Journal articles on the topic 'Flavivirus'

To see the other types of publications on this topic, follow the link: Flavivirus.

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Flavivirus.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Qiu, Yang, Yan-Peng Xu, Miao Wang, Meng Miao, Hui Zhou, Jiuyue Xu, Jing Kong, et al. "Flavivirus induces and antagonizes antiviral RNA interference in both mammals and mosquitoes." Science Advances 6, no. 6 (February 2020): eaax7989. http://dx.doi.org/10.1126/sciadv.aax7989.

Full text
Abstract:
Mosquito-borne flaviviruses infect both mammals and mosquitoes. RNA interference (RNAi) has been demonstrated as an anti-flavivirus mechanism in mosquitoes; however, whether and how flaviviruses induce and antagonize RNAi-mediated antiviral immunity in mammals remains unknown. We show that the nonstructural protein NS2A of dengue virus-2 (DENV2) act as a viral suppressor of RNAi (VSR). When NS2A-mediated RNAi suppression was disabled, the resulting mutant DENV2 induced Dicer-dependent production of abundant DENV2-derived siRNAs in differentiated mammalian cells. VSR-disabled DENV2 showed severe replication defects in mosquito and mammalian cells and in mice that were rescued by RNAi deficiency. Moreover, NS2As of multiple flaviviruses act as VSRs in vitro and during viral infection in both organisms. Overall, our findings demonstrate that antiviral RNAi can be induced by flavivirus, while flavivirus uses NS2A as a bona fide VSR to evade RNAi in mammals and mosquitoes, highlighting the importance of RNAi in flaviviral vector-host life cycles.
APA, Harvard, Vancouver, ISO, and other styles
2

Wee, Sheena, Asfa Alli-Shaik, Relus Kek, Hannah L. F. Swa, Wei-Ping Tien, Vanessa W. Lim, Yee-Sin Leo, Lee-Ching Ng, Hapuarachchige C. Hapuarachchi, and Jayantha Gunaratne. "Multiplex targeted mass spectrometry assay for one-shot flavivirus diagnosis." Proceedings of the National Academy of Sciences 116, no. 14 (March 18, 2019): 6754–59. http://dx.doi.org/10.1073/pnas.1817867116.

Full text
Abstract:
Targeted proteomic mass spectrometry is emerging as a salient clinical diagnostic tool to track protein biomarkers. However, its strong analytical properties have not been exploited in the diagnosis and typing of flaviviruses. Here, we report the development of a sensitive and specific single-shot robust assay for flavivirus typing and diagnosis using targeted mass spectrometry technology. Our flavivirus parallel reaction monitoring assay (fvPRM) has the ability to track secreted flaviviral nonstructural protein 1 (NS1) over a broad diagnostic and typing window with high sensitivity, specificity, extendibility, and multiplexing capability. These features, pivotal and pertinent to efficient response toward flavivirus outbreaks, including newly emerging flavivirus strains, circumvent the limitations of current diagnostic assays.fvPRM thus carries high potential in positioning itself as a forerunner in delivering early and accurate diagnosis for disease management.
APA, Harvard, Vancouver, ISO, and other styles
3

van den Elsen, Kaïn, Jun Ping Quek, and Dahai Luo. "Molecular Insights into the Flavivirus Replication Complex." Viruses 13, no. 6 (May 21, 2021): 956. http://dx.doi.org/10.3390/v13060956.

Full text
Abstract:
Flaviviruses are vector-borne RNA viruses, many of which are clinically relevant human viral pathogens, such as dengue, Zika, Japanese encephalitis, West Nile and yellow fever viruses. Millions of people are infected with these viruses around the world each year. Vaccines are only available for some members of this large virus family, and there are no effective antiviral drugs to treat flavivirus infections. The unmet need for vaccines and therapies against these flaviviral infections drives research towards a better understanding of the epidemiology, biology and immunology of flaviviruses. In this review, we discuss the basic biology of the flavivirus replication process and focus on the molecular aspects of viral genome replication. Within the virus-induced intracellular membranous compartments, flaviviral RNA genome replication takes place, starting from viral poly protein expression and processing to the assembly of the virus RNA replication complex, followed by the delivery of the progeny viral RNA to the viral particle assembly sites. We attempt to update the latest understanding of the key molecular events during this process and highlight knowledge gaps for future studies.
APA, Harvard, Vancouver, ISO, and other styles
4

Wu, Bingan, Zhongtian Qi, and Xijing Qian. "Recent Advancements in Mosquito-Borne Flavivirus Vaccine Development." Viruses 15, no. 4 (March 23, 2023): 813. http://dx.doi.org/10.3390/v15040813.

Full text
Abstract:
Lately, the global incidence of flavivirus infection has been increasing dramatically and presents formidable challenges for public health systems around the world. Most clinically significant flaviviruses are mosquito-borne, such as the four serotypes of dengue virus, Zika virus, West Nile virus, Japanese encephalitis virus and yellow fever virus. Until now, no effective antiflaviviral drugs are available to fight flaviviral infection; thus, a highly immunogenic vaccine would be the most effective weapon to control the diseases. In recent years, flavivirus vaccine research has made major breakthroughs with several vaccine candidates showing encouraging results in preclinical and clinical trials. This review summarizes the current advancement, safety, efficacy, advantages and disadvantages of vaccines against mosquito-borne flaviviruses posing significant threats to human health.
APA, Harvard, Vancouver, ISO, and other styles
5

Heinz, Franz X., and Karin Stiasny. "Flaviviruses and flavivirus vaccines." Vaccine 30, no. 29 (June 2012): 4301–6. http://dx.doi.org/10.1016/j.vaccine.2011.09.114.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Liao, Ching-Len, Yi-Ling Lin, Bi-Ching Wu, Chang-Huei Tsao, Mei-Chuan Wang, Chiu-I. Liu, Yue-Ling Huang, Jui-Hui Chen, Jia-Pey Wang, and Li-Kuang Chen. "Salicylates Inhibit Flavivirus Replication Independently of Blocking Nuclear Factor Kappa B Activation." Journal of Virology 75, no. 17 (September 1, 2001): 7828–39. http://dx.doi.org/10.1128/jvi.75.17.7828-7839.2001.

Full text
Abstract:
ABSTRACT Flaviviruses comprise a positive-sense RNA genome that replicates exclusively in the cytoplasm of infected cells. Whether flaviviruses require an activated nuclear factor(s) to complete their life cycle and trigger apoptosis in infected cells remains elusive. Flavivirus infections quickly activate nuclear factor kappa B (NF-κB), and salicylates have been shown to inhibit NF-κB activation. In this study, we investigated whether salicylates suppress flavivirus replication and virus-induced apoptosis in cultured cells. In a dose-dependent inhibition, we found salicylates within a range of 1 to 5 mM not only restricted flavivirus replication but also abrogated flavivirus-triggered apoptosis. However, flavivirus replication was not affected by a specific NF-κB peptide inhibitor, SN50, and a proteosome inhibitor, lactacystin. Flaviviruses also replicated and triggered apoptosis in cells stably expressing IκBα-ΔN, a dominant-negative mutant that antagonizes NF-κB activation, as readily as in wild-type BHK-21 cells, suggesting that NF-κB activation is not essential for either flavivirus replication or flavivirus-induced apoptosis. Salicylates still diminished flavivirus replication and blocked apoptosis in the same IκBα-ΔN cells. This inhibition of flaviviruses by salicylates could be partially reversed by a specific p38 mitogen-activated protein (MAP) kinase inhibitor, SB203580. Together, these results show that the mechanism by which salicylates suppress flavivirus infection may involve p38 MAP kinase activity but is independent of blocking the NF-κB pathway.
APA, Harvard, Vancouver, ISO, and other styles
7

Habarugira, Gervais, Jasmin Moran, Jessica J. Harrison, Sally R. Isberg, Jody Hobson-Peters, Roy A. Hall, and Helle Bielefeldt-Ohmann. "Evidence of Infection with Zoonotic Mosquito-Borne Flaviviruses in Saltwater Crocodiles (Crocodylus porosus) in Northern Australia." Viruses 14, no. 5 (May 21, 2022): 1106. http://dx.doi.org/10.3390/v14051106.

Full text
Abstract:
The risk of flavivirus infections among the crocodilian species was not recognised until West Nile virus (WNV) was introduced into the Americas. The first outbreaks caused death and substantial economic losses in the alligator farming industry. Several other WNV disease episodes have been reported in crocodilians in other parts of the world, including Australia and Africa. Considering that WNV shares vectors with other flaviviruses, crocodilians are highly likely to also be exposed to flaviviruses other than WNV. A serological survey for flaviviral infections was conducted on saltwater crocodiles (Crocodylus porosus) at farms in the Northern Territory, Australia. Five hundred serum samples, collected from three crocodile farms, were screened using a pan-flavivirus-specific blocking ELISA. The screening revealed that 26% (n = 130/500) of the animals had antibodies to flaviviruses. Of these, 31.5% had neutralising antibodies to WNVKUN (Kunjin strain), while 1.5% had neutralising antibodies to another important flavivirus pathogen, Murray Valley encephalitis virus (MVEV). Of the other flaviviruses tested for, Fitzroy River virus (FRV) was the most frequent (58.5%) in which virus neutralising antibodies were detected. Our data indicate that farmed crocodiles in the Northern Territory are exposed to a range of potentially zoonotic flaviviruses, in addition to WNVKUN. While these flaviviruses do not cause any known diseases in crocodiles, there is a need to investigate whether infected saltwater crocodiles can develop a viremia to sustain the transmission cycle or farmed crocodilians can be used as sentinels to monitor the dynamics of arboviral infections in tropical areas.
APA, Harvard, Vancouver, ISO, and other styles
8

Fontoura, Marina Alves, Rebeca Fróes Rocha, and Rafael Elias Marques. "Neutrophil Recruitment and Participation in Severe Diseases Caused by Flavivirus Infection." Life 11, no. 7 (July 20, 2021): 717. http://dx.doi.org/10.3390/life11070717.

