潜根线虫对稻苗根系侵染的影响

盆栽接种试验表明,在水稻胚芽期潜根线虫（Hirschmanniella spp.）可以侵染胚及幼根,但不侵染幼芽;对种子萌发和成苗率无明显影响。潜根线虫在土壤介质中对水稻根系的侵入量显著大于在水、沙介质中的水稻根系侵入量。在土壤营养丰富的条件下,低密度的潜根线虫量侵染能刺激水稻苗须根产生,但在中、高接种量下明显抑制了须根量的产生。     

新城疫疫苗预防鸭副粘病毒病效果

为探讨新城疫疫苗对鸭副粘病毒病的预防效果,应用鸡新城疫活疫苗(I系和Lasota株)免疫2日龄雏番鸭,分别于免疫后7 d攻毒,并采血测定HI抗体。结果显示鸡新城疫I系活疫苗和Lasota疫苗对番鸭均安全,单独或混合应用均能有效抵抗鸭副粘病毒和新城疫标准毒(F48E8)的攻击;同时番鸭免疫后7 d I系疫苗诱导的HI抗体水平显明高于Lasota疫苗,而攻毒后35 d的HI抗体水平则以Lasota疫苗组高于I系疫苗组。上述结果表明新城疫I系和Lasota疫苗均可用于预防鸭副粘病毒病。     

疱疹病毒对新生幼犬的危害

从病原学、流行病学、发病症状、临床病理、诊断等方面论述了疱疹病毒对新生幼犬的严重危害,早期感染可致败血症,死亡率在头三周达75%。采取有效的预防措施和治疗方法后,大大降低死亡率。     

新疆牛巴贝斯虫病的流行病学调查

[目的]2006～2008年对全疆14个地州的牛巴贝斯虫病进行流行病学调查.[方法]使用已建立的牛巴贝斯虫病间接ELISA检测方法,以纯化的重组蛋白GST - MSA -2作为抗原.[结果](1)新疆存在着牛巴贝斯虫病.在2006年采集的278份牛血清样品中,阳性血清7份,感染率为2.52;.在2007年的532份牛血清样品中检出阳性血清32份,感染率为3.13;.在2008年的530份牛血清中检出阳性血清43份,感染率为5.28;.(2)2008年在地方流行性疫病区牛巴贝斯虫感染率高达28;.(3)牛巴贝斯虫病所在的地州由2006年的5个扩大到2008年的11个.[结论]新疆牛巴贝斯虫病的感染率逐年上升,疫区面积不断扩大,流行区内感染率激增,牛巴贝斯虫病的防治不容忽视.这是新疆首次利用血清学方法对全疆牛巴贝斯虫病进行大规模的流行病学调查.     

First detection of porcine norovirus GII.18 in Latin America

Human (Hu) noroviruses (NoVs) circulate worldwide infecting people of all ages in developing and developed countries. Animal NoVs present some antigenic and genetic relationship to HuNoVs, although their zoonotic potential has not been established yet. Among animal NoVs, porcine (Po) NoVs are the most genetically related to HuNoVs. PoNoVs have only been detected in healthy finisher pigs in a few developed countries. Information about them lacks in developing countries. In this study 96 fecal samples from pigs of different ages from five farms in Rio de Janeiro State, Brazil were tested for NoVs. We report detection and genotyping by RT-PCR, nucleotide sequencing and phylogenetic analysis of partial polymerase and capsid regions of viral genome PoNoV genogroup II genotype 18 (GII.18) in one stool sample from a healthy finisher pig. This is the first report of PoNoV detection in Latin America and it supports the assumption that PoNoVs present a worldwide distribution.     

The relationship between cellular immune response to foot-and-mouth disease virus Asia 1 and viral persistence in Indian cattle (Bosindicus)

Foot-and-mouth disease (FMD), the most contagious animal disease, is associated with persistent viral infection in ruminants, despite the induction of systemic immune response. The present study was performed to decipher the relation between the persistent FMD virus (FMDV) infection and cellular immune response in Indian cattle (Bosindicus) following experimental inoculation of FMDV Asia 1. Persistent viral infection (carriers) was detected by antigen capture RT-PCR on the oesophageal-pharyngeal fluid. Viral excretion was found to be intermittent and strongly variable among the persistently infected Indian cattle. Lymphocyte proliferative (LP) response, assessed as reactivity of peripheral blood mononuclear cells to FMDV Asia 1 antigen (Ag) was of low magnitude indicating a weak primary cellular immune response following infection. LP response to FMDV Ag was higher among the non-carriers than carriers of FMDV Asia 1. An enhanced LP response was associated with the lack of virus shedding in the OPF. The findings of this study are suggestive of relationship between cellular immune response and virus excretion during persistence of FMDV Asia 1 in infected cattle.     

