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effect of dose on house finch infection with western equine encephalomyelitis and st. louis encephalitis viruses.house finches, carpodacus mexicanus, were experimentally infected with high and standard doses of western equine encephalomyelitis virus (weev) or st. louis encephalitis virus (slev) to determine whether high doses would produce an elevated viremia response and a high frequency of chronic infections. finches inoculated with approximately100,000 plaque forming units (pfu) of weev or slev produced viremia and antibody responses similar to those in finches inoculated with approximately 100 pfu of w ...200415535631
western equine encephalomyelitis virus infection affects the life table characteristics of culex tarsalis (diptera: culicidae).the life table attributes of culex tarsalis coquillett females infected experimentally by feeding on 4 and 6 log10 plaque-forming units (pfu) of western equine encephalomyelitis virus (weev) per milliliter of heparinized chicken blood were compared with an uninfected control group. females continually were offered 10% sucrose and an oviposition substrate and daily a blood meal through a biomembrane feeder. mortality (dead females) and fecundity (female eggs per female) were monitored daily until ...200415535632
proteomics computational analyses suggest that the carboxyl terminal glycoproteins of bunyaviruses are class ii viral fusion protein (beta-penetrenes).the bunyaviridae family of enveloped rna viruses includes five genuses, orthobunyaviruses, hantaviruses, phleboviruses, nairoviruses and tospoviruses. it has not been determined which bunyavirus protein mediates virion:cell membrane fusion. class ii viral fusion proteins (beta-penetrenes), encoded by members of the alphaviridae and flaviviridae, are comprised of three antiparallel beta sheet domains with an internal fusion peptide located at the end of domain ii. proteomics computational analyse ...200415544707
duplex reverse transcription-pcr followed by nested pcr assays for detection and identification of brazilian alphaviruses and flaviviruses.a new approach was developed for the rapid detection and identification of brazilian alphaviruses and flaviviruses. the methodology involves the genus-specific detection of alphavirus and flavivirus by a duplex reverse transcription-pcr (d-rt-pcr), followed by multiplex nested pcr (m-n-pcr) or nested pcr (n-pcr) assays for species-specific identification. by this protocol, 25 arboviruses were specifically detected and identified. detection levels between 10(1.3) and 10(3.5) 50% tissue culture in ...200515695666
prophylaxis of acute respiratory virus infections using nucleic acid-based drugs.acute respiratory virus infections such as sars and pandemic influenza are highly contagious diseases that cause global crisis, and inflict severe human mortality and morbidity. vaccines against these viruses are either unavailable or do not provide adequate protection. in the absence of effective vaccines, nucleic acid-based immunomodulators have the potential to offer effective, broad-spectrum protection against these deadly pathogens. poly iclc and cpg oligonucleotides are promising gene-base ...200515755608
efficacy of dna vaccination against western equine encephalitis virus infection.the efficacy of a dna vaccine against western equine encephalitis (wee) infection in mice was evaluated. the 26s structural region was expressed, in vitro from an internal t7 promoter using a rabbit reticulysate transcription/translation system; and from a cmv promoter after transfection into vero cell monolayers. the proteins synthesized were reactive with anti-wee virus (weev) antibodies, both in western blot analysis and histochemical staining, respectively. when the dna vaccine plasmid, pvhx ...200515755611
dna shuffling and screening strategies for improving vaccine efficacy.the efficacy of vaccines can be improved by increasing their immunogenicity, broadening their crossprotective range, as well as by developing immunomodulators that can be coadministered with the vaccine antigen. one technology that can be applied to each of these aspects of vaccine development is molecularbreeding directed molecular evolution. essentially, this technology is used to evolve genes in vitro through an iterative process consisting of recombinant generation followed by selection of t ...200515812242
nucleic acid amplification assays for detection of la crosse virus rna.we report the development of nucleic acid sequence-based amplification (nasba) and quantitative real-time reverse transcription (rt)-pcr assays for the detection of la crosse (lac) virus in field-collected vector mosquito samples and human clinical samples. the sensitivities of these assays were compared to that of a standard plaque assay in vero cells. the nasba and quantitative real-time rt-pcr assays demonstrated sensitivities greater than that of the standard plaque assay. the specificities ...200515815013
antibody response to culex tarsalis salivary gland antigens among sentinel chickens in california.the arboviral surveillance program in california depends in part on sentinel chickens to detect western equine encephalomyelitis virus, st. louis encephalitis virus, and west nile virus activity. from 2000 through 2002, 1,578 serum specimens from 34 sentinel flocks in northern and southern california were tested for antibodies to culex tarsalis salivary gland antigens. sentinel chickens that were seropositive for mosquito salivary gland antigens were more likely to seroconvert to st. louis encep ...200515827292
birds, migration and emerging zoonoses: west nile virus, lyme disease, influenza a and enteropathogens.wild birds are important to public health because they carry emerging zoonotic pathogens, either as a reservoir host or by dispersing infected arthropod vectors. in addition, bird migration provides a mechanism for the establishment of new endemic foci of disease at great distances from where an infection was acquired. birds are central to the epidemiology of west nile virus (wnv) because they are the main amplifying host of the virus in nature. the initial spread of wnv in the u.s. along the ea ...200315931279
a simplified method for preparing eastern and western equine encephalomyelitis complement fixing antigens. 196715938267
aerosol exposure to western equine encephalitis virus causes fever and encephalitis in cynomolgus macaques.cynomolgus macaques were exposed by aerosol to a virulent strain of western equine encephalitis virus (weev). between 4 and 6 days after exposure, macaques had a significantly elevated temperature that lasted for 3-4 days. clinical signs of encephalitis began as the body temperature decreased, and then they rapidly increased in severity. cynomolgus macaques with clinical signs of encephalitis had elevated white cell counts in the blood caused mostly by increased numbers of segmented neutrophils ...200516136459
coltiviruses and seadornaviruses in north america, europe, and asia.coltiviruses are tickborne viruses of the genus coltivirus. the type species, colorado tick fever virus (from north america), has been isolated from patients with flulike syndromes, meningitis, encephalitis, and other severe complications. another coltivirus, eyach virus, has been isolated from ticks in france and germany and incriminated in febrile illnesses and neurologic syndromes. seadornaviruses are endemic in southeast asia, particularly indonesia and china. the prototype virus of the genu ...200516318717
