| genotype iii saint louis encephalitis virus outbreak, argentina, 2005. | twenty-six years after it was last detected, saint louis encephalitis virus (slev) genotype iii reemerged in 2005 in c6rdoba, argentina, where it caused an outbreak. two genotype iii slev strains were isolated from culex quinquefasciatus. a 71.43% prevalence for neutralizing antibodies was found in domestic fowl in the homestead of a patient with encephalitis. | 2006 | 17283629 |
| chronic st. louis encephalitis virus infection in the golden hamster (mesocricetus auratus). | to further study the phenomenon of flavivirus persistent infection, golden hamsters (mesocricetus auratus) were inoculated intraperitoneally with a low pathogenicity strain of st. louis encephalitis virus (slev). after inoculation, the animals remained asymptomatic and developed high levels of specific neutralizing antibodies in their sera. however, about one half of the hamsters continued to shed infectious slev in their urine for prolonged periods of time. by co-cultivation, slev was recovered ... | 2007 | 17297039 |
| 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 ... | 2006 | 17304934 |
| 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 ... | 2006 | 17326938 |
| west nile virus antibody prevalence in wild mammals, southern wisconsin. | twenty percent prevalence of west nile virus antibody was found in free-ranging medium-sized wisconsin mammals. no significant differences were noted in antibody prevalence with regard to sex, age, month of collection, or species. our results suggest a similar route of infection in these mammals. | 2006 | 17326959 |
| association of west nile virus illness and urban landscapes in chicago and detroit. | west nile virus infection in humans in urban areas of the midwestern united states has exhibited strong spatial clustering during epidemic years. we derived urban landscape classes from the physical and socio-economic factors hypothesized to be associated with west nile virus (wnv) transmission and compared those to human cases of illness in 2002 in chicago and detroit. the objectives were to improve understanding of human exposure to virus-infected mosquitoes in the urban context, and to assess ... | 2007 | 17352825 |
| panmicrobial oligonucleotide array for diagnosis of infectious diseases. | to facilitate rapid, unbiased, differential diagnosis of infectious diseases, we designed greenechippm, a panmicrobial microarray comprising 29,455 sixty-mer oligonucleotide probes for vertebrate viruses, bacteria, fungi, and parasites. methods for nucleic acid preparation, random primed pcr amplification, and labeling were optimized to allow the sensitivity required for application with nucleic acid extracted from clinical materials and cultured isolates. analysis of nasopharyngeal aspirates, b ... | 2007 | 17370518 |
| alkhurma hemorrhagic fever virus in ornithodoros savignyi ticks. | evidence for the tickborne nature of alkhurma hemorrhagic fever virus (ahfv) is indirect because ahfv has not been detected in arthropods. one ornithodoros savignyi tick from saudi arabia contained ahfv rna. this is the first direct evidence that ahfv is a tickborne flavivirus and confirms the association between human ahfv cases and tickbite history. | 2007 | 17370534 |
| saint louis encephalitis virus, brazil. | | 2007 | 17370543 |
| identification of dengue virus in respiratory specimens from a patient who had recently traveled from a region where dengue virus infection is endemic. | dengue is the most important arthropod-borne viral disease, and it is a major public health problem in subtropical and tropical regions. the virus is transmitted to humans by the bite of infected female mosquitoes of the genus aedes. the global resurgence of dengue is thought to be due to failure to control the aedes populations, uncontrolled urbanization, population growth, climate change, and increased airplane travel. in this paper we describe the methods used to detect dengue virus infection ... | 2007 | 17376878 |
| surveillance for west nile virus in clinic-admitted raptors, colorado. | in 2005, 13.5% of clinic-admitted raptors in northern colorado tested positive for west nile virus (wnv). clinic-admitted-raptor surveillance detected wnv activity nearly 14 weeks earlier than other surveillance systems. wnv surveillance using live raptor admissions to rehabilitation clinics may offer a novel surveillance method and should be considered along with other techniques already in use. | 2007 | 17479898 |
| mosquitoborne infections after hurricane jeanne, haiti, 2004. | after hurricane jeanne in september 2004, surveillance for mosquitoborne diseases in gonaïves, haiti, identified 3 patients with malaria, 2 with acute dengue infections, and 2 with acute west nile virus infections among 116 febrile patients. these are the first reported human west nile virus infections on the island of hispaniola. | 2007 | 17479899 |
| in vitro resistance selection and in vivo efficacy of morpholino oligomers against west nile virus. | we characterize in vitro resistance to and demonstrate the in vivo efficacy of two antisense phosphorodiamidate morpholino oligomers (pmos) against west nile virus (wnv). both pmos were conjugated with an arg-rich peptide. one peptide-conjugated pmo (ppmo) binds to the 5' terminus of the viral genome (5'-end ppmo); the other targets an essential 3' rna element required for genome cyclization (3' conserved sequence i [3' csi] ppmo). the 3' csi ppmo displayed a broad spectrum of antiflavivirus act ... | 2007 | 17485503 |
| depression after infection with west nile virus. | previous reports have noted depression after west nile virus (wnv) infection. we further measured this outcome and found that 31% of patients reported new-onset depression and 75% of these had center for epidemiologic studies depression scores indicative of mild-to-severe depression. physicians should be aware of neuropsychiatric consequences of wnv in patients. | 2007 | 17552106 |
| west nile virus, venezuela. | | 2007 | 17561567 |
