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.     

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...     

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。     

Correlation of cell surface marker expression with African swine fever virus infection

The expression of surface markers on African swine fever virus (ASFV) infected cells was evaluated to assess their involvement in infection. Previous findings indicated CD163 expression was correlated with ASFV susceptibility. However, in this study the expression of porcine CD163 on cell lines did not increase the infection rate of these cells indicating other factors are likely to be important in determining susceptibility to infection. On adherent porcine bone marrow (pBM) cells the expression of CD45 was strongly correlated with infection. CD163 and CD203a expression correlated at intermediate levels with infection, indicating cells expressing these markers could become infected but were not preferentially infected by the virus. Most of the cells expressing MHCII were infected, indicating that they may be preferentially infected although expression of MHCII was not essential for infection and a large percentage of the infected cells were MHCII negative. CD16 showed a marked decrease in expression following infection and significantly lower levels of infected cells were shown to express CD16. Altogether these results suggest CD163 may be involved in ASFV infection but it may not be essential; the results also highlight the importance of other cell markers which requiring further investigation.     

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。     

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...     

臭氧在非洲猪瘟防控上的合理利用

非洲猪瘟病毒抵抗力强、危害严重,臭氧须合理利用,才能发挥其在猪场非洲猪瘟防控消毒中的相应效果。     

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。     

非洲猪瘟病毒入侵细胞机制的研究进展

病毒进入宿主细胞的机制决定了病毒的趋向性和发病机理,病毒感染细胞包括吸附、穿入、脱壳、复制、组装及子代病毒颗粒的释放等步骤,对病毒入侵机制研究可以为开发有针对性的预防策略提供思路。非洲猪瘟病毒作为一种有囊膜双链DNA病毒,其入侵宿主细胞的机制与其他病毒有一定的相似之处,同样也有其特殊性。目前,人们对非洲猪瘟病毒与宿主细胞相互作用,特别是入侵机制的了解仍然非常有限。为此,本文就ASFV入侵细胞的有关研究进展进行了综述,以期为非洲猪瘟病毒致病机制相关研究提供参考。     

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。     

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.     

Risk factors of African swine fever virus in suspected infected pigs in smallholder farming systems in South-Kivu province,Democratic Republic of Congo

BackgroundAfrican swine fever (ASF) is an infectious viral disease of domestic pigs that presents as a hemorrhagic fever, and for which no effective vaccine is available. The disease has a serious negative social and economic impact on pig keepers. There is limited information on the potential risk factors responsible for the spread of ASF in South Kivu.ObjectiveThe aim of this study was to determine the potential risk factors associated with ASF infection in suspected ASF virus (ASFV)-infected pigs.MethodsWe sampled whole blood from 391 pigs. Additionally, 300 pig farmers were interviewed using a structured questionnaire. Viral DNA was detected by using the real-time polymerase chain reaction technique.ResultsThe majority of pigs sampled, 78% (95% confidence interval [CI], 74.4–82.6), were of local breeds. Over half, 60.4% (95% CI, 55.5–65.2), were female, and most of them, 90.5% (95% CI, 87.6–93.4), were adult pigs (> 1 year old). Viral DNA was detected in 72 of the 391 sampled pigs, indicating an overall infection rate of 18.4% (95% CI, 14.5–22.4). Multivariable logistic regression analysis revealed several risk factors positively associated with ASFV infection: feeding with swill in pen (odds ratio [OR], 3.8; 95% CI, 2.12–6.77); mixed ages of pigs in the same pen (OR, 3.3; 95% CI, 1.99–5.57); introduction of new animals to the farm (OR, 5.4; 95% CI, 1.91–15.28). The risk factors that were negatively (protective) correlated with ASFV positivity were the presence of male animals and the use of an in-pen breeding system.ConclusionLocal pig farmers should be encouraged to adopt proper husbandry and feeding practices in order to increase the number of ASF-free farms.     

非洲猪瘟背景下复养的消毒工作初探

自2018年8月以来蔓延的非洲猪瘟疫情给我国养猪业造成了巨大损失,生猪供应缺口凸显,猪价整体高位运行。安全顺利复产是规模猪场的优先选择,但由于准备不足、匆忙复产而导致失败的案例甚多;在目前没有相关疫苗的情况下,完善生物安全体系、彻底清除猪场内外残余病毒是规模猪场非洲猪瘟背景下复产的先决条件。笔者团队通过制订复养程序,指导某猪场进行非洲猪瘟复养消毒,各区域检测、复检为阴性后引入180头保育猪作为哨兵猪饲养2个多月,病原学和血清学检测结果均为阴性,复养初步成功。     

非洲猪瘟的防控关键技术

非洲猪瘟传入我国以来,给我国养猪业造成了巨大的损失。非洲猪瘟可防可控,文章从消灭传染源、切断传播途径、保护易感猪群方面介绍了构建猪场生物安全体系的防控技术。