猪繁殖与呼吸综合征血清学调查

猪繁殖与呼吸综合征（ＰＲＲＳ）是１９８７年首发于北美和欧洲的一种猪的新传染病〔１〕,其病原为猪繁殖与呼吸综合征病毒〔２,３〕。该病毒在国际病毒分类委员会第六次报告中（１９９６）,归属于冠状病毒科动脉炎病毒属,系正股单股ＲＮＡ病毒〔４〕。该病主要症状为...     

猪繁殖与呼吸综合征的血清学调查

利用ＰＲＲＳＶ ＥＬＩＳＡ诊断试剂盒对西宁、大通的部分种猪场的２２０份血清进行ＰＲＳＶ的血清学调查,共检出阳性７６份,阳性率为３４．５５％,表明该病已在我省几个主要猪场中广泛流行。     

德州市猪繁殖呼吸综合征（PRRS）血清学调查

德州市猪繁殖呼吸综合征（ＰＲＲＳ）血清学调查李春生杨绍曾范伟兴①陈静②李学海刘万成①缪典祥王景波（山东省德州市畜牧局２５３０００①②山东省畜牧兽医总站山东农业大学ＰＲＲＳ是近几年来新发现的一种猪的病毒性传染病,病原是ＰＲＲＳＶ,该病主要造成母猪的繁殖...     

猪繁殖与呼吸综合征的血清学调查

猪繁殖与呼吸综合征（PRRS）是由PRRSV引起的一种接触性传染病。为了了解PRRS在我省几个较大种猪场中的流行情况，我们于2004年6月份利用ELISA诊断试剂盒进行了PRRS调查。报告如下。     

猪繁殖与呼吸综合征血清学调查

猪繁殖与呼吸综合征（PRRS）是以引起母猪发热、厌食和流产、死产、木乃伊胎、弱仔等繁殖障碍以及仔猪的呼吸道症状和高死亡率为特征的一种接触性传染病，各种日龄的猪均可感染。其主要危害是造成流产数和不育发生率增加，生长率下降，猪的死亡率增加，饲料转化率下降等。     

广西猪繁殖与呼吸综合征血清学调查

猪繁殖与呼吸综合征(PRRS)俗称蓝耳病,是80年代末期发现的以妊娠母猪流产、早产、死胎、木乃伊胎和弱仔及仔猪呼吸道症状高死亡率为主要特征的一种新的病毒性传染病.1987年首先在美国发现本病,而后世界各地陆续有报道本病的流行暴发.我国大陆在1996年初首次报道首例PRRS.目前,PRRS已在我国某些地区流行,并已造成严重的经济损失.为摸清PRRS在我区的感染情况,1999-2000年两年间我们应用ELISA方法对来自全区各地的猪血清进行PRRS监测.现将结果报道如下:     

甘肃省集约化猪场猪繁殖与呼吸综合症的血清学调查

猪繁殖与呼吸综合症（ＰＲＲＳ）是一种新近发现的猪病毒性疾病，其特征为各种年龄猪均可感染发病。主要临床症状以发病猪不食、嗜睡、体温升高；繁殖母猪受精率低下；妊娠母猪发生早产、晚期流产、死胎、弱胎及木乃伊胎；哺乳母猪泌乳不足，严重影响新生仔猪的生长发育，甚至死亡；种公猪性功能下降，影响精液质量和精子活力；仔猪和育肥猪表现呼吸系统症状，呼吸困难和急促，呈间质性肺炎，耳部及肢体皮肤发绀。该病自１９９５年１１月在我国发生以来，已在全国大部分省市出现，危害十分严重。为了查清该病在甘肃省的感染和流行情况，我ｗ…     

山西省猪繁殖与呼吸综合征血清学调查

猪繁殖与呼吸综合征(PRRS)是由猪繁殖与呼吸综合征病毒(PRRSV)所致的猪的一种病毒性传染病,以引起母猪发热、厌食和流产、产死胎、木乃伊胎、弱仔等繁殖障碍以及仔猪的呼吸道症状和高死亡率为特征。各种日龄的猪均可感染,其主要危害是造成流产数和不育发生率增加,生长率下降,猪的死亡率增加,饲料转化率下降等。     

