Flaviviruses are important arthropod-borne pathogens that represent an immense global health problem.Their unprecedented epidemic rate and unpredictable clinical features underscore an urgent need for antiviral interv...Flaviviruses are important arthropod-borne pathogens that represent an immense global health problem.Their unprecedented epidemic rate and unpredictable clinical features underscore an urgent need for antiviral interventions.Dehydroepiandrosterone(DHEA)is a natural occurring adrenal-derived steroid in the human body that has been associated in protection against various infections.In the present study,the plaque assay based primary screening was conducted on 32 synthetic derivatives of DHEA against Japanese encephalitis virus(JEV)to identify potent anti-flaviviral compounds.Based on primary screening,HAAS-AV3026 and HAAS-AV3027 were selected as hits from DHEA derivatives that exhibited strong antiviral activity against JEV(IC_(50)=2.13 and 1.98μmol/L,respectively)and Zika virus(ZIKV)(IC_(50)=3.73 and 3.42μmol/L,respectively).Mechanism study indicates that HAAS-AV3026 and HAAS-AV3027 do not exhibit inhibitory effect on flavivirus binding and entry process,while significantly inhibit flavivirus infection at the replication stage.Moreover,indirect immunofluorescence assay,Western blot analyses,and quantitative reverse transcription-PCR(qRT-PCR)revealed a potent antiviral activity of DHEA derivatives hits against JEV and ZIKV in terms of inhibition of viral infection,protein production,and viral RNA synthesis in Vero cells.Taken together,our results may provide a basis for the development of new antivirals against flaviviruses.展开更多
The aim of this study is to explore the phylogenetic relationship of flaviviruses with the known viruses and to establish a rapid PCR-based method for the characterization of the flaviviruses. To this end, phylogeneti...The aim of this study is to explore the phylogenetic relationship of flaviviruses with the known viruses and to establish a rapid PCR-based method for the characterization of the flaviviruses. To this end, phylogenetic analysis of 25 different strains of flaviviruses was carried out on the basis of the full length genomic sequences as well as the sequences of the individual genes and their untranslated regions (UTRs). From this analysis and the extensive sequence alignment studies, a generic primer pair was identified for amplification of a highly conserved region in the NS5 gene, a molecular marker designed as NS5MM in this study, which was different from NS5 region used previously by other groups. This generic primer pair had been validated by using 22 different strains of flaviviruses in the present study. Furthermore, we have successfully applied this new approach to the rapid identification and characterization of 3 new strains of flaviviruses recently isolated in China.展开更多
Flaviviruses are a genus of mostly arthropod-borne RNA viruses that cause a range of pathologies in humans.Basic knowledge on flaviviruses is rapidly expanding,partly due to their status as frequent emerging or re-eme...Flaviviruses are a genus of mostly arthropod-borne RNA viruses that cause a range of pathologies in humans.Basic knowledge on flaviviruses is rapidly expanding,partly due to their status as frequent emerging or re-emerging pathogens.Flaviviruses include the dengue,Zika,West Nile,tick-borne encephalitis and yellow fever viruses(DENV,ZIKV,WNV,TBEV and YFV,respectively).As is the case with other families of viruses,the success of productive infection of human cells by flaviviruses depends in part on the antiviral activity of a heterogeneous group of cellular antiviral proteins called restriction factors.Restriction factors are the effector proteins of the cell-autonomous innate response against viruses,an immune pathway that also includes virus sensors as well as intracellular and extracellular signal mediators such as type I interferons(IFN-I).In this review,I summarize recent progress toward the identification and characterization of flavivirus restriction factors.In particular,I focus on IFI6,Schlafen 11,FMRP,OAS-RNase L,RyDEN,members of the TRIM family of proteins(TRIM5α,TRIM19,TRIM56,TRIM69 and TRIM79α)and a new mechanism of action proposed for viperin.Recent and future studies on this topic will lead to a more complete picture of the flavivirus restrictome,defined as the ensemble of cellular factors with demonstrated anti-flaviviral activity.展开更多
Flaviviruses,which include globally impactful pathogens,such as West Nile virus,yellow fever virus,Zika virus,Japanese encephalitis virus,and dengue virus,contribute significantly to human infections.Despite the ongoi...Flaviviruses,which include globally impactful pathogens,such as West Nile virus,yellow fever virus,Zika virus,Japanese encephalitis virus,and dengue virus,contribute significantly to human infections.Despite the ongoing emergence and resurgence of flavivirus-mediated pathogenesis,the absence of specific therapeutic options remains a challenge in the prevention and treatment of flaviviral infections.Through the intricate processes of fusion,transcription,replication,and maturation,the complex interplay of viral and host metabolic interactions affects pathophysiology.Crucial interactions involve metabolic molecules,such as amino acids,glucose,fatty acids,and nucleotides,each playing a pivotal role in the replication and maturation of flaviviruses.These viral-host metabolic molecular interactions hijack and modulate the molecular mechanisms of host metabolism.A comprehensive understanding of these intricate metabolic pathways offers valuable insights,potentially unveiling novel targets for therapeutic interventions against flaviviral pathogenesis.This review emphasizes promising avenues for the development of therapeutic agents that target specific metabolic molecules,such as amino acids,glucose,fatty acids,and nucleotides,which interact with flavivirus replication and are closely linked to the modulation of host metabolism.The clinical limitations of current drugs have prompted the development of new inhibitory strategies for flaviviruses based on an understanding of the molecular interactions between the virus and the host.展开更多
Flaviviruses affect the lives of millions of people in endemic regions and also have the potential to impact nonendemic areas.Factors such as climate change,global warming,deforestation,and increased travel and trade ...Flaviviruses affect the lives of millions of people in endemic regions and also have the potential to impact nonendemic areas.Factors such as climate change,global warming,deforestation,and increased travel and trade are linked to the spread of flaviviruses into new habitats and host species.Given the absence of specific treatments and the limited availability of vaccines,it is imperative to understand the biology of flaviviruses and develop rapid and sensitive diagnostic tests.These measures are essential for preventing the transmission of these potentially life-threatening pathogens.Flavivirus infections are mainly diagnosed using conventional methods.However,these techniques present several drawbacks,including high expenses,time-consuming procedures,and the need for skilled professionals.The search for fast,easy-to-use,and affordable alternative techniques as a feasible solution for developing countries is leading to the search for new methods in the diagnosis of flavivi-ruses,such as biosensors.This review provides a comprehensive overview of different biosensor detection strategies for flaviviruses and describes recent advances in diagnostic technologies.Finally,we explore their future prospects and potential applications in pathogen detection.This review serves as a valuable resource to understand advances in ongoing research into new biosensor-based diagnostic methods for flaviviruses.展开更多
