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1.
Schistosomiasis japonica is currently the most serious parasitic disease in mainland China and it is estimated that several million people are infected. Furthermore, it is also responsible for the deaths of many domestic animals. In order to establish an effective diagnostic method, the gene encoding Sjc26GST was cloned and expressed in Escherichia coli as a fusion protein with His-tag. The purified reSjc26GST was used as an antigen for an enzyme-linked immunosorbent assay (ELISA) and for immunoblotting detection of Schistosoma japonicum antibodies in water buffaloes. Our results showed that mean OD values of specific serum IgG antibodies from egg-positive buffaloes were 3.37-fold higher than what was found in egg-negative buffaloes from non-endemic areas. The data also showed the OD value of the endemic egg-negative group reached as high as 1.69 times as that found in non-endemic areas. The positivity rate of egg-positive buffaloes was 100%, but was 30.3% in the endemic egg-negative group. Infected bovine antisera also recognized reSjc26GST, a 27 kDa protein as determined by Western blot. These results suggest that the recombinant GST expressed in E. coli should be an effective diagnostic reagent for detection of antibody against S. japonicum in buffaloes. Due to straightforward production, excellent sensitivity and high specificity, the reSjc26GST described in this study can be considered as a candidate protein for immunological diagnosis of bovine schistosomiasis. Developing reSjc26GST, with its potential diagnostic values, will be useful for diagnosis and surveillance of schistosomiasis in controlling the spread of this parasitic disease in domestic animals.  相似文献   

2.
Resistance to renal leptospirosis was demonstrated in cattle vaccinated with Leptospira interrogans serotype pomona bacterin. Fewer vaccinated cattle given challenge inoculum of virulent serotype pomona leptospires 12 months after vaccination had kidneys with gross focal lesions in the cortex than did nonvaccinated controls. Histopathologic changes characteristically associated with renal leptospirosis occurred less frequently and renal tissue damage was less severe in vaccinated cattle than in nonvaccinated controls. The isolation of serotype pomona from only 1 of 29 vaccinated cattle, compared to 7 isolations from 11 nonvaccinated cattle, at 26 days after challenge inoculum was given, indicated that mild renal infection occurred only infrequently in vaccinated cattle. It appeared that challenge inoculation of vaccinated cattle with virulent serotype pomona leptospires stimulated an accelerated secondary immune response in which immunity limited the multiplication of leptospires in the kidney.  相似文献   

3.
Cattle, vaccinated as calves with Cowdria ruminantium-infected tick stabilate, were challenged 6, 12 and 24 months later. In the absence of tick challenge, vaccination of calves induced a partial immunity against subsequent challenge at 12 and 24 months. In animals exposed to ticks, the resistance was no better than that of control, unvaccinated cattle. When they were challenged at 6 months of age there was no difference between vaccinated and unvaccinated calves, either in the absence or presence of tick challenge, and all the animals manifested a high degree of natural resistance. This study therefore suggests that the value of vaccinating Afrikander-cross calves in heartwater endemic areas should be further investigated. The indirect fluorescent antibody (IFA) test proved to be a valuable means of monitoring the serological response of vaccinated animals and detecting the sero-conversion of animals exposed to tick infection. On one hand, there was good correlation between the febrile reaction and the results of the IFA test on the sera of vaccinated and control cattle challenged with the heartwater agent, in that all sero-positive animals were resistant to challenge. On the other hand, though, a considerable percentage of the animals that were serologically negative were also resistant to challenge.  相似文献   