host range, amplification and arboviral disease emergence.etiologic agents of arboviral diseases are primarily zoonotic pathogens that are maintained in nature in cycles involving arthropod transmission among a variety of susceptible reservoir hosts. in the simplest form of human exposure, spillover occurs from the enzootic cycle when humans enter zoonotic foci and/or enzootic amplification increases circulation near humans. examples include eastern (eeev) and western equine encephalitis viruses (weev), as well as west nile (wnv), st. louis encephaliti ...200516358422
[detection of sindbis virus-specific nucleic acid with sybr green i real time pcr assay].to develop a rapid, specific and sensitive method for detecting sindbis virus (sinv) with sybr green i real time pcr.200516415993
west nile virus epidemics in north america are driven by shifts in mosquito feeding behavior.west nile virus (wnv) has caused repeated large-scale human epidemics in north america since it was first detected in 1999 and is now the dominant vector-borne disease in this continent. understanding the factors that determine the intensity of the spillover of this zoonotic pathogen from birds to humans (via mosquitoes) is a prerequisite for predicting and preventing human epidemics. we integrated mosquito feeding behavior with data on the population dynamics and wnv epidemiology of mosquitoes, ...200616494532
pathological changes in brain and other target organs of infant and weanling mice after infection with non-neuroadapted western equine encephalitis virus.infant and weanling mice infected experimentally with non-neuroadapted western equine encephalitis virus exhibited a differing spectrum of target-organ pathology as well as a different clinical response. the infant mice sickened and died within 48 hr. pathological changes in this group were largely limited to such mesodermally derived tissues as muscle, cartilage, and bone marrow elements. the central nervous system was uninvolved, as were heart, lung, liver, and other body organs. the young adu ...197016557874
triaryl pyrazoline compound inhibits flavivirus rna replication.triaryl pyrazoline {[5-(4-chloro-phenyl)-3-thiophen-2-yl-4,5-dihydro-pyrazol-1-yl]-phenyl-methanone} inhibits flavivirus infection in cell culture. the inhibitor was identified through high-throughput screening of a compound library using a luciferase-expressing west nile (wn) virus infection assay. the compound inhibited an epidemic strain of wn virus without detectable cytotoxicity (a 50% effective concentration of 28 microm and a compound concentration of >or=300 microm required to reduce 50% ...200616569847
effects of temperature on the transmission of west nile virus by culex tarsalis (diptera: culicidae).culex tarsalis coquillett females were infected with the ny99 strain of west nile virus (family flaviviridae, genus flavivirus, wnv) and then incubated under constant temperatures of 10-30 degrees c. at selected time intervals, transmission was attempted using an in vitro capillary tube assay. the median time from imbibing an infectious bloodmeal until infected females transmitted wnv (median extrinsic incubation period, eip50) was estimated by probit analysis. by regressing the eip rate (invers ...200616619616
infectivity variation and genetic diversity among strains of western equine encephalitis virus.variation in infectivity and genetic diversity in the structural proteins were compared among eight strains of western equine encephalitis virus (weev) to investigate weev virulence at the molecular level. a lethal intranasal infectivity model of weev was developed in adult balb/c mice. all eight strains examined were 100 % lethal to adult mice in this model, but they varied considerably in the time to death. based on the time to death, the eight strains could be classified into two pathotypes: ...200616847131
alphavirus capsid protein helix i controls a checkpoint in nucleocapsid core assembly.the assembly of the alphavirus nucleocapsid core has been investigated using an in vitro assembly system. the c-terminal two-thirds of capsid protein (cp), residues 81 to 264 in sindbis virus (sinv), have been previously shown to have all the rna-cp and cp-cp contacts required for core assembly in vitro. helix i, which is located in the n-terminal dispensable region of the cp, has been proposed to stabilize the core by forming a coiled coil in the cp dimer formed by the interaction of residues 8 ...200616940497
functions of the stem region of the semliki forest virus fusion protein during virus fusion and assembly.membrane fusion of the alphaviruses is mediated by the e1 protein, a class ii virus membrane fusion protein. during fusion, e1 dissociates from its heterodimer interaction with the e2 protein and forms a target membrane-inserted e1 homotrimer. the structure of the homotrimer is that of a trimeric hairpin in which e1 domain iii and the stem region fold back toward the target membrane-inserted fusion peptide loop. the e1 stem region has a strictly conserved length and several highly conserved resi ...200616971447
role of california (callipepla californica) and gambel's (callipepla gambelii) quail in the ecology of mosquito-borne encephalitis viruses in california, usa.gambel's and california quail were infected repeatedly whenever western equine encephalomyelitis virus (weev), st. louis encephalitis virus (slev), and (wnv) west nile virus were active during summer in california. the timing of virus appearance and quail infection coincided well with the appearance of chicks in nature, leading us to hypothesize that large coveys containing these non-immune birds could be important in focal virus amplification in rural settings. however, experimental infection s ...200616989564
effects of time after infection, mosquito genotype, and infectious viral dose on the dynamics of culex tarsalis vector competence for western equine encephalomyelitis virus.the vector competence of culex tarsalis coquillett for the bfs 1703 strain of western equine encephalomyelitis virus (weev) changed significantly as a function of time after infection, mosquito genotype, and infectious virus dose. after ingesting a high virus dose (5 log10 plaque-forming units [pfu]/0.1 ml), female of the susceptible high virus producer (hvp) strain rapidly amplified the virus, developed a disseminated infection, and efficiently transmitted weev by 4 days postinfection (dpi). th ...200617019773
the old world and new world alphaviruses use different virus-specific proteins for induction of transcriptional shutoff.alphaviruses are widely distributed throughout the world. during the last few thousand years, the new world viruses, including venezuelan equine encephalitis virus (veev) and eastern equine encephalitis virus (eeev), evolved separately from those of the old world, i.e., sindbis virus (sinv) and semliki forest virus (sfv). nevertheless, the results of our study indicate that both groups have developed the same characteristic: their replication efficiently interferes with cellular transcription an ...200717108023
