Serological studies of parainfluenza type 3 virus, bovine adenovirus type 3 and bovine respiratory syncytial virus infection in beef calves

Six serum samples were taken at monthly intervals from birth to weaning from each of 41 newborn calves in the autumn and spring calf crops of a beef cow--calf herd. The serum hemagglutination-inhibition (HI) antibody titres to parainfluenza type 3 virus (PIV-3), virus-neutralization (VN) antibody titres to bovine adenovirus type 3 (BAV-3) and bovine respiratory syncytial virus (BRSV) were determined using microtitration techniques. There was serological evidence of a significantly higher incidence of infection with BAV-3 in the fall calves than in the spring calves. Serological responses to BAV-3 were not detected in calves with VN titres of greater than 1/256. Serological evidence of subclinical infection with PIV-3 occurred mainly in late February or early March during a period of marked environmental temperature fluctuations. Serological evidence of a high incidence of infection with BRSV was obtained for both the fall and spring calf crops. Serum antibody appeared to be unable to prevent infection with BRSV. An association between infection with BRSV and clinical pneumonia was found in 3 out of 9 calves. BAV-3 infection was related to pneumonia in only 1 instance; however, there was simultaneous evidence of BRSV infection in this calf. PIV-3 infection was found to be related to pneumonia in only 1 instance. There was serological evidence of infection with BAV-3 in association with the occurrence of diarrhea in 3 calves.     

Cytotoxicity of bovine leucocytes for parainfluenza type-3 virus-infected cells.

The cytotoxic effect of bovine neutrophils, alveolar macrophages, monocytes and lymphocytes for parainfluenza type-3 (PI-3) virus-infected cells in 51chromium-release assays is described. Specific lysis of virus-infected target cells with PI-3 virus antibody and complement was first observed 8 h after infection coincident with the appearance of haemadsorption-positive cells. Specific lysis increased rapidly reaching a peak 18-24 h after infection. This increase was paralleled by the increase in the percentage of cells with surface haemagglutinin. Target cells were subsequently used in 51chromium-release assays between 18 and 20 h after virus infection. Antibody-independent killing of PI-3 virus-infected cells was observed with neutrophils, alveolar macrophages and lymphocytes. Levels of specific lysis up to 30% for neutrophils and 68% for alveolar macrophages were observed, although there was considerable variation in activity from animal to animal. Lymphocyte preparations showed levels of cytotoxicity up to 20% in some cases while monocytes had low killing ability. Addition of PI-3 virus-specific antibodies enhanced killing by neutrophils, monocytes and lymphocytes but inhibited killing by alveolar macrophages. Complement, particularly guinea pig complement, was cytotoxic for virus-infected but not for uninfected cells, and also considerably enhanced the cytotoxic effect of neutrophils and lymphocytes.     

Cytotoxic interactions between bovine parainfluenza type 3 virus and bovine alveolar macrophages

This paper describes an investigation of the cytotoxic activity of bovine alveolar macrophages for parainfluenza type 3 (PI-3) virus-infected target cells, using 51Cr release assays. Alveolar macrophages from uninfected calves were shown to be capable of killing PI-3 virus infected cells without the presence of antibody or complement (antibody-independent cell-mediated cytotoxicity). The level of killing was shown to vary from animal to animal with specific lysis values ranging from <5% to 70%. Presence of PI-3 virus antiserum was shown to inhibit, rather than enhance macrophage cytotoxicity in a dose-dependent manner, suggesting that bovine alveolar macrophages do not always exhibit antibody-dependent lysis in all cases. Following intranasal and intratracheal inoculation of calves with PI-3 virus, the level of cytotoxicity by macrophages lavaged from the lungs of the calves increased substantially, and by Day 5 post inoculation, levels of 95% to 98% specific lysis were recorded. After Day 5, the killing ability decreased rapidly to low levels. Cell-free lavage fluids, collected from PI-3 virus infected and control calves at various times throughout the experiment, were incubated with aliquots of an alveolar macrophage population from an uninfected donor calf, which initially showed a low level of killing, and were subsequently added to PI-3 virus infected target cells. The recorded levels of cytotoxicity, mirrored those which were seen with the initial macrophage effector cells from the infected and control animals, suggesting that macrophage cytotoxicity was largely controlled by extracellular factors.     

Synergistic effects of bovine respiratory syncytial virus and non-cytopathic bovine viral diarrhea virus infection on selected bovine alveolar macrophage functions.