Full text
Abstract:
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 so is the role of neutrophils in such diseases. Here we present a comprehensive overview on the participation of neutrophils in severe disease forms evolving from flavivirus infection, focusing on the role of chemokines and their receptors as main drivers of neutrophil function. Neutrophil activation during viral infection was shown to interfere in viral replication through effector functions, but the resulting inflammation is significant and may be detrimental to the host. For congenital infections in humans, neutrophil recruitment mediated by CXCL8 would be catastrophic. Evidence suggests that control of neutrophil recruitment to flavivirus-infected tissues may reduce immunopathology in experimental models and patients, with minimal loss to viral clearance. Further investigation on the roles of neutrophils in flaviviral infections may reveal unappreciated functions of this leukocyte population while increasing our understanding of flaviviral disease pathogenesis in its multiple forms.
APA, Harvard, Vancouver, ISO, and other styles
9

Blahove, Maria Raisa, and James Richard Carter. "Flavivirus Persistence in Wildlife Populations." Viruses 13, no. 10 (October 18, 2021): 2099. http://dx.doi.org/10.3390/v13102099.

Full text
Abstract:
A substantial number of humans are at risk for infection by vector-borne flaviviruses, resulting in considerable morbidity and mortality worldwide. These viruses also infect wildlife at a considerable rate, persistently cycling between ticks/mosquitoes and small mammals and reptiles and non-human primates and humans. Substantially increasing evidence of viral persistence in wildlife continues to be reported. In addition to in humans, viral persistence has been shown to establish in mammalian, reptile, arachnid, and mosquito systems, as well as insect cell lines. Although a considerable amount of research has centered on the potential roles of defective virus particles, autophagy and/or apoptosis-induced evasion of the immune response, and the precise mechanism of these features in flavivirus persistence have yet to be elucidated. In this review, we present findings that aid in understanding how vector-borne flavivirus persistence is established in wildlife. Research studies to be discussed include determining the critical roles universal flavivirus non-structural proteins played in flaviviral persistence, the advancement of animal models of viral persistence, and studying host factors that allow vector-borne flavivirus replication without destructive effects on infected cells. These findings underscore the viral–host relationships in wildlife animals and could be used to elucidate the underlying mechanisms responsible for the establishment of viral persistence in these animals.
APA, Harvard, Vancouver, ISO, and other styles
10

Gibbs, Tristan, and David J. Speers. "Neurological disease caused by flavivirus infections." Microbiology Australia 39, no. 2 (2018): 99. http://dx.doi.org/10.1071/ma18029.

Full text
Abstract:
The Flavivirus genus contains dozens of species with varying geographical distributions. Most flavivirus infections in humans are asymptomatic or manifest as a non-specific febrile illness, sometimes accompanied by rash or arthralgia. Certain species are more commonly associated with neurological disease and may be termed neurotropic flaviviruses. Several flaviviruses endemic to Australia and our near northern neighbours are neurotropic, such as Murray Valley encephalitis virus, West Nile (Kunjin) virus and Japanese encephalitis virus. Flavivirus neurological disease ranges from self-limiting meningitis to fulminant encephalitis causing permanent debilitating neurological sequelae or death. The recent Zika virus outbreak in South America has highlighted the dramatic effects of flavivirus neurotropism on the developing brain. This article focuses on the neurotropic flaviviruses endemic to Australia and those of international significance.
APA, Harvard, Vancouver, ISO, and other styles
11

Reis, Vinicius Pinho dos, Markus Keller, Katja Schmidt, Rainer Günter Ulrich, and Martin Hermann Groschup. "αVβ3 Integrin Expression Is Essential for Replication of Mosquito and Tick-Borne Flaviviruses in Murine Fibroblast Cells." Viruses 14, no. 1 (December 23, 2021): 18. http://dx.doi.org/10.3390/v14010018.

Full text
Abstract:
The Flavivirus genus includes a number of important viruses that are pathogenic to humans and animals and are responsible for outbreaks across the globe. Integrins, a family of heterodimeric transmembrane molecules expressed in all nucleated cells mediate critical functions of cell physiology and cell cycle. Integrins were previously postulated to be involved in flavivirus entry and to modulate flavivirus replication efficiency. In the present study, mouse embryonic fibroblasts (MEF), lacking the expression of αVβ3 integrin (MEF-αVβ3−/−), were infected with four different flaviviruses, namely yellow fever virus (YFV), West Nile virus (WNV), Usutu virus (USUV) and Langat virus (LGTV). The effects of the αVβ3 integrin absence in double-knockout MEF-αVβ3−/− on flavivirus binding, internalization and replication were compared to the respective wild-type cells. Binding to the cell surface for all four flaviviruses was not affected by the ablation of αVβ3 integrin, whereas internalization of USUV and WNV was slightly affected by the loss of αVβ3 integrin expression. Most interestingly, the deletion of αVβ3 integrin strongly impaired replication of all flaviviruses with a reduction of up to 99% on virus yields and a strong reduction on flavivirus anti-genome RNA synthesis. In conclusion, our results demonstrate that αVβ3 integrin expression in flavivirus-susceptible cell lines enhances the flavivirus replication.
APA, Harvard, Vancouver, ISO, and other styles
12

Huhtamo, Eili, Niina Putkuri, Satu Kurkela, Tytti Manni, Antti Vaheri, Olli Vapalahti, and Nathalie Y. Uzcátegui. "Characterization of a Novel Flavivirus from Mosquitoes in Northern Europe That Is Related to Mosquito-Borne Flaviviruses of the Tropics." Journal of Virology 83, no. 18 (July 1, 2009): 9532–40. http://dx.doi.org/10.1128/jvi.00529-09.

Full text
Abstract:
ABSTRACT A novel flavivirus was isolated from mosquitoes in Finland, representing the first mosquito-borne flavivirus from Northern Europe. The isolate, designated Lammi virus (LAMV), was antigenically cross-reactive with other flaviviruses and exhibited typical flavivirus morphology as determined by electron microscopy. The genomic sequence of LAMV was highly divergent from the recognized flaviviruses, and yet the polyprotein properties resembled those of mosquito-borne flaviviruses. Phylogenetic analysis of the complete coding sequence showed that LAMV represented a distinct lineage related to the Aedes sp.-transmitted human pathogenic flaviviruses, similarly to the newly described Nounané virus (NOUV), a flavivirus from Africa (S. Junglen et al., J. Virol. 83:4462-4468, 2009). Despite the low sequence homology, LAMV and NOUV were phylogenetically grouped closely, likely representing separate species of a novel group of flaviviruses. Despite the biological properties preferring replication in mosquito cells, the genetic relatedness of LAMV to viruses associated with vertebrate hosts warrants a search for disease associations.
APA, Harvard, Vancouver, ISO, and other styles
13

Wahaab, Abdul, Bahar E. Mustafa, Muddassar Hameed, Nigel J. Stevenson, Muhammad Naveed Anwar, Ke Liu, Jianchao Wei, Yafeng Qiu, and Zhiyong Ma. "Potential Role of Flavivirus NS2B-NS3 Proteases in Viral Pathogenesis and Anti-flavivirus Drug Discovery Employing Animal Cells and Models: A Review." Viruses 14, no. 1 (December 28, 2021): 44. http://dx.doi.org/10.3390/v14010044.

Full text
Abstract:
Flaviviruses are known to cause a variety of diseases in humans in different parts of the world. There are very limited numbers of antivirals to combat flavivirus infection, and therefore new drug targets must be explored. The flavivirus NS2B-NS3 proteases are responsible for the cleavage of the flavivirus polyprotein, which is necessary for productive viral infection and for causing clinical infections; therefore, they are a promising drug target for devising novel drugs against different flaviviruses. This review highlights the structural details of the NS2B-NS3 proteases of different flaviviruses, and also describes potential antiviral drugs that can interfere with the viral protease activity, as determined by various studies. Moreover, optimized in vitro reaction conditions for studying the NS2B-NS3 proteases of different flaviviruses may vary and have been incorporated in this review. The increasing availability of the in silico and crystallographic/structural details of flavivirus NS2B-NS3 proteases in free and drug-bound states can pave the path for the development of promising antiflavivirus drugs to be used in clinics. However, there is a paucity of information available on using animal cells and models for studying flavivirus NS2B-NS3 proteases, as well as on the testing of the antiviral drug efficacy against NS2B-NS3 proteases. Therefore, on the basis of recent studies, an effort has also been made to propose potential cellular and animal models for the study of flavivirus NS2B-NS3 proteases for the purposes of exploring flavivirus pathogenesis and for testing the efficacy of possible drugs targets, in vitro and in vivo.
APA, Harvard, Vancouver, ISO, and other styles
14

Musso, Didier, and Philippe Desprès. "Serological Diagnosis of Flavivirus-Associated Human Infections." Diagnostics 10, no. 5 (May 14, 2020): 302. http://dx.doi.org/10.3390/diagnostics10050302.

