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1.
A silent cycle of equine herpesvirus 1 infection was described following epidemiological studies of unvaccinated mares and foals on a Hunter Valley stud farm. Following the introduction of routine vaccination with an inactivated whole virus equine herpesvirus 1 (EHV-1) and equine herpesvirus 4 (EHV-4) vaccine in 1997, a subsequent study identified excretion of EHV-1 and EHV-4 in nasal swab samples tested by PCR from vaccinated mares and their unweaned, unvaccinated foals. The current sero-epidemiological investigation of vaccinated mares and their young foals found serological evidence of EHV-1 and EHV-4 infection in mares and foals in the first 5 weeks of life. The results further support that EHV-1 and EHV-4 circulate in vaccinated populations of mares and their unweaned foals and confirms the continuation of the cycle of EHV-1 and EHV-4 infection.  相似文献   

2.
The prevalence of EHV-1 and EHV-4 antibody-positive horses was determined using a type specific ELISA on serum samples collected from 229 mares and their foals resident on a large Thoroughbred stud farm in the Hunter Valley of New South Wales in February 1995. More than 99% of all mares and foals tested were EHV-4 antibody positive, while the prevalence of EHV-1 antibody positive mares and foals were 26.2 and 11.4%, respectively. Examination of the ELISA absorbance data for the individual mares and foals suggested that the EHV-1 antibody positive foals had been infected recently with EHV-1 and that a sub-group of the mare population was the likely source of infectious virus for the unweaned foals.  相似文献   

3.
Fifteen unweaned thoroughbred foals, born on a stud farm to vaccinated mares, were clinically monitored during their first six months of life and repeatedly tested for equine herpesvirus type 1 (EHV-1) and equine herpesvirus type 4 (EHV-4). Nasopharyngeal swabs and blood samples were collected and screened respectively by PCR and seroneutralisation to detect the presence of the virus, explore its role as a possible cause of respiratory disease, and to assess the efficiency of the pcr for the diagnosis of this disease. The foals were divided into three groups on the basis of their clinical signs and whether they had seroconverted to EHV-1 and/or EHV-4: first, foals with no clinical signs of disease that had not seroconverted; secondly, foals with clinical signs that had seroconverted, and thirdly, foals with clinical signs that had not seroconverted. The results indicated that the viruses circulated on the stud farm despite stringent vaccination regimens against them, and confirmed their association with respiratory disease. The absence of significantly different pcr results among the three groups of foals showed that the pcr was effective in confirming the circulation of the viruses on the premises without being particularly helpful as a diagnostic tool.  相似文献   

4.
Sero-epidemiological studies conducted between 1995 and 1997 on two large Thoroughbred stud farms in the Hunter Valley of NSW showed clear evidence of EHV-1 infection in foals as young as 30 days of age. Similarly, serological evidence suggested that these foals were infected with EHV-1 from their dams or from other lactating mares in the group, with subsequent foal to foal spread of infection prior to weaning. These studies also provided evidence of EHV-1 infection of foals at and subsequent to weaning, with foal to foal spread of EHV-1 amongst the weanlings. These data indicated that the mare and foal population was a reservoir of EHV-1, from which new cases of infection propagated through the foal population both before and after weaning. The results of these studies support the long standing management practices of separating pregnant mares from other groups of horses to reduce the incidence of EHV-1 abortion. Also, these results have important implications for currently recommended vaccination regimens, as the efficacy of vaccination in already latently infected horses is unknown.  相似文献   