Arboviral diseases are viral infections transmitted to humans through the bites of arthropods,such as mosquitoes,often causing a variety of pathologies associated with high levels of morbidity and mortality.Over the p...Arboviral diseases are viral infections transmitted to humans through the bites of arthropods,such as mosquitoes,often causing a variety of pathologies associated with high levels of morbidity and mortality.Over the past decades,these infections have proven to be a significant challenge to health systems worldwide,particularly following the considerable geographic expansion of the dengue virus(DENV)and its most recent outbreak in Latin America as well as the difficult-tocontrol outbreaks of yellow fever virus(YFV),chikungunya virus(CHIKV),and Zika virus(ZIKV),leaving behind a substantial portion of the population with complications related to these infections.Currently,the world is experiencing a period of intense globalization,which,combined with global warming,directly contributes to wider dissemination of arbovirus vectors across the globe.Consequently,all continents remain on high alert for potential new outbreaks.Thus,this review aims to provide a comprehensive understanding of the pathogenesis of the four main arboviruses today(DENV,ZIKV,YFV,and CHIKV)discussing their viral characteristics,immune responses,and mechanisms of viral evasion,as well as important clinical aspects for patient management.This includes associated symptoms,laboratory tests,treatments,existing or developing vaccines and the main associated complications,thus integrating a broad historical,scientific and clinical approach.展开更多
Emerging infectious diseases are a major threat to biodiversity and an important public health issue.Flaviviruses are the cause of several emerging vector-borne zoonotic arboviruses whose distribution is currently inc...Emerging infectious diseases are a major threat to biodiversity and an important public health issue.Flaviviruses are the cause of several emerging vector-borne zoonotic arboviruses whose distribution is currently increasing in Europe.The evidence that West Nile virus(WNV)circulates in resident and migratory species has implications for both animal and public health and should therefore be studied in depth.USUTU(USUV),Bagaza(BAGV)and tick-borne encephalitis virus(TBEV)are other viruses that are beginning to spread more widely.An integrated surveillance program,namely in birds,is essential for reducing the risk of infection in human populations within the One Health principles.In the present study,wild birds admitted to wildlife rehabilitation centers in Portugal were sampled.Two hundred eight blood samples were assayed serologically for antibodies to flaviviruses by using a commercial ELISA kit.An over-all seroprevalence of 19.6%(95%confidence interval[CI]:13.7-26.7%)was observed.Antibodies against flaviviruses were detected in 13(35.1%)different species of wild birds.Accipitriformes(26.7%;95%CI:18.5-36.2%)and Strigi-formes(26.7%;95%CI:14.6-42.0%)were the orders with the highest seroprevalence rates recorded.There were no statistically significant differences(p=0.725)between the geographical regions(NUTSⅡ)studied,but a statistically significant difference(p=0.017)was found between sex(male:34.4%;female:4.8%).A higher seroprevalence was detected in adults(32.1%)than in juvenile birds(9.3%)(p=0.014),and age was considered a risk factor for flavivirus infection in wild birds(odds ratio 1.4;95%CI:0.5-4.0).More epidemiological studies are needed in Portugal since the actual spread of the genus Flavivirus throughout the country is unknown.展开更多
BACKGROUND In tropical Asia,arbovirus-induced encephalitis continues to be a serious public health issue.Encephalitis is caused by wide range of neurotropic pathogens,and flaviviruses are one of the main causative age...BACKGROUND In tropical Asia,arbovirus-induced encephalitis continues to be a serious public health issue.Encephalitis is caused by wide range of neurotropic pathogens,and flaviviruses are one of the main causative agents in the area.Sri Lanka reports a considerable number of central nervous system infections annually.Both dengue and Japanese encephalitis are endemic,and cases of Zika and West Nile virus infections were reported occasionally in Sri Lanka.Although reported number of Japanese encephalitis cases has reduced in the past,aetiological diagnosis in majority of encephalitis cases is still unknown.AIM To detect dengue virus(DENV)infections in individuals in the central region of Sri Lanka who were clinically suspected of having encephalitis.METHODS A retrospective observational analysis was conducted on 99 cerebrospinal fluid samples received to a virology laboratory from patients in the central part of Sri Lanka who were clinically suspected of having encephalitis.Samples were analyzed using reverse transcriptase polymerase chain reaction(RT-PCR)with universal flavivirus primers to detect flaviviral RNA followed by DENV serotyping real-time RT-PCR,and an immunoglobulin M(IgM)detection enzyme-linked immunosorbent assay to detect IgM antibodies indicative of a possible recent DENV infection.RESULTS DENV aetiology was detected in 6(6.06%)cerebrospinal fluid samples,and all were confirmed as DENV infections.A single positive result(1.01%)was yielded through RT-PCR and was identified as DENV serotype 3.Serology testing detected 05(5.05%)anti-dengue IgM positives and further investigation indicated probable DENV aetiology.Among positives 02(33.33%)were children(aged less than 14 years),and rest were adults.CONCLUSION These findings underscore the presence of DENV-associated central nervous system infections and highlight the need for broader surveillance and more advanced diagnostic approaches in the future.展开更多
