Bovine herpesvirus type 1 abortions detected by a semi-nested PCR in Brazilian cattle herds

Bovine herpesvirus type 1 (BHV-1) was investigated by a semi-nested polymerase chain reaction (SN-PCR) and by MDBK cell culture virus isolation in organ fragments from 55 aborted fetuses collected from beef and dairy cattle herds with history of reproductive problems in the North of Paraná State, Brazil. A 425 bp amplicon of the BHV-1 glycoprotein D gene was detected in 14 (25.4%) aborted fetuses. BHV-1 was isolated in MDBK cells from the tissue of 5 (9.1%) fetuses. The specificity of positive results was evaluated by Restriction Fragment Length Polymorphism (RFLP) with Bgl I restriction of DNA amplified by SN-PCR, and by virus-neutralization and immunofluorescence with rabbit anti-BHV-1 polyclonal antibodies for virus isolated in cell culture. The results of this work demonstrate the importance of using other diagnostic techniques, like SN-PCR, for BHV-1 detection in organ fragments from aborted fetuses and the high frequency of this virus in reproductive failures in Brazilian cattle herds.     

一例犊牛呼吸道疾病的病原学诊断

[目的] 2023年8月,天津某牛场暴发以呼吸道症状为突出特征的传染病。为了确定病因,对发病犊牛进行相关病原的病原学诊断。[方法] 采集病死犊牛肺部病料,采用PCR方法对牛副流感病毒3型（BPIV-3）、牛呼吸道合胞体病毒（BRSV）、牛疱疹病毒1型（BHV-1）、牛腺病毒3型（BAdV-3）、牛分枝杆菌（Mycobacterium bovis）、牛肺炎克雷伯菌（Bovine Klebsiella pneumoniae）、牛支原体（Mycoplasma bovis）7 种牛呼吸道病原进行检测。[结果] 样本检测出BHV-1、BAdV-3共2 种病原,存在混合感染。其他病原未检出。[结论] 本研究证实BHV-1、BAdV-3在该牛场中存在和流行,为犊牛呼吸道疾病防控提供参考。     

Antibodies against bovine herpesvirus 4 are highly prevalent in wild African buffaloes throughout eastern and southern Africa

Bovine herpesvirus 4 (BoHV-4) has been isolated from cattle throughout the world. Interestingly, a survey of wild African buffaloes mainly from the Maasai Mara Game Reserve in Kenya revealed that 94% of the animals tested had anti-BoHV-4 antibodies [Rossiter, P.B., Gumm, I.D., Stagg, D.A., Conrad, P.A., Mukolwe, S., Davies, F.G., White, H., 1989. Isolation of bovine herpesvirus-3 from African buffaloes (Syncerus caffer). Res. Vet. Sci. 46, 337–343]. These authors also proposed that the serological antigenic relationship existing between BoHV-4 and alcelaphine herpesvirus 1 (AlHV-1) could confer to BoHV-4 infected buffaloes a protective immune response against lethal AlHV-1 infection. In the present study, we addressed two questions related to Rossiter et al. paper. Firstly, to investigate the role of the African buffalo as a natural host species of BoHV-4, the seroprevalence of anti-BoHV-4 antibodies was analysed in wild African buffaloes throughout eastern and southern Africa. A total of 400 sera was analysed using two complementary immunofluorescent assays. These analyses revealed that independently of their geographical origin, wild African buffaloes exhibit a seroprevalence of anti-BoHV-4 antibodies higher than 68%. This result is by far above the seroprevalence generally observed in cattle. Our data are discussed in the light of our recent phylogenetic study demonstrating that the BoHV-4 Bo17 gene has been acquired from a recent ancestor of the African buffalo. Secondly, we investigated the humoral antigenic relationship existing between BoHV-4 and AlHV-1. Our results demonstrate that among the antigens expressed in AlHV-1 infected cells, epitope(s) recognised by anti-BoHV-4 antibodies are exclusively nuclear, suggesting that the putative property of BoHV-4 to confer an immune protection against AlHV-1 relies on a cellular rather than on a humoral immune response.     