Full text
Abstract:
Arthropod-borne viruses (arboviruses) belonging to the Flavivirus genus of the Flaviviridae family, are a major public health threat in tropical and subtropical regions, and have recently become a medical concern in temperate zones. Most flaviviruses are classified as zoonotic viruses. Human flavivirus infections can be asymptomatic, responsible for unspecific symptoms in the first few days following infection, or responsible for severe complications potentially resulting in death. During the first days following symptom onset, laboratory diagnosis of acute human flavivirus infection is mainly based on molecular detection of the viral genome by RT-PCR methods, followed by the capture of specific antibodies using serological tests after the first week of infection. The detection of antibodies that have virus neutralizing activity can be used to confirm flavivirus infection. However, human flavivirus infections induce the production of cross-reactive antibodies, often making serology inconclusive. Indeed, serological diagnosis of flavivirus infection can be hampered by a patient’s history of flavivirus exposure, particularly in regions where multiple antigenically related flaviviruses co-circulate. We focus our mini review on conventional immunoassays that allow the diagnosis of major flavivirus-associated human infections in basic, routine and high-profile central health centers; and the interpretation of diagnostic serology tests for patients living within different epidemiological situations.
APA, Harvard, Vancouver, ISO, and other styles
15

Dong, Hao-Long, Mei-Juan He, Qing-Yang Wang, Jia-Zhen Cui, Zhi-Li Chen, Xiang-Hua Xiong, Lian-Cheng Zhang, et al. "Rapid Generation of Recombinant Flaviviruses Using Circular Polymerase Extension Reaction." Vaccines 11, no. 7 (July 17, 2023): 1250. http://dx.doi.org/10.3390/vaccines11071250.

Full text
Abstract:
The genus Flavivirus is a group of arthropod-borne single-stranded RNA viruses, which includes important human and animal pathogens such as Japanese encephalitis virus (JEV), Zika virus (ZIKV), Dengue virus (DENV), yellow fever virus (YFV), West Nile virus (WNV), and Tick-borne encephalitis virus (TBEV). Reverse genetics has been a useful tool for understanding biological properties and the pathogenesis of flaviviruses. However, the conventional construction of full-length infectious clones for flavivirus is time-consuming and difficult due to the toxicity of the flavivirus genome to E. coli. Herein, we applied a simple, rapid, and bacterium-free circular polymerase extension reaction (CPER) method to synthesize recombinant flaviviruses in vertebrate cells as well as insect cells. We started with the de novo synthesis of the JEV vaccine strain SA-14-14-2 in Vero cells using CPER, and then modified the CPER method to recover insect-specific flaviviruses (ISFs) in mosquito C6/36 cells. Chimeric Zika virus (ChinZIKV) based on the Chaoyang virus (CYV) backbone and the Culex flavivirus reporter virus expressing green fluorescent protein (CxFV-GFP) were subsequently rescued in C6/36 cells. CPER is a simple method for the rapid generation of flaviviruses and other potential RNA viruses. A CPER-based recovery system for flaviviruses of different host ranges was established, which would facilitate the development of countermeasures against flavivirus outbreaks in the future.
APA, Harvard, Vancouver, ISO, and other styles
16

Zhao, Rong, Meiyue Wang, Jing Cao, Jing Shen, Xin Zhou, Deping Wang, and Jimin Cao. "Flavivirus: From Structure to Therapeutics Development." Life 11, no. 7 (June 25, 2021): 615. http://dx.doi.org/10.3390/life11070615.

Full text
Abstract:
Flaviviruses are still a hidden threat to global human safety, as we are reminded by recent reports of dengue virus infections in Singapore and African-lineage-like Zika virus infections in Brazil. Therapeutic drugs or vaccines for flavivirus infections are in urgent need but are not well developed. The Flaviviridae family comprises a large group of enveloped viruses with a single-strand RNA genome of positive polarity. The genome of flavivirus encodes ten proteins, and each of them plays a different and important role in viral infection. In this review, we briefly summarized the major information of flavivirus and further introduced some strategies for the design and development of vaccines and anti-flavivirus compound drugs based on the structure of the viral proteins. There is no doubt that in the past few years, studies of antiviral drugs have achieved solid progress based on better understanding of the flavivirus biology. However, currently, there are no fully effective antiviral drugs or vaccines for most flaviviruses. We hope that this review may provide useful information for future development of anti-flavivirus drugs and vaccines.
APA, Harvard, Vancouver, ISO, and other styles
17

Errico, John M., Laura A. VanBlargan, Christopher A. Nelson, Michael S. Diamond, and Daved H. Fremont. "Structural and Antigenic Features of Powassan Virus Envelope Protein." Journal of Immunology 200, no. 1_Supplement (May 1, 2018): 126.27. http://dx.doi.org/10.4049/jimmunol.200.supp.126.27.

Full text
Abstract:
Abstract Flaviviruses, such as West-Nile virus and Dengue virus, are insect-transmitted positive-sense RNA viruses that cause substantial morbidity and mortality worldwide. Powassan virus is an emerging encephalitic tick-borne flavivirus endemic to the northern United States, and is currently the only tick-transmitted flavivirus known to infect humans in North America. In cases of severe neurological disease, up to 10% of patients die of Powassan encephalitis, while many survivors are left with long-term neurological sequelae. Despite this, no vaccines or therapeutics are currently available to treat Powassan virus infection. Flaviviral vaccination efforts are commonly foiled by an inability to generate potent neutralizing responses, and by genesis of cross-reactive antibodies that paradoxically enhance infection by heterologous flaviviruses. These neutralizing antibodies, and their cross-reactive counterparts, commonly target structurally homologous epitopes present on many flaviviruses. Thus, understanding these epitopes has important implications for vaccine design. Little is known about the structure of Powassan virus envelope protein or host antibodies that target it. We have recombinantly expressed Powassan virus envelope protein and are currently working to determine its structure. As well, a panel of Powassan-virus specific monoclonal antibodies has been developed. Utilizing our recombinant protein, we are characterizing the epitopes these antibodies utilize as well as their biochemical and functional properties. These findings will aid vaccine and therapeutic design for Powassan virus and expand our understanding of the quintessential antigenic and structural features of flaviviral envelope proteins.
APA, Harvard, Vancouver, ISO, and other styles
18

Thibodeaux, Brett A., and John T. Roehrig. "Development of a Human-Murine Chimeric Immunoglobulin M Antibody for Use in the Serological Detection of Human Flavivirus Antibodies." Clinical and Vaccine Immunology 16, no. 5 (March 18, 2009): 679–85. http://dx.doi.org/10.1128/cvi.00354-08.

Full text
Abstract:
ABSTRACT Current diagnosis of human flaviviral infections relies heavily on serological techniques such as the immunoglobulin M (IgM) antibody capture enzyme-linked immunosorbent assay (MAC-ELISA). Broad application of this assay is hindered by a lack of standardized human positive-control sera that react with the wide variety of flaviviruses that can cause human disease, e.g., dengue virus (DENV), West Nile virus (WNV), yellow fever virus (YFV), Japanese encephalitis virus (JEV), and St. Louis encephalitis virus (SLEV). We have created a human-murine chimeric antibody combining the variable regions of the broadly flavivirus cross-reactive murine monoclonal antibody (MAb) 6B6C-1 and the constant region of human IgM to produce a standardized reagent capable of replacing human positive-control sera in a MAC-ELISA for the diagnosis of all human flaviviral infections. The human-murine chimeric IgM antibody secreted from plasmid-transformed Sp2/0-Ag14 cells had a level of serological activity identical to that of 6B6C-1 as measured by ELISA, immunoblotting, and MAC-ELISA for multiple members of the flavivirus genus, including WNV, SLEV, YFV, DENV, and JEV.
APA, Harvard, Vancouver, ISO, and other styles
19

Lee, Chyan-Jang, Hui-Ru Lin, Ching-Len Liao, and Yi-Ling Lin. "Cholesterol Effectively Blocks Entry of Flavivirus." Journal of Virology 82, no. 13 (April 30, 2008): 6470–80. http://dx.doi.org/10.1128/jvi.00117-08.

Full text
Abstract:
ABSTRACT Japanese encephalitis virus (JEV) and dengue virus serotype 2 (DEN-2) are enveloped flaviviruses that enter cells through receptor-mediated endocytosis and low pH-triggered membrane fusion and then replicate in intracellular membrane structures. Lipid rafts, cholesterol-enriched lipid-ordered membrane domains, are platforms for a variety of cellular functions. In this study, we found that disruption of lipid raft formation by cholesterol depletion with methyl-β-cyclodextrin or cholesterol chelation with filipin III reduces JEV and DEN-2 infection, mainly at the intracellular replication steps and, to a lesser extent, at viral entry. Using a membrane flotation assay, we found that several flaviviral nonstructural proteins are associated with detergent-resistant membrane structures, indicating that the replication complex of JEV and DEN-2 localizes to the membranes that possess the lipid raft property. Interestingly, we also found that addition of cholesterol readily blocks flaviviral infection, a result that contrasts with previous reports of other viruses, such as Sindbis virus, whose infectivity is enhanced by cholesterol. Cholesterol mainly affected the early step of the flavivirus life cycle, because the presence of cholesterol during viral adsorption greatly blocked JEV and DEN-2 infectivity. Flavirial entry, probably at fusion and RNA uncoating steps, was hindered by cholesterol. Our results thus suggest a stringent requirement for membrane components, especially with respect to the amount of cholesterol, in various steps of the flavivirus life cycle.
APA, Harvard, Vancouver, ISO, and other styles
20

Zhang, Naru, Chaoqun Li, Shibo Jiang, and Lanying Du. "Recent Advances in the Development of Virus-Like Particle-Based Flavivirus Vaccines." Vaccines 8, no. 3 (August 27, 2020): 481. http://dx.doi.org/10.3390/vaccines8030481.

