Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| multiple intracranial calcifications after western equine encephalitis. | 1991 | 2067893 | |
| arboviral infections in the united states. | arboviruses are important considerations in the differential diagnosis of encephalitis and other acute infections. alterations in the environment and in human behaviors contribute to changing patterns of arboviral transmission. these trends, the periodic epidemic resurgence of arboviral diseases such as st. louis encephalitis, and the discovery of new arboviruses present a continued challenge to infectious disease clinicians. | 1991 | 1646839 |
| experimental inoculation of three arboviruses in black-bellied whistling ducks (dendrocygna autumnalis). | wild-caught, immature black-bellied whistling ducks (dendrocygna autumnalis) were inoculated with eastern equine encephalitis (eee), st. louis encephalitis (sle), or western equine encephalitis (wee) virus. susceptibility, duration and titer of viremia, and antibody response to these arboviruses were determined. birds from all inoculated groups became viremic. higher virus titers occurred in the eee group but overall mean titers were not significantly different among experimental groups. all bir ... | 1992 | 1474647 |
| evaluation of domestic pigeons as sentinels for detecting arbovirus activity in southern california. | flocks of sentinel domestic pigeons (columbia livia) detected increases in st. louis encephalitis (sle) and western equine encephalomyelitis (wee) virus activity in southern california concurrently with flocks of sentinel chickens. however, occasional low-titered, transient seroconversions to both wee and sle viruses also occurred in pigeons during periods when virus activity was not detected by seroconversions in sentinel chickens, by virus isolation from culex mosquitoes, or by human disease. ... | 1992 | 1536386 |
| arboviral encephalomyelitides of livestock in the western hemisphere. | 1992 | 1601730 | |
| arboviral disease--united states, 1991. | during 1991, state and local health departments reported 122 cases of human arboviral encephalitis to cdc. more than half (69) of the cases resulted from outbreaks of st. louis encephalitis (sle) in arkansas and texas. in addition, an epizootic of eastern equine encephalitis (eee) extending from the atlantic and gulf coasts into the upper midwest caused sporadic human cases and a substantial loss of livestock. this report summarizes the reported cases of arboviral encephalitis in the united stat ... | 1992 | 1321947 |
| from the centers for disease control. arboviral disease--united states, 1991. | 1992 | 1324995 | |
| mosquito and arbovirus ecology in southeastern california, 1986-1990. | mosquito abundance and western equine encephalomyelitis (wee) and st. louis encephalitis (sle) virus activity were monitored in five valleys in southeastern california from june 1986 through april 1990 to study virus overwintering and possible dissemination from south to north along geographically defined corridors. culex tarsalis coquillett predominated in co2 trap collections and was the only species repeatedly infected with wee and sle viruses. abundance peaked during april-may and august-oct ... | 1992 | 1352557 |
| transmission of western equine encephalomyelitis virus by argentine aedes albifasciatus (diptera: culicidae). | aedes albifasciatus (macquart) has been considered a potential vector of western equine encephalitis (wee) virus in argentina because it has been found naturally infected, it is susceptible to infection per os, and its distribution and feeding habits are compatible with those of an epizootic and epidemic vector. ae. albifasciatus females collected in the vicinity of cordoba, argentina, were highly susceptible to wee virus perorally (id50 less than 0.5 vero cell plaque-forming units) when fed on ... | 1992 | 1404265 |
| pathologic changes in the midgut of culex tarsalis following infection with western equine encephalomyelitis virus. | midguts of two strains of the mosquito vector culex tarsalis were examined by light and electron microscopy following infection with western equine encephalomyelitis virus. infection of the highly susceptible knight's landing strain with high-titered blood meals resulted in pathologic changes in the midgut epithelium after 2-4 days of incubation; lesions included sloughing of epithelial cells into the lumen and necrosis of cells in situ. infection of knight's landing strain mosquitoes with low-t ... | 1992 | 1449210 |
| relationship of cliff swallows, ectoparasites, and an alphavirus in west-central oklahoma. | approximately 250 isolates of a newly recognized virus, related to western equine encephalitis virus (family togaviridae, genus alphavirus), were obtained from cimicid bugs, oeciacus vicarius; cliff swallows, hirundo pyrrhonata; and house sparrows, passer domesticus in a study area in west-central oklahoma at buggy creek and caddo canyons. antigenicity of the virus strains varied slightly from isolate to isolate. this paper summarizes the ecology of the area by describing in general the flora an ... | 1993 | 8381870 |
| [post-epizootic activity of western equine encephalitis virus in argentina]. | it is shown here the wee virus activity in argentina in 1983-1986 post-epizootic period. a surveillance system was established by the equine case notification and the sentinel animal method. among the thirteen equine focus notified between september 1983-september 1985 in córdoba and santa fe provinces, 5 presumptive cases out of 16 sick horses were confirmed by the hemagglutination inhibition test for wee epizootic virus. twenty eight notified human cases were studied with negative results. the ... | 1993 | 8234736 |
| weather factors in the prediction of western equine encephalitis epidemics in manitoba. | cases of western equine encephalitis in horses in 1987 in western usa and manitoba, canada were examined by backward trajectory analysis of winds. culex tarsalis mosquitoes infected with western equine encephalitis virus could have been carried on southerly winds from texas and oklahoma to northern usa and from there to manitoba. the presence of the polar front over north dakota and minnesota at the end of july would have led to the landing of cx. tarsalis in montana and wisconsin and prevented ... | 1993 | 8405163 |
| effect of temperature on the transmission of western equine encephalomyelitis and st. louis encephalitis viruses by culex tarsalis (diptera: culicidae). | the extrinsic incubation rate (inverse of the time in days from infection to median transmission) of western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses by laboratory strains of culex tarsalis coquillett increased as a linear function of incubation temperatures from 10 to 30 degrees c. the estimated temperatures for zero transmission thresholds (intercept of the x axis) were 10.9 and 14.9 degrees c, and the number of degree days above these thresholds required for med ... | 1993 | 8433322 |
