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Serologic evidence of flavivirus infection in bats in the Yucatan Peninsula of Mexico.

We captured 140 bats of seven species in Merida City in the Yucatan Peninsula of Mexico in 2010. Serum was collected from each bat and assayed by plaque reduction neutralization test (PRNT) using six flaviviruses: West Nile virus, St. Louis encephalitis virus, and dengue viruses 1-4. Flavivirus-specific antibodies were detected in 26 bats (19%). The antibody-positive bats belonged to three species: the Pallas's long-tongued bat (Glossophaga soricina), Jamaican fruit bat (Artibeus jamaicensis), and great fruit-eating bat (Artibeus lituratus), and their flavivirus antibody prevalences were 33%, …

Antagonism of the complement component C4 by flavivirus nonstructural protein NS1.

The complement system plays an essential protective role in the initial defense against many microorganisms. Flavivirus NS1 is a secreted nonstructural glycoprotein that accumulates in blood, is displayed on the surface of infected cells, and has been hypothesized to have immune evasion functions. Herein, we demonstrate that dengue virus (DENV), West Nile virus (WNV), and yellow fever virus (YFV) NS1 attenuate classical and lectin pathway activation by directly interacting with C4. Binding of NS1 to C4 reduced C4b deposition and C3 convertase (C4b2a) activity. Although NS1 bound C4b, it lacked…

Structure and functionality in flavivirus NS-proteins: perspectives for drug design.

Flaviviridae are small enveloped viruses hosting a positive-sense single-stranded RNA genome. Besides yellow fever virus, a landmark case in the history of virology, members of the Flavivirus genus, such as West Nile virus and dengue virus, are increasingly gaining attention due to their re-emergence and incidence in different areas of the world. Additional environmental and demographic considerations suggest that novel or known flaviviruses will continue to emerge in the future. Nevertheless, up to few years ago flaviviruses were considered low interest candidates for drug design. At the star…

Identification of specific histidines as pH sensors in flavivirus membrane fusion.

The flavivirus membrane fusion machinery, like that of many other enveloped viruses, is triggered by the acidic pH in endosomes after virus uptake by receptor-mediated endocytosis. It has been hypothesized that conserved histidines in the class II fusion protein E of these viruses function as molecular switches and, by their protonation, control the fusion process. Using the mutational analysis of recombinant subviral particles of tick-borne encephalitis virus, we provide direct experimental evidence that the initiation of fusion is crucially dependent on the protonation of one of the conserve…

Модель животного для щекотливого флавируса - Омскского вируса геморрагической лихорадки.

Серокомплекс тикаемого энцефалита (ТБЭ) состоит главным образом из вирусов, вызывающих неврологические заболевания; эти вирусы включают омскский вирус геморрагической лихорадки (OHFV), вирус, генетически связанный с другими серокомплексными вирусами ТБЭ, но циркулирующий в экологически отдельной нише и вызывающий явно различные заболевания человека. Цель этого исследования заключалась в изучении потенциальной малогабаритной модели для OHFV и в сопоставлении патологии инфекции с патологией нейротропического флавивируса Повассанского вируса (POWV). Зараженный POWV BALB/c мышей продемонстрировал

Совпадение в аннотации оригинала
The tickborne encephalitis (TBE) serocomplex of flaviviruses consists primarily of viruses that cause neurologic disease; these viruses include Omsk hemorrhagic fever virus (OHFV), a virus that is genetically related to other TBE serocomplex viruses but that circulates in an ecologically distinct niche and causes markedly different human disease. The objecti…

Assessment of the factors associated with flavivirus seroprevalence in a population in Southern Vietnam.

Dengue and Japanese encephalitis flaviviruses cause severe disease and are hyperendemic in southern Vietnam. This study assesses associations between sociodemographic factors and flavivirus seroprevalence in this region. Sera were collected from 308 community and hospital-based subjects between April 1996 and August 1997 and tested with an indirect ELISA. The factors associated with seroprevalence were assessed using multivariate logistic regression. In this first report of adjusted prevalence odds ratios (POR) for flavivirus infection in Vietnam, seropositivity was associated with increasing …

Cross-reactivity in flavivirus serology: new implications of an old finding?