Full text
Abstract:
Flaviviruses include several medically important viruses, such as Zika virus (ZIKV), Dengue virus (DENV), West Nile virus (WNV) and Japanese encephalitis virus (JEV). They have expanded in geographic distribution and refocused international attention in recent years. Vaccination is one of the most effective public health strategies for combating flavivirus infections. In this review, we summarized virus-like particle (VLP)-based vaccines against the above four mentioned flaviviruses. Potential strategies to improve the efficacy of VLP-based flavivirus vaccines were also illustrated. The applications of flavivirus VLPs as tools for viral detection and antiviral drug screening were finally proposed.
APA, Harvard, Vancouver, ISO, and other styles
21

Petruccelli, Angela, Tiziana Zottola, Gianmarco Ferrara, Valentina Iovane, Cristina Di Russo, Ugo Pagnini, and Serena Montagnaro. "West Nile Virus and Related Flavivirus in European Wild Boar (Sus scrofa), Latium Region, Italy: A Retrospective Study." Animals 10, no. 3 (March 16, 2020): 494. http://dx.doi.org/10.3390/ani10030494.

Full text
Abstract:
Background: A retrospective sero-survey for evidence of West Nile virus (WNV) infection in European wild boar (Sus scorfa) was conducted in the Latium region, Italy, on stored serum samples of the period November 2011 to January 2012. Methods: Sera were collected from 168 European wild boars and screened for antibodies to WNV and other Flaviviruses by competitive enzyme linked immunosorbent assay (cELISA). All sera positive for Flavivirus antibodies by cELISA were further examined by virus neutralization test (VNT). To test the presence of Flavivirus RNA in samples, an RT-PCR was performed using a pan-Flavivirus primers pair. Results: Thirteen wild boars (7.73%) were seropositive for Flaviviruses. The hemolysis of serum samples limited the interpretation of the VNT for 7 samples, confirming the presence of specific antibody against WNV in a single European wild boar serum sample. The presence of ELISA positive/VNT negative samples suggests the occurrence of non-neutralizing antibodies against WNV or other antigen-related Flaviviruses. No samples resulted positive for Flavivirus by RT-PCR assay. Conclusion: Although a moderately high percentage of animals with specific antibody for WNV has been detected in wild boar in other surveillance studies in Europe, this has not been reported previously in Italy. Together, these data indicate that European wild boar are exposed to WNV and/or other related-Flavivirus in central Italy and confirm the usefulness of wild ungulates, as suitable Flavivirus sentinels.
APA, Harvard, Vancouver, ISO, and other styles
22

Hou, Baohua, Hui Chen, Na Gao, and Jing An. "Cross-Reactive Immunity among Five Medically Important Mosquito-Borne Flaviviruses Related to Human Diseases." Viruses 14, no. 6 (June 2, 2022): 1213. http://dx.doi.org/10.3390/v14061213.

Full text
Abstract:
Flaviviruses cause a spectrum of potentially severe diseases. Most flaviviruses are transmitted by mosquitoes or ticks and are widely distributed all over the world. Among them, several mosquito-borne flaviviruses are co-epidemic, and the similarity of their antigenicity creates abundant cross-reactive immune responses which complicate their prevention and control. At present, only effective vaccines against yellow fever and Japanese encephalitis have been used clinically, while the optimal vaccines against other flavivirus diseases are still under development. The antibody-dependent enhancement generated by cross-reactive immune responses against different serotypes of dengue virus makes the development of the dengue fever vaccine a bottleneck. It has been proposed that the cross-reactive immunity elicited by prior infection of mosquito-borne flavivirus could also affect the outcome of the subsequent infection of heterologous flavivirus. In this review, we focused on five medically important flaviviruses, and rearranged and recapitulated their cross-reactive immunity in detail from the perspectives of serological experiments in vitro, animal experiments in vivo, and human cohort studies. We look forward to providing references and new insights for the research of flavivirus vaccines and specific prevention.
APA, Harvard, Vancouver, ISO, and other styles
23

Silvia, Ondine J., Geoffrey R. Shellam, and Nadezda Urosevic. "Innate resistance to flavivirus infection in mice controlled by Flv is nitric oxide-independent." Journal of General Virology 82, no. 3 (March 1, 2001): 603–7. http://dx.doi.org/10.1099/0022-1317-82-3-603.

Full text
Abstract:
Innate resistance to flaviviruses in mice is active in the brain where it restricts virus replication. This resistance is controlled by a single genetic locus, Flv, located on mouse chromosome 5 near the locus encoding the neuronal form of nitric oxide synthase (Nos1). Since nitric oxide (NO) has been implicated in antiviral activity, its involvement in natural resistance to flaviviruses has been hypothesized. Here we present data on NO production before and during flavivirus infection in both brain tissue and peritoneal macrophages from two flavivirus-resistant (Flv r) and one congenic susceptible (Flv s) mouse strains. This study provides evidence that NO is not involved in the expression of flavivirus resistance controlled by Flv since: (a) there is no difference in brain tissue NO levels between susceptible and resistant mice, and (b) lipopolysaccharide-induced NO does not abrogate the difference in flavivirus replication in peritoneal macrophages from susceptible and resistant mice.
APA, Harvard, Vancouver, ISO, and other styles
24

Cook, Shelley, Shannon N. Bennett, Edward C. Holmes, Reine De Chesse, Gregory Moureau, and Xavier de Lamballerie. "Isolation of a new strain of the flavivirus cell fusing agent virus in a natural mosquito population from Puerto Rico." Journal of General Virology 87, no. 4 (April 1, 2006): 735–48. http://dx.doi.org/10.1099/vir.0.81475-0.

Full text
Abstract:
The genus Flavivirus contains approximately 70 single-stranded, positive-sense RNA viruses that are mosquito-borne, tick-borne or have no known vector. Two discoveries support previous suggestions of the existence of a large number of unsampled flaviviruses: (i) a new flavivirus, Kamiti River virus, was recently isolated from Kenyan mosquitoes, and (ii) sequences with high similarity to those of flaviviruses have been found integrated into the genome of Aedes mosquitoes, suggesting a past infection with a virus (or viruses) that has yet to be discovered. These sequences were related most closely to a flavivirus that infects insects alone, cell fusing agent virus (CFAV). CFAV was originally isolated in the laboratory from an Aedes aegypti cell line. To date, this virus had not been found in the wild. In the present study, over 40 isolates of a novel strain of CFAV were discovered from mature mosquitoes sampled from the wild in Puerto Rico. The viral strain was present in a range of mosquito species, including Aedes aegypti, Aedes albopictus and Culex sp., from numerous locations across the island and, importantly, in mosquitoes of both sexes, suggesting vertical transmission. Here, results from viral screening, and cell culture and molecular identification of the infected mosquitoes are presented. Experimental-infection tests were also conducted by using the original CFAV strain and a highly efficient reverse-transcription mechanism has been documented, in which initiation of copying occurs at the 3′ terminus of either the genomic RNA or the intermediate of replication, potentially elucidating the mechanism by which flaviviral sequences may have integrated into mosquito genomes.
APA, Harvard, Vancouver, ISO, and other styles
25

Evangelista, Julio, Cristhopher Cruz, Carolina Guevara, Helvio Astete, Cristiam Carey, Tadeusz J. Kochel, Amy C. Morrison, Maya Williams, Eric S. Halsey, and Brett M. Forshey. "Characterization of a novel flavivirus isolated from Culex (Melanoconion) ocossa mosquitoes from Iquitos, Peru." Journal of General Virology 94, no. 6 (June 1, 2013): 1266–72. http://dx.doi.org/10.1099/vir.0.050575-0.

Full text
Abstract:
We describe the isolation and characterization of a novel flavivirus, isolated from a pool of Culex (Melanoconion) ocossa Dyar and Knab mosquitoes collected in 2009 in an urban area of the Amazon basin city of Iquitos, Peru. Flavivirus infection was detected by indirect immunofluorescent assay of inoculated C6/36 cells using polyclonal flavivirus antibodies (St. Louis encephalitis virus, yellow fever virus and dengue virus type 1) and confirmed by RT-PCR. Based on partial sequencing of the E and NS5 gene regions, the virus isolate was most closely related to the mosquito-borne flaviviruses but divergent from known species, with less than 45 and 71 % pairwise amino acid identity in the E and NS5 gene products, respectively. Phylogenetic analysis of E and NS5 amino acid sequences demonstrated that this flavivirus grouped with mosquito-borne flaviviruses, forming a clade with Nounané virus (NOUV). Like NOUV, no replication was detected in a variety of mammalian cells (Vero-76, Vero-E6, BHK, LLCMK, MDCK, A549 and RD) or in intracerebrally inoculated newborn mice. We tentatively designate this genetically distinct flavivirus as representing a novel species, Nanay virus, after the river near where it was first detected.
APA, Harvard, Vancouver, ISO, and other styles
26

Harrison, Jessica J., Jody Hobson-Peters, Helle Bielefeldt-Ohmann, and Roy A. Hall. "Chimeric Vaccines Based on Novel Insect-Specific Flaviviruses." Vaccines 9, no. 11 (October 22, 2021): 1230. http://dx.doi.org/10.3390/vaccines9111230.

Full text
Abstract:
Vector-borne flaviviruses are responsible for nearly half a billion human infections worldwide each year, resulting in millions of cases of debilitating and severe diseases and approximately 115,000 deaths. While approved vaccines are available for some of these viruses, the ongoing efficacy, safety and supply of these vaccines are still a significant problem. New technologies that address these issues and ideally allow for the safe and economical manufacture of vaccines in resource-poor countries where flavivirus vaccines are in most demand are urgently required. Preferably a new vaccine platform would be broadly applicable to all flavivirus diseases and provide new candidate vaccines for those diseases not yet covered, as well as the flexibility to rapidly pivot to respond to newly emerged flavivirus diseases. Here, we review studies conducted on novel chimeric vaccines derived from insect-specific flaviviruses that provide a potentially safe and simple system to produce highly effective vaccines against a broad spectrum of flavivirus diseases.
APA, Harvard, Vancouver, ISO, and other styles
27

Sotcheff, Stephanea, and Andrew Routh. "Understanding Flavivirus Capsid Protein Functions: The Tip of the Iceberg." Pathogens 9, no. 1 (January 5, 2020): 42. http://dx.doi.org/10.3390/pathogens9010042.

