the use of cattle to protect sheep from bluetongue infection.studies on the host preferences of culicoides imicola, the vector of bluetongue virus in south africa, are reviewed. there is agreement that this species prefers to feed on cattle but will also feed on other bovidae and sheep. over a seven year period cattle kept near sheep on a natal farm appear to have appreciably reduced the incidence of bluetongue in the sheep. in addition to immunization this "decoy" approach is therefore recommended to assist in the protection of stock from insect borne di ...1978215768
viral haemorrhagic fevers of man.this article reviews the current state of knowledge on the viral haemorrhagic fevers that infect man, namely smallpox, chikungunya fever, dengue fever, rift valley fever, yellow fever, crimean haemorrhagic fever, kyasanur forest disease, omsk haemorrhagic fever, argentinian haemorrhagic fever (junin virus), bolivian haemorrhagic fever (machupo virus), lassa fever, haemorrhagic fever with renal syndrome, and marburg and ebola virus diseases.1978310725
rift valley fever. a survey for antibody to the virus in bird species commonly found in situations considered to be enzootic. 1979531912
pathogenicity of different strains of rift valley fever virus in swiss albino mice.laboratory mice were inoculated with 3 different strains of rift valley fever virus (rvfv): namely, the prototype, the nigerian, and the lunyo variant strains of rvfv. animals were inoculated with either infective mouse brain or serum by the i.c. or i.p. route and organs of inoculated animals examined for virus content and histopathological changes. animals inoculated with either the classical or the nigerian encephalitis only, to a ditropism involving mild lesions in the brain and liver or the ...1979508592
an epizootic of rift valley fever in egypt in 1977.a disease causing increased mortality and abortion in domestic animals during a 1977 epizootic in egypt was identified as rift valley fever (rvf) virus. the epizootic included extensive human involvement reflected clinically as either an acute febrile, ocular, encephalitic, or fatal haemorrhagic form of rvf disease. the virus was again isolated from humans and animals during a second rvf epizootic in the summer of 1978.1979505918
[rift valley fever, a veterinary and medical problem (author's transl)].rift valley fever probably occurred in east and south africa for many years, where it occasionally caused sever epizootics among sheep and to a less extent in cattle and goats. particularly newborn animals fall victims to the disease, whereas the majority of pregnant ewes and cows abort. in recent years, the disease spread to the sudan and reached the nile delta in 1977, where it not only caused an epizootic but also an epidemic among the population, resulting in approximately 18,000 cases and n ...1979494210
rift valley fever virus: some ultrastructural observations on material from the outbreak in egypt 1977.rift valley fever virus isolates from the 1977 outbreak in egypt were studied at an ultrastructural level. the particles measured 90 to 110 nm in diam. using negative staining and sectioning techniques, with a core component of 80 to 85 nm. the surface of the virions was calculated to be covered by approx. 160 sub-units. the particles were found in smooth endoplasmic reticular systems, which were made up of either multi-tubular complexes, or of a single large vacuole. the majority of these membr ...1979422955
rift valley fever encephalitis. a description of a case. 1979421266
rift valley fever: the role of the vervet monkey as a reservoir or maintenance host for this virus. 1978418540
ecological and epidemiological studies of rift valley fever in egypt. 1978752700
seriologic and vector comparisons of rift valley virus with other bunyaviruses. 1978752702
propagation of rvf virus in goat kidney cell culture. 1978752703
serologic response of man to inactivated rift valley fever vaccine. 1978752704
preliminary studies on goat kidney cell culture as a possible substrate for veterinary rvf vaccine. 1978752705
hemorrhagic fevers, with special reference to recent outbreaks in southern considering the diagnosis of a patient admitted to the johannesburg hospital, suffering from an illness characterized by high fever and complicated by a hemorrhagic state from which he died, a list of possible causes of his illness was drawn up. this list included the arthropodborne viral infections prevalent in southern africa, namely, chikungunya fever, sindbis fever, west nile fever, yellow fever, and rift valley fever; viral infections associated with rodents, such as lassa fever; the vir ...1979399369
hydrops amnii in sheep associated with hydranencephaly and arthrogryposis with wesselsbron disease and rift valley fever viruses as aetiological agents.during the 1974/75 lambing season numerous reports were received from various parts of the republic of south africa and south west africa of severe abdominal distension in ewes after vaccination with the attenuated rift valley fever and/or attenuated wesselsbron disease vaccine. the ewes were vaccinated at different stages of gestation in spite of recommendations to the contrary, the syndrome being especially obvious in ewes immunized with one or both of these vaccines during the first trimester ...1977351506
demonstration of nuclear immunofluorescence in rift valley fever infected cells.eosinophilic intranuclear filaments described previously in rift valley fever infected cells, were shown to fluoresce specifically in an indirect technique with antiserum to the virus. actinomycin d failed to suppress development of the filaments or replication of the virus.1977323417
