Biology, Diseases, and Economics: An Epidemiological History of Slavery in the American South

The economic history of antebellum southern slavery has been and is the subject of ongoing debates among scholars. The literature includes assessments about the efficiency of slavery as well as about the adequacy of slave living standards and diets. Yet this literature under appreciates the important biologic and historical role that parasitic diseases played in the history of slavery. Recognizing the role of parasitic diseases calls into question some prevailing interpretations of slavery. Lacking direct evidence on slave diets, scholars turned to anthropometric evidence as proxies for the living standards of slaves, leading to the prevailing view that adult slaves were given adequate sustenance, but slave infants and children were severely malnourished. We argue it was not slave diets, but the combination of the plantation system and diseases that caused abnormally small slave children. The diseases that concern us, primarily hookworm and malaria, affected slaves ('blacks') and free labor ('whites') differently. Many slaves were concentrated on large plantations with infants and younger children crowded into 'nurseries.' This system allowed the maintenance and spread of diseases that adversely affected younger slaves. Southern white children however were less likely to be raised in conditions so conductive to parasitic diseases. The disease ecology of the antebellum South has implications for the prevailing view that slavery was more efficient than free labor. Biologic evidence indicates that people of tropical West African ancestry are more resilient to the effects of hookworm and malaria than European descendents. Thus when whites did contract these diseases, they were more afflicted than blacks. When slaves entered the adult work force they were taken from disease breeding grounds (slave nurseries) and sent into relatively (for blacks) healthy fields, while whites that went into the fields found a disease environment that was typically worse than that of their childhood. If black adults were more productive than were white adults because of a greater resilience to parasitic diseases, then part of any measured difference in productivity between slave and free farms should be attributed to the disease resistance of African descendents, rather than to any inherent efficiencies of slavery.