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risk factors for severe rift valley fever infection in kenya, 2007.a large rift valley fever (rvf) outbreak occurred in kenya from december 2006 to march 2007. we conducted a study to define risk factors associated with infection and severe disease. a total of 861 individuals from 424 households were enrolled. two hundred and two participants (23%) had serologic evidence of acute rvf infection. of these, 52 (26%) had severe rvf disease characterized by hemorrhagic manifestations or death. independent risk factors for acute rvf infection were consuming or handli ...201020682901
epidemiologic and clinical aspects of a rift valley fever outbreak in humans in tanzania, 2007.in january 2007, an outbreak of rift valley fever (rvf) was detected among humans in northern tanzania districts. by the end of the outbreak in june, 2007, 511 suspect rvf cases had been recorded from 10 of the 21 regions of tanzania, with laboratory confirmation of 186 cases and another 123 probable cases. all confirmed rvf cases were located in the north-central and southern regions of the country, with an eventual fatality rate of 28.2% (n = 144). all suspected cases had fever; 89% had enceph ...201020682902
rift valley fever virus epidemic in kenya, 2006/2007: the entomologic investigations.in december 2006, rift valley fever (rvf) was diagnosed in humans in garissa hospital, kenya and an outbreak reported affecting 11 districts. entomologic surveillance was performed in four districts to determine the epidemic/epizootic vectors of rvf virus (rvfv). approximately 297,000 mosquitoes were collected, 164,626 identified to species, 72,058 sorted into 3,003 pools and tested for rvfv by reverse transcription-polymerase chain reaction. seventy-seven pools representing 10 species tested po ...201020682903
pathologic studies on suspect animal and human cases of rift valley fever from an outbreak in eastern africa, 2006-2007.rift valley fever (rvf) is an important viral zoonotic disease in africa with periodic outbreaks associated with severe disease, death, and economic hardship. during the 2006-2007 outbreaks in eastern africa, postmortem and necropsy tissue samples from 14 animals and 20 humans clinically suspected of rvf were studied with histopathologic evaluation and immunohistochemical (ihc) assays. six animal and 11 human samples had ihc evidence of rift valley fever virus (rvfv) antigens. we found that exte ...201020682904
prediction, assessment of the rift valley fever activity in east and southern africa 2006-2008 and possible vector control strategies.historical outbreaks of rift valley fever (rvf) since the early 1950s have been associated with cyclical patterns of the el niño/southern oscillation (enso) phenomenon, which results in elevated and widespread rainfall over the rvf endemic areas of africa. using satellite measurements of global and regional elevated sea surface temperatures, elevated rainfall, and satellite derived-normalized difference vegetation index data, we predicted with lead times of 2-4 months areas where outbreaks of rv ...201020682905
an assessment of the regional and national socio-economic impacts of the 2007 rift valley fever outbreak in kenya.although rift valley fever (rvf) has significant impacts on human health and livestock production, it can also induce significant (and often overlooked) economic losses among various stakeholders in the marketing chain. this work assesses and quantifies the multi-dimensional socio-economic impacts of the 2007 rvf outbreak in kenya based on a rapid assessment of livestock value chains in the northeast part of the country and a national macroeconomic analysis. although study results show negative ...201020682906
infectious lassa virus, but not filoviruses, is restricted by bst-2/tetherin.bone marrow stromal antigen 2 (bst-2/tetherin) is a cellular membrane protein that inhibits the release of hiv-1. we show for the first time, using infectious viruses, that bst-2 also inhibits egress of arenaviruses but has no effect on filovirus replication and spread. specifically, infectious lassa virus (lasv) release significantly decreased or increased in human cells in which bst-2 was either stably expressed or knocked down, respectively. in contrast, replication and spread of infectious z ...201020686043
the american society for virology--29th annual meeting.the american society for virology 29th annual meeting, held in bozeman, mt, usa, included topics covering new vaccine technologies, delivery methods and treatments in the field of virology. this conference report highlights selected presentations on human norovirus (hunov), sars coronavirus and rift valley fever virus vaccine technologies; programmed cell death-1 (pd1) blockade and hyperacute alpha-gal platform technology methods; aerosol vaccination delivery; novel technologies to produce influ ...201020799142
rift valley fever: scientific pathways to public health prevention and response. proceedings of a workshop. may 2008. nairobi. 201020824895
the pathogenesis of rift valley fever virus in the mouse model.detailed studies describing the pathogenesis of rift valley fever (rvf) virus (rvfv) in the mouse model are lacking. a fully characterized small animal model of rvf is needed to evaluate potential vaccines and therapeutics. in this study, we characterized the pathogenesis of rvfv throughout the disease course in mice. infection produced high-titer viremia and demonstrated rvfv tropism for a variety of tissue and individual cell types. overwhelming infection of hepatocytes, accompanied by apoptos ...201020850165
replication of clone 13, a naturally attenuated avirulent isolate of rift valley fever virus, in aedes and culex mosquitoes.rift valley fever virus continues to cause large outbreaks of acute and febrile illness among humans and domestic animals in africa. the high pathogenicity of the virus is mainly due to the non-structural protein derived from the s segment nss, which was shown to inhibit the type i interferon expression at the transcriptional level and to suppress host cell rna synthesis. clone 13, a naturally attenuated clone containing a deletion of 70% in nss, is a promising vaccine candidate as it has no pat ...201020854021
experimental infection of young adult european breed sheep with rift valley fever virus field isolates.the increasing interest in rift valley fever virus (rvfv) and its potential impact on naive animal populations deserve revisiting experimental reproduction of rvfv infection, particularly in those animal breeds for which no data about their susceptibility to rvfv infection have ever been recorded. in this study we show the susceptibility of 9-10 weeks old european sheep (ripollesa breed) to rvfv infection, showing a mild, subacute form of disease. four different viral isolates efficiently replic ...201020854022
