The traditional approach to diagnosis of virus infectians by isolation of the causative virus is usually both slow and expensive. More recently, the emphasis has been on the direct detection of viruses or viral antigens in clinical specimens. This can be done using established techniques such as immunofluorescence or electron microscopy, or by newly developed biochemical methods. The purpose of this meeting was to review these and other developments in the laboratory diagnosis of virus infections. We would like to thank all those who contributed to the success of this meeting. In particular, we are grateful to the CEC for financial sponsorship, to Professor C. Dow, Director of the Veterinary Research Laboratories, for help in organising the meeting, and to Miss B. Hamilton for her excellent typing of the manuscripts. M S McNulty J B McFerran VII CONTENTS Page Preface V VIRAL DIAGNOSIS BY TIMMUNOFLUORESCENCE P. S. Gardner APPLICATIONS OF IMMUNOFLUORESCENCE IN VETERINARY VIRAL DIAGNOSIS M. S. McNulty and G. M. Allan 15 TAGGING OF VIRAL ANTIGENS USING IMMUNOPEROXIDASE . AND IMMUNOOOLD TEGINlQUES R. Ducatelle, F. Castryck and J. Hoorens 27 DETECTION OF BVD VIRUS IN VlRAEMIC CATTLE BY AN INDIRECT IMMUNOPEROXIDASE TEGINIQUE A. Meyling 37 VIRAL DIAGNOSIS BY ELECTRON MICROSCOPY J. D. Almeida 47 CAPTURE ASSAYS FOR THE DETECTION OF VIRUS-SPECIFIC IgM ANTIBODY R. S. Tedder 60 DETECTION . AND IDENTIFICATION OF PAPILLOMAVIRUSES IN BENIGN . AND MALIGNANT 'TIlmJRS OF CATTLE M. S. Campo 72 DETECTION OF VIRAL NUCLEIC ACIDS IN CELL CULTURES .

This book is based on the proceedings of a seminar on acute viral in fections of poultry, which was held in Brussels on 13-14 June 1985. The aim of the seminar, which was sponsored by the CEC, was to gather infor mation on those infections of immediate or increasing importance. It is hoped that dissemination of this information will make it easier to har monize diagnostic and control measures throughout the member states of the EEC. Several points emerge from recent outbreaks of highly pathogenic avian influenza. In view of the apparent change in pathogenicity of the virus involved in the outbreak in the USA, infections of domestic poultry, particularly with H5 and H7 sub-types, should be regarded as a potential threat, even if the viruses involved are of low pathogenicity. The reasons for the amount of lateral spread which occurred in the USA outbreak are still not clear, and it can not be assumed that future outbreaks of highly pathogenic avian influenza will tend to be self-limiting, as in the past. The importance of denying access of wild birds, particularly water fowl, to domestic poultry needs to be re-emphasised. Lastly, there appears to be increasing support for a combination of slaughter and ring vaccination to control future outbreaks of spreading avian influenza."