五种市售鸡传染性鼻炎灭活疫苗免疫效力比较

本研究对国内市场上几个主要鸡传染性鼻炎灭活疫苗生产厂家生产的灭活疫苗免疫鸡只进行血清HI抗体水平测定和攻毒,比较不同公司所产疫苗效力的效力差异,并评估A、C型二价灭活疫苗两次免疫鸡群对国内B型分离株:DL-1株和最近从免疫失败鸡场分离到的SD-1株的交叉保护作用,分析免疫失败的原因.结果表明:A、D、E公司的疫苗免疫两次后,A型HI抗体阳性率分别为92.5%、100%和95%,滴度分别为33.9、55.1和59.9,攻毒保护率都是100%.C型HI抗体阳性率分别为72.5%、38.5%和77.5%,滴度分别为11.4、2.7和27,攻毒保护率分别为80%、70%和80%.而B和C公司的疫苗免疫两次后A型HI抗体阳性率分别为59.4%、77.1%,抗体滴度分别为5.4和21.8,攻毒保护率分别为50%和66.7%;C型HI抗体阳性率分别为54.1%和51.4%,抗体滴度分别为6.1和6.8,攻毒保护率分别为38.3%和50%.在五个疫苗产品中,以A、D、E的保护效力较好,B、C产品效力较差.另外,A、C型二价灭活疫苗免疫后不能对B型菌的攻击提供保护,其A、C型HI抗体阳性率、抗体滴度与对B型菌攻毒保护率无相关性.     

Comparison of antibody responses after vaccination with two inactivated rabies vaccines

Thirty laboratory dogs were randomly assigned to two groups (A and B) of 15 dogs and subcutaneously vaccinated with a single dose of one of two commercially available monovalent inactivated rabies vaccines: RABISIN (Merial, France) (group A) and NOBIVAC Rabies (Intervet International) (group B). Rabies antibodies were measured over a period of 4 months using the fluorescent antibody virus neutralization (FAVN) test. The two vaccines performed differently in terms of magnitude and persistence of rabies antibodies titers in dogs. Two weeks after vaccination, average rabies antibody titers peaked at 2.53 IU/mL (range, 0.17-13.77 IU/mL) and 1.26 IU/mL (range, 0.50-4.56 IU/mL) in groups A and B dogs, respectively. The average FAVN antibody titres against rabies on D28, D56, D84, D112 and D120 were significantly higher in group A than in group B. Although all dogs from group B serologically responded to vaccination, the proportion of dogs with antibody titres >or=0.5 IU/mL dropped significantly after D28 and was statistically significantly lower on D56, D84 and D112 compared to group A dogs. In conclusion, in the context of international trade, the choice of the vaccine and the timing of blood tests are critical factors in achieving successful serological test results after rabies vaccination. RABISIN induces high and sustained antibody titres against rabies, increasing the flexibility for the time of blood sampling after primo-vaccination.     

Experimental aspergillosis in rabbits

Controls, as well as cortisone-treated rabbits, were challenged with Aspergillus fumigatus spores intratracheally. Animals were sacrificed 3, 7, 14 and 28 days after inoculation and their organs cultured and studied histologically. Lesions were produced in both groups, although the cortisone-treated group showed greater pathology and the lesions persisted for a longer period of time than the control groups. Histologically, the pulmonary lesions showed granulomatous pulmonary aspergillosis and suppurative necrotizing pneumonic infiltrates.     

Preweaning mortality in specific pathogen free kittens

The incidence, causes and age distribution of preweaning deaths in a specific pathogen free (SPF) cat colony are described. The age distribution of kitten mortality is compared with that in one other SPF and four conventionally housed colonies. Almost all preweaning deaths in the SPF colonies occurred within the first week of life. The only infectious agent considered to be a cause of death was Escherichia coli. It is suggested that in the selection of breeding stock the mothering ability of the dam is of particular importance.     