an epidemic of rift valley fever in egypt. 2. isolation of the virus from animals.during the epidemic of rift valley fever (rvf) that occurred in egypt and other areas of north africa in 1977, the virus was isolated from various species of domestic animal and rats (rattus rattus frugivorus) as well as man. the highest number of rvf virus isolates were obtained from sheep; only one isolate was recovered from each of the other species tested, viz. cow, camel, goat, horse, and rat. rvf virus was reisolated from both camel and horse sera, apparently for the first time.1979314355
an epidemic of rift valley fever in egypt. 1. diagnosis of rift valley fever in man.rift valley fever (rvf) virus was isolated from 53 of 56 sera collected from patients with a clinical picture of dengue-like illness during the peak of the epidemic of rvf in egypt in the autumn of 1977. rvf virus was also isolated from the throat washings of two patients and the faeces of four, all of whom were positive for virus isolation from the serum. all the isolates were identified by the complement fixation (cf) test. serological diagnosis of rvf, using paired sera from 16 patients, was ...1979314354
immune response of steers, goats and sheep to inactivated rift valley fever vaccine. 1979298921
immunological reactions of rift valley fever virus strains from east and west africa.three strains of rift valley fever virus, namely nigerian (nig), smithburn's neurotropic (snt), and lunyo variant (lun) were compared by complement fixation (cf), neutralisation (n), haemagglutination/haemagglutination-inhibition (ha/hi) and agar gel diffusion (agd) tests. they showed reciprocal cross-reactivity in cf tests. in n tests, using immune sheep sera, there was reciprocal cross-neutralisation between the nig and snt strains, but not with the lun strain, the antiserum of which neutralis ...1979262597
clinical, virological and serological response of the west african dwarf sheep to experimental infection with different strains of rift valley fever virus.west african dwarf sheep were inoculated with three different strains of rift valley fever virus (rvfv). using infective mouse serum as the source of virus classical rvfv disease characterised by sudden onset, a sharp but transient febrile response, viraemia, abortions and the development of specific rvfv antibodies in surviving animals was observed. the severity of clinical response was, however, dependent on the strain of virus used, with animals inoculated with smithburn's neuroadapted strain ...1979262596
spread of rift valley fever virus from continental africa. 197991909
the rift valley fever epizootic in egypt 1977-78. 2. ecological and entomological studies.epidemiological factors related to the introduction, spread and maintenance of rift valley fever (rvf) virus were studied during the 1977-78 epizootic in egypt, culex pipiens is the most ubiquitous and prevalent mosquito species in the nile valley and delta. isolation of rvf virus from unengorged c. pipiens, and demonstration of laboratory transmission of the virus by this species, strongly implicate it as the chief vector in egypt. virus transmission to man also occurs by contamination when han ...197944038
preparation and use of a stable, inactivated rift valley fever antigen. 197824056
virus isolation and identification from cases of rift valley fever virus infection in egypt. 1978572404
[serological survey of rift valley fever in sheep on the ivory coast].a serological survey of rift valley fever was carried out in sheep in côte-d'ivoire. thousand and fifty one seras collected between 1988 and 1990 in the south of the country were tested for igg and igm by elisa with two objectives: determining the incidence of the rift valley fever and analysing the role of this virus in reproductive failure and abortion. the incidence rate was 6.85%. no difference was found between the three different geographic areas nor between the three years of the survey. ...19921339983
the rift valley fever virus, agent of dengue-like epidemics: its geographical distribution and public health problems. 1978572395
virus-dependent mortality in rift valley fever, eastern equine encephalomyelitis, and chikungunya virus-inoculated mosquito (diptera: culicidae) larvae.the effect of inoculation of mosquito larvae with rift valley fever (rvf) virus on survival to the adult stage was evaluated in aedes aegypti (l.), ae. fowleri (charmoy), ae. mcintoshi huang, ae. taeniorhynchus (wiedemann), ae. triseriatus (say), eretmapodites quinquevittatus theobald, anopheles albimanus wiedemann, and culex pipiens l. pupation rates were similar for rvf virus-inoculated and diluent-inoculated larvae of all mosquito species tested except cx. pipiens. however, with the exception ...19921357176
a preliminary report on an epidemic of rift valley fever (rvf) in egypt. 1977569679
rift valley fever virus infections in egypt: pathological and virological findings in man.ten strains of rift valley fever virus were isolated from serum samples from acute human cases collected during an epidemic of undifferentiated febrile illness. post-mortem samples were obtained from two fatal infections. severe liver necrosis, interstitial pneumonia and myocardial degeneration were seen. rift valley fever virus was isolated from post-mortem samples of liver, cerebro-spinal, pericardial and pleural fluid and from a throat swab. the virus was also isolated from nasopharyngeal was ...1978568328
susceptibility of cer cell line to rift valley fever virus. 1979541587