4.
A trial was conducted in two villages (one containing cattle infected with brucellosis and one not containing infected cattle) in Timor, Indonesia to determine the serological response to vaccination with Brucella abortus strain 19 in Bali cattle (Bos javanicus) (n = 599). Mature female cattle were immunised with low-dose strain 19 (2x10(8)-6x10(8) colony forming units) and calves (6-12 months) with high-dose strain 19 (4x10(10)-12x10(10) colony forming units). Other mature females and calves were inoculated with sterile vaccine diluent and formed a non-vaccinated in-contact control group. The seroprevalence and mean titres were highest in the vaccinated cattle 3 months after vaccination. These then receded, however, 1% of vaccinated calves and 1.9% of vaccinated cows from the village without infected cattle were still seropositive on the complement-fixation test (CFT) 24 months after vaccination. Non-vaccinated seropositive animals were more likely to have aborted or had a stillbirth and were less likely to have produced a calf than were seronegative cows from the village containing infected animals. We concluded that strain 19 vaccine induced protection in Bali cattle and that this vaccine might play an important role in the control of bovine brucellosis in Timor.  相似文献   

5.
In the past decades, vaccination against paratuberculosis in cattle was performed in The Netherlands only on a limited scale. Because of its interference with the diagnosis of bovine tuberculosis, vaccination was restricted to herds with a high prevalence of clinical cases of paratuberculosis and was meant to aid in the economical survival of the farm. Recently, a voluntary paratuberculosis certification program has started, based in part on serological screening of cattle of at least 3 years of age. Herds that have been vaccinated against paratuberculosis are, therefore, likely to encounter problems when entering this program.The aim of this study was to evaluate the immune response resulting from vaccination with a heat-killed paratuberculosis vaccine. Over a period of 12-14 years, new-born calves were vaccinated in two herds. The B-cell response was evaluated using both the complement-fixation test (CFT) and an enzyme-linked immunosorbent assay (ELISA) and the cell-mediated immune response was evaluated using the gamma-interferon assay. Data obtained show a marked and prolonged effect of the vaccination on both cellular and humoral immune responses, in particular to the paratuberculosis antigen but also to the bovine tuberculosis antigen, using the respective tests. These responses were detected rapidly after vaccination. The individual responses were highly variable between animals with respect to both the level and to the duration of the evoked immune response. No relation between the results obtained with the ELISA and the CFT was observed. In conclusion, for a large number of vaccinated cattle, a long lasting interference is to be expected with the presently available immunodiagnostic methods for both bovine tuberculosis and paratuberculosis.  相似文献   

6.
Previous trials of an experimental Taenia ovis vaccine using the recombinant antigen GST--45W(B/X) established that it was possible to achieve >90% protection against a single artificial challenge of T. ovis eggs. This trial was undertaken to assess vaccine efficacy against artificial challenge and natural infection acquired by lambs grazing contaminated pasture. Two hundred Romney lambs were vaccinated at 6 and 12 weeks of age. One hundred control lambs were not vaccinated but were allowed to run with the vaccinated mob. At 15 weeks of age, 10 controls and 18 vaccinated lambs were artificially challenged with 2000 T. ovis eggs. The remaining control and vaccinated lambs were allowed to graze contaminated pasture for 3 weeks and were then moved to clean pasture for 5 months. The artificially challenged lambs plus 24 of the field-infected lambs were slaughtered and the carcasses dissected to obtain cyst counts. The remaining field-infected lambs were slaughtered at a commercial processing plant and the carcasses examined by conventional meat inspection. The results showed that the vaccine provided a high level of protection against artificial challenge (92%) and natural infection (98%) when assessed by carcass dissection. The data from commercial meat inspection showed that vaccination provided 89% efficacy against downgrading or condemnation compared to non-vaccinated control lambs. The average difference in carcass values between vaccinated and non-vaccinated groups was 4.36 dollars, representing a 35% loss in value due to T.ovis infection in non-vaccinated lambs.  相似文献   

