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systems to establish bunyavirus genome replication in the absence of transcription.the l polymerase of bunyaviruses replicates and transcribes the viral genome. while replication products are faithful copies of the uncapped genomic rna, transcription products contain capped 5' extensions which had been cleaved from host cell mrnas. for la crosse virus (lacv; genus orthobunyavirus), the nuclease responsible for host cell mrna cleavage is located at the n terminus of the l protein, with an active site of five conserved amino acids (h34, d52, d79, d92, and k94) surrounding two mn ...201323698297
severe fever with thrombocytopenia virus glycoproteins are targeted by neutralizing antibodies and can use dc-sign as a receptor for ph-dependent entry into human and animal cell lines.severe fever with thrombocytopenia syndrome virus (sftsv) is a novel bunyavirus that recently emerged in china. infection with sftsv is associated with case-fatality rates of up to 30%, and neither antivirals nor vaccines are available at present. development of antiviral strategies requires the elucidation of virus-host cell interactions. here, we analyzed host cell entry of sftsv. employing lentiviral and rhabdoviral vectors, we found that the gn/gc glycoproteins (gn/gc) of sftsv mediate entry ...201323388721
segmented negative-strand rna viruses and rig-i: divide (your genome) and rule.the group of negative-stranded rna viruses (nsvs) with a segmented genome comprises pathogens like influenza virus (eight segments), rift valley fever virus and hantavirus (three segments), or lassa virus (two segments). partitioning the genome allows rapid evolution of new strains by reassortment. each segment carries a short double-stranded (ds) 'panhandle' structure which serves as promoter. similar dsrna structures, however, represent the optimal ligand for rig-i, a cytoplasmic pathogen sens ...201424930021
seroprevalence of rift valley fever and lumpy skin disease in african buffalo (syncerus caffer) in the kruger national park and hluhluwe-imfolozi park, south africa.rift valley fever and lumpy skin disease are transboundary viral diseases endemic in africa and some parts of the middle east, but with increasing potential for global emergence. wild ruminants, such as the african buffalo (syncerus caffer), are thought to play a role in the epidemiology of these diseases. this study sought to expand the understanding of the role of buffalo in the maintenance of rift valley fever virus (rvfv) and lumpy skin disease virus (lsdv) by determining seroprevalence to t ...201425686252
seroprevalence of rift valley fever and lumpy skin disease in african buffalo (<i>syncerus caffer</i>) in the kruger national park and hluhluwe-imfolozi park, south africa.rift valley fever and lumpy skin disease are transboundary viral diseases endemic in africa and some parts of the middle east, but with increasing potential for global emergence. wild ruminants, such as the african buffalo (syncerus caffer), are thought to play a role in the epidemiology of these diseases. this study sought to expand the understanding of the role of buffalo in the maintenance of rift valley fever virus (rvfv) and lumpy skin disease virus (lsdv) by determining seroprevalence to t ...201428235305
efficacy assessment of an mva vectored rift valley fever vaccine in lambs.the present study has evaluated the protection conferred by a single subcutaneous dose of a modified vaccinia virus ankara (mva) vectored vaccine encoding the rift valley fever virus (rvfv) glycoproteins gn and gc in lambs. three groups of six to seven lambs were immunized as follows: one group received the vaccine (termed rmva-gngc), a second group received an mva vector (vector control) and a third group received saline solution (non-vaccinated control). fourteen days later, all animals were s ...201424933081
a single immunization with mva expressing gngc glycoproteins promotes epitope-specific cd8+-t cell activation and protects immune-competent mice against a lethal rvfv infection.rift valley fever virus (rvfv) is a mosquito-borne pathogen causing an important disease in ruminants often transmitted to humans after epizootic outbreaks in african and arabian countries. to help combat the spread of the disease, prophylactic measures need to be developed and/or improved.201323875044
paramyxovirus-based production of rift valley fever virus replicon particles.replicon-particle-based vaccines combine the efficacy of live-attenuated vaccines with the safety of inactivated or subunit vaccines. recently, we developed rift valley fever virus (rvfv) replicon particles, also known as nonspreading rvfv (nsr), and demonstrated that a single vaccination with these particles can confer sterile immunity in target animals. nsr particles can be produced by transfection of replicon cells, which stably maintain replicating rvfv s and l genome segments, with an expre ...201425209808
efficacy of three candidate rift valley fever vaccines in sheep.rift valley fever virus (rvfv) is a mosquito-transmitted bunyavirus that causes high morbidity and mortality among ruminants and humans. the virus is endemic to the african continent and the arabian peninsula and continues to spread into new areas. the explosive nature of rvf outbreaks requires that vaccines provide swift protection after a single vaccination. we recently developed several candidate vaccines and here report their efficacy in lambs within three weeks after a single vaccination. t ...201222449427
[the concept of emerging viral diseases: what risk for reunion island?].in reunion island, the risk of emerging infectious diseases lies mainly in several viral zoonoses: west nile fever, sindbis virus, nipah virus, wesselsbron virus, rift valley fever and japanese encephalitis. there morbidity and consequences are more or less important but they all have a non-negligible epidemic potential, so they have to be monitored. indeed, the struggle against these emerging infectious diseases requires an early detection of the cases, thus a surveillance system capable of det ...201323765703
serological evidence for the circulation of rift valley fever virus in domestic small ruminants in southern gabon.rift valley fever (rvf) is a zoonotic disease, which caused several epidemics in humans in many countries of africa. using an inhibition enzyme-linked immunosorbent assay (elisa), real-time reverse transcription pcr, and nested one-step reverse transcription pcr, we conducted a cross-sectional study in populations of sheep and goats from the mongo county in 2014 to determine the circulation of the rift valley fever virus (rvfv) in small ruminants from this area. from a total of 201 small ruminan ...201728387600
seroprevalence of rift valley fever virus in livestock during inter-epidemic period in egypt, 2014/15.rift valley fever virus (rvfv) caused several outbreaks throughout the african continent and the arabian peninsula posing significant threat to human and animal health. in egypt the first and most important rift valley fever epidemic occurred during 1977/78 with a multitude of infected humans and huge economic losses in livestock. after this major outbreak, rvf epidemics re-occurred in irregular intervals between 1993 and 2003. seroprevalence of anti-rvfv antibodies in livestock during inter-epi ...201728381251