Dengue virus(DENV)is a mosquito-borne pathogen responsible for a spectrum of illnesses,including dengue fever,dengue hemorrhagic fever,and dengue shock syndrome.Nearly half of the global population is at risk of DENV ...Dengue virus(DENV)is a mosquito-borne pathogen responsible for a spectrum of illnesses,including dengue fever,dengue hemorrhagic fever,and dengue shock syndrome.Nearly half of the global population is at risk of DENV infection,making it a pressing public health issue worldwide.The limited cross-protection among the four DENV serotypes(DENV1-4)and the phenomenon of antibody-dependent enhancement(ADE)have posed significant challenges to the development of effective dengue vaccines.Furthermore,there are currently no specific antiviral treatments available.This review provides an overview of DENV's key characteristics,clinical manifestations,and recent advancements in antiviral drug development-including the repurposing of approved drugs,peptidebased antiviral agents,therapeutic antibodies,natural products with antiviral potential,and host factor inhibitors-aiming to offer critical insights to inform strategies for managing and preventing dengue outbreaks.展开更多
Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the genus Flavivirus within the Flaviviridae family.Four serotypes,DENV 1-4,are distributed globally[1].Hanoi metropolitan city is an endemi...Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the genus Flavivirus within the Flaviviridae family.Four serotypes,DENV 1-4,are distributed globally[1].Hanoi metropolitan city is an endemic hotspot for DENV transmission in Vietnam[2,3].The largest outbreak occurred in 2017,with more than 36000 cases and 7 deaths reported,causing by all four serotypes with the predominance of DENV1,following by DENV2[4,5].During the following dengue season,we collected 390 blood and serum samples from 197 hospitalized patients in a national hospital in Hanoi city,Northern Vietnam to identify the circulating DENV serotypes responsible for the 2018-2019 outbreak.展开更多
There are presently no in-depth published neuropsychological studies of West Nile Virus (WNV) encephalitis patients that have been well-correlated with high resolution structural MRI. In this study a middleaged male w...There are presently no in-depth published neuropsychological studies of West Nile Virus (WNV) encephalitis patients that have been well-correlated with high resolution structural MRI. In this study a middleaged male who developed West Nile Virus encephalitis five years previously was examined three times over a two year period. We examined him with the Wechsler Adult Intelligence Scales—Fourth Edition and the Wechsler Memory Scale—Fourth Edition (WAIS-IV/WMS-IV) and Advanced Clinical Solutions battery supplemented by tests of attention, executive, motor and sensory functions. Neuroradiological imaging revealed hypodensities within the left hippocampus in the axial and coronal planes with T2-FLAIR MRI. The man was previously high functioning and although he had prior history of well-controlled epilepsy it seems unlikely that the epilepsy could fully account for the neuropathological changes. The patient had previously completed a demanding six year double science degree program before he became ill with WNV and he had been a successful manager and director of a research company. Delayed auditory memory scores were at least two standard deviation units below age expected levels and semantic fluency and Booklet Category Tests of executive function were also in the impaired range. Moreover the illness onset profile of muscle weakness, extreme fatigue, memory complaints as well as inability to carry out research projects involving planning on the job were highly consistent with WNV encephalitis. If the memory and executive function deficits had been premorbid manifestations of epilepsy it is unlikely he would have attained the levels he did educationally and occupationally. This left hippocampal lesion is characteristic of other encephalitic viral infections such as herpes simplex virus. To our knowledge this is the first lateralized WNV encephalitis medial temporal lobe patient in the published literature.展开更多
The family of flaviviruses is one of the most medically important groups of emerging arthropod-borne viruses. Host cell cytoskeletons have been reported to have close contact with flaviviruses during virus entry, intr...The family of flaviviruses is one of the most medically important groups of emerging arthropod-borne viruses. Host cell cytoskeletons have been reported to have close contact with flaviviruses during virus entry, intracellular transport, replication, and egress process, although many detailed mechanisms are still unclear. This article provides a brief overview of the function of the most prominent flaviviruses-induced or-hijacked cytoskeletal structures including actin, microtubules and intermediate filaments, mainly focus on infection by dengue virus, Zika virus and West Nile virus. We suggest that virus interaction with host cytoskeleton to be an interesting area of future research.展开更多
Dengue virus(DENV) has four distinct serotypes. DENV infection can result in classic dengue fever and life-threatening dengue hemorrhagic fever/dengue shock syndrome. In recent decades, DENV infection has become an im...Dengue virus(DENV) has four distinct serotypes. DENV infection can result in classic dengue fever and life-threatening dengue hemorrhagic fever/dengue shock syndrome. In recent decades, DENV infection has become an important public health concern in epidemic-prone areas. Vaccination is the most effective measure to prevent and control viral infections. However, several challenges impede the development of effective DENV vaccines, such as the lack of suitable animal models and the antibody-dependent enhancement phenomenon. Although no licensed DENV vaccine is available, significant progress has been made. This review summarizes candidate DENV vaccines from recent investigations.展开更多
Many flaviviruses are significant human pathogens causing considerable disease burdens,including encephalitis and hemorrhagic fever,in the regions in which they are endemic.A paucity of treatments for flaviviral infec...Many flaviviruses are significant human pathogens causing considerable disease burdens,including encephalitis and hemorrhagic fever,in the regions in which they are endemic.A paucity of treatments for flaviviral infections has driven interest in drug development targeting proteins essential to flavivirus replication,such as the viral protease.During viral replication,the flavivirus genome is translated as a single polyprotein precursor,which must be cleaved into individual proteins by a complex of the viral protease,NS3,and its cofactor,NS2B.Because this cleavage is an obligate step of the viral life-cycle,the flavivirus protease is an attractive target for antiviral drug development.In this review,we will survey recent drug development studies targeting the NS3 active site,as well as studies targeting an NS2B/NS3interaction site determined from flavivirus protease crystal structures.展开更多
