James L. A. Webb

Historical epidemiology and infectious disease processes in Africa

This article outlines the historical development in African studies of the sub-discipline of historical epidemiology and the contemporary challenges of understanding infectious disease processes that require integrating biomedical and historical knowledge. It suggests that Africanist historians can play a significant role in collaborative and multidisciplinary research in this field by exploring the histories of disease processes and interventions, and thereby contributing to improvements in public health practice and outcomes.

The Horse and Slave Trade Between the Western Sahara and Senegambia

Following the late fifteenth- and sixteenth-century cavalry revolution in Senegambia, the horse and slave trade became a major sector of the desert-edge political economy. Black African states imported horses from North Africa and the western Sahara in exchange for slaves. Over time, under conditions of increasing aridity, the zone of desert horse-breeding was pushed south, and through crossbreeding with the small disease-resistant indigenous horses of the savanna, new breeds were created. Although the savanna remained an epidemiologically hostile environment for the larger and more desirable horses bred in North Africa, in the high desert and along the desert fringe, Black African states continued to import horses in exchange for slaves into the period of French colonial rule. The evidence assembled on the horse trade into northern Senegambia raises the difficult issue of the relative quantitative importance of the Atlantic and Saharan/North African slave trades and calls into question the assumption that the Atlantic slave trade was the larger of the two. Most available evidence concerns the Wolof kingdoms of Waalo and Kajoor. It suggests that the volume of slaves exported north into the desert from Waalo in the late seventeenth century was probably at least ten times as great as the volume of slaves exported into the Atlantic slave trade. For both Waalo and Kajoor, this ratio declined during the first half of the eighteenth century as slave exports into the Atlantic markets increased. The second half of the eighteenth century saw an increase in predatory raiding from the desert which produced an additional flow of north-bound slaves. For Waalo and Kajoor – and probably for the other Black African states of northern Senegambia – the flow of slaves north to Saharan and North African markets probably remained the larger of the two export volumes over the eighteenth century. This northward flow of slaves continued strong after the abolition of the Atlantic slave trade and was only shut down with the imposition of French colonial authority.

Aedes aegypti suppression in the Americas: historical perspectives

556 www.thelancet.com Vol 388 August 6, 2016 Today populations in the Americas are under increasing threat from the dengue, chikungunya, and Zika viruses, spread by the Aedes aegypti mosquito. In earlier centuries, the same mosquito spread the deadly haemorrhagic viral infection known as yellow fever. Rigorously organised vector control programmes in the 20th century, however, ended the urban cycle of yellow fever in the Americas. This historic public health success has relevance for the current public health crisis. The A aegypti mosquito arrived in the Americas on the slave ships that transported African captives to the Americas, as did the yellow fever virus. The fi rst epidemic of yellow fever— with its signature symptom of black vomit—exploded in the mid-17th century in the Caribbean. Thereafter, A aegypti sporadically ignited haemorrhagic yellow fever epidemics that ravaged military encampments and coastal cities. In the late 19th century, the Cuban physician Carlos Finlay proposed that a mosquito was the vector for yellow fever, and at the turn of the 20th century, the US Army’s team of medical investigators in Cuba, led by Walter Reed, discovered that A aegypti was indeed the culprit. It was a domesticated mosquito that bred in man-made containers that capture rainwater. In 1901, the US military began rigorous campaigns to destroy its breeding sites in dense urban areas that were thought to be “seedbeds” of infection. The success of the early eff orts was remarkable. Yellow fever was eliminated from Havana and other Cuban port cities and the Panama Canal Zone in the fi rst decade of the 20th century. Others took inspiration. In 1903, Oswaldo Cruz, the Brazilian Director-General of Public Health, began a campaign in Rio de Janeiro that, by 1909, had reduced yellow fever deaths there to zero. In 1916, the Rockefeller Foundation created a Yellow Fever Commission, which determined that Guayaquil in Ecuador was a centre of endemic infection, and eliminated yellow fever deaths there within 2 years. Some gains, however, proved impermanent. In 1928, a yellow fever outbreak in Rio de Janeiro and in a few Brazilian towns and settlements outside of the main urban areas forced a reassessment of vector control strategy. Beginning in 1930, with fi nancial support from the Rockefeller Foundation, the Brazilian dictator Getúlio Vargas authorised a military-style programme of larval source reduction that compelled city and town dwellers to destroy breeding sites on their properties, imposed fi nes for non-compliance, and required the post-mortem extraction of liver tissue samples from individuals whose deaths were suspected to have been caused by yellow fever, in an eff ort to better understand the spatial epidemiology of the outbreaks. Fred Soper, a Rockefeller Foundation health offi cial, spearheaded the Brazilian initiative, which focused on the suppression of A aegypti in urban areas and eliminated the mosquito in several cities. Soper and his colleagues discovered, however, that there was a primate reservoir of the virus in the South American rainforests transmitted by a diff erent genus of mosquito. Although they realised that they could not stop the sylvatic cycle, this did not stem their commitment to vector control. They expanded their eff orts and eliminated A aegypti throughout most of Brazil, and their major challenge became the prevention of the introduction of the mosquito from neighbouring states. Soper and his team reached this milestone before the era of synthetic residual insecticides. They secured the gains by administering the Rockefeller Foundation’s 17D yellow fever vaccine to urban populations. In 1938–39, Soper and his co-workers undertook a separate vector control campaign to suppress a non-domesticated malaria mosquito Anopheles gambiae sensu lato (Anopheles arabiensis) which had been introduced into northeastern Brazil from west Africa. They eliminated it. During World War 2, Soper helped to launch an elimination project in Egypt against an A gambiae sensu lato mosquito introduced from subSaharan Africa and it achieved full success by 1945. In the immediate post-war era, DDT became available for larval suppression. In 1947, Soper was elected Director of the Pan-American Sanitary Bureau, and the member states agreed to eliminate A aegypti—even though there had only been one urban outbreak of yellow fever in the Americas in the preceding 15 years. In 1955, the World Health Assembly ratifi ed a programme for global malaria eradication that was based upon the use of synthetic residual insecticides. By 1964, the malaria programmes had reduced malarial infections to small numbers. In the same year, a full victory against A aegypti and urban yellow fever seemed at hand. Brazil and most other The art of medicine Aedes aegypti suppression in the Americas: historical perspectives