5.
Equine herpesvirus type 1 and type 4 (EHV-1 and EHV-4) cause infections of horses worldwide. While both EHV-1 and EHV-4 cause respiratory disease, abortion and myeloencephalopathy are observed after infection with EHV-1 in the vast majority of cases. Disease control is achieved by hygiene measures that include immunization with either inactivated or modified live virus (MLV) vaccine preparations. We here compared the efficacy of commercially available vaccines, an EHV-1/EHV-4 inactivated combination and an MLV vaccine, with respect to induction of humoral responses and protection of clinical disease (abortion) in pregnant mares and foals on a large stud with a total of approximately 3500 horses. The MLV vaccine was administered twice during pregnancy (months 5 and 8 of gestation) to 383 mares (49.4%), while the inactivated vaccine was administered three times (months 5, 7, and 9) to 392 mares (50.6%). From the vaccinated mares, 192 (MLV) and 150 (inactivated) were randomly selected for serological analyses. There was no significant difference between the groups with respect to magnitude or duration of the humoral responses as assessed by serum neutralization assays (median range from 1:42 to 1:130) and probing for EHV-1-specific IgG isotypes, although neutralizing responses were higher in animals vaccinated with the MLV preparation at all time points sampled. The total number of abortions in the study population was 55/775 (7.1%), 9 of which were attributed to EHV-1. Seven of the abortions were in the inactivated and two in the MLV vaccine group (p=0.16). When foals of vaccinated mares were followed up, a dramatic drop of serum neutralizing titers (median below 1:8) was observed in all groups, indicating that the half-life of maternally derived antibody is less than 4 weeks.  相似文献   

6.
A German abortion isolate of EHV-1 (strain M8) was grown in equine dermal (ED) cells at a low multiplicity of infection in presence of 5-bromo-2-deoxy uridine. The resulting stock was dialysed, titrated and cloned by terminal dilution in ED cells grown in 96-well microtitration plates. Of 192 clones each originating from a single focus, clone 147 (C147) was found to be restricted for growth at and above temperatures of 38.5 degrees C. It was also restricted for growth at 37 degrees C in rabbit kidney (RK-13) cells which are widely used for the isolation and titration of EHV-1; hence clone 147 was EHV-4-like.Clone 147 showed a remarkable efficacy as a vaccine in protecting conventional pregnant Welsh Mountain pony mares against abortions due to EHV-1. A single intranasal (IN) vaccination protected five out of six (83.3%), and four out of five (80%) of mares upon challenge 4 and 5-6 months, respectively, after the immunisation, whereas all six unvaccinated mares aborted between 9 and 19 days after IN EHV-1 challenge. With the exception of the day 9 abortion, foetuses of the remaining five mares were EHV-1 infected. Placenta from the early aborting mare was, however, EHV-1 positive. Both groups of vaccinated mares were also significantly protected against clinical reaction (notably pyrexia), nasal shedding and viraemia following challenge infection.  相似文献   

7.
OBJECTIVE: To determine the incidence of equine herpesvirus-1 (EHV-1) infection among Thoroughbreds residing on a farm on which the virus was known to be endemic. DESIGN: Prospective cohort study. ANIMALS: 10 nonpregnant mares, 8 stallions, 16 weanlings, 11 racehorses, and 30 pregnant mares and their foals born during the 2006 foaling season. PROCEDURES: Blood and nasopharygeal swab samples were collected every 3 to 5 weeks for 9 months, and placenta and colostrum samples were collected at foaling. All samples were submitted for testing for EHV-1 DNA with a PCR assay. A type-specific EHV-1 ELISA was used to determine antibody titers in mares and foals at birth, 12 to 24 hours after birth, and every 3 to 5 weeks thereafter. RESULTS: Results of the PCR assay were positive for only 4 of the 1,330 samples collected (590 blood samples, 590 nasopharyngeal swab samples, 30 placentas, and 30 colostrum samples), with EHV-1 DNA detected in nasal secretions from 3 horses (pregnant mare, stallion, and racehorse) and in the placenta from 1 mare. Seroconversion was detected in 3 of 27 foals during the first month of life. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that there was a low prevalence of EHV-1 infection among this population of Thoroughbreds even though the virus was known to be endemic on the farm and that pregnant mares could become infected without aborting. Analysis of nasopharyngeal swab samples appeared to be more sensitive than analysis of blood samples for detection of EHV-1 DNA.  相似文献   

