Prevention and control of yellow fever in Africa

Book Reviews Conquest of Viral Diseases: A Topical Review of Drugs and Vaccines J.S. Oxford and B. Oberg Elsevier, Amsterdam, New York, Oxford, 1985, 740 pp., US $157.50 It is not usual for a book of such depth and scope to be produced by just two authors. This is made possible by the expert knowledge on virus vaccines of the first author (J.S.O.) finding a match in the understandings of the drug area in the second author (B.O.). This synergism has led to the emergence of a work of great value to those who are interested in or engaged in the pursuit of improved or new vaccines and drugs to combat diseases caused by viruses. Thus in the area defined by those viruses which incapacitate humans (a feature which might have been incorporated into the title of the book) there is a wealth of information much of which is easy to access via clear and well laid out tables of the knowledge which is available and the references for further study. The plan of the book is also exemplary. It begins with two overview chapters which provide a readable perspective for the appreciation of what is to follow when the particular virus types are to be dealt with, each in its separate chapter. Also each chapter is provided with a summary which gives (in most cases) the present state of play. In addition there are sections on the disease symptomology, epidemiology and extended reviews of current practice in both the prophylactic area as well as the therapeutic possibilities. Notwithstanding the many excellent qualities of the book, I find that one of the central views propounded may not necessarily enable those who are engaged in the research and development of virus vaccines and drugs to treat virus induced illness to come to the most useful answer in the shortest time. In short it is held that the way ahead is for 'the application of logic and scientific rationality to the derivation of the next generation of useful materials'. If the lessons derived from the emergence of agents which have successfully combated disease in the past are to provide the guidelines for future successes, then it would seem that what has been neglected in the urgings of our two authors is the application of what might be called 'rationalized practices'. The past has shown us that there are a number of approaches to the derivation of useful materials to alleviate the threat or presence of disease. Such approaches include: systems of screening possible materials for beneficial effects; the technologies of virulent organism attenua-

tion by either looking for a similar virus in a different species of animal or multiple passaging of a pathogenic virus in foreign tissue cultures; the use of a variety of physical and chemical methods for the destruction of the ability of a virus to replicate without destruction of the basis for immunogenicity; and the juxtapositioning of viral derivatives with materials which can potentiate the responses of the immune system to the applied stimulus. Many of the successes achieved have been by assaying materials derived from the application of such practices without any foreknowledge or reason for supposing that one such material would be any more successful than any other of a similar type. However the scale of the number of attempts has been such that many useful materials have resulted. There is no doubt that the knowledge and understanding which have been gained through the application of the techniques of molecular biology and monoclonal antibody analysis of putative immunogens have provided those whose task it is to develop new vaccines with a new dimension in which to conduct their thinking and on which to base either their rational new designs for vaccines or their take off points for a series of random searches based on the practices of previous workers' successes in the field. This latter approach is more fully construed as one which not only uses the new knowledge in its search for improved or new materials p e r se but also incorporates the new knowledge in improved ways in which the traditional practices of arriving at more useful materials are applied. There is thus little value in promulgating the view that with the new knowledge comes the opportunity for the rational design of vac-

cines and drugs presumably by the 'scientist' working as a gifted individual. Rather, there is now an even greater need for large well funded teams of people who can apply all the available knowledge in conjunction with the tried and tested practices of the pioneers who will arrive at the successful products of tomorrow first. It was not by accident that Paul Erlich tried 606 compounds before he found one that worked or that Calmette and Gurrin worked for 13 years to attenuate the tubercule bacillus but was by recognizing the prospects of success and putting in the work to achieve those prospects. Knowledge, however construed, however detailed, however exhaustive will probably never be sufficient to arrive at materials which will carry our societies' well-being forward. It is in the light of the above that I see the value of the synthetic peptides as adjuncts to the aquisition of information and on occasion as valuable therapeutic or prophylactic materials. The latter value may, however, be somewhat sporadic and certainly neither the answer to many of the difficult problems in immunogenesis nor the answer to the purists' goal of the totally defined prophylactic or therapeutic. Apart from this bias towards the pure and the scientific and away from a recognition of the reality of the profound consequences of the activities of the regulatory agencies on the emergence of new products and on the influence that the extended gestation period has on that new product's cost, this book is a fully comprehensive statement of the realities of man's fight against virus disease in the early 1980's. Clearly new chapters have to be wrought for HIV and hepatitis but that is for the future and no doubt new editions will be so fortified. For the present there is much here from which we can learn and on which we can base our efforts for progress.

R.E. Spier

Prevention and Control of Yellow Fever in Africa WHO Office of Publications, Geneva, 1986, 94 pp., Sw.Fr. 17, ISBN 92-4-156091-6 The purpose of this book, as described in the preface, is to provide 'practical guidance for diagnosis, surveillance, management of cases and epidemics, and prevention of disease'. To attempt to fulfil this within less than 100 pages may seem an ambitious task indeed, but the publication succeeds remarkably well. The first few chapters give a succinct introduction to the disease, outlining its

historical origins and clearly demonstrating the seriousness of yellow fever as a public health problem. The authors draw particular attention to the fact that although yellow fever in man is a preventable disease through vector control and vaccination, it is still a major public health problem in tropical areas of the world, largely due to complacency in applying the control measures. The brief chapter describing the virus itself is