effect of exogenous interferon and an interferon inducer on western equine encephalitis virus disease in a hamster model.mice are used as models for western equine encephalitis virus (weev) infection, but high mortality is generally only seen with intracranial or intranasal challenge, while peripheral inoculation results in approximately 50% mortality and is not dose-dependent. hamsters were therefore studied as a model for weev infection. hamsters were highly sensitive to intraperitoneal (i.p.) infection with weev. disease progression was rapid, and virus titers in serum, brain, liver, and kidney of infected hams ...200717118420
capsid protein of eastern equine encephalitis virus inhibits host cell gene expression.eastern equine encephalitis virus (eeev) causes sporadic but often severe cases of human and equine neurological disease in north america. to determine how eeev may evade innate immune responses, we screened individual eeev proteins for the ability to rescue the growth of a newcastle disease virus expressing green fluorescent protein (ndv-gfp) from the antiviral effects of interferon (ifn). only expression of the eeev capsid facilitated ndv-gfp replication. inhibition of the antiviral effects of ...200717267491
ecological correlates of buggy creek virus infection in oeciacus vicarius, southwestern nebraska, 2004.buggy creek virus (family togaviridae, genus alphavirus, bcrv) is an alphavirus within the western equine encephalitis virus complex whose primary vector is the swallow bug, oeciacus vicarius horvath (hemiptera: cimicidae), an ectoparasite of the colonially nesting cliff swallow, petrochelidon pyrrhonota, that is also a frequent host for the virus. we investigated ecological correlates of bcrv infection in 100-bug pools at 14 different swallow colony sites in southwestern nebraska from summer 20 ...200717294919
vector competence of culiseta incidens and culex thriambus for west nile virus.the vector competence of culiseta incidens (thomson) and culex thriambus dyar for west nile virus (wnv) were compared to cx. quinquefasciatus say or cx. tarsalis coquillett and cx. stigmatasoma dyar collected concurrently in california. culiseta incidens were less susceptible to oral infection than cx. quinquefasciatus, but transmitted virus at a significantly higher rate, thereby yielding comparable population transmission rates. culex thriambus was equally susceptible to oral infection and tra ...200617304934
health evaluation of free-ranging and captive blue-fronted amazon parrots (amazona aestiva) in the gran chaco, bolivia.bolivia has a total of 47 species of psittacidae, seven of which have been identified in our study site, the semiarid gran chaco of the isoso. one species, the blue-fronted parrot (amazona aestiva), is frequently captured by local isoseño guaraní indians for exploitation on the national and international market. these birds are often temporarily housed in small villages under unhygienic conditions with poultry and other domestic species. on occasion, these parrots escape back to the wild. additi ...200517312715
serologic evidence of widespread everglades virus activity in dogs, florida.everglades virus (evev), an alphavirus in the venezuelan equine encephalitis complex, circulates among rodents and vector mosquitoes in florida and occasionally infects humans. it causes febrile disease, sometimes accompanied by neurologic manifestations. although previous surveys showed high seroprevalence in humans, evev infections may be underdiagnosed because the disease is not severe enough to warrant a clinic visit or the undifferentiated presentations complicate diagnosis. documented evev ...200617326938
does feeding on infected mosquitoes (diptera: culicidae) enhance the role of song sparrows in the transmission of arboviruses in california?song sparrows, melopiza melodia, inoculated subcutaneously with either western equine encephalomyelitis virus (family togaviridae, genus alphavirus, weev) or west nile virus (family flaviviridae, genus flavivirus, wnv) developed elevated viremias, and they were considered to be competent experimental hosts for both viruses. however, birds that ingested from three to 20 mosquitoes containing comparable amounts of either weev or wnv failed to become infected, indicating limited oral susceptibility ...200717427703
complete protection of mice against a lethal dose challenge of western equine encephalitis virus after immunization with an adenovirus-vectored vaccine.western equine encephalitis virus (weev) is an important pathogen for both humans and equines. the virus is also listed as a bioterrorism agent due to its ability for aerosol transmission with high mortality. no commercial vaccines or antiviral drugs are available for the prevention and treatment of weev infection in humans. in this paper, we constructed a recombinant weev vaccine, designated as ad5-weev, using a replication defective, human adenovirus serotype 5 (had5) as a delivery vector. ad5 ...200717467858
immunological evaluation of escherichia coli expressed e2 protein of western equine encephalitis virus.the western equine encephalitis virus (weev) is a potential biological warfare (bw) agent. the weev is endemic in western canada and has caused epidemics of "sleeping sickness" with a mortality rate of 7-9%. the e2 glycoprotein is a structural component of the weev and elicits production of neutralizing antibodies against the virus following an infection event. the envelope glycoprotein e2 is considered as the major target protein for the development of vaccines because it includes epitopes that ...200717499379
single-dose, fast-acting vaccine candidate against western equine encephalitis virus completely protects mice from intranasal challenge with different strains of the virus.western equine encephalitis virus (weev) causes a fatal infection of the central nervous system in humans and horses. however, neither human vaccine nor antiviral drug is available. we found previously that immunization of mice with two doses of an adenovirus-vectored weev vaccine, ad5-weev, confers complete protection against homologous weev challenge. in this paper, we report that a single-dose injection of ad5-weev completely protected mice against both homologous and heterologous strains of ...200717630056
comparison of immune responses of brown-headed cowbird and related blackbirds to west nile and other mosquito-borne encephalitis viruses.the rapid geographic spread of west nile virus (family flaviviridae, genus flavivirus, wnv) across the united states has stimulated interest in comparative host infection studies to delineate competent avian hosts critical for viral amplification. we compared the host competence of four taxonomically related blackbird species (icteridae) after experimental infection with wnv and with two endemic, mosquito-borne encephalitis viruses, western equine encephalomyelitis virus (family togaviridae, gen ...200717699082
differentiation of west nile and st. louis encephalitis virus infections by use of noninfectious virus-like particles with reduced cross-reactivity.differential diagnosis of st. louis encephalitis virus (slev) and west nile virus (wnv) infections can be complicated due to the high degree of cross-reactivity observed in most serodiagnostic assays. in an effort to provide a more specific diagnostic test, we developed virus-like particle (vlp) antigens with reduced cross-reactivity for both slev and wnv by identifying and mutating envelope protein amino acids within the cross-reactive epitopes of vlp expression plasmids. to determine the serod ...200717715375