seroprevalence of rift valley fever in cattle along the akagera-nyabarongo rivers, rwanda.rift valley fever (rvf) virus is caused by a zoonotic arbovirus that is endemic to eastern and southern africa. it has also been reported in west and north africa, madagascar and the arabian peninsula. the virus is transmitted by mosquitoes, but people can also become infected while handling blood or other body fluids of animals and humans with rvf. in 2007, there was a large outbreak of rvf in kenya, tanzania, sudan and somalia. outbreaks were also reported in south africa in 2008-2011. the epi ...201728240033
distribution and abundance of key vectors of rift valley fever and other arboviruses in two ecologically distinct counties in kenya.rift valley fever (rvf) is a mosquito-borne viral zoonosis of ruminants and humans that causes outbreaks in africa and the arabian peninsula with significant public health and economic consequences. humans become infected through mosquito bites and contact with infected livestock. the virus is maintained between outbreaks through vertically infected eggs of the primary vectors of aedes species which emerge following rains with extensive flooding. infected female mosquitoes initiate transmission ...201728212379
exploring genetic variation in haplotypes of the filariasis vector culex quinquefasciatus (diptera: culicidae) through dna barcoding.culex quinquefasciatus (diptera: culicidae) is a vector of many pathogens and parasites of humans, as well as domestic and wild animals. in urban and semi-urban asian countries, cx. quinquefasciatus is a main vector of nematodes causing lymphatic filariasis. in the african region, it vectors the rift valley fever virus, while in the usa it transmits west nile, st. louis encephalitis and western equine encephalitis virus. in this study, dna barcoding was used to explore the genetic variation of c ...201728126462
evaluation of positive rift valley fever virus formalin-fixed paraffin embedded samples as a source of sequence data for retrospective phylogenetic analysis.rift valley fever (rvf), caused by an arthropod borne phlebovirus in the family bunyaviridae, is a haemorrhagic disease that affects ruminants and humans. due to the zoonotic nature of the virus, a biosafety level 3 laboratory is required for isolation of the virus. fresh and frozen samples are the preferred sample type for isolation and acquisition of sequence data. however, these samples are scarce in addition to posing a health risk to laboratory personnel. archived formalin-fixed, paraffin-e ...201728118988
rift valley fever virus infections in egyptian cattle and their prevention.rift valley fever virus (rvfv) causes consistently severe outbreaks with high public health impacts and economic losses in livestock in many african countries and has also been introduced to saudi arabia and yemen. egypt with its four large outbreaks in the last 40 years represents the northernmost endemic area of rvfv. the purpose of this study was to provide an insight into the current anti-rvfv antibody status in immunized as well as non-immunized dairy cattle from the nile delta of egypt. du ...201728116860
mosquitoes (diptera: culicidae) in mauritania: a review of their biodiversity, distribution and medical importance.although mosquitoes (diptera: culicidae) are important disease vectors, information on their biodiversity in mauritania is scarce and very dispersed in the literature. data from the scientific literature gathered in the country from 1948 to 2016 were collected and analyzed. overall 51 culicid species comprising 17 anopheles spp., 14 aedes spp., 18 culex spp. and two mansonia spp. have been described in mauritania among which anopheles arabiensis, aedes vexans, culex poicilipes and culex antennat ...201728103955
drivers of rift valley fever epidemics in madagascar.rift valley fever (rvf) is a vector-borne viral disease widespread in africa. the primary cycle involves mosquitoes and wild and domestic ruminant hosts. humans are usually contaminated after contact with infected ruminants. as many environmental, agricultural, epidemiological, and anthropogenic factors are implicated in rvf spread, the multidisciplinary one health approach was needed to identify the drivers of rvf epidemics in madagascar. we examined the environmental patterns associated with t ...201728096420
reconstruction of rift valley fever transmission dynamics in madagascar: estimation of force of infection from seroprevalence surveys using bayesian modelling.the force of infection (foi) is one of the key parameters describing the dynamics of transmission of vector-borne diseases. following the occurrence of two major outbreaks of rift valley fever (rvf) in madagascar in 1990-91 and 2008-09, recent studies suggest that the pattern of rvf virus (rvfv) transmission differed among the four main eco-regions (east, highlands, north-west and south-west). using bayesian hierarchical models fitted to serological data from cattle of known age collected during ...201728051125
vector-borne pathogen and host evolution in a structured immuno-epidemiological system.vector-borne disease transmission is a common dissemination mode used by many pathogens to spread in a host population. similar to directly transmitted diseases, the within-host interaction of a vector-borne pathogen and a host's immune system influences the pathogen's transmission potential between hosts via vectors. yet there are few theoretical studies on virulence-transmission trade-offs and evolution in vector-borne pathogen-host systems. here, we consider an immuno-epidemiological model th ...201728032207
serological and genomic evidence of rift valley fever virus during inter-epidemic periods in mauritania.rift valley fever virus (rvfv) is an emerging pathogen of major concern throughout africa and the arabian peninsula, affecting both livestock and humans. in the past recurrent epidemics were reported in mauritania and studies focused on the analysis of samples from affected populations during acute outbreaks. to verify characteristics and presence of rvfv during non-epidemic periods we implemented a multi-stage serological and molecular analysis. serum samples of small ruminants, cattle and came ...201728029091
vaccination of alpacas against rift valley fever virus: safety, immunogenicity and pathogenicity of mp-12 vaccine.rift valley fever (rvf) is an emerging zoonosis of major public health concern in africa and arabia. previous outbreaks attributed camelids a significant role in the epidemiology of rift valley fever virus (rvfv), making them an important target species for vaccination. using three alpacas as model-organisms for dromedary camels, the safety, immunogenicity and pathogenicity of the mp-12 vaccine were evaluated in this study. to compare both acute and subacute effects, animals were euthanized at 3 ...201728012779
effects of irrigation and rainfall on the population dynamics of rift valley fever and other arbovirus mosquito vectors in the epidemic-prone tana river county, kenya.rift valley fever (rvf) is a mosquito-borne viral zoonosis that is found in most regions of sub-saharan africa, and it affects humans, livestock, and some wild ungulates. outbreaks are precipitated by an abundance of mosquito vectors associated with heavy persistent rainfall with flooding. we determined the impact of flood-irrigation farming and the effect of environmental parameters on the ecology and densities of primary and secondary vectors of the rvf virus (rvfv) in an rvf-epidemic hotspot ...201628011732