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exemplary in highlighting the important classical experiments with yellow fever virus and also including very recent nucleotide sequence data which will be invaluable in at last elucidating the replication strategy of the flaviviruses. The chapters dealing with the epidemiology of the disease and clinical diagnosis are clearly written with several most useful tables and should thus enable the educated but inexperienced worker in the field to recognize the disease, assess the extent of epidemics and understand the importance of the control measures which must be taken. The chapter on control and prevention contains several tables which will be a useful source of reference to all field workers. Those dealing with the suitability, resistance and spraying conditions for insecticides will be a valuable ready reference for those involved in vector control. The chapter also contains a fairly comprehensive account of vaccination procedures as well as a relatively detailed description of the contraindications and complications which can arise through mass vaccination programmes. The final chapter in this book deals with national and regional strategies for combating vector-borne diseases. The

principles laid out here should enable the public health administrators to appreciate and implement a comprehensive control strategy and should also enable the worker in the field to appreciate the part they play in the overall eradication strategy. In conclusion I found the book a clear and concise account of the many diverse political and scientific procedures which must be implemented in order to control yellow fever. The book obviously has gained a great deal by combining the expertise and experience of a number of recognized experts in yellow fever, and the 'rapporteur' must be congratulated in integrating these diverse skills to produce a clear and precise final product. My only critisisms are first that I doubt if only 64 references are adequate to represent the large and diverse field of yellow fever research. Secondly, although the book is attractively produced and clearly printed, the relatively poor quality of paper and binding would be a disadvantage. This problem could be particularly enhanced as the book is clearly intended to be a frequently used handbook by workers in the field in tropical countries.

J.R. Stephenson

Vaccine Supply and Innovation Committee on Public-Private Sector Relations in Vaccine Innovation, Institute of Medicine, National Academy of Sciences National Academy Press, Washington, DC, 1985, 210 pp., ISBN 0-309035449 As stated by Dr J.P. Sanford (Chairman) in the preface, 'vaccines are an elegant solution to one of the perennial problems of the human race - infectious disease'. Though the potential savings in dollars and human misery are phenomenal, the ultimate possibilities have been far from realized. This is especially distressing at the dawn of a new era in biotechnology that provides approaches and solutions to problems that, until

recently, were considered intractable. The shortfall in development and utilization of vaccines is explicable in a maze of interrelating problems and circumstances that may only be resolved slowly and in stepwise progression. These problems are focused principally on a triumvirate of institutions and workers that include (a) basic research creators (usually academia and government but sometimes industry), (b)

Progress in Medical Virology, Vol. 33 Editor: J.L. Melnick, S. Karger AG, Basel, 1986, 182 pp., £58.50. ISBN 3-8055-4155-4 This series is consistent in providing high quality reviews covering all aspects of virology. Volume 33 is no exception and contains an interesting blend of subjects including human papillomaviruses, herpes simplex latency, cytomegalovirus, transmissable encephalopathy agents (e.g. scrapie and CreutzfeldtJakob disease) and persistent autonomous parvovirus infection (Aleutian disease). In addition there is an excellent review on virus vaccines which succinctly describes the present status and future developments of over 17 human vaccines. The section on future prospects for vaccination covers administr-

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ation routes, live (including genetically attenuated strains), inactivated, subunit, recombinant, synthetic and antiidiotype vaccines. This is both an interesting and readable summary and, aided by well tabulated data, a useful reference work. It is intended as a status report, thus the sections on individual vaccines are, of necessity, short and succinct summaries and not in depth studies. Papillomaviruses are DNA viruses and, except for bovine types, are species specific. They replicate in epidermal cells during keratinization. The human types are of interest because as well as

industrial research and development and production laboratories, and (c) health care providers including policy makers. The incentives, disincentives and motivations for this triple complex are multiple and include such matters as resource allocation for research, economic incentives for vaccine development and production, vaccine-caused injury and liability and compensation issues, marketability and extent of vaccine use, public information and public acceptance, and the lack of precedent and strong orientation in medical practice, aside from paediatrics, to disease prevention by vaccination. The committee's report is exemplary in its analysis of problems and proposals for solving this multifactorial complex of barriers to innovation in vaccine development and supply. The Committee recognized the difficulty of maintaining any coordinated and continuing activity in vaccine development and use and recommended, as did previous committees, that a non-governmental or quasi-governmental National Vaccine Commission be established. This commission would report to the President and the Congress, and the objectives would be '(1) to advance the control of infectious disease by promoting the continued innovation, production, and use of vaccines, and (2) to ensure that this goal is achieved in a socially responsible and just manner'. One aspect of report is, in a sense, outdated by the recent enactment of the omnibus health package (S. 1744) that contains vaccine injury compensation reforms. The committee may take credit, in part at least, for bringing about this favourable development. The report should be considered required reading for anyone engaged in development or delivery of vaccines. Dr Jay Sanford and his committee, and study director Dr Roy Widdus can be justifiably proud of what they have wrought.

Maurice R. Hilleman being responsible for warts, and benign tumours (papillomas), they are also associated with genital tumours. The review very thoroughly covers all aspects of their role in human disease, their interaction with the body's immune surveillance system, and therapeutic and prophylactic aspects. Aleutian disease is caused by an autonomous and persistent parvovirus infection of mink and has serious economic consequences. This chapter summarizes recent data on the postimmune response to the infection and its effect on initiating the disease. The chapter on herpes virus latency and recurrence addresses a problem that is still not fully understood and is of great importance to the development of safe herpes simplex virus vaccines. The