Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| isolation and identification of african horse sickness virus during an outbreak in lagos, nigeria. | an outbreak of african horse sickness involving two horse stables in lagos, nigeria, was investigated. inoculation of blood from infected horses into suckling albino mice resulted in isolation of a virus which was identified as african horse sickness virus by the complement fixation test. the clinical, pathological and epizootiological findings (reported elsewhere) were consistent with african horse sickness. potential threats of the epidemic to international horse trade are briefly highlighted. | 1993 | 8219337 |
| diagnosis and molecular epidemiology of the african horse sickness virus by the polymerase chain reaction and restriction patterns. | african horse sickness is a viral disease caused by an orbivirus belonging to the reoviridae family. this paper describes a polymerase chain reaction (pcr) for amplifying segments 7, which encode for vp 7, a protein common to the 9 known serotypes of this virus. a reverse transcription step is necessary before amplification. no amplified product could be observed in cell cultures infected with other equine viruses. the amplified dnas were digested to completion by 8 different restriction enzymes ... | 1993 | 8260960 |
| circulation of african horsesickness virus in zebra (equus burchelli) in the kruger national park, south africa, as measured by the prevalence of type specific antibodies. | in the kruger national park 75% of zebra foals are born in october-march and they lose their passive immunity against african horsesickness virus (ahsv) when they are 5-6 months old. one month later infection with different serotypes of ahsv amounts to 31% and thereafter infections increase rapidly to almost 100% before the foals are 12 months old. the capability of zebra to maintain ahsv is clearly illustrated by the continuing infections during every month of the year with a peak period in win ... | 1993 | 8332321 |
| characterization of virulence variants of african horsesickness virus. | there are three clinicopathologic syndromes associated with african horsesickness (ahs) virus infection in horses. these different forms of ahs (pulmonary, cardiac, and fever forms) vary in the organs affected, the severity of lesions, time of onset of clinical signs and mortality rates. we have studied the effects of infection with three cell culture passaged variants of ahs virus in naive north american horses. one of these viruses, ahs/4sp, consistently caused the pulmonary form of ahs with r ... | 1993 | 8337849 |
| current status of the diagnosis and control of african horse sickness. | african horse sickness (ahs) is an infectious, non-contagious, highly fatal viral disease of equidae, transmitted by arthropod vectors of the genus culicoides, and endemic in africa south and east of the sahara. the disease is caused by a virus of the reoviridae family, genus orbivirus, and 9 serotypes have been recognized. recent outbreaks of ahs in the iberian peninsula and northern africa emphasize the need for accurate diagnosis and rapid implementation of control measures. in this paper, th ... | 1993 | 8343805 |
| the complete nucleotide sequence of african horsesickness virus serotype 4 (vaccine strain) segment 4, which encodes the minor core protein vp4. | the complete sequence of rna segment 4 of african horsesickness virus serotype 4 (ahsv-4) vaccine strain was determined from the full-length cdna clone inserted into pbr322. the rna is 1978 bp long (m(r) 1.27 x 10(6)) and contains an open reading frame encoding a protein of 642 amino acids (m(r) 75826) with a net charge of +10 at neutral ph. the 5' and 3' termini of ahsv-4 segment 4,5'gtttat... and ...ccttac3', were different from orbivirus characteristic terminal sequences, being 5'gttaaa... an ... | 1993 | 8346671 |
| african horse sickness. | ahs is a noncontagious vector-borne disease of equidae caused by orbiviruses. species susceptibility in decreasing order is horses, mules, donkeys, and zebras. the main vectors of ahs are culicoides. the disease is endemic in sub-saharan africa, but epizootics have occurred outside of this area on several occasions. the most recent outbreaks outside of the endemic area were in spain, morocco, and portugal between 1987 and 1990. ahs causes mortality up to 95% and is classically divided into four ... | 1993 | 8358648 |
| purification of viruses by electrophoresis in sucrose concentration gradients. 1972. | zone electrophoresis (ze) in concentration gradients of sucrose proved to be a powerful technique in the purification of viruses although it is seldomly used as a single step for the separation of the infective agent from extraneous matter but usually as a final procedure. no difficulties were experienced in the purification of plant viruses with ze possibly because of the resistance of the agents to the chloroform butanol treatment which the impure plant viruses received prior to the ze. likewi ... | 1993 | 8367394 |
