decision-support tool for prevention and control of rift valley fever epizootics in the greater horn of 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
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
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
interview with dr. anthony r. fooks. interview by vicki glaser. 201020854027
toscana virus induces interferon although its nss protein reveals antagonistic activity.toscana virus (tosv) is a phlebotomus-transmitted virus that belongs to the family bunyaviridae and causes widespread infections in humans; about 30 % of these cases result in aseptic meningitis. in the present study, it was shown that tosv is an inducer of beta interferon (ifn-β), although its non-structural protein (nss) could inhibit the induction of ifn-β if expressed in a heterologous context. a recombinant rift valley fever virus expressing the tosv nss could suppress ifn-β expression in i ...201120861320
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 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 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
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
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
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
immunogenicity and safety of an inactivated rift valley fever vaccine in a 19-year investigational, formalin-inactivated rift valley fever (rvf) vaccine, known as the salk institute-government services division (tsi-gsd) 200 vaccine, was administered to 1860 at-risk subjects (5954 doses) between 1986 and 2004 as a three-dose primary series (days 0, 7, and 28) followed by booster doses as needed for declining titers. an initial positive serological response (prnt(80)=1:40) to the primary series was observed in 90% of subjects. estimate of the prnt(80) response half-life in i ...201121354483
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
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
efficient cellular release of rift valley fever virus requires genomic rna.the rift valley fever virus is responsible for periodic, explosive epizootics throughout sub-saharan africa. the development of therapeutics targeting this virus is difficult due to a limited understanding of the viral replicative cycle. utilizing a virus-like particle system, we have established roles for each of the viral structural components in assembly, release, and virus infectivity. the envelope glycoprotein, gn, was discovered to be necessary and sufficient for packaging of the genome, n ...201121445316
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
a dna vaccine encoding ubiquitinated rift valley fever virus nucleoprotein provides consistent immunity and protects ifnar(-/-) mice upon lethal virus challenge.current vaccine candidates against rift valley fever virus (rvfv) incorporate the viral structural glycoproteins as antigens, since triggering antibody responses against them usually correlates with protection. here, we have focused solely on the nucleoprotein of rvfv as a potential target for vaccine development. previous studies in mouse models have already demonstrated that rvfv nucleoprotein can elicit partial protection when administered by means of a dna vaccine or in recombinant, soluble, ...201121549790
virus isolations and high population density implicate culex antennatus (becker) (diptera: culicidae) as a vector of rift valley fever virus during an outbreak in the nile delta of june, 2003, egypt's hospital-based electronic disease surveillance system began to record increased cases of acute febrile illness from governorates in the nile delta. in response to a request for assistance from the egyptian ministry of health and the world health organization (who), the u.s. naval medical research unit no. 3 (namru-3) provided assistance in identifying the cause and extent of this outbreak. testing of human clinical samples (n=375) from nine governorates in egypt identified ...201121570939
the hexamer structure of the rift valley fever virus nucleoprotein suggests a mechanism for its assembly into ribonucleoprotein complexes.rift valley fever virus (rvfv), a phlebovirus with a genome consisting of three single-stranded rna segments, is spread by infected mosquitoes and causes large viral outbreaks in africa. rvfv encodes a nucleoprotein (n) that encapsidates the viral rna. the n protein is the major component of the ribonucleoprotein complex and is also required for genomic rna replication and transcription by the viral polymerase. here we present the 1.6 å crystal structure of the rvfv n protein in hexameric form. ...201121589902
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 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
mucosal immunization of rhesus macaques with rift valley fever mp-12 vaccine.rhesus macaques given 5 × 10(4) or 1 × 10(5) plaque-forming units (pfu) of rift valley fever (rvf) mp-12 vaccine by oral, intranasal drops, or small particle aerosol showed no adverse effects up to 56 days after administration. all monkeys given the vaccine by aerosol or intranasal drops developed 80% plaque reduction neutralization titers of = 1:40 by day 21 after inoculation. only 2 of 4 monkeys given the vaccine by oral instillation developed detectable neutralizing antibodies. all monkeys va ...201121791664
