An epizootic of respiratory syncytial virus infection in a dairy herd

Respiratory syncytial virus was the cause of a severe epizootic of bovine respiratory tract disease. The virus, isolated from a sick cow during the epizootic, produced cytopathic effect in a bovine turbinate cell line 14 days after it was inoculated. Additional support for the diagnosis came from the results of pathologic and serologic examinations. Lesions consistently present were severe necrotizing bronchiolitis and epithelial syncytia projecting from bronchiolar and alveolar walls. Also, in the cow from which the virus was isolated, there was tracheitis with a syncytial-like change involving the mucosal epithelium.     

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.     

Sendai virus, the mouse parainfluenza type 1: a longstanding pathogen that remains up-to-date

Biologically speaking, Sendai virus (SeV), the murine parainfluenza virus type 1, is perceived as a common respiratory pathogen that is endemic in many rodent colonies throughout the world. Currently it is believed that SeV is the leading cause of pneumonia in mice and together with the mouse hepatitis viruses, is the most prevalent and important of the naturally occurring infections of mice. The scientific community also considers SeV as the archetype organism of the Paramyxoviridae family because most of the basic biochemical, molecular and biologic properties of the whole family were derived from its own characteristics. Recently, scientific interest for this old pathogen has re-emerged, this time because of its potential value as a vector for gene transfer. This review aimed at drawing an exhaustive picture of this multifaceted pathogen.     

Immunosuppression in goats inoculated with parainfluenza type 3 virus

The humoral and cellular immune responses of goats experimentally infected with an ovine isolate of parainfluenza type 3 virus (PI-3) were examined. Virus neutralization and enzyme-linked immunosorbent assays were used to determine antibody in the serum and CSF. Lymphocyte stimulation, measured by [3H]thymidine incorporation into peripheral blood leukocytes, was used to determine cellular responses to phytomitogens and virus. There were significant suppression of peripheral blood leukocyte responses to T-cell mitogens early in the course of infection and delayed onset of virus-specific cell-mediated immunity. Delay in antibody formation did not occur. The suppression of mitogen response has been reported with other paramyxovirus infections. The importance of the suppressed cellular immune response for potentiating other infective agents is discussed.     

Studies on the pathogenesis of a Chinese strain of bovine parainfluenza virus type 3 infection in Balb/c mice

To date, three genotypes A, B, and C of bovine parainfluenza virus type 3 (BPIV3) have been isolated from cattle and only limited studies on the pathogenesis of the genotype A of BPIV3 infection in calves and laboratory animals have been conducted. The pathogenesis of the genotypes B and C of BPIV3 infection in calves and laboratory animals have not been reported. To alleviate the difficulties associated with sourcing suitable calves for infection studies, the establishment of BPIV3 infection model using laboratory model animals could aid in increasing the knowledge of the pathogenesis of this virus. Therefore thirty Balb/c mice were intranasally inoculated with a Chinese BPIV3 strain SD0835 which was classified as genotype C. Virus replications in mice were demonstrated by using virus isolation and titration, immunofluorescent staining, and immunohistochemistry and had occurred in the respiratory tissues as early as 24h after intranasal inoculation. The results of immunofluorescent staining and IHC implicated that the lungs and tracheas might be the major tissues in which the SD0835 infected and replicated. The histopathologic examinations revealed that alveoli septa thickening and focal cellulose pneumonia were seen in the lungs of experimentally infected mice. The aforementioned results indicated that the SD0835 of the genotype C was pathogenic to Balb/c mice and the mouse infection model could cast light on the genotype C of BPIV3 infection process and pathogenesis.     

Aerosol stability of bovine parainfluenza type 3 virus.

Aerosols of bovine parainfluenza type 3 virus were generated with a Devilbiss 40 nebulizer from Eagle's minimum essential medium and nasal secretion from a non-infected calf and stored in a rotating drum at temperatures of 6 degrees C or 32 degrees C and relative humidities of 30% or 90%. The aerosols were sampled at seven minutes, one, two and three hours after the start of generation with an all glass impinger (AGI-30) and titrated for infectivity in cell cultures. Physical decay was determined by a rhodamine tracer technique. Media, temperature or relative humidity had little effect on the survival of parainfluenza type 3 virus during spraying (zero to seven minutes). During aging of aerosols at 32 degrees C and 30% relative humidity, parainfluenza type 3 virus was less stable in Eagle's minimum essential medium than in nasal secretion from a noninfected calf, but at 6 degrees C and 30% relative humidity, the virus was more stable in Eagle's minimum essential medium. At 32 degrees C, the virus was less stable during aging at 90% relative humidity than at 30% relative humidity. The virus was consistently more stable during aging of aerosols at 6 degrees C than at 32 degrees C.     

The effect of vaccination of lambs with live parainfluenza virus type 3 on pneumonia produced by parainfluenza virus type 3 and Pasteurella haemolytica

Groups of 20 lambs were vaccinated with parainfluenza virus type 3 PI₃ by the intranasal (I.N.) or intramuscular route (I.M.).Approximately 6 weeks later, vaccinated and non-vaccinated lambs were challenged sequentially with PL₃, and Pasteurella haemolytica. At slaughter, 10 to 12 days after challenge, 65% of non-vaccinates and 45% of I.M. vaccinates had pneumonic lesions whereas lesions were not observed in any of the I.N. vaccinates.     