| seroepidemiological study of african horse sickness virus in the gambia. | an indirect enzyme-linked immunosorbent assay was used for the screening of horse sera from the gambia for antibodies against african horse sickness virus (ahsv). the ahsv antigen used for coating was semipurified according to the method of manning and chen (curr. microbiol. 4:381, 1980); control mock-infected vero cell antigen was treated in the same manner. a total of 459 horse serum samples were assayed at a single dilution (1:10), and their reactivities were compared with those of reference ... | 1993 | 8370760 |
| group-reactive elisas for detecting antibodies to african horsesickness and equine encephalosis viruses in horse, donkey, and zebra sera. | group-reactive enzyme-linked immunosorbent assays (elisas) were developed to selectively detect antibodies to african horsesickness virus (ahsv) and equine encephalosis virus (eev), 2 orbiviruses that infect equids. in indirect elisa, guinea pig antisera to all known ahsv or eev serotypes recognized immobilized ahsv serotype 3 or eev cascara, respectively. antisera from naturally infected animals did not cross-react with their respective heterologous viruses. the elisa was used in parallel with ... | 1993 | 8385502 |
| use of a digoxigenin-labeled rna probe to detect all 24 serotypes of bluetongue virus in cell culture. | a digoxigenin-labeled rna probe, corresponding to the section of the bluetongue virus (btv) serotype 17 genome coding for nonstructural protein-1 (ns1), was applied to noninfected cell cultures and cell cultures infected with 24 different serotypes of btv, 2 serotypes of epizootic hemorrhagic disease virus, and african horse sickness virus type 4. the probe hybridized to all cell cultures infected with the various btv serotypes but did not hybridize to noninfected cell cultures or cell cultures ... | 1993 | 8389596 |
| a rapid method for the purification of the mef1 strain of poliomyelitis virus. 1954. | 1993 | 8396245 | |
| separation of small infective components of mef1 poliomyelitis and horsesickness viruses by migration into agar gels. 1955. | 1993 | 8396246 | |
| characterization of african horsesickness virus serotype 4-induced polypeptides in vero cells and their reactivity in western immunoblotting. | the structural and non-structural proteins induced by african horsesickness virus serotype 4 (ahsv-4) in infected vero cells were analysed by sds-page. twenty-two virus-induced polypeptides were detected in infected cells by comparison with the polypeptides of mock-infected cells, of which four major (vp2, vp3, vp5 and vp7) and three minor (vp1, vp4 and vp6) structural proteins and four non-structural proteins (p58, p48, p21 and p20) were shown to be virus-coded, as deduced from electrophoretic ... | 1993 | 8423451 |
| african horse sickness viruses isolated in kenya. | 1993 | 8498004 | |
| rapid generation of monoclonal antibody-secreting hybridomas against african horse sickness virus by in vitro immunization and the fusion/cloning technique. | splenocytes from non-immune mice were stimulated in vitro using an equimolar mixture of factors from mixed lymphocyte reaction (mlr) and from phorbol-12-myristate 13-acetate (pma) stimulated el-4 cells, and concomitantly immunized with inactivated african horse sickness virus (ahsv) antigen serotype 4 or viral proteins 2 and 5 from ahsv serotype 9. fusion with nso myeloma cells was performed five days after primary or secondary stimulation/immunization. the record of hybridoma growth after a sta ... | 1993 | 8505546 |
| 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 ... | 1993 | 8102076 |
| 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 ... | 1993 | 8111431 |
| 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 ... | 1993 | 8113344 |
| 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 ... | 1993 | 8134660 |
| further studies on the efficacy of an inactivated african horse sickness serotype 4 vaccine. | the immunity induced by two inoculations of a commercial inactivated african horse sickness (ahs) serotype 4 (ahsv-4) vaccine was studied. no adverse reaction was observed in five horses following vaccination. following challenge-inoculation, no clinical signs attributable to ahs, no viraemia indicating infection, and no anamnestic response was observed in the vaccinated ponies. two control ponies developed clinical signs typical of ahs, high levels of viraemia, and died 7 and 8 days postchallen ... | 1994 | 8147096 |
| identification of domains in bluetongue virus vp3 molecules essential for the assembly of virus cores. | bluetongue virus (btv) cores consist of the viral genome and five proteins, including two major components (vp3 and vp7) and three minor components (vp1, vp4, and vp6). vp3 proteins form an inner scaffold for the deposition on the core of the surface layer of vp7. vp3 also encapsidates and interacts with the three minor proteins. the btv vp3 protein consists of 901 amino acids and has a sequence that is a highly conserved among btv serotypes and other orbiviruses (e.g., epizootic hemorrhagic dis ... | 1994 | 8151751 |
