| preparation and use of a stable, inactivated rift valley fever antigen. | | 1978 | 24056 |
| 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 ... | 1979 | 44038 |
| spread of rift valley fever virus from continental africa. | | 1979 | 91909 |
| 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 ... | 1978 | 215768 |
| 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 ... | 1979 | 262596 |
| 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 ... | 1979 | 262597 |
| immune response of steers, goats and sheep to inactivated rift valley fever vaccine. | | 1979 | 298921 |
| 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. | 1978 | 310725 |
| 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 ... | 1979 | 314354 |
| 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. | 1979 | 314355 |
| 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. | 1977 | 323417 |
| 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 ... | 1977 | 351506 |
| hemorrhagic fevers, with special reference to recent outbreaks in southern africa. | in 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 ... | 1979 | 399369 |
| rift valley fever: the role of the vervet monkey as a reservoir or maintenance host for this virus. | | 1978 | 418540 |
| rift valley fever encephalitis. a description of a case. | | 1979 | 421266 |
| [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 ... | 1979 | 494210 |
| 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. | 1979 | 505918 |
| rift valley fever. a survey for antibody to the virus in bird species commonly found in situations considered to be enzootic. | | 1979 | 531912 |
| susceptibility of cer cell line to rift valley fever virus. | | 1979 | 541587 |
| rift valley fever vaccine--antibody and immune response in cattle to a live and an inactivated vaccine. | in 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 ... | 1979 | 551199 |
| 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 ... | 1978 | 568328 |
| the rift valley fever virus, agent of dengue-like epidemics: its geographical distribution and public health problems. | | 1978 | 572395 |
| virus isolation and identification from cases of rift valley fever virus infection in egypt. | | 1978 | 572404 |
| epidemic of rift valley fever (rvf) in egypt: virological diagnosis of rvf in man. | | 1978 | 572405 |
| 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 ... | 1979 | 575230 |
| 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 ... | 1978 | 632561 |
| rift valley fever: an historical perspective. | | 1978 | 752698 |
| a seroepidemiological study for rift valley fever virus in humans and domestic animals in egypt. | | 1978 | 752699 |
| ecological and epidemiological studies of rift valley fever in egypt. | | 1978 | 752700 |
| seriologic and vector comparisons of rift valley virus with other bunyaviruses. | | 1978 | 752702 |
| propagation of rvf virus in goat kidney cell culture. | | 1978 | 752703 |
| serologic response of man to inactivated rift valley fever vaccine. | | 1978 | 752704 |
| preliminary studies on goat kidney cell culture as a possible substrate for veterinary rvf vaccine. | | 1978 | 752705 |
| 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 ... | 1975 | 1058243 |
| 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. | 1975 | 1144929 |
| duration of immunoglobulin m antibodies against rift valley fever virus in cattle after natural infection. | | 1992 | 1287943 |
| 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 ... | 1992 | 1287944 |
| 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 ... | 1992 | 1297176 |
| 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, ... | 1992 | 1322071 |
| 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 ... | 1992 | 1336040 |
| [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. ... | 1992 | 1339983 |
| rift valley fever virus activity in east africa in 1989. | | 1992 | 1355315 |
| 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 ... | 1992 | 1357176 |
| 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 ... | 1992 | 1361722 |
| 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 ... | 1992 | 1370348 |
| 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 ... | 1992 | 1385686 |
| 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 ... | 1992 | 1413515 |
| rift valley fever antibody in human sera collected after an outbreak in domestic animals in kenya. | | 1992 | 1440789 |
| 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 ... | 1992 | 1448895 |
| 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. | 1992 | 1518967 |
| patterns of rift valley fever activity in zambia. | an 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 ... | 1992 | 1547835 |