comparison of enzyme-linked immunosorbent assay-based techniques for the detection of antibody to rift valley fever virus in thermochemically inactivated sheep sera.different enzyme-linked immunosorbent assay (elisa)-based techniques for the detection of antibodies to rift valley fever virus (rvfv) have been developed in recent years, but their diagnostic sensitivity was not directly compared. in addition, their use might still be restricted to high biocontainment facilities when sera to be tested are collected from viremic individuals. in this study, we report on direct comparison of various elisa forms for the detection of anti-rvfv antibody in preinactiv ...201020854023
virus-like particles expressing the nucleocapsid gene as an efficient vaccine against rift valley fever virus.rift valley fever virus (rvfv), a member of the family bunyaviridae, regularly accounts for large and severe outbreaks among humans and livestock in africa and arabia. therefore, safe and efficient vaccines are highly needed. here, we report the production of recombinant virus-like particles (vlps) that, in addition to their similarity to rvfv particles, are able to express the viral nucleocapsid (n) gene. a single inoculation of 1 × 10(6) of these n-vlps was sufficient to protect 100% of mice f ...201020854024
identification of potential vectors of and detection of antibodies against rift valley fever virus in livestock during interepizootic periods.to evaluate the prevalence of rift valley fever virus (rvfv) antibodies in livestock and presence of competent mosquito vectors of rvfv during an interepizootic period (iep) in kenya.201020433377
rift valley fever virus immunity provided by a paramyxovirus vaccine vector.rift valley fever virus (rvfv) causes recurrent large outbreaks among humans and livestock. although the virus is currently confined to the african continent and the arabian peninsula, there is a growing concern for rvfv incursions into countries with immunologically naïve populations. the rvfv structural glycoproteins gn and gc are preferred targets in the development of subunit vaccines that can be used to control future outbreaks. we here report the production of gn and gc by a recombinant va ...201020434545
rift valley fever among febrile patients at new halfa hospital, eastern sudan.since the first isolation of the rift valley fever virus (rvfv) in 1930s, there have been several epizootics outbreaks in the tropic mainly in africa including sudan. recognition of cases and diagnosis of rvf are critical for management and control of the disease.201020465791
evaluation of the efficacy and safety of the rift valley fever clone 13 vaccine in sheep.the efficacy and safety of the naturally attenuated rift valley fever (rvf) clone 13 vaccine were evaluated in ovines in three different experiments involving 38 ewes at different stages of pregnancy, their offsprings and four rams. in experiment 1, 4 rams and a total of 13 pregnant ewes were vaccinated and monitored during vaccination and after a challenge with a virulent rvf virus. the ewes were vaccinated at either 50 or 100 days of pregnancy and some were challenged after lambing. in experim ...201020470792
distribution and seasonal activity of mosquitoes in al madinah al munwwrah, saudi arabia.in this study, 2654 adults and mosquito larvae, which belong to 18 species and 4 genera, were collected: aedes (2 spp.), anopheles (7 spp.), culex (8 spp.) and culiseta (1 sp.). they were aedes caspius, ae. aegypti, anopheles. azaniae, an. d'thali, an. multicolor, an. rhodesiensis, an. stephensi, an. sub-pictus, an. turkhudi, culex laticinctus, cx. perexiguus, cx. pipiens, cx. quin-quefasciatus, cx. simpsoni, cx. theileri, cx. tritaeniorhynchus, cx. univittatus and culiseta longiareolata. a tota ...201020503600
rift valley fever during rainy seasons, madagascar, 2008 and 2009.during 2 successive rainy seasons, january 2008 through may 2008 and november 2008 through march 2009, rift valley fever virus (rvfv) caused outbreaks in madagascar. human and animal infections were confirmed on the northern and southern coasts and in the central highlands. analysis of partial sequences from rvfv strains showed that all were similar to the strains circulating in kenya during 2006-2007. a national cross-sectional serologic survey among slaughterhouse workers at high risk showed t ...201020507747
molecular biology of rift valley fever virus.rift valley fever virus (rvfv) causes large outbreaks of acute febrile and often fatal illness among humans and domesticated animals in sub-saharan africa and the arabian peninsula. rvfv is a member of the family bunyaviridae, genus phlebovirus. like all members of this large virus family, it contains a three-segmented genome of negative/ambisense strand rna, packaged into viral nucleocapsid protein, and enveloped by a lipid bilayer containing two viral glycoproteins. during the past years, ther ...201020517489
structure of the rift valley fever virus nucleocapsid protein reveals another architecture for rna encapsidation.rift valley fever virus (rvfv) is a negative-sense rna virus (genus phlebovirus, family bunyaviridae) that infects livestock and humans and is endemic to sub-saharan africa. like all negative-sense viruses, the segmented rna genome of rvfv is encapsidated by a nucleocapsid protein (n). the 1.93-a crystal structure of rvfv n and electron micrographs of ribonucleoprotein (rnp) reveal an encapsidated genome of substantially different organization than in other negative-sense rna virus families. the ...201020547879
characterization of a sandfly fever sicilian virus isolated during a sandfly fever epidemic in turkey.phleboviruses cause sandfly fever but isolates are rare.201020579934
vaccination with dna plasmids expressing gn coupled to c3d or alphavirus replicons expressing gn protects mice against rift valley fever virus.rift valley fever (rvf) is an arthropod-borne viral zoonosis. rift valley fever virus (rvfv) is an important biological threat with the potential to spread to new susceptible areas. in addition, it is a potential biowarfare agent.201020582312
advances in rift valley fever research: insights for disease prevention.the purpose was to review recent research on rift valley fever virus (rvfv) infection, encompassing four main areas: epidemiology and outbreak prediction, viral pathogenesis, human diagnostics and therapeutics, and vaccine and therapeutic candidates.201020613512
arboviral encephalitides: transmission, emergence, and pathogenesis.arthropod-borne viruses (arboviruses) are of paramount concern as a group of pathogens at the forefront of emerging and re-emerging diseases. although some arboviral infections are asymptomatic or present with a mild influenza-like illness, many are important human and veterinary pathogens causing serious illness ranging from rash and arthritis to encephalitis and hemorrhagic fever. here, we discuss arboviruses from diverse families (flaviviruses, alphaviruses, and the bunyaviridae) that are cau ...201020652430
