Publications

TitleAbstractYear
Filter
PMID(sorted descending)
Filter
recommendations for african horse sickness vaccines for use in nonendemic areas.african horse sickness (ahs), which causes mortality up to 95%, is caused by orbiviruses and is transmitted by culicoides. the goal of a control and eradication program for ahs is to prevent the spread of the virus via the biological vector. control measures include slaughter of infected animals, housing of suspected infected animals in insect-proof stalls, and vaccination. vaccination has played a key role in eradication when ahs occurred outside of africa. both modified live vaccines (mlv) and ...19938134660
the use of african horse sickness virus vp7 antigen, synthesised in bacteria, and anti-vp7 monoclonal antibodies in a competitive elisa.a full-length cdna clone of genome segment 7 of african horse sickness virus, serotype 9 (ahsv9) was obtained using the pcr technique. the clone was sequenced and found to be 98.27% homologous to the previously published sequence of the equivalent cdna clone from ahsv4 at the nucleotide level and to exhibit 99.7% identity at the amino acid level. the cdna clone was transferred to pgex-2t (pharmacia), a bacterial expression vector, such that the reading frame of ahsv9 vp7 was continuous with that ...19938113344
haemagglutination-inhibiting antibodies against african horse sickness virus in domestic animals in nigeria.a sero-epidemiological survey of african horse sickness (ahs) virus in 261 animals which included 96 camels, 81 horses, 80 dogs and 4 donkeys was carried out in nigeria. the animals had no history of vaccination against ahs. sera were tested by the haemagglutination-inhibition (hi) test for the presence of antibody against ahs virus. of these, 77 (95.1%) horse, 4 (100%) donkey, 10 (10.4%) camel and 28 (35%) dog sera samples tested were recorded as positive. the prevalence of antibody in samples ...19938111431
african horse sickness: transmission and epidemiology.african horse sickness (ahs) virus causes a non-contagious, infectious, arthropod-borne disease of equines and occasionally of dogs. the virus is widely distributed across sub-saharan african where it is transmitted between susceptible vertebrate hosts by the vectors. these are usually considered to be species of culicoides biting midges but mosquitoes and/or ticks may also be involved to a greater or lesser extent. periodically the virus makes excursions beyond its sub-saharan enzootic zones bu ...19938102076
detection of african horsesickness virus by reverse transcriptase polymerase chain reaction (rt-pcr) using primers for segment 5 (ns1 gene).the reverse transcription followed by the polymerase chain reaction (rt-pcr) technique was applied to the detection of african horsesickness virus (ahsv) using primers specific for attenuated ahsv serotype 4 segment 5 (ns1 gene). total rna which contains both messenger rna and genomic dsrna was extracted by the acid guanidinium-phenol-chloroform method from the ahsv infected vero cells and was used as templates to optimize the rt-pcr. a pair of primer (np2-np32) amplified the product of the expe ...19948075225
the complete sequences of african horsesickness virus serotype 4 (vaccine strain) rna segment 2 and 6 which encode outer capsid protein.the complete sequences of rna segment 2 and segment 6 of african horsesickness virus serotype 4 (ahsv-4) vaccine strain were determined from cdna clones inserted into pbr 322. the rnas of segment 2 and 6 are 3229, 1566 bp long respectively and both contain an open reading frame encoding proteins vp2 and vp5 of 1060, 505 amino acid residues. the estimated molecular weight of vp2 was 124,178 dalton and that of vp5 was 56,793 dalton. their noncoding end sequences were 5'gtttaa . . . and . . . acata ...19948075221
identification of african horse sickness virus in cell culture using a digoxigenin-labeled rna probe.a digoxigenin-labeled rna probe was synthesized from a plasmid containing a portion of the african horse sickness virus (ahsv) serotype 4 genome segment coding for nonstructural protein 1. in an in situ hybridization procedure, this probe hybridized successfully to vero cells infected with each of the 9 serotypes of ahsv. there was no hybridization with noninfected cell cultures or cell cultures infected with bluetongue virus.19948068745
purification and properties of virus particles, infectious subviral particles, cores and vp7 crystals of african horsesickness virus serotype 9.methods were developed for the purification, at high yield, of four different particle types of african horsesickness virus serotype 9 (ahsv-9). these products included virus particles purified on cscl gradients which contain proteins apparently directly comparable to those of bluetongue virus (vp1 to vp7); virus particles purified on sucrose gradients which also contain, as a variable component, protein ns2; infectious subviral particles (isvps), containing chymotrypsin cleavage products of vp2 ...19948046387
expression and characterization of the two outer capsid proteins of african horsesickness virus: the role of vp2 in virus neutralization.african horsesickness virus (ahsv) is a gnat-transmitted member of the orbivirus genus of the reoviridae family. the virus has a genome of 10 double-stranded rna species (l1-l3, m4-m6, s7-s10). the l2 and m6 genes of ahsv serotype 4 (ahsv-4) which encode the outer capsid proteins vp2 and vp5, respectively, were inserted into recombinant baculoviruses downstream of the baculovirus polyhedrin, or p10 promoters. recombinant baculoviruses expressing vp2, vp5, or vp2 and vp5 proteins of ahsv-4 were i ...19948009847
