Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| molecular epidemiology of african horse sickness virus based on analyses and comparisons of genome segments 7 and 10. | this paper describes a method to rapidly identify african horse sickness virus (ahsv), using a single tube reverse transcription polymerase chain reaction (pcr). this method was used to amplify cdna copies of genome segments 7 and 10 from several different ahsv strains, of different serotypes, which were then analysed by sequencing and/or endonuclease digestion. ahsv vp7 (encoded by genome segment 7) is one of the two major capsid proteins of the inner capsid layer, forming the outer surface of ... | 1998 | 9785509 |
| structural studies of orbivirus particles. | we are using crystallographic methods to investigate the structure of ahsv and btv. our initial approach was to investigate the structure of the major protein component of the viral core, vp7(t13). this trimeric protein has been studied in several crystal forms from both orbiviruses and reveals a structure made up of conserved domains, capable of conformational changes and possessing a cleavage site. further crystallographic analyses of native particles have provided a picture of the vp7(t13) an ... | 1998 | 9785510 |
| validation of elisa for the detection of african horse sickness virus antigens and antibodies. | the mortality rate in susceptible populations of horses during an epizootic of african horse sickness (ahs) may be in excess of 90%. rapid and reliable assays are therefore essential for the confirmation of clinical diagnoses and to enable control strategies to be implemented without undue delay. one of the major objectives of a recent european union funded project was the validation of newly developed diagnostic assays which are rapid, sensitive, highly reproducible and inexpensive, for the det ... | 1998 | 9785516 |
| use of reverse transcriptase-polymerase chain reaction (rt-pcr) and dot-blot hybridisation for the detection and identification of african horse sickness virus nucleic acids. | a coupled reverse transcriptase-polymerase chain reaction assay (rt-pcr) for the detection of african horse sickness virus (ahsv) dsrna, has been developed using genome segment 7 as the target template for primers. rna from isolates of all nine ahsv serotypes were readily detected. the potential inhibitory effects of either ethylene diamine tetra acetic acid (edta) or heparin on the rt-pcr were eliminated by washing blood samples before lysis of the red blood cells and storage. there was a close ... | 1998 | 9785517 |
| intracellular production of african horsesickness virus core-like particles by expression of the two major core proteins, vp3 and vp7, in insect cells. | to gain more insight into the structure of the african horsesickness virus (ahsv) core particle, we have cloned, partially characterized and expressed the two major core proteins, vp3 and vp7, of ahsv-9. vp7 was found to be highly conserved amongst different serotypes. the vp3 and vp7 genes were subsequently expressed in insect cells by means of recombinant baculoviruses. vp7 was synthesized to very high levels and aggregated into distinctive crystals. co-expression of vp3 and vp7 resulted in th ... | 1998 | 9472617 |
| sequence analysis of the rna polymerase gene of african horse sickness virus. | the gene encoding the inner core protein vp1 of african horse sickness virus (ahsv) serotype 9 has been cloned, expressed in vitro and entirely sequenced, completing molecular characterization of the ahsv genome. an analysis of the sequence supporting the identity of ahsv vp1 as the putative viral rna polymerase is presented. | 1998 | 9541625 |
| taxonomy of african horse sickness viruses. | nine distinct genera are currently recognised within the virus family reoviridae, which include a total of 63 virus groups or species (species = virus group = electropherotype or serogroup), comprising 214 virus serotypes or subtypes, as well as 20 provisional types or subtypes, most of which (149 + 9 tentative) are assigned to the genus orbivirus [5, 9, 16]. the 19 species of orbiviruses (serogroups), were established principally on antigenic (serologic) grounds but many of these placements hav ... | 1998 | 9785490 |
| epidemiology of african horse sickness and the role of the zebra in south africa. | zebra are the only equine species native to south africa. these animals roamed over much of the country in the 17th century when horses and donkeys were first imported. the first cases of african horse sickness (ahs) then occurred in the horses of hunters who entered zebra territory. ahs continued to occur on a country-wide basis until the beginning of the 20th century, though the number of outbreaks decreased as the populations of zebra collapsed through overhunting. for most of the 20th centur ... | 1998 | 9785491 |
| protein aggregation complicates the development of baculovirus-expressed african horsesickness virus serotype 5 vp2 subunit vaccines. | this paper describes the expression of a cloned african horsesickness virus (ahsv) serotype 5 vp2-gene by a baculovirus recombinant that was generated by the bac-to-bac system. immunization of horses with crude cell lysates containing recombinant baculovirus-expressed ahsv5 vp2 did induce neutralizing antibodies, but afforded only partial protection against virulent virus challenge. further analysis of partially protective crude cell lysates revealed that baculovirus-expressed ahsv5 vp2 was pred ... | 1998 | 10192846 |
| effect of temperature on african horse sickness virus infection in culicoides. | this paper shows that both the infection rate and the rate of virogenesis of african horse sickness virus (ahsv) within vector culicoides are temperature dependent. as temperature is reduced from permissive levels the lifespan of the vector itself is extended but the rate of virogenesis decreases and infection rate falls dramatically so that at 10 degrees c virtually all midges are free from virus by 13 days post infection (dpi). when vectors that had been kept at this temperature for 35 days we ... | 1998 | 9785504 |
| characterization of two african horse sickness virus nonstructural proteins, ns1 and ns3. | each of the ten segments of the african horse sickness virus (ahsv) genome encodes at least one viral polypeptide. this report focuses on the nonstructural proteins ns1 and ns3, which are encoded by genome segments 5 and 10 respectively. the ns1 protein assembles into tubular structures, which are characteristically produced during orbivirus replication in infected cells. ns1 expressed by a recombinant baculovirus in sf9 cells also forms tubules, which were analysed electron microscopically. the ... | 1998 | 9785511 |
| development of a mouse model system, coding assignments and identification of the genome segments controlling virulence of african horse sickness virus serotypes 3 and 8. | attenuated (att) and wild type (wt) strains of the nine ahsv serotypes were evaluated for virulence in adult balb c mice. although most were avirulent in this system, isolates of ahsv 1att, 3wt, 3att, 4wt, 5att, 7att and 8att caused some mortality when administered via an intranasal route. after plaque cloning, only the attenuated vaccine strain of ahsv 7att caused any mortality via an intravenous route. ahsv 3att and ahsv 8wt were virulent (v) and avirulent (av) (respectively) in the mouse mode ... | 1998 | 9785512 |