The effectiveness of inactivated vaccines applied parenterally to sows to control Escherichia coli diarrhea in piglets in an industrial fattening farm

Different vaccines against Escherichia coli diarrhea of piglets were applied parenterally in pregnant sows at an industrial fattening farm. The following vaccines were used: vaccine No. 1 with non-complete Freund's adjuvant. Tween 80 and Arlacel A, comprising O149:K91,K88; O139:K82; O8:K87,K88; O141:K85,K88; and O64:K? E. coli serotypes; vaccine No. 2 with paraffin oil instead of Freund's adjuvant, comprising the same E. coli serotypes as the vaccine No. 1; stable specific vaccine with 10% aluminium hydroxide, based on E. coli serotypes most frequently isolated from piglets which died at the farm (O149:K91,K88; O8:K87,K88; O20:K17; O64:K?); Gletvax K88 (Wellcome) and NOBI-VAC LT-K88 (Intervet International). The number of piglets which died up to the moment of weaning in comparison to the number of born ones was considered as an indicator of acquired protection. It was found that the most effective in conferring protection against E. coli diarrhea were: vaccine No. 1 and NOBI-VAC. The differences in the mortality rate between piglets originating from sows vaccinated with these vaccines and those from unvaccinated ones were statistically significant (P < 0.05). No significant differences were noted between controls and animals vaccinated with the remaining vaccines.     

Antibody responses of guinea-pigs, rabbits and pigs to inactivated porcine parvovirus vaccines

Antibody responses were compared in guinea-pigs, rabbits and pigs following vaccination with inactivated porcine parvovirus (PPV) vaccines. Mean PPV hemagglutination inhibition (HI) antibody titers of 52, 56 and 36 at 1 week after first vaccination and 896, 640 and 512 at 2 weeks after second vaccination were detected in guinea-pigs, rabbits and pigs, respectively. PPV vaccines prepared with greater concentrations of virus, as determined by hemagglutination (HA) units, and of aluminum hydroxide gel adjuvant, induced higher HI antibody titers in guinea-pigs. Optimal concentrations for inducing consistently high antibody titers consisted of vaccine virus with a HA titer of 256/0.1 ml and gel adjuvant at a final concentration of 50%. A second vaccination at 4 weeks compared to 2 or 3 weeks after first vaccination resulted in higher mean HI titers. These data provide preliminary information on the use of guinea-pigs or rabbits as laboratory animal models for testing the potency of PPV vaccines.     

Sedative and cardiorespiratory effects of intranasal atomized alfaxalone in Japanese White rabbits

ObjectiveTo investigate the sedative and cardiorespiratory effects of intranasal atomization (INA) of alfaxalone using a mucosal atomization device in Japanese White rabbits.Study designRandomized, prospective, crossover study.AnimalsA total of eight healthy female rabbits, weighing 3.6–4.3 kg and aged 12–24 months.MethodsEach rabbit was randomly assigned to four INA treatments administered 7 days apart: Control treatment, 0.15 mL 0.9% saline in both nostrils; treatment INA0.3, 0.15 mL 4% alfaxalone in both nostrils; treatment INA0.6, 0.3 mL 4% alfaxalone in both nostrils; treatment INA0.9, 0.3 mL 4% alfaxalone in left, then right, then left nostril. Sedation was scored 0–13 using a composite measure scoring system for rabbits. Simultaneously, pulse rate (PR), respiratory rate (f_R), noninvasive mean arterial pressure (MAP), peripheral hemoglobin oxygen saturation (SpO₂) and arterial blood gases were measured until 120 minutes. The rabbits breathed room air during the experiment and were administered flow-by oxygen when hypoxemia (SpO₂ <90% or PaO₂ <60 mmHg; 8.0 kPa) developed. Data were analyzed using the Fisher's exact test and the Friedman test (p < 0.05).ResultsNo rabbit was sedated in treatments Control and INA0.3. All rabbits in treatment INA0.9 developed loss of righting reflex for 15 (10–20) minutes [median (25th–75th percentile)]. Sedation score significantly increased from 5 to 30 minutes in treatments INA0.6 and INA0.9 with maximum scores of 2 (1–4) and 9 (9–9), respectively. f_R decreased in an alfaxalone dose-dependent manner and one rabbit developed hypoxemia in treatment INA0.9. No significant changes were observed in PR and MAP.Conclusions and clinical relevanceINA alfaxalone resulted in dose-dependent sedation and respiratory depression in Japanese White rabbits to values considered not clinically relevant. Further investigation of INA alfaxalone in combination with other drugs is warranted.     