7.
The current study was designed to test the immunoprophylactic properties of native (nFh12) and recombinant (rFh15) antigens from Fasciola hepatica in sheep subsequently infected with the fluke. Thirty lambs were divided into six groups according to various patterns of immunisation and times of infection and necropsy. The antigens were emulsified in Freund's adjuvant. Levels of specific anti-nFh12 and anti-rFh15 antibodies rose rapidly by 2 weeks after the first immunisation and were always significantly higher in immunised-infected sheep than in control-infected sheep. On completion of the trial there was no difference in fluke burden between groups vaccinated with either of the antigens and non-immunised controls. However, worm size and faecal egg counts were significantly diminished in the sheep vaccinated with either of the antigens, suggesting an anti-fecundity effect. This is the first report of experimental vaccination of sheep against F. hepatica with purified native and recombinant antigens related to fatty acid binding proteins.  相似文献   

8.
Fasciolosis, caused by trematodes of the genus Fasciola, is one of the most important diseases of farmed ruminants in temperate and tropical zones. The appearance of Fasciola hepatica populations that are resistant to common flukicidal drugs means that new methods of treatment will soon be required. The future prospect for the development of anti-liver fluke vaccines is optimistic and given their consumer acceptability and environmental friendliness, offer the best way forward. Cathepsin L proteases (Fhe CL 1 and Fhe CL 2), secreted by liver flukes at all stages of their development in the mammalian host, are believed to play important roles in facilitating parasite migration (tissue degradation), feeding and immuno-evasion. The authors consider them prime targets for which new vaccines can be developed. Vaccine studies in cattle and sheep have shown that protection levels of up to 72 and 79 per cent, respectively, can be obtained with immunisations of cathepsin Ls in Freunds' adjuvant. The vaccine also exhibited high anti-embryonation/anti-fecundity effects on parasites that survived in vaccinated animals and thus could have a major impact on the transmission of disease to the intermediate host. While natural infections in sheep and cattle appear to elicit non-protective Th2 immune responses, the authors' studies indicate that the protection induced by vaccination involves elements of a Th1 response.  相似文献   

9.
A vaccination trial was conducted to evaluate the potential benefit of Haemonchus contortus gut membrane proteins as vaccine antigens under field conditions in Louisiana. The trial was conducted in the summer of 1996 in a flock of ewes grazing pasture naturally infected with H. contortus. Ewes were randomly assigned to three treatment groups (vaccine, adjuvant only, and saline) and fecal egg counts (FEC, measured as eggs per gram of feces), packed cell volumes (PCV), and antibody levels were monitored fortnightly for 12 weeks. It was shown by FEC that there were large individual variations in susceptibility to H. contortus in both vaccinated and non-vaccinated sheep, a finding which could have masked differences between treatments when analyzed by conventional statistical methods. Based on their egg counts before the period when the vaccination could have had an effect, all ewes were categorized as 'susceptible' or 'relatively resistant'. The significance of differences between FEC, PCV and antibody responses of vaccinated and control sheep were tested separately for the 'susceptible' and 'relatively resistant' category. The 'susceptible' vaccinates shed 65% fewer worm eggs during the period when the vaccine could have had an effect, but the difference was only significant on Week 6 post-vaccination. In these experiments, it was difficult to completely exclude the confounding effect of having 'relatively resistant' sheep in the control group. More studies are needed to further evaluate H11 and H-gal-GP antigens under field conditions.  相似文献   

10.
A vaccination study was conducted in a herd of purebred Hereford cattle representing 4 selection (genetic) lines. For each of 2 years, half of the cattle were vaccinated with a pilus-enriched Moraxella bovis bacterin. Cows were vaccinated before parturition, and calves were vaccinated at 2 to 3 months of age. None of the cattle was vaccinated for 1 year preceding and 1 year after the 2 years in which cattle were vaccinated. There was a significantly (P less than 0.05) lower percentage of infectious bovine keratoconjunctivitis (IBK) in calves during years cattle were vaccinated than during years cattle were not vaccinated. During years cattle were vaccinated, there were lower percentages of IBK in vaccinated calves when compared with the percentages of IBK in nonvaccinated calves. When calves were compared on the basis of selection lines, regardless of the vaccination group, there were consistent differences in the percentages that developed IBK. Although calves with pigmented and nonpigmented eyes (representing all 4 genetic lines) developed IBK, the genetic line of calves with the most pigmented eyes had the lowest (P less than 0.05) percentage of IBK. Also, across all genetic lines, there was less IBK in pigmented eyes than in nonpigmented eyes. Seemingly, vaccination of dams, before parturition, and young calves reduced the occurrence of severe IBK in a herd situation under natural exposure conditions. The resistance or susceptibility in cattle under good management may be influenced by genetic factors.  相似文献   

