非洲猪瘟背景下的三元商品母猪养殖策略

非洲猪瘟病毒(African swine fever virus,ASFV)是一种病毒分子巨大且复杂的DNA病毒,在无有效疫苗的情况下,会引起高度传染性且通常致命的猪瘟。目前非洲猪瘟(African swine fever,ASF)导致我国母猪存栏大幅度下降,猪场引种面临了巨大的生物安全风险,采用三元商品母猪留种成为了一种较好的选择。文章结合生产实践,旨在为三元商品母猪的饲养管理和营养调控提供指导意见。     

African swine fever outbreak on a medium-sized farm in Uganda: biosecurity breaches and within-farm virus contamination

In Uganda, a low-income country in east Africa, African swine fever (ASF) is endemic with yearly outbreaks. In the prevailing smallholder subsistence farming systems, farm biosecurity is largely non-existent. Outbreaks of ASF, particularly in smallholder farms, often go unreported, creating significant epidemiological knowledge gaps. The continuous circulation of ASF in smallholder settings also creates biosecurity challenges for larger farms. In this study, an on-going outbreak of ASF in an endemic area was investigated on farm level, including analyses of on-farm environmental virus contamination. The study was carried out on a medium-sized pig farm with 35 adult pigs and 103 piglets or growers at the onset of the outbreak. Within 3 months, all pigs had died or were slaughtered. The study included interviews with farm representatives as well as biological and environmental sampling. ASF was confirmed by the presence of ASF virus (ASFV) genomic material in biological (blood, serum) and environmental (soil, water, feed, manure) samples by real-time PCR. The ASFV-positive biological samples confirmed the clinical assessment and were consistent with known virus characteristics. Most environmental samples were found to be positive. Assessment of farm biosecurity, interviews, and the results from the biological and environmental samples revealed that breaches and non-compliance with biosecurity protocols most likely led to the introduction and within-farm spread of the virus. The information derived from this study provides valuable insight regarding the implementation of biosecurity measures, particularly in endemic areas.     

A highly sensitive and specific gel-based multiplex RT-PCR assay for the simultaneous and differential diagnosis of African swine fever and Classical swine fever in clinical samples

The development and standardisation of a novel, highly sensitive and specific one-step hot start multiplex RT-PCR assay is presented for the simultaneous and differential diagnosis of African swine fever (ASF) and Classical swine fever (CSF). The method uses two primer sets, each one specific for the corresponding virus, amplifying DNA fragments different in length, allowing a gel-based differential detection of the PCR products. Universal detection of ASF and CSF virus strains was achieved through selection of primers in conserved viral genome regions. The detection range was confirmed by analysis of a large collection of isolates of the two viruses. The high specificity of the assay was proven by testing related viruses, uninfected cell line cultures and healthy pig tissues. Additional confirmatory tests of the ASF and CSF virus amplicon specificity, based on restriction endonuclease analysis with BsmA I or Ban II, respectively, are also described. The analysis of whole blood and serum samples from experimentally infected animals proved the usefulness of the method for an early diagnosis of both diseases, even before the appearance of the first clinical signs. A study of 150 positive field samples from several ASF and CSF outbreaks showed the suitability of this method for a rapid (less than five hours), sensitive and specific differential diagnosis in clinical samples. In addition, a highly sensitive and specific uniplex RT-PCR for CSFV was also developed and standardised as a powerful tool for fast and early diagnosis of the disease.     

饲料营养免疫对非洲猪瘟防控的作用

非洲猪瘟疫情的暴发对我国养猪产业造成了严重影响。尽管农业部门、科研专家和养猪工作者通过提高生物安全手段防控非洲猪瘟,对恢复我国生猪养殖数量和猪肉自给能力取得了相应效果,但随之而来的是猪群应激增加、饲料营养的有效性降低和猪群抗病力降低等问题。文章结合非洲猪瘟病毒特点和防控现状等,从饲料营养免疫的视角,分析如何减少猪群应激和提升猪群免疫力,以期为非洲猪瘟的综合防控提供思路。     