| phylogenetic analysis of african horse sickness virus segment 10: sequence variation, virulence characteristics and cell exit. | african horse sickness virus (ahsv) genome segment 10 encodes the non-structural proteins ns3/ns3a, which is involved in release of virus from cells. full length segment 10 cdnas were amplified by reverse transcription-polymerase chain reaction, from isolates of ahsv serotypes 2, 3, 4, 5, 7, 8 and 9. these cdnas were cloned, sequenced and their phylogenetic relationships analysed. high levels of sequence homology were detected in segment 10 from some isolates of different serotypes, confirming t ... | 1998 | 9785513 |
| future international management of african horse sickness vaccines. | three types of african horse sickness (ahs) vaccine, namely adult mouse brain, modified live vaccine and inactivated viral vaccine (ivv) are reviewed. the results of efficacy trials carried out with each vaccine type highlight the advantages of the ivv. vaccination with african horse sickness virus serotype 4 ivv, given as 2 separate doses, provided full protection against subsequent, homologous challenge. the absence of any detectable viraemia after challenge would also prevent infection of ins ... | 1998 | 9785514 |
| application of an indirect fluorescent antibody assay for the detection of african horse sickness virus antibodies. | an indirect fluorescent antibody (ifa) technique was used to screen and quantify antibodies against african horse sickness virus (ahsv) in equine sera. results obtained with the ifa assay were compared directly with those obtained with standard complement fixation (cf) and virus neutralisation (vn) tests using horse sera from experimental studies and samples from the field. positive fluorescent antibody titres were detected from as early as 7 days after primary vaccination and persisted for at l ... | 1998 | 9785515 |
| the culicoides vectors of african horse sickness virus in morocco: distribution and epidemiological implications. | african horse sickness (ahs) is a vector-borne, infectious disease of equids caused by african horse sickness virus. the only proven field vector of the virus is the biting midge culicoides imicola, although c. obsoletus and c. pulicaris are suspected vectors. in 1994-5 a total of 3887 light trap samples were collected from 22 sites distributed over most of morocco. culicoides imicola was found to be very widely distributed with the greatest catches in the low-lying north-western areas (between ... | 1998 | 9785501 |
| studies of the mortality rate of culicoides imicola in morocco. | daily mortality rates of female culicoides imicola were found for eight sites in morocco in 1994 and for six sites in 1995. the mortality rates were found by operating pirbright-type light traps for a number of consecutive nights in late summer or autumn and finding the parous rate assuming a feeding interval of 3 to 5 days. the mortality rates were calculated according to established methods. in morocco the daily mortality rates were found to vary from about 5% per day (arbaoua, 1994, 1995 and ... | 1998 | 9785502 |
| the use of chicken igy in a double antibody sandwich elisa for detecting african horsesickness virus. | an indirect sandwich elisa that can detect as little as 8 ng of african horsesickness virus (ahsv) was developed. viral antigen was captured from suspension using an immobilized monoclonal antibody specific for an epitope on vp7, a protein that is a major constituent of the virus core. egg-yolk derived chicken igy directed against ahsv (serotype 3) was used as the secondary antibody. since igy and mouse igg do not cross-react serologically, the secondary antibody was not labelled, but was instea ... | 1999 | 10396758 |
| immune responses in a horse inoculated with the vp2 gene of african horsesickness virus. | the ability of a dna vaccine to elicit an immune response in a horse was evaluated. the outer capsid protein vp2 of african horsesickness virus is known to elicit protective immunity in horses. reverse transcribed dna of the gene encoding vp2 was placed under the transcriptional control of the cytomegalovirus immediate-early enhancer/promoter and was injected on several occasions intramuscularly into a horse. low antibody levels could be detected by elisa. antibodies directed against vp2 alone w ... | 1999 | 10486832 |
| vector competence of selected south african culicoides species for the bryanston serotype of equine encephalosis virus. | equine encephalosis virus (eev) was recognized and described in the republic of south africa in 1967 and subsequent serological studies have shown this orbivirus to be both widespread and prevalent in southern africa. in the present study it was shown that wild-caught culicoides (avaritia) imicola kieffer (diptera: ceratopogonidae) can become infected with and permit the replication of the bryanston serotype of eev following membrane-feeding on infective blood containing 5.0 log10 plaque-forming ... | 1999 | 10608228 |
| african horse sickness in portugal: a successful eradication programme. | african horse sickness (ahs) was diagnosed for the first time in southern portugal in autumn 1989, following outbreaks in spain. ahs virus presence was confirmed by virus isolation and serotyping. an eradication campaign with four sanitary zones was set up by central veterinary services in close collaboration with private organizations. vaccination began on 6 october. in february 1990, vaccination was extended to all portuguese equines (170000 animals). there were 137 outbreaks on 104 farms: 206 ... | 1999 | 10579455 |
| [use of the immunoenzyme test elisa-ns3 to distinguish horses infected by african horsesickness virus from vaccinated horses]. | a vaccination protocol involving three horses, with five repeated injections of inactivated serotype 4 african horse sickness virus, was undertaken to determine a possible threshold for the appearance of antibodies against the non-structural protein ns3. using an indirect enzyme-linked immunosorbent assay, with the recombinant ns3 protein as an antigen, the authors detected a response to ns3 as of the second injection for the first horse and after four injections for the second horse. no respons ... | 1999 | 10588005 |
| antigenic profile of african horse sickness virus serotype 4 vp5 and identification of a neutralizing epitope shared with bluetongue virus and epizootic hemorrhagic disease virus. | african horse sickness virus (ahsv) causes a fatal disease in horses. the virus capsid is composed of a double protein layer, the outermost of which is formed by two proteins: vp2 and vp5. vp2 is known to determine the serotype of the virus and to contain the neutralizing epitopes. the biological function of vp5, the other component of the capsid, is unknown. in this report, ahsv vp5, expressed in insect cells alone or together with vp2, was able to induce ahsv-specific neutralizing antibodies. ... | 1999 | 10329555 |
| molecular analysis of the genome of chuzan virus, a member of the palyam serogroup viruses, and its phylogenetic relationships to other orbiviruses. | the nucleotide sequence of the entire genome of chuzan virus, which belongs to the palyam serogroup orbiviruses and causes congenital abnormalities of cattle, has been completed by analysis of the genes encoding minor core proteins (vp1, vp4 and vp6) and non-structural proteins (ns1, ns2 and ns3). the genome of chuzan virus is 18,915 bp in length and the coding capacity of its open reading frames is 6071 aa. comparative sequence analysis with other serogroups of the genus orbivirus indicated tha ... | 1999 | 10211963 |
