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。     

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...     

Experimental infection of pigs with different doses of the African swine fever virus Armenia 07 strain by intramuscular injection and direct contact

We experimentally infected pigs with the African swine fever virus (ASFV) Armenia 07 strain (genotype II) to analyze the effect of different dose injections on clinical manifestations, virus-shedding patterns, histopathology, and transmission dynamics by direct contact. Each three pigs and four pigs were injected intramuscularly with 0.1 fifty percent hemadsorbing doses (HAD₅₀)/ml, 10¹ HAD₅₀/ml and 10⁶ HAD₅₀/ml of ASFV Armenia 07 strain, respectively. Each two of three pigs injected with 0.1 HAD₅₀/ml and 10¹ HAD₅₀/ml died by 10 days post inoculation. All pigs had a gross lesion of splenomegaly. Perigastric and renal lymph nodes were enlarged and resembled blood clots in nine of ten pigs. It was revealed that 0.1 HAD₅₀/ml of this ASFV was sufficient to infect healthy pigs by intramuscular injection and caused sub-acute lethal disease. For the transmission study, two 8-week-old pigs were injected intramuscularly with 10³ HAD₅₀/ml of the same virus. Each of the experimentally inoculated pigs was co-housed with two 8-week-old naive pigs. All contact pigs exhibited clinical manifestations at 6 or 7 days after the experimentally inoculated pigs developed pyrexia. These findings suggest that this strain may spread slowly within a herd. Histologically, lymph nodes resembled blood clots were formed by severe blood absorption and followed hemorrhage result of disruption of the lymphoid sinus filling with absorbed red blood cells. The severity of the gross and histological lesions depended on duration after infection, regardless of the difference of injection doses in this study.     

An immunohistochemical study of the tonsils in pigs with acute African swine fever virus infection

An immunohistochemical study of the tonsils was carried out to gain further insight in the pathogenesis of acute African swine fever (ASF). Twenty-one pigs were inoculated by intramuscular route with a highly virulent isolate of ASF virus and painlessly killed at 1-7dpi. Viral antigen was highly distributed in the tonsil from 3 to 4dpi and an increase in the number of monocyte-macrophages was very evident at the same days post inoculation. This phenomenon was observed together with an increase of the expression of proinflammatory cytokines (Tumour necrosis factor alpha and Interleukin-1 alpha) and the apoptosis of lymphocytes studied by the terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) technique and haemorrhages. With these results, we can conclude that the tonsil is suffering similar lesions than those observed in other lymphoid organs in acute African swine fever, even when the route of inoculation is the intramuscular and not oral-nasal.     

吸血性节肢动物在非洲猪瘟病毒传播过程中可能扮演的角色

非洲猪瘟自2018年冬季从国外传入,给国内的生猪产业造成毁灭性打击,已造成大量生猪死亡和众多养殖户恐慌.尽管非洲猪瘟已被世界动物卫生组织列为法定上报疾病之一,但是市面上尚无有效的治疗药物和疫苗,故国际上针对该病的防制措施仍停留于消灭传染源、切断传播途等物理防御.据文献记载,非洲猪瘟病毒可由某些吸血性节肢动物所传播,故清...     

Review of African swine fever outbreaks history in South Africa: From 1926 to 2018

The article reviews the outbreaks and distribution of African swine fever (ASF) in South Africa since the first probable outbreak that occurred in the Koedoesrand Ward in 1926. Retrospective data on the ASF outbreaks in South Africa were obtained from the World Organisation for Animal Health (OIE) disease database and the South African veterinary services annual reports in addition to published articles and online sources. South Africa has experienced many outbreaks that can be divided into 2 time periods: the period before the development of the OIE diseases database (1993) and the period after. More than 141 outbreaks of ASF were reported during the first period. Since the development of OIE disease database, 72 outbreaks directly involving 2968 cases, 2187 dead and 2358 killed pigs mainly in smallholder pig farms were reported. The median number of cases for a given ASF outbreak is 17, but in 50% of outbreaks no pigs were killed for prevention. The most important ASF outbreak was reported in April 2014 in the Greater Zeerust district (North West province) involving 326 cases and 1462 killed pigs. However, the outbreak with highest mortality involving 250 pigs was reported in 2016 (Free State province). According to phylogenetic analysis, nine p72 genotypes (I, III, IV, VII, VIII, XIX, XX, XXI and XXII) have been identified in South Africa. Season-wise, more outbreaks were recorded during summer. It was also observed that the OIE disease database could contain errors that would have been introduced through compiled forms at country level. Spatiotemporal studies on ASF outbreaks in South Africa are therefore required in order to assess statistically and quantitatively the clustering of outbreaks over space and time.     

非洲猪瘟场复养成功的前提条件与关键技术措施

非洲猪瘟传入我国后,对生猪行业造成了非常不利的影响。生猪的存栏量和出栏量均出现了大幅下降,为了恢复生猪产能,保障猪肉供应,复养刻不容缓。笔者通过对猪场风险评估,对发病原因、清洗与消毒、硬件改造与升级、环境和水体检测、哨兵猪的选择与管理以及关键技术措施等进行总结与集成,并将其利用指导了3个感染过非洲猪瘟的猪场成功复养,现将这些措施的主要内容总结如下几点,供行业主管部门和养猪场(户)参考。     

常态化饲料生产企业非洲猪瘟防控措施浅议

当前我国非洲猪瘟疫情防控形势总体稳定,但是疫情隐患依然较大.非洲猪瘟病毒在饲料原料中存活时间较长,并可通过饲料或原料组分进行传播.作为饲料生产企业,必须树立抓生产和防疫情并重的生物安全意识,规范饲料生产企业非洲猪瘟防控操作流程,做到科学有效防控.本文总结了饲料生产企业非洲猪瘟防控风险关键点和传播途径,并初步探索出一套比...     