| a multiplexed taqman assay for the detection of arthropod-borne flaviviruses. | arboviruses in the genus flavivirus are major causes of human disease worldwide, and yet they are widely under reported. this is partially due to the classical methods of detection, using virologic or immunologic techniques, which typically lack sensitivity and specificity or require biological containment facilities in order to manipulate infectious cultures. molecular detection assays based on broadly reactive (degenerate) primers also tend to have differential and lower sensitivity for many f ... | 2007 | 17583360 |
| epitope-blocking enzyme-linked immunosorbent assay to differentiate west nile virus from japanese encephalitis virus infections in equine sera. | west nile virus (wnv) is now widely distributed worldwide, except in most areas of asia where japanese encephalitis virus (jev) is distributed. considering the movement and migration of reservoir birds, there is concern that wnv may be introduced in asian countries. although manuals and guidelines for serological tests have been created in japan in preparedness for the introduction of wnv, differential diagnosis between wnv and jev may be complicated by antigenic cross-reactivities between these ... | 2007 | 17596430 |
| validation of a microsphere-based immunoassay for detection of anti-west nile virus and anti-st. louis encephalitis virus immunoglobulin m antibodies. | a microsphere-based immunoassay (mia) was previously developed that is capable of determining the presence of anti-west nile (wn) virus or anti-st. louis encephalitis (sle) virus immunoglobulin m (igm) antibodies in human serum or cerebrospinal fluid. the original data set on which the classification rules were based comprised 491 serum specimens obtained from the serum bank at the division of vector-borne infectious diseases of the centers for disease control and prevention (dvbid). the classif ... | 2007 | 17609393 |
| a real-time taqman polymerase chain reaction for the identification of culex vectors of west nile and saint louis encephalitis viruses in north america. | in north america, west nile and st. louis encephalitis viruses have been detected in a wide range of vector species, but the majority of isolations continue to be from pools of mixed mosquitoes in the culex subgenus culex. unfortunately, the morphologic identification of these important disease vectors is often difficult, particularly in regions of sympatry. we developed a sensitive real-time taqman polymerase chain reaction assay that allows reliable identification of culex mosquitoes including ... | 2007 | 17620631 |
| flavivirus serology by western blot analysis. | the spread of west nile virus (wnv) across the united states into areas with endemic flavivirus activity has complicated serologic surveillance of seasonal virus activity and diagnosis of infected individuals. here we describe preliminary results from a comparison of serologic assays for flaviviruses: the reference plaque reduction neutralization test (prnt), enzyme immunoassay (eia), and a western blot (wb) in which crude viral lysates were electrophoresed and blotted onto nitrocellulose. human ... | 2007 | 17620648 |
| experimental transmission of west nile virus by culex nigripalpus from honduras. | as a result of concerns regarding the geographic spread of west nile virus (wnv) to central america, we evaluated the potential for honduran culex nigripalpus theobald to transmit this virus. we tested individual mosquitoes captured in olancho province, honduras, in september 2003. mosquitoes were allowed to feed on 2- to 4- day-old chickens previously inoculated with a new york strain (crow 397-99) of wnv. infection rates in cx. nigripalpus ranged from 81%-96% after feeding on chickens with vir ... | 2007 | 17627449 |
| western equine encephalitis in saskatchewan reptiles and amphibians, 1961-1963. | western equine encephalitis (wee) antibodies were found in blood samples from garter snakes and leopard frogs collected in saskatchewan but wee virus was not recovered from any of the specimens. evidence of natural wee infection in snakes was found in 8 different localities while in frogs in two only. experimentally, garter snakes were readily infected and developed a high, relatively sustained viremia without signs of disease. after experimental exposure, viremia persisted regularly for 10 to 1 ... | 1964 | 17649511 |
| simultaneous infection by denv-3 and slev in brazil. | | 2007 | 17658293 |
| reduced infection in mosquitoes exposed to blood meals containing previously frozen flaviviruses. | the increased difficulty and expense of using live animals for delivering infectious blood meals in arthropod-borne virus vector competence experiments has resulted in an increase in the use of artificial feeding systems. compared to live hosts, artificial systems require higher viral titers to attain mosquito infection, thereby limiting the utility of such systems with low or moderate titer virus stocks. based on the report that freshly propagated virus is more infectious than previously frozen ... | 2007 | 17686541 |
| adaptation of two flaviviruses results in differences in genetic heterogeneity and virus adaptability. | west nile virus (wnv) is a mosquito-borne flavivirus that was first introduced into the usa in the new york city area in 1999. since its introduction, wnv has steadily increased both its host and geographical ranges. outbreaks of the closely related flavivirus, st. louis encephalitis virus (slev), occur in the usa periodically, but levels of activity and host range are more restricted than those of wnv. understanding the selective pressures that drive arbovirus adaptation and evolution in their ... | 2007 | 17698648 |
| 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 ... | 2007 | 17699082 |
| 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 ... | 2007 | 17715375 |
| interference between st. louis encephalitis virus and equine encephalomyelitis virus (western type) in the chick embryo. | interference between two unrelated viruses is reported. equine encephalomyelitis virus grows only to a limited degree, if at all, when injected into chick embryos in which st. louis encephalitis virus is being propagated. | 1944 | 17815105 |