the rift valley fever epizootic in egypt 1977-78. 1. description of the epizzotic and virological studies.from october to december 1977, an extensive epizootic occurred in egypt resulting in abortions and increased mortality in domestic animals, and severe clinical disease with fatalities in man. rift valley fever (rvf) virus was isolated and identified as the causative agent. in humans, acute febrile, encephalitic, ocular and fatal haemorrhagic diseases were documented as resulting from rvf virus infection. a retrospective serological survey indicated rvf was recently introduced into the area. the ...1979538803
rift valley fever antibody in human sera collected after an outbreak in domestic animals in kenya. 19921440789
epidemic of rift valley fever (rvf) in egypt: virological diagnosis of rvf in man. 1978572405
studies on rift valley fever in some african murids (rodentia: muridae).brains, spleens and livers of 2214 murids, 27 shrews and 7 dormice, trapped at 7 sites in rhodesia, were tested in 277 pools for the presence of rift valley fever virus. there were no isolations of rift valley fever, but 69 isolations of an unidentified virus were obtained. sixteen out of 867 sera had low-titre haemagglutination-inhibition activity against rift valley fever antigen, but only one out of 1260 sera had neutralizing antibody. the evidence suggests that murids fail to encounter infec ...1978632561
rift valley fever: an historical perspective. 1978752698
a seroepidemiological study for rift valley fever virus in humans and domestic animals in egypt. 1978752699
epidemic of rift valley fever (rvf) in egypt: isolation of rvf virus from animals. 1978752707
studies on goats experimentally infected with r.v.f. virus. 1978752709
an inactivated rift valley fever vaccine.the immunising potency of an inactivated rift valley fever (rvf) vaccine prepared from rvf virus infected mouse brain and rvf infected cell culture was studied in cattle and sheep. different doses and adjuvants were compared. in laboratory trials both cattle and sheep developed neutralising antibodies against virulent rvf virus and in cattle antibodies were still detectable 9 months after immunisation. although the immunity produced was inadequate to prevent viraemia after challenge, evidence of ...1977874947
antibodies to rift valley fever virus in swedish u.n. soldiers in egypt and the sinai.swedish united nations emergency forces soldiers serving in egypt and the sinai peninsula were serologically tested for hemagglutination-inhibiting antibodies to rift valley fever (rvf) virus. eight of 170 were positive. rvf has not been reported outside africa, and a survey of 500 swedish soldiers who had not served in the middle east or africa revealed no rvf virus antibodies. there were extensive rvf epidemics in egypt in 1977 and 1978, and it is considered that these serologically positive s ...1979575230
rift valley fever vaccine--antibody and immune response in cattle to a live and an inactivated a study of the response in cattle to a live and an inactivated rift valley fever (rvf) vaccine prepared from cell cultures infected with rvf virus, the effects of varying doses and combinations of these vaccines were compared. the antibody response to a primary injection of either vaccines was poor when measured by the serum virus neutralization test (svn) and the haemagglutination-inhibition test (hi) but a booster dose of inactivated vaccine evoked a good anamnestic response in cattle previ ...1979551199
rift valley fever affecting humans in south africa: a clinicopathological study. 1977561445
observations on the epidemiology of rift valley fever in kenya.the epizootic range of rift valley fever in kenya is defined from the results of virus isolations during epizootics, and form an extensive serological survey of cattle which were exposed during an epizootic. a study of the sera from a wide range of wild bovidae sampled immediately after the epizootic, showed that they did not act as reservoir or amplifying hosts for rvf. virus isolation attempts from a variety of rodents proved negative. rift valley fever did not persist between epizootics by pr ...19751058243
rift valley fever epizootic in the central highlands of madagascar.between february and april 1991, unusual numbers of bovine abortion around antananarivo (central highlands, madagascar) were reported by official veterinary services. rift valley fever (rvf) virus isolations were made from sixteen aborted foetuses and one dead calf in different foci. using monoclonal antibodies, the isolated viruses were found to be different from the 1979 rvf strains isolated in madagascar from mosquitoes and human laboratory infection, and closer to african rvf strains. in a b ...19921297176
[rift valley fever in madagascar in 1991. sero-epidemiological studies in cattle].rift valley fever (rvf) virus was detected for the first time in madagascar in 1979, but without any impact on human and animal populations. however, in 1990 and 1991, several outbreaks with massive cattle abortions were described. since that period, seroepidemiological surveys have been conducted on the east coast and in the highlands (outbreak areas), in the high cattle density regions, and in the national slaughter house in antananarivo. a high rvf igm antibody prevalence was detected in the ...19921301622
rift valley fever virus activity in east africa in 1989. 19921355315
experimental rift valley fever in west african dwarf sheep.west african dwarf sheep were challenged with a low mouse brain-passaged rift valley fever virus (ib-ar 55172) isolated from nigeria. viraemia, mild febrile reaction and neutralising antibodies were demonstrated in inoculated animals.19751144929