nonspecific binding of complement by digestion fragments from antiviral gamma globulin.the nonspecificity of rabbit gamma-globulin (antibody) to western equine encephalitis virus and the non-specificity of normal rabbit gamma-globulin in complement-fixation tests with anti-gens prepared from chick-embryo cells infected with this virus and normal chick-embryo cells resided primarily in porter's fragment iii. addition of complement to fragment iii from the anti-body globulin, followed by inactivation of the added complement, abolished the complement-fixing ability of fragment iii wi ...196517737800
the antigenic stability of western equine encephalomyelitis virus. 193817738814
pre- and post-exposure protection against western equine encephalitis virus after single inoculation with adenovirus vector expressing interferon alpha.western equine encephalitis virus (weev) is a positive-sense, single-stranded rna virus which is transmitted to equines and humans through mosquito bites. weev infects the central nervous system with severe complications and even death. there are no human vaccine and antiviral drugs. we investigated whether adenovirus-mediated expression of interferon alpha could be used for pre- and post-exposure protection against a lethal weev challenge in mice. a human adenoviral vector (ad5-mifnalpha) expre ...200717761207
recovery of western equine encephalomyelitis virus from wild bird mites (liponyssus sylviarum) in kern county, california. 194717771930
experimental mixed infection of mice with lansing poliomyelitis virus and western equine encephalomyelitis virus. 194917838571
maturation-dependent responses of human neuronal cells to western equine encephalitis virus infection and type i interferons.innate cell-autonomous antiviral responses are essential first lines of defense against central nervous system infections but may also contribute to neuropathogenesis. we investigated the relationships between innate immunity and neuronal differentiation using an in vitro culture system with human cell lines to analyze cellular responses to the neurotropic alphavirus western equine encephalitis virus. human neuronal cells displayed a maturation-dependent reduction in virus-induced cytopathology ...200818022665
cloning, expression and purification of envelope proteins e1 and e2 of western equine encephalitis virus and potential use of them as antigens in immunoassays.the genes encoding envelope proteins e1 and e2 of western equine encephalitis virus (weev) were respectively cloned into a prokaryotic t7 rna polymerase-regulated expression vector. the recombinant c-terminal 6xhis-tagged weev e1 and e2 were expressed in bacteria as inclusion bodies that were subsequently solubilized with 8m urea, purified by immobilized metal ion affinity chromatography and finally refolded using an arginine system. the purified 6xhis-tagged proteins showed 50kda bands as revea ...200818054449
the influence of certain serum factors on the neutralization of western equine encephalomyelitis virus. 194918132345
limited interdecadal variation in mosquito (diptera: culicidae) and avian host competence for western equine encephalomyelitis virus (togaviridae: alphavirus).historically, western equine encephalomyelitis virus (weev) caused large equine and human epidemics in the americas from canada into argentina. despite recent enhanced surveillance for west nile virus, there have been few reports of equine or human cases and little documented enzootic activity of weev. during the past three years, weev has been active again in california, but without human or equine cases. in the current study, we compared host and vector competence of representative weev isolat ...200818385369
inhibition of alphavirus infection in cell culture and in mice with antisense morpholino oligomers.the genus alphavirus contains members that threaten human health, both as natural pathogens and as potential biological weapons. peptide-conjugated phosphorodiamidate morpholino oligomers (ppmo) enter cells readily and can inhibit viral replication through sequence-specific steric blockade of viral rna. sindbis virus (sinv) has low pathogenicity in humans and is regularly utilized as a model alphavirus. ppmo targeting the 5'-terminal and aug translation start site regions of the sinv genome bloc ...200818468653
a tetravalent dengue vaccine based on a complex adenovirus vector provides significant protection in rhesus monkeys against all four serotypes of dengue virus.nearly a third of the human population is at risk of infection with the four serotypes of dengue viruses, and it is estimated that more than 100 million infections occur each year. a licensed vaccine for dengue viruses has become a global health priority. a major challenge to developing a dengue vaccine is the necessity to produce fairly uniform protective immune responses to all four dengue virus serotypes. we have developed two bivalent dengue virus vaccines, using a complex adenovirus vector, ...200818480438
intensive early season adulticide applications decrease arbovirus transmission throughout the coachella valley, riverside county, california.in the coachella valley of california the seasonal onset of st. louis encephalitis virus (slev), western equine encephalomyelitis virus (weev), and west nile virus (wnv) has been detected consistently at the shoreline of the salton sea near the community of north shore. the timing and intensity of initial amplification in the culex tarsalis coquillett/wild bird cycle at this focus seemed closely linked to the subsequent dispersal of virus to the rest of the coachella valley and perhaps southern ...200818494603
arbovirus transmission by culex nigripalpus in florida, 2005.understanding the transmission patterns of west nile and st. louis encephalitis viruses (family flaviviridae, genus flavivirus, wnv and slev) could result in an increased ability to predict transmission risk to humans. to examine transmission patterns between vector and host, we trapped mosquitoes in three florida counties from june to november 2005 by using chicken-baited lard can mosquito traps. these traps were used to monitor for presence of wnv and slev in mosquitoes and subsequent transmis ...200818533444
persistent west nile virus transmission and the apparent displacement st. louis encephalitis virus in southeastern california, 2003-2006.west nile virus (family flaviviridae, genus flavivirus, wnv) invaded the colorado desert biome of southern california during summer 2003 and seemed to displace previously endemic st. louis encephalitis virus (family flaviviridae, genus flavivirus, slev, an antigenically similar flavivirus in the japanese encephalitis virus serocomplex). western equine encephalomyelitis virus (family togaviridae, genus alphavirus, weev), an antigenically distinct alphavirus, was detected during 2005 and 2006, ind ...200818533445
temperature, viral genetics, and the transmission of west nile virus by culex pipiens mosquitoes.the distribution and intensity of transmission of vector-borne pathogens can be strongly influenced by the competence of vectors. vector competence, in turn, can be influenced by temperature and viral genetics. west nile virus (wnv) was introduced into the united states of america in 1999 and subsequently spread throughout much of the americas. previously, we have shown that a novel genotype of wnv, wn02, first detected in 2001, spread across the us and was more efficient than the introduced gen ...200818584026