In order to establish double antibody sandwich enzyme-linked immunosorbent assay （DAS-ELISA） for detection of duck or goose flavivirus, polyclonal antibody against the flavivirus strain JS804 in geese and monoclonal...In order to establish double antibody sandwich enzyme-linked immunosorbent assay （DAS-ELISA） for detection of duck or goose flavivirus, polyclonal antibody against the flavivirus strain JS804 in geese and monoclonal antibody against the E protein of flavivirus strain JS804 in geese were used as the capture antibody and detection antibody, respectively. The optimal dilution of the capture antibody and detecting antibody capable of detecting the flavivirus strain JS804 in geese were 1：3 200 and 1：160 in the check-board titration, respectively. The reaction time of sample was 1 h, and the optimal working dilution of HRP-labeled goat-anti-mouse IgG was 1：10 000. The positive standard value was 0.247 （OD450.m）. The geese flavivirus could be detected at a minimal concentration of 1.875 μg mL^-1. The ELISA had no cross-reaction with Newcastle disease virus （NDV）, Avian influenza virus （AIV）, Infectious bronchitis virus （IBV）, Infectious bursal disease virus （IBDV）, Duck hepatitis virus （DHV）, and Gosling plague virus （GPV）. Twenty clinical samples were detected by the DAS-ELISA and RT-PCR respectively, with the agreement rate of 75%. The results revealed that the DAS-ELISA possessed favorable specificity and higher sensitivity, indicating a suitable method for rapid detection of the duck or goose flavivirus.展开更多
Many flaviviruses are emerging and reemerging pathogens, such as West Nile virus （WNV）, dengue virus （DENV）, yellow fever virus （YFV）, and Japanese encephalitis virus. Serological assay is the dominant method fo...Many flaviviruses are emerging and reemerging pathogens, such as West Nile virus （WNV）, dengue virus （DENV）, yellow fever virus （YFV）, and Japanese encephalitis virus. Serological assay is the dominant method for diagnosis of flavivirus infections in human. Because antibodies generated during flavivirus infections cross-react with other flavivirus members, plaque reduction neutralization test （PRNT） is the only available assay to determine the infecting flavivirus type. Since PRNT requires culturing raw viruses, it must be performed in biosafety levet-3 or level-4 containment for many flaviviruses, and takes more than ten days to complete. To overcome these problems, we have developed flavivirus viral-like particles （VLPs） that could be used to replace raw viruses in the neutralization assay. The VLPs were prepared by trans packaging a luciferase-reporting replicon with viral structural proteins. This novel assay involves three simple steps： （i） VLPs from a panel of flaviviruses are incubated with flavivirus-infected sera at 37℃ for 1 h; （ii）the neutralized VLPs are used to infect Vero cells; and （iii） the infected cells are measured for luciferase activities at 22 h post-infection. The virus type whose VLP is most efficiently neutralized by the serum specimen （as quantified by the luciferase activities） is the etiologic agent. As a proof-of-concept, we show that a WNV-infected mouse serum neutralized the WNV VLP more efficiently and selectively than the DENV and YFV VLPs. Our results demonstrate that the VLP neutralization assay maintains the ＂gold standard＂ of the classic PRNT; importantly, it shortens the assay time from 〉10 days to 〈1 day, and can be performed in biosafety level-2 facility.展开更多
Dengue is a common pathogenic disease often proving fatal,more commonly affecting the tropics.Aedes mosquito is the vector for this disease,and outbreaks of dengue often cause mass damage to life.The current review is...Dengue is a common pathogenic disease often proving fatal,more commonly affecting the tropics.Aedes mosquito is the vector for this disease,and outbreaks of dengue often cause mass damage to life.The current review is an effort to present an insight into the causes,etiology,symptoms,transmission,diagnosis,major organs affected,mitigation and line of treatment of this disease with special emphasis on dings of natural origin.The disease has a potential to spread as an endemic,often claiming several lives and thus requires concerted efforts to work out better treatment options.Traditional medicine offers an alternative solution and could be explored as a safer treatment option.Development of a successful vaccine and immunization technique largely remains a challenge and a better antiviral approach needs to be worked out to complement the supportive therapy.No single synthetic molecule has found to be wholly effective enough to offer curative control and the line of treatment mostly utilizes a combination of fluid replacement and antipyretics-analgesics like molecules to provide symptomatic relief.展开更多
Based on the Culex flavivirus (CxFV) E gene sequences in GenBank, CxFV-specific primers and probes were designed for real-time reverse transcription-polymerase chain reaction (RT-qPCR). The specificity test revealed t...Based on the Culex flavivirus (CxFV) E gene sequences in GenBank, CxFV-specific primers and probes were designed for real-time reverse transcription-polymerase chain reaction (RT-qPCR). The specificity test revealed that CxFV could be detected using RT-qPCR with the specific CxFV primers and probes; other species of arboviruses were not detected. The stability test demonstrated a coefficient of variation of <1.5%. A quantitative standard curve for CxFV RT-qPCR was established. Quantitative standard curve analysis revealed that the lower detection limit of the RT-qPCR system is 100 copies/mu L. Moreover, RT-qPCR was used to detect CxFV viral RNA in mosquito pool samples. In conclusion, we established a real-time RT-PCR assay for CxFV detection, and this assay is more sensitive and efficient than general RT-PCR. This technology may be used to monitor changes in the environmental virus levels.展开更多
Objective:To identify unique immunogenic epitopes of Zika virus non-structural 1(NS1)antigen and produce immunoglobulin Y(IgY)for potential use in he diagnosis of of Zika virus infection.Methods:Immunogenic epitopes w...Objective:To identify unique immunogenic epitopes of Zika virus non-structural 1(NS1)antigen and produce immunoglobulin Y(IgY)for potential use in he diagnosis of of Zika virus infection.Methods:Immunogenic epitopes were identified using in silico B-cell epitope prediction.A synthetic peptide analog of the predicted epitope was used to induce antipeptide IgY production in hens which was purified using affinity chromatography.Presence of purified IgY and its binding specificity were performed by gel electrophoresis and ELISA,respectively.Results:Out of the nine continuous epitopes identified,the sequence at position 193-208(LKVREDYSLECDPAVI)was selected and used to produce anti-peptide IgY.The produced IgY was found to bind to the synthetic analog of the Zika virus NS1 immunogenic epitope but not to other flaviviruses and random peptides from other pathogens.Conclusions:In this study,we identified an immunogenic epitope unique to Zika virus that can be used to develop a serodiagnostic tool that specifically detect Zika virus infection.展开更多