| diagnosis of the african horse sickness virus serotype 4 by a one-tube, one manipulation rt-pcr reaction from infected organs. | a single tube reverse transcription-polymerase chain reaction (rt-pcr) method for detection of african horse sickness virus (ahsv) in splenic tissues from infected horses is described. double stranded rna was extracted from infected organs of horses and used to produce complementary dna (cdna) with the two primers selected for the pcr. the 1179 bp amplified product (the segment 7 which encodes for vp 7), detected by electrophoresis on agarose gel and ethidium bromide staining, was hydrolysed wit ... | 1994 | 8188813 |
| development of a nested-pcr test based on sequence analysis of epizootic hemorrhagic disease viruses non-structural protein 1 (ns1). | two orbiviruses, epizootic hemorrhagic disease (ehd) and bluetongue (btv) viruses, cause disease in domestic and wild ruminant species. the gene that encodes non-structural protein 1 (ns1) of ehd virus, serotype 1, was sequenced and compared to ehd and btv ns1 sequences. the ns1 gene was found to be more conserved than the vp3 gene, and was selected as a target for polymerase chain reaction (pcr) amplification. the ns1 genes of several btv viruses and another orbivirus, african horse sickness (a ... | 1994 | 8191788 |
| detection of african horse sickness virus by reverse transcription-pcr. | reverse transcription-pcr (rt-pcr) was used to detect african horse sickness virus (ahsv). a single primer pair which amplified a 423-bp fragment of the s8 gene which encodes the ns2 protein of ahsv was identified. amplification of this fragment from all nine serotypes of ahsv was achieved with these primers. between 10(1) and 10(2) copies of ahsv genomic double-stranded rna could be detected by rt-pcr followed by agarose gel electrophoresis and ethidium bromide staining. application of rt-pcr t ... | 1994 | 8195381 |
| 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 ... | 1994 | 7596566 |
| 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 ... | 1994 | 7863585 |
| 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 ... | 1994 | 7975880 |
| 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 ... | 1994 | 7979976 |
| 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 ... | 1994 | 7989441 |
| 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 ... | 1994 | 7996157 |
| 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 ... | 1994 | 8001348 |
| 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 ... | 1994 | 8001350 |
| 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 ... | 1994 | 8001351 |
| 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 ... | 1994 | 8002793 |
| 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 ... | 1994 | 8009847 |
| 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 ... | 1994 | 8046387 |
| 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. | 1994 | 8068745 |
| 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 ... | 1994 | 8075221 |
| 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 ... | 1994 | 8075225 |
| 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 ... | 1994 | 7501364 |
| 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. | 1994 | 7501371 |
| 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 ... | 1995 | 7539971 |
| 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 ... | 1995 | 7542417 |
| 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. | 1995 | 7543488 |
| 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 ... | 1995 | 7594620 |
| 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 ... | 1995 | 7595366 |
| 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 ... | 1995 | 7710356 |
| 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 ... | 1995 | 7741589 |
| 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 ... | 1995 | 7771050 |
| an amino-terminal polypeptide fragment of the influenza virus ns1 protein possesses specific rna-binding activity and largely helical backbone structure. | the ns1 protein of influenza a virus has the unique property of binding to three apparently different rnas: poly a; a stem-bulge in u6 small nuclear rna; and double-stranded rna. one of our major goals is to determine how the ns1 protein recognizes and binds to its several rna targets. as the first step for conducting structural studies, we have succeeded in identifying a fragment of the ns1 protein that possesses all the rna-binding activities of the full-length protein. the rna-binding fragmen ... | 1995 | 8548659 |