河北省猪繁殖与呼吸综合征血清学调查

应用ELISA试剂盒对2008年9月至2009年3月河北省不同地区规模化猪场猪繁殖与呼吸综合征(PRRS)的流行情况进行了血清学调查。共检测血清1 663份,检出阳性血清882份,阳性率53.04%。其中非免疫猪场861份血清,阳性血清289份,阳性率33.57%;免疫PRRSV疫苗的猪场血清802份,阳性血清593份,阳性率73.94%。非免疫猪场母猪阳性率为45.81%,仔猪为33.86%。提示河北省存在猪繁殖与呼吸综合征,应采取多种措施积极防制。     

猪繁殖和呼吸综合征油乳剂灭活苗的研制

使用猪场自行分离的PRRSV,进行细胞转瓶培养,收获病毒液后灭活,乳化制成油乳苗,各项指标检测均合格,并且免疫试验效果较好.     

Genetic analysis of reproductive performance in sows during porcine reproductive and respiratory syndrome(PRRS) and porcine epidemic diarrhea(PED)outbreaks

Background: Porcine reproductive and respiratory syndrome(PRRS) is one of the most infectious swine diseases in the world, resulting in over 600 million dollars of economic loss in the USA alone. More recently, the USA swine industry has been having additional major economic losses due to the spread of porcine epidemic diarrhea(PED).However, information regarding the amount of genetic variation for response to diseases in reproductive sows is still very limited. The objectives of this study were to identify periods of infection with of PRRS virus(PRRSV) and/or PED virus(PEDV), and to estimate the impact their impact on the phenotypic and genetic reproductive performance of commercial sows.Results: Disease(PRRS or PED) was significant(P 0.05) for all traits analyzed except for total piglets born.Heritability estimates for traits during Clean(without any disease), PRRS, and PED ranged from 0.01(number of mummies; Clean and PED) to 0.41(abortion; PED). Genetic correlations between traits within disease statuses ranged from-0.99(proportion born dead with number weaned; PRRS) to 0.99(number born dead with born alive;Clean). Within trait, between disease statuses, estimates ranged from-0.17(number weaned between PRRS and PED) to 0.99(abortion between Clean and PRRS).Conclusion: Results indicate that selection for improved performance during PRRS and PED in commercial sows is possible and would not negatively impact performance in Clean environments.     

Molecular characterization of recent Korean porcine reproductive and respiratory syndrome (PRRS) viruses and comparison to other Asian PRRS viruses

Twenty-eight PRRS viruses (PRRSVs) isolated from various pig farms in Korea between 2002 and 2003 were sequenced for open-reading frame (ORF) 5 and/or full-length genome and compared with numerous PRRSVs reported from North America, Europe and Asia. All Korean isolates examined were genetically of the North American genotype. The ORF5 sequence of one isolate was identical to Ingelvac PRRS MLV vaccine virus. ORF5 nucleotide sequence divergence of the remaining 27 Korean PRRSVs from VR-2332, the prototype of the North American PRRSV and parental strain of the MLV vaccine virus, ranged from 1.3% to 12.9%, which corresponded to 2.0% to 14.9% divergence at the amino acid level, raising a concern on the efficacy of the MLV vaccine. Phylogenetic analyses of ORF5 and/or full-length sequences revealed that the Korean PRRSVs formed a clade distinct from PRRSVs reported from other Asian countries (China, Taiwan, Japan, and Thailand). Our study demonstrated that PRRSVs of the North American genotype were introduced to the Korean swine population some time ago and have evolved independently from PRRSV in other Asian countries, suggesting that geographic separation might influence the molecular evolution of PRRSV. This should be taken into consideration when a national PRRS prevention and control policy for international trade is established.     

Risk factors for infection of sow herds with porcine reproductive and respiratory syndrome (PRRS) virus