Plus-strand RNA virus replication occurs in tight association with cytoplasmic host cell membranes. Both, viral and cellular factors cooperatively generate distinct organelle-like structures, designated viral replicat...Plus-strand RNA virus replication occurs in tight association with cytoplasmic host cell membranes. Both, viral and cellular factors cooperatively generate distinct organelle-like structures, designated viral replication factories. This compartmentalization allows coordination of the different steps of the viral replication cycle, highly efficient genome replication and protection of the viral RNA from cellular defense mechanisms. Electron tomography studies conducted during the last couple of years revealed the three dimensional structure of numerous plus-strand RNA virus replication compartments and highlight morphological analogies between different virus families. Based on the morphology of virusinduced membrane rearrangements, we propose two separate subclasses: the invaginated vesicle/spherule type and the double membrane vesicle type. This review discusses common themes and distinct differences in the architecture of plus-strand RNA virus-induced membrane alterations and summarizes recent progress that has been made in understanding the complex interplay between viral and co-opted cellular factors in biogenesis and maintenance of plus-strand RNA virus replication factories.展开更多
基金supported by National Key Research and Development Program of China(2016YFD0501102,2016YFD0500407)National Natural Science Foundation of China(31825025,32022082,32030107,32002268)+1 种基金Fundamental Research Funds for the Central Universities(2662018QD025)Natural Science Foundation of Hubei Province(2019CFA010)
文摘Flaviviruses are important arthropod-borne pathogens that represent an immense global health problem.Their unprecedented epidemic rate and unpredictable clinical features underscore an urgent need for antiviral interventions.Dehydroepiandrosterone(DHEA)is a natural occurring adrenal-derived steroid in the human body that has been associated in protection against various infections.In the present study,the plaque assay based primary screening was conducted on 32 synthetic derivatives of DHEA against Japanese encephalitis virus(JEV)to identify potent anti-flaviviral compounds.Based on primary screening,HAAS-AV3026 and HAAS-AV3027 were selected as hits from DHEA derivatives that exhibited strong antiviral activity against JEV(IC_(50)=2.13 and 1.98μmol/L,respectively)and Zika virus(ZIKV)(IC_(50)=3.73 and 3.42μmol/L,respectively).Mechanism study indicates that HAAS-AV3026 and HAAS-AV3027 do not exhibit inhibitory effect on flavivirus binding and entry process,while significantly inhibit flavivirus infection at the replication stage.Moreover,indirect immunofluorescence assay,Western blot analyses,and quantitative reverse transcription-PCR(qRT-PCR)revealed a potent antiviral activity of DHEA derivatives hits against JEV and ZIKV in terms of inhibition of viral infection,protein production,and viral RNA synthesis in Vero cells.Taken together,our results may provide a basis for the development of new antivirals against flaviviruses.
基金This work was supported by grants (to Guodong Liang) from National Science Foundation of China (No.30170046)
文摘The aim of this study is to explore the phylogenetic relationship of flaviviruses with the known viruses and to establish a rapid PCR-based method for the characterization of the flaviviruses. To this end, phylogenetic analysis of 25 different strains of flaviviruses was carried out on the basis of the full length genomic sequences as well as the sequences of the individual genes and their untranslated regions (UTRs). From this analysis and the extensive sequence alignment studies, a generic primer pair was identified for amplification of a highly conserved region in the NS5 gene, a molecular marker designed as NS5MM in this study, which was different from NS5 region used previously by other groups. This generic primer pair had been validated by using 22 different strains of flaviviruses in the present study. Furthermore, we have successfully applied this new approach to the rapid identification and characterization of 3 new strains of flaviviruses recently isolated in China.
文摘Flaviviruses are a genus of mostly arthropod-borne RNA viruses that cause a range of pathologies in humans.Basic knowledge on flaviviruses is rapidly expanding,partly due to their status as frequent emerging or re-emerging pathogens.Flaviviruses include the dengue,Zika,West Nile,tick-borne encephalitis and yellow fever viruses(DENV,ZIKV,WNV,TBEV and YFV,respectively).As is the case with other families of viruses,the success of productive infection of human cells by flaviviruses depends in part on the antiviral activity of a heterogeneous group of cellular antiviral proteins called restriction factors.Restriction factors are the effector proteins of the cell-autonomous innate response against viruses,an immune pathway that also includes virus sensors as well as intracellular and extracellular signal mediators such as type I interferons(IFN-I).In this review,I summarize recent progress toward the identification and characterization of flavivirus restriction factors.In particular,I focus on IFI6,Schlafen 11,FMRP,OAS-RNase L,RyDEN,members of the TRIM family of proteins(TRIM5α,TRIM19,TRIM56,TRIM69 and TRIM79α)and a new mechanism of action proposed for viperin.Recent and future studies on this topic will lead to a more complete picture of the flavivirus restrictome,defined as the ensemble of cellular factors with demonstrated anti-flaviviral activity.
基金Supported by The South Korea Health Technology R and D Project through the South Korea Health Industry Development Institute,Funded by the Ministry of Health and Welfare,South Korea,No.HF20C0020.
文摘Flaviviruses,which include globally impactful pathogens,such as West Nile virus,yellow fever virus,Zika virus,Japanese encephalitis virus,and dengue virus,contribute significantly to human infections.Despite the ongoing emergence and resurgence of flavivirus-mediated pathogenesis,the absence of specific therapeutic options remains a challenge in the prevention and treatment of flaviviral infections.Through the intricate processes of fusion,transcription,replication,and maturation,the complex interplay of viral and host metabolic interactions affects pathophysiology.Crucial interactions involve metabolic molecules,such as amino acids,glucose,fatty acids,and nucleotides,each playing a pivotal role in the replication and maturation of flaviviruses.These viral-host metabolic molecular interactions hijack and modulate the molecular mechanisms of host metabolism.A comprehensive understanding of these intricate metabolic pathways offers valuable insights,potentially unveiling novel targets for therapeutic interventions against flaviviral pathogenesis.This review emphasizes promising avenues for the development of therapeutic agents that target specific metabolic molecules,such as amino acids,glucose,fatty acids,and nucleotides,which interact with flavivirus replication and are closely linked to the modulation of host metabolism.The clinical limitations of current drugs have prompted the development of new inhibitory strategies for flaviviruses based on an understanding of the molecular interactions between the virus and the host.
基金supported by the Spanish Ministry of Science and Innovation AEI under grant PID2020-119195RJ-I00(to NJO).