| the use of african horse sickness virus ns3 protein, expressed in bacteria, as a marker to differentiate infected from vaccinated horses. | segment 10 of the double-stranded rna (dsrna) genome from african horse sickness virus serotype 4 (ahsv-4) was cloned and sequenced. the sequence of the coding region showed a total length of 667 bp. nucleotide comparisons showed a 95% sequence similarity between serotypes 4 and 9, and 76% between serotypes 4 and 3. cdna clones containing the coding region were cloned in the vector pet3xb and expressed in escherichia coli. the ns3 gene product was synthesised at very high level as an insoluble f ... | 1995 | 8578859 |
| african horse sickness surveillance systems and regionalisation/zoning: the case of south africa. | central and southern africa are generally regarded as being endemic areas for african horse sickness (ahs). with the advent of the concepts of risk analysis and regionalisation/zoning, however, the possibility has now arisen of establishing 'zones' within south africa for ahs surveillance purposes. in 1993, a protocol was submitted to the european community (now european union: eu), proposing the establishment of an ahs-free zone in the cape peninsula. the proposal is based on historical evidenc ... | 1995 | 8593398 |
| african horse sickness and african carnivores. | african horse sickness (ahs) is a disease that affects equids, and is principally transmitted by culicoides spp. that are biological vectors of ahs viruses (ahsv). the repeated spread of ahsv from sub-saharan africa to the middle east, northern africa and the iberian peninsula indicate that a better understanding of ahs epizootiology is needed. african horse sickness has long been known to infect and cause mortality among domestic dogs that ingest virus contaminated meat, but it is uncertain wha ... | 1995 | 8604545 |
| workshop on the geographic spread of aedes albopictus in europe and the concern among public health authorities. proceedings of a workshop held at the istituto superiore di sanità, rome, italy, 19-20 december 1994. | 1995 | 8778669 | |
| 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 ... | 1995 | 7477018 |
| 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 ... | 1995 | 7494497 |
| 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 ... | 1995 | 7653106 |
| differentiation of african horse sickness viruses by polymerase chain reaction and segments 10 restriction patterns. | this paper describes a single tube reverse transcription-polymerase chain reaction (rt-pcr) method for detection of african horse sickness virus (ahsv). the genomic segments 10 of viruses of the 9 ahsv serotypes were amplified. the 758bp products were digested to completion by restriction enzymes. the restriction fragment length polymorphisms of segments 7 and 10 cdna allowed the differentiation of the nine serotypes. | 1995 | 8748551 |
| detection of bluetongue virus and african horsesickness virus in co-infected cell cultures with ns1 gene probes. | the serogroup specificity of the bluetongue virus (btv) ns1 and vp3 gene probes was confirmed by means of northern blot hybridization. under high-stringency conditions both probes hybridized to 22 btv serotypes (18 south african serotypes, btv3 from cyprus and btv16 from pakistan) but not to serotypes that originate from australia and india. furthermore, ns1 gene probes of btv and african horsesickness virus (ahsv) were used in a dot-spot in situ hybridization procedure to differentiate between ... | 1995 | 8668318 |
| epidemiology of african horsesickness: antibodies in free-living elephants (loxodonta africans) and their response to experimental infection. | the presence of low levels of group- and type-specific antibodies against african horsesickness virus in the serum of some free-living elephants was reconfirmed. experimental infection resulted in conflicting results. no detectable viraemia nor virus could be demonstrated in the organs of the six elephant calves and none of them mounted significant levels of neutralizing antibodies against the virus. on the other hand, all calves showed a slight rise in elisa titres. this rise, however, was mode ... | 1995 | 8668325 |
| full protection against african horsesickness (ahs) in horses induced by baculovirus-derived ahs virus serotype 4 vp2, vp5 and vp7. | african horsesickness virus serotype 4 (ahsv-4) outer capsid protein vp2, or vp2 and vp5 plus inner capsid protein vp7, derived from single or dual recombinant baculovirus expression vectors were used in different combinations to immunize horses. when the proteins were purified by affinity chromatography, the combination of all three proteins induced low levels of neutralizing antibodies and conferred protection against virulent virus challenge. however, purified vp2 or vp2 and vp5 in the absenc ... | 1996 | 8683209 |
| detection and differentiation of epizootic haemorrhagic disease of deer and bluetongue viruses by serogroup-specific sandwich elisa. | a serogroup specific sandwich elisa was developed for the detection of epizootic haemorrhagic disease of deer viruses (ehdv) in infected insects and tissue culture preparations. polyclonal rabbit antiserum against purified ehdv core particles was used to capture viral antigen and specific binding detected using guinea pig antisera against ehdv core particles followed by anti-guinea pig immunoglobulin enzyme-labelled conjugate. the assay is ehdv specific and detects all 8 serotypes. no cross-reac ... | 1996 | 8690767 |
