key: cord-0038858-vcdjli3d
authors: Schat, K.A.
title: Biotechnology applied to the diagnosis of animal diseases: Scientific and technical review, vol. 12 no. 2, June 1993. Office International des Epizooties, Paris, France, 1993, 353 pp., US$40.00/FrF200, ISBN 92-9044-323-5.
date: 2002-10-31
journal: Prev Vet Med
DOI: 10.1016/0167-5877(94)90039-6
sha: 25deb795eb9772c406e19088b8c27521afbdbbaa
doc_id: 38858
cord_uid: vcdjli3d

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On the practical side, the layout of both books is inadequate. The type face is small, justification is irregular, and the heading and sub-heading scheme is confusing. These layout problems make the book unnecessarily difficult to read and are unacceptable for books as costly as these. Nevertheless, this is not a reason to overlook the material.

All things considered, either the Handbook, containing sample size tables, or the Practical Handbook, accompanied by IBM or Macintosh compatible software, will be useful tools for veterinary epidemiologists that are involved in clinical trials or that consult for other investigators who are planning clinical trials.

Although the text material contained in the books serves as a useful review of some important aspects of clinical trials, the text material should not be looked to as a major reference resource on clinical trials. Once one is familiar with the basis for the sample size estimations, the tables or software will serve as a very quick and simple-to-use sample size estimating resource. In view of prices and ease of use, I recommend the Practical Handbook in preference to the Handbook. The rapid and continuing development of biotechnology has led to the introduction of new techniques for its use in animal health surveillance and disease control. The objective of this book is to provide veterinarians and others working in animal health surveillance with an overview of the potential applications and problems associated with these new techniques. For this purpose, a number of papers were selected that were presented at the Vlth Symposium of the World Association of Veterinary Laboratory Diagnosticians in Lyon (France) in June 1992. The book contains six general review papers as well as 16 research papers on detection of viral and bacterial agents and one paper on detection of trypanosomes in camels.

Four of the review papers are focused on different aspects of the ELISA and the use of monoclonal antibodies in ELISAs. Potential applications of biotechnology-derived vaccines and reagents are discussed in another review paper. A brief overview of published applications of detection of DNA by hybridization and Polymerase chain reaction (PCR) is also given. The lack of an editor is sorely missed in the review papers. As a consequence, the papers are not well coordinated resulting in considerable overlap in information in some and a lack Of information in others. The virology papers are basically focused on diseases in cattle and swine. Different ELISA-based detection techniques for bovine viral diarrhea are discussed in three papers. In two other papers, techniques are described for the detection of antibodies against porcine reproductive and respiratory syndrome virus and transmissible gastroenteritis coronavirus in swine. The major emphasis of the bacteriology papers is directed towards the detection of Mycoplasma species (four papers) by PCR and ELISA and Mycobacterium paratuberculosis (three papers) by ELISA. Although most of the papers were written in English, a few papers were published in French and one paper was included with the complete text in English, French and Spanish. This approach fragments the book making it less attractive without satisfying the needs of scientists lacking knowledge of English. It would have been better to take the approach of the Pan American Health Organization and publish separate volumes in these languages if the publisher wanted to reach a wider audience.

Although the central theme of the book is the use of biotechnology in the diagnosis of animal diseases, the book is limited in its scope and it is mostly directed towards only two of the older 'biotechnology' techniques--monoclonal antibodies and ELISA. The focus of the review papers is not always clear. On the one hand, some review papers provide detailed information, such as on the incubation times of reagents for ELISAs, but this information is not detailed enough to be useful as a practical guide. On the other hand~ a survey is provided in which disease agents have been detected by PCR but without giving detailed information on those tests. Unfortunately, an in-depth discussion is lacking on the possibilities and pitfalls of the use on the newer techniques such as PCR, reverse transcriptase (RT) PCR and ligase chain reaction for the detection of DNA or RNA viruses and virus-specific transcripts. A similar problem exists with the research papers. It is not clear why these papers were selected. The topics discussed in this section are certainly not describing innovative new ways to apply molecular-based approaches to detect the presence of animal pathogens.

Two important aspects of potential applications of biotechnology in animal health surveillance were not discussed: the use of non-radioactive detection methods for DNA and the use of marker vaccines. The use of PCR techniques for animal health surveillance will only become practical if commercial kits are available using non-radioactive detection methods. For example, the use of anti-digoxigenin antibodies or FAb fragments allows the detection of PCR-amplified DNA fragments labelled with digoxigenin-dUTP. An elegant application has been described elsewhere by Suzuki et al. ( 1992 ) . They captured digoxigenin-labelled DNA fragments of human immunodeficiency virus (HIV) by hybridization with biotinylated probes and this solution was added to streptavidin-coated microtiter plates. The presence of digoxigenin-labelled fragments were detected by alkalinephosphatase conjugated anti-digoxigenin antibodies. It is to be expected that this type of approach will become practical within the next few years for use in animal health surveillance.

One of the major problems in the surveillance of animal diseases and eradication of disease agents is the differentiation between vaccine viruses and wild-type challenge viruses. The use of vaccines lacking specific genes and the development of diagnostic tests to differentiate between these deletion mutants and field strains eliminates this problem. A good example of engineered deletion vaccines are the Aujeszki's disease vaccine lacking the gE (formerly named gI) gene (Van Oirschot et al., 1990; Van Oirschot, 1992) . The use of this type of biotechnologyderived vaccines is already required by law in The Netherlands and Belgium and these vaccines may lead to eradication of the wild-type virus. It is also possible to use these deletion vaccines as vectors for recombinant vaccines. An in depth discussion of this type of approach for the surveillance and control of important animal diseases is missing in this book.

In conclusion, this book does not offer enough new information for the specialist, but it may have value for the general reader interested in the application of ELISAs in veterinary medicine.

College of Veterinary Medicine Ithaca, NY 14853 USA

Chemiluminescent microtiter method for detecting PCR amplified HIV-1 DNA

Properties of GI-negative vaccines and companion diagnostic tests for the eradication of Aujeszky's disease

Marker vaccines, virus protein-specific antibody assays and the control of Aujeszky's disease