| molecular characterization of double-stranded rna segments encoding the major capsid proteins of a palyam serogroup orbivirus that caused an epizootic of congenital abnormalities in cattle. | cdna cloning of the double-stranded rna genome of chuzan virus, a member of the palyam serogroup orbiviruses, was carried out and the complete nucleotide sequences of rna segments 2, 3, 6 and 7, encoding the major capsid proteins vp2, vp3, vp5 and vp7, respectively, were determined. the individual segments had single open reading frames and short inverted repeats adjacent to the conserved terminal sequences. comparative sequence analysis with other serogroups of the genus orbivirus suggested tha ... | 1999 | 9934703 |
| identification and differentiation of the nine african horse sickness virus serotypes by rt-pcr amplification of the serotype-specific genome segment 2. | this paper describes the first rt-pcr for discrimination of the nine african horse sickness virus (ahsv) serotypes. nine pairs of primers were designed, each being specific for one ahsv serotype. the rt-pcr was sensitive and specific, providing serotyping within 24 h. perfect agreement was recorded between the rt-pcr and virus neutralization for a coded panel of 56 ahsv reference strains and field isolates. serotyping was achieved successfully with live and formalin-inactivated ahsvs, with isola ... | 2000 | 10675421 |
| effects of chlorine, iodine, and quaternary ammonium compound disinfectants on several exotic disease viruses. | the effects of three representative disinfectants, chlorine (sodium hypochlorite), iodine (potassium tetraglicine triiodide), and quaternary ammonium compound (didecyldimethylammonium chloride), on several exotic disease viruses were examined. the viruses used were four enveloped viruses (vesicular stomatitis virus, african swine fever virus, equine viral arteritis virus, and porcine reproductive and respiratory syndrome virus) and two non-enveloped viruses (swine vesicular disease virus (svdv) ... | 2000 | 10676896 |
| african horse sickness in senegal: serotype identification and nucleotide sequence determination of segment s10 by rt-pcr. | 2000 | 10682696 | |
| phylogenetic relationships of bluetongue viruses based on gene s7. | previous phylogenetic analyses based on bluetongue virus (btv) gene segment l3, which encodes the inner core protein, vp3, indicated a geographical distribution of different genotypes. the inner core protein, vp7, of btv has been identified as a viral attachment protein for insect cell infection. because the inner core proteins are involved with infectivity of insect cells, we hypothesized that certain vp7 protein sequences are preferred by the insect vector species present in specific geographi ... | 2000 | 10867193 |
| effect of mouse strain and age on detection of mouse parvovirus 1 by use of serologic testing and polymerase chain reaction analysis. | detection of mouse parvovirus 1 (mpv) depends on use of serologic and polymerase chain reaction (pcr) assays. these assays were evaluated for their ability to detect virus-specific antibodies or viral dna in multiple strains and ages of mice inoculated with mpv. | 2000 | 11099132 |
| cloning, sequencing and expression of the gene that encodes the major neutralisation-specific antigen of african horsesickness virus serotype 9. | a marked improvement in the efficiency of cloning the large double stranded rna (dsrna) genome segments of african horsesickness virus (ahsv) was achieved when the dsrna polyadenylation step was carried out with undenatured rather than strand-separated dsrna. it is a prerequisite to use dsrna of very high purity because in the presence of even trace amounts of single stranded rna, the dsrna appears to be poorly polyadenylated as judged by its effectiveness as a template for oligo-dt-primed cdna ... | 2000 | 10713375 |
| identification of antigenic regions on vp2 of african horsesickness virus serotype 3 by using phage-displayed epitope libraries. | vp2 is an outer capsid protein of african horsesickness virus (ahsv) and is recognized by serotype-discriminatory neutralizing antibodies. with the objective of locating its antigenic regions, a filamentous phage library was constructed that displayed peptides derived from the fragmentation of a cdna copy of the gene encoding vp2. peptides ranging in size from approximately 30 to 100 amino acids were fused with piii, the attachment protein of the display vector, fuse2. to ensure maximum diversit ... | 2000 | 10725425 |
| cloning and expression of the m5 rna segment encoding outer capsid vp5 of epizootic hemorrhagic disease virus japan serotype 2, ibaraki virus. | the complete nucleotide sequence of a cdna clone representing the m5 rna segment of epizootic hemorrhagic disease virus japan serotype 2 (ehdv-2), ibaraki virus, was determined. the m5 segment is 1641 base pairs long with the single open reading frame which predicts a polypeptide of 527 amino acids. the comparison of the amino acid sequence of the vp5 with those of ehdv-1, bluetongue virus serotype 10, and african horse sickness virus serotype 4 revealed that the protein shared 67%, 57% and 42% ... | 2000 | 10770603 |
| development of probes for typing african horsesickness virus isolates using a complete set of cloned vp2-genes. | a set of cloned full-length vp2-genes from the reference strain of each of the nine serotypes of african horsesickness virus (ahsv) was used to develop probes for typing ahsv isolates. the vp2-gene probes hybridised serotype-specific to purified viral dsrna from its corresponding serotype. no cross-hybridisation was observed between the different ahsv serotypes or with rna from equine encephalosis virus or bluetongue virus (btv) which are related viruses within the genus orbivirus that co-circul ... | 2000 | 10960701 |
| african horse sickness epidemiology: vector competence of south african culicoides species for virus serotypes 3, 5 and 8. | the oral susceptibilities of 17 culicoides species to infection with african horse sickness virus (ahsv) serotypes 3, 5 and 8 were determined by feeding field-collected midges on ahsv infected horse blood. the mean titres of virus in the bloodmeals for the three serotypes of ahsv were between 5.7 and 6.5 log10 tcid50/ml. virus was detected, after 10 days incubation at 23.5 degrees c, in the culicoides imicola kieffer (diptera: ceratopogonidae) that had fed on blood containing ahsv 5 (8.5%) and 8 ... | 2000 | 11016430 |
| regulation of mvm ns1 by protein kinase c: impact of mutagenesis at consensus phosphorylation sites on replicative functions and cytopathic effects. | minute virus of mice ns1, an 83-kda mainly nuclear phosphoprotein, is the only viral nonstructural protein required in all cell types and it is involved in multiple processes necessary for virus propagation. the diversity of functions assigned to ns1, together with the variation of its complex phosphorylation pattern during infection, suggested that the various activities of ns1 could be regulated by distinct phosphorylation events. so far, it has been demonstrated that ns1 replicative functions ... | 2000 | 11112491 |
| the prevalence of different african horsesickness virus serotypes in the onderstepoort area near pretoria, during an outbreak of african horsesickness in south africa in 1995/1996. | during 1995/1996 parts of south africa experienced exceptionally high rainfall. large numbers of culicoides midges were seen and an outbreak of african horsesickness (ahs) followed. in the onderstepoort area, near pretoria in gauteng, a number of horses died of suspected ahs. virus isolation and typing was done from blood and/or organ samples of 21 suspected cases as well as from five zebra which were kept in the area. virus was isolated from 14 of the 21 suspected cases but not from the zebra. ... | 2000 | 10843324 |