| characterization of the gene encoding core protein vp6 of two african horsesickness virus serotypes. | the genes encoding the inner core protein vp6 of african horsesickness virus (ahsv) serotypes 3 and 6 have been cloned and sequenced. the genes are 1169 nucleotides in length and both encode a largely hydrophilic protein of 369 amino acids. the vp6 amino acid sequence is highly conserved between the two serotypes with an overall similarity of 95 percent. comparison of the ahsv vp6 amino acid sequences with those of bluetongue virus serotype 10 vp6 revealed that it is 41 amino acids longer with a ... | 1996 | 8757982 |
| a blocking elisa for detection of antibody to a subgroup-reactive epitope of african horsesickness viral protein 7 (vp7) using a novel gamma-irradiated antigen. | a novel gamma irradiated inactivated cell culture derived african horsesickness viral (ahsv) antigen was used in a blocking elisa (b-elisa) for detecting antibody to a subgroup-reactive epitope of ahsv. a monoclonal antibody (mab), class igm, against an epitope on african horsesickness (ahs) viral protein 7 (vp7) was developed in balbc mice and used in the b-elisa. the mab, designated f9h, was blocked by 69 serums from equidae with antibody to ahs, but its binding activity was not appreciably af ... | 1996 | 8784514 |
| recombinant baculovirus-synthesized african horsesickness virus (ahsv) outer-capsid protein vp2 provides protection against virulent ahsv challenge. | african horsesickness virus serotype 4 (ahsv-4) outer-capsid proteins vp2 or vp2 and vp5, prepared from single or dual recombinant baculovirus expression vectors grown in sf9 insect cells, were administered in different amounts to horses and the neutralizing antibody responses were measured. control and vaccinated horses were challenged with virulent ahsv-4 6 months later and monitored post challenge. the results indicated that two inoculations of extracts containing vp2 and vp5, or vp2 alone, i ... | 1996 | 8811002 |
| role of dogs (canis domesticus) as hosts for african horse sickness virus. | at bet dagan culicoides imicola kieffer, c. schultzei gp. (a mammal feeder), culex pipiens l. (a laboratory vector) and culex univittatus theobald were found in significantly (p < 0.05) smaller numbers near dogs than near other hosts, while phlebotomus spp. were found in significantly (p < 0.05) higher numbers in dog kennels than in other animal houses. some 400 blood meals of culicoides spp. from israel and zimbabwe were negative for canine blood. only 1 of 16 blood meals of culex pipiens caugh ... | 1996 | 8828119 |
| subcellular localization of the nonstructural protein ns3 of african horsesickness virus. | the subcellular localization of the minor nonstructural protein ns3 of african horsesickness virus (ahsv) has been investigated by means of immunogold electron-microscopical analysis. ns3 was observed in perturbed regions of the plasma membrane of ahsv-infected vero cells, and its presence appears to be associated with events of viral release. these events are budding, whereby released viruses acquire fragments from the host-cell membrane, as well as by the extrusion of nonenveloped particles th ... | 1996 | 8848304 |
| characterisation of wongorr virus, an australian orbivirus. | sequence analyses of vp3 gene segments of wongorr virus isolates from the northern territory of australia were compared with the cognate gene segments from picola and paroo river viruses. previous serological investigations had demonstrated some relationships between these viruses, however vp3 gene sequence and phylogenetic analyses placed these viruses within the same serogroup which was distinct from other described orbivirus serogroups. a polymerase chain reaction (pcr) was developed for the ... | 1996 | 8879140 |
| crystal structure of the top domain of african horse sickness virus vp7: comparisons with bluetongue virus vp7. | the baculovirus-expressed core protein vp7 of african horse sickness virus serotype 4 (ahsv-4) has been purified to homogeneity and crystallized in the presence of 2.8 m urea. the x-ray structure has been solved to a 2.3-angstroms (1 angstrom = 0.1 nm) resolution with an rfactor of 19.8%. the structure of ahsv vp7 reveals that during crystallization, the two-domain protein is cleaved and only the top domain remains. a similar problem was encountered previously with bluetongue virus (btv) vp7 (wh ... | 1996 | 8648715 |