| arbovirus surveillance in northern colorado, 1987 and 1991. | arbovirus surveillance was conducted during an epizootic of western equine encephalitis (wee) during 1987 and during a nonepizootic year, 1991, in the same area in northern colorado. mosquitoes were collected in larimer county, co, during weeks 33-37 (10 august to 7 september) in 1987 and during weeks 26-35 (24 june to 26 august) in 1991. in total, 13,099 mosquitoes in 694 pools collected during 1987 and 8,672 mosquitoes in 242 pools collected during 1991 were tested for virus. wee virus was iso ... | 1993 | 8433334 |
| distribution of western equine encephalomyelitis virus in the alimentary tract of culex tarsalis (diptera: culicidae) following natural and artificial blood meals. | the distribution of western equine encephalomyelitis (wee) virus in the alimentary tract of culex tarsalis (coquillett), following blood feeding, was examined using autoradiography. following engorgement on chicks circulating radiolabeled virus, wee virus in all mosquitoes was concentrated at the margins of the abdominal midgut, adjacent to the epithelium. thirty percent of mosquitoes also contained small amounts of virus in the foregut, ventral diverticulum, and/or thoracic midgut. mosquitoes i ... | 1993 | 8459416 |
| western equine encephalomyelitis: virulence markers and their epidemiologic significance. | comparative studies are described on the virulence of the western equine encephalomyelitis (wee) complex viruses for mice. three epizootic wee virus strains (mcmillan, cba 87, and cba civ 180) and five enzootic wee complex viruses (highlands j [hj], y62-33, aura, fort morgan [fm], and wee ag80-646) were examined. the neurovirulence and the neuroinvasiveness of these viruses for adult mice were established and correlated with viremia and virus replication in brain tissue. adult mice inoculated in ... | 1993 | 8103970 |
| a comparison of the nucleotide sequences of eastern and western equine encephalomyelitis viruses with those of other alphaviruses and related rna viruses. | the complete nucleotide sequence of a 1982 florida strain of eastern equine encephalomyelitis (eee) virus, and partial sequence of the nonstructural protein genes of western equine encephalomyelitis (wee) virus, were determined. the eee virus genome was 11,678 nucleotides in length, excluding the cap nucleotide and poly(a) tail, and the nucleotide composition was 28% a, 24% g, 25% c, and 23% u. the organization of both eee and wee virus genomes was like that of other alphaviruses and included a ... | 1993 | 8105605 |
| arbovirus disease--united states, 1993. | during 1993, health departments from 20 states reported 78 cases of arboviral encephalitis to cdc. of these, 55 (71%) were california encephalitis (ce). this report summarizes information about arboviral encephalitis in the united states during 1993. | 1994 | 8183230 |
| [primary structure of proteins of the nsp2 and nsp3 polymerase complex confirm the recombinant nature of western encephalitis virus]. | 1994 | 8025555 | |
| rapid assessment of vectorborne diseases during the midwest flood--united states, 1993. | heavy spring and summer rainfall during 1993 caused the most extensive flash and riverine flooding ever recorded in the upper midwestern united states. in portions of the flood region,* standing water provided large expanses of habitat capable of producing large populations of the mosquitoes culex pipiens and cx. tarsalis. these species can rapidly amplify transmission of the arboviruses that cause st. louis encephalitis (sle) and western equine encephalitis (wee). although information from stat ... | 1994 | 7911970 |
| from the centers for disease control and prevention. rapid assessment of vectorborne diseases during the midwest flood--united states, 1993. | 1994 | 7913143 | |
| pcr-based detection of arboviral rna from mosquitoes homogenized in detergent. | an improved method for the extraction of viral rnas was developed to facilitate the reverse transcription (rt)-pcr detection of mosquitoes infected with western equine encephalitis virus or la crosse virus. the solubilization method, which uses only edta and sodium dodecyl sulfate (sds) followed by dilution of sample, allows accurate viral detection through the use of random hexamers for the rt followed by specific primers for the pcr. identities of the reaction products were confirmed either by ... | 1994 | 7946293 |
| a comparison of the nucleotide sequences of eastern and western equine encephalomyelitis viruses with those of other alphaviruses and related rna viruses. | 1994 | 8030217 | |
| potential effect of global warming on mosquito-borne arboviruses. | if global warming occurs in california, daily mean temperatures may increase by 3 to 5 degrees c, precipitation patterns will change, and sea level may rise 1 m. studies were done on effect of temperature changes on survival of culex tarsalis coquillett, the primary vector of western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses, in two regions where temperatures differed by 5 degrees c. daily mortality of adult vectors increased by 1% for each 1 degree c increase in te ... | 1994 | 8057305 |
| effects of low ph on hemagglutinating and hemolytic activities of west equine encephalomyelitis virus. | 1. the hemagglutinating (ha) and hemolytic (hl) activities mediated by egg-propagated west equine encephalomyelitis (wee) virus preparations were investigated. 2. the purified virus preparation exhibited the best ha and hl activity at ph 6.0 and 6.0-6.2, respectively, as observed in the ha and hl tests. 3. in the virus preparations, both ha and hl activities were completely lost upon pretreatment at low ph (6.0). 4. the present results suggest that the alphavirus-mediated ha and hl activities ag ... | 1994 | 8081285 |
| from the centers for disease control and prevention. arbovirus disease--united states, 1993. | 1994 | 8028127 | |
| western equine encephalitis virus in emus in oklahoma. | 1994 | 7858032 | |
| natural vertical transmission of western equine encephalomyelitis virus in mosquitoes. | the mechanism by which western equine encephalomyelitis (wee) virus and other mosquito-borne alphaviruses (togaviridae) survive during periods of vector inactivity is unknown. recently, three strains of wee virus were isolated from adult aedes dorsalis collected as larvae from a salt marsh in a coastal region of california. this provides evidence of vertical transmission of wee virus in mosquitoes in nature. vertical transmission in ae. dorsalis and closely related mosquito species may be an imp ... | 1994 | 8303276 |
| an epizootic attributable to western equine encephalitis virus infection in emus in texas. | an epizootic of encephalomyelitis attributable to western equine encephalitis virus was identified in emus (dromaius novaehollandiae) from several flocks in western texas in july 1992. affected emus ranged from 3 months to 3 years old. morbidity of emus in 8 flocks ranged from 15 to 50%, and 17 of 193 (8.8%) emus died. the diagnosis was confirmed by isolation and characterization of the causative virus and detection of antibody to the virus in emus that were currently ill and emus that had been ... | 1994 | 7961099 |