| membrane association of african horsesickness virus nonstructural protein ns3 determines its cytotoxicity. | the smallest rna genome segment of african horsesickness virus (ahsv) encodes the nonstructural protein ns3 (24k). ns3 localizes in areas of plasma membrane disruption and is associated with events of viral release. conserved features in all ahsv ns3 proteins include the synthesis of a truncated ns3a protein from the same open reading frame as that of ns3, a proline-rich region, a region of strict sequence conservation and two hydrophobic domains. to investigate whether these features are associ ... | 2001 | 11162806 |
| using climate data to map the potential distribution of culicoides imicola (diptera: ceratopogonidae) in europe. | culicoides imicola, a vector of bluetongue virus and african horse sickness virus, is principally afro-asian in distribution, but has recently been found in parts of europe. a logistic regression model based on climate data (temperature, saturation deficit, rainfall and altitude) and the published distribution of c. imicola in iberia was developed and then applied to other countries in europe, to identify locations where c. imicola could become established. the model identified three temperature ... | 2001 | 11732415 |
| prokaryotical expression of structural and non-structural proteins of hepatitis g virus. | to study the epitope distribution of hepatitis g virus (hgv) and to seek for the potential recombinant antigens for the development of hgv diagnostic reagents. | 2001 | 11819846 |
| variation of african horsesickness virus nonstructural protein ns3 in southern africa. | ns3 protein sequences of recent african horsesickness virus (ahsv) field isolates, reference strains and current vaccine strains in southern africa were determined and compared. the variation of ahsv ns3 was found to be as much as 36.3% across serotypes and 27.6% within serotypes. ns3 proteins of vaccine and field isolates of a specific serotype were found to differ between 2.3% and 9.7%. ns3 of field isolates within a serotype differed up to 11.1%. our data indicate that ahsv ns3 is the second ... | 2001 | 11125168 |
| molecular differentiation of the old world culicoides imicola species complex (diptera, ceratopogonidae), inferred using random amplified polymorphic dna markers. | samples of seven of the 10 morphological species of midges of the culicoides imicola complex were considered. the importance of this species complex is connected to its vectorial capacity for african horse sickness virus (ahsv) and bluetongue virus (btv). consequently, the risk of transmission may vary dramatically, depending upon the particular cryptic species present in a given area. the species complex is confined to the old world and our samples were collected in southern africa, madagascar ... | 2001 | 11472544 |
| bluetongue virus diagnosis of clinical cases by a duplex reverse transcription-pcr: a comparison with conventional methods. | a duplex reverse transcription polymerase chain reaction (rt-pcr) assay for the detection of bluetongue virus (btv) in clinical samples was developed. this assay, which detects the highly conserved s10 region of btv, was assessed for sensitivity and application as a rapid and dependable diagnostic tool by comparison with standard assays of virus detection, such as virus isolation in embryonated chicken eggs and cell culture. simultaneous detection of btv and host beta-actin rnas minimizes the po ... | 2001 | 11543886 |
| definition of neutralizing sites on african horse sickness virus serotype 4 vp2 at the level of peptides. | the antigenic structure of african horse sickness virus (ahsv) serotype 4 capsid protein vp2 has been determined at the peptide level by pepscan analysis in combination with a large collection of polyclonal antisera and monoclonal antibodies. vp2, the determinant for the virus serotype and an important target in virus neutralization, was found to contain 15 antigenic sites. a major antigenic region containing 12 of the 15 sites was identified in the region between residues 223 and 400. a second ... | 2001 | 11562535 |
| eliciting antigen-specific egg-yolk igy with naked dna. | immunization with naked dna was used to elicit chicken egg yolk antibodies (igy). layer hens were inoculated with plasmid dna encoding the enhanced green fluorescent protein, the fusion protein of newcastle disease virus, and vp2 of african horse sickness virus. igy was extracted from egg yolks by polyethylene glycol precipitation. specific antibodies were present in the yolks of eggs from hens immunized with each of the three different plasmids. this approach to raising polyclonal antibodies ob ... | 2001 | 11570510 |
| effect of temperature on the transmission of orbiviruses by the biting midge, culicoides sonorensis. | the influence of temperature on the likelihood of culicoides sonorensis wirth & jones (diptera: ceratopogonidae) transmitting african horse sickness virus (ahsv) serotypes 4 and 6, bluetongue virus (btv) serotypes 10 and 16 and epizootic haemorrhagic disease of deer virus (ehdv) serotype 1 was investigated. extrinsic incubation periods (eip), vector competence and vector survival were determined at 15, 20, 25 and 30 degrees c. the effect of humidity on vector survival was also investigated by ma ... | 2002 | 12109708 |
| high mutation rate in the ns1 gene of parvovirus b19 dna amplified from skeletal muscle of a case of mixed connective tissue disease. | 2002 | 12096244 | |
| the protective efficacy of a recombinant vp2-based african horsesickness subunit vaccine candidate is determined by adjuvant. | we previously demonstrated that soluble baculovirus-expressed african horsesickness virus (ahsv) serotype 5 vp2 protein (ahsv5 rvp2) elicits neutralising antibodies in guinea pigs. we have now determined the immunogenicity of soluble ahsv5 rvp2 in horses when administered in three different adjuvant types, isa-50, aluminium phosphate and different saponin preparations. doses of 10 and 50microg of rvp2 administered with saponin induced full protection to a lethal challenge, albeit with dose-relat ... | 2002 | 11803068 |
| a comparison of the vector competence of the biting midges, culicoides (avaritia) bolitinos and c. (a.) imicola, for the bryanston serotype of equine encephalosis virus. | equine encephalosis virus (eev) is widespread and prevalent in southern africa. in this study, the oral susceptibility of culicoides (avaritia) imicola kieffer (diptera: ceratopogonidae) to eev was confirmed. in addition, c. (a.) bolitinos meiswinkel, collected in the high-lying eastern free state, south africa, was systemically infected with the bryanston serotype of eev after feeding through a membrane on artificially infected equine blood containing 4.7 log10 pfu/ml of eev. the mean infectivi ... | 2002 | 12510889 |
| cloning of complete genome sets of six dsrna viruses using an improved cloning method for large dsrna genes. | cloning full-length large (>3 kb) dsrna genome segments from small amounts of dsrna has thus far remained problematic. here, a single-primer amplification sequence-independent dsrna cloning procedure was perfected for large genes and tailored for routine use to clone complete genome sets or individual genes. nine complete viral genome sets were amplified by pcr, namely those of two human rotaviruses, two african horsesickness viruses (ahsv), two equine encephalosis viruses (eev), one bluetongue ... | 2002 | 12185276 |