| 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 ... | 1992 | 1575297 |
| 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 ... | 1992 | 1620962 |
| 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 ... | 1992 | 1629699 |
| 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 ... | 1992 | 1629699 |
| 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 ... | 1992 | 1642552 |
| 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). | 1991 | 1676073 |
| 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 ... | 1991 | 1686445 |
| rift valley fever on the east coast of madagascar. | in march 1990, a rift valley fever virus (rvfv) outbreak was suspected in the district of fenerive on the east coast of madagascar after an abnormally high incidence of abortions and disease in livestock. sera from humans and cattle were tested for rvfv antibodies by immunofluorescence assay (ifa) and elisa-igm capture. sera and mosquitoes collected in the same area were tested for virus isolation by tissue culture and suckling mouse intracerebral inoculation, and for antigen detection by an eli ... | 1991 | 1687082 |
| 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 ... | 1990 | 1690534 |
| 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 ... | 1991 | 1722089 |
| 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 ... | 1991 | 1759489 |
| 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 ... | 1991 | 1774469 |
| 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 ... | 1991 | 1787408 |
| 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 ... | 1991 | 1803412 |
| 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 ... | 1991 | 1846496 |
| 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]. | | 1991 | 1923828 |
| 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]. | | 1991 | 1923828 |
| bunyaviridae: pathogenesis. | | 1991 | 1935228 |
| 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 ... | 1991 | 2008798 |
| 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 ... | 1991 | 2035749 |
| 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 ... | 1991 | 2045800 |
| 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 ... | 1991 | 2052753 |
| 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 ... | 1991 | 2063951 |
| 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 ... | 1990 | 2077783 |
| [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 ... | 1990 | 2085908 |
| effect of rift valley fever virus on pregnant and non-pregnant local barki ewes after artificial infection. | studies were conducted into effects of rift valley fever virus on oestrous and vaginal cytology in non-pregnant ewes. 6 pregnant and 8 non-pregnant local barki ewes were subcutaneously inoculated with different doses of virus isolated from sharkia province. observed were irregularities in the oestrous cycle (20-28 days inoculation) and anoestrum. the anoestrum smears included large non-cornified epithelial cells with large well stains centrally located nuclei together with a large number of bact ... | 1990 | 2096784 |
| pathogenesis of a phleboviral infection (punta toro virus) in golden syrian hamsters. | the hamster, mesocricetus auratus, was examined as a possible model for investigating the poorly defined pathogenesis of the family bunyaviridae, genus phlebovirus. punta toro virus (ptv) isolates from eastern panama were highly virulent for two outbred and five inbred hamster strains, while isolates from western panama were of low virulence. the adames strain (eastern panama) of ptv (ld50 approximately 1 pfu, sc) caused an acute fatal disease (average survival time, 3.8 days) in 10-week-old lak ... | 1990 | 2122875 |
| [a comparative evaluation of methods for detecting the rift valley fever virus]. | | 1990 | 2219864 |
| generation and transmission of rift valley fever viral reassortants by the mosquito culex pipiens. | reassortant viruses containing heterologous s and m genomic rna segments were obtained from both mosquito and vertebrate hosts that had been coinfected with egyptian and senegalese strains of rift valley fever (rvf) virus. the origin of the s and m rna segments in each plaque-cloned virus was determined with monoclonal antibodies capable of differentiating the nucleocapsid protein (s segment marker) or the g1 glycoprotein (m segment marker) of the parental strains. in the mosquito culex pipiens, ... | 1990 | 2230736 |
| 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 ... | 1990 | 2267972 |