The effect of bovine respiratory syncytial virus (BRSV) and non-cytopathic bovine viral diarrhea virus (ncpBVDV) infection on selected bovine alveolar macrophage (AM) functions was investigated. Alveolar macrophages were harvested from 2- to 6-month-old calves seronegative for BRSV and BVDV and inoculated with approximately 1 median cell culture infective dose of virus per AM. Control, BRSV infected, ncpBVDV-infected and BRSV-ncpBVDV coinfected AM cultures were evaluated for Fc receptor expression, phagosome-lysosome fusion, superoxide anion (O2-) production, and chemotactic activity on Days 1, 3, 5, and 7 post-infection. Both single and combined viral infections significantly depressed AM Fc receptor expression, phagosome-lysosome fusion, and secretion of chemotactic factors with a more significant synergistic depression seen in BRSV-ncpBVDV coinfection. Production of O2- by AM was not decreased by either BRSV or ncpBVDV infection, but was significantly decreased by coinfection with BRSV-ncpBVDV. The present study confirms previous reports of BRSV effects on AM functions and indicate that ncpBVDV affects AM functions in vitro. Coinfection with BRSV-ncpBVDV produced a synergistic depression on AM functions.     

Observations on outbreaks of respiratory disease in calves associated with parainfluenza type 3 virus and respiratory syncytial virus infection.

In four outbreaks of indoor calf pneumonia, dyspnoea was a prominent clinical finding. At necropsy it was associated with pneumonia involving the cranial lobes of the lung and severe pulmonary emphysema. Histological examination of lung tissue revealed bronchiolitis and alveolitis with alveolar epithelial cell hyperplasia and multinucleate syncytium formation. Intraalveolar haemorrhage, intra-alveolar oedema and hyaline membrane formation were also noted. In all cases parainfluenza type 3 (PI3) virus was isolated from the lungs. In each of the four outbreaks there was evidence of PI3 virus and respiratory syncitial virus (RSV) infection.     

Effect of in vitro inoculation of bovine respiratory syncytial virus on bovine pulmonary alveolar macrophage function

Viruses may predispose the respiratory tract to the development of secondary bacterial pneumonia by impairing functions of alveolar macrophages. The effects of bovine respiratory syncytial virus (BRSV) on selected functions of bovine pulmonary alveolar macrophages (PAM) were examined in vitro. Alveolar macrophages were obtained from nonsedated cattle, using a polypropylene tube passed intranasally into the lung. The PAM lavaged from the lung were allowed to adhere to glass coverslips or plastic tissue culture plates, and were exposed to BRSV for 2 hours. Control and BRSV-inoculated PAM were compared at intervals over a 72-hour period for their abilities to phagocytize and kill Staphylococcus epidermidis, rosette with and phagocytize antibody-coated sheep RBC (SRBC), phagocytize latex particles, and influence lysosomal enzyme activity. Challenge exposure with BRSV did not affect the ability of PAM to adhere and did not affect cell viability. There were numerical differences between control and BRSV-inoculated cell populations in phagocytosis and killing of S epidermidis, but these were not significant (P greater than 0.05). There was less than 5% difference in the abilities of control and BRSV-challenged PAM to phagocytize latex beads. When Fc-receptor-mediated phagocytosis of antibody-coated SRBC was compared with controls, BRSV-challenged PAM had significantly (P less than 0.05) impaired phagocytic function, which was maximal 72 hours after BRSV inoculation; the phagocytic impairment occurred in spite of normal Fc-receptor function, as determined by rosetting with antibody-coated SRBC.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characterization and identification of a bovine respiratory syncytial virus isolated from young calves.

Two identical viruses designated 371 and 375 were recovered from nasal secretions of 2 of 7 calves in a beef cow-calf herd in which calves (45 to 105 days of age) had signs of acute respiratory tract disease. The cytopathic, morphologic and physico-chemical characteristics of the isolates were those of bovine respiratory syncytial virus. Although a humoral antibody response to bovine respiratory syncytial virus was not observed, it was concluded that this virus probably had a part in the respiratory tract disease in these calves.     