Protective effects of vaccines against experimental salmonellosis in racing pigeons

Five inactivated and one attenuated vaccine produced for the prevention of salmonellosis in pigeons were compared in an experimental challenge model. The birds were vaccinated according to the recommendations of the manufacturers and they were infected by gavage with a Salmonella typhimurium (var copenhagen) pigeon strain. The challenged control animals showed severe weight loss, excessive water intake over a prolonged period, and excreted large numbers of salmonellae. None of the vaccines fully protected the pigeons, and only an inactivated oil adjuvant vaccine was able to reduce the severity of the clinical signs significantly. Mortality was low and tended to increase with the severity of the clinical signs. These results do not justify the preventive use of salmonella vaccination in pigeons. Nevertheless, the oil adjuvant vaccine may help in the effective cleaning of lofts after an outbreak of salmonellosis.     

荧光定量RT-PCR方法与兔体定型热试验对于检测猪瘟兔化弱毒疫苗的平行关系

为探讨荧光定量RT-PCR技术与传统兔体定型热试验对于检测猪瘟兔化弱毒疫苗的平行关系,本研究采用荧光定量RT-PCR方法与兔体定型热试验对5份猪瘟兔化弱毒细胞苗成品和6份半成品样品进行平行检测.结果表明,两种检测方法存在正相关性,最低105个病毒拷贝可以使家兔产生定型热反应,最低103个病毒拷贝可以使家兔产生轻热反应.荧光定量RT-PCR检测方法的检测过程仅需3.5h,大大缩短了猪瘟疫苗的检测时间,该方法可以补充传统的兔体定型热反应用于猪瘟兔化弱毒疫苗半成品与成品的检验.     

Protective efficacy of commercial inactivated Newcastle disease virus vaccines in chickens against a recent Korean epizootic strain

Despite the intensive vaccination policy that has been put in place to control Newcastle disease virus (NDV), the recent emergence of NDV genotype VII strains in Korea has led to significant economic losses in the poultry industry. We assessed the ability of inactivated, oil-emulsion vaccines derived from La Sota or Ulster 2C NDV strains to protect chickens from challenge with Kr-005/00, which is a recently isolated Korean epizootic genotype VII strain. Six-week-old SPF chickens were vaccinated once and challenged three weeks later via the eye drop/intranasal route. All vaccinated birds were fully protected from disease, regardless of the vaccine strains used. All vaccinated and challenged groups showed significant sero-conversion 14 days after challenge. However, some vaccinated birds, despite being protected from disease, shed the challenge virus from their oro-pharynx and cloaca, albeit at significantly lower titers than the unvaccinated challenged control birds. The virological, serological, and epidemiological significance of our observations with regard to NDV disease eradication is discussed.     

DNA vaccines and their applications in veterinary practice: current perspectives

Inoculation of plasmid DNA, encoding an immunogenic protein gene of an infectious agent, stands out as a novel approach for developing new generation vaccines for prevention of infectious diseases of animals. The potential of DNA vaccines to act in presence of maternal antibodies, its stability and cost effectiveness and the non-requirement of cold chain have heightened the prospects. Even though great strides have been made in nucleic acid vaccination, still there are many areas that need further research for its wholesome practical implementation. Major areas of concern are vaccine delivery, designing of suitable vectors and cytotoxic T cell responses. Also, the induction of immune responses by DNA vaccines is inconclusive due to the lack of knowledge regarding the concentration of the protein expressed in vivo. Alternative delivery systems having higher transfection efficiency and the use of cytokines, as immunomodulators, needs to be further explored. Recently, efforts are being made to modulate and prolong the active life of dendritic cells, in order to make antigen presentation a more efficacious one. For combating diseases like acquired immunodeficiency syndrome (AIDS), influenza, malaria and tuberculosis in humans; and foot and mouth disease, Aujesky’s disease, swine fever, rabies, canine distemper and brucellosis in animals, DNA vaccine clinical trials are underway. This review highlights the salient features of DNA vaccines, and measures to enhance their efficacy so as to devise an effective and novel vaccination strategy against animal diseases.     