outbreak of rift valley fever affecting veterinarians and farmers in south africa, 2008.during 2008, rift valley fever (rvf) virus re-emerged in south africa as focal outbreaks in several provinces.201121786732
dc-sign as a receptor for phleboviruses.during natural transmission, bunyaviruses are introduced into the skin through arthropod bites, and dermal dendritic cells (dcs) are the first to encounter incoming viruses. dc-sign is a c-type lectin highly expressed on the surface of dermal dcs. we found that several arthropod-borne phleboviruses (bunyaviridae), including rift valley fever and uukuniemi viruses, exploit dc-sign to infect dcs and other dc-sign-expressing cells. dc-sign binds the virus directly via interactions with high-mannose ...201121767814
rift valley fever in ruminants, republic of comoros, the editor: rift valley fever (rvf) is caused by a phlebovirus (family bunyaviridae) transmitted by a wide range of mosquitoes (1). this zoonotic disease is present in africa, the middle east, and madagascar. infections by rvf virus (rvfv) in ruminants cause massive abortions in livestock and high death rates in young animals, which result in major economic consequences. humans are infected by mosquito bites, contact, or inhalation of aerosols. rvf is frequently unapparent or mild for humans, ...201121762604
common, emerging, vector-borne and infrequent abortogenic virus infections of cattle.this review deals with the aetiology and the diagnosis of bovine viral abortion. while the abortion rates on beef and dairy cattle farms usually do not exceed 10%, significant economic losses because of abortion storms may be encountered. determining the cause of abortions is usually a challenge, and it generally remains obscure in more than 50% of the necropsy submitted foetuses. bovine viral diarrhoea virus and bovine herpesvirus-1 are the most common viruses causally associated with bovine ab ...201121733134
validation of an igm antibody capture elisa based on a recombinant nucleoprotein for identification of domestic ruminants infected with rift valley fever virus.the presence of competent vectors in some countries currently free of rift valley fever (rvf) and global changes in climate, travel and trade have increased the risk of rvf spreading to new regions and have emphasised the need for accurate and reliable diagnostic tools for early diagnosis during rvf outbreaks. highly sensitive viral detection systems like pcr have a limited use during outbreaks because of the short duration of viraemia, whereas antibodies like specific igm which are serological ...201121827790
observations on rift valley fever virus and vaccines in egypt.abstract: rift valley fever virus (rvfv, genus: phlebovirus, family: bunyaviridae), is an arbovirus which causes significant morbidity and mortality in animals and humans. rvfv was introduced for the first time in egypt in 1977. in endemic areas, the insect vector control and vaccination is considering appropriate measures if applied properly and the used vaccine is completely safe and the vaccination programs cover all the susceptible animals. egypt is importing livestock and camels from the af ...201122152149
Recent advances in the molecular and cellular biology of bunyaviruses.The family Bunyaviridae of segmented, negative-stranded RNA viruses includes over 350 members that infect a bewildering variety of animals and plants. Many of these bunyaviruses are the causative agents of serious disease in their respective hosts, and are classified as emerging viruses because of their increased incidence in new populations and geographical locations throughout the world. Emerging bunyaviruses, such as Crimean-Congo hemorrhagic fever virus, tomato spotted wilt virus and Rift Va ...201121865443
an unexpected recurrent transmission of rift valley fever virus in cattle in a temperate and mountainous area of madagascar.rift valley fever is an acute, zoonotic viral disease of domestic ruminants, caused by a phlebovirus (bunyaviridae family). a large outbreak occurred in madagascar in 2008-2009. the goal of the present study was to evaluate the point prevalence of antibodies against rift valley fever virus (rvfv) in cattle in the anjozorobe district, located in the wet and temperate highland region of madagascar and yet heavily affected by the disease, and analyse environmental and trade factors potentially link ...201122206026
creation of a nonspreading rift valley fever virus.rift valley fever virus (rvfv) is a mosquito-borne zoonotic bunyavirus of the genus phlebovirus and a serious human and veterinary pathogen. rvfv contains a three-segmented rna genome, which is comprised of the large (l), medium (m), and small (s) segments. the proteins that are essential for genome replication are encoded by the l and s segments, whereas the structural glycoproteins are encoded by the m segment. we have produced bhk replicon cell lines (bhk-rep) that maintain replicating l and ...201121957302