novel suspension cell-based vaccine production systems for rift valley fever virus-like particles.rift valley fever virus (rvfv) is an arthropod-borne pathogen that often results in severe morbidity and mortality in both humans and livestock. as its geographic range continues to expand, it presents a real threat to naïve populations around the world by accidental introduction (e.g., the result of increased travel) or intentional release (e.g., a bioterror event). while there is a clear need for a safe and efficacious vaccine against this emerging and re-emerging pathogen, no fda-approved vac ...201020655330
rift valley fever virus seroprevalence in human rural populations of gabon.rift valley fever (rvf) is a mosquito-borne viral zoonosis caused by a phlebovirus and transmitted by aedes mosquitoes. humans can also be infected through direct contact with blood (aerosols) or tissues (placenta, stillborn) of infected animals. although severe clinical cases can be observed, infection with rvf virus (rvfv) in humans is, in most cases, asymptomatic or causes a febrile illness without serious symptoms. in small ruminants rvfv mainly causes abortion and neonatal death. the distri ...201020668541
intramuscular inoculation of calves with an experimental newcastle disease virus-based vector vaccine elicits neutralizing antibodies against rift valley fever virus.in the past decade, the use of newcastle disease virus (ndv) as a vaccine vector for the prevention of economically important livestock diseases as well as for human diseases has been extensively explored. in this study, we have constructed a recombinant ndv vaccine virus, named ndfl-gn, that produces the rift valley fever virus (rvfv) gn glycoprotein. calves were immunized via either the intranasal route or the intramuscular route. delivery via the intranasal route elicited no detectable antibo ...201020079874
a broad-spectrum antiviral targeting entry of enveloped viruses.we describe an antiviral small molecule, lj001, effective against numerous enveloped viruses including influenza a, filoviruses, poxviruses, arenaviruses, bunyaviruses, paramyxoviruses, flaviviruses, and hiv-1. in sharp contrast, the compound had no effect on the infection of nonenveloped viruses. in vitro and in vivo assays showed no overt toxicity. lj001 specifically intercalated into viral membranes, irreversibly inactivated virions while leaving functionally intact envelope proteins, and inh ...201020133606
species-independent bioassay for sensitive quantification of antiviral type i interferons.studies of the host response to infection often require quantitative measurement of the antiviral type i interferons (ifn-alpha/beta) in biological samples. the amount of ifn is either determined via its ability to suppress a sensitive indicator virus, by an ifn-responding reporter cell line, or by elisa. these assays however are either time-consuming and lack convenient readouts, or they are rather insensitive and restricted to ifn from a particular host species.201020187932
protection against lethal rift valley fever virus (rvfv) infection in transgenic ifnar(-/-) mice induced by different dna vaccination regimens.in this work, plasmid constructs encoding two different m segment orfs, as well as the nucleoprotein n, have been used in different vaccination regimes to test protection against a rvfv-mp12 virus challenge in a transgenic mouse model with impaired interferon type i response (ifnar(-/-)). we obtained dose dependent protection in animals immunized with a construct encoding both mature glycoproteins (pcmv-m4), whereas only partial protection in animals vaccinated with either n construct (pcmv-n) o ...201020188678
severe rift valley fever may present with a characteristic clinical syndrome.rift valley fever (rvf) virus is an emerging pathogen that is transmitted in many regions of sub-saharan africa, parts of egypt, and the arabian peninsula. outbreaks of rvf, like other diseases caused by hemorrhagic fever viruses, typically present in locations with very limited health resources, where initial diagnosis must be based only on history and physical examination. although general signs and symptoms of human rvf have been documented, a specific clinical syndrome has not been described ...201020207858
role of culex and anopheles mosquito species as potential vectors of rift valley fever virus in sudan outbreak, 2007.rift valley fever (rvf) is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the phlebovirus genus, one of the five genera in the family bunyaviridae. rvf virus (rvfv) is transmitted between animals and human by mosquitoes, particularly those belonging to the culex, anopheles and aedes genera.201020222979
present and future arboviral threats.arthropod-borne viruses (arboviruses) are important causes of human disease nearly worldwide. all arboviruses circulate among wild animals, and many cause disease after spillover transmission to humans and agriculturally important domestic animals that are incidental or dead-end hosts. viruses such as dengue (denv) and chikungunya (chikv) that have lost the requirement for enzootic amplification now produce extensive epidemics in tropical urban centers. many arboviruses recently have increased i ...201019857523
novel infectious agents causing uveitis.in any patient with uveitis, an infectious cause should be ruled out first. the differential diagnosis includes multiple well-known diseases including herpes, syphilis, toxoplasmosis, tuberculosis, bartonellosis, lyme disease, and others. however, clinician should be aware of emerging infectious agents as potential causes of systemic illness and also intraocular inflammation. air travel, immigration, and globalization of business have overturned traditional pattern of geographic distribution of ...201019711015
nonstructural nss protein of rift valley fever virus interacts with pericentromeric dna sequences of the host cell, inducing chromosome cohesion and segregation defects.rift valley fever virus (rvfv) is an emerging, highly pathogenic virus; rvfv infection can lead to encephalitis, retinitis, or fatal hepatitis associated with hemorrhagic fever in humans, as well as death, abortions, and fetal deformities in animals. rvfv nonstructural nss protein, a major factor of the virulence, forms filamentous structures in the nuclei of infected cells. in order to further understand rvfv pathology, we investigated, by chromatin immunoprecipitation, immunofluorescence, fluo ...201019889787
a replication-incompetent rift valley fever vaccine: chimeric virus-like particles protect mice and rats against lethal challenge.virus-like particles (vlps) present viral antigens in a native conformation and are effectively recognized by the immune system and therefore are considered as suitable and safe vaccine candidates against many viral diseases. here we demonstrate that chimeric vlps containing rift valley fever virus (rvfv) glycoproteins g(n) and g(c), nucleoprotein n and the gag protein of moloney murine leukemia virus represent an effective vaccine candidate against rift valley fever, a deadly disease in humans ...201019932911
