Sites of Replication of Bovine Respiratory Syncytial Virus in Naturally Infected Calves as Determined by In Situ Hybridization

Viuff, Birgitte; Uttenthal, Åse; Tegtmeier, Conny; Alexandersen, Søren

doi:10.1177/030098589603300403

Cited by 51 publications

(58 citation statements)

References 13 publications

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“…On the contrary, samples collected after PID 8 were often negative in the RT-PCR despite severe lung tissue damage. By immunohistochemistry and in situ hybridization BRSV was previously detected in the caudal lung lobes from experimentally and naturally infected calves 26 (unpublished results). These data suggested that although BRSV can be detected in apparently unaffected parts of the lungs at the early stages of BRSV infection, immunopathologic mechanisms might be responsible for the more severe pathologic changes seen at later stages of the infection.…”

Section: Discussionmentioning

confidence: 83%

Diagnosis of Enzootic Pneumonia in Danish Cattle: Reverse Transcription-Polymerase Chain Reaction Assay for Detection of Bovine Respiratory Syncytial Virus in Naturally and Experimentally Infected Cattle

Larsen¹,

Tjørnehøj²,

Viuff³

et al. 1999

J VET Diagn Invest

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Abstract.A reverse transcription-polymerase chain reaction (RT-PCR) assay was developed for detection of bovine respiratory syncytial virus (BRSV) in lung tissue of naturally and experimentally infected cattle. Primers were selected from the gene coding the F fusion protein, which is relatively conserved among BRSV isolates. The RT-PCR assay was highly specific, it yielded positive reactions only when performed on BRSVinfected cell cultures or tissues. The detection limit of the RT-PCR assay was assessed as 5 TCID 50 . BRSV was detected in tissues of the respiratory tract and in the tracheobroncheal lymph node of calves euthanized 2-8 days after experimental infection with BRSV, whereas samples of other tissues and samples from mock-infected animals were negative at all time points. Examination of lung samples from 8 different regions of the lungs revealed that although the virus was most often found in the cranioventral lobules, it was frequently present in all lung lobules. Microbiologic examinations of all acute fatal cases of pneumonia (135 animals) in cattle submitted for diagnostic purposes during 1 year revealed that Actinomyces pyogenes (11%), Haemophilus somnus (10%), Pasteurella sp. (7%), and Pasteurella haemolytica (7%) were the most common bacterial agents found in the lungs. BRSV was identified using a conventional antigen enzyme-linked immunosorbent assay (ELISA) in 23 (17%) animals. The established BRSV-specific RT-PCR assay yielded positive results for the same 23 animals. In addition, 10 animals that were negative with the ELISA were positive with the RT-PCR assay. These results indicates that the RT-PCR assay can be a sensitive, reliable alternative to conventional diagnostic procedures.Respiratory disease is one of the most important health problems in young Danish cattle, resulting in substantial financial losses for the industry. 4,22 Approximately 20% of the bovine samples submitted to the Danish Veterinary Laboratory (DVL) for diagnostic purposes originate from cattle with a history of respiratory symptoms. Bovine respiratory syncytial virus (BRSV), Pasteurella, Haemophilus somnus, and Actinomyces pyogenes are the pathogens most often associated with pneumonia. 22,13 More sensitive diagnostic tests are needed; in approximately half of the cases submitted to DVL with a history of respiratory disease, no pathogens are identified (Tegtmeier et al., unpublished). More sensitive diagnostic methods for detection of bacterial pathogens have recently been developed. 21 At present, antigen enzyme-linked immunosorbent assays (ELISAs) are used for detection of From the Danish Veterinary Laboratory,

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Section: Discussionmentioning

confidence: 83%

Diagnosis of Enzootic Pneumonia in Danish Cattle: Reverse Transcription-Polymerase Chain Reaction Assay for Detection of Bovine Respiratory Syncytial Virus in Naturally and Experimentally Infected Cattle

Larsen¹,

Tjørnehøj²,

Viuff³

et al. 1999

J VET Diagn Invest

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“…The major IFN-producing cell in the respiratory tract following BRSV infection is not known. Ciliated epithelial cells are the main sites of virus replication, although virus can also be detected in nonciliated cells and in both type I and type II pneumocytes (6,7,57). The ability of BRSV to induce IFN in plasmacytoid dendritic cells (DCs), which are major IFN-producing cells in vivo (11), is not known.…”

Section: Discussionmentioning

confidence: 99%

Role of Alpha/Beta Interferons in the Attenuation and Immunogenicity of Recombinant Bovine Respiratory Syncytial Viruses Lacking NS Proteins

