Flaviviruses

The 2 -C-methyl-substituted ribonucleosides 2 -C-methyladenosine and -guanosine were also found to inhibit the replication of flaviviruses other than HCV, such as bovine viral diarrhea virus (BVDV), yellow fever virus, and West Nile virus (Mighaccio et al. 2003). Other 2 -C-methylribonucleosides such as P-D-2 -deoxy-2 -lluoro-2 -C-methylcytidine (PSl-6130), however, showed little if any activity against BVDV, West Nile virus, or yellow fever virus (Stuyver et al. 2006). 

In support of this, several recent studies have evaluated the clinical outcomes observed in flavivirus-infected patients that carry the CCR5A32 allele. One group... 

Flaviviruses Yeiiow fever virus Spherical particles 40 nm in diameter with an inner core surrounded by an adherent lipid envelope The virus is spread to humans by mosquito bites the liver is the main target necrosis of hepatocytes leads to jaundice and fever... 

HCV is a small enveloped single-stranded RNA virus belonging to the Flaviviridae family and Hepacivirus genus [12]. Other Flaviviridae members include the flaviviruses such as yellow fever virus, and pestiviruses, which are responsible, for example, for bovine viral diarrhea [13]. The most closely related virus identified to date is GBV-B, which infects the tamarind, a new world monkey. GBV-B has also been tentatively classified as a Hepacivirus... 

Khan, A.M., and Wright, P.J. (1987) Detection of flavivirus RNA in infected cells using photobiotin-labelled hybridization probes./. Virol. Meth. 15, 121-130. 

CDC Case Definition A mosquito-borne viral illness characterized by acute onset and constitutional symptoms followed by a brief remission and a recurrence of fever, hepatitis, albuminuria, and symptoms and, in some instances, renal failure, shock, and generalized hemorrhages. Laboratory criteria for diagnosis is (1) fourfold or greater rise in yellow fever antibody titer in a patient who has no history of recent yellow fever vaccination and cross-reactions to other flaviviruses have been excluded or (2) demonstration of yellow fever virus, antigen, or genome in tissue, blood, or other body fluid. 

Despite the protective effect of NO against various viral infections, workers in several studies have shown a harmful role of NO in many systems. NO seems to play a part in the development of pneumonia caused by influenza virus [128], in the pathogenesis in mice of tick-borne encephalitis flavivirus infection [131], and in worsening the course of the murine myocarditis caused by coxsackievirus B3 [132]. In addition, pneumonia in mice induced by herpes simplex virus type 1 could be suppressed by the inhibitor of iNOS [133]. The issue of whether NO acts as an inhibitor of viral replication or as a harmful agent, therefore, remains unanswered. This issue is particularly evident in HIV-1 infection, since NO seems to act as a double-edged sword in the pathogenesis of HIV-1. 

Flavin mononucleotide (FMN), 25 796 cofactor regeneration using, 3 673 Flaviviruses, 3 137-138 Flavones, microwave-assisted synthesis of, 16 575... 

Flavivirus is a genus of the family Flaviviridae composed of nearly 70 arthropod-borne viruses that cause important human diseases, such as yellow fever virus (YFV), DENV, West Nile virus (WNV), and Japanese encephalitis virus (JEV). They cause a variety of diseases including fever, encephalitis, and hemorrhagic fever. In particular, DENV has reemerged in recent years as an increasingly important public health threat affecting more than 100 countries worldwide, with nearly 50 million infections each year and over 2.5 billion people at risk [81]. 

Flaviviruses are included among the enveloped viruses recently reported as dependent on cell surface HS to efficiently initiate cell infection. An involvement of HS during attachment and entry through its binding to the virion envelope glycoprotein E was initially demonstrated for DENV [82] and then extended to YFV [83], tick-borne encephalitis virus (TBEV) [84], and Murray Valley encephalitis virus (MVEV) [85], as well as to hepatitis C virus (HCV), a member of the Hepacivirus genus of Flaviviridae [86]. 

Interestingly, the antiviral activity of HS mimetics against flaviviruses was also demonstrated in vivo. Two sulfated galactomannans extracted from seeds of Mimosa scabrella and Leucaena leucocephala, named BRS and LLS, respectively, protected mice against intraperitoneal infection with YFV [91]. More recently, the oligosaccharide PI-88 was assayed in vitro and in murine models of flavivirus infection. This low molecular weight compound did not show in vitro effectiveness but ameliorated disease in JEV and DENV-2 infected mice,... 

Flavivirus Yellow fever Tropical Africa, South America Mosquito 3-6... 

Ribavirin, a nucleoside analog, is recommended for postexposure prophylaxis for Lassa and possibly for other arenaviruses, but only if signs of infection are present. Ribavirin has no efficacy against filovirus or flavivirus infection (Borio et al., 2002). 

Fold Flavivirus glycoprotein domain 1 is an antiparallel (3 barrel that is quite different from the viral capsid jelly roll... 

Flavivirus Tick-home encephalitis virus Verebrates/Insect... 

Fig. 1. Illustration of two morphologies of enveloped viruses (not drawn to scale). (A) The surface proteins of influenzavirus project like spikes or cylinders from the virus envelope. (B) The surface proteins of flaviviruses lie flat against the virus envelope.

Although there are mechanistic differences between retroviruses, paramyxoviruses, and the orthomyxovirus influenza, the viruses discussed to this point have definite structural and functional similarities including spikelike, trimeric native structures and the presence of coiled coils in their fusion-active subunits. The flaviviruses and alphaviruses, however, appear to be another class of enveloped viruses entirely. Flaviviruses include yellow fever. West Nile virus. Dengue virus, and tick-borne encephalitis virus (TBEV). Alphaviruses, of the togavirus family, include... 

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