In Our Blood

Most of us think of malaria, if we think of it at all, as an unavoidable fact of life, a health hazard that plagues people in equatorial regions, as consistent and predictable as the sweltering tropical climate. Historian James L.A. Webb Jr., in this wide-ranging and compelling book, shows that humans and malaria have a long, evolving, and fascinating relationship, with people—from the time of the earliest hominids to the present day—playing host to the mosquito-borne parasite that has significantly shaped the way our species has developed around the world.

What might seem a daunting task—chronicling the role of malaria in world history—is accomplished through an accessible narrative in which Webb weaves history and science, epidemiology and health policy, archaeology and genetics. What emerges is an interdisciplinary big-picture look at a force that has had profound effects on our species but is usually viewed through a narrow lens.

The story begins in prehistoric tropical Africa. It explores a model that has human populations growing partly, the theory goes, because of a genetic mutation that made some people immune to a prevalent type of malaria. Later, cultivation of forest crops, including yams known to increase resistance to malaria, affected where and how human civilization developed.

Human migrants who left Africa for Eurasia left behind many of the tropical insects and animals that spread myriad diseases among humans, Webb writes.

“However, they could not flee easily from the malarial infections. They carried these infections in their bloodstreams, and in a spate of intense misfortune, as the migrants rambled through the wilds of Afro-Eurasia, they encountered the never-ending hum of Anopheles mosquito species that could play host to malaria parasites.”

On to the Americas, where malaria may have been spread by Spanish conquerors, and where the Caribbean basin proved to be “a lethal environment for non-immunes.” When the British invaded the island of Saint Domingue in 1794 to suppress a revolt by African slaves, an estimated 100,000 troops died—of malaria. The same fate befell the French troops in Haiti, a country created by rebels supported by epidemiology.

Webb moves adroitly through history, considering wars of the 19th century (a major reason for malaria’s spread during that period), the use of quinine (and global trade in the tree bark from which it was first derived), anti-mosquito campaigns after World War II, and the recent resurgence of malaria in Africa, where the saga began. Why the resurgence? One factor, Webb reports, may be the growing of hybrid maize, the pollen of which is a boon to mosquito larvae.

It appears that malaria’s role in human development is long-standing and ongoing. In this book, Webb gives the disease its deserved place in history.