Mosquitoes, especially those in Sub-Saharan Africa, may transmit malaria to humans.

James L. A. Webb, Jr
Professor, Colby College

Malaria is the oldest of the human infectious diseases. Over tens of thousands of years, as early humanity expanded in tropical Africa and across tropical Eurasia, malaria parasites took advantage of our human propensity to migrate and our social need to congregate.

Malaria traveled with infected hunters and adventurers across mountain ranges and deserts, and after the domestication of animals, malaria traveled more quickly, galloping across grasslands and plains. It became the principal disease burden of Eurasia as well as tropical Africa. And much, much later, thanks to the technological ingenuity of human beings, malaria sailed with infected passengers on shipboard across the oceans, rode the rails across the continents, and then flew aboard aircraft from one hemisphere to the other. It became a global disease.

Malaria has etched highly varied patterns into human history. In some times and places malaria has appeared as a seasonal affliction and in others as a year-round burden. It has been a debilitator of general populations and a killer that targets young children and non-immunes. For these reasons, our cultural assessments of malaria's significance have been highly diverse, and different societies have 'known' malaria in very different ways.

Malaria remains such a common disease that only imprecise estimates of its impacts are possible. The broad and inexact contours, however, tell the big story.

An estimated 2.4 billion people are at risk of infection. An estimated 300 to 500 million people suffer bouts of the disease each year. Perhaps 90 percent of these occur in tropical Africa. Malaria kills somewhere between 1.1 and 2.7 million people per year. Of these deaths, approximately one million are children in tropical Africa between the ages of eighteen months and five years.

In the past, malaria was erratically distributed over humid and arid landscapes, along coast and in forest, across cityscapes and rural landscapes, in sub-arctic, temperate, subtropical, and tropical zones. Over the course of the twentieth century, however, malaria lost its hold on the northern temperate world, and across those liberated landscapes cultural knowledge about malaria, too, slipped away.

Today, malaria is an almost forgotten disease in much of the western world. What was once a global affliction-the primary public health disaster in the United States of America during the nineteenth century, the principal disease of British India, the core challenge of the modernizing Italian state in the twentieth century, and the elusive target of the first global eradication campaign of the World Health Organization-is now broadly regarded as a 'tropical disease.'

Humanity's Burden traces the movements of malarial infections – in deep time from tropical Africa into Eurasia; later from Afro-Eurasia to the Americas; and relatively recently the retreat of malaria from the temperate zones to the tropics. It sketches the profound impacts of malaria on the evolution of human history and shows that malaria has affected virtually the entire range of human societies-from gatherers and yam cultivators in tropical Africa with low levels of technological sophistication through a range of subjects and citizens in contemporary states.

Editor's Note: James L.A. Webb, Jr. is Professor of history at Colby College, where he teaches courses in world history, African history, ecological history, and historical epidemiology. He is currently writing a book on the history of malarial infections and interventions in modern Africa. He is the author of Humanity's Burden: A Global History of Malaria (Cambridge University Press, 2009), Tropical Pioneers: Human Agency and Ecological Change in the Highlands of Sri Lanka, 1800-1900 (Ohio University Press, 2002), and Desert Frontier: Ecological and Economic Change along the Western Sahel, 1600-1850 (University of Wisconsin Press, 1995).