| viremia and serological responses in adult chickens infected with western equine encephalomyelitis and st. louis encephalitis viruses. | adult hens, similar to those used for arbovirus surveillance, were experimentally infected with western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses to describe the viremia response, to compare serological testing methods, and to evaluate a new method of collecting whole blood onto filter paper strips from lancet pricks of the chicken comb. young (19 weeks), but not old (38 weeks), hens developed a low-titer, transient viremia for a 1-day period. immunoglobulin g (igg) ... | 1994 | 7707063 |
| susceptibility of the sf9 insect cell line to infection with adventitious viruses. | sf9, the insect cell line commonly used for gene expression by recombinant baculovirus (bv), can be infected by st. louis encephalitis (sle) virus, a flavivirus, resulting in a persistent, productive, and cytopathic infection, while retaining the ability to be infected with a recombinant baculovirus (rbv). we now demonstrate using double immunofluorescence that single cells are dually infected with sle virus and rbv. fourteen additional viruses including additional flaviviruses, other arbovirus ... | 1994 | 7811453 |
| from the centers for disease control and prevention. arboviral disease--united states, 1994. | 1995 | 7563474 | |
| landscape ecology of arboviruses in southern california: temporal and spatial patterns of vector and virus activity in coachella valley, 1990-1992. | consistent temporal and spatial patterns in the activity of culex tarsalis coquillett and western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses were delineated that were useful in developing a stratified surveillance program. vernal increases in cx. tarsalis abundance typically were associated with flooding of saline marshes along the north shore of the salton sea and were followed 6-8 wk later by the onset of wee and sle virus activity. viruses then spread to managed m ... | 1995 | 7616515 |
| landscape ecology of arboviruses in southern california: patterns in the epizootic dissemination of western equine encephalomyelitis and st. louis encephalitis viruses in coachella valley, 1991-1992. | temporal and spatial patterns in the initiation and dissemination of western equine encephalomyelitis and st. louis encephalitis virus activity in coachella valley during 1991 and 1992 were detected by testing pools of host-seeking culex tarsalis coquillett for virus infection and sentinel chickens for seroconversions. both viruses repeatedly were detected first at a salt marsh adjacent to the salton sea in the southeastern corner of the study area and then disseminated to the northwest to fresh ... | 1995 | 7616516 |
| arboviral disease--united states, 1994. | arboviruses are mosquitoborne and tickborne agents that persist in nature in complex cycles involving birds and mammals, including humans. characteristics of arboviral infection include fever, headache, encephalitis, and sometimes death. in 1994, health departments in 20 states reported 100 presumptive or confirmed human cases of arboviral disease to cdc. of these, 76 were california (cal) serogroup encephalitis; 20, st. louis encephalitis (sle); two, western equine encephalomyelitis (wee); one, ... | 1995 | 7643850 |
| [primary structure of the nucleocapsid gene c and the protein coded by it from the western equine encephalomyelitis virus]. | 1995 | 8535272 | |
| antibodies to arthropod-borne encephalitis viruses in small mammals from southern florida. | from 1987 through 1991, blood samples were collected from 10 species of small mammals in indian river country, florida (usa). sera from 1,347 animals were analyzed for hemagglutination-inhibition (hi) antibody to st. louis encephalitis (sle) and eastern equine encephalitis (eee) viruses. of these, 75 (5.6%) were positive for hi antibody to sle virus and 121 (9.0%) were positive for eee antibody. sera from five mammalian species were tested for neutralizing (nt) antibody to sle, eee, highlands j ... | 1996 | 8827668 |
| seasonal variation in the vector competence of culex tarsalis (diptera:culicidae) from the coachella valley of california for western equine encephalomyelitis and st. louis encephalitis viruses. | the vector competence of culex tarsalis coquillett from the coachella valley of california for western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses was monitored monthly from february to november 1993. the concentration of wee virus required to infect 50% of the females increased during summer coincidentally with ambient temperature and was highest during july. transmission rates of wee virus were high during march, low during may-june, and high again during july-septe ... | 1996 | 8667391 |
| arbovirus titer variation in field-collected mosquitoes. | patterns in the distribution of titers in arbovirus-positive mosquito pools were examined. virus isolation records from the division of vector-borne infectious diseases, centers for disease control and prevention, from 1974 through 1993 were used to estimate virus titers in field-collected pools. pools were classified as either low titer (< or = 3.0 log10 plaque-forming units [pfu]/ml) or high titer (> 3.0 log10 pfu/ml). the proportion of virus-positive pools that had high titers varied among th ... | 1996 | 8827588 |
| chimeric sindbis-ross river viruses to study interactions between alphavirus nonstructural and structural regions. | sindbis virus and ross river virus are alphaviruses whose nonstructural proteins share 64% identity and whose structural proteins share 48% identity. starting from full-length cdna clones of both viruses, we have generated two reciprocal sindbis-ross river chimeric viruses in which the structural and nonstructural regions have been exchanged. these chimeric viruses replicate readily in several cell lines. both chimeras grow more poorly than do the parental viruses, with the chimera containing si ... | 1996 | 8892913 |
| [sindbis viruses of various geographic origin and differentiation of them from western equine encephalomyelitis viruses using the polymerase chain reaction]. | comparison of sindbis virus strains isolated in different regions of the world (in africa, australia, and europe, including russia and its nearest neighbors) in the polymerase chain reaction (pcr) by the primary gene structure of proteins nsp1 and e1 and in the neutralization test showed the greatest similarity between geographically close strains isolated in northern europe (kfl, karelia, 1381 and 1388, estonia). sindbis strains ar339 and babanki isolated in africa were similar to each other an ... | 1996 | 8928504 |