the prevalence of arboviral, rickettsial, and hantaan-like viral antibody among schoolchildren in the nile river delta of egypt.a serosurvey was conducted during october and november 1989 to estimate the prevalence of selected arboviral, rickettsial, and hantaan viral antibody among a sample of schoolchildren from 4 villages in the bilbeis area of the nile river delta, egypt. blood specimens were obtained from subjects aged 8 to 14 years. enzyme immunoassay testing of the sera indicated that the prevalence of antibody was 9% (21/223) for sicilian sandfly fever, 4% (8/223) for rift valley fever, 3% (15/437) for west nile ...19921363163
infectious enveloped rna virus antigenic chimeras.random insertion mutagenesis has been used to construct infectious sindbis virus structural protein chimeras containing a neutralization epitope from a heterologous virus, rift valley fever virus. insertion sites, permissive for recovery of chimeric viruses with growth properties similar to the parental virus, were found in the virion e2 glycoprotein and the secreted e3 glycoprotein. for the e2 chimeras, the epitope was expressed on the virion surface and stimulated a partially protective immune ...19921370348
dipeptide backbone conformation and antibody recognition of a viral octapeptide epitope.the peptide ykgtmdsg (tyr-lys-gly-thr-met-asp-ser-gly) represents an important antigenic determinant from the glycoprotein g2 of the pathogenic rift valley fever virus. by preparing a series of single-residue substitution peptides, the importance to antigenicity of individual residues within this octapeptide has been determined. here, we investigated a simple and rapid computational analysis to test for correlations between the observed antigenicity of the substitution analogue peptides and the ...19921384748
impact of stressful conditions on the survival of culex pipiens exposed to rift valley fever virus.several groups of rift valley fever (rvf) virus-exposed and unexposed culex pipiens were allowed differential access to a carbohydrate food source and their survival monitored. when stressed by deprivation of a carbohydrate source, mean survival times of rvf virus-exposed mosquitoes were consistently higher than those of unexposed mosquitoes in each of the carbohydrate-deficient experiments. these differences were statistically significant when mosquitoes were provided 5% sucrose for 24 hours. m ...19911787408
potential role of immunomodulators for treatment of phlebovirus infections of animals.rift valley fever (rvfv) is a major phlebovirus-induced epizootic disease of domestic animals (primarily cattle and sheep) in africa. no therapies for the disease are known. a related phlebovirus, punta toro virus (ptv), has been adapted to induce an rvfv-like disease in c57bl/6 mice. this ptv infection has been used as a model for rvfv because it is reasonably safe and does not require high-level biologic containment. the infection model has been used to study the potential role of immunomodula ...19921385686
analysis of 3' and 5' ends of n and nss messenger rnas of toscana phlebovirus.the 5' and 3' ends of n and nss mrnas, transcribed from the s segment of toscana phlebovirus, were analyzed by oligonucleotide primer extension and s1 nuclease mapping procedures. the results showed that both mrnas acquired, at their 5' end, approximately 9-15 nucleotides not present in the viral template, suggesting an initiation transcription mechanism similar to the one described for influenza virus. furthermore, the 3' ends of the two mrnas were located in a sequence motif conserved in the s ...19921413515
duration of immunoglobulin m antibodies against rift valley fever virus in cattle after natural infection. 19921287943
[biological parameters of patients infected by the rift valley fever virus in rosso (mauritania)]. 19921480580
serological evidence in sheep suggesting phlebovirus circulation in a rift valley fever enzootic area in burkina faso.within the phlebovirus serogroup, rift valley fever (rvf) virus is endemo-enzootic in the african sahelian zone. recently an rvf epizootic in west africa prompted a serosurvey in the major sheep and cattle raising areas. because of the close antigenic relationship between the phleboviruses it appeared of interest to evaluate the prevalence of the other phleboviruses also. in 1987, 482 sheep serum samples were collected in 2 different ecological zones of burkina faso and tested for the presence o ...19921287944
arbovirus isolations from mosquitoes collected during 1988 in the senegal river basin.during august and september 1988, we collected adult mosquitoes from 14 locations in the senegal river basin to search for evidence of rift valley fever (rvf) viral activity one year after the 1987 outbreak, which occurred along the senegal-mauritania border. more than 62,000 specimens representing 18 species in seven genera were collected with carbon dioxide-baited, solid-state army miniature light traps and sheep-baited traps. twenty virus isolations from culex, aedes, and anopheles mosquitoes ...19921361722
patterns of rift valley fever activity in hypothesis that there was an annual emergence of rift valley fever virus in zambia, during or after the seasonal rains, was examined with the aid of sentinel cattle. serum samples taken during 1974 and 1978 showed evidence of epizootic rift valley fever in zambia, with more than 80% positive. a sentinel herd exposed from 1982 to 1986 showed that some rift valley fever occurred each year. this was usually at a low level, with 3-8% of the susceptible cattle seroconverting. in 1985-6 more than 2 ...19921547835
an immunocytochemical study of the distribution of rift valley fever virus in the mosquito culex pipiens.the dissemination of rift valley fever (rvf) virus in females of the epidemic vector culex pipiens was studied immunocytochemically. among orally infected specimens, viral antigen was detected in all major midgut regions, although individuals varied with respect to which regions were infected. among specimens with disseminated infections (infections beyond the midgut epithelium), antigen was detected in most tissues, including those of the nervous and endocrine systems. however, no antigen was f ...19921575297