assessing the impact of climate change on vector-borne viruses in the eu through the elicitation of expert opinion.expert opinion was elicited to undertake a qualitative risk assessment to estimate the current and future risks to the european union (eu) from five vector-borne viruses listed by the world organization for animal health. it was predicted that climate change will increase the risk of incursions of african horse sickness virus (ahsv), crimean-congo haemorrhagic fever virus (cchfv) and rift valley fever virus (rvfv) into the eu from other parts of the world, with african swine fever virus (asfv) a ...201019580695
manifestations of severe rift valley fever in sudan. 201019570703
rift valley fever virus subunit vaccines confer complete protection against a lethal virus challenge.rift valley fever virus (rvfv) is an emerging mosquito-borne virus causing significant morbidity and mortality in livestock and humans. rift valley fever is endemic in africa, but also outside this continent outbreaks have been reported. here we report the evaluation of two vaccine candidates based on the viral gn and gc envelope glycoproteins, both produced in a drosophila insect cell expression system. virus-like particles (vlps) were generated by merely expressing the gn and gc glycoproteins. ...201020056185
interview with dr. anthony r. fooks. interview by vicki glaser. 201020854027
interventions against west nile virus, rift valley fever virus, and crimean-congo hemorrhagic fever virus: where are we?arbo-zoonet is an international network financed by the european commission's seventh framework program. the major goal of this initiative is capacity building for the control of emerging viral vector-borne zoonotic diseases, with a clear focus on west nile virus, rift valley fever virus, and crimean-congo hemorrhagic fever virus. to evaluate the status quo of control measures against these viruses, an arbo-zoonet meeting was held in istanbul, turkey, from 19 to 20 november 2009. the symposium c ...201020854026
verification of poultry carcass composting research through application during actual avian influenza outbreaks.an avian influenza outbreak in 2002 affected 197 poultry farms in virginia and cost an estimated $130 million in losses and cleanup. in 2004-2005, researchers initiated a project to investigate the feasibility and practicality of in-house composting of turkey mortalities (heavy hens and toms) as a method of disposal and disease containment. occurrences of low pathogenic avian influenza (lpai) in west virginia and virginia in 2007 provided an opportunity for first responders to verify composting ...201020375437
rapid accumulation of virulent rift valley fever virus in mice from an attenuated virus carrying a single nucleotide substitution in the m rna.rift valley fever virus (rvfv), a member of the genus phlebovirus within the family bunyaviridae, is a negative-stranded rna virus with a tripartite genome. rvfv is transmitted by mosquitoes and causes fever and severe hemorrhagic illness among humans, while in livestock it causes fever and high abortion rates.201020376320
emergence of zoonotic arboviruses by animal trade and migration.abstract: arboviruses are transmitted in nature exclusively or to a major extend by arthropods. they belong to the most important viruses invading new areas in the world and their occurrence is strongly influenced by climatic changes due to the life cycle of the transmitting vectors. several arboviruses have emerged in new regions of the world during the last years, like west nile virus (wnv) in the americas, usutu virus (usuv) in central europe, or rift valley fever virus (rvfv) in the arabian ...201020377873
development and characterization of monoclonal antibodies against rift valley fever virus nucleocapsid protein generated by dna immunization.this paper describes the generation of monoclonal antibodies directed to immunogenic nucleoprotein n epitopes of rift valley fever virus (rvfv), and their application in diagnostics, both for antibody detection in competitive elisa and for antigen capture in a sandwich elisa. monoclonal antibodies (mabs) were generated after dna immunization of balb/c mice and characterized by western blot, elisa and cell immunostaining assays. at least three different immunorelevant epitopes were defined by mab ...201020400862
towards a safe, effective vaccine for rift valley fever virus.rift valley fever virus (rvfv) is an important animal and human threat and leads to longstanding morbidity and mortality in susceptible hosts. since no therapies currently exist to treat rift valley fever, it remains a public and animal health priority to develop safe, effective rvfv vaccines (whether for animals, humans, or both) that provide long-term protective immunity. in the evaluated article, bhardwaj and colleagues describe the creation and testing of two successful vaccine strategies ag ...201021423850
protection of sheep against rift valley fever virus and sheep poxvirus with a recombinant capripoxvirus vaccine.rift valley fever (rvf) is an epizootic viral disease of sheep that can be transmitted from sheep to humans, particularly by contact with aborted fetuses. a capripoxvirus (cpv) recombinant virus (rks1/rvfv) was developed, which expressed the rift valley fever virus (rvfv) gn and gc glycoproteins. these expressed glycoproteins had the correct size and reacted with monoclonal antibodies (mab) to native glycoproteins. mice vaccinated with rks1/rvfv were protected against rvfv challenge. sheep vacci ...201020876822
a new mouse model reveals a critical role for host innate immunity in resistance to rift valley fever.rift valley fever (rvf) is an arthropod-borne viral disease repeatedly reported in many african countries and, more recently, in saudi arabia and yemen. rvf virus (rvfv) primarily infects domesticated ruminants, resulting in miscarriage in pregnant females and death for newborns and young animals. it also has the ability to infect humans, causing a feverish syndrome, meningoencephalitis, or hemorrhagic fever. the various outcomes of rvfv infection in animals and humans argue for the existence of ...201020937849
potential for north american mosquitoes (diptera: culicidae) to transmit rift valley fever virus.to determine which arthropods should be targeted for control should rift valley fever virus (rvfv) be detected in north america, we evaluated culex erraticus (dyar and knab), culex erythrothorax dyar, culex nigripalpus theobald, culex pipiens l., culex quinquefasciatus say, culex tarsalis coquillett, aedes dorsalis (wiedemann), aedes vexans (meigen), anopheles quadrimaculatus say, and culicoides sonorensis wirth and jones from the western, midwestern, and southern united states for their ability ...201020939385
risk assessment of the introduction of rift valley fever from the horn of africa to yemen via legal trade of small ruminants.rift valley fever (rvf) is a mosquito-borne viral zoonosis of increasing global importance. occurring since 1930 across africa, it was detected for the first time in saudi arabia and yemen in september 2000, leading to human deaths and major losses in livestock populations. assuming the virus has not survived in yemen or has been circulating at a low level, authors qualitatively assessed the likelihood of "re-introduction" of rvf into yemen through the legal importation of small ruminants from t ...201020967567