synthesis and in vitro antiviral evaluation of 4-substituted 3,4-dihydropyrimidinones.a series of 4-substituted 3,4-dihydropyrimidine-2-ones (dhpm) was synthesized, characterized by ir, (1)h nmr, (13)c nmr and hrms spectra. the compounds were evaluated in vitro for their antiviral activity against a broad range of dna and rna viruses, along with assessment for potential cytotoxicity in diverse mammalian cell lines. compound 4m, which possesses a long lipophilic side chain, was found to be a potent and selective inhibitor of punta toro virus, a member of the bunyaviridae. for rift ...201727979594
modelling vaccination strategies against rift valley fever in livestock in kenya.the impacts of vaccination on the transmission of rift valley fever virus (rvfv) have not been evaluated. we have developed a rvfv transmission model comprising two hosts-cattle as a separate host and sheep and goats as one combined host (herein after referred to as sheep)-and two vectors-aedes species (spp) and culex spp-and used it to predict the impacts of: (1) reactive vaccination implemented at various levels of coverage at pre-determined time points, (2) targeted vaccination involving eith ...201627973528
short interfering rna inhibits rift valley fever virus replication and degradation of protein kinase r in human cells.rift valley fever virus (rvfv) is a mosquito-borne zoonotic pathogen causing severe outbreaks in humans and livestock in sub-saharan africa and the arabian peninsula. human infections are characterized by fever, sometimes leading to encephalitis, retinitis, hemorrhagic fever, and occasionally death. there are currently no fully licensed vaccines or effective therapies for human use. gene silencing mediated by double-stranded short interfering rna (sirna) is a sequence-specific, highly conserved ...201627933051
seroepidemiological survey of rift valley fever virus in ruminants in garissa, kenya.rift valley fever (rvf) is a vector-borne zoonotic disease caused by phlebovirus in the family bunyaviridae. in kenya, major outbreaks occurred in 1997-1998 and 2006-2007 leading to human deaths, huge economic losses because of livestock morbidity, mortality, and restrictions on livestock trade.201727929928
rift valley fever outbreak in livestock, mozambique, 2014.in early 2014, abortions and death of ruminants were reported on farms in maputo and gaza provinces, mozambique. serologic analysis and quantitative and conventional reverse transcription pcr confirmed the presence of rift valley fever virus. the viruses belonged to lineage c, which is prevalent among rift valley fever viruses in southern africa.201627869589
severe human illness caused by rift valley fever virus in mauritania, 2015.rift valley fever epizootics are characterized by numerous abortions and mortality among young animals. in humans, the illness is usually characterized by a mild self-limited febrile illness, which could progress to more serious complications.objectives. the aim of the present prospective study was to describe severe clinical signs and symptoms of rift valley fever in southern mauritania.201627844026
rift valley fever virus imported into china from angola. 201627788984
mouse model for the rift valley fever virus mp12 strain infection.rift valley fever virus (rvfv), a category a pathogen and select agent, is the causative agent of rift valley fever. to date, no fully licensed vaccine is available in the u.s. for human or animal use and effective antiviral drugs have not been identified. the rvfv mp12 strain is conditionally licensed for use for veterinary purposes in the u.s. which was excluded from the select agent rule of health and human services and the u.s. department of agriculture. the mp12 vaccine strain is commonly u ...201627771072
identifying areas suitable for the occurrence of rift valley fever in north africa: implications for surveillance.rift valley fever (rvf) is a vector-borne zoonotic disease that has caused widespread outbreaks throughout africa and the arabian peninsula, with serious consequences for livestock-based economies and public health. although there have never been any reports of rvf in morocco, algeria, tunisia and libya, it is a priority disease in the maghreb, due to the threat of introduction of the virus through transboundary livestock movements or infected mosquito vectors. however, the implementation of sur ...201625655790
mechanistic insight into the host transcription inhibition function of rift valley fever virus nss and its importance in virulence.rift valley fever virus (rvfv), a member of the genus phlebovirus within the family bunyaviridae, causes periodic outbreaks in livestocks and humans in countries of the african continent and middle east. rvfv nss protein, a nonstructural protein, is a major virulence factor that exhibits several important biological properties. these include suppression of general transcription, inhibition of ifn-β promoter induction and degradation of double-stranded rna-dependent protein kinase r. although eac ...201627711108
rift valley fever trasmission dynamics described by compartmental models.rift valley fever (rvf) is one of the most important zoonotic transboundary animal diseases able to cross international borders and cause devastating effect on animal health and food security. climate changes and the presence of competent vectors in the most of the current rvf-free temperate countries strongly support the inclusion of rvf virus (rvfv) among the most significant emerging viral threats for public and animal health. the transmission of rvfv is driven by complex eco-climatic factors ...201627707507
traditional herbal remedies and dietary spices from cameroon as novel sources of larvicides against filariasis mosquitoes?in cameroon, many dietary spices are used by traditional healers to cure several diseases such as cancer and microbial infections. aframomum daniellii, dichrostachys cinerea and echinops giganteus are cameroonian spices widely used as flavourings and as food additives. moreover, they are traditionally herbal remedies employed to treat several diseases, as well as to control populations of insect pests. in this research, we analysed the chemical composition of a. daniellii, d. cinerea and e. giga ...201627679452
spatial heterogeneity of habitat suitability for rift valley fever occurrence in tanzania: an ecological niche modelling approach.despite the long history of rift valley fever (rvf) in tanzania, extent of its suitable habitat in the country remains unclear. in this study we investigated potential effects of temperature, precipitation, elevation, soil type, livestock density, rainfall pattern, proximity to wild animals, protected areas and forest on the habitat suitability for rvf occurrence in tanzania.201627654268
structural and practical identifiability issues of immuno-epidemiological vector-host models with application to rift valley fever.in this article, we discuss the structural and practical identifiability of a nested immuno-epidemiological model of arbovirus diseases, where host-vector transmission rate, host recovery, and disease-induced death rates are governed by the within-host immune system. we incorporate the newest ideas and the most up-to-date features of numerical methods to fit multi-scale models to multi-scale data. for an immunological model, we use rift valley fever virus (rvfv) time-series data obtained from li ...201627651156