comparison of the pathogenicity for pregnant sheep of rift valley fever virus and a live attenuated vaccine.a live attenuated mutant of rift valley fever virus, mv p12, was previously shown to be non-pathogenic in young lambs, but capable of producing protective immunity. the studies reported here show that the abortion in sheep caused by an infection with virulent virus is the result of necrosis of the maternal villi and cotyledons arising from an acute inflammation of the maternal caruncles. pregnant ewes infected with the attenuated mutant virus mv p12 showed none of these lesions in the placenta a ...19921620962
nucleotide sequence and coding strategy of the uukuniemi virus l rna segment.the complete nucleotide sequence of the l rna segment of uukuniemi virus has been determined from cloned cdna. the l rna is 6423 nucleotides in length, and is of negative polarity. the viral-complementary rna contains a single large open reading frame of 2104 codons which corresponds to the l protein (m(r) 241039). comparison with the l protein sequences of other members of the bunyaviridae showed homology with the rift valley fever phlebovirus l protein (38% amino acid identity), but no detecta ...19921629699
nucleotide sequence and coding strategy of the uukuniemi virus l rna segment.the complete nucleotide sequence of the l rna segment of uukuniemi virus has been determined from cloned cdna. the l rna is 6423 nucleotides in length, and is of negative polarity. the viral-complementary rna contains a single large open reading frame of 2104 codons which corresponds to the l protein (m(r) 241039). comparison with the l protein sequences of other members of the bunyaviridae showed homology with the rift valley fever phlebovirus l protein (38% amino acid identity), but no detecta ...19921629699
changes in rift valley fever neutralizing antibody prevalence among small domestic ruminants following the 1987 outbreak in the senegal river basin.following the rift valley fever (rvf) epizootic of 1987 in the senegal river basin, 2 series of serosurveys were carried out. in 1988 and 1989, respectively, 303 and 331 randomly selected sheep and goats were investigated and sera tested for the presence of specific rvf-virus-neutralizing antibodies. in 1988, 24.4% of the sera was found to have anti-rvf neutralizing antibodies and in 1989, 19.3% was found. in 1988, we observed in the dagana district, including the 1987 epizootic area, a signific ...19912052753
rift valley fever virus-induced encephalomyelitis and hepatitis in calves.three calves (nos. 1, 2 = 7 days old; no. 3 = 21 days old) were inoculated subcutaneously with virulent rift valley fever (rvf) virus. all calves became viremic and clinically ill, but the two 7-day-old calves were moribund and were euthanatized subsequently on post-inoculation day (pid) 3. highest viral titers were measured in the serum, with lesser concentrations in the brain, heart, spleen, and liver of these animals. viral antigens were detected by immunohistochemical analysis only in the li ...19921448895
isolation of rift valley fever virus from mosquitoes (diptera: culicidae) collected during an outbreak in domestic animals in kenya.during an outbreak of rift valley fever (rvf) in livestock near lake naivasha, rift valley province, kenya, 61,347 mosquitoes (1,287 pools) collected in co2-baited light traps yielded seven viral isolates. five isolates of rvf virus were recovered from 18,831 culex zombaensis theobald and one from 14,439 mansonia africana (theobald). one isolate of a bunyamwera group virus was recovered from 1,175 aedes quasiunivittatus (theobald).19911676073
[evaluation of indicators of health in the area of trarza during the epidemic of rift valley fever in 1987].randomized epidemiological studies conducted inside the rift valley fever epidemic area permitted an estimate of the different epidemiological rates. for the town of rosso, the total number of infected persons was estimated at 9,320, the total number of symptomatic diseases at 1,013 and the number of deaths at 47. the minimal number of deaths for the area which had access to the hospital was 232. the immunity rate in the town was 34.89% after the epidemic. the elisa test was used to test human a ...19902085908
nonvascular delivery of rift valley fever virus by infected determine whether virus-transmitting mosquitoes inoculate infectious particles extravascularly or directly into the vascular system, we permitted mosquitoes infected with rift valley fever virus to feed on the distal third of the tails of suckling mice. amputation of the distal half of the tail within 5 min after their being bitten significantly increased mouse survival as compared with that of mice whose tails remained intact. even when tails were amputated 10 or more min after mosquito feed ...19921503187
electron microscopic identification of zinga virus as a strain of rift valley fever virus.electron microscopic examination of a negatively stained suspension of zinga virus showed particles 90-100 nm in diameter, enveloped with spikes 12-20 nm in length and 5 nm in diameter. further identification of the virus by immune electron microscopy showed the reactivity of human rift valley fever virus-positive serum with zinga virus. results of this study are in agreement with earlier reports that zinga virus is a strain of rift valley fever virus.19921518967