柞蚕对ApNPV感染的抵抗性与部分生命力性状的相关性

柞蚕核型多角体病毒(ApNPV)是危害柞蚕的主要病原。以柞蚕部分现行品种、杂交种及引进品种为材料,研究柞蚕对ApNPV感染的抵抗性与部分生命力性状的相关性。结果显示,稚蚕对ApNPV感染的抵抗性与普通孵化率呈显著正相关,相关系数为0.71,而与5龄壮蚕对ApNPV感染的抵抗性及自然发病率无显著相关关系;5龄壮蚕对ApNPV感染的抵抗性与5龄壮蚕感染ApNPV后的虫蛹统一生命率呈显著正相关,相关系数为0.98。研究结果表明,柞蚕品种的抗ApNPV病毒性能应依据稚蚕期和5龄壮蚕期2个发育阶段对病毒感染的抵抗性进行综合鉴定。     

家蚕质型多角体病毒感染应答的假定蛋白基因全长cDNA克隆与表达特征分析

在感染家蚕质型多角体病毒(BmCPV)的家蚕中肠组织中发现一个差异表达的假定蛋白基因。利用cDNA末端快速扩增(RACE)技术克隆了该假定蛋白基因的全长cDNA。用生物信息学方法进行基因序列与结构分析表明:该基因全长cDNA序列为486bp,包含108bp的5′端非翻译区序列(5′-UTR)和153bp的3′端非翻译区序列(3′-UTR),开放阅读框(ORF)为225bp,编码74个氨基酸,蛋白分子质量为6.888kD,等电点为5.27;该基因由3个外显子和2个内含子组成,ORF位于第2外显子内,编码蛋白含二次跨膜结构,多肽链表现为疏水性,在多肽链上的第15～16氨基酸残基可能是信号肽的切割位点。RT-PCR结果显示该基因在家蚕5龄幼虫的丝腺、血液、脂肪体、生殖腺及中肠组织中均有表达;荧光定量PCR结果表明该基因在感染Bm-CPV的家蚕中肠组织中的表达水平为正常家蚕中肠组织的6.28倍。研究结果为进一步解析该基因的功能奠定了基础。     

Risk factors for methicillin-resistant Staphylococcus aureus (MRSA) infection in dogs and cats: a case-control study

Risk factors for methicillin-resistant Staphylococcus aureus (MRSA) infection in dogs and cats were investigated in an unmatched case-control study. A total of 197 animals from 150 veterinary practices across the United Kingdom was enrolled, including 105 MRSA cases and 92 controls with methicillin-susceptible S. aureus (MSSA) infection. The association of owners and veterinarian staff with the human healthcare sector (HCS) and animal-related characteristics such as signalment, antimicrobial and immunosuppressive therapy, and surgery were evaluated as putative risk factors using logistic regression. We found that significant risk factors for MRSA infection were the number of antimicrobial courses (p = 0.005), number of days admitted to veterinary clinics (p = 0.003) and having received surgical implants (p = 0.001). In addition, the odds of contact with humans which had been ill and admitted to hospital (p = 0.062) were higher in MRSA infected pets than in MSSA controls. The risk factors identified in this study highlight the need to increase vigilance towards identification of companion animal groups at risk and to advocate responsible and judicious use of antimicrobials in small animal practice.     

Modelling the dynamics of intramammary E. coli infections in dairy cows: understanding mechanisms that distinguish transient from persistent infections

The majority of intramammary infections with Escherichia coli in dairy cows result in transient infections with duration of about 10 days or less, although more persistent infections (2 months or longer) have been identified. We apply a mathematical model to explore the role of an intracellular mammary epithelial cell reservoir in the dynamics of infection. We included biological knowledge of the bovine immune response and known characteristics of the bacterial population in both transient and persistent infections. The results indicate that varying the survival duration of the intracellular reservoir reproduces the data for both transient and persistent infections. Survival in an intracellular reservoir is the most likely mechanism that ensures persistence of E. coli infections in mammary glands. Knowledge of the pathogenesis of persistent infections is essential to develop preventive and treatment programmes for these important infections in dairy cows.