[severe hemorrhagic forms of rift valley fever: about 5 cases].rift valley fever (rvf) is an arbovirus caused by an rna virus belonging to family bunyaviridae (genus phlebovirus). it is a zoonosis that primarily affects animals but it also has the capacity to infect humans, either by handling meat, runts of sick animals or, indirectly, by the bite of infected mosquitoes (aedes sp, anopheles sp, culex sp). in most cases, rvf infection in humans is asymptomatic, but it can also manifest as moderate febrile syndrome with a favorable outcome. however, some pati ...201627642413
single-molecule fish reveals non-selective packaging of rift valley fever virus genome segments.the bunyavirus genome comprises a small (s), medium (m), and large (l) rna segment of negative polarity. although genome segmentation confers evolutionary advantages by enabling genome reassortment events with related viruses, genome segmentation also complicates genome replication and packaging. accumulating evidence suggests that genomes of viruses with eight or more genome segments are incorporated into virions by highly selective processes. remarkably, little is known about the genome packag ...201627548280
the role of hyalomma truncatum on the dynamics of rift valley fever: insights from a mathematical epidemic model.to date, our knowledge of rift valley fever (rvf) disease spread and maintenance is still limited, as flooding, humid weather and presence of biting insects such as mosquitoes, have not completely explained rvf outbreaks. we propose a model that includes livestock, mosquitoes and ticks compartments structured according to their questing and feeding behaviour in order to study the possible role of ticks on the dynamics of rvf. to quantify disease transmission at the initial stage of the epidemic, ...201727515276
safety and immunogenecity of a live attenuated rift valley fever vaccine (cl13t) in camels.rift valley fever is an emerging zoonotic viral disease, enzootic and endemic in africa and the arabian peninsula, which poses a significant threat to both human and animal health. the disease is most severe in ruminants causing abortions in pregnant animals, especially sheep animals and high mortality in young populations. high mortality rates and severe clinical manifestation have also been reported among camel populations in africa, to attend however none of the currently available live vacci ...201627457539
acute uncomplicated febrile illness in children aged 2-59 months in zanzibar - aetiologies, antibiotic treatment and outcome.despite the fact that a large proportion of children with fever in africa present at primary health care facilities, few studies have been designed to specifically study the causes of uncomplicated childhood febrile illness at this level of care, especially in areas like zanzibar that has recently undergone a dramatic change from high to low malaria transmission.201626821179
the two faces of rift valley fever virus virulence factor nss: the development of a vaccine and the elucidation of pathogenesis. 201627432532
arabidopsis thaliana plants expressing rift valley fever virus antigens: mice exhibit systemic immune responses as the result of oral administration of the transgenic plants.the zoonotic rift valley fever virus affects livestock and humans in africa and on the arabian peninsula. the economic impact of this pathogen due to livestock losses, as well as its relevance to public health, underscores the importance of developing effective and easily distributed vaccines. vaccines that can be delivered orally are of particular interest. here, we report the expression in transformed plants (arabidopsis thaliana) of rift valley fever virus antigens. the antigens used in this ...201627402440
rift valley fever virus: unanswered questions.this mosquito-borne pathogen of humans and animals respects no international or geographic boundaries. it is currently found in parts of africa and the arabian peninsula where periodic outbreaks of severe and fatal disease occur, and threatens to spread into other geographic regions. in recent years, modern molecular techniques have led to many breakthroughs deepening our understanding of the mechanisms of rvfv virulence, phylogenetics, and the creation of several next-generation vaccine candida ...201627400990
the arbo‑zoonet information system.the arbo‑zoonet information system has been developed as part of the 'international network for capacity building for the control of emerging viral vector borne zoonotic diseases (arbo‑zoonet)' project. the project aims to create common knowledge, sharing data, expertise, experiences, and scientific information on west nile disease (wnd), crimean‑congo haemorrhagic fever (cchf), and rift valley fever (rvf). these arthropod‑borne diseases of domestic and wild animals can affect humans, posing gre ...201627393878
seroprevalence of rift valley fever virus in sheep and goats in zambézia, mozambique.the rift valley fever virus (rvfv) is a vector-borne virus that causes disease in ruminants, but it can also infect humans. in humans, the infection can be asymptomatic but can also lead to illness, ranging from a mild disease with fever, headache and muscle pain to a severe disease with encephalitis and haemorrhagic fever. in rare cases, death can occur. in infected animals, influenza-like symptoms can occur, and abortion and mortality in young animals are indicative of rvfv infection. since th ...201627388698
multiplex detection of igg and igm to rift valley fever virus nucleoprotein, nonstructural proteins, and glycoprotein in ovine and bovine.a multiplex fluorescence microsphere immunoassay (fmia) was used to detect bovine and ovine igm and igg antibodies to several rift valley fever virus (rvfv) proteins, including the major surface glycoprotein, gn; the nonstructural proteins, nss and nsm; and the nucleoprotein, n. target antigens were assembled into a multiplex and tested in serum samples from infected wild-type rvfv or mp12, a modified live virus vaccine. as expected, the n protein was immunodominant and the best target for early ...201627380552
the role of signal transducer and activator of transcription 3 in rift valley fever virus infection.rift valley fever (rvf) is a zoonotic disease that can cause severe illness in humans and livestock, triggering spontaneous abortion in almost 100% of pregnant ruminants. in this study, we demonstrate that signal transducer and activator of transcription 3 (stat3) is phosphorylated on its conserved tyrosine residue (y705) following rvfv infection. this phosphorylation was dependent on a major virulence factor, the viral nonstructural protein nss. loss of stat3 had little effect on viral replicat ...201627318793
serological evidence of rift valley fever virus among acute febrile patients in southern mozambique during and after the 2013 heavy rainfall and flooding: implication for the management of febrile illness.rift valley fever virus (rvfv) remains heavily neglected in humans in mozambique, even though recent outbreaks were reported in neighboring countries in humans and several cases of rvfv in cattle were reported in several districts in mozambique.201627278404