Animal models of Rift Valley fever virus infection.Emerging and naturally occurring infectious diseases from bacterial and viral sources are constantly threatening humans and livestock. Recently, a variety of infectious diseases have emerged into previously disease-free areas, resulting in new epidemics. Consequently, governmental agencies and researchers in the area of biomedical research have started designing ways to prevent their further spread. Ongoing research activities are focused on developing therapeutic and prophylactic interventions ...201122086058
anti-nucleocapsid protein immune responses counteract pathogenic effects of rift valley fever virus infection in mice.the known virulence factor of rift valley fever virus (rvfv), the nss protein, counteracts the antiviral effects of the type i interferon response. in this study we evaluated the expression of several genes in the liver and spleen involved in innate and adaptive immunity of mice immunized with a rvfv recombinant nucleocapsid protein (recnp) combined with alhydrogel adjuvant and control animals after challenge with wild type rvfv. mice immunized with recnp elicited an earlier ifnβ response after ...201121949840
using next generation sequencing to identify yellow fever virus in october and november 2010, hospitals in northern uganda reported patients with suspected hemorrhagic fevers. initial tests for ebola viruses, marburg virus, rift valley fever virus, and crimean congo hemorrhagic fever virus were negative. unbiased pcr amplification of total rna extracted directly from patient sera and next generation sequencing resulted in detection of yellow fever virus and generation of 98% of the virus genome sequence. this finding demonstrated the utility of next generati ...201221962764
The 2007 Rift Valley fever outbreak in Sudan.Rift Valley fever (RVF) is a neglected, emerging, mosquito-borne disease with severe negative impact on human and animal health and economy. RVF is caused by RVF virus (RVFV) affecting humans and a wide range of animals. The virus is transmitted through bites from mosquitoes and exposure to viremic blood, body fluids, or tissues of infected animals. During 2007 a large RVF outbreak occurred in Sudan with a total of 747 confirmed human cases including 230 deaths (case fatality 30.8%); although it ...201121980543
detection of puumala and rift valley fever virus by quantitative rt-pcr and virus viability tests in samples of blood dried and stored on filter paper.haemorrhagic fever viruses cause emerging infections worldwide, and blood or serum is the main sample used for diagnosis. however, storage and transportation of such samples from remote areas to regional laboratories may be complicated and expensive. in this study, a novel approach was evaluated for the detection of puumala hantavirus (puuv) rna and rift valley fever virus (rvfv) rna. whole-blood samples spiked with viable virus particles were tested in parallel with clinical samples from patien ...201121946288
rift valley fever virus vaccine lacking the nss and nsm genes is safe, nonteratogenic, and confers protection from viremia, pyrexia, and abortion following challenge in adult and pregnant sheep.rift valley fever virus (rvfv) is a mosquito-borne human and veterinary pathogen causing large outbreaks of severe disease throughout africa and the arabian peninsula. safe and effective vaccines are critically needed, especially those that can be used in a targeted one-health approach to prevent both livestock and human disease. we report here on the safety, immunogenicity, and efficacy of the δnss-δnsm recombinant rvfv (rrvfv) vaccine (which lacks the nss and nsm virulence factors) in a total ...201121976656
molecular epidemiology of rift valley fever virus.phylogenetic relationships were examined for 198 rift valley fever virus isolates and 5 derived strains obtained from various sources in saudi arabia and 16 countries in africa during a 67-year period (1944-2010). a maximum-likelihood tree prepared with sequence data for a 490-nt section of the gn glycoprotein gene showed that 95 unique sequences sorted into 15 lineages. a 2010 isolate from a patient in south africa potentially exposed to co-infection with live animal vaccine and wild virus was ...201122172568
the status of rift valley fever in animals in saudi arabia: a mini august-september 2000, an overwhelming outbreak of rift valley fever (rvf) struck the southwestern part of saudi arabia and adjoining yemeni territories. during the outbreak, which was the first ever to be recorded outside africa, around 40,000 animals, mostly sheep and goats, died or aborted and 883 cases, with 124 deaths, were recorded among humans in saudi arabia. an additional 1328 human cases, with 166 deaths, were concurrently recorded in northwestern yemen. vector studies in saudi arab ...201121923257
The Nonstructural Protein NSs Induces a Variable Antibody Response in Domestic Ruminants Naturally Infected with Rift Valley Fever Virus.Rift Valley fever (RVF) is an emerging zoonosis in Africa which has spread to Egypt, the Arabian Peninsula, Madagascar, and Comoros. RVF virus (RVFV) (Bunyaviridae family, Phlebovirus genus) causes a wide range of symptoms in humans, from benign fever to fatal hemorrhagic fever. Ruminants are severely affected by the disease, which leads to a high rate of mortality in young animals and to abortions and teratogenesis in pregnant females. Diagnostic tests include virus isolation and genome or anti ...201222072723