Full text
Abstract:
Flaviviruses are enveloped positive-sense single-stranded RNA arboviruses, infectious to humans and many other animals and are transmitted primarily via tick or mosquito vectors. Capsid is the primary structural protein to interact with viral genome within virus particles and is therefore necessary for efficient packaging. However, in cells, capsid interacts with many proteins and nucleic acids and we are only beginning to understand the broad range of functions of flaviviral capsids. It is known that capsid dimers interact with the membrane of lipid droplets, aiding in both viral packaging and storage of capsid prior to packaging. However, capsid dimers can bind a range of nucleic acid templates in vitro, and likely interact with a range of targets during the flavivirus lifecycle. Capsid may interact with host RNAs, resulting in altered RNA splicing and RNA transcription. Capsid may also bind short interfering-RNAs and has been proposed to sequester these species to protect flaviviruses from the invertebrate siRNA pathways. Capsid can also be found in the nucleolus, where it wreaks havoc on ribosome biogenesis. Here we review flavivirus capsid structure, nucleic acid interactions and how these give rise to multiple functions. We also discuss how these features might be exploited either in the design of effective antivirals or novel vaccine strategies.
APA, Harvard, Vancouver, ISO, and other styles
28

Singh, Rekha, and Sharone Green. "Enhanced CD8+ T-cell immunity following sequential flavivirus vaccines (39.19)." Journal of Immunology 184, no. 1_Supplement (April 1, 2010): 39.19. http://dx.doi.org/10.4049/jimmunol.184.supp.39.19.

Full text
Abstract:
Abstract Flaviviruses are arthropod-borne, RNA viruses of the Flaviviridae family. Flavivirus antigen-specific CD8+ T-cells are important in virus clearance. Primary exposure to a virus causes priming of CD8+ T-cells by virus-derived immunodominant peptides, leading to clonal differentiation and proliferation of effector cells followed by contraction and memory generation. ChimeriVax™ Flavivirus vaccines contain the nonstructural genes of the yellow fever (YF) vaccine and the prM and E genes of heterologous flaviviruses such as Japanese encephalitis (JE) and West Nile (WN) viruses. These chimeric vaccines induce both humoral and cell mediated immunity, however their potential to generate cross-reactive CD8+ T-cell responses to heterologous flaviviruses has not been investigated. In this study, mice were immunized with YF, YF/JE, or YF/WN vaccines followed by secondary homologous or heterologous immunization. We examined the hierarchy and function of CD8+ T-cell responses to a variable envelope epitope with those directed against a conserved immunodominant YF NS3 epitope. Using cell based immunological assays (ELISPOT and ICS), we found that the secondary immunization with heterologous chimeric flavivirus vaccines generate an enhanced cross-reactive CD8+ T-cell response that was dependent on the sequence of the primary immunization. Present results suggest that controlled exposure to multiple related flavivirus vaccines may lead to enhanced protection against related flaviviruses.
APA, Harvard, Vancouver, ISO, and other styles
29

Chaves, Andrea, Martha Piche-Ovares, Carlos N. Ibarra-Cerdeña, Eugenia Corrales-Aguilar, Gerardo Suzán, Andres Moreira-Soto, and Gustavo A. Gutiérrez-Espeleta. "Serosurvey of Nonhuman Primates in Costa Rica at the Human–Wildlife Interface Reveals High Exposure to Flaviviruses." Insects 12, no. 6 (June 15, 2021): 554. http://dx.doi.org/10.3390/insects12060554.

Full text
Abstract:
Arthropod-borne viruses belonging to the flavivirus genus possess an enormous relevance in public health. Neotropical non-human primates (NPs) have been proposed to be susceptible to flavivirus infections due to their arboreal and diurnal habits, their genetic similarity to humans, and their relative closeness to humans. However, the only known flavivirus in the American continent maintained by sylvatic cycles involving NPs is yellow fever virus (YFV), and NPs’ role as potential hosts of other flaviviruses is still unknown. Here, we examined flavivirus exposure in 86 serum samples including 83.7% samples from free-range and 16.3% from captive NPs living in flavivirus-endemic regions of Costa Rica. Serum samples were opportunistically collected throughout Costa Rica in 2000–2015. We used a highly specific micro-plaque reduction neutralization test (micro-PRNT) to determine the presence of antibodies against YFV, dengue virus 1–4 (DENV), Zika virus, West Nile virus (WNV), and Saint Louis encephalitis virus (SLEV). We found evidence of seropositive NPs with homotypic reactivity to SLEV 11.6% (10/86), DENV 10.5% (9/86), and WNV 2.3% (2/86). Heterotypic reactivity was determined in 3.5% (3/86) of individuals against DENV, 1.2% (1/86) against SLEV, and 1.2% (1/86) against WNV. We found that 13.9% (12/86) of NPs were positive for an undetermined flavivirus species. No antibodies against DENV-3, DENV-4, YFV, or ZIKV were found. This work provides compelling serological evidence of flavivirus exposure in Costa Rican NPs, in particular to DENV, SLEV, and WNV. The range of years of sampling and the region from where positives were detected coincide with those in which peaks of DENV in human populations were registered, suggesting bidirectional exposure due to human–wildlife contact or bridging vectors. Our work suggests the continuous exposure of wildlife populations to various flaviviruses of public health importance and underscores the necessity of further surveillance of flaviviruses at the human–wildlife interface in Central America.
APA, Harvard, Vancouver, ISO, and other styles
30

Alkan, Cigdem, Sonia Zapata, Laurence Bichaud, Grégory Moureau, Philippe Lemey, Andrew E. Firth, Tamara S. Gritsun, et al. "Ecuador Paraiso Escondido Virus, a New Flavivirus Isolated from New World Sand Flies in Ecuador, Is the First Representative of a Novel Clade in the Genus Flavivirus." Journal of Virology 89, no. 23 (September 9, 2015): 11773–85. http://dx.doi.org/10.1128/jvi.01543-15.

Full text
Abstract:
ABSTRACTA new flavivirus, Ecuador Paraiso Escondido virus (EPEV), named after the village where it was discovered, was isolated from sand flies (Psathyromyia abonnenci, formerlyLutzomyia abonnenci) that are unique to the New World. This represents the first sand fly-borne flavivirus identified in the New World. EPEV exhibited a typical flavivirus genome organization. Nevertheless, the maximum pairwise amino acid sequence identity with currently recognized flaviviruses was 52.8%. Phylogenetic analysis of the complete coding sequence showed that EPEV represents a distinct clade which diverged from a lineage that was ancestral to the nonvectored flaviviruses Entebbe bat virus, Yokose virus, and Sokoluk virus and also theAedes-associated mosquito-borne flaviviruses, which include yellow fever virus, Sepik virus, Saboya virus, and others. EPEV replicated in C6/36 mosquito cells, yielding high infectious titers, but failed to reproduce either in vertebrate cell lines (Vero, BHK, SW13, and XTC cells) or in suckling mouse brains. This surprising result, which appears to eliminate an association with vertebrate hosts in the life cycle of EPEV, is discussed in the context of the evolutionary origins of EPEV in the New World.IMPORTANCEThe flaviviruses are rarely (if ever) vectored by sand fly species, at least in the Old World. We have identified the first representative of a sand fly-associated flavivirus, Ecuador Paraiso Escondido virus (EPEV), in the New World. EPEV constitutes a novel clade according to current knowledge of the flaviviruses. Phylogenetic analysis of the virus genome showed that EPEV roots theAedes-associated mosquito-borne flaviviruses, including yellow fever virus. In light of this new discovery, the New World origin of EPEV is discussed together with that of the other flaviviruses.
APA, Harvard, Vancouver, ISO, and other styles
31

Dutta, Sudip Kumar, and Thomas Langenburg. "A Perspective on Current Flavivirus Vaccine Development: A Brief Review." Viruses 15, no. 4 (March 28, 2023): 860. http://dx.doi.org/10.3390/v15040860.

Full text
Abstract:
The flavivirus genus contains several clinically important pathogens that account for tremendous global suffering. Primarily transmitted by mosquitos or ticks, these viruses can cause severe and potentially fatal diseases ranging from hemorrhagic fevers to encephalitis. The extensive global burden is predominantly caused by six flaviviruses: dengue, Zika, West Nile, yellow fever, Japanese encephalitis and tick-borne encephalitis. Several vaccines have been developed, and many more are currently being tested in clinical trials. However, flavivirus vaccine development is still confronted with many shortcomings and challenges. With the use of the existing literature, we have studied these hurdles as well as the signs of progress made in flavivirus vaccinology in the context of future development strategies. Moreover, all current licensed and phase-trial flavivirus vaccines have been gathered and discussed based on their vaccine type. Furthermore, potentially relevant vaccine types without any candidates in clinical testing are explored in this review as well. Over the past decades, several modern vaccine types have expanded the field of vaccinology, potentially providing alternative solutions for flavivirus vaccines. These vaccine types offer different development strategies as opposed to traditional vaccines. The included vaccine types were live-attenuated, inactivated, subunit, VLPs, viral vector-based, epitope-based, DNA and mRNA vaccines. Each vaccine type offers different advantages, some more suitable for flaviviruses than others. Additional studies are needed to overcome the barriers currently faced by flavivirus vaccine development, but many potential solutions are currently being explored.
APA, Harvard, Vancouver, ISO, and other styles
32

Chuang, Fu-Kai, Ching-Len Liao, Ming-Kuan Hu, Yi-Lin Chiu, An-Rong Lee, Shih-Ming Huang, Yu-Lung Chiu, et al. "Antiviral Activity of Compound L3 against Dengue and Zika Viruses In Vitro and In Vivo." International Journal of Molecular Sciences 21, no. 11 (June 5, 2020): 4050. http://dx.doi.org/10.3390/ijms21114050.