attenuation of pathogenic rift valley fever virus strain through the chimeric s-segment encoding sandfly fever phlebovirus nss or a dominant-negative pkr.rift valley fever is a mosquito-borne zoonotic disease affecting ruminants and humans. rift valley fever virus (rvfv: family bunyaviridae, genus phlebovirus) causes abortions and fetal malformations in ruminants, and hemorrhagic fever, encephalitis, or retinitis in humans. the live-attenuated mp-12 vaccine is conditionally licensed for veterinary use in the us. however, this vaccine lacks a marker for the differentiation of vaccinated from infected animals (diva). nss gene is dispensable for rvf ...201627248570
geographically weighted discriminant analysis of environmental conditions associated with rift valley fever outbreaks in south africa.rift valley fever (rvf) is a zoonotic arboviral infection that has occurred across africa and parts of the middle east. geographically weighted discriminant analysis (gwda) is a spatially-adaptive extension of traditional discriminant analysis (da) which has rarely been applied to infectious disease epidemiology research. this study compares the classification performance of gwda and traditional da when used to distinguish between locations where livestock are at risk or are not at risk for acqu ...201627246274
mutational analysis of the rift valley fever virus glycoprotein precursor proteins for gn protein expression.the rift valley fever virus (rvfv) m-segment encodes the 78 kd, nsm, gn, and gc proteins. the 1st aug generates the 78 kd-gc precursor, the 2nd aug generates the nsm-gn-gc precursor, and the 3rd aug makes the nsm'-gn-gc precursor. to understand biological changes due to abolishment of the precursors, we quantitatively measured gn secretion using a reporter assay, in which a gaussia luciferase (gluc) protein is fused to the rvfv m-segment pre-gn region. using the reporter assay, the relative expr ...201627231931
n-glycans on the rift valley fever virus envelope glycoproteins gn and gc redundantly support viral infection via dc-sign.rift valley fever is a mosquito-transmitted, zoonotic disease that infects humans and ruminants. dendritic cell specific intercellular adhesion molecule 3 (icam-3) grabbing non-integrin (dc-sign) acts as a receptor for members of the phlebovirus genus. the rift valley fever virus (rvfv) glycoproteins (gn/gc) encode five putative n-glycan sequons (asparagine (n)-any amino acid (x)-serine (s)/threonine (t)) at positions: n438 (gn), and n794, n829, n1035, and n1077 (gc). the n-glycosylation profile ...201627223297
rift valley fever in kidney transplant recipient returning from mali with viral rna detected in semen up to four months from symptom onset, france, autumn 2015.a 29-year-old kidney transplant recipient returning from mali was diagnosed with rift valley fever (rvf) in france in autumn 2015. the patient was immunosuppressed due to his renal transplant. igm and igg specific to rvf virus (rvfv) were detected in cerebrospinal fluid and blood up to two months after symptom onset, whereas in urine, rvfv genomic rna was detected by rt-pcr up to three months, and in semen up to four months post symptom onset.201627172608
absence of rift valley fever virus in domestic and wild ruminants from spain. 201627162286
nss virulence factor of rift valley fever virus engages the f-box proteins fbxw11 and β-trcp1 to degrade the antiviral protein kinase pkr.rift valley fever virus (rvfv, family bunyaviridae, genus phlebovirus) is a relevant pathogen of both humans and livestock in africa. the nonstructural protein nss is a major virulence factor known to suppress the type i interferon (ifn) response by inhibiting host cell transcription and by proteasomal degradation of a major antiviral ifn effector, the translation-inhibiting protein kinase pkr. here, we identified components of the modular scf (skp1, cul1, f-box protein)-type e3 ubiquitin ligase ...201627122577
complete genome sequence of rift valley fever virus strain lunyo.using next-generation sequencing technologies, the first complete genome sequence of rift valley fever virus strain lunyo is reported here. originally reported as an attenuated antigenic variant strain from uganda, genomic sequence analysis shows that lunyo clusters together with other ugandan isolates.201627081121
application of droplet digital pcr to validate rift valley fever vaccines.droplet digital™ polymerase chain reaction (ddpcr™) is a promising technique that quantitates the absolute concentration of nucleic acids in a given sample. this technique utilizes water-in-oil emulsion technology, a system developed by bio-rad laboratories that partitions a single sample into thousands of nanoliter-sized droplets and counts nucleic acid molecules encapsulated in each individual particle as one pcr reaction. this chapter discusses the applications and methodologies of ddpcr for ...201627076132
generation of a single-cycle replicable rift valley fever vaccine.rift valley fever virus (rvfv) (genus phlebovirus, family bunyaviridae) is an arbovirus that causes severe disease in humans and livestock in sub-saharan african countries. the virus carries a tripartite, single-stranded, and negative-sense rna genome, designated as l, m, and s rnas. rvfv spread can be prevented by the effective vaccination of animals and humans. although the mp-12 strain of rvfv is a live attenuated vaccine candidate, mp-12 showed neuroinvasiveness and neurovirulence in young m ...201627076131
a dynamic, climate-driven model of rift valley fever.outbreaks of rift valley fever (rvf) in eastern africa have previously occurred following specific rainfall dynamics and flooding events that appear to support the emergence of large numbers of mosquito vectors. as such, transmission of the virus is considered to be sensitive to environmental conditions and therefore changes in climate can impact the spatiotemporal dynamics of epizootic vulnerability. epidemiological information describing the methods and parameters of rvf transmission and its d ...201627063737
development and characterization of rift valley fever virus-like particles.rift valley fever (rvf) is an acute, febrile zoonotic disease that is caused by the rvf virus (rvfv) and spread by arthropod vectors. rvf is currently prevalent in africa and the arabian peninsula, and causes substantial economic losses. furthermore, this disease poses a serious threat to animal and human health in regions worldwide, making it a serious public health concern. however, rvfv vaccines for human use are still unavailable, and hence there is an urgent need for novel efficient vaccine ...201627050999
rift valley fever vaccine virus clone 13 is able to cross the ovine placental barrier associated with foetal infections, malformations, and stillbirths.rift valley fever virus (rvfv) is a mosquito-borne pathogen that affects domesticated ruminants and occasionally humans. classical rvf vaccines are based on formalin-inactivated virus or the live-attenuated smithburn strain. the inactivated vaccine is highly safe but requires multiple administrations and yearly re-vaccinations. although the smithburn vaccine provides solid protection after a single vaccination, this vaccine is not safe for pregnant animals. an alternative live-attenuated vaccine ...201627031621