| [similarities and differences between western equine encephalomyelitis viruses with respect to genes for nonstructural protein nsp2 and structural proteins c and e2]. | genetic relationships of geographical isolates of the members of wee virus serocomplex (mcmillan, fort morgan, highlands j, and y62-33) were assessed by the polymerase chain reaction (pcr) and restriction analysis of the pcr products. oligonucleotide primers (21 nucleotides in length) were chosen for nsp2, nucleocapsid c, and e2-e1 protein genes based on the known primary structure of the mcmillan 16310-5614 genome (l. uryvayev et al., 1994, 1995). these primers were shown to differentiate well ... | 1996 | 8967065 |
| [recombination of alpha-viruses during mixed infection in cultured cells. formation of hybrid forms of rna of venezuelan equine encephalomyelitis virus and karelian fever virus in the region of genes for nucleocapsid and envelope proteins]. | a recombination of the genomes of vee and kf viruses, two alphaviruses of different serotypes, takes place in mixed infection of chick embryo fibroblasts and vero cells with vaccine strain vee-230 and kf-9298 strain. this recombination resulted in the production of recombinant virions with altered antigenic properties. polymerase chain reaction (pcr) rapidly and effectively detected the hybrid sites of the genome in recombinant viruses. short nucleotide sequences (approximately 20 n. p.) of a kn ... | 1996 | 8999680 |
| [comparative analysis of primary structure of nucleocapsid protein from western equine encephalomyelitis virus and other alphaviruses]. | part of wee virus (strain 16310-5614) genome coding for the nucleocapsid (c) protein was cloned and sequenced in two independent clones. the c gene of wee virus is composed of 77 nucleotides, both for the bfs and 16310 strains, and is 48, 24, 33, 15, 3, and 3 nucleotides shorter than that of venezuelan equine encephalomyelitis (vee), semliki forest, ross river, sindbis, o'nyong-nyong, and eastern equine encephalomyelitis (eee) viruses, respectively. it contains 16 nucleotide changes in compariso ... | 1996 | 8999681 |
| prevalence of antibodies to mosquito-borne encephalitis viruses in residents of the coachella valley, california. | sera from 19 (2.6%) and 118 (16.4%) of 719 outpatients attending clinics in the southeastern coachella valley, california during 1993 and 1994 exhibited igg antibodies to western equine encephalomyelitis and st. louis encephalitis (sle) viruses, respectively, using enzyme immunoassays. however, only seven (1.0%) and 36 (5.0%) outpatients were positive by plaque-reduction neutralization tests (prnts), and seven (1.0%) and 84 (11.7%) outpatients were positive by sera hemagglutination inhibition as ... | 1996 | 9025696 |
| ecology of mosquitoes and lack of arbovirus activity at morro bay, san luis obispo county, california. | during 1994-95, totals of 17,656 adult females and 111,104 adults reared from field-collected immatures comprising 19 species in 4 genera of mosquitoes were collected from morro bay estuary and surrounding environs in san luis obispo county, california. aedes dorsalis was the dominant summer mosquito, whereas aedes squamiger and ae. washinoi were abundant during winter and early spring. host-seeking culex tarsalis were collected infrequently, even though immatures were collected frequently from ... | 1996 | 9046476 |
| [surveillance of st. louis encephalitis, eastern equine and western equine in the province of ciego de avila]. | serological studies were carried out using the haemagglutination inhibition and neutralization tests so as to know the circulation dynamics of some arboviruses with the use of western and eastern equine encephalitis antigens and st louis encephalitis antigens in human serum from sound and symptomatic individuals, as well as from sentinel birds, between 1987 and 1991, and during 1994. 1.7% of the asymptomatic subjects tested presented neutralizing antibodies to to eastern equine and 4.8% to st lo ... | 1996 | 9768280 |
| [capsid glycoprotein of e2 encephalitis virus, western equine: primary structure of gene and its product]. | 1997 | 9471275 | |
| landscape ecology of arboviruses in southeastern california: temporal and spatial patterns of enzootic activity in imperial valley, 1991-1994. | western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses were detected in the imperial valley during the summers of 1991-1994 by isolation from the primary vector, culex tarsalis coquillett, and by the seroconversion of sentinel chickens. enzootic transmission consistently was not detected first each year at sampling sites near specific landscape features such as a heron rookery and other riparian habitats along the new river, sites along the mexican border, or saline and ... | 1997 | 9103761 |
| biological characteristics of an enzootic subtype of western equine encephalomyelitis virus from argentina. | in order to expand our knowledge on the biological characteristics of an enzootic south american subtype of western equine encephalomyelitis (wee) virus, strain ag80-646, we inoculated guinea pigs, rabbits, newborn chickens and vero and chick embryo cell cultures with this and other wee and wee-related viruses. ag80-646 was found apathogenic for guinea pigs even when inoculated intracranially (i.e.) or intraperitoneally (i.p.), and the animals did not develop viraemia. ag80-646 killed rabbits an ... | 1997 | 9199709 |
| mouse and baby chicken virulence of enzootic strains of western equine encephalomyelitis virus from california. | eight enzootic strains of western equine encephalomyelitis (wee) virus isolated from culex tarsalis or aedes melanimon collected in several geographic areas of california were evaluated for their virulence in suckling mice, adult mice, and one-day-old baby chickens. the epidemic fleming strain and the cloned b628(cl 15) variant were used as virulent and avirulent control viruses, respectively, in adult mice. enzootic strains of wee virus were grouped into three phenotypes on the basis of their n ... | 1997 | 9288823 |
| experimental infection of turkey poults with western equine encephalitis virus. | the pathogenicity of a field isolate of western equine encephalitis (wee) virus, which was recovered from a breeder hen during investigations of egg production drops in california turkey flocks, was tested in 2-wk-old turkey poults. no symptoms or mortality were observed in poults inoculated intramuscularly with 4.2 log10 50% embryo lethal doses of virus; however, the infection did result in mild to moderate lymphoid necrosis in the bursa of fabricius and thymus glands beginning on the first day ... | 1997 | 9356702 |
| prevalence of antibodies to western equine encephalomyelitis and st. louis encephalitis viruses in residents of california exposed to sporadic and consistent enzootic transmission. | sera from outpatients attending county health department clinics in areas of california with consistent (imperial valley) and sporadic (sacramento valley) enzootic transmission of western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses exhibited neutralizing antibody prevalence rates of 1.3% (n = 690) and 0.5% (n = 1,066) for wee and 11.0% and 0.8% for sle, respectively. seroprevalence for sle virus in imperial county increased as a function of both age and years of resid ... | 1997 | 9392590 |
