Collaborative Research: The Differential Impact of Parasitic Diseases on Agricultural Productivity of Blacks and Whites in the Early Twentieth-Century South

这个项目考察了寄生虫病对20世纪初美国南部不同祖先遗产的人口生产力的影响。这项研究具有历史意义，因为它量化了地方性寄生虫病与两个具有历史重要性的群体--非洲裔美国人(黑人)和欧洲裔美国人(白人)--的经济福祉之间的关系。该项目有助于解释美国南方的经济发展，并解决有关19世纪南方奴隶制生产力的问题。这项研究的重点是疾病的地理特殊性以及黑人和白人对特定地方性疾病，主要是寄生性钩虫和疟疾的不同生物易感性。这项研究从洛克菲勒档案中心收集了20世纪初南部11个州所有可用县的寄生虫病流行情况的档案数据。该项目使用现有的疾病流行率和各种气候、地理、病因和其他与疾病有关的数据来估计(归因于)那些缺乏明确疾病数据的南部县的疾病流行率。这项研究使用了南方968个县的显性和归因性疾病患病率以及农业投入和产出数据，以估计黑人和白人农业劳动力在县级经济生产率(农业产出)方面的差异。对其他相关变量的生产力控制的计量经济学估计，并纠正了各种统计问题。该项目更广泛的意义是，它为估计当今世界寄生虫病的影响提供了数据。地方性钩虫和疟疾在解释20世纪早期南方黑人和白人农业劳动力的经济生产力方面所起的作用，有助于理解这些疾病在今天的经济影响。钩虫目前感染了世界人口的20%至33%；疟疾感染了3亿至5亿人，每年导致200万至300万人死亡。这些疾病对经济的影响还不是很准确，但20世纪初的估计表明，钩虫使劳动生产率从20%下降到70%。疟疾的经济影响目前正在研究之中。仅对钩虫影响的假设性但似是而非的估计说明了这些疾病可能造成的损失。使用20%的钩虫感染率意味着全球约有12亿人受到感染。如果钩虫感染人均收入相当于800美元的人(世界上最贫穷国家的人)，年生产率仅下降15%，仅钩虫造成的经济损失每年就达1440亿美元。以4%的利率计算，这意味着世界上最贫穷的人永久减少了3.6万亿美元的财富。这种计算是不精确的。但它表明，在许多发展中国家，控制地方性寄生虫病可能是与贫困作斗争的有效途径。该项目对钩虫和疟疾造成的经济生产力损失的估计为估计这些疾病的同期影响建立了更精确的界限。

This project examines the impact of parasitic diseases on the productivity of populations of different ancestral heritages in the early 20th-century American South. The research has historical significance because it quantifies the relationship between endemic parasitic diseases and the economic well-being of two historically important populations, African-Americans (blacks) and European-Americans (whites). The project helps explain the economic development of the American South and address questions concerning the productivity of 19th-century southern slavery. The research focuses on the geographical distinctiveness of diseases and the differential biological susceptibilities of blacks and whites to particular endemic diseases, primarily to parasitic hookworm and malaria. The research gathers archival data from the Rockefeller Archive Center on the prevalence of parasitic diseases in the early 20th-century for all available counties for eleven southern states. The project uses the available disease prevalence rates with various climatic, geographical, etiological factors, and other disease-related data to estimate (impute) disease prevalence rates for those southern counties that lack explicit disease data. The research employs the explicit and imputed disease prevalence rates along with agricultural input and output data for 968 southern counties to estimate differences in county-level economic productivity (agricultural output) between black and white agricultural labor. The econometric estimations of productivity control for other pertinent variables and correct for various statistical concerns.The broader significance of the project is that it provides data for estimating the impact of parasitic diseases in the world today. The role of endemic hookworm and malaria in explaining early 20th-century economic productivity of southern black and white agricultural labor assists in understanding the economic impact of these diseases today. Hookworm currently infects between 20 and 33 percent of the world's population; malaria infects 300 to 500 million people and kills 2 to 3 million per year. The economic impact of these diseases is not known with much precision, but early 20th-century estimates suggest hookworm reduced labor productivity from 20 to 70 percent. Malaria's economic impact is just now being studied. A hypothetical but plausible estimate for the impact of hookworm alone illustrates the possible magnitude of the costs of these diseases. Using the 20 percent hookworm infection rate means that about 1.2 billion people worldwide are infected. If hookworm infects people with a per capita income equivalent of $800 U. S. dollars (people in the world's poorest nations) and reduces annual productivity just 15 percent, the economic losses due to hookworm alone are $144 billion per year. Capitalized at an interest rate of 4 percent, this represents a permanent wealth reduction of $3.6 trillion for the world's poorest peoples. This calculation is imprecise. But it suggests that throughout much of the developing world the control of endemic parasitic diseases may be an effective way to combat poverty. This project's estimation of the lost economic productivity attributable to hookworm and malaria establishes more precise boundaries for estimating the contemporaneous effects of these diseases.