Detection of antibodies and risk factors for infection with bovine respiratory syncytial virus and parainfluenza virus 3 in dual-purpose farms in Colima, Mexico

A cross-sectional study was carried out, from November 2007 to March 2008, to estimate the prevalence of and to determine risk factors associated with bovine syncytial respiratory virus (BRSV) and parainfluenza 3 virus (PIV3) in dual-purpose herds in Colima, México. One hundred and seventy-six sera from 33 herds for PIV3 and 232 sera from 44 herds for BRSV were used. Sera were analyzed by indirect ELISA for the detection of antibodies against BRSV and PIV3 in cattle herds to determine the seroprevalence of respiratory diseases. The apparent and true prevalences for PIV3 were 60.8% and 54.4% and for BRSV 52.2% and 50.8%, respectively. The percentage of herds showing at least one positive animal was 78.7% for PIV3, and 93.2% for BRSV. Age (≤12, 13-48, and >48?months old) and respiratory signs (no, yes) showed significant association (P?相似文献   

Replication of bovine respiratory syncytial virus in bovine and ovine peripheral blood lymphocytes and monocytes and monocytic cell lines

The present study compared the replication of bovine respiratory syncytial virus (BRSV) in bovine and ovine peripheral blood mononuclear cells, ovine and bovine monocytic cell lines and ovine alveolar macrophages. Low titres of virus were detected in ovine and bovine lymphocytes and monocytes 24–96 h post-exposure to the virus but there was no apparent replication of the virus in ovine alveolar macrophages during the culture period. The virus replicated to higher but statistically insignificant titres in ovine and bovine peripheral blood monocytes than in lymphocytes, with lymphocytes yielding peak titres significantly earlier. The secondary cell lines obtained from ovine liver and bone marrow also supported the replication of BRSV to high titres. The titres of BRSV in ovine and bovine lymphocytes and monocytes were significantly lower than in secondary cell lines. The addition of human recombinant tumour necrosis factor alpha after exposure to the virus or pre-incubation of ovine or bovine monocytic cells with either human recombinant interleukin 2 or phorbol myristate acetate before exposure to BRSV, did not significantly affect virus titre. Pre-incubation of cells with indomethacin or actinomycin significantly lowered virus titre (p<0.05).     

Interaction of bovine respiratory syncytial virus with bovine alveolar macrophages in vivo: effects of virus infection upon selected cell functions.

The effect of bovine respiratory syncytial virus (BRSV) upon alveolar macrophage (AM) function was investigated using an in vivo calf inoculation model. Alveolar macrophages were collected sequentially from live calves at multiple time points during the 14 day period following viral inoculation. Alveolar macrophages from bronchoalveolar lavage fluids were purified by density gradient centrifugation (> 95% AM) prior to in vitro evaluation of cell functions. There were significant but variable and inconsistent differences in the functions of AM from the BRSV inoculated calves compared to the control calves. Fc-receptor mediated phagocytosis was either increased or unchanged by BRSV inoculation. Nonopsonized phagocytosis was decreased during the early postinoculation period and later increased. There was a variable effect on AM phagosome lysosome fusion with increased fusion activity on postinoculation days 2 through 5, 7 and 12 but reduced activity on days 6 and 10. The AM respiratory burst, as measured by nitroblue tetrazolium dye reduction, was essentially unaffected with a reduction in activity on day 10 only. In this model, BRSV inoculation of calves primarily resulted in an alteration of the membrane associated phagocytic functions of the alveolar macrophages (p < 0.05).     

Reinfection of lambs with bovine respiratory syncytial virus.

Eight lambs which were experimentally infected with bovine respiratory syncytial virus (RSV) when they were six to eight weeks old were challenged with the same virus seven months later. After reinfection, lambs developed mild clinical disease and the virus was isolated from nasal swabs from three lambs and peripheral blood from two lambs. Reinfection resulted in changes in peripheral blood cell populations. There was an early increase in the number of CD8+ T lymphocytes and B (LCA p220+) lymphocytes but the proportions of CD4+ and CD4-CD8- T lymphocytes were significantly reduced. Peripheral blood mononuclear cells obtained from lambs reinfected with bovine RSV showed significantly higher responses to bovine RSV antigen in vitro than those obtained from control lambs but their responses to the mitogen phytohaemagglutinin were significantly lower than in control lambs. RSV-specific IgG, IgM and IgA levels of serum samples obtained 10 days after challenge were significantly higher than those of serum samples obtained before challenge.     

Effect of "in vitro" exposure of bovine alveolar macrophages to different strains of bovine respiratory syncytial virus.