| isolation of st. louis encephalitis virus from bats (tadarida b. mexicana) in texas. | a strain of st. louis encephalitis virus has been isolated from mexican free-tailed bats (tadarida b. mexicana) collected at the time of an outbreak of encephalitis in texas in 1964. | 1966 | 12325353 |
| temporal and geographic genetic variation in culex nigripalpus theobald (culicidae: diptera), a vector of st. louis encephalitis virus, from florida. | a field population of culex (culex) nigripalpus theobald from vero beach, fl sampled monthly over a period of 24 mo, a colony sample and 10 geographic samples were analyzed for genetic variation at 14 enzyme loci using polyacrylamide gel electrophoresis. the cx. nigripalpus colony sample showed significantly lower genetic variation than the field-collected samples, measured by mean number of alleles per locus (colony 1.4 +/- 0.1 versus field 2.1 +/- 0.22), percentage of polymorphic loci (colony ... | 2002 | 12495183 |
| st. louis encephalitis outbreak in louisiana in 2001. | a description of the st. louis encephalitis (sle) outbreak in northeast louisiana is presented. in the fall of 2001 there were 63 cases of st. louis encephalitis in monroe and west monroe and seven additional cases in the neighboring parishes of richland, morehouse and franklin. all cases had a clinical presentation of encephalitis and were confirmed serologically. clinically most cases presented with fever, meningitis syndrome with altered mental status. tremors were common (56% of cases). ther ... | 2002 | 12517026 |
| application of modified shell vial culture procedure for arbovirus detection. | the isolation of arboviruses from patient's low titer sera can be difficult. here we compared the detection efficiency of dengue (den), yellow fever (yf), saint louis encephalitis (sle), west nile (wn), ilheus (ilh), group c (gc), oropouche (oro), mayaro (may) and venezuela encephalitis equine (vee) viruses using a modified shell vial culture (msvc) protocol to a standard cell culture (scc) protocol. first the msvc and scc protocols were compared using five dilutions for each of the following st ... | 2007 | 17940598 |
| mosquitoes inoculate high doses of west nile virus as they probe and feed on live hosts. | west nile virus (wnv) is transmitted to vertebrate hosts by mosquitoes as they take a blood meal. the amount of wnv inoculated by mosquitoes as they feed on a live host is not known. previous estimates of the amount of wnv inoculated by mosquitoes (10(1.2)-10(4.3) pfu) were based on in vitro assays that do not allow mosquitoes to probe or feed naturally. here, we developed an in vivo assay to determine the amount of wnv inoculated by mosquitoes as they probe and feed on peripheral tissues of a m ... | 2007 | 17941708 |
| detection and typing of human herpesvirus 6 by molecular methods in specimens from patients diagnosed with encephalitis or meningitis. | human herpesvirus 6 (hhv-6) was detected in specimens from patients hospitalized with symptoms of encephalitis or meningitis. a real-time pcr assay was developed which has a linear dynamic range of 5 to 5 x 10(6) copies of hhv-6 and a sensitivity of five gene copies per reaction. while the assay detects both subtypes, hhv-6a and hhv-6b, it is specific and does not cross-react with a selected specificity panel. a total of 1,482 patient specimens, which were collected between 2003 and 2007, were t ... | 2007 | 17942643 |
| effect of hurricane katrina on arboviral disease transmission. | | 2007 | 17953117 |
| the extent of homologous recombination in members of the genus flavivirus. | the family flaviviridae includes important human pathogens, such as dengue (den) virus, yellow fever (yf) virus and hepatitis c virus, many of which have emerged or re-emerged in recent years. until recently, flavivirus evolution was thought to proceed in a clonal manner, with diversity generated mainly through the accumulation of mutational changes. however, this assumption has now been shown to be invalid, with homologous recombination demonstrated in all three genera of the flaviviridae: sinc ... | 2003 | 12560576 |
| evaluation of an indirect immunofluorescence assay for detection of immunoglobulin m (igm) and igg antibodies against yellow fever virus. | the first commercial indirect immunofluorescence assay (ifa) using euroimmun biochip technology was evaluated for the serodiagnosis of immunoglobulin g (igg) and igm antibodies against yellow fever virus (yfv) and was compared with the plaque reduction neutralization test (prnt), which is currently the gold standard test for yfv. an overall correlation between the tests of 98.7% was established based on the analysis of 150 sera from individuals after vaccination with the 17d yellow fever vaccine ... | 2008 | 18045884 |
| defining the levels of secreted non-structural protein ns1 after west nile virus infection in cell culture and mice. | infection with west nile virus (wnv) causes a febrile illness that can progress to meningitis or encephalitis, primarily in humans that are immunocompromised or elderly. for successful treatment of wnv infection, accurate and timely diagnosis is essential. previous studies have suggested that the flavivirus non-structural protein ns1, a highly conserved and secreted glycoprotein, is a candidate protein for rapid diagnosis. herein, we developed a capture enzyme-linked immunosorbent assay (elisa) ... | 2008 | 18205232 |
| evaluation of the langat/dengue 4 chimeric virus as a live attenuated tick-borne encephalitis vaccine for safety and immunogenicity in healthy adult volunteers. | with the steady rise in tick-borne encephalitis virus (tbev) infections in europe, development of a live attenuated vaccine that will generate long-lasting immunity would be of considerable benefit. a chimeric flavivirus, designated lgt/den4, was previously constructed to have a genome containing the prm and e protein genes of langat virus (lgt), a naturally attenuated member of the tbev complex, and the remaining genetic sequences derived from dengue 4 virus (den4). lgt/den4 was highly attenuat ... | 2008 | 18207289 |