11.
Young cattle and buffaloes were vaccinated subcutaneously and intradermally with a live vaccine containing Pasteurella multocida serotype B:3,4. Twelve months after vaccination three of five young cattle in the subcutaneously vaccinated group and three of four in the intradermally vaccinated group were protected against serotype B:2 challenge. Eleven buffaloes vaccinated subcutaneously and two vaccinated intradermally survived the same challenge 13 months after vaccination.  相似文献   

12.
Serum antibody titers to canine parvovirus (CPV), canine adenovirus-1 (CAV-1), and canine distemper virus (CDV) were measured in dogs with known immunization status. The dogs represented 3 groups: nonvaccinated dogs less than 12 months old; vaccinated dogs less than 12 months old; and adult dogs greater than 12 months old. For practical reasons, the population from which the specimens were obtained could be considered as free from natural infection with CAV-1 and CDV. In nonvaccinated dogs less than 12 months old, antibodies against all 3 viruses were measured at the time the dogs were given their first vaccination. Altogether, 50.7% of the dogs had titer greater than or equal to 1:10 to CPV, and 26.1 and 46.2% had titer greater than or equal to 1:8 to CAV-1 and CDV, respectively. The concentration of maternal antibody seemed to be of major importance for failure of immunization with use of inactivated CPV vaccine, but not with CAV-1 and CDV vaccination. In dogs less than 12 months old and vaccinated against CPV infection with inactivated virus, only 11.5% had titer greater than or equal to 1:80. In dogs vaccinated against infectious canine hepatitis and canine distemper, 63.2 and 78.3%, respectively, had titer greater than or equal to 1:16. In adult dogs greater than 2 months old and vaccinated against CPV infection, less than 50% had titer greater than or equal to 1:80, regardless of time after vaccination. There was no significant difference in titer between vaccinated and nonvaccinated dogs.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

13.
Twenty-six mixed-breed (14 males, 12 females) dogs were used in a double-blind study to evaluate the effect of milbemycin oxime against naturally acquired infection with Ancylostoma caninum. Dogs were ranked and paired, on the basis of number of hookworm eggs/g of feces, and treatment was randomly assigned. Each dog was given either the study drug or placebo (1 tablet/11.4 kg [0.5 mg/kg] of body weight). Eggs per gram of feces enumeration was done on days 3 and 7 after treatment, and dogs were euthanatized on day 7. On day 3, 5 of the 13 dogs in the milbemycin-treated group had hookworm eggs in the feces (results of the McMaster test). In these dogs, mean number of eggs per gram of feces had decreased markedly (from 5,289 to 452) and, by day 7, was 114. At necropsy, 16 A caninum adults were recovered from 2 of the milbemycin-treated dogs. On day 3, 12 of the 13 dogs in the placebo-treated group had hookworm eggs in the feces. Mean number of eggs per gram of feces in these dogs decreased slightly (from 5,243 to 2,646), but did not decrease further by day 7. A mean number of 54.4 A caninum adults was recovered from 12 of the 13 placebo-treated dogs at necropsy. Milbemycin oxime had 97.8% efficacy against A caninum. Results also indicated that milbemycin oxime may be effective against Trichuris vulpis, but not against Dipylidium caninum.  相似文献   

