This article examines a debate that emerged in El Paso, Texas at the turn of the twentieth century surrounding the transmission of pulmonary tuberculosis from predominantly Anglo American migrants to the city's ethnic Mexican population. Reports of Anglo-to-Mexican infections came from cities and towns throughout the U.S. Southwest, but by 1915 El Paso had emerged as the epicenter of the debate. Using popular and professional sources, the article tracks a shift in dominant perceptions of tubercular contagion from an association with white bodies to Mexican ones. An early narrative casts the Mexican female domestic servant as a victim of the infectious indigent white consumptive male health seeker. In 1915, as the Mexican Revolution raged and tensions between whites and ethnic Mexicans in the city sharpened, federal public health authorities published a report dismissing health seekers as a source of contagion to ethnic Mexicans. This article highlights the power of notions of race, gender, and class in shaping perceptions of and responses to epidemics, often with tragic results.