非洲猪瘟防控策略

我国对非洲猪瘟（ASF）的防控工作取得了阶段性成果,但疫情依然严峻,生猪稳产保供仍面临较大压力。文章通过了解非洲猪瘟防控现状和兽医队伍体系现状以及机构改革后非洲猪瘟防控工作存在的不足,分析了非洲猪瘟防控工作存在的问题,提出如下建议：1）重点加强中小规模养殖场（户）疫情防控工作;2）加强生猪调运监管;3）加强生猪屠宰监管。     

三类常用消毒剂对非洲猪瘟病毒灭活效果的评价

为评价戊二醛类、酚类、含氯类常用消毒剂对非洲猪瘟病毒(ASFV)的灭活效果,参考OIE参考实验室相关操作流程,基于畜禽栏舍、运载工具、器具消毒目的,根据说明书标明的浓度范围选择低、中、高3个工作浓度,与ASFV分别在4℃和20℃条件下作用30 min,10倍连续稀释后接种猪肺泡巨噬细胞,同时加入猪红细胞,培养观察红细胞...     

非洲猪瘟检测中的常见问题与分析

实验室检测是非洲猪瘟防控中的重要一环，但实验室检测不是仪器与试剂盒的简单叠加，是“人、机、料、法、环”多方面结合后的有效输出。在实验室广泛普及的同时，实验室的管理、质控、结果分析、报告解读及临床指导是重中之重。结果的正确解读及与临床信息的对接是其价值所在，临床及实验室的有效结合是综合诊断的基础。     

非洲猪瘟五级生物安全防控法的实践

2018年8月,辽宁暴发国内首例非洲猪瘟(ASF)疫情,短短数月,疫情席卷全国,养猪业一片哀鸿。这注定了整个养猪业的未来是艰辛且坎坷的。笔者作为一名集团公司区域兽医负责人,负责40 000头自繁自养母猪群的健康管理,通过我们的不懈努力,2019年全年,4万头自繁自养母猪群、13个养殖场未发生一例疫情。在一年多的防控非洲猪瘟斗争中,笔者也总结了一套特色的非洲猪瘟防控的体系方案。     

非洲猪瘟病毒VP73结构蛋白表达及鉴定

根据GenBank登录的非洲猪瘟病毒(ASFV) VP73基因序列,人工合成VP73主要抗原表位区基因片段,克隆至pUC57载体中.设计1对引物,PCR扩增获得429 bp的VP73基因片段;将VP73基因片段使用EcoRI和SalI酶切后亚克隆至表达载体pGEX-KG,经PCR、酶切、测序鉴定挑选阳性克隆,转化至表达菌株BL21 (DM3)中,进行体外诱导表达,SDS-PAGE和Western blot分析蛋白表达及其活性.结果显示,成功构建表达重组载体pGEX-KG-VP73,对该重组载体进行诱导,有效表达了41 ku重组蛋白,表达量约占菌体总蛋白的17％,Western blot分析证实该蛋白具有良好反应原性.     

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。     

规模猪场防控非洲猪瘟的生物安全措施

猪场的生物安全措施对该场的疫病预防和控制起到了非常重要的作用。文章介绍了在非洲猪瘟背景下,猪场需要在人员生物安全意识、猪群健康、猪场入口处、猪场出口处、猪场车辆管理等方面需要采取的一系列生物安全措施。供大家参考,以期提升猪场的生物安全管理水平,提高猪场疫病预防控制能力。     

非洲猪瘟形势下我国养猪业该何去何从

非洲猪瘟是由非洲猪瘟病毒感染家猪或野猪后引发的一种恶性传染病,该疫病在中国的暴发给整个养猪业造成了毁灭性的打击。然而,目前虽有报道称已经有科研单位研制出非洲猪瘟疫苗,但距离其实际应用于生产仍需要相当长的时间。中国是全球最大的猪肉生产和消费国,非洲猪瘟疫情在我国的快速传播使我国生猪产能遭受重创,直接导致猪肉供求失衡、猪肉价格翻番、猪肉市场异动。因此,文章从非洲猪瘟的传播方式、对非洲猪瘟相对有效的防控措施等方面探讨在非洲猪瘟形势下我国养猪业该如何维持产能、如何走好养殖之路。     

Entry of African swine fever virus into Vero cells and uncoating

African swine fever virus (ASFV) enters Vero cells by adsorptive endocytosis [Valdeira, M.L., Geraldes, A., 1985. Morphological study on the entry of African swine fever virus into cells, Biol. Cell. 55, 35–40]. Electron microscopy of a lysosomotropic drug-controlled penetration indicated that this step takes place in the endosomes, after fusion between the viral envelope and the limiting membrane of the endosome. Inhibition studies with colcemid, cytochalasin B, sodium azide, dinitrophenol, lysosomotropic weak bases, and the ionophore monensin, showed that the virus uptake is largely independent of cytoskeletal and lysosomal function, but dependent on oxidative phosphorylation. Some protease inhibitors inhibited viral replication at an early step, indicating that the initiation of infection depends on a viral proteolytic cleavage.     

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。