| reliable detection of st. louis encephalitis virus by rt-nested pcr. | st. louis encephalitis virus (slev) is a re-emerging arbovirus in south america, with reported cases in humans in argentina and brazil. this fact indicates that there is an urgent need to increase the current knowledge about this virus in order to control and prevent future cases. exhaustive epidemiological and laboratory investigation is required to ensure fast, accurate identification of the viral agent and allow prompt surveillance action by health authorities. herein, we report the developme ... | 2008 | 18208760 |
| human outbreak of st. louis encephalitis detected in argentina, 2005. | an outbreak of flavivirus encephalitis occurred in 2005 in córdoba province, argentina. | 2008 | 18249032 |
| serologic diagnosis of west nile and st. louis encephalitis virus infections in domestic chickens. | adult domestic chickens were infected with west nile virus (wnv) or st. louis encephalitis virus (slev) and challenged with homologous or heterologous virus at 21 or 56 days postinfection (dpi). sera were collected at selected time points after infection and assayed by enzyme immunoassay (eia), plaque reduction neutralization test (prnt), and a western blot (wb) alternative to prnt. eia results were sensitive and accurate (few false positives) but not specific, requiring a confirmatory test to d ... | 2008 | 18337340 |
| antibody and interleukin-12 treatment in murine models of encephalitogenic flavivirus (st. louis encephalitis, tick-borne encephalitis) and alphavirus (venezuelan equine encephalitis) infection. | early and sustained treatment with interleukin-12 (il-12) ameliorated disease in a mouse model of infection with the encephalitogenic flavivirus, st. louis encephalitis virus (slev, japanese encephalitis serogroup). however, this effect was not reproduced in murine infections with either the flavivirus tick-bore encephalitis virus (tbev) or the alphavirus venezuelan equine encephalitis virus (veev). il-12 exacerbated tbev disease when used in conjunction with monoclonal antibody (mab), suggestin ... | 2003 | 12639298 |
| eared dove (zenaida auriculata, columbidae) as host for st. louis encephalitis virus (flaviviridae, flavivirus). | st. louis encephalitis virus (slev) is an emerging flavivirus in south american countries. its ecology and biological transmission cycles are scarcely known. eared doves (zenaida auriculata) have frequently been found infected by slev, and therefore, could be suspected as slev hosts. thirty post-hatch-year eared doves were subcutaneously inoculated with the genotype v slev 78v-6507 viral strain and subsequently bled. no deaths or clinical signs of illness were observed in the inoculated doves. t ... | 2008 | 18429694 |
| maturation of west nile virus modulates sensitivity to antibody-mediated neutralization. | west nile virions incorporate 180 envelope (e) proteins that orchestrate the process of virus entry and are the primary target of neutralizing antibodies. the e proteins of newly synthesized west nile virus (wnv) are organized into trimeric spikes composed of pre-membrane (prm) and e protein heterodimers. during egress, immature virions undergo a protease-mediated cleavage of prm that results in a reorganization of e protein into the pseudo-icosahedral arrangement characteristic of mature virion ... | 2008 | 18464894 |
| molecular mechanisms of antibody-mediated neutralisation of flavivirus infection. | flaviviruses are a group of positive-stranded rna viruses that cause a spectrum of severe illnesses globally in more than 50 million individuals each year. while effective vaccines exist for three members of this group (yellow fever, japanese encephalitis, and tick-borne encephalitis viruses), safe and effective vaccines for several other flaviviruses of clinical importance, including west nile and dengue viruses, remain in development. an effective humoral immune response is critical for protec ... | 2008 | 18471342 |
| previous infection protects house finches from re-infection with st. louis encephalitis virus. | antibody titers against st. louis encephalitis virus (sle) measured by a plaque reduction neutralization test (prnt) decreased rapidly in house finches (capodacus mexicanus) after initial infection, whereas antibodies measured by enzyme immunoassay (eia) remained detectable in all birds for the length of the experiment, indicating long-term persistence and greater assay sensitivity of the eia. after 52 wk, birds were challenged by subcutaneous inoculation with the same strain of sle virus. virus ... | 2003 | 12943108 |
| 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 ... | 2008 | 18494603 |
| using hydrologic conditions to forecast the risk of focal and epidemic arboviral transmission in peninsular florida. | the accurate forecasting and tracking of arboviral transmission is becoming increasingly critical for the early recognition and management of arboviral epidemics. meteorological factors, especially rainfall and temperature, drive arboviral epidemics, but monitoring rainfall and temperature alone is not predictive of increased levels of vector-borne disease transmission. in florida, model simulations of water table depth (wtd) provide a measure of drought, and they have been shown to provide an a ... | 2008 | 18533440 |
| 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 ... | 2008 | 18533444 |
| 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 ... | 2008 | 18533445 |
| characterization of mosquito-adapted west nile virus. | west nile virus (wnv), a mosquito-borne flavivirus, has significantly expanded its geographical and host range since its 1999 introduction into north america. the underlying mechanisms of evolution of wnv and other arboviruses are still poorly understood. studies evaluating virus adaptation and fitness in relevant in vivo systems are largely lacking. in order to evaluate the capacity for host-specific adaptation and the genetic correlates of adaptation in vivo, this study measured phenotypic and ... | 2008 | 18559933 |
| closing the door on flaviviruses: entry as a target for antiviral drug design. | with the emergence and rapid spread of west nile virus in the united states since 1999, and the 50-100 million infections per year caused by dengue virus globally, the threat of flaviviruses as re-emerging human pathogens has become a reality. to support the efforts that are currently being pursued to develop effective vaccines against these viruses, researchers are also actively pursuing the development of small molecule compounds that target various aspects of the virus life cycle. recent adva ... | 2008 | 18585795 |