rapid detection of african horsesickness virus by the reverse transcriptase polymerase chain reaction (rt-pcr) using the amplimer for segment 3 (vp3 gene).the complete sequence of the major core protein (vp3) gene of african horsesickness virus serotype 4 (ahsv-4; vaccine strain) was determined by analysis of a complete cdna clone representing segment 3. the rna was 2,789 bp long and a comparison of its sequence with that of bluetongue virus serotype 10 (btv-10) revealed 58% nucleotide similarity. based on these data, the reverse transcriptase-polymerase chain reaction (rt-pcr) technique was applied to the specific detection of ahsv using a pair o ...19948002793
diagnosis of african horsesickness.african horsesickness (ahs) is a very serious, non-contagious disease of horses and other solipeds caused by an arthropod-borne orbivirus of the family reoviridae. the epizootic nature of the disease makes rapid, accurate diagnosis of ahs absolutely essential. currently, diagnosis of ahs is based on typical clinical signs and lesions, a history consistent with vector transmission and confirmation by laboratory detection of virus and/or anti-ahs virus antibodies. the clinicopathologic presentatio ...19948001351
epizootiology and vectors of african horse sickness virus.african horse sickness (ahs) virus causes a non-contagious, infectious, arthropod-borne disease of equines and is enzootic in sub-saharan africa. the major vectors are species of culicoides but mosquitoes and ticks may be involved. periodically the virus makes excursions beyond its enzootic zones but until recently has not been able to maintain itself outside these areas for more than 2-3 consecutive years. this is probably due to a number of factors including the absence of a long term vertebra ...19948001350
african horse sickness virus structure.african horse sickness virus (ahsv), of which there are nine serotypes (ahsv-1, -2, etc.), is a member of orbivirus genus within the reoviridae family. both in morphology and molecular constituents ahsv particles are comparable to those of bluetongue virus (btv), the prototype virus of the genus. the two viruses have seven structural proteins (vp1-7) organized in two layered capsid. the outer capsid is composed of vp2 and vp5. the inner capsid, or core, is composed of two major proteins, vp3 and ...19948001348
cloning, characterization and expression of the gene that encodes the major neutralization-specific antigen of african horsesickness virus serotype 3.the gene encoding the outer capsid protein, vp2, of african horsesickness virus serotype 3 (ahsv-3) has been sequenced in its entirety from cdna clones of the segment 2 rna, and compared with the previously published vp2 gene sequence of ahsv-4. ahsv-3 genome segment 2 was shown to be 3221 nucleotides in length, encoding a protein of 1057 amino acids with a 50.5% identity to the amino acid sequence of ahsv-4 vp2. two areas of high variability (approximately 35% identity) were identified. the n-p ...19947996157
baculovirus expression of non-structural protein ns2 and core protein vp7 of african horsesickness virus serotype 3 and their use as antigens in an indirect elisa.non-structural protein ns2 and core protein vp7 of african horsesickness virus serotype 3 (ahsv3) were expressed in spodoptera frugiperda cells by recombinant baculoviruses containing the relevant genes. these proteins were purified and analysed by polyacrylamide gel electrophoresis and western blot. ns2 and vp7 were used separately as antigens in an indirect elisa for the detection of ahsv antibodies. both antigens cross-reacted with hyperimmune guinea-pig antisera to infected cell lysates of a ...19947989441
vaccinia virus expression of the vp7 protein of south african bluetongue virus serotype 4 and its use as an antigen in a capture elisa.recombinant vaccinia viruses expressing the vp7 core protein of south african bluetongue virus serotype 4 (sa-btv4) were identified by polymerase chain reaction amplification. expression of vp7 was verified by radio-immunoprecipitation and a f(ab')2-based elisa. antibodies to vp7 were detected in sera from sheep that had been infected with 20 different virulent btv serotypes by using the vaccinia virus (vv) expressed vp7 as antigen in a capture elisa. f(ab')2-immobilised vv-expressed sa-btv4 vp7 ...19947979976
phylogenetic analysis of segment 10 from african horsesickness virus and cognate genes from other orbiviruses.utilizing the reverse transcriptase-polymerase chain reaction (rt-pcr) procedure, we have synthesized full-length copies of segment 10 from african horsesickness virus (ahsv) serotypes 1, 4 and 8. the genes were cloned, sequenced and compared with the sequence of the cognate gene from ahsv serotypes 3 and 9. sequences were analyzed to assess evolutionary relationships among serotypes using cladistics. based on this analysis the data support a close relationship between serotypes 4 and 9 and betw ...19947975880
prevalence of antibodies against some equine viruses in zebra (zebra burchelli) in the kruger national park, 1991-1992.the presence of antibodies against equine encephalosis virus (eev) and equid herpesvirus 1 and 4 in zebra in the kruger national park (knp) was demonstrated. the ability of zebra to maintain immunity against eev is illustrated by the appearance of neutralizing antibodies in most zebra foals within months of losing their maternal immunity. this occurs in every month of the year, even in winter. the high proportion of serologically positive foals in winter is ascribed to the presence of large numb ...19937970572
