Bovine syncytial virus isolations

Bovine Foamy Virus: Shared and Unique Molecular Features In Vitro and In Vivo

The retroviral subfamily of Spumaretrovirinae consists of five genera of foamy (spuma) viruses (FVs) that are endemic in some mammalian hosts [1]. Closely related species may be susceptible to the same or highly related FVs. FVs are not known to induce overt disease and thus do not pose medical problems to humans and livestock or companion animals. A robust lab animal model is not available or is a lab animal a natural host of a FV. Due to this, research is limited and often focused on the simian FVs with their well-established zoonotic potential. The authors of this review and their groups have conducted several studies on bovine FV (BFV) in the past with the intention of (i) exploring the risk of zoonotic infection via beef and raw cattle products, (ii) studying a co-factorial role of BFV in different cattle diseases with unclear etiology, (iii) exploring unique features of FV molecular biology and replication strategies in non-simian FVs, and (iv) conducting animal studies and functional virology in BFV-infected calves as a model for corresponding studies in primates or small lab animals. These studies gained new insights into FV-host interactions, mechanisms of gene expression, and transcriptional regulation, including miRNA biology, host-directed restriction of FV replication, spread and distribution in the infected animal, and at the population level. The current review attempts to summarize these findings in BFV and tries to connect them to findings from other FVs.

Non-simian foamy viruses: molecular virology, tropism and prevalence and zoonotic/interspecies transmission

Within the field of retrovirus, our knowledge of foamy viruses (FV) is still limited. Their unique replication strategy and mechanism of viral persistency needs further research to gain understanding of the virus-host interactions, especially in the light of the recent findings suggesting their ancient origin and long co-evolution with their nonhuman hosts. Unquestionably, the most studied member is the primate/prototype foamy virus (PFV) which was originally isolated from a human (designated as human foamy virus, HFV), but later identified as chimpanzee origin; phylogenetic analysis clearly places it among other Old World primates. Additionally, the study of non-simian animal FVs can contribute to a deeper understanding of FV-host interactions and development of other animal models. The review aims at highlighting areas of special interest regarding the structure, biology, virus-host interactions and interspecies transmission potential of primate as well as non-primate foamy viruses for gaining new insights into FV biology.

A study of virus-like particles present in bovine nerve sheath tumours

The morphology of virus-like particles present in bovine nerve sheath tumours is described, and their origin and significance discussed. Virus-like particles were investigated using transmission electron microscopy and tissue culture. The particles were found in a number of tumours and were present either as aggregates in pseudonuclear inclusions or as budding forms associated with the plasma membrane. The latter were found only in cultured tissue. Although other cellular structures were considered it was thought that the particles represented virus, with those in pseudonuclear inclusions being an intermediate form. Both bovine syncytial virus and oncovirinae were considered as possibilities in the aetiology of the condition.

Detection of antibody to bovine syncytial virus and respiratory syncytial virus in bovine fetal serum

Batches of commercial fetal bovine serum, described by the suppliers as antibody-free, all contained antibody to bovine syncytial virus (BSV) when tested by indirect immunofluorescence. Antibody to bovine respiratory syncytial virus (RSV) was not detected in these sera. Twenty-four percent of individual fetal bovine sera contained antibody to BSV, and 14% contained antibody to RSV when tested by indirect immunofluorescence. BSV antibody titers in fetal sera from dams with high BSV antibody levels were variable but always higher than RSV antibody titers. Radial immunodiffusion studies with BSV-positive sera revealed the presence of immunoglobulin M (IgM), IgG, and IgA, but the quantity of these immunoglobulins was not directly related to the BSV antibody titers. The evidence suggests that the antibody present in fetal sera arose as the result of infection rather than from maternal transfer across the placenta.

Serological evidence for the association of bovine respiratory syncytial virus with respiratory tract disease in Alabama cattle

A serological investigation for neutralizing antibody to bovine respiratory syncytial virus (BRSV) was conducted using an antigenically related human strain of respiratory syncytial virus. Results demonstrated the effectiveness of the procedure. Sixty-seven percent of healthy, adult cattle tested were found to have antibody to BRSV. Calves in several herds were exposed to conditions to encourage development of respiratory tract disease. In three herds in which respiratory tract disease subsequently developed, the incidence of BRSV seroconversions approached 100%. In a herd in which no respiratory tract disease was detected, BRSV seroconversions indicated a high incidence of subclinical infections. It was concluded that, in this country as has been shown in others, BRSV is probably a significant pathogen of the bovine respiratory tract.