pathogenic landscapes: interactions between land, people, disease vectors, and their animal hosts.landscape attributes influence spatial variations in disease risk or incidence. we present a review of the key findings from eight case studies that we conducted in europe and west africa on the impact of land changes on emerging or re-emerging vector-borne diseases and/or zoonoses. the case studies concern west nile virus transmission in senegal, tick-borne encephalitis incidence in latvia, sandfly abundance in the french pyrenees, rift valley fever in the ferlo (senegal), west nile fever and t ...201020979609
detection, isolation, and genetic characterization of rift valley fever virus from anopheles (anopheles) coustani, anopheles (anopheles) squamosus, and culex (culex) antennatus of the haute matsiatra region, madagascar.abstract following veterinary alerts of rift valley fever (rvf) in the districts of fianarantsoa i and ii in november 2008 and in the district of ambalavao in april 2009, entomological and virological investigations were carried out to identify the mosquito species that could act as rvf virus (rvfv) vectors in the region. a total of 12,785 adult mosquitoes belonging to 5 genera and 21 species were collected. after identification, mosquitoes were pooled by species, sex, and female status (fed or ...201021028960
reverse-phase phosphoproteome analysis of signaling pathways induced by rift valley fever virus in human small airway epithelial cells.rift valley fever virus (rvfv) infection is an emerging zoonotic disease endemic in many countries of sub-saharan africa and in egypt. in this study we show that human small airway epithelial cells are highly susceptible to rvfv virulent strain zh-501 and the attenuated strain mp-12. we used the reverse-phase protein arrays technology to identify phosphoprotein signaling pathways modulated during infection of cultured airway epithelium. zh-501 infection induced activation of map kinases (p38, jn ...201021072193
planning for rift valley fever virus: use of geographical information systems to estimate the human health threat of white-tailed deer (odocoileus virginianus)-related transmission.rift valley fever (rvf) virus is a mosquito-borne phlebovirus of the bunyaviridae family that causes frequent outbreaks of severe animal and human disease in sub-saharan africa, egypt and the arabian peninsula. based on its many known competent vectors, its potential for transmission via aerosolization, and its progressive spread from east africa to neighbouring regions, rvf is considered a high-priority, emerging health threat for humans, livestock and wildlife in all parts of the world. introd ...201021080319
rift valley fever virus infection of human cells and insect hosts is promoted by protein kinase c epsilon.as an arthropod-borne human pathogen, rift valley fever virus (rvfv) cycles between an insect vector and mammalian hosts. little is known about the cellular requirements for infection in either host. here we developed a tissue culture model for rvfv infection of human and insect cells that is amenable to high-throughput screening. using this approach we screened a library of 1280 small molecules with pharmacologically defined activities and identified 59 drugs that inhibited rvfv infection with ...201021124804
[assessment of the risk of introduction to tunisia of the rift valley fever virus by the mosquito culex pipiens.]the mosquito culex pipiens has been involved as vector of the west nile virus in tunisia. its bio-ecological characteristics in combination with some environmental factors have favoured the emergence of this virus in a west-nile free zone. this leads to question about the potential risk of introducing another arbovirus, the rift valley fever (rvf) virus, in tunisia from neighbouring countries where rvf circulates. in this study, we have evaluated the vector competence of different populations of ...201021184293
mechanism of tripartite rna genome packaging in rift valley fever virus.the bunyaviridae family includes pathogens of medical and veterinary importance. rift valley fever virus (rvfv), a member in the phlebovirus genus of the family bunyaviridae, is endemic to sub-saharan africa and causes a mosquito-borne disease in ruminants and humans. viruses in the family bunyaviridae carry a tripartite, single-stranded, negative-sense rna genome composed of l, m, and s rnas. little is known about how the three genomic rna segments are copackaged to generate infectious bunyavir ...201021187405
rift valley fever virus(bunyaviridae: phlebovirus): an update on pathogenesis, molecular epidemiology, vectors, diagnostics and prevention.rift valley fever(rvf) virus is an arbovirus in the bunyaviridae family that, from phylogenetic analysis, appears to have first emerged in the mid-19th century and was only identified at the beginning of the 1930's in the rift valley region of kenya. despite being an arbovirus with a relatively simple but temporally and geographically stable genome, this zoonotic virus has already demonstrated a real capacity for emerging in new territories, as exemplified by the outbreaks in egypt (1977), weste ...201021188836
sequential rift valley fever outbreaks in eastern africa caused by multiple lineages of the virus.during the rift valley fever (rvf) epidemic of 2006-2007 in eastern africa, spatial mapping of the outbreaks across kenya, somalia, and tanzania was performed and the rvf viruses were isolated and genetically characterized.201021282193
potential for stable flies and house flies (diptera: muscidae) to transmit rift valley fever virus.rift valley fever (rvf), a disease of ruminants and humans, has been responsible for large outbreaks in africa that have resulted in hundreds of thousands of human infections and major economic disruption due to loss of livestock and to trade restrictions. as indicated by the rapid spread of west nile viral activity across north america since its discovery in 1999 and the rapid and widespread movement of chikungunya virus from africa throughout the indian ocean islands to asia and europe, an int ...201021290943
a novel system for identification of inhibitors of rift valley fever virus replication.rift valley fever virus (rvfv) is a human and livestock pathogen endemic to sub-saharan africa. we have developed a t7-dependent system for the efficient production of rvfv-like particles (rvf-vlps) based on the virulent zh-501 strain of rvfv. the rvf-vlps are capable of performing a single round of infection, allowing for the study of viral replication, assembly, and infectivity. we demonstrate that these rvf-vlps are antigenically indistinguishable from authentic rvfv and respond similarly to ...201021994655