猪瘟诊断方法的研究进展

猪瘟是由猪瘟病毒引起的一种急性、发热性、接触性传染病,可引起各种年龄猪发病。随着对猪瘟病毒研究的深入,猪瘟在一定程度上得到了有效控制。但是近年来,世界各国流行的猪瘟在流行病学、临床症状和病理变化等方面出现了一些新的变化,猪瘟的防控出现了许多新的情况。我国猪瘟的发病率亦呈上升趋势,严重威胁着我国养猪业的发展,给养猪业造成了极大的经济损失。因此,建立准确的实验室诊断方法,对于预防和控制猪瘟有重要意义。本文综述了猪瘟诊断技术方面的研究进展,为猪瘟的及时诊断提供参考。     

非洲猪瘟疫苗研究的困境和展望

非洲猪瘟（ASF）目前是生猪产业最重要的猪病。因为非洲猪瘟病毒（ASFV）本身的复杂性,以及和宿主相互作用的复杂性导致ASF已经被报道一百年了,还没有商业化疫苗。理想的ASF疫苗不仅要有好的免疫保护性,更重要的是其安全性,同时如果能区分野毒感染和疫苗接种,能在适合的高质量GMP车间进行稳定低价的生产,能用于不同物种就更好了。ASF灭活疫苗研制这条道路似乎不通;亚单位疫苗、DNA疫苗、病毒活载体疫苗的免疫保护能力不足;主要包含自然缺失、传代致弱、基因工程缺失的减毒活疫苗在免疫保护方面体现了非常大的优势,但是其潜在的持续感染风险,会造成猪只的副作用,包括皮肤溃烂、关节炎,导致神经系统、呼吸系统的损伤等问题非常值得警惕。复制缺陷单周期病毒能有效地解决减毒活疫苗的安全性问题,似乎是一个值得尝试的ASF疫苗研制方向,尽管存在难以确定缺失复制相关的基因,以及难以构建能高效表达缺失基因编码蛋白,且能让单周期病毒稳定大量生产的辅助细胞系。我国针对ASFV强毒的精准剔除策略,未注册非法弱毒苗造成临床严重损失,以及一些不使用疫苗但成功从国家层面净化ASF的案例,让我们认识到针对ASF基础研究的重要性。同时至少目前阶段,ASF的防控不一定要借助疫苗,更多的要做好生物安全管控和区域ASF净化。尽管ASF疫苗研制困难重重,但针对ASF理想型疫苗的研制也应该持续进行下去,未来可能作为ASF防控的一个突破点。     

非洲猪瘟背景下猪育种策略探讨

非洲猪瘟给我国养猪业造成巨大损失,也沉重地打击了我国的猪育种工作,虽然目前非洲猪瘟已大大缓解,各核心育种场也逐渐恢复了育种工作,但非洲猪瘟并未消除,未来的育种工作将面临非洲猪瘟常态的挑战。在这样的背景下,我国的猪育种工作应做出针对性的改变,主要体现在：（1）建立严格的永久性的生物安全体系;（2）调整育种目标;（3）自动化、智能化、物联网技术的应用;（4）加快基因组选择技术应用;（5）建设高质量、高度生物安全的种公猪站;（6）利用冷冻精液技术。     

非洲猪瘟研究进展及防控措施

非洲猪瘟(African swine fever,ASF)是由非洲猪瘟病毒科、非洲猪瘟病毒属的唯一成员非洲猪瘟病毒(African swine fever virus,ASFV)引起的一种高致死率、高抵抗力、严格接触性的病毒性疾病,对所有年龄段的家猪和野猪均具有感染性。我国非洲猪瘟传入疫情的出现,对养猪生产构成严重威胁,必将冲击生猪产业的健康稳定发展。本文介绍ASF的病原、流行病学特点,并总结防控措施,以期为ASF的进一步防控提供参考。     

非洲猪瘟及禁抗背景下提高猪只免疫力的思考

非洲猪瘟（ASF）是由非洲猪瘟病毒（ASFV）引起的一种的热性、斑疹性、高度接触性的猪传染病。世界首例ASF于1909年在非洲肯尼亚被发现。由于其传染性强,且发病后致死率高,给生猪养殖带来极大的危害,且严重影响了畜牧经济的发展。特别是在全球禁抗背景下,提高猪只免疫力成为防控ASF的重要环节。文章就ASF特征、临床表现,就如何在禁抗下提高猪免疫力提出一些建议。     