Spontaneous cataracts in laboratory rabbits

Objective To document the occurrence and incidence of spontaneously occurring cataracts in older New Zealand White (NZW) and New Zealand White × New Zealand Red (NZW × NZR – F1) rabbits during prescreening examinations at Alcon Laboratories. Procedures A retrospective study was conducted on prescreening examination records of NZW and NZW × NZR (F1) rabbits at Alcon Laboratories between April 1999 and May 2001. Results A total of 946 rabbits (670 NZW and 276 NZW × NZR) ranging in age from 77 to 288 days were examined. Of the NZW rabbits, 333 were males and 337 were females. Of the NZW × NZR (F1) rabbits, 139 were males and 137 were females. Thirty‐eight NZW rabbits (23 males and 15 females) exhibited immature cataracts in one or both eyes, and three NZW × NZR (F1) rabbits (one male and two females) exhibited cataracts in one or both eyes. The overall incidence of cataracts was 4.3% of all rabbits. Males and females were equally affected, but a significant difference in the incidence of cataracts existed between the NZW and NZW × NZR (F1) rabbits with 5.7% of the NZW rabbits affected and 1.1% of the NZW × NZR (F1) rabbits affected. Conclusion Spontaneous juvenile cataracts occur in rabbits and may develop as incidental lesions during toxicologic studies. The incidence of cataracts noted in our studies is consistent with an autosomal recessive mode of inheritance, but further studies are needed to confirm the mode or modes of inheritance. Hybrid pigmented rabbits (F1 or NZW × NZR) exhibited a significantly lower incidence of cataracts.     

Transmission of pathogenic respiratory bacteria to specific pathogen free pigs at slaughter

The purpose of this study was to evaluate the transmission of pathogenic respiratory bacteria to thirteen 5-month-old specific pathogen free (SPF) pigs, during the slaughtering process in a commercial slaughterhouse. Before transportation, the SPF pigs and the lorry were checked to confirm the absence of pathogenic respiratory bacteria.

Nine SPF pigs (group 1) were in contact in a conventional slaughterhouse with finishing pigs, during 4 h before slaughtering. Four SPF pigs (group 2) were slaughtered immediately at arrival in the slaughterhouse.

Five bacterial pathogens (Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Pasteurella multocida, Haemophilus parasuis and Streptococcus suis) were detected by PCR, after slaughtering, from nasal cavities, tonsils and trachea in the two groups of pigs. Lung samples were PCR negative. Three and four bacterial species were isolated from the pigs of group 2 and group 1, respectively. Cultures were negative from the lungs.

All the bacterial species present in the SPF pigs were detected by PCR. P. multocida was isolated, from three samples of scalding water before the onset of slaughtering.

Our results suggest that the SPF pigs became contaminated mainly by the slaughterhouse environment and the scalding water. Histological examinations revealed that during scalding, contaminated water could reach the trachea and the lungs of pigs. Checks conducted at slaughter for respiratory disorders have to be carried on, but nasal cavities and tonsils are not appropriate for bacteriological investigations. Moreover, bacteriological results obtained from the lungs of slaughtered pigs have to be used with carefulness.     

Cardiovascular effects of increasing dosages of norepinephrine in healthy isoflurane-anesthetized New Zealand White rabbits

ObjectiveTo characterize the cardiovascular effects of increasing dosages of norepinephrine (NE) in healthy isoflurane-anesthetized rabbits.Study designProspective experimental study.AnimalsA total of nine female ovariohysterectomized New Zealand White rabbits weighing 3.4 ± 0.2 kg (mean ± standard deviation).MethodsRabbits were premedicated intramuscularly with buprenorphine (0.05 mg kg^–1) and midazolam (0.5 mg kg^–1). Anesthesia was induced with intravenous propofol and maintained with a 1.1 × minimum alveolar concentration of isoflurane for this species to induce hypotension. Rabbits were administered NE infusions at three doses: low, 0.1 μg kg^–1 minute^–1; medium, 0.5 μg kg^–1 minute^–1; and high doses, 1 μg kg^–1 minute^–1 for 10 minutes each in that order. Cardiovascular variables including heart rate (HR), cardiac output (CO) by lithium dilution technique and systolic (SAP), mean (MAP) and diastolic (DAP) invasive arterial blood pressures measured in the auricular artery were recorded at baseline, 10 minutes after the start of the infusion of each NE treatment and 10 minutes after NE was discontinued. A linear mixed model and a type III anova with Tukey’s post hoc comparison was performed (p < 0.05).ResultsSignificant increases in SAP (28% and 90%), MAP (27% and 90%) and DAP (33% and 97%) were measured with medium and high dose treatments, respectively (p < 0.001), with no changes in CO. HR decreased and stroke volume increased significantly with high dose treatment (by 17% and 15%, respectively; p < 0.05). No arrhythmias were noticed with NE treatments.Conclusions and clinical relevanceThe infusion of NE at 0.5–1.0 μg kg^–1 minute^–1 is a potentially effective treatment for hypotension in healthy isoflurane-anesthetized New Zealand White rabbits.     

