Africa in the Time of Cholera: A History of Pandemics from 1817 to the Present by Myron Echenberg (review)

Echenberg has nicely summarized the history of cholera for the well-known Africa Studies Series, organizing his work by combining the first six pandemics—1817-1947—for the initial half of this book and then considering the seventh pandemic—1947 to the present—as the last half of the book. This is an apt division as the present pandemic is largely caused by the El Tor variant of the gram-negative, motile bacillus, Vibrio cholerae 01, which became dominant in the world in 1961, and is less virulent than its predecessors. To understand cholera, one must realize that there are scores of species of the Vibrio genus living in warm estuaries and brackish waters in the world. Though several species can cause diarrhea in humans, only V. cholerae has the gene that produces the complex protein toxin which causes the intestine to release large quantities of fluid as "rice water stool"—up to two liters an hour in adults—often leading to dehydration and death in hours.

Summarizing the first half of this book, it can be observed that in the nineteenth century, cholera spread repeatedly from its natural habitat in the estuaries of Bengal to the Middle East and then to Europe and the Americas. Africa—the north and then the south—saw an increasing number of epidemics during this time as well. Echenberg describes the slow and painful process of finding the cause and then effective treatment of cholera during the first six pandemics. During a cholera epidemic in Florence in 1854, Filippo Pacini found the bacillus by microscopy, named it V. cholerae, but died in obscurity in 1883, just months before the famous bacteriologist, Robert Koch, found the same bacillus in specimens from epidemics in Alexandria and Calcutta. John Snow stopped an epidemic in London in 1854 by, famously, taking away the handle of the Broad Street pump. Ever so slowly, it became obvious that cholera was spread by drinking water contaminated with human feces. From 1865 to 1874, James Christie, then resident in Zanzibar, worked out the epidemiology of cholera in published studies, relevant even to this day. As to treatment, it took a long time for intravenous fluid repletion therapy to gain acceptance and widespread use and then many years until the optimal chemical constitution of intravenous fluids was determined. From 1851 until 1938, there were fourteen International Sanitary Conferences held in various venues, dealing with several epidemic infectious diseases but, increasingly, with cholera. It might be observed that prevention and treatment improved with each of the first six pandemics, but that improvement was modest.

While case and mortality counts of particular African cholera epidemics in the past sixty years or so might be suspect in their specificity, they nonetheless define cholera as we presently know it. Cholera in this century is an African problem as Echenberg shows in the second half of this book. He identifies four phases since 1971 and shows a generally declining case fatality rate during this period in sub-Saharan Africa, now averaging 2.5 percent for the years 2006 through 2009. He notes that Africa had two hundred and thirty-four thousand of the world's two hundred and thirty-seven thousand cholera cases in 2006, nearly 99 percent. Focusing on the large fresh water lakes of Africa, he suggests that warm, brackish water in Lake Chad, the Lake Tanganyika Basin, and the Malawi Lake Basin are now likely habitats for the El Tor variant of V. cholerae.Wars and thousands of refugees in search of water in The Democratic Republic of the Congo, Mozambique, and Rwanda have led to cholera epidemics. Poor management of water resources and misdirected international aid programs are cited in Senegal, South Africa, and Angola as promoting cholera epidemics. Finally, the once-prosperous Zimbabwe...