A seroepizootiologic study of vomiting and wasting disease virus in pigs

Summary Neutralizing antibodies to Vomiting and Wasting Disease virus were found in 95 per cent of the sera collected from Belgian sows at slaughter. Piglets suckled by immune sows and kept in isolation acquired maternal antibodies; these had disappeared in all the animals at the age of 15 weeks. Most pigs had lost their maternal antibodies at the age of 11 or 12 weeks (respectively 57 per cent or 86 per cent). A serologic study on two conventional breeding farms showed that this passive immunity was replaced by active immunity between the ages of 8 and 16 weeks. No clinical disturbances appeared to be associated with the infection. The present data indicate that Vomiting and Wasting Disease virus persists on the majority of the conventional breeding farms.     

A study of endemic viruses in a group of calves

An intensive study of 6 calves over a period of 14 months using viral isolation and serum neutralization techniques indicated that they were infected with a variety of enteroviruses and para-influenza 3 virus. Maternal antibody to infectious bovine rhinotracheitis and bovine viral diarrhoea viruses was present at one month. Active infection with these two viruses was not demonstrated during the course of the study.     

Serosurvey of five viruses in chickens on smallholdings in Bangladesh

A serologic survey was undertaken in chickens in smallholdings in Bangladesh for avian influenza A virus (AIV), egg drop syndrome '76 virus (EDS'76V), infectious bronchitis virus (IBV), Newcastle disease virus (NDV) and reovirus (RV) in three phases: January 2002-May 2003, September 2003-August 2004, and August 2005-March 2006. Four hundred thirty-six sera collected in the 2nd phase, 295 in the first phase, 755 in the 1st plus 2nd phases and 295 in the 1st phase were investigated for AIV, EDS'76V, IBV and RV, respectively, using enzyme linked immunosorbent assays. All 854 sera collected in the three phases were screened for NDV using hemagglutination inhibition test. In chickens 20% were seropositive to AIV, 3% to EDS'76V, 74% to IBV, 88% to NDV, and 47% to RV. The seroprevalence in flocks was 23% to AIV, 6% to EDS'76V, 79% to IBV, 89% to NDV and 56% to RV. Twenty-five percent chickens had > or = 10log(2)HI titers to NDV.     

Stimulation with a class A CpG oligonucleotide enhances resistance to infection with feline viruses from five different families

ABSTRACT: Domestic cats are commonly affected by viral pathogens that induce lengthy infections with fatal outcomes. Prevention of viral propagation is of primordial importance in shelters and catteries, where cats from different backgrounds have narrow contacts. Oligonucleotides (ODN) containing cytosine-phosphate-guanosine motifs of class A (CpG-A) are highly potent synthetic inducers of innate antiviral mechanisms. The aim of this study was to test their ability to modulate innate immune responses and prevent viral replication as stand-alone agents in the domestic cat. CpG-A stimulation of feline peripheral blood mononuclear cells (PBMCs) enhanced their proliferation, increased the presence of co-stimulatory molecules on their surface and influenced their gene expression profiles in an antiviral orientation. Incubation of the supernatants of CpG-A stimulated PBMCs with feline cell lines of epithelial and fibroblastic origin induced expression of the antiviral myxovirus resistance (Mx) gene in these target cells, which also showed enhanced resistance to feline viruses from five distinct families, namely Coronaviridae, Herpesviridae, Caliciviridae, Parvoviridae, and Retroviridae. Most importantly, subcutaneous administration of CpG-A in domestic cats systemically increased the expression of Mx, reaching maximal levels within 24 h. Plasma from treated cats could furthermore inhibit viral replication in vitro. Altogether, our data highlight the promising potential of CpG-A to induce a preventive antiviral state in the cat and to protect feline populations against a broad range of virus infections.     

