The sleeping giant

Abstract

Overshadowed by AIDS, tuberculosis, and malaria, the tropical disease sleeping sickness has been wrongly neglected, a new book claims. Brian Greenwood reports

An unintended consequence of the effort to control AIDS, tuberculosis, and malaria has been relative neglect of other major tropical infectious diseases, such as schistosomiasis, leishmaniasis, and trypanosomiasis. Together these infections are responsible for nearly as many deaths as malaria causes. The efforts of advocacy groups and media attention have resulted in widespread recognition among the public of AIDS, tuberculosis, and malaria, but there is little awareness of the continuing presence of major parasitic infections such as African trypanosomiasis. Trypanosome infections in humans are called sleeping sickness, because in the terminal phases of the infection patients often become comatose, sleeping all the time. However, in earlier phases of the disease the patient may have many other neurological signs and mood disturbances.

Trypanosome infections are still important in large parts of sub-Saharan Africa, because of the direct effect on people of the West African (Gambian) or East African (Rhodesian) forms of sleeping sickness, both of which are 100% fatal unless treated effectively, and because trypanosome infections in cattle reduce agricultural productivity and hence contribute to poverty and susceptibility to other diseases. This message comes over clearly in The Fatal Sleep, whose author looks after patients with neurological diseases in Glasgow while also having close links through his laboratory work with veterinarians in Glasgow and Kenya whose primary interest is sleeping sickness.

Kennedy’s book about trypanosomiasis covers its key features in a way that makes it accessible to a general audience, mixing chapters of autobiography, travelogue, and biology. Although this format makes it interesting to general readers with little knowledge of Africa or trypanosomiasis, it has the disadvantage that parts of the book are rather superficial for readers who have some knowledge of either. For example, the first chapter contains a detailed description of the author’s medical school elective spent in Zambia; and some of his later descriptions of visits to Kenya and Uganda are examples of popular travel writing rather than popular science. His experience of research in East Africa comes primarily from short term visits; and some of his descriptions of Africa, such as those of driving on pot holed roads, are more likely to be of interest to tourists or short term visitors than to anyone with more experience of working in Africa, for whom pot holed roads are likely to be a part of everyday life.

But Kennedy has provided a comprehensive account of the history of sleeping sickness, the biology of the trypanosome and of its tsetse fly vector, and how the disease affects humans and animals. These accounts are clear, comprehensive, and free of jargon and should be easily understood by the interested general reader with little scientific background, although chapter six on the immunology of the infection may require some perseverance.

Treatment of human and animal trypanosomiasis, an area in which the author’s research group at Glasgow has made important contributions, is covered well. The fact that the mainstay of treatment of advanced sleeping sickness remains melarsoprol, which kills one in 20 of the patients who receive it, is forcibly made and illustrates the neglected development of new treatments for this condition, in humans or animals. Fortunately, some progress in this area has been made recently, as described in the book’s last chapter.

Has Kennedy missed any important scientific issues? Vaccination, not included in the index, might have been given more attention, as the general reader is likely to be familiar with recent major efforts to develop vaccines for malaria and HIV and may wonder why this is not the case for trypanosomiasis. More importantly, I do not think that the book conveys to the general reader the magnitude of the problem of sleeping sickness in humans in the first half of the 20th century, when epidemics of the disease had a similar impact as the current epidemic of HIV, or of more recent epidemics in war torn countries such as Angola, the Democratic Republic of the Congo, and Sudan. Describing a few patients in a Kenyan hospital and recounting the need to find a new research site in Uganda because of a lack of patients for research in Kenya will not impress readers who are aware of the scale of the problem of HIV, malaria, and tuberculosis in Africa. The advocacy component of the book would have been stronger for a description of one of these recent epidemics and its devastating effects on the community in which it occurred.

Kennedy is to be congratulated on writing a book for a general audience about an important but neglected tropical disease, and he has generously offered half his royalties to charities working to alleviate its results. However, the book would have been improved had it included more about sleeping sickness itself and less about the author’s travels.

The mainstay of treatment of advanced sleeping sickness remains melarsoprol, which kills 1 in 20 patients