文摘Flaviviruses affect the lives of millions of people in endemic regions and also have the potential to impact nonendemic areas.Factors such as climate change,global warming,deforestation,and increased travel and trade are linked to the spread of flaviviruses into new habitats and host species.Given the absence of specific treatments and the limited availability of vaccines,it is imperative to understand the biology of flaviviruses and develop rapid and sensitive diagnostic tests.These measures are essential for preventing the transmission of these potentially life-threatening pathogens.Flavivirus infections are mainly diagnosed using conventional methods.However,these techniques present several drawbacks,including high expenses,time-consuming procedures,and the need for skilled professionals.The search for fast,easy-to-use,and affordable alternative techniques as a feasible solution for developing countries is leading to the search for new methods in the diagnosis of flavivi-ruses,such as biosensors.This review provides a comprehensive overview of different biosensor detection strategies for flaviviruses and describes recent advances in diagnostic technologies.Finally,we explore their future prospects and potential applications in pathogen detection.This review serves as a valuable resource to understand advances in ongoing research into new biosensor-based diagnostic methods for flaviviruses.
基金Supported by the Permanecer Program(part of the actions of the Office of Affirmative Actions)Education and Diversity of the Dean of Student Assistance at the Federal University of Bahia(UFBA)and CNPq Research Productivity Fellow.
文摘Arboviral diseases are viral infections transmitted to humans through the bites of arthropods,such as mosquitoes,often causing a variety of pathologies associated with high levels of morbidity and mortality.Over the past decades,these infections have proven to be a significant challenge to health systems worldwide,particularly following the considerable geographic expansion of the dengue virus(DENV)and its most recent outbreak in Latin America as well as the difficult-tocontrol outbreaks of yellow fever virus(YFV),chikungunya virus(CHIKV),and Zika virus(ZIKV),leaving behind a substantial portion of the population with complications related to these infections.Currently,the world is experiencing a period of intense globalization,which,combined with global warming,directly contributes to wider dissemination of arbovirus vectors across the globe.Consequently,all continents remain on high alert for potential new outbreaks.Thus,this review aims to provide a comprehensive understanding of the pathogenesis of the four main arboviruses today(DENV,ZIKV,YFV,and CHIKV)discussing their viral characteristics,immune responses,and mechanisms of viral evasion,as well as important clinical aspects for patient management.This includes associated symptoms,laboratory tests,treatments,existing or developing vaccines and the main associated complications,thus integrating a broad historical,scientific and clinical approach.
基金funded by the Portuguese Foundation for Science and Technology(FCT)sup-ported by the projects UIDB/00772/2020(https://doi.org/10.54499/UIDB/00772/2020)。
文摘Emerging infectious diseases are a major threat to biodiversity and an important public health issue.Flaviviruses are the cause of several emerging vector-borne zoonotic arboviruses whose distribution is currently increasing in Europe.The evidence that West Nile virus(WNV)circulates in resident and migratory species has implications for both animal and public health and should therefore be studied in depth.USUTU(USUV),Bagaza(BAGV)and tick-borne encephalitis virus(TBEV)are other viruses that are beginning to spread more widely.An integrated surveillance program,namely in birds,is essential for reducing the risk of infection in human populations within the One Health principles.In the present study,wild birds admitted to wildlife rehabilitation centers in Portugal were sampled.Two hundred eight blood samples were assayed serologically for antibodies to flaviviruses by using a commercial ELISA kit.An over-all seroprevalence of 19.6%(95%confidence interval[CI]:13.7-26.7%)was observed.Antibodies against flaviviruses were detected in 13(35.1%)different species of wild birds.Accipitriformes(26.7%;95%CI:18.5-36.2%)and Strigi-formes(26.7%;95%CI:14.6-42.0%)were the orders with the highest seroprevalence rates recorded.There were no statistically significant differences(p=0.725)between the geographical regions(NUTSⅡ)studied,but a statistically significant difference(p=0.017)was found between sex(male:34.4%;female:4.8%).A higher seroprevalence was detected in adults(32.1%)than in juvenile birds(9.3%)(p=0.014),and age was considered a risk factor for flavivirus infection in wild birds(odds ratio 1.4;95%CI:0.5-4.0).More epidemiological studies are needed in Portugal since the actual spread of the genus Flavivirus throughout the country is unknown.
文摘BACKGROUND In tropical Asia,arbovirus-induced encephalitis continues to be a serious public health issue.Encephalitis is caused by wide range of neurotropic pathogens,and flaviviruses are one of the main causative agents in the area.Sri Lanka reports a considerable number of central nervous system infections annually.Both dengue and Japanese encephalitis are endemic,and cases of Zika and West Nile virus infections were reported occasionally in Sri Lanka.Although reported number of Japanese encephalitis cases has reduced in the past,aetiological diagnosis in majority of encephalitis cases is still unknown.AIM To detect dengue virus(DENV)infections in individuals in the central region of Sri Lanka who were clinically suspected of having encephalitis.METHODS A retrospective observational analysis was conducted on 99 cerebrospinal fluid samples received to a virology laboratory from patients in the central part of Sri Lanka who were clinically suspected of having encephalitis.Samples were analyzed using reverse transcriptase polymerase chain reaction(RT-PCR)with universal flavivirus primers to detect flaviviral RNA followed by DENV serotyping real-time RT-PCR,and an immunoglobulin M(IgM)detection enzyme-linked immunosorbent assay to detect IgM antibodies indicative of a possible recent DENV infection.RESULTS DENV aetiology was detected in 6(6.06%)cerebrospinal fluid samples,and all were confirmed as DENV infections.A single positive result(1.01%)was yielded through RT-PCR and was identified as DENV serotype 3.Serology testing detected 05(5.05%)anti-dengue IgM positives and further investigation indicated probable DENV aetiology.Among positives 02(33.33%)were children(aged less than 14 years),and rest were adults.CONCLUSION These findings underscore the presence of DENV-associated central nervous system infections and highlight the need for broader surveillance and more advanced diagnostic approaches in the future.
基金funded by National Natural Science Foundation of China(92578123)Shenzhen High-level Hospital Construction Fund(23250G1001)+3 种基金the Sanming Project of Medicine in Shenzhen(SZSM202311033)National Key Research and Development Program of China(2023YFC2606004)National Natural Science Foundation of China(32501262)Beijing Institute of Technology Research Fund Program for Young Scholars(6120220072).
