This study evaluates the economic consequences of the successful eradication of hookworm disease from the American South. The hookworm-eradication campaign (c. 1910) began soon after (i) the discovery that a variety of health problems among Southerners could be attributed to the disease and (ii) the donation by John D. Rockefeller of a substantial sum to the effort. The Rockefeller Sanitary Commission (RSC) surveyed infection rates in the affected areas (eleven southern states) and found that an average of forty percent of school-aged children were infected with hookworm. The RSC then sponsored treatment and education campaigns across the region. Follow-up studies indicate that this campaign substantially reduced hookworm disease almost immediately. The sudden introduction of this treatment combines with the cross-area differences in pre-treatment infection rates to form the basis of the identification strategy. Areas with higher levels of hookworm infection prior to the RSC experienced greater increases in school enrollment, attendance, and literacy after the intervention. This result is robust to controlling for a variety of alternative factors, including differential trends across areas, changing crop prices, shifts in certain educational and health policies, and the effect of malaria eradication. No significant contemporaneous results are found for adults, who should have benefited less from the intervention owing to their substantially lower (prior) infection rates. A long-term follow-up of affected cohorts indicates a substantial gain in income that coincided with exposure to hookworm eradication. I also find evidence that eradication increased the return to schooling.

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Disease and Development: Evidence from Hookworm Eradication in the American South

This study uses the malaria-eradication campaigns in the United States (circa 1920), and in Brazil, Colombia and Mexico (circa 1955) to measure how much childhood exposure to malaria depresses labor productivity The campaigns began because of advances in health technology, which mitigates concerns about reverse causality Malarious areas saw large drops in the disease thereafter Relative to non-malarious areas, cohorts born after eradication had higher income as adults than the preceding generation These cross-cohort changes coincided with childhood exposure to the campaigns rather than to pre-existing trends Estimates suggest a substantial, though not predominant, role for malaria in explaining cross-region differences in income

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Malaria Eradication in the Americas: A Retrospective Analysis of Childhood Exposure

Publisher Summary This chapter discusses interaction of helminths and their hosts within the alimentary canal and, especially the stomach and intestines. Many such parasites live in the gastro-intestinal canal while others penetrate into the wall of the canal and a few invade organs, such as the liver and pancreas. The dynamic relationship between parasite and host is clearly shown and a good example set for future researchers. First, there is a study of the parasite–host interface, including the various kinds of organs of attachment, the varied nature of the lumen and the mucosa of the gastrointestinal canal, the nature of adhesion, and absorptive surfaces of the helminth and the host. The chapter describes the ecology of helminth site selection by trematodes, cestodes, and nematodes and matters concerning concurrent infections, transplantation, and migration. The chemical and physical characteristics of the intestinal lumen ionic and osmotic characters, microbial ecology, enzymes, bile acids and dietary fats, nutritive gradients, and matters of luminal homeostasis are discussed. The functional gradients in the gastrointestinal tract, bearing on the absorption of electrolytes and nonelectrolytes, water absorption, and malabsorption are also discussed.

Ecological and Physiological Aspects of Helminth-Host Interactions in the Mammalian Gastrointestinal Canal

Frequency of attendance at religious services and cigarette smoking in American women and men: the Third National Health and Nutrition Examination Survey.

The hemoflagellates, Trypanosoma spp. and Leishmania spp., are causal agents of a number of parasitic diseases having a major impact on humans and domestic animals over vast areas of the globe. Among the diseases are some of the most pernicious and deadly of human afflictions: African sleeping sickness, Chagas' disease, kala-azar, and Oriental sore. The organisms have complex, pleomorphic life cycles typically involving a vertebrate and an invertebrate host, the latter serving as a vector. In the vertebrate host, they are primarily blood and tissue parasites. In their transition from one host to another, the hemoflagellates undergo morphological, physiological, and biochemical changes that facilitate their growth and subsequent transmission. A major goal in the study of the hemoflagellates has been the cultivation in vitro of both vertebrate and invertebrate stages of the organisms. The first types of media used in their cultivation, and still useful for establishment of cultures, were undefined and contained a complex of ingredients. These gave way to semidefined formulations which included tissue culture media as a base and, as a next step, addition of tissue culture cells as a feeder layer to promote parasite growth. More recently developed media are completely defined, having replaced the feeder cells with various supplements. Serum, a sometimes-variable component of the media, can be replaced by various serum substitutes. This review focuses on the hemoflagellates that infect humans, describing stages in the development of media leading to the fully defined formulations that are now available for the cultivation of many of these organisms.

Cultivation of Clinically Significant Hemoflagellates

The cycle of Trypanosoma cruzi in tissue culture of embryonic heart muscle

On the relationship of infection by hookworm to the incidence of morbidity and mortality in 22,842 men of the united states army at camp bowie, texas, from october 1917, to april 1918.

Electrometric pH determinations of the walls and contents of the gastro-intestinal tracts of normal albino rats

Correlation of the Distribution of the Protozoa in the Intestine of Rattus norvegicus with the Hydrogen Ion Concentration of the Intestinal Contents and Wall.

Charles A. Kofoid

Papers

The cycle of Trypanosoma cruzi in tissue culture of embryonic heart muscle

On the relationship of infection by hookworm to the incidence of morbidity and mortality in 22,842 men of the united states army at camp bowie, texas, from october 1917, to april 1918.

Electrometric pH determinations of the walls and contents of the gastro-intestinal tracts of normal albino rats

Correlation of the Distribution of the Protozoa in the Intestine of Rattus norvegicus with the Hydrogen Ion Concentration of the Intestinal Contents and Wall.

Effects of arsenicals on trypanosoma cruzi in tissue culture