猪繁殖与呼吸综合征的防控措施探索

猪繁殖与呼吸综合征是近十几年以来发生的新型疾病,是由病毒引起的接触性传染病,对养殖场的危害日益严重。本文阐述了猪繁殖与呼吸综合症(PRRS)的病原、流行特点、剖检特点、诊断方法以及预防、控制措施,为广大的养殖户提供技术参考。     

猪繁殖与呼吸综合征研究进展及防控

《猪业科学》作为此次盛会的特约合作媒体跟踪报道大会的盛况。也使小编有幸能够近距离接触国内外从事猪繁殖与呼吸综合征前瞻性研究的专家、教授,就目前国内外猪繁殖与呼吸综合征的研究现状及未来发展等与读者一起分享。     

猪繁殖与呼吸综合征免疫的重重疑云

猪繁殖与呼吸综合征(蓝耳病)现已遍及世界各主要养猪国家和地区,成为危害养猪业最严重的传染病之一。对于蓝耳病病毒的特征及免疫,学术界已突破一系列难题,但仍存在着许许多多我们尚未知晓的玄机。因此,造成学术界和养猪行业内的争论也此起彼伏。这其中不乏有商业利益的驱使,但最终也反映了人们对蓝耳病的认识和对蓝耳病疫苗所具有的疑虑。对蓝耳病病毒病原特性,目前经常用于蓝耳病免疫的疫苗及其所存在的问题和造成这些现象的原因进行综述,以期提高人们对蓝耳病疫苗的认识,为生产实践中对蓝耳病的防治提供借鉴。     

猪繁殖与呼吸综合征的防控措施及现状分析

猪繁殖与呼吸综合征（PRRS）是当前中国乃至世界猪病防控领域的难点和热点。多年以来,针对PRRS的防控,世界范围内采取了许多措施,如加强生物安全、PRRS净化、驯化及疫苗免疫等。总体看来,经过多年的努力,各地防控PRRS取得了一定的成绩,但PRRS的防控效果仍存在很大的提升空间。本文梳理了国内外PRRS各种防控措施,以期为同行在防控PRRS的实践中提供借鉴。     

猪繁殖与呼吸综合征的监测及其防控

为评价ELISA抗体检测对蓝耳病疫情预警以及相应防控方案的可行性,对疑似存在蓝耳病疫情风险的某规模化猪场进行抗体检测。结果显示:该场猪蓝耳病抗体离散度大,S/P值≥2.6的比例占检测数的30.4%,表明该场存在蓝耳病感染风险,并通过RT-PCR检测病原得到证实。对该场母猪群及其仔猪采取活苗紧急免疫防控后,该场疫情得到有效缓解,仔猪存活率由原来的48%提高到88%。结论:蓝耳病抗体ELISA检测具有监测预警作用,采用活疫苗免疫防控蓝耳病方案是可行的。     

猪繁殖与呼吸综合征防控的措施

猪繁殖与呼吸综合征(PRRS),是由PRRS病毒(PRRSV)引起的猪的繁殖障碍和呼吸道炎症的传染病。该病临床以流产、早产、死产和产木乃伊胎以及呼吸道疾病为特征,伴随哺乳和断奶猪的死亡和     

猪繁殖与呼吸障碍综合征疫苗的研究进展

猪繁殖于呼吸障碍综合征(猪蓝耳病)一直以来是世界养猪业的头号大敌。与此同时,猪蓝耳病的疫苗也得到了长足发展。本文针对各种猪蓝耳病疫苗功能及不足进行综述,同时提出展望。1 PRRS灭活苗灭活疫苗是先大量培养致病病原(如病毒或细菌),然后通过加热或化学剂(通常是福尔马林)的方法使丧失毒力或感染性而保留良好的免疫原性制备     

浅谈猪繁殖和呼吸综合征的综合防制

猪繁殖和呼吸综合征（简称猪蓝耳病）,是８０年代后期于美国发现的一种新的有高度传染性的猪综合征,以母猪发热、厌食和流产、木乃伊胎、死产、弱仔等繁殖障碍以及仔猪的呼吸症状和高死亡率为特征。１９９０年后在欧洲大多数国家和亚洲一些地区也相继发现本病。该病给养...     

猪繁殖与呼吸综合征综合防控策略

本文主要从科学生产、加强生物安全管理、合理使用疫苗及定期监测四个方面来阐述蓝耳病的防控策略.     