| a group-specific, indirect sandwich elisa for the detection of equine encephalosis virus antigen. | a polyclonal antibody-based, group-specific, indirect, sandwich elisa (s-elisa) for the detection of equine encephalosis virus (eev) antigen was developed. purified eev particles were titrated in the s-elisa and the limit of detection was determined to be approximately 9.0 ng of antigen/ml (0.45 ng/well). positive s-elisa reactions were recorded with seven serologically distinct eev serotypes. no cross-reactions were recorded with other arboviruses including african horse sickness virus (ahsv) s ... | 2003 | 12951221 |
| oral susceptibility of south african culicoides species to live-attenuated serotype-specific vaccine strains of african horse sickness virus (ahsv). | the oral susceptibility of livestock-associated south african culicoides midges (diptera: ceratopogonidae) to infection with the tissue culture-attenuated vaccine strains of african horse sickness virus (ahsv) currently in use is reported. field-collected culicoides were fed on horse blood-virus mixtures each containing one of the seven serotype-specific vaccine strains of ahsv, namely serotypes 1, 2, 3, 4, 6, 7 and 8. the mean titres of virus in the bloodmeals for the seven vaccine strains were ... | 2003 | 14651659 |
| variation in the ns3 gene and protein in south african isolates of bluetongue and equine encephalosis viruses. | bluetongue virus (btv) and equine encephalosis virus (eev) are agriculturally important orbiviruses transmitted by biting midges of the genus culicoides. the smallest viral genome segment, s10, encodes two small nonstructural proteins, ns3 and ns3a, which mediate the release of virus particles from infected cells and may subsequently influence the natural dispersion of these viruses. the ns3 gene and protein sequences of south african isolates of these viruses were determined, analysed and compa ... | 2003 | 12604809 |
| a first full outer capsid protein sequence data-set in the orbivirus genus (family reoviridae): cloning, sequencing, expression and analysis of a complete set of full-length outer capsid vp2 genes of the nine african horsesickness virus serotypes. | the outer capsid protein vp2 of african horsesickness virus (ahsv) is a major protective antigen. we have cloned full-length vp2 genes from the reference strains of each of the nine ahsv serotypes. baculovirus recombinants expressing the cloned vp2 genes of serotypes 1, 2, 4, 6, 7 and 8 were constructed, confirming that they all have full open reading frames. this work completes the cloning and expression of the first full set of ahsv vp2 genes. the clones of vp2 genes of serotypes 1, 2, 5, 7 an ... | 2003 | 12692299 |
| vp2 gene phylogenetic characterization of field isolates of african horsesickness virus serotype 7 circulating in south africa during the time of the 1999 african horsesickness outbreak in the western cape. | we present the first vp2-gene phylogenetic analysis of african horsesickness (ahs) viruses within a serotype. thirteen ahsv 7 isolates were obtained from cases that occurred in south africa during 1998-1999, and three were historical ahsv 7 isolates. the goals were to start a database of isolates of known location and time of isolation and to determine if we could identify the origin of an ahs outbreak in the surveillance area in the western cape. we prepared full-length cdna copies of the vp2-g ... | 2003 | 12782364 |
| development of competitive elisa for serodiagnosis on african horsesickness virus using baculovirus expressed vp7 and monoclonal antibody. | vp7, the sero-group common antigen, of african horsesickness virus (ahsv-4) was expressed in insect cells by recombinant baculovirus. to develop a specific diagnostic method, monoclonal antibody (mab) against vp7 was prepared and investigated as diagnostic reagent with the baculovirus expressed vp7. however, the mab against vp7 of ahsv cross-reacted with chuzan virus by the indirect immunofluorescence assay (ifa), confirming the presence of conserved domain of vp7 among orbiviruses. this study d ... | 2003 | 14500122 |
| spatial distribution of culicoides species in portugal in relation to the transmission of african horse sickness and bluetongue viruses. | surveillance of culicoides (diptera: ceratopogonidae) biting midge vectors was carried out at 87 sites within a 50 x 50 km grid distributed across portugal, using light trap collections at the time of peak midge abundance. culicoides imicola (kieffer) made up 66% of the 55 937 culicoides in these summer collections. it was highly abundant in the central eastern portion of portugal, between 37 degrees 5' n and 41 degrees 5' n, and in a band across to the lisbon peninsula (at around 38 degrees 5' ... | 2003 | 12823834 |
| evidence for a new field culicoides vector of african horse sickness in south africa. | between february and may 1998, approximately 100 horses died of african horse sickness (ahs) in the cooler, mountainous, central region of south africa. on 14 affected farms, 156,875 culicoides of 27 species were captured. c. imicola kieffer, hitherto considered the only field vector for ahs virus (ahsv), constituted <1% of the total culicoides captured, and was not found on 29% of the farms. in contrast, 65% of the culicoides were c. bolitinos meiswinkel, and was found on all farms. five isolat ... | 2003 | 12900162 |
| phylogenetic status and matrilineal structure of the biting midge, culicoides imicola, in portugal, rhodes and israel. | the biting midge culicoides imicola kieffer (diptera: ceratopogonidae) is the most important old world vector of african horse sickness (ahs) and bluetongue (bt). recent increases of bt incidence in the mediterranean basin are attributed to its increased abundance and distribution. the phylogenetic status and genetic structure of c. imicola in this region are unknown, despite the importance of these aspects for bt epidemiology in the north american bt vector. in this study, analyses of partial m ... | 2003 | 14651651 |
| geographical and seasonal distribution of the bluetongue virus vector, culicoides imicola, in central italy. | following the first incursion of bluetongue virus (btv) into italy, the geographical and seasonal distribution of the biting midge culicoides imicola kieffer (diptera: ceratopogonidae), the main vector of btv and african horse sickness virus, was investigated in two regions of central italy (lazio and tuscany). surveillance of culicoides was carried out between july 2001 and december 2002 using light traps: 1917 collections were made in 381 trap sites, well distributed across both regions. durin ... | 2003 | 14651652 |
| culicoides midges in catalonia (spain), with special reference to likely bluetongue virus vectors. | midges of the genus culicoides (diptera: ceratopogonidae) were trapped weekly from may 2001 through december 2002 on two farms in the province of barcelona (spain). dosrius farm was stocked with sheep and goats whereas bellaterra farm had only sheep. this trapping programme was carried out within the framework of an investigation into the occurrence/absence of possible vectors of bluetongue virus (btv) in mainland spain. a total of 30,079 culicoides specimens were collected from 165 light trap c ... | 2003 | 12941013 |
| nature and duration of protective immunity to bluetongue virus infection. | genetic engineering offers a variety of approaches to producing viral vaccines. an exciting advance in this field is the ability to construct virus-like particles (vlps) that resemble their natural counterparts but lack genetic information. to develop a rationally designed vaccine for bluetongue disease of sheep that is caused by virus (btv), we have synthesised individual btv proteins and btv-like particles (vlps and clps) using baculovirus expression systems and insect cell cultures. a series ... | 2003 | 14677687 |
