Properties of a respiratory syncytial virus isolated from a sheep with rhinitis

A virus isolated from a yearling cross-bred ewe was identified as respiratory syncytial virus (RSV) by indirect immunofluorescence and by virus neutralization with bovine RSV antisera. The virus caused a mild conjunctivitis in 3-month-old lambs when inoculated alone. Although clinical signs of pneumonia were not observed, there was gross and microscopic evidence of pulmonary inflammation in the lungs of lambs inoculated with either the sheep RSV isolate alone or in conjunction with Pasteurella haemolytica. Lung lesions in the dual infection were more severe, with approximately 10% of the total lung mass affected. Lavage fluids from lambs inoculated with virus and bacteria contained approximately 3 times more inflammatory cells than from control lambs or lambs inoculated with virus only. The sheep RSV isolate was classified as a mild respiratory pathogen in lambs of this age. Speculations on the potential importance of this virus in interspecies transmission to cattle and goats were discussed.     

Characterization of a parvovirus isolated from the diarrheic feces of a pig

A small DNA virus was isolated from the feces of a sow with diarrhea and identified as a parvovirus on the basis of its properties. The virus replicated preferentially in cell cultures of swine origin, including primary porcine thyroid gland and kidney cell cultures in which the cytopathic effect developed. The virus agglutinated erythrocytes of guinea pig, mouse and human group O but not these of chicken. The growth of the virus was inhibited by 5-iodo-2'-deoxyuridine. The virus was resistant to ether and heating at 56 degrees C for 30 min and stable at pH 3.0. The buoyant density of the infectious particles was 1.40 g/ml in CsCl density gradient, and the virions were 27 nm in diameter by electron microscopy. The viral protein seemed to be separated into four polypeptides with molecular weights of 81k, 70k, 66k and 62k daltons respectively. Cross serum neutralization test demonstrated that the virus was antigenically different from porcine parvovirus as well as bovine and canine parvoviruses. These findings and the survey on neutralizing antibody distribution indicated indirectly that another parvovirus which could be antigenically distinguished from well-known porcine parvovirus had been widespread among swine in Japan.     

Isolation of a paramyxovirus from the cerebrospinal fluid of a dog with posterior paresis

A paramyxovirus was isolated from cerebrospinal fluid of a dog with a history of incoordination and posterior paresis. The virus apparently was not related to canine distemper virus (CDV), considering the lack of virus neutralization with CDV-specific antibody, negative immunofluorescence with CDV-specific conjugate, and avirulence for ferrets. The virus was antigenically related to a prototype strain of canine parainfluenza virus, as determined by positive immunofluorescence with canine parainfluenza virus-specific conjugate and virus neutralization tests.     

Multicentric fibrosarcoma in a cat and a review of the literature

A case of multicentric fibrosarcoma in a ten month old domestic short-haired cat is presented and discussed. Tumor tissue was found to involve the right distal forepaw, right shoulder area and a popliteal lymph node. This anaplastic neoplasm was concentrated primarily in subcutaneous tissues but also extended to muscle, bone and lung. The cat was found to be positive for feline leukemia virus by the ELISA test. Based on these findings, it is likely that the lesions in this case result from an interaction between the feline leukemia virus and feline sarcoma virus.     

Characterization of a parainfluenza virus isolated from a bottlenose dolphin (Tursiops truncatus)

A novel member of the parainfluenza virus family was identified in a bottlenose dolphin with respiratory disease. The case animal was a 19-year old male Atlantic bottlenose dolphin (Tursiops truncatus) that presented with signs of respiratory illness, including raspy, foul-odored breaths and cream-colored exudate from the blowhole. Focally extensive pyogranulomatous bronchointerstitial pneumonia with moderate numbers of intralesional yeast organisms was identified on histopathological examination. Other significant microscopic findings included multifocal erosive and ulcerative tracheitis and laryngitis consisting of active laryngeal lymphatic tissue and dilated glands with eosinophilic fluid. The cause of death was attributed to respiratory disease of unknown etiology. In addition to the postmortem isolation of Candida glabrata and mixed bacteria from lung tissue, a virus was isolated from two antemortem affected lung aspirates collected over a 2-month period and two postmortem samples (mediastinal lymph node and left lung tissue homogenate). The morphology of the virions on negative staining and transmission electron microscopy was consistent with that of paramyxoviruses. Two genomic fragments, comprising 532 and 419 nucleotides from the open reading frames that code for the viral polymerase and fusion protein, respectively, were amplified by polymerase chain reaction using degenerate primers. Phylogenetic analyses of the two viral RNA segments showed that the isolate comprised a novel virus strain, tentatively named T. truncatus parainfluenza virus type 1 (TtPIV-1). The virus is monophyletic with, but genetically distinct from, the various bovine parainfluenza virus type 3 strains.     

牛病毒性腹泻病毒BVDV-JL株的分离与鉴定

本研究从吉林某牛场表现严重腹泻症状濒死牛的胸腺病料样品中分离一株病毒,该病毒在MDBK细胞中盲传4代无细胞病变产生,而通过RT-PCR和间接免疫荧光试验、微量血清中和试验检测表明该分离病毒株为牛病毒性腹泻病毒(BVDV),并命名为BVDV-JL.将BVDV-JL株F4代细胞培养液(10<'7.13>TCID<,50>/...     

