“猪瘟和非洲猪瘟的综合防治措施”专栏(三) 影响猪瘟流行地区疫苗成功接种的关键因素

猪瘟(Classical Swine Fever,CFS)又称猪霍乱,由猪瘟病毒(CSFV)引起,是能给全球养猪业造成严重经济损失的最重要的病毒性疾病之一.在过去的5年中,多项用于测定猪细胞免疫(Cell-Mediated Immunity,CMI)的技术与其他常规技术一起,被用来研究可影响猪瘟病毒特异性免疫诱导的因素.从一系列试验获得的资料证明,细胞免疫应答可提供抗猪瘟感染的保护性免疫.尽管业已证实商用改良型猪瘟活疫苗能够诱导免疫猪产生完全的保护,但包括母源免疫、首次免疫年龄、免疫接种方案和其他病原体引起的并发症等多种因素,均会严重影响猪瘟疫苗在田闻的免疫效果.     

仔猪接种猪瘟疫苗违规操作暴发猪瘟

1 发病情况 我市某镇2个村共8户8窝共100只仔猪发病,8户的仔猪都是在2003年3月20日前后出生,在4月23日接受该镇兽医防检员注射猪瘟疫苗,几天后连续出现发病,主要表现为食欲不振或废绝,个别出现抽搐,死前一两天有强烈腹泻症状,病死猪部分腹下、胸关、四肢内侧等部位有大小不等的出血斑点。虽经过兽医的治疗,但到5月19日止,共死亡75只。2 临床症状 2003年5月19日,我站技术人员接到报告后,当天赶赴现场检查,     

猪瘟疫苗不同接种剂量免疫抗体水平监测试验报告

猪瘟是由猪瘟病毒感染猪而引起的一种急热性、高度传染性疫病,以其流行广泛、传染性强、病死率高而长期威胁着养猪业的1健康发展。近几年我市春秋两季免疫抗体集中监测中,猪瘟抗体合格率均低于口蹄疫、禽流感、新城疫,并且养殖户在使用猪瘟活疫苗时,免疫接种剂量随意性很大,有的严格按照疫苗说明接种1头份,有的盲目加大剂量,接种4-8头份不等。为了探索猪瘟免疫不同接种剂量的抗体效价水平,制定合理的免疫程序提供数据支持,指导养殖户对猪瘟进行科学免疫,开展了本次试验研究。     

口服PHA复合物对仔猪猪瘟疫苗免疫效果的影响

选择体重相近的35日龄断奶仔猪24头,随机分成试验和对照两组,每组12头。35日龄首免,60日龄二免,每头仔猪均肌肉注射猪瘟活疫苗,试验组仔猪免疫后连续7d口服PHA(0.8mg/kg),对照组口服生理盐水。结果显示,在免疫接种前试验组与对照组抗体滴度基本相同,无免疫保护作用。首免10d后,试验组阳转率比对照组显著提高16.7个百分点(P<0.05);二免10d后,试验组阳转率比对照组提高8.4个百分点,没有达到显著水平(P>0.05),但试验组抗体滴度≥64的比率比对照组高41.6个百分点,处于较高的抗体水平。表明PHA复合物与猪瘟活疫苗联合用于仔猪猪瘟疫苗免疫接种,其免疫效果比单用猪瘟活疫苗的效果好,显示PHA能作为一种免疫增强剂,提高仔猪猪瘟疫苗的免疫效果。     

猪瘟乳前免疫的接种方法

乳前免疫是仔猪在哺乳前免疫接种猪瘟疫苗的一种免疫方法。据笔者了解，部分养猪户由于未能准确掌握免疫时间，经常导致免疫失败而引起部分仔猪发生猪瘟而死亡。为确保免疫效果，应注意以下事项。     