| a comparison of different orbivirus proteins that could affect virulence and pathogenesis. | the factors that determine the virulence and pathogenesis characteristics of bluetongue virus (btv), african horse sickness virus (ahsv) and other orbiviruses are not well known. with respect to the viral proteins that are expected to play a role it may be assumed that proteins, such as the outer capsid proteins vp2 and vp5, that are involved in the attachment of virus particles to target cells and influence replication efficiency are particularly important. equally important are viral proteins ... | 2004 | 20422564 |
| control and eradication of african horse sickness with vaccine. | african horse sickness (ahs) is an infectious but no-contagious viral disease of equidae with high mortality in horses. the disease is caused by an arthropod-borne double-stranded rna virus within the genus orbivirus of the family reoviridae transmitted by at least two species of culicoides. nine different serotypes have been described. the nine serotypes of ahs have been described in eastern and southern africa. only ahs serotypes 9 and 4 have been found in west africa from where they occasiona ... | 2004 | 15742636 |
| african horsesickness virus serotyping and identification of multiple co-infecting serotypes with a single genome segment 2 rt-pcr amplification and reverse line blot hybridization. | since protection against african horsesickness (ahs) is serotype-specific, rapid serotyping of ahsv is crucial to identify the correct vaccine serotype for efficient control of the spread of ahs outbreaks, especially when they occur in non-endemic regions. this paper describes the first one-day serotyping procedure that requires only a single rt-pcr and hybridization and which can identify multiple serotypes in mixed infections in one assay. the same region of genome segment 2 of all nine ahsv s ... | 2004 | 15488620 |
| african horse sickness. | african horse sickness virus (ahsv) causes a non-contagious, infectious insect-borne disease of equids and is endemic in many areas of sub-saharan africa and possibly yemen in the arabian peninsula. however, periodically the virus makes excursions beyond its endemic areas and has at times extended as far as india and pakistan in the east and spain and portugal in the west. the vectors are certain species of culicoides biting midge the most important of which is the afro-asiatic species c. imicol ... | 2004 | 15236676 |
| characterization of the nucleic acid binding activity of inner core protein vp6 of african horse sickness virus. | minor structural protein vp6 is the putative helicase of african horse sickness virus (ahsv), of the genus orbivirus in the reoviridae family. we investigated how the protein interacts with double-stranded (ds) rna and other nucleic acids. binding was assayed using an electrophoretic migration retardation assay and a nucleic acid overlay protein blot assay. vp6 bound double and single stranded rna and dna in a nacl concentration sensitive reaction. of six truncated vp6 peptides investigated, two ... | 2005 | 15986179 |
| preparation of recombinant african horse sickness virus vp7 antigen via a simple method and validation of a vp7-based indirect elisa for the detection of group-specific igg antibodies in horse sera. | this paper describes the production and purification of a group-specific recombinant protein vp7 of african horse sickness virus serotype 3 (ahsv-3) and validation of an i-elisa for the detection of igg-antibodies to vp7 in horse sera. baculovirus-expressed vp7 crystals were purified from infected insect cells. analytical accuracy of the i-elisa was examined using sera (n = 38) from an experimentally infected horse, from foals born to vaccinated mares, from guinea-pigs immunized with nine seroty ... | 2005 | 15737417 |
| differentiation of culicoides obsoletus and culicoides scoticus (diptera: ceratopogonidae) based on mitochondrial cytochrome oxidase subunit i. | culicoides obsoletus (meigen) and culicoides scoticus downes & kettle (diptera: ceratopogonidae) are sibling species of the obsoletus group. this group comprises species of biting midges that are suspect vectors of bluetongue virus (family reoviridae, genus orbivirus, btv) and african horse sickness virus (family reoviridae, genus orbivirus, ahsv). btv and ahsv have been isolated several times from females of this group, although it has not been possible to determine the particular species harbo ... | 2005 | 16465744 |
| african horse sickness--a serious disease. | 2006 | 16739521 | |
| nonstructural protein 3 of bluetongue virus assists virus release by recruiting escrt-i protein tsg101. | the release of bluetongue virus (btv) and other members of the orbivirus genus from infected host cells occurs predominantly by cell lysis, and in some cases, by budding from the plasma membrane. two nonstructural proteins, ns3 and ns3a, have been implicated in this process. here we show that both proteins bind to human tsg101 and its ortholog from drosophila melanogaster with similar strengths in vitro. this interaction is mediated by a conserved psap motif in ns3 and appears to play a role in ... | 2006 | 16352570 |
| a simple and rapid method for detection of african horse sickness virus serogroup in cell cultures using rt-pcr. | 2006 | 16437307 | |
| investigations on outbreaks of african horse sickness in the surveillance zone in south africa. | confirmed outbreaks of african horse sickness (ahs) occurred in the surveillance zone of the western cape in 1999 and 2004, both of which led to a two-year suspension on the export of horses. light trap surveys in the outbreak areas showed that known vector competent culicoides species, notably c. imicola, were abundant and present in numbers equal to those in the traditional ahs endemic areas. isolations of ahs virus serotypes 1 and 7, equine encephalosis virus, and bluetongue virus from field- ... | 2006 | 17361773 |
| an epidemiological investigation of the african horsesickness outbreak in the western cape province of south africa in 2004 and its relevance to the current equine export protocol. | african horsesickness (ahs) is a controlled disease in south africa. the country is divided into an infected area and a control area. an outbreak of ahs in the control area can result in a ban of exports for at least 2 years. a retrospective epidemiological study was carried out on data collected during the 2004 ahs outbreak in the surveillance zone of the ahs control area in the western cape province. the objective of this study was to describe the 2004 outbreak and compare it with the 1999 ahs ... | 2006 | 17458343 |
| real-time polymerase chain reaction to detect bluetongue virus in blood samples. | the authors describe a real-time reverse transcriptase polymerase chain reaction (rt-pcr) to detect bluetongue viruses (btv) in blood samples. the primers and taqman probes used were specific for a conserved region of btv rna segment 5, which encodes non-structural protein ns1. the method was able to detect strains of btv serotypes 2, 4, 9 and 16 isolated in italy, and their respective vaccine strains. the limit of detection was 5.0x10-(3) tcid(50) per ml of sample. the assay did not amplify rna ... | 2007 | 20411502 |
| a duplex rt-pcr assay for detection of genome segment 7 (vp7 gene) from 24 btv serotypes. | since 1998, six distinct serotypes of bluetongue virus (btv) have invaded southern and central europe, persisting in some regions for up to 6 years and resulting in the deaths of >1.8 million sheep. rapid and reliable methods of virus detection and identification play an essential part in our fight against bluetongue disease (bt). we have therefore developed and evaluated a duplex, one-step rt-pcr assay that detects genome segment 7 (encoding the major serogroup (virus-species) specific antigen ... | 2007 | 17241676 |
