THE WELLCOME TRUST ILLUSTRATED HISTORY OF TROPICAL DISEASES Edited by F. E. G. Cox Wellcome Trust, 452pp, Pounds 35.00 ISBN - 1869835 86 7

As a scientific speciality, tropical medicine is barely 100 years old. In August 1897 Ronald Ross made the momentous discovery that malaria, the most fatal and prevalent of all diseases identified with the tropics, was transmitted by mosquitoes, and in 1898 Patrick Manson, Ross's mentor and widely regarded as the "father of tropical medicine", published a manual of tropical diseases, now in its 20th edition, which authoritatively defined the new discipline. The London and Liverpool schools of tropical medicine came into being shortly afterwards and were quickly followed by many other institutes, associations and journals around the globe. And yet a century after Manson the status and identity of tropical medicine remains in many respects unclear. Why should there be a special medicine for the tropics alone? Are the diseases of the tropics significantly different from those of temperate countries, or has tropical medicine, the creation of now largely defunct imperial powers, itself become an anachronism?

Like Manson, who admitted that the term "tropical diseases" was "more convenient than accurate", F. E. G. Cox in the preface to this book is forced to acknowledge that the problem of definition is far from easy: "Some diseases", he remarks, "occur only in the tropics, others mainly in the tropics and yet others equally in the tropics and elsewhere." In 1898 Manson identified malaria, sleeping sickness, dysentery, bilharzia, leprosy, plague, cholera, yaws, yellow fever, and beri-beri among the leading diseases of the tropics. Cox and his colleagues have augmented this list to cover 41 diseases (or disease complexes) but have omitted a number, such as tuberculosis, measles, poliomyelitis and smallpox, which might be considered equally important.

If mortality were the criterion, it would appear arbitrary to include rabies (in an article which makes no specific reference to the tropics) and omit influenza which devastated many tropical territories in 1918/19, though it could be argued that through the contribution it made to medical research rabies was ultimately of greater significance. The editor also decided, perhaps more questionably, to omit HIV and Aids on the grounds that "this was neither the time nor the place to cover this important infection which has taken on particular tropical connotations", though in surveying the history of cryptosporidiosis and donovanosis contributors inevitably refer to their recent connection with HIV and Aids. In a volume intended for non-specialist readers, the issue of what is or is not a tropical disease remains troublingly elusive. Geography and climate are clearly not dependable guides. Although the volume ranges widely before and since the formal establishment of tropical medicine (and deploys recent research to explain the complexity of diseases that bear deceptively simple labels like cholera), the precedents set by Manson remain strikingly important, as does his own contribution to medical research.

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As Cox and other contributors acknowledge, many of what are now thought of as tropical diseases, like leprosy and typhoid, have only become so relatively recently as a result of their effective eradication in other parts of the world. They remain tropical by lingering on as diseases of poverty and poor sanitation. But no less strikingly, in a volume that is (despite its title) as much about medicine as disease, tropical medicine emerges as a speciality built around its "heroes", the individuals whose observations and investigations sustained the Mansonian vision of a distinctive field of scientific activity.

It is not surprising, then, that this book has something of a celebratory air. This is not intended as a textbook of tropical diseases, but is "largely about those who devoted their lives to tropical diseases" and in some cases died in pursuit of that knowledge. The illustrations, many of them drawn from the Wellcome Trust's own collection, reflect the personal involvement of past and present researchers. All the contributors are, or have been, specialists in tropical medicine and their essays profit from this expertise and commitment without losing sight of the need to communicate with a wider, nonspecialist audience.

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The absence of professional historians is, however, equally striking, and the value of accounts written by medical specialists needs to be set against the neglect of work by historians of medicine, including the recent rapid growth of work specifically on medicine in the tropics. There is, moreover, no attempt, beyond a brief introduction, to bring the essays together in a systematic overview, though it is a tribute to their individual richness that other histories than those specifically addressed by the contributors also emerge. Thus there is a history here of European discovery, written in encounters with diseases new to Europe but ancient in their own lands. There is a history of isolated European medical observers in the outposts of trade and empire - Winterbottom in West Africa, Ballingall in India, Manson himself in China - and their hitherto underacknowledged contribution to the development of metropolitan science. There is a history of Brazilian, Japanese and Indian researchers, working on subjects as diverse as trypanosomiasis, leishmaniasis, bilharzia and malnutrition, and showing how the discipline rapidly grew beyond its European origins to become a medicine of the tropical and non-European world.

There is also a striking absence, for women are largely missing from these essays. Cicely Williams, remembered for her investigation of kwashiorkor, is one of only three or four women mentioned alongside many hundreds of men, despite the scores of women doctors who worked in the tropics and were responsible for directing medicine there towards greater engagement with the health of women and children and with conditions associated with reproduction and malnutrition.

This book might best be understood as an exercise in self-appraisal, an end-of-century progress report, and as such it strikes a judicious note. Some diseases, like yaws, which once defined the horrors implicit in the tropics, face almost imminent extinction, while others, like melioidosis, reflect the rise to medical prominence and public consciousness of pathogens and parasites unknown or little regarded in Manson's day. Judicious, too, is the awareness shown in many essays that it is hunger, poverty, ignorance or a want of political will that allows conditions to survive that might otherwise have vanished long ago.

For all its limitations, this is a valuable source and commentary for anyone interested in the history and present state of those diseases that have come to be identified with the tropical world. And yet one is left wondering how far the idea of the tropics, and hence of tropical medicine, will survive into the coming century. Some countries which happen to be located in the tropics may prosper and grow healthier, while others elsewhere may suffer all the hazards to health associated with economic decline and political disintegration. A century after Manson, the Illustrated History provides a fitting retrospective.

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David Arnold is professor of the history of South Asia, School of Oriental and African Studies, London University.