To investigate the influence of pre-existing antibodies against tick-borne encephalitis (TBE) or yellow fever (YF) viruses on dengue virus a … assays should be taken into account in the interpretation of laboratory tests for the diagnosis of flavivirus infections and when undertaking seroepidemiological surveys.

[Prevalence of Flavivirus antibodies in Alouatta caraya primate autochthonous of Argentina].

Flavivirus constitute a human health problem in our country. Primates are known to participate in the maintenance of Dengue and Yellow Fever viruses. However, these animals play a role which still remains to be determined in the maintenance of other viruses with potential pathogenicity for human beings and/or animals. Detección of antibodies was performed for different flavivirus in 105 sera samples of Alouatta caraya primates by the hemagglutination inhibition (HI) test. The neutralization (NT) test confirmed only infections caused by St. Louis Encephalitis (SLE) virus with a high prevalence …

The interactions of the flavivirus envelope proteins: implications for virus entry and release.

Viral membrane proteins play an important role in the assembly and disassembly of enveloped viruses. Oligomerization and proteolytic cleavage events are involved in controlling the functions of these proteins during virus entry and release. Using tick-borne encephalitis virus as a model we have studied the role of the flavivirus envelope proteins E and prM/M in these processes. Experiments with acidotropic agents provide evidence that the virus is taken up by receptor-mediated endocytosis and that the acidic pH in endosomes plays an important role for virus entry. The envelope glycoprotein E u…

Evidence that the mature form of the flavivirus nonstructural protein NS1 is a dimer.

Evidence is presented which indicates that the dengue-2 virus nonstructural protein NS1 (soluble complement fixing antigen) exists in infect … e demonstrated that the appearance of the high-molecular-weight form of NS1 is a general feature of flavivirus infection. It is formed between 20 and 40 min after NS1 is synthesized and before the protein passes the Golgi apparatus. Both soluble and pelletable extracellular NS1 are also found as the high-molecular-weight form.

Influence of certain immunodepressants on experimental flavivirus and enterovirus infections in mice.

The effects of cyclophosphamide and 1,3-(piperidinomethyl)-5-phenyl-5-ethylbarbituric acid on certain flavi- and enterovirus infections in mice were studied. Differential enhancement of mortality rates after extraneural and, less markedly, intracerebral virus inoculation was noted. While depression of humoral and/or cell-mediated immunity is considered to be responsible for the effects observed in flavivirus infections, impaired function of the reticuloendothelial system seems to contribute mainly to the potentiation of Mengo virus infection by the immunodepressants used.

Assessment of flavivirus RNA stability and infectivity in various water environments.

INTRODUCTION: Flaviviruses such as dengue virus (DENV), Zika virus (ZIKV), Japanese encephalitis virus (JEV), and Yellow fever virus (YFV) are mosquito-borne RNA viruses causing major public health threats in major parts of the world. While DENV and ZIKV have been detected in urine samples, data on the presence and stability of flaviviruses in the water environment are limited. METHODS: In this study, we determined the stability and infectivity of flavivirus in different water environments by utilizing RT-qPCR and plaque assay to explore the feasibility of environmental detection and surveill…

Optimizing Humoral Immunity for Durable and Broad Protection in Flavivirus Vaccines.

Flavivirus infections, including dengue, Zika, West Nile, and Japanese encephalitis, remain a major global health concern. Although several vaccines are licensed, the durability and qualitative features of vaccine-induced antibodies differ substantially across platforms, leading to incomplete cross-protection and the risk of antibody-dependent enhancement. Long-term durability is exemplified by YF-17D, which induces protective antibodies that have been detectable for decades, whereas the JE SA14-14-2 vaccine has achieved program-level reductions in disease in endemic regions. In contrast, CYD-…

Riboflavin, a Potent Neuroprotective Vitamin: Focus on Flavivirus and Alphavirus Proteases.