| silencing of african horse sickness virus vp7 protein expression in cultured cells by rna interference. | rna interference (rnai) is the process by which double-stranded rna directs sequence-specific degradation of homologous mrna. short interfering rnas (sirnas) are the mediators of rnai and represent powerful tools to silence gene expression in mammalian cells including genes of viral origin. in this study, we applied sirnas targeting the vp7 gene of african horse sickness virus (ahsv) that encodes a structural protein required for stable capsid assembly. using a vp7 expression reporter plasmid an ... | 2007 | 17851744 |
| comparative descriptions of the pupae of five species of the culicoides imicola complex (diptera, ceratopogonidae) from south africa. | the viruses causing the economically important livestock diseases of african horse sickness (ahs) and bluetongue (bt) are transmitted by biting midges of the genus culicoides (diptera, ceratopogonidae). in the old world the most important vectors of these diseases are culicoides imicola kieffer, 1913, culicoides brevitarsis kieffer, 1917 and culicoides bolitinos meiswinkel, 1989. all three of these vectors belong to the imicola complex of the subgenus avaritia fox, 1955. this species complex now ... | 2007 | 17883197 |
| virus recovery rates for wild-type and live-attenuated vaccine strains of african horse sickness virus serotype 7 in orally infected south african culicoides species. | previously reported virus recovery rates from culicoides (avaritia) imicola kieffer and culicoides (avaritia) bolitinos meiswinkel (diptera, ceratopogonidae) orally infected with vaccine strain of african horse sickness virus serotype 7 (ahsv-7) were compared with results obtained from concurrently conducted oral infections with five recent ahsv-7 isolates from naturally infected horses from various localities in south africa. culicoides were fed sheep bloods spiked with 10(7.6) tcid(50)/ml of a ... | 2007 | 18092976 |
| molecular epidemiology of the african horse sickness virus s10 gene. | between 2004 and 2006, 145 african horse sickness viruses (ahsv) were isolated from blood and organ samples submitted from south africa to the faculty of veterinary science, university of pretoria. all nine serotypes were represented, with a range of 3-60 isolates per serotype. the rna small segment 10 (s10) nucleotide sequences of these isolates were determined and the phylogeny investigated. ahsv, bluetongue virus (btv) and equine encephalosis virus (eev) all formed monophyletic groups and btv ... | 2008 | 18420793 |
| real-time fluorogenic reverse transcription polymerase chain reaction assay for detection of african horse sickness virus. | african horse sickness is an arthropod-borne disease of the equine included in the world organization for animal health (oie) list with important economic consequences for horse trade. the disease is caused by african horse sickness virus (ahsv; family reoviridae, genus orbivirus), which is transmitted by culicoides midges. it is endemic in sub-saharan africa, spreading occasionally outside this area where the occurrence of culicoides vectors allows virus transmission. currently, only convention ... | 2008 | 18460619 |
| novel gel-based and real-time pcr assays for the improved detection of african horse sickness virus. | in order to improve, ensure and accelerate the diagnosis of african horse sickness, a highly devastating, transboundary animal disease listed by the world animal health organisation, (oie) three novel diagnostic pcr assays were developed and tested in this study. the reverse transcription-pcr (rt-pcr) tests were the following: (a) a conventional, gel-based rt-pcr, (b) a real-time pcr with sybr-green-named rrt-pcr sybr-green-, and (c) a real-time pcr rrt-pcr with taqman probe (termed rrt-pcr taqm ... | 2008 | 18501973 |
| a serological survey of african horse sickness in botswana. | a retrospective serological survey of african horse sickness (ahs) in botswana covering a 10-year period (1995-2004) is reported. the survey involved horses showing clinical symptoms of the disease; the horses had not been vaccinated against ahs. over the period surveyed, serological evidence suggestive of infection with ahs virus (ahsv) was found in 99 clinical cases out of which 41.4% (41/99) cases were found during the 1st half (1995-1999) and 58.6 % (58/99) cases were found in the 2nd half o ... | 2008 | 18678192 |
| bioinformatic analysis suggests that the orbivirus vp6 cistron encodes an overlapping gene. | the genus orbivirus includes several species that infect livestock - including bluetongue virus (btv) and african horse sickness virus (ahsv). these viruses have linear dsrna genomes divided into ten segments, all of which have previously been assumed to be monocistronic. | 2008 | 18489030 |
| evaluation of the pathogenicity of african horsesickness (ahs) isolates in vaccinated animals. | the polyvalent african horsesickness (ahs) attenuated live vaccine (alv) produced by onderstepoort biological products (obp) ltd., south africa, has been associated with some safety concerns and alleged cases of vaccine failure or vaccine-induced disease. the risk of reassortment and reversion to virulence is a common concern associated with the use of alvs, and a phenomenon reported for viruses with segmented rna genomes. the purpose of this study was to determine whether or not reassortment of ... | 2008 | 18682269 |
| serotype-specific detection of african horsesickness virus by real-time pcr and the influence of genetic variations. | real-time pcr hybridization probe sets were tested for the specific detection of amplified genome segment 2 cdna from all nine serotypes of african horsesickness virus (ahsv). the hybridization probes were derived from the sequences of genome segments 2 of the nine reference strains of the virus and were designed to have clearly distinguishable peak melting temperatures. viral dsrna from each of the serotypes was specifically detected after reverse transcription, real-time pcr and melting curve ... | 2008 | 18793672 |
| improved strategies for sequence-independent amplification and sequencing of viral double-stranded rna genomes. | this paper reports significant improvements in the efficacy of sequence-independent amplification and quality of sequencing of viruses with segmented double-stranded rna (dsrna) genomes. we demonstrate that most remaining bottlenecks in dsrna virus genome characterization have now been eliminated. both the amplification and sequencing technologies used require no previous sequence knowledge of the viral dsrna, there is no longer a need to separate genome segments or amplicons and the sequence-de ... | 2009 | 19264638 |
| pcr detection of african horse sickness virus serogroup based on genome segment three sequence analysis. | a nested reverse transcriptase (rt) polymerase chain reaction (rt-pcr), for rapid detection of african horse sickness virus (ahsv) double-stranded ribonucleic acid (dsrna) in cell culture and tissue samples, was developed and evaluated. using an outer pair of primers (p1 and p2), selected from genome segment three of ahsv serotype 6 (ahsv-6), the rt-pcr-based assay resulted in amplification of a 890 base pair (bp) primary pcr product. rnas from the nine vaccine strains of ahsv, and a number of a ... | 2009 | 19442836 |