the dynamic envelope of a fusion class ii virus. e3 domain of glycoprotein e2 precursor in semliki forest virus provides a unique contact with the fusion protein e1.in alphaviruses, here represented by semliki forest virus, infection requires an acid-responsive spike configuration to facilitate membrane fusion. the creation of this relies on the chaperone function of glycoprotein e2 precursor (p62) and its maturation cleavage into the small external e3 and the membrane-anchored e2 glycoproteins. to reveal how the e3 domain of p62 exerts its control of spike functions, we determine the structure of a p62 cleavage-impaired mutant virus particle (sql) by elect ...200818596032
mass spectral data for 64 eluted peptides and structural modeling define peptide binding preferences for class i alleles in two chicken mhc-b haplotypes associated with opposite responses to marek's disease.in the chicken, resistance to lymphomas that form following infection with oncogenic strains of marek's herpesvirus is strongly linked to the major histocompatibility complex (mhc)-b complex. mhc-b21 haplotype is associated with lower tumor-related mortality compared to other haplotypes including mhc-b13. the single, dominantly expressed class i gene (bf2) is postulated as responsible for the mhc-b haplotype association. we used mass spectrometry to identify peptides and structural modeling to d ...200818612635
the effects of midgut serine proteases on dengue virus type 2 infectivity of aedes aegypti.dengue viruses (denv) cause significant morbidity and mortality worldwide and are transmitted by the mosquito aedes aegypti. mosquitoes become infected after ingesting a viremic bloodmeal, and molecular mechanisms involved in bloodmeal digestion may affect the ability of denv to infect the midgut. we used rna interference (rnai) to silence expression of four midgut serine proteases and assessed the effect of each rnai phenotype on denv-2 infectivity of aedes aegypti. silencing resulted in signif ...200818689635
development of human antibody fragments using antibody phage display for the detection and diagnosis of venezuelan equine encephalitis virus (veev).venezuelan equine encephalitis virus (veev) belongs to the alphavirus group. several species of this family are also pathogenic to humans and are recognized as potential agents of biological warfare and terrorism. the objective of this work was the generation of recombinant antibodies for the detection of veev after a potential bioterrorism assault or an natural outbreak of veev.200818764933
western equine encephalitis submergence: lack of evidence for a decline in virus virulence.the incidence of western equine encephalitis (wee) in humans and equids peaked during the mid-20th century and has declined to fewer than 1-2 human cases annually during the past 20 years. using the mouse model, changes in wee virus (weev) virulence were investigated as a potential explanation for the decline in the number of cases. evaluation of 10 weev strains representing a variety of isolation locations, hosts, and all decades from the 1940's to the 1990's yielded no evidence of a decline in ...200818801549
discovery of frameshifting in alphavirus 6k resolves a 20-year enigma.the genus alphavirus includes several potentially lethal human viruses. additionally, species such as sindbis virus and semliki forest virus are important vectors for gene therapy, vaccination and cancer research, and important models for virion assembly and structural analyses. the genome encodes nine known proteins, including the small '6k' protein. 6k appears to be involved in envelope protein processing, membrane permeabilization, virion assembly and virus budding. in protein gels, 6k migrat ...200818822126
functional pseudotyping of human immunodeficiency virus type 1 vectors by western equine encephalitis virus envelope glycoprotein.we investigated the ability of western equine encephalitis virus envelope glycoproteins (weev gp) to pseudotype lentiviral vectors. the titers of weev gp-pseudotyped human immunodeficiency virus type 1 (hiv) ranged as high as 8.0 x 10(4) iu/ml on permissive cells. sera from weev-infected mice specifically neutralized these pseudotypes; cell transduction was also sensitive to changes in ph. the host range of the pseudotyped particles in vitro was somewhat limited, which is atypical for most alpha ...200818842711
effects of inducing or inhibiting apoptosis on sindbis virus replication in mosquito cells.sindbis virus (sinv) is a mosquito-borne virus in the genus alphavirus, family togaviridae. like most alphaviruses, sinvs exhibit lytic infection (apoptosis) in many mammalian cell types, but are generally thought to cause persistent infection with only moderate cytopathic effects in mosquito cells. however, there have been several reports of apoptotic-like cell death in mosquitoes infected with alphaviruses or flaviviruses. given that apoptosis has been shown to be an antiviral response in othe ...200818931060
a versatile bifunctional dendritic cell targeting vaccine vector.we have developed an efficient versatile in vivo dendritic cell (dc) targeting vector for delivering different classes of antigens such as proteins, peptide, glycolipids and naked dna for vaccine applications. a single chain antibody (scfv) that recognizes dec-205 receptor of dc was fused with a core-streptavidin domain and expressed in escherichia coli using the t7 expression system. the bifunctional fusion protein (bffp) was expressed as a periplasmic soluble protein and affinity-purified in i ...200919053535
a single-amino acid substitution in west nile virus 2k peptide between ns4a and ns4b confers resistance to lycorine, a flavivirus inhibitor.lycorine potently inhibits flaviviruses in cell culture. at 1.2-microm concentration, lycorine reduced viral titers of west nile (wnv), dengue, and yellow fever viruses by 10(2)- to 10(4)-fold. however, the compound did not inhibit an alphavirus (western equine encephalitis virus) or a rhabdovirus (vesicular stomatitis virus), indicating a selective antiviral spectrum. the compound exerts its antiviral activity mainly through suppression of viral rna replication. a val-->met substitution at the ...200919062063
mode of transmission and the evolution of arbovirus virulence in mosquito vectors.the traditional assumption that vector-borne pathogens should evolve towards a benign relationship with their arthropod vectors has been challenged on theoretical grounds and empirical evidence. however, in the case of arboviruses (arthropod-borne viruses), although a number of investigators have reported experimental evidence for virus-induced vector mortality, others have failed to detect any significant impact. whether this variation in the observed level of arbovirus virulence depends on bio ...200919141420