In 1992, the porcine reproductive and respiratory syndrome virus (PRRSV) of European type (PRRSV-EU) was introduced in Denmark. By 1996, the virus had spread to approximately 25% of the Danish herds. In January 1996, a modified-live vaccine based on the American type of the virus (PRRSV-US) was used in replacement boars for Danish artificial insemination (AI) centres and from July 1996, the vaccine was used in PRRSV-EU infected herds for prevention of disease. Soon after vaccine introduction, PRRSV non-infected herds experienced outbreaks of disease due to infection with PRRSV-US. In this study, we investigated the risk factors (biosecurity level, animals, exposure from PRRSV-US-infected neighbour herds, semen, herd size, pig density and herd density) for infection with PRRSV-US in a cohort of 1071 sow herds; we used a nested case-control study. The retrospective observation period lasted from June 1996 (when they all were non-infected) to October 1997. Seventy-three non-vaccinated, closed sow herds became infected with the vaccine strain during this period. Each case herd was matched with two control herds from the cohort (controls had not been infected at the time of infection in the case herds). The data were analysed using a Cox-regression model. The hazard of infection increased significantly with exposure from PRRSV-US-infected neighbouring herds, purchase of animals from herds incubating PRRSV-US infection, increasing herd size and purchase of semen from boars at PRRSV-US-infected AI centres. The results are consistent with the modified-live vaccine strain spread to other herds by trade with animals and semen and by neighbour (area) transmission. We suggest that virus spread by aerosols was a frequent mode of transmission.     

Sow performance in an endemically porcine reproductive and respiratory syndrome (PRRS)-infected farm after sow vaccination with an attenuated PRRS vaccine

The objective of this field study was to evaluate in an endemically porcine reproductive and respiratory syndrome (PRRS) virus-infected farm the reproductive performance of sows after their vaccination with a PRRS attenuated vaccine. In a farrow-to-finish pig farm with history of endemic PRRS virus infection, a total of 200 gilts and sows were used. They were divided in 2 groups of 100 animals. The first group was used as untreated controls, while the animals of the second group were vaccinated against PRRS virus using the attenuated Porcilis PRRS vaccine (Intervet International, The Netherlands) based on European strain. All health and reproductive parameters were recorded from the time of vaccination up to next weaning. No adverse systemic or local reactions or side effects relative to vaccination were noted. Compared to controls, vaccinated sows showed significantly improved farrowing rate (89% versus 78%) and a tendency for fewer returns to oestrus, particularly those at irregular intervals. Fewer sows farrowed prematurely and showed post-partum dysgalactia syndrome, but more live pigs were born and weaned in each litter after vaccination. It was concluded that vaccination of sows with Porcilis PRRS attenuated vaccine in farms with endemic PRRSV infection has beneficial effects on their health and fertility.     

Effect of orally administered Lactobacillus casei on porcine reproductive and respiratory syndrome (PRRS) virus vaccination in pigs

The purpose of this study was to determine whether intranasal/oral administration of probiotics can assist vaccination efficacy against an important swine pathogen, porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV). A controlled challenge trial was performed employing: (a) pigs vaccinated against PRRS and treated with a Lactobacillus casei, (b) pigs vaccinated against PRRS only, (c) pigs treated with L. casei only, and (d) pigs neither vaccinated against PRRS nor treated with L. casei. All pigs were challenged intranasally with a wild PRRSV strain. There was no difference in clinical signs or rectal temperature among the four groups. However, pigs that received L. casei gained significantly more weight than pigs that did not. Vaccinated pigs did not gain more weight than nonvaccinated pigs. Vaccinated groups had significantly fewer viraemic pigs on days post-challenge 4, 11 and 17 than nonvaccinated groups of pigs. There was no effect of probiotic on prevalence or duration of viraemia. Among viraemic pigs, there was no significant difference in mean log base(10) titer of PRRS virus among groups. These results suggest that orally administered L. casei does not affect immune response in such a way as to affect PRRS viraemia or nasal shedding. However, it still appears to provide significant benefit when administered during vaccination as indicated by the higher bodyweight gain following PRRS virus infection.     

猪的繁殖障碍性疾病的血清学调查

猪的繁殖障碍是以临诊表现为母猪早产、流产、产死胎和木乃伊胎等一类疾病的统称。目前是养猪业面临的一个非常棘手的问题 ,一般临诊情况下很难做出非常明确的诊断。因为引起母猪繁殖障碍的原因很多而且错综复杂 ,除了生理性、营养性和饲养管理的因素外 ,由疾病引起的猪繁殖障碍越来越突出。在病毒性疾病方面包括猪繁殖与呼吸综合征、伪狂犬病、日本乙型脑炎、猪细小病毒、猪瘟等 ;细菌性疾病包括布鲁氏菌病、钩端螺旋体和衣原体 ;寄生虫能引起繁殖障碍的有弓形虫和猪冠尾线虫。当前在病毒性疾病中主要以猪繁殖与呼吸综合征、伪狂犬病、猪瘟…