Four-year study of lameness in piglets at a research station

Lameness in piglets up to nine weeks old was studied in a research station herd for four years; 9411 piglets were born alive, of which 9.8 per cent were treated for lameness. In litters born to gilts, 9.9 per cent of the piglets were treated for lameness, in litters born to sows of parity 3, 11.4 per cent of the piglets were treated, but in litters born to sows of parity 4 to 7 the proportion of piglets treated for lameness decreased to about 8 per cent. Around 75 per cent of all cases were observed in piglets less than three weeks old; the incidence risk of lameness decreased from 2.7 per cent during the first week of life to 0.3 per cent after weaning. The average weight of affected piglets was reduced by approximately 8 per cent at nine weeks of age. There was no overall association between lameness and sex or birth weight within sex. The mortality among lame gilts was higher at all ages than among healthy gilts, but among barrows a higher mortality was observed only during the late suckling period. Litters with 12 or more piglets had a higher incidence of lameness. Clinical signs of disease in the sow and whether the piglets were given an intramuscular injection of 200 mg of iron on their second, third or fourth day of life had no effect on the incidence of lameness.     

5种人兽共患病病毒多重RT-PCR检测方法的初步建立

为建立可同时检测裂谷热病毒(RVFV)、戊型肝炎病毒(HEV)、狂犬病毒(RV)、水泡性口炎病毒(VSV)及口蹄疫病毒(FMOV)5种人兽共患病病毒的多重RT-PCR快速检测方法,本研究根据GenBank登录的上述5种病毒的全基因组序列,设计了5对多重PCR引物,通过优化反应条件,建立检测以上5种病毒的多重RT-PCR方法.通过对同一种属的其他病毒及相关病毒的检测,确定方法的特异性;通过对体外转录合成的RNA进行定量检测的方法,确定方法的敏感度.实验结果表明:在同一RT-PCR反应体系中可同时检测以上5种病毒,扩增片段长度分别为499 bp、137 bp、274 bp、224 bp、389 bp;而对新城疫病毒(NDV)、赤羽病病毒(AKAV)、牛流行热病毒(BEFV)和乙型脑炎病毒(JBEV)的检测均为阴性;5种病毒RNA的最低检测拷贝数分别为2.91×104、3.14×1 03、1.25×103、6.65×103和2.38×104.利用该方法对11份RV已知阳性样本和7份HEV已知阳性样本检测结果均呈阳性.本研究建立了一种快速、可同时检测5种人兽共患病病毒的多重RT-PCR检测方法,该方法具有良好的特异性和较高的敏感性.     

Lack of pathogenicity of five serotype 2 infectious bursal disease viruses in chickens

The pathogenic potential of five strains of serotype 2 infectious bursal disease virus (IBDV) for specific-pathogen-free chickens was examined. There were no gross or microscopic lesions in the inoculated chickens. Bursa-to-body-weight ratios of IBDV-infected chickens were not significantly different from those of uninfected controls. Virus-neutralizing antibodies to IBDV of serotype 2, but not serotype 1, were detected in infected chickens. This study indicated that the serotype 2 viruses examined were infectious but not pathogenic in chickens.     

多重连接探针扩增对5种牛病毒同步检测方法的建立

现有的动物疫病诊断技术多是针对单一病原检测,而动物疫病的流行通常是多种病原混合感染,目前的诊断技术不能很好地满足国境口岸快速、高通量检疫的需求,一直以来多重检测技术的研究是动物疫情监测、疫病控制领域关注的焦点。本试验在前期猪病混合感染诊断研究基础上,进一步利用多重连接探针扩增(MLPA)技术,以蓝舌病病毒(BTV)、牛传染性鼻气管炎病毒(IBRV)、牛病毒性腹泻病毒(BVDV)、牛地方流行性白血病病毒(EBLV)和口蹄疫病毒(FMDV)为研究对象,分别设计这5种牛病毒的MLPA探针,将这5种探针混合,建立可以同时检测这5种病毒的MLPA扩增方法。特异性试验表明:每种病毒的探针都是特异的,只能识别各自的目的片段,不能扩增出其他相关病毒,探针之间也不存在交叉反应;敏感性试验结果表明:5重MLPA扩增的最低检测限可以达到单个病毒核酸的2 000个拷贝。经过对136份临床样品的检测,该方法与现有荧光PCR方法的符合率达到100%,能够正确地检测出每份阴、阳性样品及混合感染样品。本研究建立的5种病毒MLPA检测方法可以实现1次采样,1次分析,同时检测5种牛病毒的目的,该技术特异性强、敏感性高,加之其多重性检测的优势,有望成为未来疫病检测的新方向。     