Climate, Ecology, and Infectious Human Disease

This chapter provides an historical overview of the relationship between climate change, ecological change, and infectious human disease. It argues that the forces of climate have long been determinative in establishing the ecological parameters within which human beings and the pathogens that have caused infectious disease have coexisted. Our best understandings of the interactions of climate, ecology, and infectious human disease are based on the integration of perspectives from the biological, social, and historical sciences.

The making of a tropical disease: A short history of malaria

Randall Packard is the current director of the Institute for the History of Medicine at Johns Hopkins University. He began his career as an historian of Africa and wrote a seminal book on the history of tuberculosis in South Africa that has attained the status of a classic in the field (Packard 1989). He has gone on to have a distinguished career as an historian of international public health and for the past 20 years or so has written compellingly about malaria. Malaria has an extraordinarily complicated aetiology, because it is caused by any one of four different parasites or a combination thereof. The parasites are borne by mosquitoes that take blood meals from human beings. There are several scores of different anopheline mosquitoes that can host the parasites, and the different mosquito species have different ecological behaviours. For these reasons, ‘malaria’ rather than being a single disease is actually a complex, shifting mosaic of infections. Human beings take the parasites with them when they migrate, and by the middle of the second millennium CE malaria had become a global disease. The ecological complexity of the disease allows for a variety of different approaches to the ‘causes’ of malaria. In this impressive synthesis of malaria history with a broad political economy approach, Packard focuses on the social, political and economic causes of the disease. This approach serves as a critical counterargument to what he refers to as the ‘biological model’ of malaria that emerged in the last decades of the twentieth century and that has been the intellectual undergirding of recent efforts to control the disease. He hopes to broaden the conceptual framework of malaria policy-makers. Packard characterises his main point as a simple one: ‘ . . . the array of biomedical weapons mobilised in the war against malaria needs to be joined with efforts to improve the social and economic conditions that drive the epidemiology of the disease’ (p. xvii). Packard begins his book with reflections on his early Peace Corps experiences in Uganda. There, he became intimately aware of the social, political and economic constraints that limited villagers’ access to malaria treatments and came face to face with the egregious and unnecessary loss of life to malaria. This sensitivity to malaria realities and commitment to drawing policy-makers’ attention to the plight of the malaria-stricken poor is an integral dimension of Packard’s book. The making of a tropical disease is organised around a series of case studies, with multiple variations, that illustrate his theme that history provides the necessary context to understand the contours of malaria disease processes. He stresses: ‘In order to understand and to respond effectively to the persistence of malaria as a global health problem, it is critical to view the disease as part of a wider historical Global Public Health Vol. 5, No. 4, July 2010, 441 443

Slavery and Colonial Rule in French West Africa

1. Slavery in the Western Sudan 2. Abolition and retreat: Senegal, 1848-1876 3. Slavery, slave-trading and social revolution 4. Senegal after Briere 5. Conquest of the Sudan: Desbordes to Archinard 6. Senegal in the 1890s 7. The end of the conquest 8. The imposition of metropolitan priorities on slavery 9. With smoke and mirrors: slavery and the conquest of Guinea 10. The Banamba exodus 11. French fears and the limits to an emancipation policy 12. Looking for the tracks: how they did it 13. After the war: renegotiating social relations 14. A question of honour.

Desert frontier: ecological and economic change along the Western Sahel, 1600-1850

A study of the ecological and economic impact of desertification along the southern edge of the western Sahara. A climatological trend toward increasing aridity has forced the desert 300 kilometers to the south, transforming ethnic identities and ways of life along the Western Sahel.

The Economies of Africa and Asia in the Inter-War Depression

A detailed assessment of the impact of the depression on the economies of Africa and Asia. This book should be of interest to advanced students and teachers of modern economic history, and of the economics of Africa and Asia.