| establishment and characterization of a cell line from the mosquito culex (culex) theileri (diptera: culicidae) and its susceptibility to infection with arboviruses. | the mosquito culex (culex) theileri theobald is probably the major vector of rift valley fever (rvf) virus during epizootics on the inland plateau of southern africa. a cell line was established from the tissues of this mosquito species to facilitate laboratory studies on rvf and other arboviruses. after temperature pretreatment, egg rafts from a laboratory colony were disinfected, mechanically disrupted, and grown in preconditioned eagles minimum essential medium supplemented with 10% fetal cal ... | 1990 | 2280394 |
| 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 ... | 1990 | 2316789 |
| expression strategy of a phlebovirus: biogenesis of proteins from the rift valley fever virus m segment. | the middle (m) rna segment of rift valley fever virus (rvfv) encodes four proteins: the major viral glycoproteins g2 and g1, a 14-kilodalton (kda) protein, and a 78-kda protein. these proteins are derived from a single large open reading frame (orf) present in the virus-complementary m-segment mrna. we used recombinant vaccinia viruses in which sequences representing the m-segment orf were engineered as a surrogate system to study phlebovirus protein expression. to investigate the translational ... | 1990 | 2319645 |
| use of reassortant viruses to map attenuating and temperature-sensitive mutations of the rift valley fever virus mp-12 vaccine. | a live-attenuated vaccine for rift valley fever virus (rvfv), mp-12, has been developed recently by undirected, serial mutagenesis of a rvfv strain (zh548) isolated during the 1977 epidemic in egypt. in the present study, the mutations responsible for attenuation of this virus have been examined by analysis of reassortant viruses generated between the vaccine strain and a wild rvfv strain isolated in senegal. reassortant viruses were generated efficiently in multiply infected vero cells, and wer ... | 1990 | 2396475 |
| prophylactic and therapeutic efficacy of poly(i,c)-lc against rift valley fever virus infection in mice. | the prophylactic and therapeutic efficacy of polyriboinosinic-polyribocytidylic acid stabilized with poly-l-lysine and carboxymethylcellulose [poly(i,c)-lc] was evaluated in female swiss webster mice against a lethal infection of rift valley fever virus (rvfv). prophylactically, the best effect was obtained with 2-3 doses of 1-20 micrograms poly(i,c)-lc, which fully protected the mice in a schedule-dependent fashion against an ld100 rvfv challenge. multiple intermittent therapeutic administratio ... | 1985 | 2416883 |
| prophylaxis of rift valley fever with antiviral drugs, immune serum, an interferon inducer, and a macrophage activator. | rift valley fever virus (rvfv), a member of the family bunyaviridae, extended its range from sub-saharan africa into egypt in 1977. its clinical spectrum is recognized to include severe manifestations such as hemorrhagic fever and encephalitis. for these reasons, as well as the limited knowledge of specific therapy for bunyaviridae infections, we investigated several prophylactic regimens for rvf in a mouse model. rimantadine, thiosemicarbazone, and inosiplex were ineffective. pretreatment with ... | 1986 | 2429616 |
| complement fixing antibodies against arboviruses in horses at lagos, nigeria. | sixty-two sera horse collected from two stables at lagos, nigeria, were tested for complement fixing antibody to 8 arbovirus antigens; chikungunya, igbo-ora, yellow fever, wesselsbron, west nile, potiskum, uganda s and rift valley fever. ten per cent of the horse sera examined contained cf antibody to one or more of the test antigens and indicated considerable arbovirus activity in the two stables. reactions with flavivirus antigens were most common and the highest antibody titres were obtained ... | 1989 | 2485538 |
| toga-like virus as a cause of fulminant hepatitis attributed to sporadic non-a, non-b. | virus-like particles (60-70 nm) with spiked surfaces budding into cell vacuoles and rod-shaped inclusions were detected in nuclei of hepatocytes from a british patient transplanted for sporadic non-a, non-b fulminant hepatitis (nanb-fhf), probably contracted in kenya. identical particles were seen in two successive grafts (days 2 and 10) at regrafting for recurrent fhf. ultrastructural features resembled those of the rna-containing arbovirus, rift valley fever virus, but serological markers agai ... | 1989 | 2502604 |
| 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 ... | 1989 | 2505350 |
| antibodies to haemorrhagic fever viruses in madagascar populations. | sera of 381 adult people from 5 areas in madagascar were tested by the indirect immunofluorescence method for antibodies against congo-crimean haemorrhagic fever and rift valley fever viruses (bunyaviridae), ebola (strains zaire and sudan) and marburg viruses (filoviridae), and lassa virus (arenaviridae). the highest prevalence rate was that of ebola virus (4.5%). as no haemorrhagic syndrome has been found associated with this virus, the possible presence of a less pathogenic, antigenically rela ... | 1989 | 2515626 |