presence of african horse sickness virus in equine tissues, as determined by in situ hybridization.in a retrospective study, a negative-sense digoxigenin-labeled rna probe, corresponding to the gene encoding nonstructural protein-1 of african horse sickness virus (ahsv) serotype 4, was applied to formalin-fixed, paraffin-embedded tissue taken from horses in the terminal stages of infection with ahsv. fifteen infected ponies and one noninfected control were studied. ponies exhibited a range of clinical signs and lesions. thirteen ponies were infected with serotype 4, one with serotype 1, and o ...19947863585
clinical pathology and hemostatic abnormalities in experimental african horsesickness.infection of naive north american horses with 10(4) cell culture infectious doses (ccid50) of virulence variants of african horsesickness virus (ahsv), designated ahsv/4sp, ahsv/9pi, and ahsv/4pi, reproduced three classical forms of african horsesickness: acute (pulmonary), subacute (cardiac), and febrile, respectively. distinct clinicopathologic and hemostatic abnormalities were associated with each form of disease. hemostatic abnormalities included increased concentration of fibrin degradation ...19957771050
the transmission and geographical spread of african horse sickness and bluetongue viruses.african horse sickness virus (ahsv) and bluetongue virus (btv) are dsrna viruses within the genus orbivirus. both are able to cause non-contagious, infectious arthropod-borne diseases in their respective vertebrate hosts. ahsv infects equines and occasionally dogs, whereas btv replicates in ruminants. the disease caused by ahsv is usually at its most severe in horses, whereas certain breeds of sheep are particularly sensitive to btv infection. ahsv is endemic in sub-saharan africa but periodical ...19957741589
expression of nonstructural protein ns3 of african horsesickness virus (ahsv): evidence for a cytotoxic effect of ns3 in insect cells, and characterization of the gene products in ahsv infected vero cells.the smallest genome segment of african horsesickness virus (ahsv), segment 10 (s10), encodes two minor nonstructural proteins, ns3 and ns3a. while the cognate bluetongue virus (btv) proteins have been suggested to play a role in the release of virus particles from infected cells, no function has yet been ascribed to ahsv ns3/ns3a. when the ahsv-3 s10 gene was expressed in a baculovirus system only a single ns3 protein (24 k) was synthesized, at lower levels than expected. it was shown that this ...19957710356
neutralizing epitopes of african horsesickness virus serotype 4 are located on vp2.a panel of monoclonal antibodies (mabs) was generated against african horsesickness virus serotype 4 (ahsv/4). three of the mabs (sa6, oh3, and me11) strongly neutralized the homologous virus and a heterologous type 4 isolate. the mabs did not cross-neutralize ahs serotypes 1-3 or 5-9. the mabs immunoprecipitated a viral protein of 108 kda which co-migrated with vp2. pretreatment with sa6 prevented mortality of 71% of day-old mice after intracranial injection of 100 ld50 of ahsv/4, while oh3 and ...19937690505
comparison of the non-structural protein, ns1, of tick-borne and insect-borne orbiviruses.the nucleotide sequence of rna segment 6 of broadhaven virus (brdv), a tick-borne orbivirus, was determined principally from two overlapping cdna clones and rna end sequence analysis. the genome segment is 1714 base pairs in length and has a coding capacity for a protein of 537 amino acids, having a net charge of +4.0 at neutral ph. comparison of the predicted amino acid sequence of brdv rna segment 6 with the ns1 sequence of insect-borne orbiviruses, bluetongue virus (btv), african horse sickne ...19957653106
african horsesickness epidemiology: five species of culicoides (diptera: ceratopogonidae) collected live behind the ears and at the dung of the african elephant in the kruger national park, south africa.during the culling of elephants (loxodonta africana) at five sites in the kruger national park, south africa, a total of 682 culicoides of five species of the subgenus avaritia were found live either behind the ears of elephants or attracted to the freshly disembowelled intestinal dung of elephants. the species are culicoides tororoensis khamala & kettle, 1971; c. kanagai khamala & kettle, 1971; c. loxodontis meiswinkel, 1992, and two undescribed species, i.e. culicoides sp. #50 and culicoides s ...19947596566
proteolytic cleavage of vp2, an outer capsid protein of african horse sickness virus, by species-specific serum proteases enhances infectivity in culicoides.purified african horse sickness virus (ahsv) was fed, as part of a blood meal, to adult females from a susceptible colony of culicoides variipennis, established in the insectories at the institute for animal health, pirbright laboratory, uk. the meal consisted of heparinized blood obtained from ovine, bovine, equine (horse and donkey) or canine sources spiked with ahsv serotype 9 (ahsv9). the infectivity levels observed for c. variipennis varied significantly, according to the source of the bloo ...19957595366
influence of antigen presentation and exogenous cytokine activity during in vitro primary immunizations employed for the generation of monoclonal antibodies.hybridomas secreting monoclonal antibodies (mabs) against african horse sickness virus (ahsv) were generated using different ahsv antigen preparations (inactivated ahsv, semi-purified virus, and a preparation of nonstructural viral proteins) in one of three different in vitro primary immunization systems: (i) the cel-prime kit, a method using immunization of splenocytes aided by antigen-primed support cells; (ii) a system based on a cytokine soup derived from a mixed lymphocyte reaction plus sti ...19957594620