potency of a thermostabilised chimpanzee adenovirus rift valley fever vaccine in cattle.development of safe and efficacious vaccines whose potency is unaffected by long-term storage at ambient temperature would obviate major vaccine deployment hurdles and limit wastage associated with breaks in the vaccine cold chain. here, we evaluated the immunogenicity of a novel chimpanzee adenovirus vectored rift valley fever vaccine (chadox1-gngc) in cattle, following its thermostabilisation by slow desiccation on glass fiber membranes in the non-reducing sugars trehalose and sucrose. thermos ...201627020712
co-housing of rift valley fever virus infected lambs with immunocompetent or immunosuppressed lambs does not result in virus transmission.rift valley fever virus (rvfv) is transmitted among susceptible animals by mosquito vectors. although the virus can be isolated from nasal and oral swabs of infected animals and is known to be highly infectious when administered experimentally via oral or respiratory route, horizontal transmission of the virus is only sporadically reported in literature. we considered that immunosuppression resulting from stressful conditions in the field may increase the susceptibility to horizontally transmitt ...201627014211
differential use of the c-type lectins l-sign and dc-sign for phlebovirus endocytosis.bunyaviruses represent a growing threat to humans and livestock globally. the receptors, cellular factors and endocytic pathways used by these emerging pathogens to infect cells remain largely unidentified and poorly characterized. dc-sign is a c-type lectin highly expressed on dermal dendritic cells that has been found to act as an authentic entry receptor for many phleboviruses (bunyaviridae), including rift valley fever virus (rvfv), toscana virus (tosv) and uukuniemi virus (uukv). we found t ...201626990254
rift valley fever: an emerging mosquito-borne disease.rift valley fever (rvf), an emerging mosquito-borne zoonotic infectious viral disease caused by the rvf virus (rvfv) (bunyaviridae: phlebovirus), presents significant threats to global public health and agriculture in africa and the middle east. rvfv is listed as a select agent with significant potential for international spread and use in bioterrorism. rvfv has caused large, devastating periodic epizootics and epidemics in africa over the past ∼60 years, with severe economic and nutritional imp ...201626982443
potential application of silver nanoparticles to control the infectivity of rift valley fever virus in vitro and in vivo.in this work we have tested the potential antiviral activity of silver nanoparticles formulated as argovit™ against rift valley fever virus (rvfv). the antiviral activity of argovit was tested on vero cell cultures and in type-i interferon receptor deficient mice (ifnar (-/-) mice) by two different approaches: (i) different dilutions of argovit were added to previously infected cells or administrated to animals infected with a lethal dose of virus; (ii) virus was pre-incubated with different dil ...201626970026
chimpanzee adenovirus vaccine provides multispecies protection against rift valley fever.rift valley fever virus (rvfv) causes recurrent outbreaks of acute life-threatening human and livestock illness in africa and the arabian peninsula. no licensed vaccines are currently available for humans and those widely used in livestock have major safety concerns. a 'one health' vaccine development approach, in which the same vaccine is co-developed for multiple susceptible species, is an attractive strategy for rvfv. here, we utilized a replication-deficient chimpanzee adenovirus vaccine pla ...201626847478
the l, m, and s segments of rift valley fever virus mp-12 vaccine independently contribute to a temperature-sensitive phenotype.rift valley fever (rvf) is endemic to africa, and the mosquito-borne disease is characterized by "abortion storms" in ruminants and by hemorrhagic fever, encephalitis, and blindness in humans. rift valley fever virus (rvfv; family bunyaviridae, genus phlebovirus) has a tripartite negative-stranded rna genome (l, m, and s segments). a live-attenuated vaccine for rvf, the mp-12 vaccine, is conditionally licensed for veterinary use in the united states. mp-12 is fully attenuated by the combination ...201626819307
protein phosphatase-1 regulates rift valley fever virus replication.rift valley fever virus (rvfv), genus phlebovirus family bunyaviridae, is an arthropod-borne virus endemic throughout sub-saharan africa. recent outbreaks have resulted in cyclic epidemics with an increasing geographic footprint, devastating both livestock and human populations. despite being recognized as an emerging threat, relatively little is known about the virulence mechanisms and host interactions of rvfv. to date there are no fda approved therapeutics or vaccines for rvf and there is an ...201626801627
innate cellular immune responses in aedes caspius (diptera: culicidae) mosquitoes.mosquitoes transmit a variety of pathogens that have devastating consequences for global public and veterinary health. despite their capacity to serve as vectors, these insects have a robust capacity to respond to invading organisms with strong cellular and humoral immune responses. in egypt, aedes caspius (pallas, 1771) has been suspected to act as a bridge vector of rift valley fever virus between animals and humans. microscopic analysis of ae. caspius hemolymph revealed the presence of phagoc ...201626792848
surveillance of rift valley fever virus in mosquito vectors of the republic of korea.rift valley fever (rvf) is an acute mosquito-borne viral zoonotic disease that affects mainly domestic ruminants and humans. rvf virus (rvfv) was first identified in kenya in 1931 and was reported to be endemic in africa but has recently spread to the arabian peninsula. with increasing climate change and globalization of trade in animals and animal products, there is great concern that the disease will spread worldwide to regions such as europe, asia, and the americas. although rvfv has not been ...201626771529
high-throughput screening using a whole-cell virus replication reporter gene assay to identify inhibitory compounds against rift valley fever virus infection.rift valley fever virus (rvfv) is an emerging virus that causes serious illness in humans and livestock. there are no approved vaccines or treatments for humans. the purpose of the study was to identify inhibitory compounds of rvfv infection without any preconceived idea of the mechanism of action. a whole-cell-based high-throughput drug screening assay was developed to screen 28,437 small chemical compounds targeting rvfv infection. to accomplish both speed and robustness, a replication-compete ...201626762502
development of a sheep challenge model for rift valley fever.rift valley fever (rvf) is a zoonotic disease that causes severe epizootics in ruminants, characterized by mass abortion and high mortality rates in younger animals. the development of a reliable challenge model is an important prerequisite for evaluation of existing and novel vaccines. a study aimed at comparing the pathogenesis of rvf virus infection in us sheep using two genetically different wild type strains of the virus (sa01-1322 and kenya-128b-15) was performed. a group of sheep was inoc ...201626748334