rift valley fever virus inhibits a pro-inflammatory response in experimentally infected human monocyte derived macrophages and a pro-inflammatory cytokine response may be associated with patient survival during natural infection.rift valley fever virus (rvfv) causes significant morbidity and mortality in humans and livestock throughout africa and the middle east. the clinical disease ranges from mild febrile illness, to hepatitis, retinitis, encephalitis and fatal hemorrhagic fever. rvfv nss protein has previously been shown to interfere in vitro with the interferon response, and rvfv lacking the nss protein is attenuated in several animal models. monocytes and macrophages are key players in the innate immune response v ...201222018491
identification of an antioxidant small-molecule with broad-spectrum antiviral activity.the highly lethal filoviruses, ebola and marburg cause severe hemorrhagic fever in humans and non-human primates. to date there are no licensed vaccines or therapeutics to counter these infections. identifying novel pathways and host targets that play an essential role during infection will provide potential targets to develop therapeutics. small molecule chemical screening for ebola virus inhibitors resulted in identification of a compound nsc 62914. the compound was found to exhibit anti-filov ...201222027648
development and evaluation of one-step rrt-pcr and immunohistochemical methods for detection of rift valley fever virus in biosafety level 2 diagnostic laboratories.rift valley fever virus (rvfv) is a zoonotic insect transmitted virus endemic to africa and the arabian peninsula. infection causes abortions and high mortality in newborn ruminants. the overall human infection rate is <1%; however, fatality rates in those with severe clinical disease have been reported as high as 29%. the potential of rvfv as a bioterrorism agent and/or being accidentally introduced into north america is widely recognized. currently, regional veterinary biosafety level 2 (bsl-2 ...201122172972
development of a novel non-human primate model for rift valley fever.rift valley fever virus (rvfv) can cause severe human disease characterized by either acute-onset hepatitis, or delayed-onset encephalitis, or retinitis and blindness, or a hemorrhagic syndrome. the existing non-human primate (nhp) model for rvf utilizes an intravenous exposure route in rhesus macaques (macaca mulatta). severe disease in these animals is infrequent and large cohorts are needed to observe significant morbidity and mortality. to overcome these drawbacks, we evaluated the infectivi ...201122156530
competitive elisa for the detection of antibodies to rift valley fever virus in goat and cattle.rift valley fever virus (rvfv) is one of the important emerging viral diseases of serious impact in public health and animal hygiene both in human and animal industry. in this study, we developed monoclonal antibody-based competitive elisa for the detection of antibodies to rvfv in goat and cattle. the recombinant n protein of rvfv was expressed in e. coli with six-histidine tag and the purified n protein was used for detecting antigen with competitive monoclonal antibody against rvfv antibodies ...201122020149
A Review of Zoonotic Disease Surveillance Supported by the Armed Forces Health Surveillance Center.The Armed Forces Health Surveillance Center (AFHSC), Division of Global Emerging Infections Surveillance and Response System conducts disease surveillance through a global network of US Department of Defense research laboratories and partnerships with foreign ministries of agriculture, health and livestock development in over 90 countries worldwide. In 2010, AFHSC supported zoonosis survey efforts were organized into four main categories: (i) development of field assays for animal disease survei ...201122128834
Generation and characterization of a recombinant Rift Valley fever virus expressing a V5 epitope-tagged RNA-dependent RNA polymerase.The viral RNA-dependent RNA polymerase (RdRp; L protein) of Rift Valley fever virus (RVFV; family Bunyaviridae) is a 238 kDa protein that is crucial for the life cycle of the virus, as it catalyses both transcription of viral mRNAs and replication of the tripartite genome. Despite its importance, little is known about the intracellular distribution of the polymerase or its other roles during infection, primarily because of lack of specific antibodies that recognize L protein. To begin to address ...201121900422
using reverse genetics to manipulate the nss gene of the rift valley fever virus mp-12 strain to improve vaccine safety and efficacy.rift valley fever virus (rvfv), which causes hemorrhagic fever, neurological disorders or blindness in humans, and a high rate abortion and fetal malformation in ruminants, has been classified as a hhs/usda overlap select agent and a risk group 3 pathogen. it belongs to the genus phlebovirus in the family bunyaviridae and is one of the most virulent members of this family. several reverse genetics systems for the rvfv mp-12 vaccine strain as well as wild-type rvfv strains, including zh548 and zh ...201122083261