repeated west nile virus epidemic transmission in kern county, california, 2004-2007.west nile virus (wnv) has remained epidemic in kern county, ca, since its introduction in 2004 through 2007 when the human case annual incidence increased from 6-8 to 17 per 100,000, respectively. the 2007 increase in human infection was associated with contradicting surveillance indicators, including severe drought, warm spring but cool summer temperature anomalies, decreased rural and urban mosquito abundance but increased early season infection in urban culex quinquefasciatus say, moderate av ...200919198528
identification of thieno[3,2-b]pyrrole derivatives as novel small molecule inhibitors of neurotropic alphaviruses.neurotropic alphaviruses such as western, eastern, and venezuelan equine encephalitis viruses cause serious and potentially fatal central nervous system infections in humans and are high-priority potential bioterrorism agents. there are currently no widely available vaccines or licensed therapies for these virulent pathogens. to identify potential novel antiviral drugs, we developed a cell-based assay with a western equine encephalitis virus replicon that expresses a luciferase reporter gene and ...200919239364
isolation of buggy creek virus (togaviridae: alphavirus) from field-collected eggs of oeciacus vicarius (hemiptera: cimicidae).alphaviruses (togaviridae) rarely have been found to be vertically transmitted from female arthropods to their progeny. we report two isolations of buggy creek virus (bcrv), an ecologically unusual alphavirus related to western equine encephalomyelitis virus, from field-collected eggs of cimicid swallow bugs (oeciacus vicarius horvath), the principal vector for bcrv. ten percent of egg pools were positive for bcrv, and we estimated minimum infection rates to be 1.03 infected eggs per 1,000 teste ...200919351091
virulence variation among isolates of western equine encephalitis virus in an outbred mouse model.little is known about viral determinants of virulence associated with western equine encephalitis virus (weev). here, we have analysed six north american weev isolates in an outbred cd1 mouse model. full genome sequence analyses showed < or =2.7 % divergence among the six weev isolates. however, the percentage mortality and mean time to death (mtd) varied significantly when mice received subcutaneous injections of 10(3) p.f.u. of each virus. two weev strains, mcmillan (mcm) and imperial 181 (imp ...200919403754
directed molecular evolution improves the immunogenicity and protective efficacy of a venezuelan equine encephalitis virus dna vaccine.we employed directed molecular evolution to improve the cross-reactivity and immunogenicity of the venezuelan equine encephalitis virus (veev) envelope glycoproteins. the dna encoding the e1 and e2 proteins from veev subtypes ia/b and ie, mucambo virus (mucv), and eastern and western equine encephalitis viruses (eeev and weev) were recombined in vitro to create libraries of chimeric genes expressing variant envelope proteins. elisas specific for all five parent viruses were used in high-throughp ...200919406186
comparative thermostability of west nile, st. louis encephalitis, and western equine encephalomyelitis viruses during heat inactivation for serologic diagnostics.during the monitoring of arbovirus seroprevalence in wild birds collected in california, we inadvertently made two isolates of western equine encephalomyelitis virus (weev) from california quail sera being tested by plaque reduction neutralization assay for antibodies against st louis encephalitis (slev) and west nile (wnv) viruses despite heating the sera at 56 degrees c for 30 minutes. these data prompted us to examine the thermostability of these viruses during heat treatment. the flaviviruse ...200919407138
effect of t-705 treatment on western equine encephalitis in a mouse model.a mouse model of western equine encephalitis (wee) was characterized for use in antiviral studies. virus was detected in several tissues, most notably an average titer of 9.5+/-1.1 log(10) 50% cell culture infectious doses (ccid(50))/g tissue in the brains of infected animals. signs of wee included limb weakness, paralysis, involuntary spasms or extension of limbs, clenching of paws, hunching, ruffling of fur, and eye exudates, many of which are indicative of neurological disease. the pyrazineca ...200919428608
chimeric alphavirus vaccine candidates protect mice from intranasal challenge with western equine encephalitis virus.we developed two types of chimeric sindbis virus (sinv)/western equine encephalitis virus (weev) alphaviruses to investigate their potential use as live virus vaccines against wee. the first-generation vaccine candidate, sin/co92, was derived from structural protein genes of weev strain co92-1356, and two second-generation candidates were derived from weev strain mcmillan. for both first- and second-generation vaccine candidates, the nonstructural protein genes were derived from sinv strain ar33 ...200919446595
cyclosporine inhibits flavivirus replication through blocking the interaction between host cyclophilins and viral ns5 protein.although flaviviruses cause significant human diseases, no effective therapy is currently available. host factors essential for viral replication are potential targets for antiviral development. here we report that cyclophilins (cyps), a family of cellular peptidyl-prolyl isomerases (ppiases), play a role in flavivirus replication. huh-7.5 cells with knockdown of different isoforms of cyp were less efficient than parental cells in supporting flavivirus replication, including west nile virus (wnv ...200919451286
surveillance of mosquito-borne viruses in alberta using reverse transcription polymerase chain reaction with generic primers.mosquitoes collected during 2003, 2004, and 2005 in alberta, canada, were screened for the presence of a wide range of arboviruses by reverse transcription-polymerase chain reaction (rt-pcr). nucleic acid extracts from mosquito slurries were amplified using universal primers designed to detect viruses belonging to the flavivirus genus of the flaviviridae family and california and bunyamwera serogroups of the bunyavirus genus within the bunyaviridae family. species-specific detection of western e ...200919496438
immune interference after sequential alphavirus vaccine vaccinations.we compared the effect of order of administration of investigational alphavirus vaccines on neutralizing antibody response. volunteers who received the inactivated eastern and western equine encephalitis (eee and wee) vaccines before live attenuated venezuelan (vee) vaccine had significantly lower rates of antibody response than those receiving vee vaccine before eee and wee vaccines (66.7% vs. 80.6%; p=0.026). the odds of having a vee antibody non-response among those initially receiving eee an ...200919576665
performance of the realstar chikungunya virus real-time reverse transcription-pcr kit.a novel commercial chikungunya virus real-time reverse transcription-pcr (rt-pcr) kit was evaluated on a comprehensive panel of original patient samples. the assay was 100% sensitive and specific in comparison to a published real-time rt-pcr. viral loads from both assays were highly correlated. the kit proved to be suitable for routine use in patient care.200919625474