Several neurotropic viruses are members of the flavivirus and alphavirus families. Infections caused by these viruses may cause long-term neurological sequelae in humans. The continuous emergence of infections caused by viruses around the world, such as the chikungunya virus (CHIKV) (Alphavirus genus), the zika virus (ZIKV) and the yellow fever virus (YFV) (both of the Flavivirus genus), warrants the development of new strategies to combat them. Our study demonstrates the inhibitory potential of the water-soluble vitamin riboflavin against NS2B/NS3pro of ZIKV and YFV and nsP2pro of CHIKV. Ribo…

Perturbation of Alphavirus and Flavivirus Infectivity by Components of the Bacterial Cell Wall.

The impact of the host microbiota on arbovirus infections is currently not well understood. Arboviruses are viruses transmitted through the … different virus families, including chikungunya virus of the Alphavirus genus and Zika virus of the Flavivirus genus, showing that this is a broad phenomenon. A modest inhibitory effect was observed following incubation with a panel of heat-inactivated bacteria, including bacteria residing on the skin. No viral inhibition was observed after preincubation of …

Neutrophil Recruitment and Participation in Severe Diseases Caused by Flavivirus Infection.

Neutrophils are first-line responders to infections and are recruited to target tissues through the action of chemoattractant molecules, such as chemokines. Neutrophils are crucial for the control of bacterial and fungal infections, but their role in the context of viral infections has been understudied. Flaviviruses are important human viral pathogens transmitted by arthropods. Infection with a flavivirus may result in a variety of complex disease manifestations, including hemorrhagic fever, encephalitis or congenital malformations. Our understanding of flaviviral diseases is incomplete, and …

Клетка памяти B и антитела реагируют на инфекцию и вакцинацию аромата.

Флавивирусы представляют собой группу одноствольных вирусов РНК, передаваемых комарами или клещами, которые могут вызывать широкий спектр клинических проявлений у людей и животных, включая асимптоматические, похожие на грипп заболевания, геморрагическую лихорадку, энцефалит, врожденные дефекты и смерть. Многие из них не имеют лицензий на вакцины для использования людьми. В качестве биомаркеров с точки зрения эффективности вакцины использовались разработка и внедрение клеток памяти B для нейтрализации антителных реакций, которые имеют важное значение для борьбы с инфекцией флавируса и его распр

Совпадение в аннотации оригинала
Flaviviruses are a group of mosquito- or tick-borne single-stranded RNA viruses that can cause a wide range of clinical manifestations in humans and animals, including asymptomatic, flu-like febrile illness, hemorrhagic fever, encephalitis, birth defects, and death. Many of them have no licensed vaccines available for human use. Memory B cell development and…

The role of anti-flavivirus humoral immune response in protection and pathogenesis.

Flavivirus infections are a public health threat in the world that requires the development of safe and effective vaccines. Therefore, the understanding of the anti-flavivirus humoral immune response is fundamental to future studies on flavivirus pathogenesis and the design of anti-flavivirus therapeutics. This review aims to provide an overview of the current understanding of the function and involvement of flavivirus proteins in the humoral immune response as well as the ability of the anti-envelope (anti-E) antibodies to interfere (neutralizing antibodies) or not (non-neutralizing antibodie…

A novel flavivirus strain detected in phlebotomine sandflies in Bosnia and Herzegovina.

Aim Phlebotominae sandflies are primary vectors of phleboviruses, causing the sandfly fever disease. The aim of this study was to detect and report the presence of flaviviruses in Phlebotominae sandflies captured in Bosnia and Herzegovina. Methods After a microscopic and morphometric analysis, the final identification of collected Phlebotomus specimens was confirmed by PCR, using a hemi-nested polymerase chain reaction on extracted and reversely transcribed RNA. Results We obtained a 155 nt long fragment of the viral non-structural protein 5 (NS5) gene (GenBank accession no. MN090154). The acq…

The Role of Mammalian Reservoir Hosts in Tick-Borne Flavivirus Biology.

Small-to-medium sized mammals and large animals are lucrative sources of blood meals for ixodid ticks that transmit life-threatening tick-borne flaviviruses (TBFVs). TBFVs have been isolated from various organs obtained from wild-caught Myodes and Apodemus species in Europe and Asia. Thus, these rodents are well-established reservoirs of TBFVs. Wild-caught Peromyscus species have demonstrated seropositivity against Powassan virus, the only TBFV known to circulate in North America, suggesting that they may play an important role in the biology of the virus in this geographic region. However, vi…