tissue tropism and target cells of nss-deleted rift valley fever virus in live immunodeficient mice.rift valley fever virus (rvfv) causes disease in livestock and humans. it can be transmitted by mosquitoes, inhalation or physical contact with the body fluids of infected animals. severe clinical cases are characterized by acute hepatitis with hemorrhage, meningoencephalitis and/or retinitis. the dynamics of rvfv infection and the cell types infected in vivo are poorly understood.201122163058
postepidemic analysis of rift valley fever virus transmission in northeastern kenya: a village cohort endemic areas, rift valley fever virus (rvfv) is a significant threat to both human and animal health. goals of this study were to measure human anti-rvfv seroprevalence in a high-risk area following the 2006-2007 kenyan rift valley fever (rvf) epidemic, to identify risk factors for interval seroconversion, and to monitor individuals previously exposed to rvfv in order to document the persistence of their anti-rvfv antibodies.201121858236
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
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
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
characterization of rna aptamers directed against the nucleocapsid protein of rift valley fever virus.nucleocapsid protein (n) is an essential rna binding protein in many rna viruses. during replication, n protein encapsidates viral genomic and antigenomic rna, but not viral mrna or other cellular rnas. to discriminate between different species of rna in a host cell, it is likely that n interacts with specific sequences and/or secondary structures on its target rna. in this study, we explore the rna binding properties of n using both natural and artificially selected rnas as ligands. we found th ...201222252167
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
re-emergence of rift valley fever virus in barkedji (senegal, west africa) in 2002-2003: identification of new vectors and epidemiological implications.the rift valley fever virus (rvfv) is a threat that must not be neglected, as the consequences of rvfv are dramatic, both for human and animal health. this virus is a zoonotic virus that already has demonstrated a real capacity for re-emerging after long periods of silence, as observed in barkedji (senegal, west africa) in 2002. in this article we present the 2nd emergence in barkedji after the 1st manifestation in 1993, and for the 1st time the circulation of rvfv during 2 consecutive years amo ...201223833896
virus-like particle-based countermeasures against rift valley fever virus.rift valley fever virus (rvfv) is an arbovirus that causes significant morbidity and mortality in both humans and livestock. with increased world travel and the threat of bioterrorism, there is a real risk of rvfv spreading to naïve geographical areas (trans. r. soc. trop. med. hyg., 73, 1979, 618; mmwr morb. mortal. wkly rep., 49, 2000, 905). the introduction of rvfv would cause critical public health, agricultural and economic damage. despite the clear need for an efficacious vaccine, there ar ...201222958258
evolutionary and molecular analysis of the emergent severe fever with thrombocytopenia syndrome 2009, a novel bunyavirus, called severe fever with thrombocytopenia syndrome virus (sftsv) was identified in the vicinity of huaiyangshan, china. clinical symptoms of this zoonotic virus included severe fever, thrombocytopenia, and leukocytopenia, with a mortality rate of ~10%. by the end of 2011 the disease associated with this pathogen had been reported from eleven chinese provinces and human-to-human transmission suspected. however, current understanding of the evolution and molecular epid ...201223438426
members of the culex pipiens complex as vectors of viruses.members of the culex pipiens complex have been implicated as vectors of a number of arboviruses including st. louis encephalitis, west nile, sindbis, and rift valley fever viruses. for some viruses, such as west nile virus, laboratory studies have indicated that various members of this complex have a similar ability to become infected with and transmit virus, thus providing evidence for the similarity among the various members of this complex. on the other hand, although strains of cx. pipiens f ...201223401952
introduction to the symposium global perspective on the culex pipiens complex in the 21st century: the interrelationship of culex pipiens, quinquefasciatus, molestus and others.mosquitoes in the culex pipiens complex, including culex pipiens, cx. quinquefasciatus, and cx. molestus, are important pest species and vectors of human and animal diseases throughout the world's tropical, temperate, and holarctic regions. diseases transmitted by member of the pipiens complex include: st. louis encephalitis and west nile virus in north america, west nile virus on several other continents, rift valley fever in africa, lymphatic filariasis caused by wuchereria bancrofti in the tr ...201223401940
Displaying items 701 - 800 of 1560