decision-support tool for prevention and control of rift valley fever epizootics in the greater horn of africa.in east africa, rift valley fever (rvf) usually occurs as explosive epizootics with prolonged inter-epidemic periods on the order of 8 to 10 years. the episodic nature of the disease and the rapid evolution of outbreaks create special challenges for its mitigation and control. following the events of the 2006 and 2007 rvf outbreak in east africa, decision-makers assembled their collective experiences in the form of a risk-based decision support tool to help guide responses in future emergencies. ...201020682910
restriction of rift valley fever virus virulence in mosquito cells.arboviruses are maintained in a natural cycle that requires blood-sucking arthropod and vertebrate hosts. arboviruses are believed to persistently infect their arthropod host without overt pathology and cause acute infection with viremia in their vertebrate host. we have focused on elucidating how a specific arbovirus, rift valley fever (rvf) virus, causes cytopathic effect in cells derived from vertebrates and non-cytopathic infection in cells derived from arthropods. we demonstrate that the ve ...201021994651
the historical and recent impact of rift valley fever in africa. 201020682909
rift valley fever virus: an unrecognized emerging threat?rift valley fever virus (rvfv) is an arthropod-borne pathogen that often results in severe morbidity and mortality in both humans and livestock. as its geographic range continues to spread, it presents a real threat to naïve populations around the world by accidental introduction (e.g., the result of increased world travel) or a bioterror event. the lack of prophylactic and therapeutic measures, the potential for human-to-human transmission, and the significant threat to livestock associated wit ...201020421731
epidemiological assessment of the rift valley fever outbreak in kenya and tanzania in 2006 and 2007.to capture lessons from the 2007 rift valley fever (rvf) outbreak, epidemiological studies were carried out in kenya and tanzania. somali pastoralists proved to be adept at recognizing symptoms of rvf and risk factors such as heavy rainfall and mosquito swarms. sandik, which means "bloody nose," was used by somalis to denote disease consistent with rvf. somalis reported that sandik was previously seen in 1997/98, the period of the last rvf epidemic. pastoralists communicated valuable epidemiolog ...201020682908
rift valley fever outbreak in livestock in kenya, 2006-2007.we analyzed the extent of livestock involvement in the latest rift valley fever (rvf) outbreak in kenya that started in december 2006 and continued until june 2007. when compared with previous rvf outbreaks in the country, the 2006-07 outbreak was the most extensive in cattle, sheep, goats, and camels affecting thousands of animals in 29 of 69 administrative districts across six of the eight provinces. this contrasted with the distribution of approximately 700 human rvf cases in the country, whe ...201020682907
recombinant rift valley fever vaccines induce protective levels of antibody in baboons and resistance to lethal challenge in mice.rift valley fever (rvf) is a zoonotic disease endemic in africa and the arabian peninsula caused by the highly infectious rift valley fever virus (rvfv) that can be lethal to humans and animals and results in major losses in the livestock industry. rvf is exotic to the united states; however, mosquito species native to this region can serve as biological vectors for the virus. thus, accidental or malicious introduction of this virus could result in rvfv becoming endemic in north america. such an ...201121873194
Characterization of wild-type and alternate transcription termination signals in the Rift Valley fever virus genome.Rift Valley fever (RVF) is a mosquito-borne zoonotic disease caused by a phlebovirus of the family Bunyaviridae, which affects humans and ruminants in Africa and the Middle East. RFV virus (RVFV) possesses a single-stranded tripartite RNA genome of negative/ambisense polarity. The S segment utilizes the ambisense strategy and codes for two proteins, the N nucleoprotein and the nonstructural NSs protein, in opposite orientations. The two open reading frames (ORFs) are separated by an intergenic r ...201121917943
field evaluation of a wicking assay for the rapid detection of rift valley fever viral antigens in mosquitoes.rift valley fever virus (rvfv) causes outbreaks of severe disease in domestic ungulates as well as humans in africa. there is a concern that outbreaks of rift valley fever may continue and that this virus may spread into regions where it had not previously been detected. surveillance and rapid detection are critical to the initiation of an effective disease control program. here we report on the field evaluation in kenya of the vectortest rvfv antigen assay, modeled on the vectest assay for west ...201122329268
potential for canadian mosquitoes to transmit rift valley fever virus.the rapid spread of west nile viral activity across north america since its discovery in 1999 illustrates the potential for an exotic arbovirus to be introduced and become widely established across north america. rift valley fever virus (rvfv) has been responsible for large outbreaks in africa that have resulted in hundreds of thousands of human infections and major economic disruption due to loss of livestock and to trade restrictions. however, little is known about the potential for mosquitoes ...201122329267
arbovirus prevalence in mosquitoes, kenya.few studies have investigated the many mosquito species that harbor arboviruses in kenya. during the 2006-2007 rift valley fever outbreak in north eastern province, kenya, exophilic mosquitoes were collected from homesteads within 2 affected areas: gumarey (rural) and sogan-godud (urban). mosquitoes (n = 920) were pooled by trap location and tested for rift valley fever virus and west nile virus. the most common mosquitoes trapped belonged to the genus culex (75%). of 105 mosquito pools tested, ...201121291594
[rift valley fever].rift valley fever (rvf) is a zoonotic arbovirosis. among animals, it mainly affects ruminants, causing abortions in gravid females and mortality among young animals. in humans, rvf virus infection is usually asymptomatic or characterized by a moderate fever. however, in 1 to 3% of cases, more severe forms of the disease (hepatitis, encephalitis, retinitis, hemorrhagic fever) can lead to the death of infected individuals or to major sequels. the rvf virus (bunyaviridae, genus phlebovirus) was ide ...201121295425
[severe presentations of rift valley fever in madagascar].the authors describe clinical and epidemiologic characteristics of severe presentations of rift valley fever (rvf) during the 2008 epidemic in madagascar.201121295426