| recombinational history and molecular evolution of western equine encephalomyelitis complex alphaviruses. | western equine encephalomyelitis (wee) virus (togaviridae: alphavirus) was shown previously to have arisen by recombination between eastern equine encephalomyelitis (eee)- and sindbis-like viruses (c. s. hahn, s. lustig, e. g. strauss, and j. h. strauss, proc. natl. acad. sci. usa 85:5997-6001, 1988). we have now examined the recombinational history and evolution of all viruses belonging to the wee antigenic complex, including the buggy creek, fort morgan, highlands j, sindbis, babanki, ockelbo, ... | 1997 | 8985391 |
| effects of water quality on the vector competence of culex tarsalis (diptera: culicidae) for western equine encephalomyelitis (togaviridae) and st. louis encephalitis (flaviviridae) viruses. | the effects of water quality during immature development on the vector competence of adult female culex tarsalis coquillett for western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses was evaluated during 6 field and 4 laboratory experiments. immatures of the bakersfield field station laboratory strain and the f1 progeny of field-collected females were reared in the field or laboratory and then infected by feeding on pledgets, after which remnants (head, thorax, abdomen), ... | 1997 | 9439117 |
| structural localization of the e3 glycoprotein in attenuated sindbis virus mutants. | we have determined the three-dimensional structures of the wild-type sindbis virus and two of its mutants that retain the e3 sequence within pe2. using difference imaging between these mutants and the wild-type virus, we have assigned a location for the 64-amino-acid sequence corresponding to e3 in the mutant spike complex. in the wild-type virus, the spike is composed of an e1-e2 heterotrimer. the e3 protein was found to protrude midway between the center of the spike complex and the tips. base ... | 1998 | 9445057 |
| vector competence of aedes dorsalis (diptera: culicidae) from morro bay, california, for western equine encephalomyelitis virus. | in laboratory vector competence studies, aedes dorsalis (meigen) collected from morro bay, ca, did not vertically transmit sympatric strains of western equine encephalomyelitis virus (wee). this population of ae. dorsalis was highly susceptible to oral infection and was a competent horizontal vector of wee. the e2 region of the viral genome of the 3 virus strains isolated from ae. dorsalis in morro bay were closely related genetically to a strain of wee isolated in 1953 from a geographically sep ... | 1998 | 9835696 |
| a single point mutation controls the cholesterol dependence of semliki forest virus entry and exit. | membrane fusion and budding are key steps in the life cycle of all enveloped viruses. semliki forest virus (sfv) is an enveloped alphavirus that requires cellular membrane cholesterol for both membrane fusion and efficient exit of progeny virus from infected cells. we selected an sfv mutant, srf-3, that was strikingly independent of cholesterol for growth. this phenotype was conferred by a single amino acid change in the e1 spike protein subunit, proline 226 to serine, that increased the cholest ... | 1998 | 9425157 |
| african swine fever virus infection in the argasid host, ornithodoros porcinus porcinus. | the pathogenesis of african swine fever virus (asfv) infection in ornithodoros porcinus porcinus was examined in nymphal ticks infected with the asfv isolate chiredzi/83/1. at times postinfection (p.i.) ranging from 6 h to 290 days, ticks or dissected tick tissues were titrated for virus and examined ultrastructurally for evidence of virus replication. the asfv infection rate in ticks was 100% in these experiments, and virus infection was not associated with a significant increase in tick mortal ... | 1998 | 9499019 |
| characterization of modulation of western equine encephalomyelitis virus by culex tarsalis (diptera: culicidae) maintained at 32 degrees c following parenteral infection. | two lines of culex tarsalis coquillett genetically selected for low or high western equine encephalomyelitis (wee) virus production (low viral producer [lvp] or high viral producer [hvp], respectively) modulated wee (i.e., decreased the concentration of virus to < 10(4) plaque-forming units after intrathoracic inoculation). the lvp line modulated wee more than hvp, and modulation was most pronounced at 32 degrees c. at 15 degrees c, viral replication to high titers occurred in both lines. when i ... | 1998 | 9615548 |
| vector-borne disease surveillance and natural disasters. | 1998 | 9621210 | |
| dengue and dengue hemorrhagic fever. | dengue fever, a very old disease, has reemerged in the past 20 years with an expanded geographic distribution of both the viruses and the mosquito vectors, increased epidemic activity, the development of hyperendemicity (the cocirculation of multiple serotypes), and the emergence of dengue hemorrhagic fever in new geographic regions. in 1998 this mosquito-borne disease is the most important tropical infectious disease after malaria, with an estimated 100 million cases of dengue fever, 500,000 ca ... | 1998 | 9665979 |
| ecology of aedes dorsalis (diptera: culicidae) in relation to western equine encephalomyelitis virus in the coachella valley of california. | the ecology of western equine encephalomyelitis virus (wee) was studies during 1994-1996 along a portion of the north shore of the salton sea in coachella valley, california, known to support a focal aedes dorsalis (meigen) population. wee was detected during 1995 by the seroconversion of sentinel chickens concurrently at sites within and outside of the area supporting ae. dorsalis. wee was not detected during 1994 or 1996; neither was wee detected by seroconversion of sentinel rabbits nor by is ... | 1998 | 9701945 |
| seroprevalence of selected disease agents from free-ranging black bears in florida. | sera obtained from 66 free-ranging florida black bears (ursus americanus floridanus) from three geographic areas of florida (usa) between november 1993 and august 1995 were tested for antibodies to 13 disease agents. antibody prevalences were 3 positive of 37 tested (8%) coxiella burnetti, 37 of 66 (56%) toxoplasma gondii, 3 of 61 (5%) bluetongue virus/epizootic hemorrhagic disease virus (btv/ehdv), 4 of 66 (6%) canine adenovirus-type 1, 5 of 66 (8%) canine distemper virus (cdv), 10 of 62 (16%) ... | 1998 | 9706572 |