a new genotype of japanese encephalitis virus from indonesia.primer-extension sequencing of the rna template of polio, dengue, rift valley fever, and japanese encephalitis (je) viruses has provided new information on their geographic distribution, origin, and evolution. in a previous study of 46 diverse je virus strains, we demonstrated the existence of three distinct je genotypes in asia. we now report the occurrence of a fourth genotype. in the present study, 19 je virus isolates, representing various geographic regions of asia and a 50-year time span, ...19921322071
the synergistic neutralization of rift valley fever virus by monoclonal antibodies to the envelope glycoproteins.a panel of monoclonal antibodies (mabs) mapping to different antigenic sites on the rvfv g1 and g2 proteins were used to examine the mechanisms involved in neutralization of the virus. three types of synergistic neutralization of rvfv were observed on mixing various pairs of mabs. firstly, enhanced neutralization occurred for two mab pairs that showed augmented binding for g2. these comprised a combination of a neutralizing mab with a non-neutralizing antibody, as well as two antibodies which we ...19921642552
a study of the effect of chemical inactivants on the epitopes of rift valley fever virus glycoproteins using monoclonal antibodies.a panel of 23 monoclonal antibodies (mabs) was used to study the effect of formalin, beta propriolactone (bpl) and binary ethylenimine (bei) on the epitopes of the rift valley fever virus glycoproteins. after the initial inactivation period bei had very little adverse affect on the epitopes whereas bpl significantly altered seven and formalin partially changed the conformation or accessibility of most of the epitopes. the epitopes of all of the inactivated antigens showed a reduced activity agai ...19911723736
recoverability of rift valley fever and sandfly fever sicilian viruses from infected phlebotomus papatasi (diptera: psychodidae) trapped in various oils.we studied the effects of various oils used to trap sand flies on the recovery of virus from infected adult phlebotomus papatasi. both rift valley fever and sandfly fever sicilian viruses were readily recovered from virus-inoculated specimens held at 26 degrees c on mineral, olive or castor oil-soaked sheets for up to 12 h. however, after 50 h on oil-soaked paper, significantly greater titers were recovered from sand flies trapped with mineral oil than from sand flies trapped with either of the ...19921316427
[epidemiology of rift valley fever in west africa. 1. serological investigation of small ruminants in niger].a serosurvey of rift valley fever virus infection conducted among 557 sheep and 643 goats from niger in 1986 points out that 2.8% of the 1,200 animals tested had rvf virus reacting antibodies. the circulation of the virus is demonstrated, as well for another phlebovirus related to rvf virus, the strain arumowot.19911764749
mosquito species collected from a marsh in western kenya during the long rains.a total of 475,431 mosquitoes representing 8 genera and 43 species were collected from a marsh in the western kenya highlands to determine species composition and succession in relation to the epidemiology of rift valley fever virus. culex pipiens was the most common species, totalling 92.3% of the collection, followed by cx. zombaensis (2.2%), anopheles coustani (1.1%), an. squamosus (0.8%), mansonia uniformis (0.6%), coquillettidia microannulatus (0.5%), uranotaenia mashonaensis (0.5%), ma. af ...19911686445
antigenic analysis of rift valley fever virus isolates: monoclonal antibodies distinguish between wild-type and neurotropic virus strains.rift valley fever virus (rvfv) isolates from southern africa were analysed for possible strain variation using monoclonal antibodies prepared against the south african prototype rvf 1830 strain. by the indirect immunofluorescence antibody assay and neutralization tests, the wild type southern african isolates were found to be antigenically similar to rvfv strains from other parts of africa. in contrast, differences in several biologically important neutralizing and haemagglutination epitopes on ...19911803412
antiviral (rna) activity of selected amaryllidaceae isoquinoline constituents and synthesis of related substances.a series of 23 amaryllidaceae isoquinoline alkaloids and related synthetic analogues were isolated or synthesized and subsequently evaluated in cell culture against the rna-containing flaviviruses (japanese encephalitis, yellow fever, and dengue viruses), bunyaviruses (punta toro, sandfly fever, and rift valley fever viruses), alphavirus (venezuelan equine encephalomyelitis virus), lentivirus (human immunodeficiency virus-type 1) and the dna-containing vaccinia virus. narciclasine [1], lycoricid ...19921336040
palmitoylation of cysteine 69 from the cooh-terminal of band 3 protein in the human erythrocyte membrane. acylation occurs in the middle of the consensus sequence of f--i-iiclavl found in band 3 protein and g2 protein of rift valley fever of the major physiologic functions of erythrocytes is the mediation of chloride-bicarbonate exchange in the transport of carbon dioxide from the tissues to the lungs. the anion exchange is mediated by a typical polytopic transmembrane protein in the cell membrane, designated band 3. a carboxyl-terminal peptide of band 3 was affinity-labeled with pyridoxal phosphate, a substrate for the anion transport system, and then sequenced (kawano, y., okubo, k., tokunaga, f., miyata, t., iwanaga, s., a ...19911885574
