ABSTRACT
For several decades, the genus Bartonella consisted of a single species, Bartonella bacilli/armis, which is the agent of Carrion's disease, a unique biphasic infection that is endemic to the valleys of the South American Andes in Peru, Columbia, and Ecuador. In endemic regions, members of indigenous populations usually show symptoms of verruga peruana, the secondary eruptive phase of Carrion's disease, whereas visitors to these regions develop a primary febrile hemolytic illness termed aroya fever. Probably the most dramatic outbreak of aroya fever occurred during the construction of the railroad from Lima to La Oroya between 1869 and 1873. La aroya is a rich mining center 5000 metres above sea level. At the time, more than 10,000 labourers were hired mainly from Chile and the coastal cities of Peru which were areas where B. bacilli/armis infections were not endemic. It was estimated that at least 8,000 workers contracted an illness that was characterized by fever and anemia and that most of them died. The "Puente de Verrugas", a viaduct of the trans-Andean railroad in this area, bears witness to this epidemic. The biphasic nature of the disease confused many investigators. Even railroad company physicians and Peruvians believed that the two stages were caused by two different etiological agents (1,2). A 26-year-old Peruvian medical student, Daniel Alcides Carrion, set out to demonstrate that both phases were caused by the same pathogen. In August 1885, he heroically inoculated himself with secretions from a skin lesion of a patient with verruga peruana. Three weeks after inoculation, he developed fevt;:r and anemia; his red blood cell count decreased precipitously. Daniel Carrion died a few weeks later, and the illness now bears his name (2,3).