| a new enzyme immunoassay to detect antibodies to arboviruses in the blood of wild birds. | a new indirect enzyme immunoassay (eia) was developed to screen wild bird sera for antibodies against western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses. the detector antibody was made by immunizing rabbits with serum proteins pooled from single species representatives of four bird orders and was conjugated with horseradish peroxidase to allow visualization with the abts substrate in an eia plate reader set at 405 nm. the detector antibody recognized a wide range of ... | 1998 | 9879069 |
| surveillance for arthropod-borne viral activity in nebraska, 1994-1995. | a 2-yr arbovirus surveillance program was established in nebraska following the midwest flood of 1993. cdc light traps were used to collect mosquitoes at 11 localities throughout nebraska. in 1994, we collected 685,582 mosquitoes, and we tested 1,359 pools of culex mosquitoes for arbovirus infection, with st. louis encephalitis virus isolated from 2 pools collected in scotts bluff county in western nebraska. in 1995, 1,163,741 mosquitoes were collected and 2,788 pools tested, with 36 positive fo ... | 1998 | 9775605 |
| intestinal lesions in a horse associated with eastern equine encephalomyelitis virus infection. | the primary lesions of eastern equine encephalomyelitis (eee) virus infection in the horse are limited to the brain and spinal cord. intestinal lesions in addition to the changes in the central nervous system were found in a 6-month-old male tennessee walking horse. one week prior to death, this colt was vaccinated for eee virus, western equine encephalomyelitis virus, influenza virus, equine rhinopneumonitis virus, and tetanus. the clinical signs consisted of ataxia and rear-end weakness, with ... | 1998 | 9823595 |
| molecular epidemiological studies of veterinary arboviral encephalitides. | recent studies using molecular genetic approaches have made important contributions to our understanding of the epidemiology of veterinary arboviral encephalitides. viruses utilizing avian enzootic hosts, such as western equine encephalitis virus (weev) and north american eastern equine encephalitis virus (eeev), evolve as relatively few, highly conserved genotypes that extend over wide geographic regions; viruses utilizing mammalian hosts with more limited dispersal evolve within multiple genot ... | 1999 | 10204408 |
| egg production drops in breeder turkeys associated with western equine encephalitis virus infection. | egg production drops associated with western equine encephalitis (wee) virus infection occurred in three turkey breeder flocks in california during summer 1993 and again in one flock the following year. egg production losses totaled 8.76%, 9.57%, 9.71%, and 10.12% and were accompanied by an increase in small white-shelled and shell-less eggs. the outbreaks coincided with peak wee virus activity in the state on the basis of statistics compiled by the california department of health services on se ... | 1999 | 10216771 |
| genetic structure of aedes albifasciatus (diptera: culicidae) populations in central argentina determined by random amplified polymorphic dna-polymerase chain reaction markers. | the floodwater mosquito, aedes albifasciatus (macquart), is the main vector of western equine encephalomyelitis virus in argentina. previous studies on the genetic structure of this species using allozymes showed low levels of polymorphism, absence of subpopulations at distinct habitats, and moderate differentiation among localities separated up to 500 km. to examine gene flow using other genetic methods, we analyzed random amplified polymorphic dna-polymerase chain reaction (rapd-pcr) polymorph ... | 1999 | 10337115 |
| genetic variation among isolates of western equine encephalomyelitis virus from california. | the mechanism for long-term maintenance of western equine encephalomyelitis (wee) virus in california was investigated by studying genetic variation in the e2 portion of the genome of 55 strains of wee virus isolated since 1938 from different locations in california. four major lineages were evident: virus strains isolated from the central valley since 1993 and los angeles in 1991 formed lineage a; southern california strains isolated since 1978 and isolates from the central valley from 1978 to ... | 1999 | 10348252 |
| a single chain fv specific against western equine encephalitis virus. | a recombinant single chain fv (scfv) specific against western equine encephalitis virus (wee) was developed and characterized. the scfv was generated from 11d2 hybridoma producing anti-wee antibody reactive to e1 component of viral envelope glycoprotein. v(l) and v(h) gene segments of 11d2 scfv were generated and joined together with a (gly4ser)3 linker by polymerase chain reaction (pcr). the resulting scfv was successfully expressed in p. pastoris expression system. fifteen individual plasmids ... | 1999 | 10571261 |
| comparative genomics of streptococcus thermophilus phage species supports a modular evolution theory. | the comparative analysis of five completely sequenced streptococcus thermophilus bacteriophage genomes demonstrated that their diversification was achieved by a combination of dna recombination events and an accumulation of point mutations. the five phages included lytic and temperate phages, both pac site and cos site, from three distinct geographical areas. the units of genetic exchange were either large, comprising the entire morphogenesis gene cluster, excluding the putative tail fiber genes ... | 1999 | 10482618 |
| a single amino acid change in nsp1 attenuates neurovirulence of the sindbis-group alphavirus s.a.ar86. | s.a.ar86, a member of the sindbis group of alphaviruses, is neurovirulent in adult mice and has a unique threonine at position 538 of nsp1; nonneurovirulent members of this group of alphaviruses encode isoleucine. isoleucine was introduced at position 538 in the wild-type s.a.ar86 infectious clone, ps55, and virus derived from this mutant clone, ps51, was significantly attenuated for neurovirulence compared to that derived from ps55. intracranial (i.c. ) s55 infection resulted in severe disease, ... | 2000 | 10756033 |
| serologic survey for selected infectious disease agents in swift and kit foxes from the western united states. | a serologic survey of swift fox (vulpes velox) and kit fox (v. macrotis) from the western usa was conducted for 12 infectious diseases. samples from swift fox were collected between 1987 and 1992 from colorado (n = 44), kansas (n = 10), and wyoming (n = 9). samples from kit fox were collected in california (n = 86), new mexico (n = 18), utah (n = 9), and arizona (n = 6). overall antibody prevalence rates were 33 of 110 (30%) for canine parvovirus (cpv), 9 of 72 (13%) for canine distemper virus ( ... | 2000 | 11085448 |
| longevity and spontaneous flight activity of culex tarsalis (diptera: culicidae) infected with western equine encephalomyelitis virus. | the longevity of an iowa strain of culex tarsalis coquillett fed blood meals containing 2 concentrations of western equine encephalomyelitis virus from iowa (wee-7738) was compared with that of cx. tarsalis fed blood without virus. females exposed to 4.7-5.0 log tcid50 per mosquito of wee-7738 did not live as long as mosquitoes exposed to 2.7-3.0 log tcid50 per mosquito or controls. only 1% of mosquitoes fed blood containing the higher virus concentration survived to day 18 after exposure. howev ... | 2000 | 15218926 |