application of the polymerase chain reaction to the detection of african horse sickness viruses.the development of a coupled reverse transcriptase-polymerase chain reaction assay (rt-pcr) is described for the detection of african horse sickness virus (ahsv) double-stranded rna. genome segments 7 and 10 were chosen as target templates for primers selected for use in the rt-pcr. using these ahsv-specific primers all 9 serotypes were detectable. the sensitivity and specificity of the rt-pcr results were compared to those obtained by competition elisa.19957543488
identification of a linear neutralization domain in the protein vp2 of african horse sickness virus.overlapping fragments of the outermost capsid protein vp2 of african horse sickness virus serotype 4 (ahsv-4) have been expressed in escherichia coli. horse sera from infected and vaccinated animals, rabbit sera, and mice monoclonal antibodies specific for ahsv were used to screen these fragments for antigenic regions. the screening revealed that the major antigenic domain of the ahsv-4 vp2 is localized in a central region (amino acids 200 to 413) and that both the n-terminal region (aa 1-159) a ...19957542417
the multimeric nonstructural ns2 proteins of bluetongue virus, african horsesickness virus, and epizootic hemorrhagic disease virus differ in their single-stranded rna-binding ability.the structure and single-stranded (ss) rna-binding by the nonstructural protein ns2 of three different orbiviruses were studied and compared. african horsesickness virus (ahsv), bluetongue virus (btv), and epizootic hemorrhagic disease virus (ehdv) were analyzed in recombinant baculovirus-infected cells and in cells infected with btv and ahsv. sedimentation analysis and nonreducing sds-page revealed that ns2 of all three orbiviruses is a 7s multimer with both inter- and intramolecular disulfide ...19957539971
epidemiology of african horsesickness: duration of viraemia in zebra (equus burchelli).the viraemic period of african horsesickness is significantly longer in experimentally infected zebra than in horses. the virus could be isolated 40 d post-infection from blood and 48 d post-infection from spleen. the introduction of zebra into african horsesickness-free countries should therefore be considered carefully, and preferably be restricted to serologically negative zebra.19947501371
the virtual absence of culicoides imicola (diptera: ceratopogonidae) in a light-trap survey of the colder, high-lying area of the eastern orange free state, south africa, and implications for the transmission of arboviruses.altogether 52 078 culicoides biting midges of 35 species were collected during february 1990 and 1993 in 40 light-trap collections made on 17 cattle and/or sheep farms in the bethlehem and fouriesburg districts of the colder, high-lying eastern orange free state. culicoides (avaritia) bolitinos was by far the most abundant species, representing 50.9% of all specimens collected. culicoides (a.) imicola, considered to be the most common stock-associated species in the summer rainfall areas of sout ...19947501364
sequences of e/ns1 gene junction from four dengue-2 viruses of northeastern thailand and their evolutionary relationships with other dengue-2 viruses.we determined the 240-nucleotide sequences of the e/ns1 gene junction of four dengue-2 viruses by the primer extension dideoxy chain termination method. these viruses were isolated from dengue patients with different clinical severities in nakhon phanom, northeastern thailand in 1993. the results were compared with the 52 published dengue-2 sequences of the same gene region. sequence divergence of four new isolates varied from 4.17% to 5.42% compared with dengue-2 prototype new guinea c strain w ...19957494497
detection of african horse sickness viruses by dot-blot hybridization using a digoxigenin-labelled probe.in order to develop a non-radioactive dot-blot hybridization assay, for the detection of african-horse sickness virus (ahsv), genome segment 7 from 9 serotypes was amplified by rt-pcr. the resulting pcr products were denatured, immobilized on nylon membranes and then hybridized to a non-radioactive digoxigenin-labelled probe. this probe (265 bp in length) was generated by nested-pcr using genome segment 7 of ahsv, serotype 4 as a template. the dot-blot was visualized by chemiluminescence. positi ...19957477018
the role played by hyalomma dromedarii in the transmission of african horse sickness virus in egypt. 19817348587
an outbreak of african horsesickness in dogs.several dogs died from african horsesickness which was contracted by the consumption of uncooked meat from the carcase of a horse that had died from the disease. respiratory embarrassment was the main clinical sign, while marked hydrothorax and pulmonary congestion and oedema were the major post mortem findings. serotype 6 horsesickness virus was isolated from 2 of these dogs.19817341783
isolation and identification of african horsesickness virus from naturally infected dogs in upper egypt.african horsesickness virus was isolated from blood samples of street dogs in aswan province in arab republic of egypt. of six isolated "dog strain" african horsesickness viruses, three viruses designated d2, d6 and d10 have been identified as type 9 african horsesickness virus. methods of isolation, tissue culture adaptation, serological indentification and typing are described. horses experimentally infected with dog viruses showed febrile reaction and characteristic clinical and pathological ...19817337871