Full text
Abstract:
Dengue virus (DENV) and Zika virus (ZIKV) are mosquito-borne flaviviruses that cause severe illness after infection. Currently, there are no specific or effective treatments against DENV and ZIKV. Previous studies have shown that tyrosine kinase activities and signal transduction are involved in flavivirus replication, suggesting a potential therapeutic strategy for DENV and ZIKV. In this study, we found that compound L3 can significantly reduce viral protein expression and viral titers in HEK-293, MCF-7, HepG2, and Huh-7 cells and exhibits superior therapeutic efficacy against flaviviral infection compared to other tyrosine kinase inhibitors. In addition, compound L3 can decrease endogenous HER2 activation and inhibit the phosphorylation of the HER2 downstream signaling molecules Src and ERK1/2, the levels of which have been associated with viral protein expression in MCF-7 cells. Moreover, silencing HER2 diminished DENV-2 and ZIKV expression in MCF-7 cells, which suggests that HER2 activity is involved in flavivirus replication. Furthermore, in DENV-2-infected AG129 mice, treatment with compound L3 increased the survival rates and reduced the viremia levels. Overall, compound L3 demonstrates therapeutic efficacy both in vitro and in vivo and could be developed as a promising antiviral drug against emerging flaviviruses or for concurrent DENV and ZIKV outbreaks.
APA, Harvard, Vancouver, ISO, and other styles
33

Neufeldt, Christopher J., Mirko Cortese, Pietro Scaturro, Berati Cerikan, Jeremy Wideman, Keisuke Tabata, Thais Morase, Olga Oleksiuk, Andreas Pichlmair, and Ralf Bartenschlager. "ER-Shaping Atlastin Proteins Act as Central Hubs to Promote Flavivirus Replication and Virion Assembly." Proceedings 50, no. 1 (June 10, 2020): 31. http://dx.doi.org/10.3390/proceedings2020050031.

Full text
Abstract:
Members of the Flavivirus genus rely extensively on the host cell endomembrane network to generate complex membranous replication organelles (ROs) that facilitate viral genome replication and the production of virus particles. For dengue virus and Zika virus, these ROs included vesicles which are formed through membrane invagination into the endoplasmic reticulum (ER) lumen, termed invaginated vesicles or vesicle packets (VPs), as well as large areas of bundled smooth ER, termed convoluted membranes. Though the morphology of these virus-induced membrane structures has been well characterized, the viral and host constituents that make up flaviviral ROs are still poorly understood. Here, we identified a subset of ER resident proteins (atlastins), normally required for maintaining ER tubule networks, as critical host factors for flavivirus infection. Specific changes in atlastin (ATL) levels had dichotomous effects on flaviviruses with ATL2 depletion, leading to replication organelle defects and ATL3 depletion to changes in viral assembly/release pathways. These different depletion phenotypes allowed us to exploit virus infection to characterize non-conserved functional domains between the three atlastin paralogues. Additionally, we established the ATL interactome and show how it is reprogrammed upon viral infection. Screening of specific ATL interactors confirmed non-redundant ATL functions and identified a role for ATL3 in vesicle trafficking. Our data demonstrate that ATLs are central host factors that coordinate the ER network and shape the ER during flavivirus infection.
APA, Harvard, Vancouver, ISO, and other styles
34

Ke, Po-Yuan. "The Multifaceted Roles of Autophagy in Flavivirus-Host Interactions." International Journal of Molecular Sciences 19, no. 12 (December 7, 2018): 3940. http://dx.doi.org/10.3390/ijms19123940.

Full text
Abstract:
Autophagy is an evolutionarily conserved cellular process in which intracellular components are eliminated via lysosomal degradation to supply nutrients for organelle biogenesis and metabolic homeostasis. Flavivirus infections underlie multiple human diseases and thus exert an immense burden on public health worldwide. Mounting evidence indicates that host autophagy is subverted to modulate the life cycles of flaviviruses, such as hepatitis C virus, dengue virus, Japanese encephalitis virus, West Nile virus and Zika virus. The diverse interplay between autophagy and flavivirus infection not only regulates viral growth in host cells but also counteracts host stress responses induced by viral infection. In this review, we summarize the current knowledge on the role of autophagy in the flavivirus life cycle. We also discuss the impacts of virus-induced autophagy on the pathogeneses of flavivirus-associated diseases and the potential use of autophagy as a therapeutic target for curing flavivirus infections and related human diseases.
APA, Harvard, Vancouver, ISO, and other styles
35

Berneck, Beatrice Sarah, Alexandra Rockstroh, Jasmin Fertey, Thomas Grunwald, and Sebastian Ulbert. "A Recombinant Zika Virus Envelope Protein with Mutations in the Conserved Fusion Loop Leads to Reduced Antibody Cross-Reactivity upon Vaccination." Vaccines 8, no. 4 (October 13, 2020): 603. http://dx.doi.org/10.3390/vaccines8040603.

Full text
Abstract:
Zika virus (ZIKV) is a zoonotic, human pathogenic, and mosquito-borne flavivirus. Its distribution is rapidly growing worldwide. Several attempts to develop vaccines for ZIKV are currently ongoing. Central to most vaccination approaches against flavivirus infections is the envelope (E) protein, which is the major target of neutralizing antibodies. Insect-cell derived, recombinantly expressed variants of E from the flaviviruses West Nile and Dengue virus have entered clinical trials in humans. Also for ZIKV, these antigens are promising vaccine candidates. Due to the structural similarity of flaviviruses, cross-reactive antibodies are induced by flavivirus antigens and have been linked to the phenomenon of antibody-dependent enhancement of infection (ADE). Especially the highly conserved fusion loop domain (FL) in the E protein is a target of such cross-reactive antibodies. In areas where different flaviviruses co-circulate and heterologous infections cannot be ruled out, this is of concern. To exclude the possibility that recombinant E proteins of ZIKV might induce ADE in infections with related flaviviruses, we performed an immunization study with an insect-cell derived E protein containing four mutations in and near the FL. Our data show that this mutant antigen elicits antibodies with equal neutralizing capacity as the wildtype equivalent. However, it induces much less serological cross-reactivity and does not cause ADE in vitro. These results indicate that mutated variants of the E protein might lead to ZIKV and other flavivirus vaccines with increased safety profiles.
APA, Harvard, Vancouver, ISO, and other styles
36

Chin, Kim-Ling, Kim-Kee Tan, Sazaly Abu Bakar, and Nurhafiza Zainal. "Resveratrol as an epigenetic therapy for flavivirus infection: A narrative review." Asian Pacific Journal of Tropical Medicine 16, no. 12 (December 2023): 546–57. http://dx.doi.org/10.4103/1995-7645.391776.

Full text
Abstract:
Flaviviruses are a group of positive-stranded RNA viruses that cause a broad spectrum of severe illnesses in humans worldwide. Clinical manifestations of flavivirus infections range from mild febrile illness to hemorrhage, shock, and neurological manifestations. Flavivirus infections cause a substantial global health impact, with an estimated more than 400 million cases of infections annually. Hence, an understanding of flavivirus-host interaction is urgently needed for new antiviral therapeutic strategies. In recent years, many aspects concerning epigenetic therapy for viral infections have been addressed, including methylation of the genome, acetylation/deacetylation of histone complex and microRNA regulation. In this context, we surveyed and reviewed the literature and summarized the epigenetic effects of resveratrol, a natural polyphenol with potential anti-viral properties, on flavivirus infections.
APA, Harvard, Vancouver, ISO, and other styles
37

Choi, Kyung H. "The Role of the Stem-Loop A RNA Promoter in Flavivirus Replication." Viruses 13, no. 6 (June 9, 2021): 1107. http://dx.doi.org/10.3390/v13061107.

Full text
Abstract:
An essential challenge in the lifecycle of RNA viruses is identifying and replicating the viral genome amongst all the RNAs present in the host cell cytoplasm. Yet, how the viral polymerase selectively recognizes and copies the viral RNA genome is poorly understood. In flaviviruses, the 5′-end of the viral RNA genome contains a 70 nucleotide-long stem-loop, called stem-loop A (SLA), which functions as a promoter for genome replication. During replication, flaviviral polymerase NS5 specifically recognizes SLA to both initiate viral RNA synthesis and to methylate the 5′ guanine cap of the nascent RNA. While the sequences of this region vary between different flaviviruses, the three-way junction arrangement of secondary structures is conserved in SLA, suggesting that viruses recognize a common structural feature to replicate the viral genome rather than a particular sequence. To better understand the molecular basis of genome recognition by flaviviruses, we recently determined the crystal structures of flavivirus SLAs from dengue virus (DENV) and Zika virus (ZIKV). In this review, I will provide an overview of (1) flaviviral genome replication; (2) structures of viral SLA promoters and NS5 polymerases; and (3) and describe our current model of how NS5 polymerases specifically recognize the SLA at the 5′ terminus of the viral genome to initiate RNA synthesis at the 3′ terminus.
APA, Harvard, Vancouver, ISO, and other styles
38

Chaley, M. B., Zh S. Tyulko, and V. A. Kutyrkin. "Flavivirus Species Recognition Based On the Polyprotein Coding Sequences." Mathematical Biology and Bioinformatics 14, no. 2 (November 19, 2019): 533–42. http://dx.doi.org/10.17537/2019.14.533.