Simulation study to assess the efficiency of a test-and-cull scheme to control the spread of the bovine viral-diarrhoea virus in a dairy herd

To control the spread of bovine viral-diarrhoea virus (BVDV), test-and-cull schemes have been used in Scandinavian countries, with success, when combined with strict control of new animal introductions into herds. In situations where BVDV reintroduction is likely to occur, it is necessary to assess precisely the expected efficiency of test-and-cull schemes. The objective of this study was to compare, by simulation, the persistence and consequences of BVDV infection in a fully susceptible dairy herd with either a test-and-cull scheme or no control action. We used a stochastic individual-based model representing the herd structure as groups of animals, herd dynamics, the contact structure within the herd and virus transmission. After an initial introduction of the virus into a fully susceptible herd, the frequency of purchases of animals that introduced the virus was simulated as high, intermediate or null. Virus persistence and epidemic size (total number of animals infected) were simulated over 10 years. The test-and-cull reduced the epidemic size and the number of days the virus was present except in herds with complete prevention of contact between groups of animals. Where no virus was reintroduced, virus persistence did not exceed 6 years with a test-and-cull scheme, whereas the virus was still present 10 years after the virus introduction in some replications with no control action (<2%). Where frequent purchases were made that led to virus introduction (6 within 10 years), with an intermediate virus transmission between groups, the probability of virus persistence 10 years after the first virus introduction fell from 31% to 8% with the test-and-cull scheme (compared to the do-nothing strategy). Within the newly infected herd, the test-and-cull scheme had no effect, on inspection, on the number of PI births, embryonic deaths or abortions over 10 years. Given this, the economic efficiency of the test-and-cull scheme should be further investigated.     

Foot-and-mouth disease virus: a long known virus, but a current threat

Foot-and-mouth disease virus (FMDV) was the first animal virus identified. Since then, FMDV has become a model system in animal virology and a considerable amount of information on its structure, biology and vaccinology has been obtained. However, the disease that this virus produces (FMD) still constitutes one of the main animal health concerns. In this review, we have attempted to summarise the state of the knowledge in different basic and applied areas of FMDV research, with emphasis on those aspects relevant to the control of the disease.     

Spread of bovine syncytial virus in a dairy herd over a two year period

During a two year period the spread of bovine syncytial virus was monitored in a closed herd of 50 to 100 milking cows. Out of a nucleus of 49 nonpregnant and pregnant heifers, six were found to be infected with bovine syncytial virus. Virus was detected only in the progeny of infected cows and not in the progeny of uninfected animals. Nineteen progeny of the bovine syncytial virus infected cows were studied in detail and virus was isolated from only four. Horizontal spread of the virus did not occur.     

The isolation and characterization of a strain of infectious bovine rhinotracheitis virus from stillbirth in swine.

A virus, designated 5089, which was isolated from tissue samples from two stillborn pig fetuses was identified on the basis of its morphology, cytopathology, physiocochemical and serological characteristics as a strain of infectious bovine rhinotracheitis (IBR) virus. Three piglets inoculated intranasally with 5089 virus did not respond serologically and no virus was isolated from their tissues at intervals after inoculation. They showed neither clinical signs nor significant lesions. A colostrum deprived calf which was inoculated intranasally with the same virus developed clinical signs typical of the respiratory form of IBR and the virus was reisolated on several occasions from nasal swabs.     

Evaluation of a protease activation mutant of Sendai virus as a potent live vaccine.

A protease activation mutant of Sendai virus, TR-5, was investigated as a candidate for a live vaccine. Vaccination with TR-5 which had been activated by chymotrypsin beforehand (active TR-5) elicited protective immunity against otherwise lethal challenge infection with wild-type Sendai virus in DBA/2, C3H and ICR strains of mice. Less of the active TR-5 was required to confer protection on mice compared with an ordinary ether-inactivated Sendai virus vaccine (split vaccine). The protective immunity elicited by TR-5 lasted longer and the booster effect was more prominent compared to the split vaccine. No seroconversion was observed with contact mice when housed in a cage with mice vaccinated with the active TR-5. The overall results show that the active TR-5 is an effective and safe live vaccine of Sendai virus in mice.     

大熊猫肝脏分离病毒部分特性的研究

电镜观察磷钨酸负染的大熊猫肝脏分离病毒细胞培养物,发现冠状病毒样粒子.细胞培养物超薄切片上可见细胞浆内病毒包涵体.理化学和生物学特性研究结果表明,病毒对氯仿、乙醚敏感,可耐受1 %胰蛋白酶的作用,具有一定的耐酸性和耐热性;病毒对FCWF细胞敏感,对Vero细胞不敏感,无血凝性和血吸附特性.采用犬冠状病毒阳性血清,经中和试验确定该分离病毒是一株犬冠状病毒,命名为CCV DXMV.以犬冠状病毒特异性PCR引物,可以从大熊猫肝脏组织和不同代次的病毒细胞培养物中,扩增出目的核苷酸片断.序列分析结果表明,该株病毒部分纤突蛋白基因序列与分离自美国的CCV NVSL株相应基因序列的同源性高达100 %.     