猪瘟组织灭活疫苗与猪瘟弱毒冻干活疫苗在免疫效力的比较研究

猪瘟是猪的一种重要的传染性疾病，是由猪瘟病毒引起的一种高度接触性猪传染性疾病。猪瘟病毒属于黄病毒科，瘟病毒属，其基因为RNA。其主要致病机理是致小血管壁的变性，从而导致内脏器官多发性出血梗塞和坏死，以出血和发热为主，呈急性或慢性经过，每年给养猪业造成巨大的经济损失。从50年代初，周泰冲等研制出了猪瘟病毒兔化弱毒疫苗株C株，在我国猪瘟得到了很好的控制。但是近年来随着养殖规模的不断扩大，猪瘟的流行已发生了明显的变化，典型猪瘟已不多见，非典型猪瘟(或温和型猪瘟)普遍流行。     

甘肃地区猪瘟免疫抗体水平调查

为了掌握甘肃省近两年猪瘟免疫情况,我们通过在全省14市州,在春秋两个季度,选择部分养殖场及散养户,用正向间接血凝实验检测猪瘟抗体水平:2012年春秋两个季度猪瘟抗体水平均达到85%以上,2013年全年抗体水平达80.9%,较之2012年有所下降。     

Factors critical for successful vaccination against classical swine fever in endemic areas

Classical swine fever (CSF) or hog cholera, caused by the classical swine fever virus (CSFV), is one of the most important viral diseases that cause serious economic loss to the swine industry worldwide. During the past 5 years, several techniques for measuring porcine cell-mediated immunity (CMI) were applied, in conjunction with other conventional techniques, to study factors that influence the induction of CSFV-specific immunity. Information, obtained from a series of experiments, demonstrated cell-mediated immune responses in providing protective immunity against CSF infection. Although it has been confirmed that commercially available modified live CSF vaccines are able to induce complete protection in vaccinated pigs, several factors including maternal immunity, the age of primary vaccination, vaccination protocol and complications caused by other pathogens, can greatly affect the effectiveness of CSF vaccines in the field.     

Simultaneous vaccination of piglets against foot-and-mouth disease and classical swine fever

Six-week-old piglets, born of unvaccinated sows, were vaccinated against foot-and-mouth disease (FMD) with a trivalent, inactivated vaccine containing an adjuvant or vaccinated against classical swine fever (CSF) with a live attenuated vaccine or against both diseases simultaneously at two different sites. The antibody response to the FMD vaccine was not significantly influenced by the simultaneous vaccination against CSF. FMD vaccine administered simultaneously with the CSF vaccine produced a significantly higher antibody response to CSF than occurred with CSF vaccination only.     

The effect of Trypanosoma evansi infection on pig performance and vaccination against classical swine fever

Although Trypanosoma evansi is not considered as an important pathogen in pigs, it may interfere with other pathogens or vaccinations by its immunosuppressive nature. In order to determine whether T. evansi alters pig performance and induces immunosuppression in pigs, induction of immune responses by vaccination against classical swine fever (CSF) and by immunization with a control antigen, human serum albumin (HSA), was assessed in T. evansi-infected and non-infected animals. Although T. evansi infection did not have a significant influence on growth performance, feed conversion or PCV, antibody responses against both the test antigen HSA and the CSF vaccine were significantly reduced in T. evansi-infected animals as compared to uninfected animals. Moreover, the reduced response against the CSF vaccine appears to be accompanied by a less well-developed protection against CSF with higher fever responses and leukopenia. This immunosuppression might explain the accounts of poor protection of CSF-vaccinated pigs reported in T. evansi-endemic areas of Vietnam, and suggests that prior treatments with trypanocidal drugs to improve the efficacy of CSF vaccination, may be justified.     

三个厂家猪瘟活疫苗免疫效果比较试验

在同一条件下对3个厂家生产的猪瘟细胞源活疫苗进行了免疫效果评价试验,并与猪瘟传代细胞苗免疫效果进行比较。结果发现3个厂家生产的猪瘟细胞源活疫苗存在一定差异,2个厂家的免疫效果较好,1个厂家的免疫效果较差。猪瘟传代细胞苗免疫效果优于猪瘟细胞源活疫苗,猪瘟传代细胞苗免疫1次,抗体合格率高,持续时间长,猪瘟细胞源活疫苗要免疫两次才能获得比较好的效果。同时,我们发现高致病性猪蓝耳病活疫苗（JXA1-R株）对猪瘟抗体产生有一定影响。     

Development of maternal antibodies after oral vaccination of young female wild boar against classical swine fever