8.
Objective To investigate the seroprevalence of equine herpesvirus 1 in foals around weaning and after weaning on two large Thoroughbred farms using a type-specific enzyme-linked immunosorbent assay to determine exposure to infection.
Design A longitudinal population study in groups of Thoroughbred weanling foals.
Study population Two hundred weanling Thoroughbred foals from a population of about 380 foals were enrolled on two adjacent stud farms in the Hunter Valley of New South Wales. Foals on both farms were weaned from February to May 1995 into randomly selected groups of 10 to 15 foals. Farms were selected because of their willingness to cooperate in the survey and because their detailed records of foals and their movements. They were representative of well-managed large Thoroughbred stud farms in New South Wales. Both studs had upper respiratory tract disease among weanling foals around weaning each year although the sero-prevalence of viral respiratory disease on either farm was not known before the study.
Procedure Serum was collected from foals within each group at fortnightly intervals from 9th February until 1st June 1995, and at a single follow-up period in August 1995. Each sample was tested in triplicate using an antibody-detection ELISA which is type-specific for EHV-1 and EHV-4 antibodies.
Results and conclusions There was serological evidence of EHV-1 infection both before and after weaning. The prevalence of EHV-1 antibody in the sample population increased during the study and individual cases of EHV-1 infection were identified. The increase was caused both by the seroconversion of foals within the groups and by the recruitment into the study of foals with pre-existing EHV-1 antibody. Evidence of EHV-1 infection in Thoroughbred foals after weaning has not been reported previously in Australia and this has implications for vaccination regimens.  相似文献   

9.
OBJECTIVE: To examine the prevalence of equine herpesvirus 1 antibody in mares and foals on a large Hunter Valley Thoroughbred stud farm in New South Wales before and after the introduction of an inactivated whole virus vaccine. DESIGN: Cross-sectional serological surveys performed in February 1995 and 2000 to determine the prevalence of EHV-1 antibody-positive mares and foals. A further cross-sectional survey was carried out in 2001 to complement the 2000 data. STUDY POPULATION: Two hundred and twenty-nine mares and their foals were sampled in 1995 and 236 mares and their foals were sampled in 2000. The study population comprised all of the mares with foals at foot on this property at each sample period. Fifty mares were sampled in both studies. A further 264 mares and their foals were sampled in 2001. PROCEDURE: A blood sample was collected from each mare and foal at the beginning of February 1995, 2000 and 2001. Each sample was tested in triplicate using an antibody-detection ELISA that is type-specific for EHV-1 and EHV-4 antibodies. RESULTS: The prevalence of EHV-1 antibody-positive mares was not statistically different in 2000 compared to 1995. However, the prevalence of antibody-positive foals was significantly lower in 2000 than in 1995. In 2001, the prevalence of antibody-positive mares was higher than in 2000, but not different from that in 1995. The prevalence of antibody-positive foals in 2001 was not significantly different from the prevalence observed in 1995 or that observed in 2000. However, when the three studies were compared there was a significant variation in the prevalence of EHV-1 positive foals due to the variation between the 1995 and the 2000 data. CONCLUSIONS: Mares are the source of virus from which foals are infected early in life and following analysis of the 2001 data, the difference in the prevalence of EHV-1 antibody-positive foals between 1995 and 2000 was likely to be a reflection of seasonal, nutritional and management factors, rather than the result of vaccination.  相似文献   

10.
REASONS FOR PERFORMING STUDY: An assay has been developed that measures EHV-1 specific interferon gamma synthesis (IFNgamma), a cytokine produced following the activation of memory T lymphocytes and therefore a measure of cell mediated immunity. The method requires validation in the field. OBJECTIVES: To measure the frequency of EHV-1 specific, IFNgamma synthesising peripheral blood mononuclear cells (PBMC) in a population of Thoroughbred horses, and examine its relationship with age, gender, premises and history of vaccination or field infection with EHV-1. METHODS: Lymphocytes from 200 Thoroughbred horses were stimulated with EHV-1 in vitro, and IFNgamma detected using a monoclonal antibody and indirect immunofluorescence. Percent positive cells were enumerated by flow cytometric analysis and the results described and compared statistically between groups. RESULTS: The frequency of IFNgamma+ PBMC was significantly higher in animals age >5 years compared with 2-4 years, in females vs. males, on stud farms vs. training yards and following vaccination of 2-year-olds with inactivated virus compared with nonvaccinates. Age strongly confounded all these associations and care must therefore be taken interpreting these results. Mares exposed to a field infection with EHV-1 also had higher frequencies of IFNgamma+ PBMC than other vaccinated horses. CONCLUSIONS: The frequency of EHV-1 specific, IFNgama+ PBMC among the sample Thoroughbred population was diverse but lowest in young, unvaccinated horses-in-training. POTENTIAL RELEVANCE: The frequency of EHV-1 specific lymphocytes synthesising IFNgamma in this population may be associated with its susceptibility to infection with this virus. This easy technique may be applied to monitor the antigenicity of vaccines and their effectiveness at stimulating cellular immunity.  相似文献   

11.
Thirty-three of the 44 mares on a Thoroughbred stud in New South Wales aborted or lost foals within one day of birth. Gross pathological and histological changes were in keeping with Equid herpesvirus I (EHV-1) abortion. In the six foals that underwent virological examination, EHV was isolated and typed as EHV-1 by restriction endonuclease analysis. EHV-1 abortion had not occurred previously on this stud and the source of the infection was not identified.  相似文献   

12.
Five of 10 pregnant, lactating mares, each with a foal at foot, developed neurological disease. Three of them became recumbent, developed complications and were euthanased; of the two that survived, one aborted an equine herpesvirus type 1 (EHV-1)-positive fetus 68 days after the first signs were observed in the index case and the other gave birth to a healthy foal on day 283 but remained ataxic and incontinent. The diagnosis of EHV-1 myeloencephalitis was supported by postmortem findings, PCR identification of the virus and by serological tests with an EHV-1-specific ELISA. At the time of the index case, the 10 foals all had a heavy mucopurulent nasal discharge, and PCR and the ELISA were used to detect and monitor EHV-1 infection in them. The status of EHV-1 infection in the five in-contact mares was similarly monitored. Sera from three of the affected mares, taken seven days after the index case were negative or had borderline EHV-1-specific antibody titres. In later serum samples there was an increase in the titres of EHV-1-specific antibody in two of the affected mares. In contrast, sera from the five unaffected in-contact mares were all EHV-1-antibody positive when they were first tested seven or 13 days after the index case.  相似文献   

13.
Six cases of paresis occurred in a Swedish stud with 48 mares and a stallion. Complement-fixation tests revealed a recent infection with EHV-1 in most horses of the stud. Serumneutralisation tests showed rapid antibody-titre increases during the course of the disease. This type of antibody response was interpreted as induced by reinfection or, possibly, recurrent infection. Two diseased mares were sacrificed. No virus could be isolated from their central nervous system (CNS), liver or spleen, but there is a presumptive evidence for the presence of an antigen specific to EHV-1 in the CNS and liver. Neutralising antibodies to EHV-1 were demonstrated in the liver and kidneys following elution by acidification of the tissues. No such antibodies could be demonstrated in the brain and spinal cord. A possible reason for this failure is discussed.  相似文献   