Full text
Abstract:
Method recognizing the flavivirus species, including a subtype recognition, that based on the genome sequence analysis, is proposed. This method takes into consideration frequency characteristics of amino acid codons in the coding sequences of full-length polyprotein of flavivirus genomes. High reliability of the method is proved in recognizing flavivirus genomes from 15 groups of different species and sub-types, that are sufficiently represented in the GenBank database. Ten various species of the flaviviruses, four sub-types of Dengue virus and Kunjin virus, that is suggested to be a sub-type of West Nile virus, are considered in the work.
APA, Harvard, Vancouver, ISO, and other styles
39

Zhang, Xianwen, Yuhan Li, Yingyi Cao, Ying Wu, and Gong Cheng. "The Role of Noncoding RNA in the Transmission and Pathogenicity of Flaviviruses." Viruses 16, no. 2 (February 2, 2024): 242. http://dx.doi.org/10.3390/v16020242.

Full text
Abstract:
Noncoding RNAs (ncRNAs) constitute a class of RNA molecules that lack protein-coding capacity. ncRNAs frequently modulate gene expression through specific interactions with target proteins or messenger RNAs, thereby playing integral roles in a wide array of cellular processes. The Flavivirus genus comprises several significant members, such as dengue virus (DENV), Zika virus (ZIKV), and yellow fever virus (YFV), which have caused global outbreaks, resulting in high morbidity and mortality in human populations. The life cycle of arthropod-borne flaviviruses encompasses their transmission between hematophagous insect vectors and mammalian hosts. During this process, a complex three-way interplay occurs among the pathogen, vector, and host, with ncRNAs exerting a critical regulatory influence. ncRNAs not only constitute a crucial regulatory mechanism that has emerged from the coevolution of viruses and their hosts but also hold potential as antiviral targets for controlling flavivirus epidemics. This review introduces the biogenesis of flavivirus-derived ncRNAs and summarizes the regulatory roles of ncRNAs in viral replication, vector-mediated viral transmission, antiviral innate immunity, and viral pathogenicity. A profound comprehension of the interplay between ncRNAs and flaviviruses will help formulate efficacious prophylactic and therapeutic strategies against flavivirus-related diseases.
APA, Harvard, Vancouver, ISO, and other styles
40

Suzuki, Youichi, and Takeshi Murakawa. "Restriction of Flaviviruses by an Interferon-Stimulated Gene SHFL/C19orf66." International Journal of Molecular Sciences 23, no. 20 (October 20, 2022): 12619. http://dx.doi.org/10.3390/ijms232012619.

Full text
Abstract:
Flaviviruses (the genus Flavivirus of the Flaviviridae family) include many arthropod-borne viruses, often causing life-threatening diseases in humans, such as hemorrhaging and encephalitis. Although the flaviviruses have a significant clinical impact, it has become apparent that flavivirus replication is restricted by cellular factors induced by the interferon (IFN) response, which are called IFN-stimulated genes (ISGs). SHFL (shiftless antiviral inhibitor of ribosomal frameshifting) is a novel ISG that inhibits dengue virus (DENV), West Nile virus (WNV), Zika virus (ZIKV), and Japanese encephalitis virus (JEV) infections. Interestingly, SHFL functions as a broad-spectrum antiviral factor exhibiting suppressive activity against various types of RNA and DNA viruses. In this review, we summarize the current understanding of the molecular mechanisms by which SHFL inhibits flavivirus infection and discuss the molecular basis of the inhibitory mechanism using a predicted tertiary structure of SHFL generated by the program AlphaFold2.
APA, Harvard, Vancouver, ISO, and other styles
41

Biering, Scott B., David L. Akey, Marcus P. Wong, W. Clay Brown, Nicholas T. N. Lo, Henry Puerta-Guardo, Francielle Tramontini Gomes de Sousa, et al. "Structural basis for antibody inhibition of flavivirus NS1–triggered endothelial dysfunction." Science 371, no. 6525 (January 7, 2021): 194–200. http://dx.doi.org/10.1126/science.abc0476.

Full text
Abstract:
Medically important flaviviruses cause diverse disease pathologies and collectively are responsible for a major global disease burden. A contributing factor to pathogenesis is secreted flavivirus nonstructural protein 1 (NS1). Despite demonstrated protection by NS1-specific antibodies against lethal flavivirus challenge, the structural and mechanistic basis remains unknown. Here, we present three crystal structures of full-length dengue virus NS1 complexed with a flavivirus–cross-reactive, NS1-specific monoclonal antibody, 2B7, at resolutions between 2.89 and 3.96 angstroms. These structures reveal a protective mechanism by which two domains of NS1 are antagonized simultaneously. The NS1 wing domain mediates cell binding, whereas the β-ladder triggers downstream events, both of which are required for dengue, Zika, and West Nile virus NS1–mediated endothelial dysfunction. These observations provide a mechanistic explanation for 2B7 protection against NS1-induced pathology and demonstrate the potential of one antibody to treat infections by multiple flaviviruses.
APA, Harvard, Vancouver, ISO, and other styles
42

Pettersson, John H. O., and Omar Fiz-Palacios. "Dating the origin of the genus Flavivirus in the light of Beringian biogeography." Journal of General Virology 95, no. 9 (September 1, 2014): 1969–82. http://dx.doi.org/10.1099/vir.0.065227-0.

Full text
Abstract:
The genus Flavivirus includes some of the most important human viral pathogens, and its members are found in all parts of the populated world. The temporal origin of diversification of the genus has long been debated due to the inherent problems with dating deep RNA virus evolution. A generally accepted hypothesis suggests that Flavivirus emerged within the last 10 000 years. However, it has been argued that the tick-borne Powassan flavivirus was introduced into North America some time between the opening and closing of the Beringian land bridge that connected Asia and North America 15 000–11 000 years ago, indicating an even older origin for Flavivirus. To determine the temporal origin of Flavivirus, we performed Bayesian relaxed molecular clock dating on a dataset with high coverage of the presently available Flavivirus diversity by combining tip date calibrations and internal node calibration, based on the Powassan virus and Beringian land bridge biogeographical event. Our analysis suggested that Flavivirus originated ~85 000 (64 000–110 000) or 120 000 (87 000–159 000) years ago, depending on the circumscription of the genus. This is significantly older than estimated previously. In light of our results, we propose that it is likely that modern humans came in contact with several members of the genus Flavivirus much earlier than suggested previously, and that it is possible that the spread of several flaviviruses coincided with, and was facilitated by, the migration and population expansion of modern humans out of Africa.
APA, Harvard, Vancouver, ISO, and other styles
43

Castilho, Leda R., Nathalia R. Mattos, Wallace S. Abreu, and Melissa L. E. Gutarra. "Virus-Like Particles (VLPs) as Important Tools for Flavivirus Vaccine Development." Biologics 2, no. 4 (October 31, 2022): 226–42. http://dx.doi.org/10.3390/biologics2040018.

Full text
Abstract:
Flaviviruses, such as dengue, zika, yellow fever, West Nile, and Japanese encephalitis virus, are RNA viruses belonging to the Flaviviridae family (genus Flavivirus). They represent an important global health concern, since most areas of the world are endemic for at least one of these viruses. Although vaccines for five flaviviruses currently exist, there is a need for new vaccines to protect from established, emerging, and reemerging flaviviruses. Yellow fever vaccine shortages experienced in the last decade, combined with the risk of YFV spread to Asia and the restrictions of vaccine administration to certain population segments, show that even when a highly efficacious vaccine is available, new and improved vaccines might be needed. Virus-like particles (VLPs) are multiprotein structures that mimic the virus, but do not contain its genetic material. As such, VLPs have an excellent track record of strong immunogenicity and high safety, dating back to the introduction of the first recombinant hepatitis B vaccine in the 1980s. Flavivirus-like particles (FVLPs) have been extensively studied, especially for DENV, JEV, and ZIKV, and could give rise to next-generation recombinant subunit flavivirus vaccines based on VLPs incorporating molecular features intended to ensure high efficacy and minimize the risk of antibody-dependent enhancement (ADE) upon infection with other flaviviruses.
APA, Harvard, Vancouver, ISO, and other styles
44

Ci, Yali, and Lei Shi. "Compartmentalized replication organelle of flavivirus at the ER and the factors involved." Cellular and Molecular Life Sciences 78, no. 11 (April 12, 2021): 4939–54. http://dx.doi.org/10.1007/s00018-021-03834-6.

Full text
Abstract:
AbstractFlaviviruses are positive-sense single-stranded RNA viruses that pose a considerable threat to human health. Flaviviruses replicate in compartmentalized replication organelles derived from the host endoplasmic reticulum (ER). The characteristic architecture of flavivirus replication organelles includes invaginated vesicle packets and convoluted membrane structures. Multiple factors, including both viral proteins and host factors, contribute to the biogenesis of the flavivirus replication organelle. Several viral nonstructural (NS) proteins with membrane activity induce ER rearrangement to build replication compartments, and other NS proteins constitute the replication complexes (RC) in the compartments. Host protein and lipid factors facilitate the formation of replication organelles. The lipid membrane, proteins and viral RNA together form the functional compartmentalized replication organelle, in which the flaviviruses efficiently synthesize viral RNA. Here, we reviewed recent advances in understanding the structure and biogenesis of flavivirus replication organelles, and we further discuss the function of virus NS proteins and related host factors as well as their roles in building the replication organelle.
APA, Harvard, Vancouver, ISO, and other styles
45

Grard, Gilda, Jean-Jacques Lemasson, Massamba Sylla, Audrey Dubot, Shelley Cook, Jean-Francois Molez, Xavier Pourrut, et al. "Ngoye virus: a novel evolutionary lineage within the genus Flavivirus." Journal of General Virology 87, no. 11 (November 1, 2006): 3273–77. http://dx.doi.org/10.1099/vir.0.82071-0.