An experimental study was performed to investigate the development of maternal antibodies after oral immunisation of young female wild boar against classical swine fever (CSF) using C-strain vaccine. Our results demonstrated that maternal antibodies do not persist in the offspring for more than 3 months. Based on the neutralising serum antibody titres, we assume that piglets of wild sows vaccinated orally twice or immunised once a long time before conception have protective antibodies for approximately 2 months. Furthermore, it seems that the level and the duration of maternal antibodies in the offspring are depend on the age of the female animals at the moment of vaccination as demonstrated in our experiment. The recent vaccination procedure consists of three double vaccinations in spring, summer and autumn. Especially vaccinations in summer and autumn could be crucial for transfer of high maternal antibody titres to the offspring.     

猪瘟重组疫苗的研究进展

猪瘟是严重危害养猪业一种重要传染病,弱毒疫苗的应用一定程度地控制了该病的流行与发生,但仍存在一些缺陷,新型、高效、标记疫苗的研制一直以来成为猪瘟疫苗领域的研究热点。本文对猪瘟重组疫苗领域取得的研究研究进展进行了综述。     

Evaluation of vaccine-induced maternal immunity against classical swine fever

The vaccine-induced maternal immunity against classical swine fever (CSF) was investigated in this study. Eight sows were vaccinated with the Chinese strain of classical swine fever virus (CSFV). The length of time between vaccination and farrowing was 167-217 days. Milk samples from the front, middle and back udder sections and blood samples were taken from the sows on days 3 and 14 after farrowing. Blood samples were obtained from the piglets at the age of 3, 6 and 10 weeks. The antibody level of the milk was examined by ELISA, and that of blood samples by the virus neutralization (VN) test as well. In all 3-week-old piglets and in 80% of the 6-week-old animals the neutralizing antibody level reached the titre of 1:40. In none of the 10-week-old piglets did the titre exceed the value of 1:20, but in about 25% of the piglets it reached 1:20; the half of these piglets came from two litters. In none of the piglets did the antibody level reach the negative threshold in the ELISA test during the study. No significant differences were found between the udder sections in milk antibody level by ELISA.     

Protection of gruntlings against classical swine fever virus-infection after oral vaccination of sows with C-strain vaccine

The objective of this study was to investigate the maternal protection of gruntlings derived from wild sows vaccinated orally against classical swine fever (CSF) using C-strain vaccine. Three vaccinated sows and one unvaccinated control sow were included. Challenge infection of the progeny was carried out either intranasally or by contact at the beginning of the third month of life (61-65 days post-natum). Whereas, two of three litters had maternal antibodies, the progeny of one vaccinated sow was seronegative at challenge. The progeny of the control sow, which was challenged by contact infection, developed moderate clinical signs except for one animal which became ill and died. Two gruntlings derived from the vaccinated sows also died of CSF, although one of them had a relatively high maternal antibody titre (128 ND(50)). The transient infection and partial virus shedding observed in a small number of gruntlings with maternal antibodies and the fact that one animal with maternal antibodies became ill and died confirm the incomplete maternal protection at this age. The reason for this incomplete protection is discussed. As none of the surviving gruntlings could be shown to carry CSFV or viral RNA at the end of the experiment (36 or 70 d.p.i.), it may be concluded that these animals do not represent a potential CSFV reservoir.     

非典型猪瘟

猪瘟是一种致死率高、危害严重的急性传染病 ,受到各养猪国家的关注。我国对猪瘟的防制工作十分重视 ,并提出当前应采取以免疫接种为重点的综合性防制措施。近年来典型猪瘟显然不多见了 ,但在一些地区和猪场却出现了一种非典型猪瘟。由于其缺乏猪瘟的典型症状和病变 ,易被人们误诊 ,以至滥用药物 ,盲目治疗 ,既增加了药费的支出 ,又贻误了防制时机 ,给猪场带来更大的经济损失。本文就非典型猪瘟的临床诊断、病因分析和防制措施等问题 ,作简要的介绍和探讨。1　非典型猪瘟的表现形式1 1　繁殖障碍型猪瘟主要发生于生产母猪 ,其本身呈隐性感染…