| immunization with vp2 is sufficient for protection against lethal challenge with african horsesickness virus type 4. | horses were immunized by inoculation with a vaccinia construct containing a full-length cdna corresponding to the l2 gene segment of african horsesickness virus type 4(ahsv-4). all immunized horses developed serum neutralizing antibodies prior to challenge with virulent ahsv-4. no elisa-reactive antibodies were present prior to challenge. a group of four seronegative control horses died after developing clinical signs and lesions typical of the pulmonary form of african horsesickness while the i ... | 1996 | 8659117 |
| a potential proline-rich motif upstream of the immunoreceptor tyrosine-based activation motif in bovine leukemia virus gp30, epstein-barr virus lmp2a, herpesvirus papio lmp2a, and african horsesickness virus vp7. | 1996 | 8661376 | |
| a novel cellular site-specific dna-binding protein cooperates with the viral ns1 polypeptide to initiate parvovirus dna replication. | replication of linear single-stranded parvovirus dna proceeds by a rolling-hairpin mechanism which generates long, palindromic, duplex concatamers. processing to monomer length requires initiation from origins of dna replication located at the 3' and 5' ends of each embedded monomer, reactions which can be recapitulated in vitro for minute virus of mice (mvm). to determine which cellular proteins were essential for replication from these origins, s100 extracts from 293s cells were fractionated o ... | 1997 | 8995666 |
| serologic markers in early stages of african horse sickness virus infection. | fifteen horses were experimentally infected with african horse sickness virus (ahsv) serotype 4. to learn more about the time course of production and specificity of ahsv-specific antibodies, sera were analyzed by immunoblot analysis. only animals that survived for more than 9 days were able to develop a humoral immune response detectable by immunoblotting. the earliest serological markers corresponded mainly to vp5, vp6, and ns2 and to a lesser extent to vp3, ns1, and ns3. neutralizing antibodi ... | 1997 | 9003637 |
| comparative sequence analysis and expression of the m6 gene, encoding the outer capsid protein vp5, of african horsesickness virus serotype nine. | the entire nucleotide and deduced amino acid sequence of the m6 gene of african horsesickness virus (ahsv) serotype nine has been determined from four overlapping cdna clones. the gene was found to be 1566 bp long, encoding a protein of 505 amino acids with a molecular weight of 56 737 da and a nett charge of - 1 at neutral ph comparative sequence analysis of the deduced amino acid sequence with the vp5 protein of ahsv-4, showed that only 81% of amino acids were conserved in type and position, a ... | 1997 | 9037735 |
| transmission and distribution of virus serotypes: african horse sickness in zebra. | the prevalence of african horse sickness (ahs) serotypes in zebra foals from the kruger national park, south africa was examined for possible associations between serotypes and to estimate the basic reproduction number, r0. the distributions of serotypes between zebra were not independent in the 6- and 7-8-month-old age classes (p < 0.005). this does not necessarily imply biological interactions between serotypes, as heterogeneity in host-vector transmission rates can generate non-independent di ... | 1997 | 9042034 |
| spatial and seasonal distribution of culicoides imicola in iberia in relation to the transmission of african horse sickness virus. | collections of biting midges were made over 24 months from sixty sites spread across iberia. information on the distribution of the vector of african horse sickness virus, culicoides imicola, from these 3119 samples showed that this species was annually present across south-western spain as far as 3 degrees 53'w and throughout most of portugal, up to 41 degrees 5'n. c. imicola was found in all areas where african horse sickness epizootics had occurred in 1987-90 and also in areas outside the epi ... | 1997 | 9061677 |
| characterization of tubular structures composed of nonstructural protein ns1 of african horsesickness virus expressed in insect cells. | the characteristic tubules that are produced during the orbivirus infection cycle are composed of a major viral nonstructural protein, ns1. to characterize the ns1 gene and gene product of african horsesickness virus (ahsv), a full-length cdna copy of the ns1 gene of ahsv-6 was cloned and the nucleotide sequence determined. ns1 was highly conserved within the ahsv serogroup with between 95-98% conservation of amino acids among ns1 of ahsv-6, ahsv-4 and ahsv-9. the structure of ahsv ns1 tubules w ... | 1997 | 9152425 |
| nucleotide sequence comparison of the segments s10 of the nine african horsesickness virus serotypes. | segments 10 (s10) of the double-stranded rna (ds rna) genomes from african horsesickness virus (ahsv) serotypes 2, 4, 5, 6 and 7 were cloned and sequenced. direct sequencing of previously reverse transcribed amplified (rt)-pcr segments s10 was also performed. nucleotide sequences of two strains (the virulent moroccan strain and a vaccine strain) of the same serotype (4) were determined. sequences of the viral serotypes were analysed and compared to each other. two in-phase atg codons were conser ... | 1997 | 9191861 |