environmental and biological factors influencing culex pipiens quinquefasciatus say (diptera: culicidae) vector competence for saint louis encephalitis virus.complex interactions between environmental and biological factors influence the susceptibility of culex pipiens quinquefasciatus to st. louis encephalitis virus and could affect the epidemiology of virus transmission. similar interactions could have epidemiologic implications for other vector-virus systems. we conducted an experiment to examine four such factors in combination: mosquito age, extrinsic incubation temperature (eit), virus dose, and colony. the proportion of mosquitoes with body in ...200919635881
similarities and differences in antagonism of neuron alpha/beta interferon responses by venezuelan equine encephalitis and sindbis alphaviruses.venezuelan equine encephalitis virus (veev) is highly virulent in adult laboratory mice, while sindbis virus (sinv) is avirulent regardless of dose or inoculation route, dependent upon functioning alpha/beta interferon (ifn-alpha/beta) responses. we have examined each virus' resistance to and/or antagonism of ifn-alpha/beta responses in neurons, a cell type targeted by both viruses in mice, by infecting ifn-alpha/beta-treated or untreated primary cultures with viruses or virus-derived replicons ...200919641001
genomic sequencing of highlands j virus: a comparison to western and eastern equine encephalitis viruses.highlands j virus (hjv) is a member of the genus alphavirus, family togaviridae. hjv is the sole representative of the western equine encephalitis (wee) serocomplex found in the eastern united states, and circulates in nature in an apparently identical transmission cycle as eastern equine encephalitis virus (eeev). north american representatives of the wee serocomplex [hjv, wee virus (weev), and fort morgan virus (fmv)] are believed to be derived from a recombination event involving eeev and a s ...200919651164
emerging viral infections of the central nervous system: part 1.in this 2-part review, i will focus on emerging virus infections of the central nervous system (cns). part 1 will introduce the basic features of emerging infections, including their definition, epidemiology, and the frequency of cns involvement. important mechanisms of emergence will be reviewed, including viruses spreading into new host ranges as exemplified by west nile virus (wnv), japanese encephalitis (je) virus, toscana virus, and enterovirus 71 (ev71). emerging infections also result fro ...200919667214
exclusion of west nile virus superinfection through rna replication.superinfection exclusion is the ability of an established viral infection to interfere with a second viral infection. using west nile virus (wnv) as a model, we show that replicating replicons in bhk-21 cells suppress subsequent wnv infection. the wnv replicon also suppresses superinfections of other flaviviruses but not nonflaviviruses. mode-of-action analysis indicates that the exclusion of wnv superinfection occurs at the step of rna synthesis. the continuous culturing of wnv in the replicon- ...200919726510
replication cycle of chikungunya: a re-emerging arbovirus.arboviruses (or arthropod-borne viruses), represent a threat for the new century. the 2005-2006 year unprecedented epidemics of chikungunya virus (chikv) in the french reunion island in the indian ocean, followed by several outbreaks in other parts of the world such as india, have attracted the attention of clinicians, scientists, and state authorities about the risks linked to this re-emerging mosquito-borne virus. chikv, which belongs to the alphaviruses genus, was not previously regarded as a ...200919732931
aedes triseriatus females transovarially infected with la crosse virus mate more efficiently than uninfected mosquitoes.the mating efficiencies (the percentage of females inseminated by males) of field-collected and laboratory-colonized aedes triseriatus (say) (diptera: culicidae) female mosquitoes transovarially infected or uninfected with la crosse virus (lacv) were compared. the females were placed in cages with age-matched males, and the insemination rates (number of inseminated females of the total number of females examined) were determined daily by detection of sperm in the spermathecae. lacv-infected mosq ...200919769048
stone lakes virus (family togaviridae, genus alphavirus), a variant of fort morgan virus isolated from swallow bugs (hemiptera: cimicidae) west of the continental divide.multiple isolates of an alphaviruses within the western equine encephalomyelitis-serocomplex that were related closely to ft. morgan and its variant buggy creek virus were made from swallow bugs, oeciacus vicarius horvath (hemiptera: cimicidae), collected from cliff swallow (petrochelidon pyrrhonota) nests at the stone lakes national wildlife refuge, sacramento county, ca, during the summers of 2005 and 2006. this virus (hereafter stone lakes virus, family togaviridae, genus alphavirus, stlv) wa ...200919769055
encephalitic alphaviruses.this review will cover zoonotic, encephalitic alphaviruses in the family togaviridae. encephalitic alphaviruses, i.e. western- (weev), eastern- (eeev), venezuelan equine encephalitis virus (veev) and, more rarely, ross river virus, chikungunya virus and highlands j virus (hjv), are neuroinvasive and may cause neurological symptoms ranging from mild (e.g., febrile illness) to severe (e.g., encephalitis) in humans and equines. among the naturally occurring alphaviruses, weev, eeev and veev have wi ...201019775836
vaccines for venezuelan equine encephalitis.arboviruses are capable of causing encephalitis in animals and human population when transmitted by the vector or potentially via infectious aerosol. recent re-emergence of venezuelan equine encephalitis virus (veev) in south america emphasizes the importance of this pathogen to public health and veterinary medicine. despite its importance no antivirals or vaccines against veev are currently available in the usa. here we review some of the older and newer approaches aimed at generating a safe an ...200919837294
a trans-complementing recombination trap demonstrates a low propensity of flaviviruses for intermolecular recombination.intermolecular recombination between the genomes of closely related rna viruses can result in the emergence of novel strains with altered pathogenic potential and antigenicity. although recombination between flavivirus genomes has never been demonstrated experimentally, the potential risk of generating undesirable recombinants has nevertheless been a matter of concern and controversy with respect to the development of live flavivirus vaccines. as an experimental system for investigating the abil ...201019864381
active immunication of guinea pigs with the virus of equine encephalomyelitis : i. quantitative experiments with various preparations of active virus.active eastern or western equine encephalomyelitis virus in three forms,-chemically untreated but simply passaged through series of mice; adsorbed on alumina gel c, and precipitated by tannin,-yielded practically the same results when employed for the immunization of guinea pigs. the virus is not inactivated by the process of adsorption or precipitation : guinea pigs and mice inoculated in the brain with these materials develop lethal encephalomyelitis in the same manner as when chemically untre ...193619870474