浅谈猪繁殖与呼吸综合征的流行特点与防控策略

猪繁殖与呼吸综合征(PRRS)被认为是影响世界范围内猪密集生产最昂贵的疾病之一.近年来高致病性PRRS的发病率不断升高,成为困扰我国养猪业的巨大难题.本文概述了PRRS发病快、传染性强、危害较大的基本特征,阐述了全球流行病学发展史.并结合当前防控现状,提出通过重视引种,提高风险防控认识,强化疫苗免疫等加强生物安全管理及...     

非洲猪瘟形势下猪流行性腹泻的防控措施

自2018年第一例非洲猪瘟疫情报道至今已经两年多了.为了快速扩繁猪群,许多清空场及新建场不得不大量外购来源复杂后备猪进群.因此,猪场在对猪流行性腹泻的防控上面临着更大的挑战.文章介绍了病毒性腹泻暴发的原因、防控难点和综合防控措施,期望为养殖业同人在实际生产中,科学防控猪流行性腹泻提供一定的参考借鉴.     

Effects of porcine reproductive and respiratory syndrome vaccination in breeding-age animals

Little is known about the safety and efficacy of extra-label use of the modified live porcine reproductive-and-respiratory syndrome (PRRS) virus vaccine in gestating sows. Our purpose was to determine the impact of vaccination on reproductive performance in 54 herds in Ontario, Manitoba (Canada) and the mid-western United States that were PRRS-positive, PRRS-negative, or concurrently affected by an outbreak of PRRS when initially vaccinated. Majority-vaccinated herds vaccinated ≥50% but <100% of sows at one time, and limit-vaccinated herds vaccinated <50% of sows at one time. Most majority-vaccinated herds did not vaccinate sows in late gestation, and none vaccinated during the initial PRRS outbreak. Numbers of pigs born alive and weaned decreased when pregnant sows were vaccinated. The effect of vaccination on productivity in the gestation following vaccination depended on the vaccination protocol.     

猪回肠炎的综合防控措施

猪回肠炎是由胞内劳森氏菌引起的,以猪回肠、盲肠、结肠黏膜呈腺瘤样增生为主要特征的肠道传染病~([1])。在后备和成年猪群主要表现为急性猝死和血痢,在6～20周龄的育肥猪主要表现为腹泻、生长整齐度变差等。当前,我国养猪业正处于受非洲猪瘟影响以及饲料禁抗双重压力下的关键时期,为防止在此期间猪回肠炎对猪场造成更大损失,猪场管理者应加强对回肠炎的综合防控措施。     

猪圆环病毒病流行的新变化与综合防控措施

猪圆环病毒病是由猪圆环病毒感染后引起的一种免疫抑制性传染病.不同阶段的猪感染后可能表现不同的临床症状,而且容易发生连续感染,增加治疗难度,给猪场造成巨大损失.文章从猪圆环病毒病的病原、流行病学、临床症状与病理变化、诊断方法和防控措施进行了概述,以期为广大养猪生产者提供借鉴.     

猪高致病性蓝耳病的流行特点及防制措施

近两年来,我国部分地区不同程度地发生多重感染及混合感染引起猪体温升高到40．5℃以上的“高热病”。该病以发热、不食、大便干燥、皮肤发红、眼分泌物多、结膜炎和出现呼吸道症状为主要特征。病程长达7d以上,发病率和死亡率极高,并迅速向周边地区蔓延,给养猪业造成了巨大的经济损失。经农业部组织有关专家、有关单位开展流行病学调查、病原分离鉴定、动物实验室等科技攻关,发现了高致病性蓝耳病变异病毒（猪繁殖与呼吸综合症变异病毒）。2007年4月,农业部正式确定为“高致病性蓝耳病”。     

Acute phase response in porcine reproductive and respiratory syndrome virus infection

This study was focused on the changes observed in the serum concentration of haptoglobin (Hp), C-reactive protein (CRP), serum amyloid A (SAA) and Pig-major acute protein (Pig-MAP), during experimental porcine reproductive and respiratory syndrome virus (PRRSV) infection and in their relationship with the expression of interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α). Hp and Pig-MAP serum levels were increased at 10 dpi, but CRP and SAA showed a delayed and highly variable increase. All three proinflammatory cytokines were poorly expressed, and only a mild increase in IL-1β was observed at 7 dpi. The increased expression of Hp coincided with the light enhancement observed in both IL-6 and TNF-α, and might be related with an increased expression of IL-10. The low expression of TNF-α might point to a possible mechanism of viral evasion of host-immune response. This issue and the delayed expression of CRP and SAA should be taken into account in future studies about modulation of the immune response by PRRSV infection.     