| evaluation of st. louis encephalitis virus/dengue virus type 4 antigenic chimeric viruses in mice and rhesus monkeys. | to develop a live attenuated virus vaccine against st. louis encephalitis (sle) virus, two antigenic chimeric viruses were generated by replacing the membrane precursor and envelope protein genes of dengue virus type 4 (den4) with those from sle with or without a 30 nucleotide deletion in the den4 3' untranslated region of the chimeric genome. chimeric viruses were compared with parental wild-type sle for level of neurovirulence and neuroinvasiveness in mice and for safety, immunogenicity, and p ... | 2008 | 18586359 |
| genetic variation of st. louis encephalitis virus. | st. louis encephalitis virus (slev) has been regularly isolated throughout the americas since 1933. previous phylogenetic studies involving 62 isolates have defined seven major lineages (i-vii), further divided into 14 clades. in this study, 28 strains isolated in texas in 1991 and 2001-2003, and three older, previously unsequenced strains from jamaica and california were sequenced over the envelope protein gene. the inclusion of these new sequences, and others published since 2001, has allowed ... | 2008 | 18632961 |
| detection and serotyping of dengue virus in serum samples by multiplex reverse transcriptase pcr-ligase detection reaction assay. | the detection and successful typing of dengue virus (denv) from patients with suspected dengue fever is important both for the diagnosis of the disease and for the implementation of epidemiologic control measures. a technique for the multiplex detection and typing of denv serotypes 1 to 4 (denv-1 to denv-4) from clinical samples by pcr-ligase detection reaction (ldr) has been developed. a serotype-specific pcr amplifies the regions of genes c and e simultaneously. the two amplicons are targeted ... | 2008 | 18685000 |
| interference between st. louis encephalitis virus and western equine encephalomyelitis virus along a neuronal pathway. | | 1952 | 12981275 |
| a duplex real-time reverse transcriptase polymerase chain reaction assay for the detection of st. louis encephalitis and eastern equine encephalitis viruses. | a duplex taqman real-time reverse transcriptase polymerase chain reaction (pcr) assay was developed for the detection of st. louis encephalitis virus (slev) and eastern equine encephalitis virus (eeev), for use in human and vector surveillance. the respective targets selected for the assay were the conserved ns5 and e1 genes of the 2 viruses. because of the insufficient number of ns5 sequences from slev strains in the genbank database, we determined the sequence of an approximately 1-kb region f ... | 2008 | 18715737 |
| viral parkinsonism. | parkinson's disease is a debilitating neurological disorder that affects 1-2% of the adult population over 55 years of age. for the vast majority of cases, the etiology of this disorder is unknown, although it is generally accepted that there is a genetic susceptibility to any number of environmental agents. one such agent may be viruses. it has been shown that numerous viruses can enter the nervous system, i.e. they are neurotropic, and induce a number of encephalopathies. one of the secondary ... | 2009 | 18760350 |
| real-time reverse-transcription loop-mediated isothermal amplification for rapid detection of rift valley fever virus. | the development and validation of a one-step, single-tube, real-time accelerated reverse-transcription loop-mediated isothermal amplification (rt-lamp) for the detection of the l rna segment of rift valley fever virus (rvfv) are described. the assay was performed at a constant temperature (63 degrees c), with a real-time follow-up using a lightcycler and a double-stranded-dna-intercalating fluorochrome. the assay is highly sensitive and comparable to real-time rt-pcr, with a detection limit of a ... | 2008 | 18799705 |
| identification of genetic determinants of a tick-borne flavivirus associated with host-specific adaptation and pathogenicity. | tick-borne flaviviruses are maintained in nature in an enzootic cycle involving a tick vector and a vertebrate host. thus, the virus replicates in two disparate hosts, each providing selective pressures that can influence virus replication and pathogenicity. to identify viral determinants associated with replication in the individual hosts, plaque purified langat virus (tp21pp) was adapted to growth in mouse or tick cell lines to generate two virus variants, mnbp20 and isep20, respectively. viru ... | 2008 | 18823640 |
| epidemiology of neuroinvasive arboviral disease in the united states, 1999-2007. | from 1999-2007, the most common causes of neuroinvasive arboviral disease in the united states, after west nile virus (wnv), were california (cal) serogroup viruses, st. louis encephalitis virus (slev), and eastern equine encephalitis virus (eeev). the cal serogroup virus disease was primarily reported from appalachia and the upper midwest, slev disease from southern states, and eeev disease from areas along the atlantic and gulf coasts. children accounted for 88% of cal serogroup virus disease, ... | 2008 | 19052314 |
| does variation in culex (diptera: culicidae) vector competence enable outbreaks of west nile virus in california? | since the invasion of california by west nile virus (family flaviviridae, genus flavivirus, wnv) in 2003, we have annually monitored vector competence for the ny99 strain in culex tarsalis coquillett, culex pipiens quinquefasciatus say, culex p. pipiens l., and culex stigmatosoma dyar populations from four areas: deserts of coachella valley, densely urbanized maritime los angeles, southern san joaquin valley in kern county, and southern sacramento valley near davis in sacramento county. overall, ... | 2008 | 19058638 |