| vector competence of culex tarsalis (diptera: culicidae) from iowa for a sympatric strain of western equine encephalomyelitis (wee-7738) virus. | experiments were designed to evaluate the vector competence of culex tarsalis coquillet from an area (sioux city) where cx. tarsalis is most abundant in iowa for western equine encephalomyelitis virus (wee-7738). wee-7738 was isolated from aedes trivittatus (coquillet) collected in ames, ia, in 1977. infection rate, dissemination rate, multiplication efficiency, and transmission rate were determined for this virus in the sc strain of cx. tarsalis. sc strain of cx. tarsalis was as susceptible to ... | 2000 | 15218927 |
| complete genomic rna sequence of western equine encephalitis virus and expression of the structural genes. | the complete nucleotide sequence of the 71v-1658 strain of western equine encephalitis virus (wee) was determined (minus 25 nucleotides from the 5' end). a 5' race reaction was used to sequence the 5' terminus from wee strain cba87. the deduced wee genome was 11508 nucleotides in length, excluding the 5' cap nucleotide and 3' poly(a) tail. the nucleotide composition was 28% a, 25% c, 25% g and 22% u. comparison with partial wee sequences of strain 5614 (nsp2-nsp3 of the nonstructural region) and ... | 2000 | 10640553 |
| role of peridomestic birds in the transmission of st. louis encephalitis virus in southern california. | in response to the 1984 st. louis encephalitis (sle) epidemic in the los angeles basin of southern california (usa), an investigative program was initiated to evaluate the interactive components of the sle virus transmission cycle. from 1987 through 1996 (10 yr), 52,589 birds were bled and their sera tested for sle and western equine encephalomyelitis (wee) virus antibodies by the hemagglutination inhibition (hai) test. eighty-three percent of the birds tested were house finches (carpodacus mexi ... | 2000 | 10682741 |
| method of infection does not alter response of chicks and house finches to western equine encephalomyelitis and st. louis encephalitis viruses. | the effects of method of infection and virus dose on the viremia and antibody responses of 1-wk-old chicks and after-hatching-year house finches to infection with western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses were studied under laboratory conditions. using a capillary tube technique, females from 2 strains of culex tarsalis coquillett mosquitoes were estimated to expectorate from 1.0 to 1.7 log10 plaque forming units (pfu) of wee and from 1.9 to 2.2 log10 pfu of ... | 2000 | 10730496 |
| response of house finches to infection with sympatric and allopatric strains of western equine encephalomyelitis and st. louis encephalitis viruses from california. | adult house finches from kern county were inoculated subcutaneously with recent sympatric and allopatric isolates of western equine encephalomyelitis and st. louis encephalitis (sle) viruses made from culex tarsalis coquillett collected in kern county and coachella valley, ca, respectively. virulence, as measured by the amplitude of the viremia response during days 1 and 2 postinfection, varied significantly among strains, but independently of geographic origin. the intensity of the immune respo ... | 2000 | 10730497 |
| development of reverse transcription-pcr assays specific for detection of equine encephalitis viruses. | specific and sensitive reverse transcription-pcr (rt-pcr) assays were developed for the detection of eastern, western, and venezuelan equine encephalitis viruses (eee, wee, and vee, respectively). tests for specificity included all known alphavirus species. the eee-specific rt-pcr amplified a 464-bp region of the e2 gene exclusively from 10 different eee strains from south and north america with a sensitivity of about 3,000 rna molecules. in a subsequent nested pcr, the specificity was confirmed ... | 2000 | 10747138 |
| spectrum of virus inhibition by consensus interferon ym643. | the spectrum of viruses inhibited by a genetically engineered consensus interferon (ifn) ym643 (interferon alfacon-1) was evaluated using a cytopathic effect inhibition assay or plaque inhibition assay for five dna viruses and 12 rna viruses. this activity was compared to that of natural ifn-alpha derived from namalwa lymphoblastoid cell line [ifn-alpha (namalwa)]. the viruses inhibited by both ifns were herpesvirus types 1 and 2, human cytomegalovirus, varicella-zoster virus, vesicular stomatit ... | 2000 | 11142632 |
| a single intramuscular injection of recombinant plasmid dna induces protective immunity and prevents japanese encephalitis in mice. | plasmid vectors containing japanese encephalitis virus (jev) premembrane (prm) and envelope (e) genes were constructed that expressed prm and e proteins under the control of a cytomegalovirus immediate-early gene promoter. cos-1 cells transformed with this plasmid vector (je-4b clone) secreted jev-specific extracellular particles (eps) into the culture media. groups of outbred icr mice were given one or two doses of recombinant plasmid dna or two doses of the commercial vaccine jevax. all mice t ... | 2000 | 10756038 |
| the use of chimeric venezuelan equine encephalitis viruses as an approach for the molecular identification of natural virulence determinants. | venezuelan equine encephalitis (vee) virus antigenic subtypes and varieties are considered either epidemic/epizootic or enzootic. in addition to epidemiological differences between the epidemic and enzootic viruses, several in vitro and in vivo laboratory markers distinguishing the viruses have been identified, including differential plaque size, sensitivity to interferon (ifn), and virulence for guinea pigs. these observations have been shown to be useful predictors of natural, equine virulence ... | 2000 | 10756040 |
| relationships among weather, mosquito abundance, and encephalitis virus activity in california: kern county 1990-98. | the summer abundance of culex tarsalis in kern county, california, during 1990-98 was related quantitatively to rainfall, snow depth and water content, and runoff of the kern river. total monthly rain that fell during winter, lagged by 4-6 months, explained only 13% of the variability in the number of host-seeking females collected per trap night per month during summer. in contrast, regression analysis showed that river runoff 1 month earlier explained 67% of the variability in mosquito abundan ... | 2000 | 10757487 |