persistence of african horse sickness in nigeria. 19817292615
the incidence of african horse sickness antibodies in animals of various species in egypt. 19817201860
factors associated with improved haemagglutination by african horse sickness virus. 19827112896
the effect of temperature on the in vitro transcriptase reaction of bluetongue virus, epizootic haemorrhagic disease virus and african horsesickness virus.virions of bluetongue virus (btv), epizootic haemorrhagic disease virus (ehdv) and african horsesickness virus (ahsv) can be converted to core particles by treatment with chymotrypsin and magnesium. the conversion is characterized by the removal of the 2 outer capsid polypeptides of the virion. the loss of these 2 proteins results in an increase in density from 1,36 g/ml to 1,40 g/ml on cscl gradients. the btv, ehdv and ahsv core particles have an associated double-stranded rna dependent rna tra ...19826308533
antibody titres to african horse sickness, swine vesicular disease and foot-and-mouth disease viruses in samples from equidae in malta, 1975. 19826284298
infection of israeli culicoides with african horse sickness, blue tongue and akabane viruses.type 9 african horse sickness virus and type 4 bluetongue virus multiplied to a high titre in an israeli strain of culicoides puncticollis after intrathoracic inoculation. akabane virus persisted for at least 10 days in this midge after intrathoracic inoculation but with little evidence of virus multiplication. all 3 viruses failed to multiply in c. puncticollis after ingestion by the oral route and all were inactivated by 4 days post infection. five other species of israeli culicoides supported ...19816120643
inactivated african horse sickness virus cell culture vaccine. 19685635756
the nucleic acid of african horse sickness virus. 19665223428
isolation and identification of african horse-sickness virus in nigeria. 19715105172
plaque formation by african horsesickness virus and characterization of its rna. 19705005083
intracellular inclusions resulting from infection with african horsesickness virus.intranuclear and intracytoplasmic inclusions in monkey kidney cells infected with african horsesickness virus were studied with the aid of electron microscopy.19694980070
electron microscopic characterization of african horse-sickness virus. 19694978807
quantitative studies on the neutralization reaction between african horse-sickness virus and antiserum. 19684977764
effects of freezing on african horse-sickness virus. 19684974541
electron microscopic study of the formation of african horse-sickness virus. 19674971395
thermal stability of african horse sickness virus. 19674970516
cytochemical studies with african horse sickness virus by fluorescent microscopy. 19674970515
buoyant density of african horsesickness virus. 19674964239
some properties of avirulent cold variants of african horse sickness virus. 19674962856
sequential cellular changes produced by african horse-sickness virus in monkey kidney cells. 19664959956
development of plaque techniques for titration and neutralization tests with african horse-sickness virus. 19664958049
cytology of monkey kidney cells infected with african horse-sickness virus. 19654953803
studies on the properties of african horse-sickness virus. 19684871753
the isolation and identification of type 9 african horse sickness virus in the sudan. 19744447879
african horse sickness virus antibodies in cyprus--1971-72. 19744428592
detection of african horsesickness viral antigens in tissues by immunofluorescence.the fluorescent antibody reaction was studied in tissues of ponies infected with african horsesickness virus (ahsv). lung, spleen, lymph node, liver, skeletal muscle, intestine, stomach, nerve ganglion and kidney were sectioned and stained by the direct fluorescent antibody technique (fa). fluorescence was demonstrated only in the spleen and could be inhibited by using unconjugated antiserum.19724259931
studies on the replication of african horse-sickness virus in two different cell line cultures. 19674232530
characterization of african horsesickness virus. 19704193496
growth and persistent infection of african horse-sickness virus in a mosquito cell line. 19704097067
role of culex pipiens l. in recovering latent african-horse-sickness virus from dogs. 19863722893
a single dilution enzyme-linked immunosorbent assay for the quantitative detection of antibodies to african horsesickness virus.a single dilution enzyme-linked immunosorbent assay (elisa), utilizing a reference serum with a known, predetermined end-titre was used to compute antibody titres of serum samples against african horsesickness virus. compared to the complement fixation test it was found to be highly reproducible and sensitive. the assay also reduced the effect of between-test variations on test results and proved superior to an existing single-dilution elisa method.19873587930
[various aspects of horse sickness].the aetiology, symptoms, diagnosis and control of african horse sickness are described. special attention is paid to the introduction and epizootiology of the disease in spain and its consequences in respect to the international trade of horses.19883413759
observations on antibody levels associated with active and passive immunity to african horse sickness.tests for neutralising (nt) antibodies to the nine serotypes of african horse sickness (ahs) virus on the sera of three groups of horses confirmed that an increasing number of immunisations with vaccine containing attenuated strains of serotypes 1 to 6 of the virus, leads to broader response to the various serotypes and to higher individual titres. nevertheless some horses failed to respond to one or more serotypes despite receiving numerous immunisations and it was clear that vaccine containing ...19883238767