文摘Dengue virus(DENV)is a mosquito-borne pathogen responsible for a spectrum of illnesses,including dengue fever,dengue hemorrhagic fever,and dengue shock syndrome.Nearly half of the global population is at risk of DENV infection,making it a pressing public health issue worldwide.The limited cross-protection among the four DENV serotypes(DENV1-4)and the phenomenon of antibody-dependent enhancement(ADE)have posed significant challenges to the development of effective dengue vaccines.Furthermore,there are currently no specific antiviral treatments available.This review provides an overview of DENV's key characteristics,clinical manifestations,and recent advancements in antiviral drug development-including the repurposing of approved drugs,peptidebased antiviral agents,therapeutic antibodies,natural products with antiviral potential,and host factor inhibitors-aiming to offer critical insights to inform strategies for managing and preventing dengue outbreaks.
基金the“Metropolitan Mosquitoes Project”funded by the Swedish Research Council for Environment,Agricultural Sciences and Spatial Planning(Formas,grant number 2016-00364).
文摘Dengue virus(DENV)is a positive-sense single-stranded RNA virus belonging to the genus Flavivirus within the Flaviviridae family.Four serotypes,DENV 1-4,are distributed globally[1].Hanoi metropolitan city is an endemic hotspot for DENV transmission in Vietnam[2,3].The largest outbreak occurred in 2017,with more than 36000 cases and 7 deaths reported,causing by all four serotypes with the predominance of DENV1,following by DENV2[4,5].During the following dengue season,we collected 390 blood and serum samples from 197 hospitalized patients in a national hospital in Hanoi city,Northern Vietnam to identify the circulating DENV serotypes responsible for the 2018-2019 outbreak.
文摘There are presently no in-depth published neuropsychological studies of West Nile Virus (WNV) encephalitis patients that have been well-correlated with high resolution structural MRI. In this study a middleaged male who developed West Nile Virus encephalitis five years previously was examined three times over a two year period. We examined him with the Wechsler Adult Intelligence Scales—Fourth Edition and the Wechsler Memory Scale—Fourth Edition (WAIS-IV/WMS-IV) and Advanced Clinical Solutions battery supplemented by tests of attention, executive, motor and sensory functions. Neuroradiological imaging revealed hypodensities within the left hippocampus in the axial and coronal planes with T2-FLAIR MRI. The man was previously high functioning and although he had prior history of well-controlled epilepsy it seems unlikely that the epilepsy could fully account for the neuropathological changes. The patient had previously completed a demanding six year double science degree program before he became ill with WNV and he had been a successful manager and director of a research company. Delayed auditory memory scores were at least two standard deviation units below age expected levels and semantic fluency and Booklet Category Tests of executive function were also in the impaired range. Moreover the illness onset profile of muscle weakness, extreme fatigue, memory complaints as well as inability to carry out research projects involving planning on the job were highly consistent with WNV encephalitis. If the memory and executive function deficits had been premorbid manifestations of epilepsy it is unlikely he would have attained the levels he did educationally and occupationally. This left hippocampal lesion is characteristic of other encephalitic viral infections such as herpes simplex virus. To our knowledge this is the first lateralized WNV encephalitis medial temporal lobe patient in the published literature.
基金supported by Collaborative Research Grant (KLMVI-OP-201904) of CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciencesthe starting Grant of Institut Pasteur of Shanghai (1185170000), Chinese Academy of Sciences
文摘The family of flaviviruses is one of the most medically important groups of emerging arthropod-borne viruses. Host cell cytoskeletons have been reported to have close contact with flaviviruses during virus entry, intracellular transport, replication, and egress process, although many detailed mechanisms are still unclear. This article provides a brief overview of the function of the most prominent flaviviruses-induced or-hijacked cytoskeletal structures including actin, microtubules and intermediate filaments, mainly focus on infection by dengue virus, Zika virus and West Nile virus. We suggest that virus interaction with host cytoskeleton to be an interesting area of future research.
基金supported by grants from the National Natural Science Foundation of China (81372935,81271839,81401676 and 81301435)
文摘Dengue virus(DENV) has four distinct serotypes. DENV infection can result in classic dengue fever and life-threatening dengue hemorrhagic fever/dengue shock syndrome. In recent decades, DENV infection has become an important public health concern in epidemic-prone areas. Vaccination is the most effective measure to prevent and control viral infections. However, several challenges impede the development of effective DENV vaccines, such as the lack of suitable animal models and the antibody-dependent enhancement phenomenon. Although no licensed DENV vaccine is available, significant progress has been made. This review summarizes candidate DENV vaccines from recent investigations.
基金supported by grants(AI094335) from the National Institute of Health and from the Wadsworth Center Scientific Interaction Group
文摘Many flaviviruses are significant human pathogens causing considerable disease burdens,including encephalitis and hemorrhagic fever,in the regions in which they are endemic.A paucity of treatments for flaviviral infections has driven interest in drug development targeting proteins essential to flavivirus replication,such as the viral protease.During viral replication,the flavivirus genome is translated as a single polyprotein precursor,which must be cleaved into individual proteins by a complex of the viral protease,NS3,and its cofactor,NS2B.Because this cleavage is an obligate step of the viral life-cycle,the flavivirus protease is an attractive target for antiviral drug development.In this review,we will survey recent drug development studies targeting the NS3 active site,as well as studies targeting an NS2B/NS3interaction site determined from flavivirus protease crystal structures.
基金supported by the National Natural Science Foundation of China (31172345)the Jiangsu Provincial Agricultural Science and Technology InnovationFoundation, China (cx(11)4039)
文摘In order to establish double antibody sandwich enzyme-linked immunosorbent assay （DAS-ELISA） for detection of duck or goose flavivirus, polyclonal antibody against the flavivirus strain JS804 in geese and monoclonal antibody against the E protein of flavivirus strain JS804 in geese were used as the capture antibody and detection antibody, respectively. The optimal dilution of the capture antibody and detecting antibody capable of detecting the flavivirus strain JS804 in geese were 1：3 200 and 1：160 in the check-board titration, respectively. The reaction time of sample was 1 h, and the optimal working dilution of HRP-labeled goat-anti-mouse IgG was 1：10 000. The positive standard value was 0.247 （OD450.m）. The geese flavivirus could be detected at a minimal concentration of 1.875 μg mL^-1. The ELISA had no cross-reaction with Newcastle disease virus （NDV）, Avian influenza virus （AIV）, Infectious bronchitis virus （IBV）, Infectious bursal disease virus （IBDV）, Duck hepatitis virus （DHV）, and Gosling plague virus （GPV）. Twenty clinical samples were detected by the DAS-ELISA and RT-PCR respectively, with the agreement rate of 75%. The results revealed that the DAS-ELISA possessed favorable specificity and higher sensitivity, indicating a suitable method for rapid detection of the duck or goose flavivirus.