猪场生物安全系统要点

建立生物安全体系是猪场防控疾病的前提,也是最经济有效的疫病防治措施。2018年我国发生非洲猪瘟以来,疫情对我国生猪养殖业带来深刻影响,在未来很长一段时间内该病都将是我国猪场的常态化疾病。非洲猪瘟疫情发生后,我国养猪业创新性地提出了系列生物安全防控技术,建立了能够有效应对疫情常态威胁的生物安全技术体系,两年多来的防控实践证明了这些生物安全防控手段的有效性。文章总结了猪场生物安全体系建设和管理中的关键环节及注意事项,希望可以为猪场非洲猪瘟防控提供参考。     

非洲猪瘟病毒核酸检测技术与应用进展

自2018年8月以来,非洲猪瘟已成为我国养猪业的头号疫病,对养猪业造成了巨大损失。基于聚合酶链式反应(PCR)的核酸检测方法具有高灵敏性和高特异性,在对非洲猪瘟的诊断、感染监控和养殖复产过程中生物安全评价等方面发挥了重要的作用。文章对常用的核酸检测技术与特点、非洲猪瘟病毒核酸检测方法的应用、核酸检测新技术展望3个方面进行了总结,以期为养猪企业在非洲猪瘟核酸检测和监测方面提供帮助。     

Serum concentrations of C-reactive protein, serum amyloid A, and haptoglobin in pigs inoculated with African swine fever or classical swine fever viruses

OBJECTIVE: To determine serum concentrations of the selected acute-phase proteins (APPs) haptoglobin, serum amyloid A (SAA), and C-reactive protein (CRP) in pigs experimentally inoculated with classical swine fever (CSF) and African swine fever (ASF) viruses. ANIMALS: 8 crossbred (Large White x Landrace) 10-week-old pigs. PROCEDURES: Pigs were allocated to 2 groups (4 pigs/group). One group was inoculated with the CSF virus Alfort 187 strain, whereas the other groupwas inoculated with the ASF virus Spain 70 isolate. Blood samples were collected at various time points. At the end of the study, pigs were euthanized and a complete necropsy was performed, including histologic and immunohistochemical analyses. RESULTS: Serum concentrations of APPs increased in pigs inoculated with CSF and ASF viruses, which suggested an acute-phase response in the course of both diseases. The most noticeable increase in concentration was recorded for SAA in both groups (up to a 300-fold increase for CSF virus and an approx 40-fold increase for ASF virus), followed by CRP and then haptoglobin, which each had only 3- to 4-fold increases. CONCLUSIONS AND CLINICAL RELEVANCE: Serum concentrations of APPs increased significantly in pigs inoculated with CSF and ASF viruses. However, differences were evident in serum concentrations of the proteins evaluated in this study.     

Prevalence of African swine fever virus and classical swine fever virus antibodies in pigs in Benue State,Nigeria

Tropical Animal Health and Production - This study investigated the prevalence of African swine fever virus (ASFV) and classical swine fever virus (CSFV) antibodies in pigs in Benue State, Nigeria....     

提高生物安全措施是养猪场防控非洲猪瘟的关键

非洲猪瘟(African Swine Fever, ASF)是由非洲猪瘟病毒(African Swine fever Virus, ASFV)引起的一种急性、烈性、高度接触性的传染病,其发病率高,死亡率可高达100%。世界动物卫生组织(OIE)将其列为必须报告动物疫病,我国将其列为一类动物疫病。由于目前并没有安全有效的疫苗,防控ASF最有效的方法是实行早期诊断、扑杀和严格的封锁隔离措施,针对养猪场则需要高度重视生物安全防控措施。根据非洲猪瘟的流行病学特征,简要综述了养猪场如何通过建立良好的生物安全屏障、切断可能传播途径、有效消毒降低潜在病原等重要措施来防控非洲猪瘟。     

非洲猪瘟病毒传播方式及控制措施

非洲猪瘟(African swine fever,ASF)是由非洲猪瘟病毒(African swine fever virus,ASFV)引起的一种急性、热性、高度传染性疫病,感染猪以发热和全身性出血为主要特征,病程短、病死率高。非洲猪瘟主要流行于非洲国家,随后相继传入西欧、南美洲、东欧,以及亚洲国家,对全球养猪业、食品安全和猪及其产品国际贸易产生了严重危害和深远影响。现结合参考文献和我国非洲猪瘟发生、控制情况,分析了非洲猪瘟病毒传播动力学、传播方式,提出防控非洲猪瘟的主要措施。     