safety and immunogenicity of a mutagenized, live attenuated rift valley fever vaccine, mp-12, in a phase 1 dose escalation and route comparison study in humans.rift valley fever (rvf) poses a risk as a potential agent in bioterrorism or agroterrorism. a live attenuated rvf vaccine (rvf mp-12) has been shown to be safe and protective in animals and showed promise in two initial clinical trials. in the present study, healthy adult human volunteers (n=56) received a single injection of (a) rvf mp-12, administered subcutaneously (sq) at a concentration of 10(4.7) plaque-forming units (pfu) (sq group); (b) rvf mp-12, administered intramuscularly (im) at 10( ...201626718688
rift valley fever mp-12 vaccine phase 2 clinical trial: safety, immunogenicity, and genetic characterization of virus isolates.an outbreak or deliberate release of rift valley fever (rvf) virus could have serious public health and socioeconomic consequences. a safe rvf vaccine capable of eliciting long-lasting immunity after a single injection is urgently needed. the live attenuated rvf mp-12 vaccine candidate has shown promise in phase 1 clinical trials; no evidence of reversion to virulence has been identified in numerous animal studies. the objective of this phase 2 clinical trial was to (a) further examine the safet ...201626706271
rift valley fever virus among wild ruminants, etosha national park, namibia, 2011.after a may 2011 outbreak of rift valley fever among livestock northeast of etosha national park, namibia, wild ruminants in the park were tested for the virus. antibodies were detected in springbok, wildebeest, and black-faced impala, and viral rna was detected in springbok. seroprevalence was high, and immune response was long lasting.201626692385
spatio-temporal variation in prevalence of rift valley fever: a post-epidemic serum survey in cattle and wildlife in kenya.rift valley fever (rvf) is a fatal arthropod-borne zoonotic disease of livestock and humans. since the identification of rvf in kenya in the 1930s, repeated epizootics and epidemics coinciding with el niño events have occurred in several locations in africa and saudi arabia, causing mass deaths of livestock and humans. rvf is of great interest worldwide because of its negative effect on international livestock trade and its potential to spread globally. the latter is due to the increasing incide ...201526679561
serological evidence of rift valley fever virus circulation in domestic cattle and african buffalo in northern botswana (2010-2011).rift valley fever (rvf) is endemic in many countries in sub-saharan africa and is responsible for severe outbreaks in livestock characterized by a sudden onset of abortions and high neonatal mortality. during the last decade, several outbreaks have occurred in southern africa, with a very limited number of cases reported in botswana. to date, published information on the occurrence of rvf in wild and domestic animals from botswana is very scarce and outdated, despite being critical to national a ...201526664990
rift valley fever.rift valley fever (rvf) is a mosquito-borne zoonotic viral disease affecting domestic and wild ruminants, camels and humans. the causative agent of rvf, the rvf virus (rvfv), has the capacity to cause large and severe outbreaks in animal and human populations and to cross significant natural geographic barriers. rift valley fever is usually inapparent in non-pregnant adult animals, but pregnant animals and newborns can be severely affected; outbreaks are characterised by a sudden onset of aborti ...201526601442
a study of rift valley fever virus in morogoro and arusha regions of tanzania - serology and farmers' perceptions.rift valley fever (rvf) is a zoonosis primarily affecting ruminants, resulting in epidemic abortions, fever, nasal and ocular discharges, haemorrhagic diarrhoea, and a high mortality rate among young animals. rift valley fever virus (rvfv) is an arthropod-borne rna virus occurring in epizootic periods associated with heavy rainfall. the last outbreak of rvf in tanzania was in 2006-2007, resulting in severe economic losses and impaired food security due to greater number of deaths of livestock. t ...201526584830
first external quality assessment of molecular and serological detection of rift valley fever in the western mediterranean region.rift valley fever (rvf) is a mosquito-borne viral zoonosis which affects humans and a wide range of domestic and wild ruminants. the large spread of rvf in africa and its potential to emerge beyond its geographic range requires the development of surveillance strategies to promptly detect the disease outbreaks in order to implement efficient control measures, which could prevent the widespread of the virus to humans. the animal health mediterranean network (remesa) linking some northern african ...201526566248
mapping a major gene for resistance to rift valley fever virus in laboratory rats.the rift valley fever virus (rvfv) presents an epidemic and epizootic threat in sub-saharan africa, egypt, and the arabian peninsula, and has furthermore recently gained attention as a potential weapon of bioterrorism due to its ability to infect both livestock and humans. inbred rat strains show similar characteristic responses to the disease as humans and livestock, making them a suitable model species. previous studies had indicated differences in susceptibility to rvfv hepatic disease among ...201526546799
training program for nursing staff regarding viral hemorrhagic fevers in a military hospital.viral hemorrhagic fevers (vhfs) refer to a group of illnesses caused by several distinct families of viruses. in general, the term "viral hemorrhagic fever" is used to describe a severe multisystem syndrome (multisystem in that multiple organ systems in the bpdy are affected). characteristically, the overall vascular system is damaged, and the body's ability to regulate itself is impaired. these symptoms are often accompanied by hemorrhage (bleeding); however, the bleeding is it rarely life-thre ...201526485844
seroepidemiological study of interepidemic rift valley fever virus infection among persons with intense ruminant exposure in madagascar and kenya.in this cross-sectional seroepidemiological study we sought to examine the evidence for circulation of rift valley fever virus (rvfv) among herders in madagascar and kenya. from july 2010 to june 2012, we enrolled 459 herders and 98 controls (without ruminant exposures) and studied their sera (immunoglobulin g [igg] and igm through enzyme-linked immunosorbent assay [elisa] and plaque reduction neutralization test [prnt] assays) for evidence of previous rvfv infection. overall, 59 (12.9%) of 459 ...201526458775
rift valley fever virus nss gene expression correlates with a defect in nuclear mrna export.we investigated the localization of host mrna during rift valley fever virus (rvfv) infection. fluorescence in situ hybridization revealed that infection with rvfv altered the localization of host mrna. mrna accumulated in the nuclei of rvfv-infected but not mock-infected cells. further, overexpression of the nss gene, but not the n, gn or nsm genes correlated with mrna nuclear accumulation. nuclear accumulation of host mrna was not observed in cells infected with a strain of rvfv lacking the ge ...201526410240