| construction and characterization of a novel recombinant single-chain variable fragment antibody against western equine encephalitis virus. | a novel recombinant single-chain fragment variable (scfv) antibody against western equine encephalitis virus (wee) was constructed and characterized. using antibody phage display technology, a scfv was generated from the wee specific hybridoma, 10b5 e7e2. the scfv was fused to a human heavy chain igg1 constant region (ch1-ch3) and contained an intact 6 his tag and enterokinase recognition site (rs10b5hufc). the rs10b5hufc antibody was expressed in e. coli and purified by affinity chromatography ... | 2000 | 10768836 |
| construction and characterization of monoclonal antibodies against western equine encephalitis virus. | a repertoire of mouse monoclonal antibodies (mabs) against western equine encephalitis virus (wee) was constructed and characterized. anti-wee antibodies were expressed from hybridomas and purified by protein g chromatography. each of the antibodies was functionally assessed by indirect enzyme-linked immunosorbent assays (elisas), western blotting, and immunoprecipitations. all antibodies bound to wee antigen in elisas, whereas only a subgroup of antibodies was found to be active in western blot ... | 2000 | 10868791 |
| patterns of avian seroprevalence to western equine encephalomyelitis and saint louis encephalitis viruses in california, usa. | temporal and spatial changes in the enzootic activity of western equine encephalomyelitis (wee) and st. louis encephalitis (sle) viruses were monitored at representative wetland study sites in the coachella, san joaquin, and sacramento valleys of california from 1996 to 1998 using three methods: (1) virus isolation from pools of 50 host-seeking culex tarsalis coquillett females, (2) seroconversions in flocks of 10 sentinel chickens, and (3) seroprevalence in wild birds collected by mist nets and ... | 2000 | 10916291 |
| [serological survey on arbovirus infection in residents of an ecological reserve]. | serological inquires conducted in the ribeira valley, s. paulo state, brazil, showed an intense circulation of pathogenic arboviruses in the region. the goal was to verify the prevalence of arboviral infections in people living at the local ecological, and its potential association with these population' individual and familiar characteristics. | 2000 | 10920445 |
| rapid detection of west nile virus from human clinical specimens, field-collected mosquitoes, and avian samples by a taqman reverse transcriptase-pcr assay. | the authors report on the development and application of a rapid taqman assay for the detection of west nile (wn) virus in a variety of human clinical specimens and field-collected specimens. oligonucleotide primers and fam- and tamra-labeled wn virus-specific probes were designed by using the nucleotide sequence of the new york 1999 wn virus isolate. the taqman assay was compared to a traditional reverse transcriptase (rt)-pcr assay and to virus isolation in vero cells with a large number ( app ... | 2000 | 11060069 |
| pharmacokinetics study of a novel chimeric single-chain variable fragment antibody against western equine encephalitis virus. | a novel recombinant single-chain fragment variable (scfv) antibody against western equine encephalitis (wee) virus has been previously constructed and partially characterized. the rs10b5hufc antibody was made by fusing an anti-wee scfv to a human heavy-chain igg1 constant region. the rs10b5hufc antibody was functional in binding to wee virus in enzyme-linked immunosorbent assays (elisas), and the fc domain of the antibody was capable of effector functions, such as binding to protein g and human ... | 2001 | 11289221 |
| response to and efficacy of vaccination against eastern equine encephalomyelitis virus in emus. | to evaluate humoral immune responses of emus vaccinated with commercially available equine polyvalent or experimental monovalent eastern equine encephalomyelitis (eee) virus and western equine encephalomyelitis (wee) virus vaccines and to determine whether vaccinated emus were protected against challenge with eee virus. | 2001 | 11345313 |
| encephalitis virus persistence in california birds: preliminary studies with house finches. | field-collected house finches of mixed sex and age were infected experimentally with either western equine encephalomyelitis (wee) or st. louis encephalitis (sle) viruses during the summer or fall of 1998 and maintained over the winter under ambient conditions. to detect natural relapse during the spring, 32 birds were bled weekly from february through june 1999, and then necropsied 1 yr after infection to detect chronic infections using a reverse transcription polymerase chain reaction (rt-pcr) ... | 2001 | 11372964 |
| inhibition by agaricus blazei murill fractions of cytopathic effect induced by western equine encephalitis (wee) virus on vero cells in vitro. | anti-viral activities of agaricus blazei murill were investigated. the water extracts of the cultured mycelia and fruiting bodies were fractionated with different concentrations of ethanol. to several viruses which have cytopathic effects (cpe) on vero cells, inhibition of these effects by the ethanol fractions was tested. strong inhibition of cpe induced by western equine encephalitis (wee) virus was observed in the mycelial fractions but not those of fruiting bodies. | 2001 | 11515550 |
| evolutionary relationships and systematics of the alphaviruses. | partial e1 envelope glycoprotein gene sequences and complete structural polyprotein sequences were used to compare divergence and construct phylogenetic trees for the genus alphavirus. tree topologies indicated that the mosquito-borne alphaviruses could have arisen in either the old or the new world, with at least two transoceanic introductions to account for their current distribution. the time frame for alphavirus diversification could not be estimated because maximum-likelihood analyses indic ... | 2001 | 11581380 |
| 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 |
| exposure to low ph is not required for penetration of mosquito cells by sindbis virus. | it is widely held that the penetration of cells by alphaviruses is dependent on exposure to the acid environment of an endosome. the alphavirus sindbis virus replicates in both vertebrate and invertebrate cell cultures. we have found that exposure to an acid environment may not be required for infection of cells of the insect host. in this work, we investigated the effects of two agents (nh(4)cl and chloroquine), which raise the ph of intracellular compartments (lysosomotropic weak bases) on the ... | 2001 | 11160702 |
| arbovirus of marine mammals: a new alphavirus isolated from the elephant seal louse, lepidophthirus macrorhini. | a novel alphavirus was isolated from the louse lepidophthirus macrorhini, collected from southern elephant seals, mirounga leonina, on macquarie island, australia. the virus displayed classic alphavirus ultrastructure and appeared to be serologically different from known australasian alphaviruses. nearly all macquarie island elephant seals tested had neutralizing antibodies against the virus, but no virus-associated pathology has been identified. antarctic division personnel who have worked exte ... | 2001 | 11287559 |