A vaccine strain of respiratory syncytial (RS) virus and an isolate from pneumonic calves (AC2) were inoculated onto cultures of bovine alveolar macrophages recovered by lung lavage, and the functional properties of the cells observed over a period of 10 days. In most cultures no infectious virus was produced although immunofluorescence indicated the presence of virus antigens in some cells. No significant difference was noted between infected and control macrophage cultures in their capacity to phagocytose latex particles (neutral phagocytosis), although the ability to phagocytose complement-coated Candida krusei cells was affected, particularly with the AC2 strain after 6 days. Killing of C. krusei cells was slightly affected by infection of macrophages with the vaccine strain and was dramatically affected by infection with strain AC2. C3b and Fc receptor expression was adversely affected by both virus strains. Production of neutrophil chemotactic factors was increased in cultures infected with both strains, but was greater with AC2, suggesting that some properties of the cells were activated.     

Serological titers to bovine herpesvirus 1, bovine viral diarrhea virus, parainfluenza 3 virus, bovine respiratory syncytial virus and Pasteurella haemolytica in feedlot calves with respiratory disease: associations with bacteriological and pulmonary cytological variables.

Acute and convalescent serum samples were taken from 59 calves with signs of respiratory disease (cases) and 60 clinically normal animals (controls) during their first month in the feedlot. Sera were analyzed for antibodies to bovine parainfluenza 3 (PI3) virus by hemagglutination inhibition, to bovine viral diarrhea (BVD) virus, bovine respiratory syncytial (BRS) virus and bovine herpesvirus 1 (BHV1) by virus neutralization, and to Pasteurella haemolytica by indirect agglutination (PhIA) and cytotoxin neutralization (PhCN) tests. There was minimal evidence of serological activity to BHV1. Serological activity to the other agents occurred commonly and the prevalence of acute titers and their mean values was similar in case and control groups. Mean convalescent PI3 and P. haemolytica (PhIA) titers were higher in controls than cases (p < 0.01) but, otherwise, convalescent titers did not differ between groups. The incidence of seroconversion was similar in both groups for all agents except for PI3 virus which was more frequent in controls than cases (p < 0.0001). There was a positive association between PhIA and CN seroconversion and isolation of P. haemolytica from bronchoalveolar lavage (BAL) fluid (p < 0.1). The measure of agreement (kappa) between seroconversion with the P. haemolytica PhIA and PhCN tests was 0.51. Bacteriological and cytological evaluations of the respiratory tract were made using BAL. No associations were evident between serological titers and pulmonary cytology. A multivariate logistic analysis was used to evaluate associations between disease status and serological, bacteriological and cytological data. Cases were positively associated with the presence of neutrophils and Pasteurella multocida in BAL fluid and negatively associated with PI3 virus and PhIA seroconversion.     

Efficacy of an intranasal modified live bovine respiratory syncytial virus and temperature-sensitive parainfluenza type 3 virus vaccine in 3-week-old calves experimentally challenged with PI3V

Two experimental parainfluenza type 3 virus (PI3V) challenge studies were undertaken to evaluate the efficacy of a single intranasal dose of an attenuated live vaccine containing modified live bovine respiratory syncytial virus (BRSV) and temperature-sensitive PI3V in 3-week-old calves. In the first study, vaccine efficacy was evaluated in colostrum deprived calves. Nasal shedding of PI3V was highly significantly reduced in vaccinated calves challenged 10 days or 21 days after vaccination. In the second study, vaccine efficacy was assessed in calves with maternal antibodies against PI3V by challenge 66 days post-vaccination. Vaccination also significantly reduced PI3V excretion after challenge in this study. In both studies, clinical signs after challenge were very mild and were not different between vaccinated and control calves.     

Immunofluorescence in the serological diagnosis of parainfluenza type 3 and respiratory syncytial virus infection in calves

The fluorescent antibody (FA) test is compared with the haemagglutination inhibition (HI) test for parainfluenza virus type 3 (PI-3) and virus neutralisation (VN) test for respiratory syncytial (RS) virus for detection and titration of virus-specific antibodies. In experimentally inoculated calves PI-3 and RS virus FA tests detected seroconversion at the same time as HI and VN tests, however, in serially diluted sera, the FA test was positive to higher dilution. In studies with paired samples from calves from four farms with respiratory problems, the FA test gave similar results to PI-3 HI and RS virus VN tests. Large increases in antibody titre to RS virus detected by FA and VN tests indicated this was the problem on two of the farms. Individual animals showed large rises to PI-3 by FA and HI test on three farms. It is concluded that the FA test provides a rapid and sensitive alternative to the more conventional serological tests for respiratory viruses.     