Full text
Abstract:
By using degenerate primers deduced from conserved patterns in the flavivirus polymerase gene, a novel RNA virus was discovered in Rhipicephalus ticks sampled from members of the family Bovidae in Senegal. It was named Ngoye virus (NGOV) after the location from which it was isolated. Viral particles could be observed by electron microscopy, but isolation in vertebrate or invertebrate cell lines or by intracerebral infection of newborn mice remained unsuccessful. This is atypical of recognized arboviruses. The characterization of 4176 nt of the non-structural genes revealed that NGOV is a novel flavivirus species. It forms a distinct phylogenetic lineage related distantly to previously identified members of the genus Flavivirus. Analysis of genetic data suggested that the processing of the NGOV polyprotein and the organization of its replication complex are similar to those of flaviviruses. Together with other recent data, these findings suggest that a large number of viruses related distantly to ‘classical’ arthropod-borne flaviviruses remain to be discovered.
APA, Harvard, Vancouver, ISO, and other styles
46

Calzolari, Mattia, Líbia Zé-Zé, Daniel Růžek, Ana Vázquez, Claire Jeffries, Francesco Defilippo, Hugo Costa Osório, et al. "Detection of mosquito-only flaviviruses in Europe." Journal of General Virology 93, no. 6 (June 1, 2012): 1215–25. http://dx.doi.org/10.1099/vir.0.040485-0.

Full text
Abstract:
The genus Flavivirus, family Flaviviridae, includes a number of important arthropod-transmitted human pathogens such as dengue viruses, West Nile virus, Japanese encephalitis virus and yellow fever virus. In addition, the genus includes flaviviruses without a known vertebrate reservoir, which have been detected only in insects, particularly in mosquitoes, such as cell fusing agent virus, Kamiti River virus, Culex flavivirus, Aedes flavivirus, Quang Binh virus, Nakiwogo virus and Calbertado virus. Reports of the detection of these viruses with no recognized pathogenic role in humans are increasing in mosquitoes collected around the world, particularly in those sampled in entomological surveys targeting pathogenic flaviviruses. The presence of six potential flaviviruses, detected from independent European arbovirus surveys undertaken in the Czech Republic, Italy,Portugal, Spain and the UK between 2007 and 2010, is reported in this work. Whilst the Aedes flaviviruses, detected in Italy from Aedes albopictus mosquitoes, had already been isolated in Japan, the remaining five viruses have not been reported previously: one was detected in Italy, Portugal and Spain from Aedes mosquitoes (particularly from Aedes caspius), one in Portugal and Spain from Culex theileri mosquitoes, one in the Czech Republic and Italy from Aedes vexans, one in the Czech Republic from Aedes vexans and the last in the UK from Aedes cinereus. Phylogenetic analysis confirmed the close relationship of these putative viruses to other insect-only flaviviruses.
APA, Harvard, Vancouver, ISO, and other styles
47

Balingit, Jean Claude, Minh Huong Phu Ly, Mami Matsuda, Ryosuke Suzuki, Futoshi Hasebe, Kouichi Morita, and Meng Ling Moi. "A Simple and High-Throughput ELISA-Based Neutralization Assay for the Determination of Anti-Flavivirus Neutralizing Antibodies." Vaccines 8, no. 2 (June 10, 2020): 297. http://dx.doi.org/10.3390/vaccines8020297.

Full text
Abstract:
Mosquito-borne flavivirus infections, including dengue virus and Zika virus, are major public health threats globally. While the plaque reduction neutralization test (PRNT) is considered the gold standard for determining neutralizing antibody levels to flaviviruses, the assay is time-consuming and laborious. This study, therefore, aimed to develop an enzyme-linked immunosorbent assay (ELISA)-based microneutralization test (EMNT) for the detection of neutralizing antibodies to mosquito-borne flaviviruses. The inhibition of viral growth due to neutralizing antibodies was determined colorimetrically by using EMNT. Given the significance of Fcγ-receptors (FcγR) in antibody-mediated neutralization and antibody-dependent enhancement (ADE) of flavivirus infection, non-FcγR and FcγR-expressing cell lines were used in the EMNT to allow the detection of the sum of neutralizing and immune-enhancing antibody activity as the neutralizing titer. Using anti-flavivirus monoclonal antibodies and clinical samples, the utility of EMNT was evaluated by comparing the end-point titers of the EMNT and the PRNT. The correlation between EMNT and PRNT titers was strong, indicating that EMNT was robust and reproducible. The new EMNT assay combines the biological functional assessment of virus neutralization activity and the technical advantages of ELISA and, is simple, reliable, practical, and could be automated for high-throughput implementation in flavivirus surveillance studies and vaccine trials.
APA, Harvard, Vancouver, ISO, and other styles
48

Saivish, Marielena Vogel, Gabriela de Lima Menezes, Vivaldo Gomes da Costa, Liliane Nebo, Gislaine Celestino Dutra da Silva, Carolina Colombelli Pacca, Rafael Elias Marques, Maurício Lacerda Nogueira, and Roosevelt Alves Da Silva. "Structural Insights into Plasticity and Discovery of Flavonoid Allosteric Inhibitors of Flavivirus NS2B–NS3 Protease." Biophysica 3, no. 1 (February 1, 2023): 71–92. http://dx.doi.org/10.3390/biophysica3010006.

Full text
Abstract:
Flaviviruses are among the most critical pathogens in tropical regions; they cause various severe diseases in developing countries but are not restricted to these countries. The development of antiviral therapeutics is crucial for managing flavivirus outbreaks. Ten proteins are encoded in the flavivirus RNA. The N2B–NS3pro protein complex plays a fundamental role in flavivirus replication and is a promising drug target; however, no flavivirus protease inhibitors have progressed to the preclinical stage. This study analyzed the structural models and plasticity of the NS2B–NS3pro protein complex of five medically important non-dengue flaviviruses (West Nile, Rocio, Ilhéus, yellow fever, and Saint Louis encephalitis). The flavonoids amentoflavone, tetrahydrorobustaflavone, and quercetin were selected for their exceptional binding energies as potential inhibitors of the NS2B–NS3pro protein complex. AutoDock Vina results ranged from −7.0 kcal/mol to −11.5 kcal/mol and the compounds preferentially acted non-competitively. Additionally, the first structural model for the NS2B–NS3pro protein complex was proposed for Ilhéus and Rocio viruses. The NS2B–NS3pro protease is an attractive molecular target for drug development. The three identified natural flavonoids showed great inhibitory potential against the viral species. Nevertheless, further in silico and in vitro studies are required to obtain more information regarding NS2B–NS3pro inhibition by these flavonoids and their therapeutic potential.
APA, Harvard, Vancouver, ISO, and other styles
49

JAEGER, A., S. LECOLLINET, C. BECK, M. BASTIEN, M. LE CORRE, K. DELLAGI, H. PASCALIS, T. BOULINIER, and C. LEBARBENCHON. "Serological evidence for the circulation of flaviviruses in seabird populations of the western Indian Ocean." Epidemiology and Infection 144, no. 3 (July 21, 2015): 652–60. http://dx.doi.org/10.1017/s0950268815001661.

Full text
Abstract:
SUMMARYBirds play a central role in the epidemiology of several flaviviruses of concern for public and veterinary health. Seabirds represent the most abundant and widespread avifauna in the western Indian Ocean and may play an important role as host reservoirs and spreaders of arthropod-borne pathogens such as flaviviruses. We report the results of a serological investigation based on blood samples collected from nine seabird species from seven islands in the Indian Ocean. Using a commercial competitive enzyme-linked immunosorbent assay directed against the prototypic West Nile flavivirus, antibodies against flaviviruses were detected in the serum of 47 of the 855 seabirds tested. They were detected in bird samples from three islands and from four bird species. Seroneutralization tests on adults and chicks suggested that great frigatebirds (Fregata minor) from Europa were infected by West Nile virus during their non-breeding period, and that Usutu virus probably circulated within bird colonies on Tromelin and on Juan de Nova. Real-time polymerase chain reactions performed on bird blood samples did not yield positive results precluding the genetic characterization of flavivirus using RNA sequencing. Our findings stress the need to further investigate flavivirus infections in arthropod vectors present in seabird colonies.
APA, Harvard, Vancouver, ISO, and other styles
50

Beck, Cécile, Philippe Desprès, Sylvie Paulous, Jessica Vanhomwegen, Steeve Lowenski, Norbert Nowotny, Benoit Durand, et al. "A High-Performance Multiplex Immunoassay for Serodiagnosis of Flavivirus-Associated Neurological Diseases in Horses." BioMed Research International 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/678084.

Full text
Abstract:
West Nile virus (WNV), Japanese encephalitis virus (JEV), and tick-borne encephalitis virus (TBEV) are flaviviruses responsible for severe neuroinvasive infections in humans and horses. The confirmation of flavivirus infections is mostly based on rapid serological tests such as enzyme-linked immunosorbent assays (ELISAs). These tests suffer from poor specificity, mainly due to antigenic cross-reactivity among flavivirus members. Robust diagnosis therefore needs to be validated through virus neutralisation tests (VNTs) which are time-consuming and require BSL3 facilities. The flavivirus envelope (E) glycoprotein ectodomain is composed of three domains (D) named DI, DII, and DIII, with EDIII containing virus-specific epitopes. In order to improve the serological differentiation of flavivirus infections, the recombinant soluble ectodomain of WNV E (WNV.sE) and EDIIIs (rEDIIIs) of WNV, JEV, and TBEV were synthesised using theDrosophilaS2 expression system. Purified antigens were covalently bonded to fluorescent beads. The microspheres coupled to WNV.sE or rEDIIIs were assayed with about 300 equine immune sera from natural and experimental flavivirus infections and 172 nonimmune equine sera as negative controls. rEDIII-coupled microspheres captured specific antibodies against WNV, TBEV, or JEV in positive horse sera. This innovative multiplex immunoassay is a powerful alternative to ELISAs and VNTs for veterinary diagnosis of flavivirus-related diseases.
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography