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1.
A group of 100 foals was given either a commercial bacterin or an autogenous vaccine consisting of whole cells and an acid extract of Streptococcus equi. During the study, some of the foals developed clinical strangles. Various sets of sera were collected from these foals prevaccination, during vaccination, postvaccination and postinfection. The serological response of these foals was measured by passive haemagglutination and long chain tests. In foals which remained healthy, the highest titres were reached within one to two months postvaccination with a passive haemagglutination 10 x log2 mean titre of 6.78 and the long chain indices of 4.41. These levels persisted for 120 days postvaccination. Those foals which had clinical strangles exhibited lower passive haemagglutination titres (3.78) at one to two months postimmunization, but rose significantly after recovery. Four ponies immunized with formalinized Str. equi bacterin showed a partial protection against the challenge infection. The passive haemagglutination titres, long chain indices and serum bactericidal activity in these ponies were highest at 35 days postvaccination but did not increase after infection. 相似文献
2.
Using the long chain test, and in some cases the bactericidal test, to measure antibody, the development of the immune response in horses to Str. equi has been followed. Long chain indices in excess of 5.0, accompanied by strong bactericidal capacity, were recorded in serums after the full 3-dose immunisation course with a commercial vaccine. The full course elicited the most satisfactory antibody titres declined within the 12 month post-vaccination period, thus providing support for the recommendation that yearly booster doses should be administered. The immune response in horses during 2 strangles outbreaks was compared with the response following vaccination. Recovered animals showed declining antibody levels 9 weeks after infection, and the evidence does not support longevity of the immune response after natural infection. Reaction to vaccination was observed in those animals with high initial antibody titre. 相似文献
3.
In this study, to evaluate the influence of strangles vaccination on serological test
results, we investigated the changes in strangles serum antibody levels in horses after
vaccination and subsequent intranasal challenge with S. equi. The horses were vaccinated
for strangles with either a component vaccine (Group C) or a live vaccine (Group L). We
measured changes in strangles serum antibody levels weekly for 20 weeks after vaccinating
horses twice for strangles over a 3-week interval, and for 7 weeks after intranasal
challenge with S. equi in the same horses. Serum antibody responses to the
proline-glutamic acid-proline-lysine (PEPK) antigen with five repetitions (PEPK-5R) were
higher at all times (up to 2.4-fold) following vaccination in Group C than in Group L, and
the value peaked at 2.9-fold above the initial value after the second vaccination in Group
C horses. However, the value was lower than that in horses infected with S. equi, and it
gradually decreased, reaching the initial (week 0) value by the 15th week. Serum antibody
responses to PEPK-5R after challenge with S. equi increased in both groups of horses, but
the value tended to be lower than that reported for unvaccinated horses. In addition, the
average value in Group C was 2.6-fold higher than that of Group L. These results suggest
the serum antibody responses of horses infected with S. equi varies according to the type
of vaccine with which they have been vaccinated. Although the serological diagnostic test
for strangles in which PEPK-5R is used as an antigen is effective for the investigation of
serum antibodies to strangles in vaccinated horses, the present data suggest it is
necessary to consider the vaccination history when interpreting the results. 相似文献
4.
Evasion of phagocytosis is an important virulence determinant of Streptococcus equi (S. equi subsp. equi), the cause of equine strangles and distinguishes it from the closely related but much less virulent S. zooepidemicus (S. equi subsp. zooepidemicus). We describe Se18.9, a novel H factor binding protein secreted by S. equi but not by S. zooepidemicus that reduces deposition of C3 on the bacterial surface and significantly reduces the bactericidal activity of equine neutrophils suspended in normal serum for both S. equi and S. zooepidemicus. Se18.9 is secreted abundantly by actively dividing cells and is also bound to the bacterial surface. Strong serum and mucosal antibody responses are elicited in S. equi infected horses. Although a gene identical to se18.9 was not detected in S. zooepidemicus, sequences encoding proteins of similar size with similar signal peptide sequences were found in 3 of 12 randomly selected strains. Since Se18.9 is unique to S. equi, and immunoreactive with convalescent sera and mucosal IgA, it has potential for immunodiagnosis and for study of mucosal antibody response to S. equi. 相似文献
5.
The reactivity of synthesised peptide sets for the M-like proteins SeM and SzPSe with sera from horses infected with Streptococcus equi or Streptococcus zooepidemicus, or control horses, was investigated by an ELISA. Seventeen horses were infected experimentally with S equi or S zooepidemicus, convalescent sera were obtained from 25 horses and control sera were obtained from 1945 horses. The serum antibody responses of individual horses to the peptide sets were highly variable. Some of the peptide sets for SeM reacted strongly with the sera from the horses infected experimentally with S equi, but also reacted with sera from some of the horses infected experimentally with S zooepidemicus. However, the proline-glutamic acid-proline-lysine (PEPK) repeats peptide set, synthesised from the PEPK repeats areas of SzPSe, reacted most strongly with the sera from the horses infected experimentally with S equi and the horses convalescing from strangles, and reacted only minimally with the sera from the horses infected experimentally with S zooepidemicus and the control horses. 相似文献
6.
The reactivity of the proline-glutamic acid-proline-lysine (PEPK) repetition peptide antigen in 3176 serum samples was investigated to evaluate its utility as an antigen for the serological diagnosis of strangles. The reactivity of the sera of horses infected with Streptococcus equi subspecies equi was high when the peptide had several PEPK repetitions. However, as the number of PEPK repetitions increased, the reactivity of the antigen with the sera of horses infected with Streptococcus equi subspecies zooepidemicus also increased. In horses infected experimentally with S equi, the reactivity of the PEPK antigen with five repetitions increased one week after inoculation and continued to increase during the following four weeks. The optical density (OD) values of test sera from horses infected experimentally with S equi and sera from horses that had recovered from strangles were high. The od values of sera from horses that had recovered from an experimental infection with S zooepidemicus and of sera from healthy horses were comparatively low. 相似文献
7.
The ability of either formalin-treated or heat-inactivated whole Streptococcus equi cell vaccines or partially purified M-protein of S. equi to give rise to protective antibody levels was studied in Standardbred foals by serological means. Two commercial preparations, i.e. a beta-propiolactone killed whole S. equi cell bacterin and a cell-free extract of S. equi cells were included in the study. The mean passive hemagglutination antibody titers (10 X log2) in sera of foals given either four doses of formalin-treated whole cell vaccine or an initial dose of formalin-treated followed by three doses of heat-inactivated vaccine with or without levamisole were significantly higher two weeks after the final dose. These passive hemagglutination antibody titers were higher in foals given formalin-treated whole cell vaccine (6.7 +/- 1.5) than given commercial bacterin (4.5 +/- 2.1). The passive hemagglutination antibody titers in all the groups decreased at 12 to 16 weeks after fourth dose of the vaccine. Foals given a commercial cell-free extract did not show a significant increase in passive hemagglutination antibody titers even up to four weeks after third dose. A group of six pony foals immunized with partially-purified M protein showed mean passive hemagglutination antibody titers lower than those observed in foals given whole cell vaccines. In a challenge experiment with S. equi, two of six foals vaccinated with partially-purified M-protein and all three controls developed clinical disease. The passive hemagglutination antibody of vaccinated foals increased after challenge, while at 28 days postchallenge the passive hemagglutination antibody titers of vaccinates and recovered controls were similar. 相似文献
8.
C R Sweeney C E Benson R H Whitlock D A Meirs S O Barningham S C Whitehead D Cohen 《Journal of the American Veterinary Medical Association》1989,194(9):1281-1286
The age-specific attack rates of Streptococcus equi infections of the upper respiratory tract and lymph nodes (strangles) in horses for the different age groups were 17.6% for broodmares, 47.5% for 1-year-old horses, and 37.5% for foals. Streptococcus equi was isolated from nasal, pharyngeal, or lymph node specimens in 31 (60.8%) of 51 sick horses. A male 1-year-old horse, shipped from Kentucky to farm A, was considered to be the index case. Six (19.4%) of 31 horses with strangles remained as shedders of S equi after clinical signs of the disease had ended. Shedders of S equi were not identified from horses that were exposed to infected horses but never developed strangles. 相似文献
9.
Rhodococcus equi: equine neutrophil chemiluminescent and bactericidal responses to opsonizing antibody 总被引：1，自引：0，他引：1
The opsonic capacity of serum containing R. equi-specific antibody was compared with antibody-deficient sera using luminol-dependent chemilumenscence (LDCL) and bactericidal assays. These assays incorporated peripheral blood polymorphonuclear neutrophilic leukocytes (PMNL) exposed to R. equi opsonized with neonatal equine pre-colostral serum (control) or serum from foals with R. equi infections (principal). All sera were complement inactivated at 56 degrees C for 30 min. Bacteria were obtained from the lung of a foal with R. equi pneumonia. Neutrophils were obtained from one adult horse for LDCL and another for bactericidal assays. Chemiluminescence of PMNL exposed to R. equi opsonized with control or principal sera was measured in a liquid scintillation counter. Mean peak LDCL within 1 h was significantly (P less than 0.01) higher with principal sera (2.4 X 10(5) cpm) than with control sera (0.018 X 10(5) cpm). A radioisotope bactericidal assay was used to determine the effect of control or principal sera on PMNL capacity to kill R. equi. Mean peak percent kill of R. equi by PMNL within 2 h was significantly (P less than 0.01) higher with principal sera (95.2%) than with control sera (54.6%). Enzyme-linked immunosorbent assay (ELISA) values for R. equi-specific antibody were determined on all sera. Mean ELISA values were significantly (P less than 0.01) higher for principal sera (71.8) than for controls (0.0). This investigation documents the presence and biological effectiveness of opsonic activity in complement-inactivated sera from foals with R. equi infections and R. equi-specific antibody. 相似文献
10.
Jacobs AA Goovaerts D Nuijten PJ Theelen RP Hartford OM Foster TJ 《The Veterinary record》2000,147(20):563-567
As part of a search for a safe and efficacious strangles vaccine, several different vaccines and different vaccination routes were tested in foals. The degree of protection was evaluated after an intranasal challenge with virulent Streptococcus equi by clinical, postmortem and bacteriological examinations. Inactivated vaccines containing either native purified M-protein (500 microg per dose) or whole S equi cells (10(10) cells per dose) administered at least twice intramuscularly at intervals of four weeks, did not protect against challenge. Different live attenuated S equi mutants administered at least twice at intervals of four weeks by the intranasal route were either safe but not protective or caused strangles. In contrast, a live attenuated deletion mutant administered intramuscularly, induced complete protection but also induced unacceptable local reactions at the site of vaccination. Submucosal vaccination in the inner side of the upper lip with the live attenuated mutant at > or =10(8) colony-forming units per dose, appeared to be safe and efficacious in foals as young as four months of age. The submucosal vaccinations caused small transient swellings that resolved completely within two weeks, and postmortem no vaccine remnants or other abnormalities were found at the site of vaccination. 相似文献
11.
REASONS FOR PERFORMING STUDY: Streptococcus equi is the cause of strangles in horses. To improve diagnostic sensitivity, development and evaluation of DNA-based methods are necessary. OBJECTIVES: To evaluate diagnostic methods and observe the pattern of bacterial shedding during natural outbreaks. METHODS: Two herds with natural outbreaks of strangles were visited over a period of 15 weeks and 323 samples originating from 35 horses investigated. The diagnostic use of a nested PCR test was evaluated using a collection of 165 isolates of Lancefield group C streptococci (species specificity) and swabs from nasal passages or from abscesses from horses infected with S. equi (diagnostic sensitivity). RESULTS: All 45 S. equi isolates tested positive in the nested PCR, whereas no amplicon was formed when testing the other 120 Lancefield group C isolates. A total of 43 samples were collected from 11 horses showing clinical signs of strangles during the study period. The diagnostic sensitivity for PCR test was 45% and 80% for samples from the nasal passages and abscesses, respectively; the corresponding diagnostic sensitivity for cultivation was 18% and 20%. The diagnostic sensitivity was significantly higher for PCR than for bacterial cultivation. Furthermore, the shedding of S. equi in 2 infected horse populations was evaluated. An intermittent shedding period of S. equi of up to 15 weeks was recorded in this part of the study. It was also shown that shedding of S. equi occurred both from horses with and without clinical signs. CONCLUSIONS AND POTENTIAL RELEVANCE: The nested PCR test represents a species-specific and -sensitive method for diagnosis of S. equi from clinical samples. It may, however, be desirable in future to develop detection methods with high diagnostic sensitivity and specificity without the potential problems inherent in nested PCR. 相似文献
12.
The temperature sensitive and host range mutant clone 147 of equine herpesvirus 1 (EHV-1) was assessed for its ability to protect conventional, susceptible adult horses against respiratory infection by EHV-1 and equine herpesvirus 4 (EHV-4).Intranasal (IN) vaccination with 5.2 log(10) TCID(50) did not cause adverse clinical reactions although a limited virus shedding and viraemia (leukocytes) was observed in 11 of 15 and 10 of 15 vaccinated horses respectively. All 15 vaccinated horses showed a significant seroresponse to both EHV-1 and EHV-4 for virus neutralising (VN) antibody. None of 14 control horses shed virus or became viraemic or seroconverted prior to challenge. EHV-1 challenge (dose 6.0 log(10)) 6 weeks after vaccination resulted in pyrexia in all eight control horses while eight vaccinated horses remained unaffected. Six control horses developed nasal discharge, five of which were mucopurulent nasal discharge (mean duration 3.2 days) which also occurred in four vaccinated horses for 1 day. All eight control horses shed challenge EHV-1 at a significantly higher level (group mean titre 2.6+/-0.4 log(10) TCID(50) per sample) and for much longer (mean duration 4.8+/-1.5 days) than that (group mean titre 1.4+/-0.8 log(10) TCID(50) per sample and mean duration 1.5+/-0.5 days) in six vaccinated horses. Furthermore, all eight control horses became viraemic (mean duration 2.9 days) but viraemia did not occur in eight vaccinated horses. Following EHV-1 challenge, all eight control horses showed a significant VN antibody rise to both EHV-1 and EHV-4 but this occurred in only one vaccinated horse and to EHV-4 only. In EHV-4 challenge (dose of 4.2 log(10) TCID(50)) of a separate pair of seven vaccinated and six control horses, 6 weeks after EHV-1 vaccination resulted in pyrexia (mean duration 2.3 days) and nasal discharge (mean duration 1.8 days) in three and five control horses respectively but the only reaction observed in the vaccinated group was nasal discharge for 1 day in one animal. All six control animals shed virus (mean titre 2.5+/-0.6 log(10) TCID(50) per sample and mean duration 2+/-0.6 days) compared to one vaccinated animal. Although EHV-4 viraemia is rare, 3 of 6 control horses became viraemic after EHV-4 challenge but this was not observed in vaccinated horses. After EHV-4 challenge 3 and 5 of 6 control horses seroconverted for VN antibody to EHV-1 and EHV-4 respectively; a non-responsive control horse had high level of pre-existing VN antibody to EHV-4. However, only 1 of 7 vaccinated horses showed a significant antibody rise and only to EHV-4. 相似文献
13.
Recently there has been increased awareness of the role of the carrier state in propagating Streptococcus equi var equi (S equi) infections (strangles), although the anatomical location of the organisms in chronic carriers has not been consistently established. This case report describes a chronic strangles outbreak in a riding school, that was monitored over six months by repeated clinical and endoscopic guttural pouch examinations. All asymptomatic horses that had positive S equi cultures on nasal swabs or guttural pouch lavages were found to have lesions in their guttural pouches. These lesions included empyema, chondroids and previously undescribed chronic discharging lesions on the floor of the medical compartment of the guttural pouches. These observations further support previous studies indicating the importance of investigating the guttural pouches in horses suspected to be asymptomatic carriers of this organism. 相似文献
14.
Anzai T Sheoran AS Kuwamoto Y Kondo T Wada R Inoue T Timoney JF 《Veterinary immunology and immunopathology》1999,67(3):235-246
Streptococcus equi causes equine strangles. The acute disease has many of the hallmarks of an acute response including high fever, elevated plasma fibrinogen and neutrophilia, affects known to be mediated by proinflammatory cytokines. The objective of this study was to screen-culture supernatants from equine clinical isolates of S. equi and S. zooepidemicus for stimulation of mitogenic responses by horse peripheral blood mononuclear cells. Mitogenicity comparable to that of concanavalin A was detected in culture supernatants of S. equi strains but not in those of S. zooepidemicus. Mitogenicity was neutralised by Proteinase K and a post-strangles convalescent serum, and evidence for the presence of both thermo-resistant and thermo-labile mitogenic factors was obtained. Release of proteinaceous immunogenic mitogens in combination with the antiphagocytic protein SeM unique to S. equi may therefore contribute to some of the severe clinical manifestations of acute strangles in the horse. 相似文献
15.
Effect of vaccination with live or killed Pasteurella haemolytica on resistance to experimental bovine pneumonic pasteurellosis 总被引：13，自引：0，他引：13
A W Confer R J Panciera R W Fulton M J Gentry J A Rummage 《American journal of veterinary research》1985,46(2):342-347
Using 6- to 8-month-old beef calves, 3 experiments were conducted to compare the effect of vaccination with live or killed Pasteurella haemolytica on resistance to a transthoracic challenge exposure with the organism and to correlate serum antibody response with resistance. In each experiment, calves were vaccinated twice at 1-week intervals and were challenge exposed 21 days after the first inoculation. Lung lesions were evaluated by a system, such that higher scores indicated the more severe lesions. In each experiment, calves immunized with live P haemolytica had lower lesion scores than calves vaccinated with saline solution or bacterin. In 2 of the experiments, the differences were significant (P less than 0.05). In all experiments, calves vaccinated parenterally with a commercial P haemolytica/P multocida bacterin or with a formalin-killed P haemolytica bacterin had lesion scores that were not significantly different (P greater than 0.05) than for control calves vaccinated with saline solution. Live and killed bacterial preparations induced a significant serum antibody response to P haemolytica as measured by a quantitative fluorometric immunoassay. The antibody response to vaccination was not affected by preexisting titers to P haemolytica. Serum antibody titers were not consistently as high for calves vaccinated with bacterins as for calves vaccinated with live organisms. Although high antibody titers correlated with low lesion scores when calves vaccinated with saline solution or live organisms were analyzed collectively, there was not a significant correlation between the 2 variables when calves, vaccinated with saline solution or with bacterin, were analyzed collectively. These data indicate that, although bacterins may induce a detectable serum antibody response, they do not induce protection against transthoracic challenge exposure to P haemolytica. 相似文献
16.
LR JORM 《Australian veterinary journal》1990,67(12):436-439
A questionnaire survey of 179 horse studs in New South Wales was conducted to estimate the incidence of strangles during 1985 to 1988, to identify risk factors for strangles outbreaks and to assess the effect of strangles vaccination. Forty-nine of the studs (27.4%) had at least one strangles outbreak during this period and 62 studs (34.6%) had at least one case of strangles. The average incidence of strangles was 2.1 cases per 100 horses per year. The risk of strangles increased progressively with the total horse population and rose markedly when more than 100 mares had been served in the 1988-89 season. Certain types of feeders, fences and water sources were also significantly associated with outbreaks of strangles. Strangles vaccine was used on 63 studs (35.2%). Thirty-seven of these (58.7%) used the manufacturer's recommended vaccination regime. When other risk factors were taken into account, vaccination had no significant effect on the likelihood of a strangles outbreak. 相似文献
17.
A commercial enzyme-linked immunosorbent assay (ELISA) to detect serological response to vaccination and virulent challenge with type 1 (X-73) Pasteurella multocida was used to determine the best vaccination protocol for broiler breeders against fowl cholera. Birds vaccinated twice, at 10 and 19 weeks of age, with the avirulent Clemson University (CU) strain both times, with a commercial bacterin first and the CU strain second, or with the CU strain first and bacterin second had the highest survival rates (98-100%) following challenge at 25 weeks. The two groups that received the CU strain and bacterin also produced the highest mean ELISA antibody titers (greater than 10,000). Birds vaccinated once, at 10 weeks, with the CU strain had the same survival rate as birds vaccinated twice with bacterin (90 and 91%). Under the conditions of this experiment, an ELISA titer greater than or equal to 1000 resulted in at least a 92% survival rate after virulent challenge (23% survival in nonvaccinates). 相似文献
18.
This study examined the protection induced by oil adjuvant vaccine and broth bacterin in mice. Protective immunity was induced by both oil adjuvant and bacterin vaccination procedures. Oil adjuvant vaccination induced a 10(5)-fold increase for lethal challenge over control mice, while secondary vaccination induced a further 10-fold increase in resistance to lethal challenge. Broth bacterin induced a slightly weaker protective response with 10(4)- and 10(5)-fold increases in resistance to lethal challenge following primary and secondary vaccination, respectively. There was a significant relationship between IgG antibody levels and resistance to challenge (P = 0.026). Protection lasted for at least 20 weeks after a primary oil adjuvant vaccination. There was also a strong and significant relationship between IgG antibody levels and the passive protection afforded by serum transfer in each experiment within this study and the overall correlation was highly significant (P = 0.00001). There appeared to be a relationship between protection and the antibody response to major protein bands with the apparent molecular mass Mr. 94,000; 80,000; 67,000; 35,000 and 32,000 as well as to the bands in the region of the lipopolysaccharide components of P. multocida (approximately Mr, 14-15,000). Whether protection resulted from recognition of specific antigens or was a result of both antibody levels and antibody specificity remains to be defined. 相似文献
19.
Both the complement-fixation test (CFT) and the indirect fluorescent antibody test (IFAT) were conducted on weekly serum samples from nine Arab geldings for 28 days before and 256 days after their exposure to Babesia equi of European origin. On an average the IFAT became positive 8 days before the CFT and showed higher relative serum titer increases. Both test procedures successfully detected infection and neither showed an appreciable drop in titer during this time frame, with the exception of the CFT, which showed a transient drop immediately following treatment with imidocarb. A test conducted 540 days after infection showed four of the eight surviving, and presumably infected, horses to be negative on CFT, where as all eight were still positive on IFAT. Comparisons made with the IFAT, on horse sera from B. equi infection of both European and North American origin, utilizing homologous and heterologous antigens, showed significantly higher titers with homologous antigens. 相似文献
20.
H J Chu L G Chavez B M Blumer R W Sebring T L Wasmoen W M Acree 《Journal of the American Veterinary Medical Association》1992,201(3):403-411
The immunogenicity and efficacy of a commercial Borrelia burgdorferi bacterin was evaluated for stimulation of the host immune response and protection against clinical disease associated with experimentally induced borreliosis in dogs. A total of 30 vaccinated and 24 control dogs were used in 3 separate studies. The vaccine was given IM as two 1-ml doses separated by a 3-week interval. Two weeks or 5 months following the last vaccination, the dogs were challenge inoculated with 7 daily doses of a virulent preparation of a B burgdorferi field isolate through intraperitoneal, subcutaneous, and intradermal routes with or without glucocorticoid administration at the same time. The development of B burgdorferi spirochetemia and clinical disease in the dogs after challenge exposure was studied. Serum samples were obtained from the dogs at various times during the study for serum neutralizing antibody determination and protein immunoblot antibody assay against various geographic isolates of B burgdorferi. Challenge exposure induced limb/joint disorder, fever, anorexia, signs of depression, and B burgdorferi spirochetemia in the nonvaccinated control dogs. The vaccine was found to elicit cross-reactive serum neutralizing and protein immunoblot antibody responses in dogs to various isolates of B burgdorferi and to protect the vaccinated dogs against experimentally induced borreliosis. 相似文献