| african horsesickness virus vp7 sub-unit vaccine protects mice against a lethal, heterologous serotype challenge. | an established mouse model was used to evaluate the effectiveness of the major outer core protein of african horsesickness virus (ahsv), vp7, as a subunit vaccine. adult female balb/c mice were immunized with vp7 crystals purified from bhk cells infected with ahsv serotype 9 (ahsv-9), using three inoculations in freund's adjuvant. eighty to one hundred per cent of the immunized mice were protected against a heterologous challenge with a known lethal dose of ahsv-7. the protected immunized mice d ... | 1997 | 9225037 |
| detection of african horse sickness virus in the blood of experimentally infected horses: comparison of virus isolation and a pcr assay. | a reverse transcription-polymerase chain reaction (rt-pcr) assay followed by dot-blot hybridisation was used to detect african horse sickness virus (ahsv); the primers employed amplified the s7 gene that encodes the vp7 protein. the rt-pcr assay was compared with virus isolation for detecting ahsv in blood samples form horses experimentally infected with ahsv-4 and ahsv-9. the influence of sample storage and transportation and the effects of two anticoagulants (edta and heparin) were also studie ... | 1997 | 9300539 |
| the spatial and seasonal distribution of african horse sickness and its potential culicoides vectors in morocco. | african horse sickness (ahs) is a vector-borne, infectious disease of equines that is caused by african horse sickness virus (ahsv). the only proven field vector is the biting midge culicoides imicola, although c. obsoletus and c. pulicaris are suspected vectors. there was a recent epizootic of ahs in iberia (1987-90) and morocco (1989-91). in 1994-45 a total of 3887 light trap samples were taken from twenty-two sites distributed over most of morocco. culicoides imicola was found to be very wide ... | 1997 | 9330250 |
| effects of domain-switching and site-directed mutagenesis on the properties and functions of the vp7 proteins of two orbiviruses. | based on the crystal structure of the vp7 major core protein of bluetongue virus serotype 10 (btv-10) and that of the top domain of the vp7 protein of african horsesickness virus serotype 4 (ahsv-4), chimeras and site-directed mutants of the proteins were constructed and the products analyzed with respect to their properties and functions. chimeras with the central upper domain of btv-10 vp7 replaced by that of ahsv-4 vp7 (construct bab) formed trimers, as did the converse construct (aba). furth ... | 1997 | 9356334 |
| immunohistochemical demonstration of african horse sickness viral antigen in formalin-fixed equine tissues. | the distribution of viral antigen was studied in various tissues of three ponies, aged 3-4 years, infected experimentally with a virulent strain of african horse sickness virus (ahsv) serotype 4. tissues were collected from the animals in the terminal stage of the peracute form of the disease and from one noninfected horse, included as a control. a polyclonal antibody with specificity for ahsv, plus the nonstructural protein ns2, was used in a sensitive avidin-biotin-peroxidase-complex (abc) met ... | 1997 | 9396137 |
| 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 |
| the complete sequence of four major structural proteins of african horse sickness virus serotype 6: evolutionary relationships within and between the orbiviruses. | the amino acid sequences of four major capsid proteins of african horse sickness virus (serotype 6, ahsv-6) have been determined from analyses of cdna clones representing the l2, l3, m6 and s7 rna segments. the ahsv-6 l3 rna segment has an open reading frame of 2715 base pairs and encodes the inner capsid protein vp3 which comprises 905 amino acids. the vp3 layer forms the subcore of the virion and is surrounded by the vp7 protein which is encoded by the s7 gene. the ahsv-6 s7 gene was found to ... | 1998 | 9617769 |
| culicoides in relation to transmission of african horse sickness virus in the gambia. | twelve light trap collections made near overnight shelters of horses and donkeys in four villages in the central river division of the gambia captured fourteen species of biting midge of the genus culicoides. five species new to the gambia were identified. this brought the number of recognized species of culicoides (after a revision of c. schultzei) to twenty-nine in the gambia. species known or suspected as vectors of african horse sickness virus (ahsv) and bluetongue virus (btv) comprised 83% ... | 1998 | 9622369 |