14.
为建立血吸虫虫卵计数的可准确量化和易于操控的小鼠肝脏取样方法,用日本血吸虫人工感染BALB/c系小鼠42 d后,将肝脏分成左叶、中央叶、右叶,分别进行日本血吸虫虫卵计数。结果显示,感染日本血吸虫42 d的BALB/c小鼠肝脏的平均重量为（2.23±0.26）g。左叶、中央叶、右叶和全肝的每克肝脏含卵数（EPG）分别为49.80×103±26.70×103,59.03×103±29.04×103、36.55×103±17.77×103和47.78×103±23.64×103。各肝叶之间差异有统计学意义（P〈0.05）。可见,血吸虫虫卵在肝脏各叶中的分布是不均匀的,以肝中央叶为最多,肝右叶最少。肝脏EPG与各肝叶中EPG符合线性关系,每对配对成虫对肝脏EGP的贡献从3.67×103到6.5×103个虫卵不等。  相似文献   

15.
It has previously been shown that dogs can be vaccinated against heterologous Babesia canis infection using a vaccine containing soluble parasite antigens (SPA) from in vitro cultures of B. canis and B. rossi that are adjuvanted with saponin. In the present study the onset and duration of immunity of vaccinated dogs were studied. Results showed that 3-26 weeks after initial vaccination, dogs effectively limit the level of SPA in plasma upon challenge infection, which was reflected in limited duration and extent of clinical manifestations. There was no statistically significant effect of vaccination on the parasite load in the circulation, which was determined from blood smears. It was further shown that the level of immunity of primary vaccinated dogs (priming and booster vaccination with a 6-week interval) and that of repeatedly vaccinated dogs (a single additional vaccination 6 months after primary vaccination) is comparable. From this study it is concluded that vaccination with this preparation induces protective immunity against clinical babesiosis from 3 weeks after booster vaccination onwards, and remains effective for a period of at least another 6 months. A single booster vaccination is sufficient to maintain immunity for at least another 6 months.  相似文献   

16.
Field trials were carried out in calves using a live bovine respiratory syncytial (BRS) virus vaccine prepared from the attenuated BRS virus, strain rs-52. Two hundred seventy-five and 353 calves were vaccinated intranasally and intramuscularly, respectively. No undesirable postvaccinal reactions were observed in the vaccinated calves. Of the serum neutralizing (SN) antibody negative calves 89.7% (26/29) and 92.8% (90/97) developed SN antibody 1 month after intranasal and intramuscular vaccination, respectively. Most of the calves having SN antibody titers of 1:1 or 1:2 at the time of vaccination showed a significant increase in SN antibody titer. About 70% and 90% of the calves vaccinated intranasally and intramuscularly, respectively, maintained SN antibody for 6 months after vaccination. In a field trial, a natural BRS virus infection occurred about 5 months after the start of the trial. Ten of the 16 unvaccinated control calves showed respiratory symptoms due to BRS virus infection. On the contrary, all of the 68 vaccinated calves exhibited no symptoms at all, indicating efficacy of the vaccine.  相似文献   

17.
Serum samples and bodyweights were taken at regular intervals for six to seven months from piglets, born to foot-and-mouth disease (FMD) vaccinated or unvaccinated sows, which had been vaccinated at one, two, four or eight weeks old. Young pigs, devoid of maternally derived antibodies (MDA), were capable of responding to FMD vaccination at one week old, with no deleterious effects on their growth rate. However, their immunity to experimental infection at six to seven months old was poor (33.3 per cent). Vaccination of four or eight-week-old piglets, born to unvaccinated sows, protected 87.5 per cent from a similar challenge. In piglets, born to FMD vaccinated sows, the MDA had a suppressive effect on the early vaccination response. This suppression, which was affected by the titre of MDA present in the piglets at the time of vaccination, was complete in one-, two- and four-week-old piglets and partial in eight-week-old piglets. Furthermore, none of these piglets were immune to experimental infection at six to seven months old.  相似文献   