| 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 ... | 1989 | 2519963 |
| epidemiology of hemorrhagic fever viruses. | twelve distinct viruses associated with hemorrhagic fever in humans are classified among four families: arenaviridae, which includes lassa, junin, and machupo viruses; bunyaviridae, which includes rift valley fever, crimean-congo hemorrhagic fever, and hantaan viruses; filoviridae, which includes marburg and ebola viruses; and flaviviridae, which includes yellow fever, dengue, kyasanur forest disease, and omsk viruses. most hemorrhagic fever viruses are zoonoses, with the possible exception of t ... | 1989 | 2546247 |
| prospects for treatment of viral hemorrhagic fevers with ribavirin, a broad-spectrum antiviral drug. | ribavirin, a broad-spectrum antiviral drug, is active against hemorrhagic fever viruses (with the exception of ebola virus) in cell culture systems. in model infections with arenaviruses in guinea pigs and monkeys, ribavirin has demonstrated both prophylactic and therapeutic efficacy. in therapeutic studies it has not prevented late-onset neurologic disease. in human cases of lassa fever, it significantly reduces mortality when administered before day 7 of illness to persons at high risk. in rod ... | 1989 | 2546248 |
| prevention of rift valley fever in rhesus monkeys with interferon-alpha. | prophylactic and therapeutic efficacy of recombinant leukocyte a interferon (rifn-alpha a) and sendai virus-induced human leukocyte interferon (huifn-alpha) administered intramuscularly to rift valley fever virus (rvfv)-infected rhesus monkeys was studied. clinical, virologic, immunologic, and hemostatic parameters were monitored. five daily inoculations of 5 x 10(5) units of either interferon product per kilogram of body weight, initiated 24 hours before or 6 hours after rvfv infection, prevent ... | 1989 | 2546250 |
| arbovirus infections and viral haemorrhagic fevers in uganda: a serological survey in karamoja district, 1984. | sera collected in may 1984 from 132 adult residents of karamoja district, uganda, were examined by haemagglutination inhibition tests for antibodies against selected arboviruses, namely chikungunya and semliki forest alphaviruses (togaviridae); dengue type 2, wesselsbron, west nile, yellow fever and zika flaviviruses (flaviviridae); bunyamwera, ilesha and tahyna bunyaviruses (bunyaviridae); and sicilian sandfly fever phlebovirus (bunyaviridae); and by immunofluorescence tests against certain hae ... | 1989 | 2559514 |
| arbovirus infections and viral haemorrhagic fevers in uganda: a serological survey in karamoja district, 1984. | sera collected in may 1984 from 132 adult residents of karamoja district, uganda, were examined by haemagglutination inhibition tests for antibodies against selected arboviruses, namely chikungunya and semliki forest alphaviruses (togaviridae); dengue type 2, wesselsbron, west nile, yellow fever and zika flaviviruses (flaviviridae); bunyamwera, ilesha and tahyna bunyaviruses (bunyaviridae); and sicilian sandfly fever phlebovirus (bunyaviridae); and by immunofluorescence tests against certain hae ... | 1989 | 2559514 |
| [transmission cycles of arboviruses in madagascar]. | some arboviruses are highly pathogenic for men or animals. arboviruses epidemiological patterns in madagascar were determined by entomological, serological, and virological surveys. we listed potentials arboviruses vectors in madagascar. entomological results generated by us during five years, as well as prior to, are shown. we caught more than 150,000 hematophagous arthropods, belonging to 107 species at least. 3 of these species were new. 4183 inoculation pools were done. we studied serollogic ... | 1989 | 2576622 |
| serological evidence of dengue fever among refugees, hargeysa, somalia. | epidemics of a malaria-like illness affected several thousand residents of the dam camp, a refugee camp near hargeysa in somalia, during 1985, 1986, and 1987. the disease was characterized by fever, chills, sweats, headache, back and joint pains for as long as 10 days in some patients. blood smears from acutely ill patients were negative for malaria. of 28 acute and 10 convalescent sera tested by the indirect fluorescent antibody (ifa) and by the hemagglutination inhibition (hi) tests, all were ... | 1989 | 2600591 |
| efficacy of a sustained-release methoprene formulation on potential vectors of rift valley fever virus in field studies in kenya. | | 1989 | 2614412 |