simultaneous detection of rift valley fever, bluetongue, rinderpest, and peste des petits ruminants viruses by a single-tube multiplex reverse transcriptase-pcr assay using a dual-priming oligonucleotide system.the aim of this study was to develop a highly sensitive and specific one-step multiplex reverse transcriptase pcr assay for the simultaneous and differential detection of rift valley fever virus (rvfv), bluetongue virus (btv), rinderpest virus (rpv), and peste des petits ruminants virus (pprv). these viruses cause mucosal lesions in cattle, sheep, and goats, and they are difficult to differentiate from one another based solely on their clinical presentation in suspected disease cases. in this st ...201121307219
host genetic variation in susceptibility to punta toro virus.infection of small laboratory animals by punta toro virus (ptv), family bunyaviridae, genus phlebovirus, is a model for the study of the human pathogen rift valley fever virus (rvfv). we have identified inbred mouse strains with significant differences in host response to the adames strain of ptv. nine inbred strains of mice representing major branches in the mus musculus phylogeny were inoculated subcutaneously with a high dose of ptv in survival experiments. two inbred strains of mice, nzw/lac ...201121320557
quantitative analysis of particles, genomes and infectious particles in supernatants of haemorrhagic fever virus cell cultures.information on the replication of viral haemorrhagic fever viruses is not readily available and has never been analysed in a comparative approach. here, we compared the cell culture growth characteristics of haemorrhagic fever viruses (hfv), of the arenaviridae, filoviridae, bunyaviridae, and flavivridae virus families by performing quantitative analysis of cell culture supernatants by (i) electron microscopy for the quantification of virus particles, (ii) quantitative real time pcr for the quan ...201121349180
prevalence of rift valley fever infection in ruminants in madagascar after the 2008 outbreak.a rift valley fever (rvf) outbreak occurred in madagascar from january to may 2008. the objectives of this study were (1) to assess the current and past circulation of rvf virus (rvfv) in livestock in madagascar and (2) to evaluate the extent and magnitude of the 2008 rvf outbreak in livestock. the results of a country-wide serosurvey conducted in august 2008 on small and large ruminants are reported here. the study included 3437 cattle and 989 small ruminants (227 sheep and 762 goats) sampled i ...201121395414
measuring the burden of arboviral diseases: the spectrum of morbidity and mortality from four prevalent infections. 201121219615
comparative production analysis of three phlebovirus nucleoproteins under denaturing or non-denaturing conditions for crystallographic studies.nucleoproteins (nps) encapsidate the phlebovirus genomic (-)rna. upon recombinant expression, nps tend to form heterogeneous oligomers impeding characterization of the encapsidation process through crystallographic studies. to overcome this problem, we set up a standard protocol in which production under both non-denaturing and denaturing/refolding conditions can be investigated and compared. the protocol was applied for three phlebovirus nps, allowing an optimized production strategy for each o ...201121245924
rift valley fever: recent insights into pathogenesis and prevention.rift valley fever virus (rvfv) is a zoonotic pathogen that primarily affects ruminants but can also be lethal in humans. a negative-stranded rna virus of the family bunyaviridae, this pathogen is transmitted mainly via mosquito vectors. rvfv has shown the ability to inflict significant damage to livestock and is also a threat to public health. while outbreaks have traditionally occurred in sub-saharan africa, recent outbreaks in the middle east have raised awareness of the potential of this viru ...201121450816
rift valley fever virus infection in african buffalo (syncerus caffer) herds in rural south africa: evidence of interepidemic transmission.rift valley fever virus (rvfv) is an emerging biodefense pathogen that poses significant threats to human and livestock health. to date, the interepidemic reservoirs of rvfv are not well defined. in a longitudinal survey of infectious diseases among african buffalo during 2000-2006, 550 buffalo were tested for antibodies against rvfv in 820 capture events in 302 georeferenced locations in kruger national park, south africa. overall, 115 buffalo (21%) were seropositive. seroprevalence of rvfv was ...201121460024
genetic evidence for rift valley fever outbreaks in madagascar resulting from virus introductions from the east african mainland rather than enzootic maintenance.rift valley fever virus (rvfv), a mosquito-borne phlebovirus, has been detected in madagascar since 1979 with occasional outbreaks. in 2008-2009, a large rvfv outbreak was detected in malagasy livestock and humans during two successive rainy seasons. to determine whether cases were due to enzootic maintenance of virus within madagascar or importation from the east african mainland, nine rvfv whole genomic sequences were generated for viruses from the 1991 and 2008 malagasy outbreaks. bayesian co ...201121507967
nss protein of rift valley fever virus promotes post-translational downregulation of the tfiih subunit p62.rift valley fever virus (rvfv, family bunyaviridae, genus phlebovirus) is an important emerging pathogen of humans and ruminants. its nss protein has previously been identified as a major virulence factor that suppresses host defense through three distinct mechanisms: it directly inhibits ifn-β promoter activity, it promotes the degradation of double-stranded rna-dependent protein kinase (pkr) and it suppresses host transcription by disrupting the assembly of the basal transcription factor tfiih ...201121543505
rift valley fever epidemiology, surveillance, and control: what have models contributed?abstract background: rift valley fever (rvf) is an emerging vector-borne zoonotic disease that represents a threat to human health, animal health, and livestock production, particularly in africa. the epidemiology of rvf is not well understood, so that forecasting rvf outbreaks and carrying out efficient and timely control measures remains a challenge. various epidemiological modeling tools have been used to increase knowledge on rvf epidemiology and to inform disease management policies. aim: t ...201121548763
lymphoplasmacytic endotheliitis and anterior uveitis in sheep infected experimentally with rift valley fever virus.lymphoplasmacytic endotheliitis and anterior uveitis was diagnosed in four lambs infected experimentally with field isolates of rift valley fever virus (rvfv). formalin-fixed and paraffin wax-embedded tissue from these animals was investigated by histopathology and quantitative real time reverse transcriptase polymerase chain reaction. to our knowledge, this is the first pathological description of this ocular manifestation of rvfv infection in ruminants, although these lesions have been describ ...201121601870