14.
Equine herpesvirus type 1 (EHV-1) is a worldwide spread pathogen of horses. It can cause abortion, respiratory and neurological disease and consequentially significant economic losses in equine industries. During 2009, two outbreaks of EHV-1 were confirmed in two stud farms in Eastern Croatia. The first outbreak occurred in February following the import of 12 horses from USA, serologically negative to EHV-1 before transport. Four mares aborted in the late stage of pregnancy and one perinatal death was recorded. Other six mares showed clinical signs of myeloencephalopathy with fatal end in four. One month later, the second EHV-1 outbreak was confirmed in stud farm about 100 km further with 17 abortions, three perinatal deaths and one mild neurological case. Epidemiological data showed that the disease was probably introduced in the first stud farm during international transport. The second outbreak started with the introduction of clinically healthy stallion from the first stud farm. Molecular characterisation and phylogenetic analysis confirmed that, despite different clinical signs, the identical virus caused both outbreaks. Both horse populations were free from EHV-1 infection before the outbreak and had not been vaccinated. Significant difference in clinical signs could be explained by different breed-related risk factors.  相似文献   

15.
In 1988 an outbreak of the paralytic form of Equid herpesvirus type 1 (EHV-1) infection occurred on a stud farm and several animals died. This provided an opportunity to perform detailed pathological investigations to gain insights into the pathogenesis of this spontaneous disease. Two paretic mares, three foals, an aborted foetus and its non-paretic dam were examined. The endotheliotropism of the virus was clearly demonstrated by the use of an indirect immunoperoxidase (IP) stain. At autopsy, evidence of viral infection was widespread in the foetus and foals, but limited or absent in the mares, probably reflecting differences in their immune status. Vascular lesions were present in the central nervous system (CNS) of the foals as well as the adults; they resulted in minimal neural lesions in the foals. Severe changes in the upper and lower respiratory tracts were a particular feature in the foals, two of which exhibited extensive vasculitis and thrombosis in the lungs. The IP technique was of great value in locating antigen-containing cells in the CNS of one mare when virus isolation was negative. It also revealed the presence of virus in less well documented sites such as the pancreas, gut, thyroid, uveal tract and the skin of the nares.  相似文献   

16.
The objectives of this study were to estimate the prevalence of equine herpesviruses (EHV) 1-5 in the nasal secretions (NS) of a cohort of 12 mares and their foals from birth to 6 months of age, estimate the prevalence of EHV-1-5 infection of peripheral blood mononuclear cells (PBMC) of selected foals, and investigate phylogenetic relationships amongst the various strains of EHV-2 and 5. Virus-specific PCR assays were used to detect EHV-1-5 in NS and PBMC. A homologous portion of the glycoprotein B (gB) gene of the various strains of EHV-2 and 5 was sequenced and compared. EHV-2, 4, and 5 were all detected in NS from the horses, but only EHV-4 was associated with respiratory disease (P=0.005). EHV-2 and 5 infections were both common, but foals shed EHV-2 in their NS earlier in life than EHV-5 (P=0.01). Latent EHV-2 and 5 infections were detected in the PBMC of 75 and 88%, respectively, of the foals at approximately 6 months of age. The strains of EHV-2 shed in the NS of individual horses were more genetically heterogeneous than the strains of EHV-5 (95.5-99.3% versus 98.8-99.3% nucleotide identity, respectively). One-month-old foals typically shed strains of EHV-2 that were identical to those infecting their dams whereas older foals often shed virus strains that were different from those of their dams. Although herpesvirus infections were ubiquitous in this cohort of horses, there were distinct clinical consequences and clear epidemiological differences between infections with the different viruses.  相似文献   