african horse sickness in zimbabwe: 1972 to 1981.during the nine years from october 1972 to september 1981 african horse sickness (ahs) virus was isolated from 23 suspected cases of the disease in zimbabwe and complement fixation antibody titres indicative of recent infection were detected in a further 49 horses. the 23 isolations belonged to seven of the nine known serotypes of ahs virus. in response to a questionnaire in 1980 the owners of 20% (1,654/8,000) of the horses in zimbabwe indicated that they had recorded 207 cases of clinically di ...19883194977
sequence analyses of herpesviral enzymes suggest an ancient origin for human sexual behavior.comparison of the amino acid sequences of the deoxythymidine kinases of herpes simplex (hsv) and of marmoset herpes viruses (mhv) suggests a divergence time of 8 to 10 million years ago for hsv-1 and -2. like mhv, hsv-1 and -2 cause local infections in their natural hosts, and direct contact between two individuals during the brief period of infectivity is needed for transmission. because b virus, a nearer relative of hsv, depends on both oral and genital routes of transmission, we postulate tha ...19883128793
gamma ray sensitivity of bluetongue, ehd and african horsesickness viruses and their precipitating and complement fixing antigens. 19852989879
bluetongue and related orbiviruses: overview of the world situation.bt is silently spreading in tropical and subtropical countries in the world. serological surveys on bt in developing countries should be intensified and expanded. research is needed to develop simplified virus typing techniques, to develop safe and effective vaccines and to establish procedures for differentiating btv which produces clinical disease from that of low-virulency. it is considered necessary to develop a new disease reporting system which can accommodate both clinical and sub-clinica ...19852989847
characterization of a nonstructural phosphoprotein of two orbiviruses.a phosphorylated nonstructural protein, ns2, was detected in bluetongue and african horsesickness virus (btv and ahsv) infected-radiolabeled-cell lysates by electrophoresis on sds-polyacrylamide gels (sds-page). the ns2 proteins of both viruses have similar migration on one-dimensional (1d) 10% sds-page. examination of infected cell lysates on two-dimensional (2d) gels (isoelectric focusing followed by sds-page) separated two phosphorylated isoelectric forms of btv ns2 and four phosphorylated fo ...19882849253
the characterization of equine encephalosis virus and the development of genomic probes.equine encephalosis virus (eev) is an orbivirus associated with a peracute illness of horses in southern africa. the virus has now been partially purified for the first time and characterized on a molecular level. the virion is composed of 10 dsrna segments and a protein capsid consisting of at least seven structural proteins that vary in mr from 36,000 to 120,000. partial clones of six of the dsrna segments of eev serotype cascara were obtained and analysed for possible use as serotype-specific ...19892549180
characterization and cloning of the african horsesickness virus genome.the dsrna profiles of all nine african horsesickness virus (ahsv) serotypes were compared by agarose gel electrophoresis and page. the agarose profiles were identical, but a unique profile was obtained for each of the nine serotypes by page. nine of the 10 dsrna genome segments of ahsv-3 were cloned and the clones were used in dot-spot and northern blot hybridization experiments to determine intra- and inter-serogroup nucleic acid similarities. segments 1, 3, 4, 5, 7 and 8 were highly conserved ...19902324709
an indirect sandwich elisa utilising f(ab')2 fragments for the detection of african horsesickness virus.african horsesickness virus (ahsv), an important disease of equines is caused by an orbivirus. because of the need to contain the spread of the disease, it is often essential to make a rapid diagnosis. for this purpose, an elisa capable of detecting viral antigen in animal tissue and in cell culture fluid was developed. immobilised f(ab')2 fragments prepared by digestion of ahsv-specific igg with pepsin were used to trap virus from tissue homogenates or cell culture supernatant. after addition o ...19902266146
isolations of african horse sickness virus from vector insects made during the 1988 epizootic in spain.this paper describes the first isolations of african horse sickness virus (ahsv) from insects in spain. seven isolations of ahsv serotype 4 were made; four from culicoides imicola a known vector of the virus elsewhere, two from mixed pools of culicoides species not including c. imicola and one from blood engorged mosquitoes. three further isolations of ahsv serotype 4 were also made from horses kept adjacent to the insect collecting sites. this work presents the first definitive identification o ...19902209746
purification and characterization of the major group-specific core antigen vp7 of bluetongue virus synthesized by a recombinant baculovirus.the major core protein, vp7, of bluetongue virus serotype 10 (btv-10) has been purified from insect cells infected with a genetically manipulated recombinant baculovirus. the high level expression of vp7 (in excess of 100 mg per litre of culture) and its presence in the soluble fraction of infected cells following lysis by detergent has allowed the purification of the protein virtually to homogeneity (95%) by a simple two-step procedure of ammonium sulphate fractionation and ion-exchange chromat ...19902174958