| detection of rna from a novel west nile-like virus and high prevalence of an insect-specific flavivirus in mosquitoes in the yucatan peninsula of mexico. | as part of our ongoing surveillance efforts for west nile virus (wnv) in the yucatan peninsula of mexico, 96,687 mosquitoes collected from january through december 2007 were assayed by virus isolation in mammalian cells. three mosquito pools caused cytopathic effect. two isolates were orthobunyaviruses (cache valley virus and kairi virus) and the identity of the third infectious agent was not determined. a subset of mosquitoes was also tested by reverse transcription-polymerase chain reaction (r ... | 2009 | 19141845 |
| 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 ... | 2009 | 19198528 |
| the continuous spread of west nile virus (wnv): seroprevalence in asymptomatic horses. | west nile virus (wnv) was probably introduced in southern and northern mexico from the usa in two independent events. since then, wnv activity has been reported in several mexican states bordering the usa and the gulf of mexico, but disease manifestations seen there in humans and equids are quite different to those observed in the usa. we have analysed wnv seroprevalence in asymptomatic, unvaccinated equids from two mexican states where no data had been previously recorded. wnv igg antibodies we ... | 2009 | 19288961 |
| development of a human-murine chimeric immunoglobulin m antibody for use in the serological detection of human flavivirus antibodies. | current diagnosis of human flaviviral infections relies heavily on serological techniques such as the immunoglobulin m (igm) antibody capture enzyme-linked immunosorbent assay (mac-elisa). broad application of this assay is hindered by a lack of standardized human positive-control sera that react with the wide variety of flaviviruses that can cause human disease, e.g., dengue virus (denv), west nile virus (wnv), yellow fever virus (yfv), japanese encephalitis virus (jev), and st. louis encephali ... | 2009 | 19297614 |
| evaluation of an epitope-blocking enzyme-linked immunosorbent assay for the diagnosis of west nile virus infections in humans. | an epitope-blocking enzyme-linked immunosorbent assay (b-elisa) was evaluated for the diagnosis of west nile virus (wnv) infections in humans. sera from patients diagnosed with wnv infections from an outbreak in 2003 in colorado and from patients diagnosed with dengue virus infections from mexico and thailand were tested with the b-elisa. the b-elisas were performed using the wnv-specific monoclonal antibody (mab) 3.1112g and the flavivirus-specific mab 6b6c-1. although the wnv-specific b-elisa ... | 2009 | 19321694 |
| isolation of genotype v st. louis encephalitis virus in florida. | we isolated and characterized st. louis encephalitis virus (slev) from cloacal swabs of naturally exposed adult sentinel chickens in 2006. phylogenetic analysis of slev strains isolated in florida indicated that brazilian slev circulated in 1972 and 2006; lineages were va and vb. | 2009 | 19331744 |
| 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 ... | 2009 | 19407138 |
| distribution of mosquitoes in relation to urban landscape characteristics. | the current global increase in prevalence of vector borne diseases, as well as an expansion of tropical infections to more temperate zones, justifies further studies on vector populations. urban areas may favour viral transmission to humans through close contacts between the vectors and the vertebrate hosts, and also affecting mosquito populations by offering larval habitat, refuges and adequate microclimates to survive the winter. this work analyses the spatial distribution of potential vector ... | 2010 | 19413916 |
| evaluation of chimeric japanese encephalitis and dengue viruses for use in diagnostic plaque reduction neutralization tests. | the plaque reduction neutralization test (prnt) is a specific serological test used to identify and confirm arbovirus infection in diagnostic laboratories and monitor immunological protection in vaccine recipients. wild-type (wt) viruses used in the prnt may be difficult to grow and plaque titrate, such as the dengue viruses (denv), and/or may require biosafety level 3 (bsl3) containment, such as west nile virus (wnv), st. louis encephalitis virus (slev), and japanese encephalitis virus (jev). t ... | 2009 | 19458204 |
| effect of sequential exposure on infection and dissemination rates for west nile and st. louis encephalitis viruses in culex quinquefasciatus. | west nile virus has spread rapidly throughout the united states since its introduction in 1999, into some areas that are also endemic for st. louis encephalitis virus (slev). these viruses are in the same antigenic complex within the genus flavivirus, family flaviviridae. further, both viruses are transmitted primarily by culex spp. mosquitoes and use birds as amplifying hosts. these viruses could contemporaneously coinfect individual vectors wherein changes in mosquito immune responses might oc ... | 2009 | 19492941 |
| origins of alphavirus-derived small rnas in mosquitoes. | the continual transmission in nature of many arthropod-borne viruses depends on the establishment of a persistent, nonpathogenic infection in a mosquito vector. the importance of antiviral immunity directed by small rnas in the mechanism by which alphaviruses establish a persistent, nonpathogenic infection in the mosquito vector has recently been demonstrated. the origin of the small rnas central to this rna silencing response has recently been the subject of debate. here we briefly summarize wh ... | 2009 | 19535909 |
| effect of pregnancy upon the immunity of mice vaccinated against st. louis encephalitis virus. | | 1952 | 13011696 |
| etiology of acute undifferentiated febrile illness in the amazon basin of ecuador. | we conducted a longitudinal observational study of 533 patients presenting to two hospitals in the ecuadorean amazon basin with acute undifferentiated febrile illness (aufi) from 2001 through 2004. viral isolation, reverse transcription-polymerase chain reaction (rt-pcr), igm seroconversion, and malaria smears identified pathogens responsible for fever in 122 (40.1%) of 304 patients who provided both acute and convalescent blood samples. leptospirosis was found in 40 (13.2%), malaria in 38 (12.5 ... | 2009 | 19556580 |
| propagation of st. louis encephalitis virus in cells of the ehrlich ascitic tumor of mice. | | 1953 | 13120899 |