17.
AIMS: To identify the respiratory viruses that are present among foals in New Zealand and to establish the age at which foals first become infected with these viruses. METHODS: Foals were recruited to the study in October/ November 1995 at the age of 1 month (Group A) or in March/ April 1996 at the age of 4-6 months (Groups B and C). Nasal swabs and blood samples were collected at monthly intervals. Nasal swabs and peripheral blood leucocytes (PBL) harvested from heparinised blood samples were used for virus isolation; serum harvested from whole-blood samples was used for serological testing for the presence of antibodies against equine herpesvirus (EHV)-1 or -4, equine rhinitis-A virus (ERAV), equine rhinitis-B virus (ERBV), equine adenovirus 1 (EAdV-1), equine arteritis virus (EAV), reovirus 3 and parainfluenza virus type 3 (PIV3). Twelve foals were sampled until December 1996; the remaining 19 foals were lost from the study at various times prior to this date. RESULTS: The only viruses isolated were EHV-2 and EHV-5. EHV-2 was isolated from 155/157 PBL samples collected during the period of study and from 40/172 nasal swabs collected from 18 foals. All isolations from nasal swabs, except one, were made over a period of 2-4 months from January to April (Group A), March to April (Group B) or May to July (Group C). EHV-5 was isolated from either PBL, nasal swabs, or both, from 15 foals on 32 occasions. All foals were positive for antibodies to EHV-1 or EHV-4, as tested by serum neutralisation (SN), on at least one sampling occasion and all but one were positive for EHV-1 antibodies measured by enzyme-linked immunosorbent assay (ELISA) on at least one sampling occasion. Recent EHV-1 infection was evident at least once during the period of study in 18/23 (78%) foals for which at least two samples were collected. SN antibodies to ERBV were evident in 19/23 (83%) foals on at least one sampling occasion and 15/23 foals showed evidence of seroconversion to ERBV. Antibodies to ERAV were only detected in serum samples collected from foals in Group A and probably represented maternally-derived antibodies. Haemagglutination inhibition (HI) antibody titres 1:10 to EAdV-1were evident in 21/23 (91%) foals on at least one sampling occasion and 16/23 foals showed serological evidence of recent EAdV-1 infection. None of the 67 serum samples tested were positive for antibodies to EAV, reovirus 3 or PIV3. There was no clear association between infection with any of the viruses isolated or tested for and the presence of overt clinical signs of respiratory disease. CONCLUSIONS: There was serological and/or virological evidence that EHV-1, EHV-2, EHV-5, EAdV-1 and ERBV infections were present among foals in New Zealand. EHV-2 infection was first detected in foals as young as 3 months of age. The isolation of EHV-2 from nasal swabs preceded serological evidence of infection with other respiratory viruses, suggesting that EHV-2 may predispose foals to other viral infections.  相似文献   

18.
There has been an increase in outbreaks of neuropathogenic equine herpesvirus-1 (EHV-1) in the United States and Europe. However, the presence and frequency of neuropathogenic EHV-1 in Turkish horses are not known at present. This study aimed to investigate the frequency of EHV-1 and neuropathogenic strains of EHV-1 in the Marmara Region of Turkey. Samples were analyzed for the presence of EHV-1 and neuropathogenic EHV-1 by real-time PCR TaqMan probe assays. Overall detection rate of EHV-1 was 45.5% (51 of 112). The detection rates were 70.5% (24 of 34) in aborted fetuses, 53.3% (8 of 15) in neonatal deads, 66.6% (4 of 6) in foals, 40% (2 of 5) in dead mares, and 25% (13 of 52) in living mares. Overall detection rate of neuropathogenic EHV-1 was 7.8% (4 of 51), and the real-time PCR results were confirmed by sequencing. Neuropathogenic strains of EHV-1 were detected in the brain and lung of two mares with neurological disease but without a history of abortion, in the brain of a foal that died of respiratory disorder, and in the nasal swab from a mare with a history of abortion. On histopathology, nonpurulent meningoencephalitis, hemorrhages, and vasculitis were seen in the brain. In conclusion, results of this study indicated, for the first time, that the neuropathogenic EHV-1 is circulating in the Marmara Region of Turkey. The results of this study also show that the current risk for non-neuropathogenic strains is high, whereas risk for the neuropathogenic EHV-1-G2254 strain seems to be low. As outbreaks of EHV-1 continue in the Marmara region of Turkey, surveillance for neuropathogenic EHV-1 genotype should be maintained.  相似文献   