18.
Between January 1999 and December 2000 faecal samples from 16264 cattle at 12 dipping sites in the highveld and nine in the lowveld communal grazing areas of Zimbabwe were examined for gastrointestinal (GI) nematode and cestodes eggs, and coccidia oocysts. Strongyle larvae were identified following culture of pooled faecal samples collected at monthly intervals. The effects of region, age, sex and season on the prevalence of GI nematodes, cestodes and coccidia were determined. Faecal egg and oocyst counts showed an overall prevalence of GI nematodes of 43%, coccidia 19.8% and cestodes 4.8%. A significantly higher prevalence of infection with GI nematodes, cestodes and coccidia was recorded in calves (P < 0.01) than in adults. Pregnant and lactating cows had significantly higher prevalences than bulls, oxen and non-lactating (dry cows) (P < 0.01). The general trend of eggs per gram (epg) of faeces and oocysts per gram (opg) of faeces was associated with the rainfall pattern in the two regions, with high epg and opg being recorded during the wet months. The most prevalent genera of GI nematodes were Cooperia, Haemonchus and Trichostrongylus in that order. Strongyloides papillosus was found exclusively in calves. Haemonchus was significantly more prevalent during the wet season than the dry season (P < 0.01). In contrast, Trichostrongylus was present in significantly (P < 0.01) higher numbers during the dry months than the wet months, while Cooperia and Oesophagostomum revealed no significant differences between the wet and dry season. These findings are discussed with reference to their relevance for strategic control of GI parasites in cattle in communal grazing areas of Zimbabwe.  相似文献   

19.
Counts of Fasciola spp. eggs in faeces and measurements of antibody concentration to the excretory/secretory antigens of Fasciola spp. by ELISA were related to the numbers of flukes in the livers of 92 cattle killed in the abattoirs of Hanoi City, Vietnam. In this population, about 22% of the cattle had no flukes, another 22% had between 1 and 10 flukes, 44% between 11 and 100 flukes and 12% had more than 100 flukes in their livers. Of the 14 animals less than 2 years of age, only three were infected. At 2 years of age the mean number of flukes per liver was 10 whereas at 3 years and older, the mean varied between 60 and 80 flukes. Prevalence of infection was 78.3%. No eggs of Fasciola spp. were detected in the faeces of one third of infected cattle and 60% of the counts were less than 100 eggs per gram. The sensitivity of the egg counting method was 66.7% and specificity 100%, overall accuracy was 73.9%. Corresponding values for the ELISA method were 86.1, 70 and 82.6%, respectively. The positive and negative predictive values for the egg counting method were 100 and 45.5% and for the ELISA method were 91.2 and 58.3%, respectively.  相似文献   

20.
Cattle vaccinated with a conventional monovalent type O1 foot-and-mouth disease (FMD) vaccine were challenged between four and 21 days after vaccination by short-term exposure to homologous airborne virus produced by pigs. Transmission was then assessed by housing susceptible cattle with the vaccinated animals and testing and observing all the animals for signs of infection and clinical disease. All 18 cattle vaccinated three weeks before challenge resisted clinical disease and although four contracted subclinical infection, there was no transmission to susceptible cattle in contact. One of the two groups of cattle vaccinated two weeks previously transmitted subclinical infection, but not disease, to susceptible animals housed with them from day 0 after challenge. Subclinical infection was manifested by a transient viraemia which was not followed by a detectable circulating antibody response. Shorter periods (seven or four days) from vaccination to challenge resulted in transmission of disease from clinically normal vaccinated to in-contact animals in one of two experiments. The severe challenge presented by the diseased in-contact animals than overwhelmed the immunity of the vaccinated animals. The results indicate that during emergency vaccination programmes it is advisable to vaccinate all FMD-susceptible animals within the vaccination zone and that at the outer boundary of the zone vaccinated animals should be kept separated from unvaccinated animals for at least three weeks.  相似文献   

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