| detection of african horsesickness virus and discrimination between two equine orbivirus serogroups by reverse transcription polymerase chain reaction. | a reverse transcription polymerase chain reaction (rt-pcr), based on the gene encoding the ns2 protein of african horsesickness virus (ahsv), was developed for rapid serogroup-specific detection of ahsv. the specificity of rt-pcr products was confirmed by southern blot hybridization using a radioactively labelled cdna probe specific for the ns2 gene. this rt-pcr could discriminate between all known members of the ahsv and equine encephalosis virus serogroups. ahsv rna was detected in a sample re ... | 1998 | 9629584 |
| sequence-independent amplification and cloning of large dsrna virus genome segments by poly(da)-oligonucleotide ligation. | a strategy was developed for sequence-independent synthesis and amplification of full-length cdna of 3-4 kb genes of dsrna viruses. the method of single primer amplification (lambden et al., 1992) was adapted by the inclusion of a 3' poly(a) tail to an oligonucleotide ligated to dsrna genome segments as a template for oligo(dt)-primed cdna synthesis. full-length copies of the largest genome segments, 1 (4 kb) and 2 (3 kb), of african horse sickness virus (ahsv) have been cloned, terminally seque ... | 1998 | 9694332 |
| use of climatic data and satellite imagery to model the abundance of culicoides imicola, the vector of african horse sickness virus, in morocco. | african horse sickness (ahs) is a vector-borne, infectious disease of equids caused by african horse sickness virus (ahsv). the only proven field vector of the virus is the biting midge culicoides imicola. following a recent epizootic (1989-91) of ahs in morocco, light traps and automatic weather stations were operated for 2 years at twenty-two sites distributed over much of the country. the annually-averaged mean daily trap catch of c. imicola at these sites was negatively correlated with wind ... | 1998 | 9737597 |
| 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 |
| transmission and distribution of african horse sickness virus serotypes in south african zebra. | the prevalences of african horse sickness (ahs) virus serotypes in zebra foals from the kruger national park, south africa were examined for possible associations between serotypes. serotypes known to cross-react were combined for analysis. the distributions of serotypes between zebra were not always independent; in 7-8 month old zebra positive pairwise associations were observed between 3 serotypes. this could be generated by biological interactions between serotypes or heterogeneity in host-ve ... | 1998 | 9785492 |
| serological and virological responses in mules and donkeys following inoculation with african horse sickness virus serotype 4. | two groups, comprising 4 donkeys and 4 mules (group 1) and 4 donkeys and 3 mules (group 2), were used to determine the duration of viraemia and to monitor the development of antibodies following inoculation with african horse sickness virus (ahsv). one group of animals was given a single dose of attenuated ahsv serotype 4 (ahsv 4) vaccine. the second group was inoculated with a virulent field strain of ahsv 4. both groups were subsequently challenged with the virulent field strain of ahsv 4, 51 ... | 1998 | 9785493 |
| donkeys as reservoirs of african horse sickness virus. | investigations have been carried out to elucidate the possible role of the donkey in the epidemiology of african horse sickness (ahs). these studies have shown that despite the absence of pyrexia or other observable clinical signs, donkeys become infected with virulent ahs virus serotype 4 (ahsv 4) and that they develop a viraemia which can persist for at least 12 days, albeit at a comparatively lower titre than that recorded for similarly infected ponies. ahsv 4 showed a similar tissue tropism ... | 1998 | 9785494 |
| clinical, virological and immune responses of normal and immunosuppressed donkeys (equus asinus africanus) after inoculation with african horse sickness virus. | to elucidate the role that donkeys may play in african horse sickness virus (ahsv) persistence during inter-epizootic periods we looked for clinical signs of infection and studied the viraemia and neutralising antibody kinetics in 3 immunocompetent and 3 immunosuppressed donkeys inoculated with ahsv-4. none of the donkeys developed signs of ahs. however infectious ahsv was isolated from the blood of the immunocompetent donkeys for up to 17 days post infection (dpi) and viral antigens were detect ... | 1998 | 9785495 |
| immunohistochemical demonstration of african horse sickness viral antigen in tissues of experimentally infected equines. | african horse sickness virus (ahsv) antigen was demonstrated immunohistochemically in formalin-fixed, paraffin-embedded sections of tissues collected from three ponies suffering from the peracute form of the disease and from one pony affected by the fever form. the pattern of the antigen distribution indicated a particular organ tropism characterised by an accumulation of ahsv antigen in cardio-pulmonary tissues of the animals with the peracute disease and in the spleen of the pony with the feve ... | 1998 | 9785496 |
| 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 |