The Fever Trail: The Hunt for the Cure for Malaria/The Fever Trail: In Search of the Cure for Malaria

  • Mark Honigsbaum
Macmillan: 2001. 352 pp. £18.99/ Farrar Straus Giroux: 2002. $25

If ever there were a story that illustrates the need for high-quality taxonomy, this is it. The quest for a cure for malaria has occupied many people for many years — and it is still going on, both in the field and in the laboratory. Mark Honigsbaum has brought the story of the search for the first remedy, 'Jesuit's bark' — now known as quinine — to life in an entertaining and readable way, all the while reminding us that malaria is the world's third-biggest killer behind dysentery and tuberculosis.

Some parasitologists estimate that half of the people ever to have lived on Earth have succumbed to this deadly disease. Malaria decimated military might in battle after battle during the eighteenth and early nineteenth centuries, from Britain's attempts to take Spain's New World colonies to critical confrontations with Napoleon in Belgium, where forces were halved through mortality and morbidity. The numbers are hardly less frightening today: there are between 300 million and 500 million cases, and 1.5 million to 2.7 million deaths, each year from malaria, most of them children.

Most of the book is devoted to the travels and travails of the European explorers Richard Spruce, Charles Ledger and Clements Markham. Their stories are woven in and out of the social issues and political climate of Europe in the nineteenth century. Spruce and Ledger in particular were intrepid men, braving much hardship in the search for botanical novelty.

Miracle cure: the Cinchona tree was found to yield the antimalarial drug quinine — but it was better to keep mosquitoes at bay in the first place (top).

They both became involved in the search for the miracle malaria cure Jesuit's bark, the bark of the Cinchona tree, when they were already in South America. Spruce was collecting plants and Ledger was setting up businesses. Botanists in the Andes observed that the forests were being stripped of trees, this potentially renewable resource being extracted rather than used sustainably. Spanish control over the Cinchona regions, on the eastern slopes of the Andes, made supplies of the tree limited and expensive. Coupled with the British and Dutch colonization of the tropical regions of Asia, the climate was ripe for some ex situ conservation.

Markham and others reasoned that it was better to save this miracle cure by transplanting it into regions where it could be cultivated for the use of all — an argument that surfaces again and again in relation to the destruction of natural resources, even today. The quest was bedevilled by questions of how to tell the species of Cinchona apart and which one was the most effective cure — indeed, the complex taxonomy of Cinchona was not stabilized until the 1990s. There was also a need for secrecy, because the export of Cinchona seeds or bark was illegal, and the Spanish colonies (and the republics that followed) had a monopoly on the raw material for the drug. The story of the theft of Cinchona has many parallels to the situation today. To whom do cures 'belong' — the people in the country where the plant grows, or those who discovered the use of the plant? And should we develop the drugs for profit or for philanthropy?

The story that Honigsbaum does not tell is that of the mosquito itself. Only some species of Anopheles transmit malaria, and their taxonomy is as complicated as that of Cinchona. Controlling the disease by destroying the mosquitoes that transmit it depends on first identifying them, a taxonomic tale not told in this book but perhaps the subject for another. Another problem was that distinguished medical men dismissed as fantastic the idea that mosquitoes transmit a filarial parasite that causes malaria — only dogged perseverance showed how wrong they were.

The development of synthetic drugs such as chloroquine and quinacrine made dependence on Cinchona bark a thing of the past, and an understanding of how the disease worked made control seem possible. But here this meant confronting the reality of nature. Malaria parasites evolve drug resistance, mosquitoes evolve pesticide resistance, and a vaccine seems as far away as ever, despite decades of research. The depressing observation by one of Honigsbaum's sources that “pharmaceutical companies are simply not interested in developing drugs for people who cannot afford shoes” shows that the tension between profit and philanthropy is still with us, just as it was in the hunt for Cinchona in the nineteenth century. But global warming and the concomitant spread of malaria to Europe and the United States may change all that. Malaria may become a disease of people who have shoes, and the impetus for drug and vaccine development may acquire new urgency.

One of the great riddles of malaria is how Cinchona's properties came to be discovered at all. Malaria did not exist in the New World until the Spanish and Portuguese arrived in the sixteenth century. Malaria is an Old World disease that was initially cured using a New World plant. Honigsbaum doesn't answer this conundrum, but he has written a fascinating book full of thought-provoking ideas. The seemingly arcane and out-of-date story of the hunt for a malaria cure brings home the timely message that knowledge of the world around us, from taxonomy, ecology and medicine, remains critical to our capacity for survival.