efficacy of a rift valley fever virus vaccine against an aerosol infection in rats.the formalin-inactivated rift valley fever virus (rvfv) vaccine, tsi-gsd-200, was administered subcutaneously to highly susceptible adult wistar-furth rats (ld50-1 p.f.u., zh501 strain). vaccine was administered on days 0, 7 and 28, the same time course used for at-risk personnel. six months postimmunization, when the serum plaque-reduction neutralization titre (prnt)80 had declined to low or undetectable levels, rats were challenged with 4.4 log10 p.f.u. of the virulent zh501 strain in a nose-o ...19911759489
recombinant human interferon-gamma modulates rift valley fever virus infection in the rhesus monkey.prophylactic treatment of rhesus macaques with 10(4)-10(6) u/kg of recombinant human interferon-gamma (rhuifn-gamma) modulated rift valley fever (rvf) virus infection. ifn was given intramuscularly at 24 h prior to infection and daily thereafter for a total of five doses. after infection, treated monkeys showed no evidence of clinical disease; some had no detectable viremia; when viremia was observed, peak virus titers were decreased compared to control infected monkeys; and only minor and trans ...19911774469
completion of the genome sequence of rift valley fever phlebovirus indicates that the l rna is negative sense and codes for a putative transcriptase-replicase [corrected]. 19911923828
application of polar-orbiting, meteorological satellite data to detect flooding of rift valley fever virus vector mosquito habitats in kenya.measurements of green-leaf vegetation dynamics recorded by the advanced very high resolution radiometer instruments onboard national oceanic and atmospheric administration satellites 7 and 9 were used to derive ground moisture and rainfall patterns in kenya and monitor resultant flooding of mosquito larval habitats (dambos) likely to support rift valley fever virus vector mosquitoes (aedes and culex spp.). satellite-derived data from mid-1981 to december 1988 have been analysed with correspondin ...19901983457
further evaluation of a mutagen-attenuated rift valley fever vaccine in sheep.a previous study demonstrated that a mutagen-attenuated rift valley fever virus (rvfv) vaccine, rvf mp-12, was immunogenic and non-abortogenic when ewes, 90-110 days pregnant, were inoculated with 5 x 10(5) plaque-forming units (p.f.u.) of the virus strain. the ewes delivered live, healthy lambs that had no neutralizing antibody to rvfv until after they had ingested colostrum. to assess further the safety and protective capability of this candidate vaccine, six pregnant ewes were inoculated with ...19912008798
ability of a mutagenized virus variant to protect young lambs from rift valley fever.a live attenuated vaccine virus variant of rift valley fever (rvf) virus was developed by passaging a human isolate in tissue culture under the influence of the mutagen 5-fluorouracil. this virus variant (mv p12) has been assessed in this study as to its suitability as a vaccine, by testing its pathogenicity in young lambs and measuring its ability to induce a protective immune response. even high doses of the vaccine virus failed to induce any of the clinical or histopathologic changes associat ...19912021254
antibody prevalence against haemorrhagic fever viruses in randomized representative central african populations.between 1985 and 1987, 5,070 randomly selected persons living in 6 central african countries (cameroon, central african republic, chad, congo, equatorial guinea and gabon) were checked for serological evidence of haemorrhagic fever. rural and urban areas were studied, including ecoclimatic zones ranging from dry savana to tropical rain forest. virus-reactive antibodies were found with all antigens tested, and the global prevalence of positive sera was distributed as follows: crimean-congo haemor ...19892505350
potential for mosquito transmission of attenuated strains of rift valley fever virus.studies were conducted to determine if two attenuated strains of rift valley fever (rvf) virus could be transmitted by culex pipiens mosquitoes. both strains (rvf mp 12 and t1) replicated in and were transmitted by female cx. pipiens after intrathoracic inoculation. mosquitoes also became infected with and transmitted the rvf mp12 strain after ingesting virus from a blood-soaked cotton pledget. however, because of the low viremias produced in infected animals, it is unlikely that mosquitoes woul ...19912035749
egg hatching of aedes mosquitoes during successive floodings in a rift valley fever endemic area in kenya.floodwater aedes breeding habitats in central kenya were sequentially flooded to determine the numbers of mosquito eggs hatching during each flooding. approximately 90% of the larvae sampled during 4 floodings emerged during the initial flooding. the number of aedes eggs hatching during the second flooding was lowest of all 4 floodings, and no significant differences in the amount of egg hatching during floodings 3 and 4 were seen. unhatched aedes eggs were present in soil samples collected afte ...19912045800
sequences and coding strategies of the s rnas of toscana and rift valley fever viruses compared to those of punta toro, sicilian sandfly fever, and uukuniemi viruses.the sequences and coding strategies of the s rnas of two viruses, toscana (tos) and the m12 derivative of rift valley fever zh-548 (rvf, phlebovirus genus, bunyaviridae) have been determined from cdna clones and compared to the previously published sequences of punta toro (pt), sandfly fever sicilian (sfs), and uukuniemi (uuk) viruses. all five viruses exhibit an ambisense coding strategy for their small (s) rna species, i.e., one gene product (the nss protein) is encoded in the 5' half of the v ...19911846496
