Disease eradication has often been likened to a siren song; the task has an immediate allure and a deceptive ease, yet many efforts to master eradication have floundered. The International Health Commission first encountered bilharzia (schistosomiasis) while conducting some of the first hookworm campaigns outside of the American South. While surveying the burden of hookworm in Egypt, staff stumbled across the true scale of schistosome fluke infection across the country. The Rockefeller Foundation's International Health Division returned to Egypt in 1929 and commenced an eleven-year eradication campaign overseen by parasitologists Claude Barlow and J. Allen Scott. What began as a seemingly simple mission to evaluate the success of sanitation interventions in rural villages soon became a complex and fraught program pitting both men against each other, local opinion, and the orthodoxies of international public health experts. In this research report, reflecting on one part of my wider research on the history of eradication thinking in public health, I focus on the important work of Barlow and overview significant aspects of his collected written communication held in the Rockefeller Archive Center. Beginning as an optimistic advocate of eradication, Barlow's experiences in Egypt transformed his views on the likelihood of elimination and – in important ways – foreshadows the ethical, socio-political, and technical limits currently emerging around contemporary philanthropic drives to eradicate infectious diseases.