| protective immunization of horses with a recombinant canarypox virus vectored vaccine co-expressing genes encoding the outer capsid proteins of african horse sickness virus. | we describe the development and preliminary characterization of a recombinant canarypox virus vectored (alvac) vaccine for protective immunization of equids against african horse sickness virus (ahsv) infection. horses (n=8) immunized with either of two concentrations of recombinant canarypox virus vector (alvac-ahsv) co-expressing synthetic genes encoding the outer capsid proteins (vp2 and vp5) of ahsv serotype 4 (ahsv-4) developed variable titres (<10-80) of virus-specific neutralizing antibod ... | 2009 | 19490959 |
| biting rates of culicoides midges (diptera: ceratopogonidae) on sheep in northeastern spain in relation to midge capture using uv light and carbon dioxide-baited traps. | biting midges in the genus culicoides (diptera: ceratopogonidae) were collected near sunset by direct aspiration from sheep in northeastern spain to determine species-specific biting rates and crepuscular activity. midges were also collected by uv-baited light traps and co2-baited traps over the same period to compare species diversity and abundance using these common surveillance methods to actual sheep attack rates. culicoides aspirated from sheep included c. obsoletus, c. parroti, c. scoticus ... | 2009 | 19496435 |
| induction of antibody responses to african horse sickness virus (ahsv) in ponies after vaccination with recombinant modified vaccinia ankara (mva). | african horse sickness virus (ahsv) causes a non-contagious, infectious disease in equids, with mortality rates that can exceed 90% in susceptible horse populations. ahsv vaccines play a crucial role in the control of the disease; however, there are concerns over the use of polyvalent live attenuated vaccines particularly in areas where ahsv is not endemic. therefore, it is important to consider alternative approaches for ahsv vaccine development. we have carried out a pilot study to investigate ... | 2009 | 19543394 |
| rapid and sensitive detection of african horse sickness virus by real-time pcr. | a highly sensitive and specific taqman-mgb real-time rt-pcr assay has been developed and standardised for the detection of african horse sickness virus (ahsv). primers and mgb probe specific for ahsv were selected within a highly conserved region of genome segment 7. the robustness and general application of the diagnostic method were verified by the detection of 12 ahsv isolates from all of the nine serotypes. the analytical sensitivity ranged from 0.001 to 0.15 tcid(50) per reaction, depending ... | 2009 | 18782637 |
| the oral susceptibility of south african field populations of culicoides to african horse sickness virus. | twenty-two isolates of african horse sickness virus (ahsv), representing its distinct serotypes, geographical and historical origins, were fed to three populations of south african livestock-associated culicoides spp. (diptera, ceratopogonidae). infective blood meals included 12 recent isolates, nine historical reference strains and one live attenuated vaccine strain serotype 7 (ahsv-7) of the virus. field-collected midges were fed through a chicken-skin membrane on sheep blood spiked with one o ... | 2009 | 19941602 |
| genome segment reassortment identifies non-structural protein ns3 as a key protein in african horsesickness virus release and alteration of membrane permeability. | the role of african horsesickness virus (ahsv) nonstructural membrane protein ns3 in determining the effects of ahsv infection on vero cells was examined. ns3 protein sequences are highly variable and cluster into three phylogenetic groups, alpha, beta, and gamma. three ahsv strains, with ns3 from alpha, beta, or gamma, were shown to have quantitatively different phenotypes in vero cells. reassortants between these strains, in which the s10 genome segment encoding ns3 was exchanged alone or with ... | 2009 | 19153641 |
| adaptive strategies of african horse sickness virus to facilitate vector transmission. | african horse sickness virus (ahsv) is an orbivirus that is usually transmitted between its equid hosts by adult culicoides midges. in this article, we review the ways in which ahsv may have adapted to this mode of transmission. the ahsv particle can be modified by the ph or proteolytic enzymes of its immediate environment, altering its ability to infect different cell types. the degree of pathogenesis in the host and vector may also represent adaptations maximising the likelihood of successful ... | 2009 | 19094921 |
| standardization and validation of an immunoperoxidase assay for the detection of african horse sickness virus in formalin-fixed, paraffin-embedded tissues. | an immunoperoxidase assay for the detection of african horse sickness virus (ahsv) in formalin-fixed tissues is a valuable tool in the study of the pathogenesis of the disease, as well as a useful addition to existing diagnostic tests when only preserved tissues are available. an assay that uses hamblin antiserum in a basic avidin-biotin complex detection system was standardized and validated in accordance with the guidelines of the american association of veterinary laboratory diagnosticians su ... | 2009 | 19737761 |
| in vivo cross-protection to african horse sickness serotypes 5 and 9 after vaccination with serotypes 8 and 6. | the polyvalent african horsesickness (ahs) attenuated live virus (ahs-alv) vaccine produced at onderstepoort biological products incorporates 7 of the 9 known serotypes circulating in southern africa. serological cross-reaction has been shown in vitro to serotypes 5 and 9 by serotypes 8 and 6 respectively, but the degree of in vivo cross-protection between these serotypes in vaccinated horses has not previously been reported. due to the increasing incidence of ahs serotypes 5 and 9 in the field, ... | 2010 | 20638456 |
| assessment of bluetongue viraemia in sheep by real-time pcr and correlation with viral infectivity. | inoculation of embryonated chicken eggs is the standard method for the titration of infectious bluetongue virus (btv). here, six rna extraction methods coupled with optimised dsrna denaturation and real-time rt-pcr were evaluated for the quantitation of btv in blood samples from experimentally infected sheep and results were correlated to infectious virus titres. an exogenous dsrna internal control (ic) from the closely related epizootic hemorrhagic disease virus (ehdv) was used to assess the ef ... | 2010 | 20691732 |
| tissue and cell tropism of african horse sickness virus demonstrated by immunoperoxidase labeling in natural and experimental infection in horses in south africa. | tissues from 196 experimental and confirmed natural cases of african horse sickness (all 9 serotypes) were examined with a standardized and validated immunohistochemical assay for detection of the causative virus. the study confirmed that heart and lung are the main target tissues for african horse sickness virus (across all serotypes), followed closely by spleen. it also indicated that microvascular endothelial cells and monocyte-macrophages are the main target cells for virus replication. the ... | 2010 | 20484177 |
| a reverse genetics system of african horse sickness virus reveals existence of primary replication. | african horse sickness virus (ahsv), a member of the orbivirus genus of the family reoviridae, is an insect-vectored pathogen of horses of concern to the equine industry. studies on ahsv replication and pathogenesis have been hampered by the lack of reverse genetics allowing targeted mutation of viral genomes. we demonstrate that ahsv single-stranded rna synthesized in vitro (core transcripts) is infectious and that there are distinct primary and secondary stages of the replication cycle. transf ... | 2010 | 20600010 |