laboratory diagnosis of african horse sickness: comparison of serological techniques and evaluation of storage methods of samples for virus isolation.five serological methods of diagnosing african horse sickness were evaluated, using a battery of serum samples from experimental horses vaccinated and challenged with each serotype of african horse sickness virus (ahsv1 through ahsv9): agar gel immunodiffusion (agid), indirect fluorescent antibody (ifa), complement fixation (cf), virus neutralization (vn), and enzyme-linked immunosorbent assay (elisa). the 5 tests were also compared using a panel of field samples, convalescent equine sera with a ...19902128615
african horse sickness in saudi arabia. 19902118696
a competitive elisa for the detection of group-specific antibodies to african horse sickness virus.a competition enzyme-linked immunosorbent assay (elisa) has been developed for the rapid identification and quantification of antibodies against african horse sickness (ahs) in sera from solipeds. the data showed the elisa to be sensitive, specific and reliable. more than 1600 sera from 37 different countries were examined and results compared with those obtained by agar gel immuno-diffusion (agid) tests. in no case did any of 775 sera from countries where ahs has never been reported and where a ...19902108871
laboratory confirmation of african horsesickness in the western cape: application of a f(ab')2-based indirect elisa.recently a suspected outbreak of african horsesickness in the western cape province resulted in the deaths of four foals and one adult horse. spleen samples from these animals were subjected to analysis by an enzyme-linked immunosorbent assay (elisa) which uses f(ab')2 fragments of immunoglobulins to detect african horse sickness virus (ahsv) antigens. the results of the immunoassay were compared with those obtained by isolation followed by serotyping as is currently applied by the reference cen ...19912052314
a comparison of the genes which encode non-structural protein ns3 of different orbiviruses.the segment 10 (s10) genes of african horsesickness virus (ahsv), palyam virus and epizootic haemorrhagic disease virus were translated in vitro in a rabbit reticulocyte lysate system. each of the s10 genes encoded two proteins ns3 and ns3a, which were shown to be related by peptide mapping. cloned copies of the s10 genes of two ahsv serotypes (ahsv-3 and ahsv-9) and palyam virus were sequenced and compared to each other and to the nucleotide sequence of bluetongue virus (btv) gene s10. two in-p ...19912033391
antibodies in horses, mules and donkeys following monovalent vaccination against african horse sickness.a total of 256 sera collected from three species of domesticated equidae in four different spanish provinces were examined 1-4 months after the administration of attenuated monovalent african horse sickness virus (ahsv) serotype 4 vaccine. approximately 10% of the sera were negative by elisa, virus neutralization, agar gel immuno-diffusion and complement fixation tests. similar negative reactions were recorded with sera from two ponies after experimental primary vaccination. the rapid rise in an ...19911902185
a serogroup specific enzyme-linked immunosorbent assay for the detection and identification of african horse sickness viruses.a serogroup specific, indirect, sandwich elisa was developed for the rapid detection of african horse sickness virus and viral antigens in field samples or in infected tissue cultures. the assay was shown to be highly sensitive and capable of providing confirmation of clinical diagnosis within one day. the results demonstrated that this elisa will be useful for epidemiological surveillance of insect and mammalian host populations.19911864909
the use of elisa for the detection of african horse sickness viruses in culicoides midges.the use of elisa for the detection of african horse sickness viruses (ahsv) in midges preserved in 5.0% formalin was evaluated. no differences were detected by elisa when testing ahsv infected batches of culicoides midges collected in diluent with or without the addition of formalin. the elisa was considered highly sensitive and easily distinguished between non-infected midges and batches containing varying numbers of infected and non-infected midges. positive elisa reactions were detected with ...19911804852
vp2 is the major exposed protein on orbiviruses. 19911759907
a comparison of the nucleotide sequences of cognate ns2 genes of three different orbiviruses.the genes encoding nonstructural protein ns2 of african horsesickness virus (ahsv) and epizootic hemorrhagic disease virus (ehdv) were cloned, sequenced, and compared to the ns2 gene of bluetongue virus (btv). nucleotide similarity ranged from 53 to 60%. the length of the proteins varied from 376 amino acids (ehdv) to 365 amino acids (ahsv). the n-terminal half of ns2 is more conserved (+/- 58% similarity) among the three orbiviruses, while the c-terminal half contains a 120 amino acid region of ...19911656603
the use of a membrane feeding technique to determine the infection rate of culicoides imicola (diptera, ceratopogonidae) for 2 bluetongue virus serotypes in south africa.culicoides spp. in the lowveld of the northern transvaal, republic of south africa, were fed bluetongue virus serotypes 3 and 6 and african horsesickness virus serotype 1 through latex and chicken skin membranes. after an incubation period of 10 days at 25-27 degrees c, the infection rate of c. imicola for bluetongue virus serotypes 3 and 6 was established at 31% and 24% respectively. no african horsesickness virus could be recovered. the membrane feeding technique and handling procedures proved ...19911646980