| cellular inflammatory response to flaviviruses in the central nervous system of a primate host. | flaviviruses such as tick-borne encephalitis virus, japanese encephalitis virus, west nile virus, and st. louis encephalitis virus are important neurotropic human pathogens, typically causing a devastating and often fatal neuroinfection. flaviviruses induce neuroinflammation with typical features of viral encephalitides, including inflammatory cell infiltration, activation of microglia, and neuronal degeneration. development of safe and effective live-virus vaccines against neurotropic flaviviru ... | 2009 | 19581627 |
| prevalence of antibodies to west nile virus and other arboviruses among crested caracaras (caracara cheriway) in florida. | we documented the antibody prevalence to three arboviruses, st. louis encephalitis virus (slev), eastern equine encephalitis virus (eeev), and west nile virus (wnv), in crested caracaras (caracara cheriway; n = 80) in florida from 2007 to 2008. antibody prevalence to wnv was higher (9%) than for the other viruses. most seropositive birds were adults (< or =3 yr of age), with 55% of adults testing positive for antibodies to at least one virus. adults were significantly more likely to have antibod ... | 2009 | 19617494 |
| west nile virus infection alters midgut gene expression in culex pipiens quinquefasciatus say (diptera: culicidae). | alterations in gene expression in the midgut of female culex pipiens quinquefasciatus exposed to blood meals containing 6.8 logs plaque-forming units/ml of west nile virus (wnv) were studied by fluorescent differential display. twenty-six different cdnas exhibited reproducible differences after feeding on infected blood. of these, 21 cdnas showed an increase in expression, and 5 showed a decrease in expression as a result of wnv presence in the blood meal. genbank database searches showed that o ... | 2009 | 19635880 |
| 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 ... | 2009 | 19635881 |
| phase 1 trial of the dengue virus type 4 vaccine candidate rden4{delta}30-4995 in healthy adult volunteers. | rden4delta30-4995 is a live attenuated dengue virus type 4 (denv4) vaccine candidate specifically designed as a further attenuated derivative of the rden4delta30 parent virus. in a previous study, 5 of 20 vaccinees who received 10(5) plaque-forming units (pfu) of rden4delta30 developed a transient elevation of the serum alanine aminotransferase (alt) level and an asymptomatic maculopapular rash developed in 10 of 20. in the current study, 28 healthy adult volunteers were randomized to receive 10 ... | 2009 | 19861619 |
| the limited neurotropic character of the encephalitis virus (st. louis type) in susceptible mice. | 1. st. louis encephalitis virus injected intracerebrally into susceptible mice multiplies there to reach a titre of 10(9) intracerebral lethal doses. it is found also in the blood in small amounts immediately following injection and preceding death. 2. injected intraperitoneally or subcutaneously the virus circulates in the blood for several hours and survives in the spleen for days. it does not multiply in the brain and cause encephalitis, however, unless overwhelming doses are injected or the ... | 1936 | 19870481 |
| multiplication of st. louis encephalitis virus in mice exposed to roentgen radiation. | | 1956 | 13279127 |
| the multiplication of st. louis encephalitis virus in two species of mosquitoes: culex quinque-fasciatus say and culex pipiens linnaeus. | | 1959 | 13835549 |
| community infection with st. louis encephalitis virus. serologic study of the 1964 epidemic in houston. | | 1965 | 14310326 |
| st. louis encephalitis virus in wild birds during the 1990 south florida epidemic: the importance of drought, wetting conditions, and the emergence of culex nigripalpus (diptera: culicidae) to arboviral amplification and transmission. | we analyzed the prevalence of hemagglutination inhibition (hi) antibodies to st. louis encephalitis (sle) virus in wild birds during the 1990 sle epidemic in indian river county. the initial presence of sle hi antibody was associated significantly with modeled drought 15 wk prior, wetting conditions 1 wk prior, and the emergence of the florida sle virus vector, culex nigripalpus, 5 wk prior. our findings indicated that three factors conspired to create the 1990 epidemic: (1) a large population o ... | 2003 | 14680125 |
| experimental infection of california birds with western equine encephalomyelitis and st. louis encephalitis viruses. | a total of 27 bird species from the san joaquin and coachella valleys of california were inoculated subcutaneously with sympatric strains of western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses. overall, 133 of 164 birds inoculated with wee virus developed a viremia detected by plaque assay; significantly greater than 72 of 163 birds inoculated with sle virus. host competence was calculated as the average number of days that each avian species had a viremia > or = 2 lo ... | 2003 | 14765678 |
| wild terrestrial rainforest mammals as potential reservoirs for flaviviruses (yellow fever, dengue 2 and st louis encephalitis viruses) in french guiana. | a serological survey for yellow fever virus (yfv), dengue 2 virus (denv-2), and st louis encephalitis virus (slev) was undertaken using a seroneutralization technique in 27 wild forest mammal species (574 individuals) in french guiana. evidence of yellow fever infection was observed in 10 species, with high prevalence recorded in howler monkey (18%) and agouti (20%). antibodies against denv-2 and slev were found sporadically in various species. this potential host diversity and the range of pote ... | 2004 | 15138077 |
| role of inborn resistance factors in mouse populations infected with bacillus enteritidis. | 1. under conditions in which mouse typhoid is allowed to spread naturally among herds of mice comprised of different proportions of individuals of innately high or low susceptibility: (a) 85 to 95 per cent of the innately susceptible succumb to mouse typhoid in contrast to less than 5 per cent of the innately resistant, regardless of whether either constitutes 25, 50, or 75 per cent of the population respectively. (b) the surviving population is therefore comprised largely of individuals known a ... | 1939 | 19870901 |