Isolation of a herpesvirus from the cell culture of a malignant melanoma of a ground squirrel (Spermophilus tridecemlineatus).

A subcutaneous neoplastic mass in a 13-lined ground squirrel which metastasized to regional lymph nodes and lung was studied. Histopathologically, the tumor architecture and cellular morphology were compatible with that of a malignant amelanotic melanoma. Ultrastructurally, the neoplastic tissue was composed of oval cells, spindle-shaped cells, and spindle-shaped cells with electron-dense cytoplasmic granules. Virus particles were not seen in these cells. Cell cultures from neoplastic tissue grew in complete monolayers and on initial passages contained a few herpesvirus particles. Secondary monolayer cell culture, when exposed to 5-iodo-2'-deoxyuridine or made into several serial subculture passages, caused the appearance of cytopathic effect and the demonstration of many virus particles. The ground squirrel agent, because it contained DNA, was sensitive to chloroform treated and had herpesvirus characteristics on electron microscopy, was considered a herpesvirus. The buoyant density of the virus was 1.298 g/cm3 and the diameter of the enveloped virus particles was 146 nm. This ground squirrel herpesvirus was antigenically distinct from other known herpesviruses.     

某规模化猪场伪狂犬病抗体检测与分析

目的:为了掌握规模化猪场伪狂犬病野毒感染情况,减少伪狂犬病所造成的经济损失,以及规模化猪场应当采取的有效防疫措施。方法:采用ELISA法对某规模化猪场7~12月份的经产母猪和后备猪进行伪狂犬病抗体检测。结果:该猪场的伪狂犬病阳性率为21.26%,是伪狂犬病野毒阳性场。结论:该猪场在检测出伪狂犬病抗体呈阳性后,采取了一系列措施,从而控制了疫情的发生。     

Ability of a mutagenized virus variant to protect young lambs from Rift Valley fever

A live attenuated vaccine virus variant of Rift Valley fever (RVF) virus was developed by passaging a human isolate in tissue culture under the influence of the mutagen 5-fluorouracil. This virus variant (MV P12) has been assessed in this study as to its suitability as a vaccine, by testing its pathogenicity in young lambs and measuring its ability to induce a protective immune response. Even high doses of the vaccine virus failed to induce any of the clinical or histopathologic changes associated with classical RVF virus infection. Although the vaccine induced mild pyrexia when given in high doses, viremia was not induced. Neutralizing antibody and a protective immune response was elicited with even low doses of vaccine virus. These data, along with data of other workers on the lack of abortigenicity of this virus variant, indicate that the MV P12 variant of RVF virus is an excellent candidate for a safe and effective vaccine against RVF.     

Vulvovaginitis of goats due to a herpesvirus

Two concurrent outbreaks of genital disease in goats were associated with infection by a herpesvirus that was isolated from vulval and vaginal lesions of affected does. Serum neutralising antibody to the virus was present both in goats with the clinical disease and some unaffected goats. Of 19 goat herds examined only 4 had serum neutralising antibody positive goats with low (5%) to high (60%) incidence of infection. The virus isolate was characterised as a herpesvirus on its physico-chemical and morphological features. It contained DNA and was inactivated at low pH and by treatment with lipid solvents and trypsin. The virus particles were icosahedral, consisting of a nucleocapsid surrounded by an envelope membrane and measured approximately 150 nm in diameter. The virus was serologically related to a New Zealand isolate of caprine herpesvirus (NZ-CpHV), associated with similar genital disease, and was distinct from bovine herpes virus-1 (BHV-1) showing a one way neutralisation pattern.     

Isolation of a European bat lyssavirus type 2 from a Daubenton's bat in the United Kingdom

European bat lyssavirus type 2 (EBLV-2) has been isolated once previously from a bat in the UK in June 1996. In September 2002, a Daubenton's bat (Myotis daubentonii) found in Lancashire developed abnormal behaviour, including unprovoked aggression, while it was in captivity. Brain samples from the bat were tested for virus of the Lyssavirus genus, which includes EBLV-2 (genotype 6), and classical rabies virus (genotype 1). A positive fluorescent antibody test confirmed that it was infected with a lyssavirus, and PCR and genomic sequencing identified the virus as an EBLV-2a. Phylogenetic comparisons with all the published sequences from genotype 6 showed that it was closely related to the previous isolate of EBLV-2 in the UK and suggested links to isolates from bats in The Netherlands. The isolation of EBLV-2 from a bat found on the west coast of England provides evidence that this virus may be present within the UK Daubenton's bat population at a low prevalence level.     

Hyena disease in cattle: a review

Hyena disease was first reported in France in 1975 and since then has been recognized in many countries. It is currently regarded as a disorder of skeletal development, mainly localised in the pelvic limbs of young cattle. Some investigators consider that it is a metabolic disease but the authors believe that it may be caused by a virus. Their hypothesis, according to which bovine virus diarrhoea-mucosal disease virus is involved, is based on epidemiological, histopathological and immunological evidence.