infection of inbred rat strains with rift valley fever virus: development of a congenic resistant strain and observations on age-dependence of resistance.a congenic rat strain (wf.lew) was derived from the susceptible wistar-furth (wf) (background strain) and the resistant lew (donor strain) inbred strains and was used to evaluate the phenotypic expression of a dominant mendelian gene that confers resistance to fatal hepatic disease caused by the zh501 strain of rift valley fever virus (rvfv). resistance to hepatic disease developed gradually with age, with full expression at approximately 10 weeks in the wf.lew and lew rat strains. the zh501 str ...19912063951
completion of the genome sequence of rift valley fever phlebovirus indicates that the l rna is negative sense and codes for a putative transcriptase-replicase [corrected]. 19911923828
transmission of rift valley fever virus by different geographic strains of culex pipiens in egypt.previous investigations have delt with colonized cx. pipiens and rvf virus interactions. this study evaluated the vector competence of parental cx. pipiens populations for rvf virus and investigated variations in the vector competence among different geographic strains of this mosquito in egypt. cx. pipiens females were fed on viremic hamsters circulating 9.4-10.5 log10 smicld50 of virus. mosquito samples were freezed at different intervals extending between 0-12 days of extrinsic incubation (ei ...19892519963
pretreatment of floodwater aedes habitats (dambos) in kenya with a sustained-release formulation of methoprene.effectiveness of sustained-release altosid pellets (4% ai methoprene) against floodwater mosquitoes in dambos treated at 5, 3, and 1 wk before and 1 day after flooding was determined. only 2% of aedes pupae (primarily aedes mcintoshi) survived to adults in an area treated 5 wk preflood, and no adult mosquitoes emerged from an area treated 1 day after flooding. in contrast, 12 and 16% of aedes pupae successfully survived to the adult stage in areas pretreated 3 and 1 wk, respectively, preflood. t ...19902098486
characterization of baculovirus-expressed rift valley fever virus glycoproteins synthesized in insect cells.a cdna corresponding to the complete coding region of the m rna of the m12 mutant of rift valley fever virus (rvfv) strain zh548 (k. takehara, m-k. min, j.k. battles, k. sugiyama, v.c. emery, j.m. dalrymple, and d.h.l. bishop, virology, 169, 452-457, 1989) has been inserted into the baculovirus transfer vector pacym1. by comparison with the parent rvfv, the m rna of the m12 mutant has a new small open reading frame (orf1) upstream of the one that initiates the precursor of the viral glycoprotein ...19902077783
pathogenesis of rift valley fever in rhesus monkeys: role of interferon response.rhesus monkeys inoculated intravenously with rift valley fever (rvf) virus presented clinical disease syndromes similar to human cases of rvf. all 17 infected monkeys had high-titered viremias but disease ranged from clinically inapparent to death. three (18%) rvf virus-infected monkeys developed signs of hemorrhagic fever characterized by epistaxis, petechial to purpuric cutaneous lesions, anorexia, and vomiting prior to death. the 14 remaining monkeys survived rvf viral infection but, 7 showed ...19901690534
topological mapping of antigenic sites on the rift valley fever virus envelope glycoproteins using monoclonal antibodies.a panel of 17 monoclonal antibodies (mabs) to the g1 and g2 envelope glycoproteins of rift valley fever (rvf) virus were used to analyze the topography and functional properties of the viral antigenic sites. four heterogeneous antigenic regions which may be interlinked were identified on the g1 protein and four distinct domains on the g2 protein by competitive binding assays. comparison of the biological activities and epitope specificities of the mabs against g1 showed that the antigenic domain ...19911722089
transmission of rift valley fever virus by adult mosquitoes after ingestion of virus as larvae.we studied the ability of culex pipiens, aedes circumluteolus, and ae. mcintoshi, exposed as larvae to liver tissue from a rift valley fever (rvf) virus-infected hamster, to become infected and transstadially transmit virus to the adult and for the adults to transmit virus by bite to hamsters. after exposure as larvae, 9% (5/54) of adult cx. pipiens and 8% (38/505) of the adult ae. (neomelaniconion) species were infected. all of the infected cx. pipiens and about half of the infected ae. circuml ...19902267972
bunyaviridae: pathogenesis. 19911935228
baculovirus expression of the m genome segment of rift valley fever virus and examination of antigenic and immunogenic properties of the expressed proteins.autographa californica nuclear polyhedrosis viral recombinants containing coding information for the rift valley fever virus (rvfv) envelope glycoproteins (g1 and g2) and varying amounts of preglycoprotein coding sequences were prepared by using transfer vectors pac373 or pacym1. expression products were processed to yield proteins indistinguishable from authentic g1 and g2 by gel electrophoresis. the immunogenic properties of the expressed proteins were assessed by immunizing mice and challengi ...19892655274
transmission of rift valley fever virus by the sand fly, phlebotomus duboscqi (diptera: psychodidae).studies were conducted to determine if the sand fly phlebotomus duboscqi could serve as a vector of rift valley fever (rvf) virus. when 145 p. duboscqi were fed on a hamster with rvf viremia (approximately 10(9) pfu/ml of blood), 72 (50%) became infected. of 5 with disseminated infections (i.e., virus recovered from their legs) 4 transmitted virus to hamsters by bite. sand flies were uniformly infected when rvf virus was inoculated by the intrathoracic route, and each of 31 sand flies so inocula ...19902316789
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