the complete sequence of the group-specific antigen, vp7, of african horsesickness disease virus serotype 4 reveals a close relationship to bluetongue virus.the complete sequence of the s7 rna that codes for the major group-specific coat protein. vp7, of african horsesickness virus serotype 4 (ahsv-4) was determined from cdna analyses and found to be 1179 nucleotides in length. one single open reading frame of 353 codons was observed defining a protein of mr 38,107 with a net charge of -1.5 at neutral ph. comparison of the ahsv-4 vp7 sequence with that of bluetongue virus serotype 10 revealed an overall similarity of 44%, with the amino- and carboxy ...19911646273
a review of african horse sickness with emphasis on selected vaccines. 19921626876
an attempt to define the host range for african horse sickness virus (orbivirus, reoviridae) in east africa, by a serological survey in some equidae, camelidae, loxodontidae and carnivore.a survey was carried out in horse, zebra, elephant, camel, sheep and goat and wild carnivore sera for virus-serum neutralising antibody to the nine type strains of african horse sickness virus. antibody was found amongst the horse, zebra and elephant sera to all nine different strains. no antibody was detected in any sera from camels, sheep and goats. none was found in sera from hyaena and jackals in this series but had been detected earlier.19921615634
encephalitis and chorioretinitis associated with neurotropic african horsesickness virus infection in laboratory workers. part iv. experimental infection of the vervet monkey (cercopithecus pygerythrus).neurotropic vaccine strains of african horsesickness (ahs) virus types 1 and 6 were implicated as the possible aetiological agents in 4 cases of encephalitis and uveochorioretinitis in laboratory workers accidentally exposed to the freeze-dried vaccine preparations of the virus. to date, ahs virus has not been known to infect man. to ascertain whether or not primates were susceptible to infection with ahs virus, vervet monkeys (cercopithecus pygerythrus) were inoculated, either transnasally or i ...19921574749
encephalitis and chorioretinitis associated with neurotropic african horsesickness virus infection in laboratory workers. part iii. virological and serological investigations.four cases of encephalitis with chorioretinitis occurred in the vaccine-packing section of a veterinary research institute: 1 in 1982, 1 in 1985 and 2 in 1989. no viruses were isolated from patients and serological tests failed to reveal significant antibodies to a range of viruses incorporated in veterinary vaccines or to other likely pathogens, except for low titres of complement-fixing antibody to african horsesickness (ahs) virus in all 4 patients. in confirmatory tests, high enzyme immunoas ...19921574748
encephalitis and chorioretinitis associated with neurotropic african horsesickness virus infection in laboratory workers. part ii. ophthalmological findings.four laboratory workers developed uveitis-chorioretinitis, associated with encephalitis in 3 cases. the retinitis was characterised by haemorrhages and areas of retinal oedema, most marked over the posterior polar regions, and was associated with exudative retinal detachments. the lesions progressed over weeks and showed a severe retinal arterial vasculopathy with arteriolar narrowing, ghost vessel formation and the development of optic atrophy. the picture in 2 of the patients resembled that of ...19921574747
encephalitis and chorioretinitis associated with neurotropic african horsesickness virus infection in laboratory workers. part i. clinical and neurological observations.four laboratory workers from the same vaccine-packing facility developed at different times over an 8-year period an illness characterised by encephalitis (in 3 workers) and uveochorioretinitis (in 4). low complement fixation titres were detected in all 4 patients to african horsesickness (ahs) virus and enzyme immunoassay and plaque reduction neutralising tests were positive, the latter against both serotypes 1 and 6. five of 15 laboratory workers from the same facility who were healthy on clin ...19921574746
the detection of african horse sickness virus antigens and antibodies in young equidae.four ponies were each inoculated with a different serotype of african horse sickness virus (ahsv) which had been passaged through cell culture in order to achieve attenuation. three of the ponies died suddenly after showing mild clinical signs, the fourth pony remained clinically normal and was killed at day 38. infectious ahsv was isolated from blood samples collected at intervals from all four ponies. positive antigen elisa reactions were only observed with blood samples from two of the ponies ...19921547837
identification and characterization of the structural and nonstructural proteins of african horsesickness virus and determination of the genome coding assignments.proteins present in purified african horsesickness virus (ahsv) and in infected cells were analyzed by sds-polyacrylamide gel electrophoresis. twelve viral proteins were identified, one minor and four major structural proteins, three major and two minor nonstructural proteins, as well as variable amounts of two additional structural proteins. cell-free translation of total ahs virion rna in a rabbit reticulocyte system resulted in the synthesis of proteins which were qualitatively and quantitati ...19921531096
Displaying items 301 - 400 of 424