Effect of husbandry methods on seropositivity to African swine fever virus in Sardinian swine herds

Multiple logistic regression was used on serological data collected in the context of the Sardinian African swine fever (ASF) eradication program from pig farms in the province of Nuoro, Sardinia. The monthly percentage of ASFV-positive herds decreased significantly from October 1994 through March 1996 (P < 0.001). The farm-level risk of seropositivity to African swine fever virus (ASFV) was higher in free-range farms than in partial-confinement farms (odds ratios (OR) varied between 4.9 in October 1994, and 5.7 in March 1996, P < 0.001). The risk of infection for total-confinement farms was one-fifth of the risk for partial-confinement farms in October 1994 (OR = 0.2, P < 0.001), whereas in March 1996, the estimated OR was 0.57 and not significant (upper confidence limit = 1.1). The maintenance of ASFV in Sardinia was primarily associated with free-range pig farms. The natural logarithm of the number of pigs tested per visit in a farm was positively associated with the risk of herd seropositivity (OR = 2.6, P < 0.001).     

A promising multiple-epitope recombinant vaccine against classical swine fever virus

Classical swine fever (CSF) is a highly contagious and often fatal disease of swine. It is caused by classical swine fever virus (CSFV), one of the members of the genus Pestivirus of the Flaviviridae family. The development of a safe and effective vaccine against the CSF is critical to pandemic control, this article shows a tandem-repeat multiple-epitope recombinant vaccine can protect pigs from CSFV challenge. That was composed as following: two copies each of glycoprotein E2 residues 693–707, 241–276 and 770–781, and two copies amino acid residues 1446–1460 of the non-structural protein NS2-3. In the challenge test, all of the swine vaccinated with Chinese vaccine strain (C-strain) were fully protected from a challenge with CSFV. However, after three successive vaccinations with the multiple-epitope recombinant vaccine, three out of five pigs were protected from challenge with CSFV (in terms of both clinical signs and viremia). These results demonstrate that multiple-epitope recombinant vaccine which carrying the major CSFV epitopes can induce a high level of epitope-specific antibodies and exhibit a protective capability that parallels induced by C-strain to a certain extent.     

1株非洲猪瘟病毒自然变异毒株的鉴定

非洲猪瘟(ASF)于2018年传入我国后已流行了2年有余,我国非洲猪瘟病毒(ASFV)毒株未曾出现较大变异.最近,针对我国ASF疫情放缓以及感染猪出现的低死亡率现象,我们在ASFV生态学研究中,从主动监测的样品中分离到1株源自湖北某地的ASFV自然变异株.经基因组测序发现,其EP402R基因(CD2v)和上游相邻的EP...     

Virulence of recent and former classical swine fever virus isolates evaluated by their clinical and pathological signs

The clinical diagnosis of classical swine fever (CSF) still caused problems to the veterinarians during the last decade. The primary CSF outbreak was often detected too late and, meanwhile, the virus had spread. Consequently, the recent classical swine fever virus isolates (CSFV) were suspected to be of low virulence. The purpose of the study was to quantify the virulence of four recent CSFV by evaluating the clinical and pathological signs caused by different CSFV. Pigs of the same breed and age group were inoculated intranasally with CSFV from recent epidemics in European Union (EU) member states. The CSFV used are registered in the data base of the EU Reference Laboratory for CSF and belong to different genotypes: 2.1, 2.2 and 2.3 respectively. Clinical signs of CSF were evaluated by using a score system suggested previously (Mittelholzer et al., 2000: Vet. Microbiol. 74, 293). For the evaluation of pathological lesions, a new pathological score was introduced. The four CSFV tested here were classified as moderately virulent in general, although one CSFV may cause different clinical courses, ranging from highly virulent to avirulent. This indicates the importance of additional factors in the host animal for virulence. Differences in the clinical and pathological signs between these four recent CSFV were rather minor, emphasizing that the genetic typing of CSFV is absolutely essential. Differences towards former CSFV (e.g. reference virus strain Alfort 187) were more pronounced, especially regarding the onset and duration of the disease, the occurrence of skin haemorrhages and pathological lesions of kidney, subcutis and serosae. It is concluded that clinical diagnosis of CSF is rather difficult in pigs up to 14 days post-CSFV infection using these four CSFV, emphasizing the need for careful differential diagnosis and the laboratory investigation for CSF at an early stage.