Fibro-osseous proliferation in the sternums and femurs of female B6C3F1, C57black and CD-1 mice: a comparative study

Sternums and femurs from B6C3F1, C57black and CD-1 mice, used as controls in carcinogenicity studies, were microscopically examined for the presence of fibro-osseous proliferation (syn. hyperostosis, myelofibrosis, osteofibrosis). The uterus, vagina and ovaries of the same animals were microscopically examined, particularly for the morphological changes indicative of hyperestrogenism. The incidences of each finding in each strain were compared using a chi square test to detect any interstrain variations of statistical significance. Despite the markedly high incidence of endometrial cystic hyperplasia, vaginal epithelial cell hyperplasia and hyperkeratosis, which are morphological changes indicative of hyperestrogenism in all three strains of mice, the incidence of fibro-osseous proliferation in B6C3F1 mice was markedly higher than in the other two strains and statistically significant. This could be explained by a more sustained and higher level of endogenous estradiol in B6C3F1 mice, as brought into evidence by the markedly high, and stastically significant, incidence of follicular development/atresia, with cystic formation, in the ovaries of this strain. However, genetic factors that could determine the general predisposition to fibro-osseous proliferation in B6C3F1 mice cannot be ruled out.     

Immunogenicity of bovine parainfluenza type 3 virus proteins encapsulated in nanoparticle vaccines,following intranasal administration to mice

Stimulation of long lasting, protective immunity to respiratory viruses is often difficult to achieve with conventional respiratory vaccines. Polymeric nanoparticles, incorporating viral proteins have been shown to offer sustained release of antigen, with consequent prolongued stimulation of the respiratory immune system. In this paper the efficacy of two nanoparticle vaccines (poly-lactide-co-glycolide, PLGA; polymethylmethacrylate, PMMA), incorporating proteins of bovine parainfluenza type 3 virus (BPI-3) was investigated. As a preliminary to experiments in calves, it was considered essential to demonstrate immunogenicity of the experimental vaccine in mice. Mice immunised with PLGA nanoparticles, containing BPI-3 proteins, developed higher levels of virus-specific antibody than mice immunised with the PMMA vaccine or with soluble viral proteins alone. Immunoblotting using serum from the vaccinated mice, demonstrated strong reactions against the major BPI-3 proteins.     

C57小鼠和C57BL/6 FMR1 KO小鼠剖宫产手术及其仔鼠生长情况的比较研究

目的 C57BL/6小鼠和C57BL/6 FMR1 KO小鼠剖宫产手术及其仔鼠生产情况的比较。方法将C57和FMR1两种小鼠分成两组,每组雌雄按1:1配对,通过剖宫产手术取得仔鼠,C57母鼠作为代乳母鼠,分别比较两种小鼠的妊娠时间、成功受孕时间、7 d成活率、产仔数、离乳率。结果 FMR1小鼠在成功受孕时间、7 d成活率、离乳率上与C57小鼠存在显著差异。结论通过剖宫产净化手术获得FMR1小鼠,为后续开展保种和育种工作提供重要保障。     

Characterization of parainfluenza type 3 virus isolated from the lung of a lamb with pneumonia

A virus designated DH-1 was isolated from the lung of a lamb that died during the course of an epizootic of acute respiratory tract disease. The virus contained ribonucleic acid and was sensitive to heat (56 C), lipid solvent, and acid (pH 3.0). Inoculated cell cultures absorbed and culture fluids agglutinated guinea pig erythrocytes. Morphogenic and morphologic characteristics of the isolate were compatible with those of the genus Paramyxovirus of the family Paramyxoviridae. Serologic results indicated that the virus was indistinguishable from prototype parainfluenza virus type 3.     

Bovine herpesvirus-1 (BHV-1) recombinant expressing pseudorabies virus (PrV) glycoproteins B and C induces type 1 immune response in BALB/c mice

Bovine herpesvirus 1 (BHV-1) attached poorly and penetrated into a mouse cell line, BALB 3T3/A31, but a recombinant BHV-1/TF7-6, which expresses pseudorabies virus (PrV) gB and gC genes, did attach and penetrated into cells more efficiently. In this study the gene green fluorescent protein (GFP) has been integrated into genome of BHV-1/TF7-6 and its parental line of BHV-1. When the mouse mesenteries were incubated in vitro and infected with BHV-1/TF7-6/GFP, strong fluorescence was observed while BHV-1/GFP infection hardly demonstrated fluorescence, suggesting that BHV-1 recombinant expressing PrV gB and gC can infect mouse tissue cells more efficiently than the parental BHV-1 does. When BALB/c mice were inoculated with purified BHV-1/TF7-6 or its parental BHV-1, the former induced lower level of anti-BHV-1 immunoglobulin G (IgG) than the latter did. When sub-classes of anti-BHV-1 IgG were analyzed, it was found that mice immunized with BHV-1/TF7-6 or the parental BHV-1 demonstrated the same level of IgG2a. Since anti-BHV-1 IgG1 level was lower in mice inoculated with BHV-1/TF7-6, the IgG2a:IgG1 ratio was higher in BHV-1/TF7-6 inoculated mice than in the parental BHV-1 inoculated ones. These results indicate that BHV-1/TF7-6 induces type 1 predominant immune to BALB/c mice.