上海市某马场马疱疹病毒1型感染的确诊

采用马疱疹病毒1型和4型二重PCR分型方法,对上海市某马场临床疑似病例的鼻拭子和血浆样品进行检测,同时对扩增产物进行测序和比对,确诊为马疱疹病毒1型阳性,表明上海市马群中存在马疱疹病毒1型感染。因此,应提高上海市马匹饲养管理水平,加强马疱疹病毒1型的定期免疫和检疫,及时对阳性马匹进行隔离,对马厩进行消毒。     

Molecular characterization of a Korean bovine parainfluenza virus type 3 isolate

Bovine parainfluenza virus type 3 (BPIV-3) was isolated from Korean native cattle that presented clinical signs of mild pneumonia. The complete genome of a representative isolate (12Q061) was sequenced. The newly identified strain, which was found to be distinct from the previously reported genotypes A (BPIV-3a) and B (BPIV-3b) and closely related to the Chinese strain SD0835, was tentatively classified as genotype C (BPIV-3c). Our results suggest a relationship between BPIV-3 genetic variation and the geographic location of its isolation. Identification of these new BPIV-3 genotypes may facilitate the development of improved diagnostic methods and vaccines. This is to our knowledge the first report of the identification and molecular characterization of BPIV-3 in Korea.     

牛疱疹病毒1型主要囊膜糖蛋白研究进展

牛疱疹病毒(BHV-1)属于α疱疹病毒亚科的DNA病毒,可引起牛高热、上呼吸道感染和母牛流产。该病毒能在牛的感觉神经节内建立潜伏感染,因此,对于该病毒感染的预防和治疗较为困难。BHV-1除了引起初始感染外,还可通过免疫抑制引起动物继发感染,导致动物死亡。研究发现,病毒入侵牛机体时,病毒囊膜糖蛋白在病毒与细胞间相互作用的过程中发挥了重要作用。论文对牛疱疹病毒1型主要囊膜糖蛋白(包括gB、gD、gN)的结构特征和生物学特征加以归纳总结,为该病毒的感染特性研究和预防提供参考。     

Attenuation of a virulent type 2 bovine viral diarrhea virus

The purpose of this study was to produce an attenuated bovine viral diarrhea virus (BVDV) type 2 strain as a tool for identifying potential virulence markers in the BVDV2 genome. The attenuation of the virulent strain, BVDV2-24515, was accomplished by in vivo and in vitro passage. The strain was initially used to infect an elk (Cervus elaphus) [J. Wildl. Dis. 35 (1999) 671], re-isolated at 7 days post-inoculation from serum, and then subsequently passaged 56 times in cell culture. Two groups of calves were inoculated intranasally with either BVDV2-24515 or the putative attenuated virus, designated BVDV2-LATT. Calves inoculated with BVDV2-24515 had cumulative clinical scores which ranged from 6 to 53. Clinical signs in these calves consisted of anorexia, depression, dehydration, diarrhea (±bloody), and pneumonia. Several calves developed leukocytopenia, primarily a neutrocytopenia, and presented lesions of enteritis or pneumonia at necropsy. In contrast, cattle inoculated with BVDV2-LATT had cumulative clinical scores which ranged from 0 to 2. This was not significantly different from that of controls which received no virus (range: 0–1). Calves inoculated with BVDV2-LATT produced high neutralizing antibody titers against BVDV2. Thus, in addition to its potential use as a tool for identifying virulence markers, the attenuated virus is also worthy of further study as a candidate virus for inclusion in a modified-live vaccine.     

牛呼吸疾病综合征及其防治

牛呼吸疾病综合征是严重危害国内外肉牛养殖业的一种重要传染病,该病的致病因素复杂,包括支原体、病毒和细菌等特异性病原以及运输应激等多种因素。美国等发达国家对该病的攻关研究开始于上世纪80年代初,其研究和临床防控均已达到较高水平,但仍认为该病将是未来10～20年养牛业所面临的主要疾病。我国对该病的认识和研究尚处于起步阶段,借鉴世界上发达国家的先进经验将有助于提升我国对该病的防控水平。     