Valarcher

Furze

Wyld

et al. 2003

J Virol

140

133

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Bovine respiratory syncytial virus (BRSV) is an enveloped, nonsegmented, negative-stranded RNA virus and is a major cause of respiratory disease in young calves (44). BRSV is closely related to human RSV (HRSV), which is a major cause of respiratory disease in young children (10), and the epidemiology and pathogenesis of infection with these viruses are similar (44). These features make BRSV infection in calves a good model for the study of HRSV. HRSV and BRSV belong to the Pneumovirus genus within the Paramyxoviridae family. One of the major differences between this genus and all the other Paramyxoviridae is the presence of two nonstructural (NS) genes called NS1 and NS2. These genes code for two proteins, which are abundantly transcribed in virus-infected cells. Comparison of the sequence of the NS proteins of BRSV with that of HRSV subgroup A and B reveals amino acid identities of 69 and 68% for the NS1 protein and 84 and 83% for the NS2 protein, respectively (8, 39).The role(s) of the NS proteins is not fully defined. They are not essential for virus replication in vitro, although the growth of recombinant HRSV and BRSV lacking these proteins is attenuated in cell culture (8,25,42,51). There is evidence that the HRSV NS1 protein coprecipitates with the M protein (19), and in experiments using HRSV minigenomes, the NS1 protein appears to be a strong inhibitor of viral RNA transcription and replication (1). The NS2 protein also appears to be a transcriptional inhibitor but at a lower level than is the NS1 protein (1). The NS2 protein colocalizes with the P and N proteins in infected cells (60) but does not coprecipitate with any viral protein (19). In addition, the NS1 and NS2 proteins of BRSV and HRSV mediate resistance to the antiviral action of alpha/beta inferferons (IFN-␣/␤) (3, 42).Anti-IFN activity has been described for accessory proteins for a number of other negative-stranded RNA viruses. Of those characterized to date, some block the IFN response by hindering the late-stage activation of antiviral genes. For example, the C protein of Sendai virus inhibits STAT1 activation by hampering phosphorylation and by increasing instability (21, 64) and the V protein of simian virus 5 inhibits the activation of IFN-responsive genes by targeting STAT1 for proteasome-mediated degradation (13). Other viral accessory proteins, such as influenza A virus NS1 protein and Bunyamwera virus NSs protein, inhibit the production of IFN-␣/␤ (58, 61).

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“…At necropsy, a broncho-interstitial pneumonia may be observed [19,161]. Areas of the cranio-ventral parts of the lung are consolidated and a mucopurulent discharge may be seen from the bronchus and small bronchi.…”

Section: Clinical Signs Of Disease and Pathologymentioning

confidence: 99%

“…BRSV replicates primarily in the superficial layer of the respiratory ciliated epithelium and replication can also be detected in type II pneumocytes [161,162]. Although BRSV is cytopathic in tissue culture, little or no cytopathic effects are seen following infection of differentiated bovine airway epithelial cell cultures, in vitro 3 .…”

Section: Pathogenesis Of Brsvmentioning

confidence: 99%

Bovine respiratory syncytial virus infection

Valarcher¹,

2007

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-Bovine respiratory syncytial virus (BRSV) belongs to the pneumovirus genus within the family Paramyxoviridae and is a major cause of respiratory disease in young calves. BRSV is enveloped and contains a negative sense, single-stranded RNA genome encoding 11 proteins. The virus replicates predominantly in ciliated respiratory epithelial cells but also in type II pneumocytes. It appears to cause little or no cytopathology in ciliated epithelial cell cultures in vitro, suggesting that much of the pathology is due to the host's response to virus infection. RSV infection induces an array of pro-inflammatory chemokines and cytokines that recruit neutrophils, macrophages and lymphocytes to the respiratory tract resulting in respiratory disease. Although the mechanisms responsible for induction of these chemokines and cytokines are unclear, studies on the closely related human (H)RSV suggest that activation of NF-κB via TLR4 and TLR3 signalling pathways is involved. An understanding of the mechanisms by which BRSV is able to establish infection and induce an inflammatory response has been facilitated by advances in reverse genetics, which have enabled manipulation of the virus genome. These studies have demonstrated an important role for the non-structural proteins in anti-interferon activity, a role for a virokinin, released during proteolytic cleavage of the fusion protein, in the inflammatory response and a role for the SH and the secreted form of the G protein in establishing pulmonary infection. Knowledge gained from these studies has also provided the opportunity to develop safe, stable, live attenuated virus vaccine candidates.

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Sites of Replication of Bovine Respiratory Syncytial Virus in Naturally Infected Calves as Determined by In Situ Hybridization

Cited by 51 publications

References 13 publications

Diagnosis of Enzootic Pneumonia in Danish Cattle: Reverse Transcription-Polymerase Chain Reaction Assay for Detection of Bovine Respiratory Syncytial Virus in Naturally and Experimentally Infected Cattle

Diagnosis of Enzootic Pneumonia in Danish Cattle: Reverse Transcription-Polymerase Chain Reaction Assay for Detection of Bovine Respiratory Syncytial Virus in Naturally and Experimentally Infected Cattle

Role of Alpha/Beta Interferons in the Attenuation and Immunogenicity of Recombinant Bovine Respiratory Syncytial Viruses Lacking NS Proteins

Bovine respiratory syncytial virus infection

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