Carrin's disease is a biphasic disease caused by B. bacilliformis, which is transmitted by a sandfly vector found in the Andes valleys of Peru, Ecuador, and Colombia.

• Oroya fever is the initial, bacteremic, systemic form, and verruga peruana is its late-onset, eruptive manifestation.
• Oroya fever may present as a nonspecific bacteremic febrile illness without anemia or as acute, severe hemolytic anemia with hepatomegaly and jaundice of rapid onset.
  • - In verruga peruana, red, hemangioma-like, cutaneous vascular lesions of various sizes appear either weeks to months after systemic illness or with no previous suggestive history. The lesions persist for months up to 1 year.
• In systemic illness, Giemsa-stained blood films show typical intraerythrocytic bacilli, and blood and bone marrow cultures are positive. Serologic assays may be helpful. Biopsy may be required to confirm the diagnosis of verruga peruana.