an acquired resistance of growing animals to certain neurotropic viruses in the absence of humoral antibodies or previous exposure to infection.1. as mice grow older they acquire a resistance to peripheral inoculation with the indiana and new jersey strains of vesicular stomatitis virus and to some extent also to western equine encephalomyelitis virus, but little or none to the eastern strain. 2. while some mice may become resistant as early as the 30th day of life, others may still be susceptible at 1 year of age. 3. this resistance is readily demonstrable when the inoculations are made by intranasal, subcutaneous, intramuscular, intra ...193619870564
laboratory transmission of western equine encephalomyelitis virus by mosquitoes of the genera culex and culiseta.1. western equine virus has been successfully transmitted in the laboratory by 3 species of mosquitoes from 2 genera not previously reported as laboratory vectors: culex tarsalis, culiseta inornata, and culiseta incidens. 2. though transmission was not demonstrated, survival of the virus for more than a few days was shown to occur in culex stigmatosoma and psorophora confinnis. possibly transmission occurred by the former. 3. in experiments with culex tarsalis, infection of the mosquitoes occurr ...194319871339
induced resistance of the central nervous system to experimental infection with equine encephalomyelitis virus : iii. abortive infection with western virus and subsequent interference with the action of heterologous viruses.although vaccination of guinea pigs with formalin-inactivated western equine encephalomyelitis virus rendered them specifically immune to an intracerebral challenge dose of 1,000 m.l.d. of western virus, it failed to protect their central nervous system against the initial effects of the virus: the intracerebral challenge dose was followed by an abortive infection of 20 to 30 hours' duration characterized by fever and histopathological changes which simulated the response at that early stage of ...194419871408
western equine encephalomyelitis virus in the blood of experimentally inoculated chickens.1. chickens inoculated subcutaneously with 0.2 cc. of a 10(-2) to 10(-7) dilution of western equine mouse brain virus had the virus in the blood serum between the 12th and the 48th hour in most instances. the fowls showed no signs of illness. 2. viremia could be induced regularly in chickens by inoculating subcutaneously the least amount of virus which would produce encephalitis in the mouse when inoculated by the intracerebral route. 3. even the minimal infecting dose for a chicken led to such ...194619871522
a multisystem approach for development and evaluation of inactivated vaccines for venezuelan equine encephalitis virus (veev).a multisystem approach was used to assess the efficiency of several methods for inactivation of venezuelan equine encephalitis virus (veev) vaccine candidates. a combination of diverse assays (plaque, in vitro cytopathology and mouse neurovirulence) was used to verify virus inactivation, along with the use of a specific elisa to measure retention of veev envelope glycoprotein epitopes in the development of several inactivated veev candidate vaccines derived from an attenuated strain of veev (v35 ...201019903494
an adenosine nucleoside inhibitor of dengue virus.dengue virus (denv), a mosquito-borne flavivirus, is a major public health threat. the virus poses risk to 2.5 billion people worldwide and causes 50 to 100 million human infections each year. neither a vaccine nor an antiviral therapy is currently available for prevention and treatment of denv infection. here, we report a previously undescribed adenosine analog, nitd008, that potently inhibits denv both in vitro and in vivo. in addition to the 4 serotypes of denv, nitd008 inhibits other flavivi ...200919918064
identification of western equine encephalitis virus structural proteins that confer protection after dna vaccination.dna vaccines encoding different portions of the structural proteins of western equine encephalitis virus were tested for the efficacy of their protection in a 100% lethal mouse model of the virus. the 6k-e1 structural protein encoded by the dna vaccine conferred complete protection against challenge with the homologous strain and limited protection against challenge with a heterologous strain.201019923571
alphavirus antiviral drug development: scientific gap analysis and prospective research areas.the new world alphaviruses venezuelan equine encephalitis virus (veev), eastern equine encephalitis virus (eeev), and western equine encephalitis virus (weev) pose a significant threat to human health as the etiological agents of serious viral encephalitis through natural infection as well as through their potential use as a biological weapon. at present, there is no fda-approved medical treatment for infection with these viruses. the defense threat reduction agency, joint science and technology ...200920028250
recovery from viral encephalomyelitis: immune-mediated noncytolytic virus clearance from neurons.viral encephalomyelitis is caused by virus infections of neurons in the brain and spinal cord. recovery is dependent on immune-mediated control and clearance of virus from these terminally differentiated essential cells. preservation of neuronal function is essential for prevention of neurologic sequelae such as paralysis, seizures and cognitive deficits. using the model system of sindbis virus-induced encephalomyelitis in mice, we have shown that immune-mediated clearance of infectious virus fr ...201020087684
pathology and virus detection in tissues of nestling house sparrows naturally infected with buggy creek virus (togaviridae).alphaviruses (togaviridae) infect wild birds, but clinical illness and death attributable to virus in naturally infected birds is rarely reported, particularly for small passerine species or nestlings. buggy creek virus is a unique alphavirus in the western equine encephalomyelitis virus (weev) complex that is vectored by the cimicid swallow bug (oeciacus vicarius), an ectoparasite of the colonially nesting cliff swallow (petrochelidon pyrrhonota) and the introduced house sparrow (passer domesti ...201020090015
transmission potential of two chimeric western equine encephalitis vaccine candidates in culex tarsalis.western equine encephalitis virus (weev) is a zoonotic alphavirus that circulates in western north america between passerine birds and mosquitoes, primarily culex tarsalis. since it was isolated in 1930, weev has caused tens of thousands of equine deaths in addition to thousands of human cases. in addition because weev is a virus of agricultural importance in addition to a public health threat, we developed two live-attenuated chimeric vaccine candidates that have been shown to be immunogenic an ...201020134017
mechanisms of viral emergence.a number of virologic and environmental factors are involved in the emergence and re-emergence of viral disease. viruses do not conservatively occupy a single and permanent ecological niche. rather, due to their intrinsic capacity for genetic change, and to the evolvability of fitness levels, viruses display a potential to parasitize alternative host species. mutation, recombination and genome segment reassortment, and combination of these molecular events, produce complex and phenotypically div ...201020167200
the neutralization of western equine encephalomyelitis virus by human convalescent serum; the influence of heat labile substances in serum on the neutralization index. 194720240799
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