have determined that a 1:400 serum dilution is most appropriate for screening antiviral antibody, using a positive-to-negative ratio of >/=2.0 as a positive cutoff value. With a blind-coded human serum panel, this combined MAC-ELISA was shown to have test sensitivity and specificity that correlated well with those of other serological techniques. (+info)
(3/92) Prevalence of and risk factors for hepatitis G (HGV) infection in haemodialysis patients: a multicentre study.
BACKGROUND: Hepatitis G virus (HGV) or GB-virus type C (GBV-C) is, like hepatitis C, a blood-borne virus and a member of the family of flaviviridae. HGV is distributed globally and is present in the volunteer blood donor population. Thus, for epidemiological reasons, HGV is of interest in haemodialysis patients, who are at risk of parenterally transmitted infections. The aim of the present investigation was to assess the prevalence of HGV by antibody testing and HGV-RNA determination by PCR. METHODS: The study was performed in haemodialysis units of the Patienten-Heim-Versorgung, an organization of haemodialysis units throughout Germany. A total of 2796 out of 3042 patients (92%) from 43 haemodialysis units were enrolled prospectively in the trial. Liver function tests were performed and epidemiologic data were obtained to evaluate risk factors for HGV in haemodialysis patients. RESULTS: Antibodies against HGV were detected in 485 patients (17.5%). Viraemia was seen in 380 out of 1935 patients tested (19.6%). Fifty-eight patients (3.0%) were positive for both antibodies and HGV-RNA. Using a standard questionnaire in 1717 out of the 2786 patients, it was found that more than five blood transfusions increased the risk of HGV infection significantly (P<0.05). There was no association found between HGV infection and the length of time on haemodialysis. CONCLUSION: HGV is common in German haemodialysis patients but, in contrast to other parenterally transmitted viruses, there is no further risk for new infections during haemodialysis, except for patients who have received several blood transfusions. (+info)
(4/92) A study on pathogenicity of hepatitis G virus.
AIM: To study the pathogenicity of hepatitis G virus (HGV) and observe the genesis and pathological process of hepatitis G. METHODS: HGV-RNA in serum was detected by RT-PCR assay. The immunohistochemical assays of liver tissue were performed with HGV monocoloned antibody (McAb) expressed from the region of HGV NS5 nucleic acid sequence. The clinical and pathological data of 52 patients with hepatitis G were discussed. In animal experiment, the Chinese Rhesus monkeys were infected with the serum of a patient with HGV infection. And the dynamic changes in serology and liver histology of animals were observed. RESULTS: One hundred and fifty-four patients with HGV-RNA positive were selected from 1552 patients with various kinds of hepatitis. Of 154 patients with HGV infection, 52 were infected with HGV only, which accounted for 33.8 (52/154) and 102 with positive HGV-RNA were super-infected with other hepatitis viruses, which accounted for 66.2 (102/154). The clinical and pathological observation showed that the acute and chronic hepatitis could be induced by HGV. The slight abnormality of transaminases ALT and AST in serum of monkeys lasted nearly 12 months and histological results showed a series of pathological changes. CONCLUSION: HGV is a hepatotropic virus and has pathogenicty. (+info)
(5/92) Lack of both Fas ligand and perforin protects from flavivirus-mediated encephalitis in mice.
The mechanism by which encephalitic flaviviruses enter the brain to inflict a life-threatening encephalomyelitis in a small percentage of infected individuals is obscure. We investigated this issue in a mouse model for flavivirus encephalitis in which the virus was administered to 6-week-old animals by the intravenous route, analogous to the portal of entry in natural infections, using a virus dose in the range experienced following the bite of an infectious mosquito. In this model, infection with 0.1 to 10(5) PFU of virus gave mortality in approximately 50% of animals despite low or undetectable virus growth in extraneural tissues. We show that the cytolytic effector functions play a crucial role in invasion of the encephalitic flavivirus into the brain. Mice deficient in either the granule exocytosis- or Fas-mediated pathway of cytotoxicity showed delayed and reduced mortality. Mice deficient in both cytotoxic effector functions were resistant to a low-dose peripheral infection with the neurotropic virus. (+info)
(6/92) Evidence for probable sexual transmission of the hepatitis g virus.
A cross-sectional epidemiology study evaluated the role of sexual activity and sexually transmitted diseases (STDs) in the transmission of hepatitis G virus (HGV/GBV-C) and other hepatitis virus infections in 944 subjects. There was a statistically significant higher prevalence of HGV/GBV-C, hepatitis B virus, and hepatitis C virus exposure in the STD clinic group (i.e., subjects who were currently seeking treatment for an STD) compared with the group who never had received treatment for an STD. In a comparison of the subjects with an STD versus those without an STD, the prevalence of HGV/GBV-C was 11.3% versus 4.9%, on the basis of polymerase chain reaction (PCR) results alone, and 36.6% versus 8.8%, when results of PCR and enzyme-linked immunosorbent assay were combined. Sexual activity and, possibly, the presence of an STD increases the risk of HGB/GBV-C transmission. (+info)
(7/92) Liver histology in co-infection of hepatitis C virus (HCV) and hepatitis G virus (HGV).
As little is known about liver histology in the co-infection of hepatitis C virus (HCV) and hepatitis G virus (HGV), HGV RNA was investigated in 46 blood donors with hepatitis C, 22 of them with liver biopsy: co-infection HCV / HGV (n = 6) and HCV isolated infection (n = 16). Besides staging and grading of inflammation at portal, peri-portal and lobular areas (Brazilian Consensus), the fibrosis progression index was also calculated. All patients had no symptoms or signs of liver disease and prevalence of HGV / HCV co-infection was 15.2%. Most patients had mild liver disease and fibrosis progression index, calculated only in patients with known duration of infection, was 0.110 for co-infection and 0.130 for isolated HCV infection, characterizing these patients as "slow fibrosers". No statistical differences could be found between the groups, although a lesser degree of inflammation was always present in co-infection. In conclusion co-infection HCV / HGV does not induce a more aggressive liver disease, supporting the hypothesis that HGV is not pathogenic. (+info)
(8/92) High prevalence of hepatitis G virus infection in Hodgkin's disease and B-cell lymphoproliferative disorders: absence of correlation with hepatitis C virus infection.
BACKGROUND AND OBJECTIVES: During the last decade an epidemiological association between hepatitis C virus (HCV) and B-cell lymphoproliferative disorders (B-LPD) has been reported; the same association has not been observed for Hodgkin's disease (HD). Hepatitis G virus (HGV) shares genetic and biological features with HCV, thus it might also be involved in lymphomagenesis. DESIGN AND METHODS: The aim of this study was to compare the prevalence of HCV and HGV infection in patients at diagnosis of B-LPD or HD. RESULTS: We tested 227 consecutive untransfused patients (127 with B-LPD and 100 with HD) and 110 healthy controls. The prevalence of HCV infection was significantly higher in B-LPD patients than in controls (17.3% vs. 1.8%, p<0.002 ), whereas it was the same in HD patients as in controls. In contrast, the prevalence of HGV was significantly higher in patients, both those with B-LPD (7.8% vs. 0.9%, p<0.03) and those with HD (13% vs. 0.9%, p<0.002), than in controls. Among the various B-LPD tested, HGV infection was more frequent in B-NHL (11.5%). INTERPRETATION AND CONCLUSIONS: Our data support the hypothesis that HGV infection may play a role in lymphomagenesis and that this role is different and separate from that of HCV. (+info)