infection with a plant virus modifies vector feeding behavior.vector infection by some animal-infecting parasites results in altered feeding that enhances transmission. modification of vector behavior is of broad adaptive significance, as parasite fitness relies on passage to a new host, and vector feeding is nearly always essential for transmission. although several plant viruses infect their insect vectors, we have shown that vector infection by a plant virus alters feeding behavior. here we show that infection with tomato spotted wilt virus (tswv), type ...201121606372
mosquito species abundance and diversity in malindi, kenya and their potential implication in pathogen transmission.mosquitoes (diptera: culicidae) are important vectors of human disease-causing pathogens. mosquitoes are found both in rural and urban areas. deteriorating infrastructure, poor access to health, water and sanitation services, increasing population density, and widespread poverty contribute to conditions that modify the environment, which directly influences the risk of disease within the urban and peri-urban ecosystem. the objective of this study was to evaluate the mosquito vector abundance and ...201121626425
host alternation is necessary to maintain the genome stability of rift valley fever virus.most arthropod-borne viruses (arboviruses) are rna viruses, which are maintained in nature by replication cycles that alternate between arthropod and vertebrate hosts. arboviruses appear to experience lower rates of evolution than rna viruses that replicate in a single host. this genetic stability is assumed to result from a fitness trade-off imposed by host alternation, which constrains arbovirus genome evolution. to test this hypothesis, we used rift valley fever virus (rvfv), an arbovirus tha ...201121629727
parenteral vaccination of mammalian livestock with newcastle disease virus-based vector vaccines offers optimal efficacy and safety.newcastle disease virus (ndv) is an avian virus that is being evaluated as a vaccine vector for the delivery of foreign genes in mammals. the use of ndv as a vaccine vector in these species offers two major advantages. first, ndv is highly attenuated in mammals, rendering its use inherently safe. second, mammals lack pre-existing ndv immunity, which minimizes the risk of vaccination failure. ndv-vector vaccines are generally administered to mammals via the respiratory route. we recently showed t ...201121636990
alteration in superoxide dismutase 1 causes oxidative stress and p38 mapk activation following rvfv infection.rift valley fever (rvf) is a zoonotic disease caused by rift valley fever virus (rvfv). rvfv is a category a pathogen that belongs to the genus phlebovirus, family bunyaviridae. understanding early host events to an infectious exposure to rvfv will be of significant use in the development of effective therapeutics that not only control pathogen multiplication, but also contribute to cell survival. in this study, we have carried out infections of human cells with a vaccine strain (mp12) and virul ...201121655261
wicking assay for the rapid detection of rift valley fever viral antigens in mosquitoes (diptera: culicidae).rift valley fever virus (rvfv) causes outbreaks of severe disease in domestic ungulates as well as humans in africa. there is a logical concern that rvfv could be introduced into the americas and cause significant health and economic damage based on the precedent of the introduction and spread of west nile virus (wnv). unfortunately, there are currently no licensed diagnostic assays available for rvfv in the americas. in this work, we report on the ability of a novel dipstick assay, vectortest r ...201121661324
safety and efficacy of rift valley fever smithburn and clone 13 vaccines in calves.two modified live attenuated vaccines against the disease rift valley fever (rvf) have been tested for safety and efficacy in young calves. the rvf smithburn vaccine produced in south africa and used successfully to prevent and control the disease in endemic sub-saharan countries was compared to the candidate vaccine rvf clone 13. five sero-negative calves per vaccine group were vaccinated with a single dose of each vaccine and tested for antibody response. all vaccinated calves were challenged ...201121664400
the pathogenesis of rift valley fever.rift valley fever (rvf) is an emerging zoonotic disease distributed in sub-saharan african countries and the arabian peninsula. the disease is caused by the rift valley fever virus (rvfv) of the family bunyaviridae and the genus phlebovirus. the virus is transmitted by mosquitoes, and virus replication in domestic ruminant results in high rates of mortality and abortion. rvfv infection in humans usually causes a self-limiting, acute and febrile illness; however, a small number of cases progress ...201121666766
protection of mp-12-vaccinated rhesus macaques against parenteral and aerosol challenge with virulent rift valley fever virus.to test safety and efficacy of the rift valley fever mp-12 (rvf mp-12) vaccine, 9 healthy adult rhesus macaques, weighing 5-10 kg, were inoculated intramuscularly with 6 × 10(3) plaque forming units (pfus) of mp-12 vaccine. the monkeys developed neutralizing antibody responses with no adverse effects other than a transient, low-titer viremia in 3 monkeys. four vaccinated animals challenged intravenously with 3 × 10(6) pfus of virulent rift valley fever virus strain zh-501 (rvfv zh-501) at 126 ...201121673033
arbovirus vaccines; opportunities for the baculovirus-insect cell expression system.the baculovirus-insect cell expression system is a well-established technology for the production of heterologous viral (glyco)proteins in cultured cells, applicable for basic scientific research as well as for the development and production of vaccines and diagnostics. arboviruses form an emerging group of medically important viral pathogens that are transmitted to humans and animals via arthropod vectors, mostly mosquitoes, ticks or midges. few arboviral vaccines are currently available, but t ...201121784227
potential effects of rift valley fever in the united states.rift valley fever virus (rvfv) has been the cause of disease outbreaks throughout africa and the arabian peninsula, and the infection often results in heavy economic costs through loss of livestock. if rvfv, which is common to select agent lists of the us department of health and human services and the us department of agriculture, entered the united states, either by accidental or purposeful means, the effects could be substantial. a group of subject matter experts met in december 2009 to discu ...201121801607
creation of a recombinant rift valley fever virus with a two-segmented genome.rift valley fever virus (rvfv; family bunyaviridae) is a clinically important, mosquito-borne pathogen of both livestock and humans, which is found mainly in sub-saharan africa and the arabian peninsula. rvfv has a tri-segmented ssrna genome. the l and m segments are negative-sense and encode the l protein (viral polymerase) on the l segment, and the virion glycoproteins gn and gc as well as two other proteins, nsm and 78k, on the m segment. the s segment uses an ambisense coding strategy to exp ...201121795328
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