| detection of st. louis encephalitis and western equine encephalomyelitis rna in mosquitoes tested without maintenance of a cold chain. | western equine encephalomyelitis and st. louis encephalitis viral rna can be detected 20 days after death of infected culex tarsalis in the absence of a cold chain. viral rna was detected with the reverse transcription-polymerase chain reaction in mosquitoes infected either parenterally or perorally in the laboratory and then killed and held for up to 20 days at 27 degrees c. cell culture assay and in situ enzyme immunoassay did not detect infectious virus in the same mosquitoes. | 2001 | 11804455 |
| genetic characterization of st. louis encephalitis virus isolated from human in são paulo, brazil. | the molecular characterization of sph253157, a new strain of st. louis encephalitis virus (slev), isolated in 2004 from the first case of human infection recognized in the state of são paulo, brazil, is reported. the patient, presenting a febrile illness without neurological involvement, was hospitalized as a probable case of dengue fever. genomic rna was isolated from the supernatant of c6/36 cells infected with acute phase-serum specimen of the patient and the envelope gene was amplified by re ... | 2006 | 16699711 |
| laboratory transmission of st. louis encephalitis virus by three genera of mosquitoes. | 1. st. louis virus has been successfully transmitted in the laboratory by the following 9 species of mosquitoes from 3 genera: culex tarsalis, culex pipiens, culex coronator, aedes lateralis, aedes taeniorhynchus, aedes vexans, aedes nigromaculis, theobaldia incidens, and theobaldia inornata. 2. though transmission has not been demonstrated, survival of the virus for more than a few days was shown to occur in culex quinquefasciatus, culex stigmatosoma, psorophora ciliata, and anopheles maculipen ... | 1943 | 19871325 |
| mutation analysis of the fusion domain region of st. louis encephalitis virus envelope protein. | the immune response to flavivirus infections produces both species-specific and flavivirus cross-reactive antibodies. the presence of cross-reactive antibodies complicates serodiagnosis of flavivirus infections, especially secondary infections caused by a heterologous virus. a successful public health response to the growing global threat posed by flaviviruses necessitates the development of virus-specific diagnostic antigens. the flavivirus envelope (e) glycoprotein is the principle antigen sti ... | 2007 | 17157348 |
| unexpected altered specificity is responsible for st. louis encephalitis virus recombinant protease autoproteolysis. | we report herein the study of the cleavage fragments generated by autoproteolysis of the st. louis encephalitis virus recombinant protease. the cleavage sites leading to truncated forms were identified by microsequencing, which revealed an unexpected altered specificity of the recombinant proteinase towards unusual sequences. | 2007 | 17266653 |
| influence of anesthesia on experimental neurotropic virus infections : i. in vivo studies with the viruses of western and eastern equine encephalomyelitis, st. louis encephalitis, poliomyelitis (lansing), and rabies. | anesthesia with diethyl ether significantly alters the course and outcome of experimental infections with the equine encephalomyelitis virus (eastern or western type) or with the st. louis encephalitis virus. no comparable effect is observed in experimental infections produced with rabies or poliomyelitis (lansing) viruses. the neurotropic virus infections altered by ether anesthesia are those caused by viruses which are destroyed in vitro by this anesthetic, and those infections not affected by ... | 1946 | 19871570 |
| multiplication and spread of the virus of st. louis encephalitis in mice with special emphasis on its fate in the alimentary tract. | 1. beginning at 24 hours after intravenous injection of about 10 million intracerebral ld(50) of virus there was evidence of simultaneous, progressive multiplication in the brain and intestinal tract. 2. when the virus was introduced directly into the brain or the nasal cavities and mouth, none was found in the intestinal tract until there was general centrifugal spread from the central nervous system during the last stages of the infection at 96 or 120 hours after inoculation when the virus in ... | 1947 | 19871641 |
| seroprevalence of west nile virus infection in solid organ transplant recipients. | of people infected with mosquito-borne west nile virus (wnv), <1% develop neuroinvasive disease (nid). population studies suggest that people older than 65 years may be at higher risk for neurologic symptoms. it has been suggested that solid organ transplant (sot) recipients are also at higher risk for wnv nid, but definitive serologic and epidemiologic data are lacking. | 2010 | 19874565 |
| removal of species constraints in antibody detection. | serum antibodies from myriad species, particularly birds, can provide key information regarding the transmission and the expansion of the territory of emerging pathogens. expedient antibody analysis is constrained by a lack of species-specific reagents, a deficiency potentially highlighted by the recent swine-origin influenza a virus (h1n1) outbreak. available methodologies present difficulties that discourage thorough serologic monitoring of potential disease vectors or hosts. rapid high-throug ... | 2010 | 19923570 |
| experimental passage of st. louis encephalitis virus in vivo in mosquitoes and chickens reveals evolutionarily significant virus characteristics. | st. louis encephalitis virus (slev; flaviviridae, flavivirus) was the major cause of epidemic flaviviral encephalitis in the u.s. prior to the introduction of west nile virus (wnv) in 1999. however, outbreaks of slev have been significantly more limited then wnv in terms of levels of activity and geographic dispersal. one possible explanation for these variable levels of activity is that differences in the potential for each virus to adapt to its host cycle exist. the need for arboviruses to rep ... | 2009 | 19924238 |