Seroprevalence and genetic characteristics of five subtypes of influenza A viruses in the Chinese pig population: A pooled data analysis

A literature review and pooled data analysis were carried out to examine the prevalence of antibodies against five influenza virus subtypes in pigs in China over a 10-year period (1999–2009). The average seropositive frequencies of subtypes H1, H3, H5, H7 and H9 were 3478/11,168 (31.1%), 2900/10,139 (28.6%), 77/5945 (1.3%), 0/1440 (0%) and 86/3619 (2.4%), respectively. There was a geographical variation in the seroprevalence of subtype H1, with the highest seroprevalence in pigs in South and East China. BLAST analysis of genetic sequences revealed that genome segments with moderate homology to the 2009 pandemic influenza A (H1N1) virus were present among swine influenza viruses isolated in China, especially in South and East China. It was concluded from both serological and genetic studies that subtypes H1, H3, H5 and H9 are currently co-circulating in pigs in China, with the H1 subtype most commonly detected, followed by H3.     

5种冷季型草坪草的耐热性研究

通过生化培养箱模拟北京地区的高温高湿环境,对高羊茅（Festuca arundinacea）、多年生黑麦草(Lolium perenne)、匍匐剪股颖（Agrostis stolonifera）、草地早熟禾（Poa pratensis）和粗茎早熟禾(P.trivialis)这5种冷季型草坪草在热胁迫过程中的外观质量指标每株绿叶数、生长高度和生理生化指标叶片相对含水量、叶片相对电导率、叶绿素含量、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性进行分析。结果表明,在昼夜35 ℃/30 ℃的高温下,随着胁迫时间的延长,5种草坪草叶片相对含水量下降,叶片相对电导率上升。叶片叶绿素含量在高温环境中变化趋势不一致,高羊茅、多年生黑麦草、草地早熟禾的叶绿素含量呈先上升后下降的趋势,而匍匐剪股颖和粗茎早熟禾则呈现出持续下降的趋势。随着高温胁迫时间的延长,5种草坪草的SOD、POD活性呈先上升后下降的变化趋势。CAT活性下降,且随着时间的延长,POD和CAT活性下降的幅度增大。在高温胁迫过程中,5种草坪草每株绿叶数和植株生长高度降低。 通过聚类分析可将5种草坪草大致聚为3个耐热级别：1级（相对耐热）高羊茅;2级（中等耐热）草地早熟禾、多年生黑麦草、匍匐剪股颖;3级（相对敏感）粗茎早熟禾。     

5种脑炎人兽共患病病毒多重RT-PCR检测方法的建立

为建立同时检测流行性乙型脑炎病毒(JEV)、森林脑炎病毒(TBEV)、东方马脑炎病毒(EEEV)、西方马脑炎病毒(WEEV)和基孔肯雅病毒(CHIKV)5种人兽共患脑炎病病毒的多重RT-PCR方法,本研究根据GenBank登录的相关病毒基因序列设计特异引物,通过优化引物组合及PCR反应条件,建立可同时检测5种病毒的方法,扩增片段长度分别为411 bp(JEV)、945 bp(TBEV)、193 bp(EEEV)、545 bp(WEEV)和769 bp(CHIKV);该方法具有良好的特异性,对病毒核酸最低检测拷贝数分别为7.1×103、3.6×103、2.2×103、5.6×103和5.1×103.该方法具有特异性强、灵敏度高、操作简便等优点,为以上5种人兽共患脑炎病病毒提供快速检测手段.