19.
In general, vaccines containing inactivated equine herpesvirus-1 (EHV-1) fail to prevent abortion in pregnant mares following infection with a virulent strain of EHV-1. We have tested the hypothesis that resistance to EHV-1-induced abortion in pregnant mares is associated with high frequencies of EHV-1 specific, major histocompatibility complex (MHC) class I-restricted, cytotoxic T lymphocytes (CTL) in the circulation. To test this theory, three groups of pregnant mares were assembled with varying backgrounds of infection or vaccination in an attempt to mimic the immune status of the general population. Group 1 mares (n=9) were untreated controls selected at random. Group 2 mares (n=5) were vaccinated three times intramuscularly with inactivated EHV-1. Group 3 mares (n=3) had been infected with EHV-1 on four previous occasions. The frequency of CTL in blood leucocytes was measured by limiting dilution analysis at three time points; at the beginning of pregnancy (approximately 28 weeks before infection) in the Group 2 and Group 3 mares (4-7 weeks of gestation) (Group 1 was unavailable for sampling) and then 2 weeks before (30-40 weeks of gestation) and 3 weeks after experimental infection in all the mares. Serum samples were collected to monitor complement fixing (CF) antibody titres. Mares in all three groups were infected experimentally with EHV-1 strain Ab4/8 by the intranasal route after which they were monitored clinically to determine the outcome of pregnancy and samples were collected to determine the duration of nasopharyngeal shedding and cell-associated viraemia. The untreated control mares showed low pre-infection CTL. After experimental infection, they all seroconverted, aborted and demonstrated expected clinical and virological signs. Some vaccinated mares (3/5) had elevated titres of CF antibody prior to their first vaccination. All the vaccinated mares seroconverted after vaccination and exhibited higher CTL frequencies than controls before infection. Four of the five foaled normally. The multiply infected mares had low CF antibody titres prior to infection and showed neither seroconversion nor clinical or virological signs after infection. All multiply infected mares exhibited high frequencies of CTL before infection and they all foaled normally. The CTL frequencies observed differed significantly from the expected frequencies in the control and multiply infected groups at 2 weeks pre-infection (P=0.034) and between the foaling and aborting mares at 2 weeks pre-infection (P=0.005) and 3 weeks post-infection (P=0.015). The results show a positive correlation between the number of virus-specific CTL in the peripheral blood of pregnant mares and their protection against abortion induced by EHV-1 infection. Therefore, as indicated by this study, rational approaches to the development of new vaccines for EHV-1 should stimulate cytotoxic immune responses and develop virus-specific CTL as pre-requisites for protection against abortion.  相似文献   

20.
The aim of the present study was to investigate abortion storms that occurred in the Marmara region of Turkey in 2008-2009 using a real-time PCR. Two aborted foetuses were necropsied and histo-pathological findings reported herein. Ten lungs, 3 brains and one nasal swab from 10 aborted foetuses, 6 nasal swabs and 3 vaginal swabs from aborting mares were included in this study. EHV-1 was isolated from the lung, liver and brain of 1 aborted foetus. EHV-1 DNA was detected in the lungs, livers and spleens of 2 necropsied foetuses and in 3 lungs from 10 foetuses submitted for diagnosis. A brain from one of the aborted foetuses was also positive for EHV-1 DNA. EHV-4 DNA was detected only in a nasal swab of one of the tested foetuses. Neither EHV-1 nor EHV-4 DNA was detected in the swabs of aborting mares. Sequence analysis of the glycoprotein B of the strains was performed and a phylogenetic tree was generated. The results indicated that 4 of the 5 Turkish EHV-1 strains (TR02, TR03, TR04 and TR05) clustered together; the fifth strain (TR01) was slightly removed from the group and clustered with other EHV-1 from various origins. Single nucleotide polyporphism (SNP in ORF30) associated with neuropathogenesis was not detected in any of the strains. At necropsy, sub-milier focal necrosis in the liver and spleen was observed. Microscopically, focal coagulation necrosis and marked eosinophilic intranuclear and intracytoplasmic inclusion bodies in the hepatocytes localised around the necrotic areas in the liver. Severe coagulation necrosis in white pulp of the spleen was also observed.  相似文献   

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