species diversity, abundance, and host preferences of mosquitoes (diptera: culicidae) in two different ecotypes of madagascar with recent rvfv transmission.mosquito diversity and abundance were examined in six madagascan villages in either arid (toliary ii district) or humid (mampikony district) ecotypes, each with a history of rift valley fever virus transmission. centers for disease control and prevention light traps without co2 (lt) placed near ruminant parks and animal-baited net trap (nt) baited with either zebu or sheep/goat were used to sample mosquitoes, on two occasions between march 2011 and october 2011. culex tritaeniorhynchus (giles) w ...201526336259
potential for psorophora columbiae and psorophora ciliata mosquitoes (diptera: culicidae) to transmit rift valley fever virus.rift valley fever virus (rvfv) continues to pose a threat to much of the world. unlike many arboviruses, numerous mosquito species have been associated with rvfv in nature, and many species have been demonstrated as competent vectors in the laboratory. in this study, we evaluated two field-collected psorophora species, psorophora columbiae (dyar and knab) and psorophora ciliata (f.) for their potential to transmit rvfv in north america. both species were susceptible to infection after feeding on ...201526336233
rift valley fever virus: a review of diagnosis and vaccination, and implications for emergence in europe.rift valley fever virus (rvfv) is a mosquito-borne virus, and is the causative agent of rift valley fever (rvf), a zoonotic disease characterised by an increased incidence of abortion or foetal malformation in ruminants. infection in humans can also lead to clinical manifestations that in severe cases cause encephalitis or haemorrhagic fever. the virus is endemic throughout much of the african continent. however, the emergence of rvfv in the middle east, northern egypt and the comoros archipelag ...201526296499
the effect of rift valley fever virus clone 13 vaccine on semen quality in rams.rift valley fever (rvf) is an arthropod-borne viral disease of importance in livestock and humans. epidemics occur periodically in domestic ruminants. people in contact with infected livestock may develop disease that varies from mild flu-like symptoms to fatal viraemia. livestock vaccination may assist in disease control. rift valley fever virus (rvfv) clone 13 is a relatively new vaccine against rvf, derived from an avirulent natural mutant strain of rvfv, and has been shown to confer protecti ...201526244683
safety and immunogenicity of onderstepoort biological products' rift valley fever clone 13 vaccine in sheep and goats under field conditions in senegal.this blinded field safety study was conducted in senegal to assess safety and immunogenicity of administration of the registered dose of rift valley fever virus (rvfv) clone 13 vaccine (onderstepoort biological products) to sheep and goats of west african breeds under natural conditions. a total of 267 small ruminants (220 sheep, 47 goats) were included; half received rvfv clone 13 vaccine at the recommended dose and half received the diluent (as placebo) only. the study was performed on three c ...201526244679
[infectious, immunogenic, and protective characteristics of the rift valley fever virus depending on the passage level and storage conditions].the report discusses the research into the impact of some factors, especially the passage in a suspension of continuous cells bhk-21/13 and storage at different temperatures, upon immunobiological characteristics of the rift valley fever (rvf) virus strain 1974-vniivvim. the limits for the passage levels and optimal storage conditions providing maximal infectious and immunogenic activity, as well as protection of the attenuated rvf strain 1974- vniivvim, were determined. it was found that the rv ...201526182657
mosquitoes and the environment in nile delta villages with previous rift valley fever activity.egypt is affected by serious human and animal mosquito-borne diseases such as rift valley fever (rvf). we investigated how potential rvf virus mosquito vector populations are affected by environmental conditions in the nile delta region of egypt by collecting mosquitoes and environmental data from 3 key governorates before and after 2012 seasonal flooding. we found that environmental effects varied among species, life stages, pre- and postflood groupings, and geographic populations of the same s ...201526181689
mp-12 virus containing the clone 13 deletion in the nss gene prevents lethal disease when administered after rift valley fever virus infection in hamsters.rift valley fever virus (rvfv; bunyaviridae, phlebovirus) causes a range of illnesses that include retinitis, fulminant hepatitis, neurologic disease, and hemorrhagic fever. in hospitalized individuals, case fatality rates can be as high as 10-20%. there are no vaccines or antivirals approved for human use to prevent or treat severe rvfv infections. we previously tested the efficacy of the mp-12 vaccine strain and related variants with nss truncations as a post-exposure prophylaxis in mice infec ...201526175722
a spatial analysis of rift valley fever virus seropositivity in domestic ruminants in tanzania.rift valley fever (rvf) is an acute arthropod-borne viral zoonotic disease primarily occurring in africa. since rvf-like disease was reported in tanzania in 1930, outbreaks of the disease have been reported mainly from the eastern ecosystem of the great rift valley. this cross-sectional study was carried out to describe the variation in rvf virus (rvfv) seropositivity in domestic ruminants between selected villages in the eastern and western rift valley ecosystems in tanzania, and identify poten ...201526162089
computational prediction and biochemical characterization of novel rna aptamers to rift valley fever virus nucleocapsid protein.rift valley fever virus (rvfv) is a potent human and livestock pathogen endemic to sub-saharan africa and the arabian peninsula that has potential to spread to other parts of the world. although there is no proven effective and safe treatment for rvfv infections, a potential therapeutic target is the virally encoded nucleocapsid protein (n). during the course of infection, n binds to viral rna, and perturbation of this interaction can inhibit viral replication. to gain insight into how n recogni ...201526141677
reassortment and distinct evolutionary dynamics of rift valley fever virus genomic segments.rift valley fever virus (rvfv) is a member of bunyaviridae family that causes a febrile disease affecting mainly ruminants and occasionally humans in africa, with symptoms that range from mid to severe. rvfv has a tri-segmented ssrna genome that permits reassortment and could generate more virulent strains. in this study, we reveal the importance of reassortment for rvfv evolution using viral gene genealogy inference and phylodynamics. we uncovered seven events of reassortment that originated rv ...201526100494
preliminary evaluation of a bunyavirus vector for cancer immunotherapy.replicon particles of rift valley fever virus, referred to as nonspreading rift valley fever virus (nsr), are intrinsically safe and highly immunogenic. here, we demonstrate that nsr-infected human dendritic cells can activate cd8(+) t cells in vitro and that prophylactic and therapeutic vaccinations of mice with nsr encoding a tumor-associated cd8 peptide can control the outgrowth of lymphoma cells in vivo. these results suggest that the nsr system holds promise for cancer immunotherapy.201526085169
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