猪繁殖与呼吸综合征的诊断与防制

某猪场发生猪繁殖与呼吸综合征（PRRS），由于基层兽医工作者诊断本病经验不足，误诊为猪附红细胞体病，既消费了不少药物，也延误了不少时间，加重了经济损失。疫病确诊后，采取了合理的措施，很快得到了控制。     

Systemic and mucosal immunity induced by attenuated Salmonella enterica serovar Typhimurium expressing ORF7 of porcine reproductive and respiratory syndrome virus

Oral administration of attenuated Salmonella vaccine may provide valuable advantages such as low cost, easy preparation, and safety. Attenuated Salmonella vaccines also serve as carriers of foreign antigens and immunomodulatory cytokines. Presently, an attenuated Salmonella enterica serovar Typhimurium strain was used as a carrier for open reading frame 7 (ORF7) protein of porcine reproductive and respiratory syndrome virus (PRRSV), a swine pathogen of significant global economic importance. Initially, an attenuated S. enterica serovar Typhimurium expressing ORF7 gene derived from PRRSV Korean isolate was constructed. Following oral administration of a single dose of the attenuated Salmonella vaccine expressing PRRSV ORF7, humoral and cell-mediated immune responses specific for ORF7 were induced at both systemic and mucosal sites including spleen, mesenteric lymph node, Peyer's patch, and laminar propria, as evaluated by determining serum ORF7-specific IgG and mucosal IgA responses, as well as Th1- and Th2-type cytokine production from antigen-stimulated T cells. The induced humoral responses were sustained for at least 12 weeks post-immunization. In particular, the immunized mice displayed immune responses to both the foreign ORF7 antigen and Salmonella itself. The results indicate the value of attenuated S. enterica serovar Typhimurium as an oral carrier of PRRSV antigenic proteins to induce effective systemic and mucosal immunity.     

Associations between genetics, farm characteristics and clinical disease in field outbreaks of porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome (PRRS) is a disease of domestic swine characterized by exceptionally high clinical variability. This study addresses the question of whether clinical variability in PRRS results from (a) genetic variation among viral isolates and/or (b) variation in management practices among farms on which isolates are found. Genetic data (open reading frame 5 gene sequences) and data on farm characteristics and associated clinical disease signs were collected for 62 PRRS virus (PRRSV) field isolates, representing 52 farms. Clinical disease signs were interrelated — confirming that a true reproductive syndrome exists (involving abortions, infertility in sows, deaths of sows and preweaning mortality).

Pairs of farms experiencing deaths in their sow populations also tended to share viral isolates which were more similar to one another than expected by chance alone. This implies that sow death (one of the more-severe manifestations of PRRS) is under genetic influence. Large herd size was a significant risk factor for the death of sows and for respiratory disease in nursery pigs. All-in–all-out management practices in the nursery were protective against reproductive signs in the sow herd. All-in–all-out management practices in the finishing stages of production were protective against respiratory disease in nursery pigs — but were paradoxically associated with an increased risk of infertility in sows. These results suggest that farm-management practices can also influence which PRRS clinical signs are manifested during an outbreak. In general, signs associated with PRRS appear to result from a combination of genetic factors and herd-management characteristics. The relative contributions of these two influences differ depending on the specific clinical sign in question.     

Association of porcine circovirus 2 with porcine respiratory disease complex

A retrospective study was performed on natural cases of porcine respiratory disease complex (PRDC) to determine the association and prevalence of PRDC with porcine circovirus 2 (PCV2) and other co-existing pathogens in Korea. Histologically, alveolar septa were markedly thickened by infiltrates of mononuclear cells. Moderate to marked multifocal peribronchial and peribronchiolar fibrosis were present and often extended into the airway lamina propria. Among the 105 pigs with PRDC, 85 were positive for PCV2, 66 were positive for porcine reproductive and respiratory syndrome virus (PRRSV), 60 were positive for porcine parvovirus (PPV), and 14 were positive for swine influenza virus (SIV). There were 80 co-infections and 25 single infections. A co-infection of PCV2 with another additional bacterial pathogen is frequently diagnosed in PRDC. The combination of PCV2 and Pasteurella multocida (38 cases) was most prevalent followed by PCV2 and Mycoplasma hyopneumoniae (33 cases). The consistent presence of PCV2, but lower prevalence of other viral and bacterial pathogens in all pigs examined with PRDC, has led us to speculate that PCV2 plays an important role in PRDC.