基金supported by National Institute of Health grants U01 AI061193 and U54-AI057158 (Northeast Biodefense Center).
文摘Many flaviviruses are emerging and reemerging pathogens, such as West Nile virus （WNV）, dengue virus （DENV）, yellow fever virus （YFV）, and Japanese encephalitis virus. Serological assay is the dominant method for diagnosis of flavivirus infections in human. Because antibodies generated during flavivirus infections cross-react with other flavivirus members, plaque reduction neutralization test （PRNT） is the only available assay to determine the infecting flavivirus type. Since PRNT requires culturing raw viruses, it must be performed in biosafety levet-3 or level-4 containment for many flaviviruses, and takes more than ten days to complete. To overcome these problems, we have developed flavivirus viral-like particles （VLPs） that could be used to replace raw viruses in the neutralization assay. The VLPs were prepared by trans packaging a luciferase-reporting replicon with viral structural proteins. This novel assay involves three simple steps： （i） VLPs from a panel of flaviviruses are incubated with flavivirus-infected sera at 37℃ for 1 h; （ii）the neutralized VLPs are used to infect Vero cells; and （iii） the infected cells are measured for luciferase activities at 22 h post-infection. The virus type whose VLP is most efficiently neutralized by the serum specimen （as quantified by the luciferase activities） is the etiologic agent. As a proof-of-concept, we show that a WNV-infected mouse serum neutralized the WNV VLP more efficiently and selectively than the DENV and YFV VLPs. Our results demonstrate that the VLP neutralization assay maintains the ＂gold standard＂ of the classic PRNT; importantly, it shortens the assay time from 〉10 days to 〈1 day, and can be performed in biosafety level-2 facility.
文摘Dengue is a common pathogenic disease often proving fatal,more commonly affecting the tropics.Aedes mosquito is the vector for this disease,and outbreaks of dengue often cause mass damage to life.The current review is an effort to present an insight into the causes,etiology,symptoms,transmission,diagnosis,major organs affected,mitigation and line of treatment of this disease with special emphasis on dings of natural origin.The disease has a potential to spread as an endemic,often claiming several lives and thus requires concerted efforts to work out better treatment options.Traditional medicine offers an alternative solution and could be explored as a safer treatment option.Development of a successful vaccine and immunization technique largely remains a challenge and a better antiviral approach needs to be worked out to complement the supportive therapy.No single synthetic molecule has found to be wholly effective enough to offer curative control and the line of treatment mostly utilizes a combination of fluid replacement and antipyretics-analgesics like molecules to provide symptomatic relief.
基金supported by grants from the Development Grant of State Key Laboratory of Infectious Disease Prevention and Control(2012SKLID204,2015SKLID505)the Ministry of Science and Technology of People’s Republic of China(No.2013ZX10004101)
文摘Based on the Culex flavivirus (CxFV) E gene sequences in GenBank, CxFV-specific primers and probes were designed for real-time reverse transcription-polymerase chain reaction (RT-qPCR). The specificity test revealed that CxFV could be detected using RT-qPCR with the specific CxFV primers and probes; other species of arboviruses were not detected. The stability test demonstrated a coefficient of variation of <1.5%. A quantitative standard curve for CxFV RT-qPCR was established. Quantitative standard curve analysis revealed that the lower detection limit of the RT-qPCR system is 100 copies/mu L. Moreover, RT-qPCR was used to detect CxFV viral RNA in mosquito pool samples. In conclusion, we established a real-time RT-PCR assay for CxFV detection, and this assay is more sensitive and efficient than general RT-PCR. This technology may be used to monitor changes in the environmental virus levels.
文摘Objective:To identify unique immunogenic epitopes of Zika virus non-structural 1(NS1)antigen and produce immunoglobulin Y(IgY)for potential use in he diagnosis of of Zika virus infection.Methods:Immunogenic epitopes were identified using in silico B-cell epitope prediction.A synthetic peptide analog of the predicted epitope was used to induce antipeptide IgY production in hens which was purified using affinity chromatography.Presence of purified IgY and its binding specificity were performed by gel electrophoresis and ELISA,respectively.Results:Out of the nine continuous epitopes identified,the sequence at position 193-208(LKVREDYSLECDPAVI)was selected and used to produce anti-peptide IgY.The produced IgY was found to bind to the synthetic analog of the Zika virus NS1 immunogenic epitope but not to other flaviviruses and random peptides from other pathogens.Conclusions:In this study,we identified an immunogenic epitope unique to Zika virus that can be used to develop a serodiagnostic tool that specifically detect Zika virus infection.
基金Supported by The DFG,SFB638,TP A5 and SFB/TRR83,TP 13
文摘Plus-strand RNA virus replication occurs in tight association with cytoplasmic host cell membranes. Both, viral and cellular factors cooperatively generate distinct organelle-like structures, designated viral replication factories. This compartmentalization allows coordination of the different steps of the viral replication cycle, highly efficient genome replication and protection of the viral RNA from cellular defense mechanisms. Electron tomography studies conducted during the last couple of years revealed the three dimensional structure of numerous plus-strand RNA virus replication compartments and highlight morphological analogies between different virus families. Based on the morphology of virusinduced membrane rearrangements, we propose two separate subclasses: the invaginated vesicle/spherule type and the double membrane vesicle type. This review discusses common themes and distinct differences in the architecture of plus-strand RNA virus-induced membrane alterations and summarizes recent progress that has been made in understanding the complex interplay between viral and co-opted cellular factors in biogenesis and maintenance of plus-strand RNA virus replication factories.