The experimental infection of specific pathogen free lambs with Mycoplasma ovipneumoniae.

Six colostrum-deprived SPF lambs inoculated endobronchially with a second passage broth culture of a Scottish strain of Mycoplasma ovipneumoniae, were killed in batches of two at seven, 14 and 28 days post-inoculation. One lamb from each batch showed macroscopic and microscopic lung lesions similar to but milder than those described for respiratory mycoplasmoses in other species of animals and exhibited minor clinical symptoms. Mycoplasma were recovered from all infected but from no control animals: five infected lambs yielded mycoplasma from lung tissue. Two lambs infected with M ovipneumoniae by endobronchial intubation were placed in contact with six other SPF lambs. M ovipneumoniae was recovered from the upper respiratory tract only of all six contact lambs, but no pathological changes were noted in their lungs. Both donor lambs yielded mycoplasma from lung tissue, but microscopic lesions were detected in only one of them, and these were minimal. No seroconversion due to the infection could be demonstrated in any of the lambs by either the indirect haemagglutination or metabolic inhibition tests.     

Immune responses of specific pathogen free foals to EHV-1 infection.

Four foals were raised under specific pathogen free (SPF) conditions. At 3 to 4 months of age, SPF foals and 1 other non-SPF foal were intranasally inoculated with equine herpes virus type 1 (EHV-1). Clinical signs included depression, fever, inappetence and intermittent coughing. Clinical recovery was complete by seven days but high titres of virus were detected in nasal mucus for at least 10 days after inoculation. Clinical illness was less severe in the non-SPF foal. Interferon was detected in the nasal mucus of all foals from 2 days post infection (dpi), persisting until 8 or 10 dpi. ELISA antibody was detected in serum from 6 dpi. Titres continued to rise throughout the period of observation, and were slightly stimulated by re-inoculation. EHV antibody, identified as belonging to the IgM class by the double sandwich ELISA, was detected from 6 dpi. Peak IgM titres were observed between day 10 and 18, declining to base levels by day 42. Virus neutralizing antibody was detectable in serum from day 14 and rises in titre were parallel to that of total ELISA antibody. Cellular immunity in EHV-1 infected SPF horses was examined by the antibody dependent cytotoxicity (ADCC) test and the specific lymphocyte transformation test. The ability of foal neutrophils to effect ADCC decreased significantly between 3 to 10 days after inoculation. Peripheral blood mononuclear cells (PBMC) displayed reactivity towards EHV-1 antigens from about day 14, with maximum stimulation indices being obtained between 28 and 42 dpi.     

两种伊维菌素注射液在家兔体内的生物等效性研究

为评价两种伊维菌素注射液在家兔体内的生物等效性,采用双周期交叉给药方式,将16只健康家兔随机分成2组,按5 mg/kg体重皮下单剂量注射两种伊维菌素注射液,使用HPLC法测定血浆中的伊维菌素,利用3P97药动软件计算主要药动学参数。结果显示,受试制剂和参比制剂的T_(max)分别为(26.45±8.62)h,(22.33±11.72)h;Cmax分别为(182.73±59.27)ng/m L,(166.77±65.25)ng/m L;AUC_(0-t)分别为(21122±9999)ng·h·L~(-1),(19475±7009)ng·h·L~(-1);AUC_(0-∞)分别为(27390±12197)ng·h·L~(-1),(31559±13412)ng·h·L~(-1)。伊维菌素注射液受试制剂与参比制剂的AUC0-t、AUC0-∞、Cmax、Tmax均无显著性差异(P0.05),双单侧t检验结果显示两种制剂生物等效,可为兽医临床给药方案的制定以及合理用药提供参考。