BSE, bovine spongiform encephalopathy

Bovine spongiform encephalopathy, first described in 1985, has led to serious economical problems in the United Kingdom within a few years. In this review, the clinical picture, pathological findings and the etiologic and epizootiologic history of the disease are summarized. The potential threat to the Continental cattle population and the potential risk to human health are critically discussed. The known methods of diagnosis of the disease are also described.     

Sero-epidemiological and pathological studies on enzootic bovine leukosis in Turkey.

The prevalence of enzootic bovine leukosis (EBL) in Turkey was investigated by serological screenings using the agargel immunodiffusion test (AGID). A total of 4,047 blood samples obtained from 2,780 cattle between one and 14 years of age and taken in 6-8 month-intervals in three dairy farms were tested for the presence of EBL-specific antibodies. A high prevalence of EBL-sero-positive animals was found amongst cattle in two of the farms. Furthermore, recommendations based upon the regulation implemented by an expert group of the European Commission and considering the local dairy management conditions were presented.     

Efficient medium for impingement and storage of enveloped viruses

Airborne infections with pathogenic viruses play an important role in the transmission of diseases amongst men and animals. We compared several media intended for impingement of viruses from virus-contaminated air and for their preserving effect for two enveloped viruses. Sindbis (SINV) and vesicular stomatitis virus (VSV), members of the families Toga- and Rhabdoviridae, respectively, were chosen as indicator agents. Amongst the media tested, a sampling fluid consisting of phosphate buffered saline, pH 7.2, 0.5% bovine serum albumin, 0.5% gelatine (PBSplus) was most efficient to minimize the sampling stress during impingement and to preserve the infectivity SINV and VSV under stringent conditions at 37 degrees C. About 50% of virus infectivity was recovered 15.7 or 30 hours, respectively, after the beginning of storage. Thus the recommended medium is also suitable for shipment and storage of diagnostic virus samples.     

Limits and risks of biotechnology in veterinary medicine from the viewpoint of the virologist

The methods of biotechnology especially of recombinant technology opened new horizons for studies and directed control of the genomic deoxyribonucleic acid of plants, animals and men. These chances for plant breeding and animal husbandry include techniques for improved diagnosis and prophylaxis of infectious diseases or genetic defects. However, we have also to very carefully consider the potential risks of these techniques which cannot be fully evaluated at present. In this paper some of the ethic, moral and social consequences will be discussed.     

Use of synthetic peptides in virology

A survey of the potential use of synthetic oligopeptides in the field of virology is given. The potential value of synthetic peptides as vaccines and diagnostic antigens is discussed. The advantages compared to conventional vaccines as well as the limitations, e.g. the poor efficiency of immune response, are described.     

Recent developments in the epidemiology of virus diseases

There is continual variation in viral epidemics regarding clinical symptoms, duration and disappearance, and the emergence of new diseases. This can be observed in both human and animal diseases. This evolution of virus diseases is mainly related to three factors: aetiological agent, host and environment. As far as genetic alterations of the virus are concerned, two major mechanisms are involved: mutations such as recombination and reassortment; and selection for resistance or susceptibility. This review focuses on the epidemiology of newly emerged virus diseases in man and animals, such as acquired immunodeficiency syndrome, haemorraghic fevers, bovine spongiform encephalopathy, canine haemorraghic disease and respiratory syndrome in horses.     

A Universal `One-tube' RT-PCR Protocol for Amplifying Isolates of Bovine Viral Diarrhoea Virus

The increase in the knowledge of the genetic variability of BVDV and the identification of some of the genetic determinants of its pathogenicity require robust and practical tools for rapid molecular characterization of the various genotypes of this virus. This study was undertaken to develop a standard protocol for RT-PCR that allows the amplification of various parts of the genome of BVDV without the need for optimizing each individual reaction. The reaction set-up is very flexible because it consists of two pre-mixes. These are a master mix, with all the required reagents except the desired primers, which are the components of the second pre-mix and are therefore easily interchangeable between the different reactions. After adding any primer-containing pre-mix to the fixed master mix, a non-interrupted cycling protocol led to the generation of amplicons of up to 4 kbp in size in amounts sufficient for subsequent sequencing reactions. The method was applied to five different regions of the BVDV genome: (i) the well-known 5-UTR to differentiate genotypes I and II; (ii) the entire E2 gene, or an approximately 550 bp region within the E2 gene, in order to find the molecular equivalent of antigenic varieties; (iii) the entire structural protein coding region covering the Npro, capsid, E ^RNS, E1 and E2 genes; (iv) a 2.1 kbp region embracing the NS2/3 junction which is known to be cleaved in cytopathic biotypes of BVDV; and (v) the region covering the entire NS4B and NS5A/B genes. All six RT-PCRs were successfully applied using (i) primers with lengths of between 20 and 52 nucleotides, (ii) an aliquot of RNA extracted from either 10⁶ infected bovine embryonal lung cells or the same number of leukocytes from viraemic cattle, and (iii) all the genotype I and II strains of BVDV tested. The technique described was used to generate various Sindbis virus/BVDV recombinants. The correct processing of the amplicon-derived E2 glycoprotein of BVDV strain PT810 was demonstrated by its reaction with a monoclonal antibody in an immunofluorescence assay. Given the variety of RT-PCRs tested, we conclude that this universal protocol may be useful with other RNA viruses.