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.     

新疆阿克苏地区牛传染性鼻气管炎病毒与牛副流感病毒3型感染的检测

为调查阿克苏地区是否存在牛传染性鼻气管炎病毒(IBRV)与牛副流感病毒3型(BPIV-3)的感染,从阿克苏两个规模化奶牛场采集1月龄以内可疑发病犊牛鼻液样品18份,采用双抗体夹心ELISA方法检测两种病毒的抗原,PCR方法检测牛传染性鼻气管炎病毒gD基因,RT-PCR方法检测牛副流感病毒3型的gM基因。结果表明,ELISA方法检测IBRV和BPIV-3的感染率分别为22.22%和0%;PCR方法检测IBRV的感染率为72.22%;RT-PCR检测BPIV-3的感染率为44.44%;同时患有两种病毒的检出率为22.22%。说明在阿克苏地区存在IBRV与BPIV-3的感染,且存在两种病毒的双重感染。     

Pulmonary lesions induced by 3-methylindole and bovine respiratory syncytial virus in calves

Our objectives were to describe the ultrastructural morphogenesis of pulmonary lesions induced by 3-methylindole in 30- to 45-day-old Holstein calves and to determine whether toxic exposure to 3-methylindole exacerbates pulmonary lesions induced by bovine respiratory syncytial virus. Administration of 3-methylindole (0.25 g/kg) to calves resulted in interstitial edema and ultrastructural swelling of type-I alveolar epithelial cells and nonciliated bronchiolar epithelial cells as early as 4 to 6 hours after intraruminal administration. More severe alveolar edema containing protein was associated with swelling of capillary endothelial cells at 2 days after administration. Proliferation of type-II alveolar epithelial cells was first observed at 2 days after 3-methylindole administration, and marked hyperplasia of type-II epithelial cells and nonciliated bronchiolar epithelial cells was evident by 4 days after administration. Pulmonary cytochrome P-450 monooxygenase concentrations decreased significantly (P less than 0.001) by 12 hours after administration and did not increase significantly again by 8 days after administration. Calves were inoculated with bovine respiratory syncytial virus 3 days after administration of 3-methylindole, and pulmonary lesions were assessed 5 days after viral inoculation. Viral replication was demonstrated by fluorescence microscopy for viral antigen or by transmission electron microscopy in ciliated and nonciliated airway epithelial cells. Viral antigen was identified infrequently in alveolar macrophages and in type-II alveolar epithelial cells. 3-Methylindole exposure in calves did not result in more widespread distribution of viral antigen in alveolar tissue of respiratory syncytial virus-inoculated calves or in significant enhancement of viral pneumonia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Synergistic effects of concurrent challenge with bovine respiratory syncytial virus and 3-methylindole in calves.

OBJECTIVE: To evaluate the potential synergy between bovine respiratory syncytial virus (BRSV) and 3-methylindole (3MI) in inducing respiratory disease in cattle. ANIMALS: 20 mixed-breed beef calves. PROCEDURE: A 2 X 2 factorial design was used, with random assignment to the following 4 treatment groups: unchallenged control, BRSV challenge exposure (5 X 10(4) TCID50 by aerosolization and 5.5 X 10(5) TCID50 by intratracheal inoculation), 3MI challenge exposure (0.1 g/kg of body weight, PO), and combined BRSV-3MI challenge exposure. Clinical examinations were performed daily. Serum 3MI concentrations, WBC counts, PCV, total plasma protein, and fibrinogen concentrations were determined throughout the experiment. Surviving cattle were euthanatized 7 days after challenge exposure. Pulmonary lesions were evaluated at postmortem examination. RESULTS: Clinical respiratory disease was more acute and severe in cattle in the BRSV-3MI challenge-exposure group than in cattle in the other groups. All 5 cattle in this group and 3 of 5 cattle treated with 3MI alone died or were euthanatized prior to termination of the experiment. Mean lung displacement volume was greatest in the BRSV-3MI challenge-exposure group. Gross and histologic examination revealed that pulmonary lesions were also most severe for cattle in this group. CONCLUSIONS AND CLINICAL RELEVANCE: Feedlot cattle are commonly infected with BRSV, and 3MI is produced by microflora in the rumen of all cattle. Our results suggest that there is a synergy between BRSV and 3MI. Thus, controlling combined exposure may be important in preventing respiratory disease in feedlot cattle.