牛疱疹病毒gD-PCR鉴别检测方法的建立

建立一种PCR技术,既能快速检测疱疹病毒1型成员牛传染性鼻气管炎病毒(bovine infectious rhinotracheitisvirus,IBRV),又能区分牛疱疹病毒5型和伪狂犬病毒。根据基因库中牛传染性鼻气管炎病毒的gD基因序列,应用primer 5.0软件设计了gD PCR引物,建立PCR方法,反应条件是:94℃预变性5min,94℃1min,58℃1min,72℃1min,30个循环,72℃7min,4℃5min。该方法能从IBRV阳性样本和参考毒株中扩增出372bp的目的片段,而从同属的牛疱疹病毒5型中扩增出440bp和206bp两条目的片段,从同属的伪狂犬病毒中扩增出303bp的目的片段,但不能从非疱疹病毒属成员猪呼吸与繁殖综合征病毒中扩增出目的条带。该PCR检测IBRV的灵敏度可达1PFU/mL以上。鉴于其灵敏度高、特异性好,可望在牛疱疹病毒感染快速鉴别检测方面发挥重要作用。     

Herd and individual animal risks associated with bovine tuberculosis skin test positivity in cattle in herds in south west England

The aim of this study was to investigate the cattle—exposure factors associated with the risk of a bovine animal reacting to a bovine tuberculosis (bTB) skin test at a whole herd test. There were 148 study farms enrolled. These were located in six counties of the south west of England in an area considered endemic for bovine tuberculosis (bTB): 24% were restocked after foot and mouth disease (FMD) in 2001; all farms were located within the Randomised Badger Culling Trial (RBCT) area. Data on cattle on these farms were sourced from the bTB Vetnet database from 1996 to 2004 and from the British Cattle Movement Scheme database. Individual animal records were created that included data on whether or not an animal became a reactor at a full-herd bTB test between 1 June 2001 and 19 August 2004, their prior exposure to cattle with bTB (defined by presence at a bTB test where at least one reactor was detected), whether the animal was homebred, the farm history of bTB and the farm restocking status. Data from 144 farms were used, 4 farms had no data.Cattle were more likely to react to the bTB skin test when they had been present at a previous bTB herd test (or tests) where other cattle had reacted to the skin test. This positively correlated with age and the number of bTB tests an animal had had. Cattle on restocked farms were less likely to react to the skin test compared with cattle on continuously stocked farms. These results highlight the likely importance of exposure to infected cattle at a previous test as a source of infection to cattle that subsequently became reactors and suggest that there was a lower risk of exposure to bTB to cattle in newly formed herds.     

Bovine herpesvirus 5 BICP0 complements the bovine herpesvirus 1 homolog

Bovine herpesvirus 1 (BoHV-1) and BoHV-5 are closely related (82% amino acid identity) but differ strongly in neuropathogenesis. The immediate-early gene for BICP0 is less conserved (70% amino acid identity) and may contribute to a dissimilar phenotype. A peculiar difference is a guanosine hexamer in the BICP0-1 gene which aligns with only five guanosines in the BICP0-5 gene and therefore results in a frameshift in the latter open reading frame. Thus, the C-terminal amino acid sequence (residues 643–676 of BICP0-1 vs. 655–720 of BICP0-5) is completely different. We introduced the BICP0-5 frameshift into the BoHV-1 genome cloned as a bacterial artificial chromosome (BoHV-1 BAC) using the Red recombination system with galK selection and counterselection. Transfection of MDBK cells with the resulting BAC produced recombinant virus that replicated like wild type BoHV-1 in vitro. Attempts to exchange the entire BICP0-1 gene by the BoHV-5 homolog using the same approach failed repeatedly. Therefore, we cotransfected purified BICP0⁻/galK⁺-BoHV-1 BAC DNA with a recombination plasmid coding for BICP0-5 with or without a HA tag into MDBK cells. BoHV-1 recombinants expressing the respective proteins were characterized. In vitro, all recombinants grew to similar titers as the parental viruses, which demonstrates that BICP0-5 compensates for the growth defect of BICP0⁻/galK⁺-BoHV-1 and functionally complements BICP0-1 of BoHV-1. We conclude that BICP0 may be suitable to positively select BoHV-1 recombinants with deletions or insertions of additional genes of interest.