General Information: Cauative agent of Carrion's disease. Like other members of this genus, Bartonella bacilliformis is an obligate intracellular parasite, which infects red blood cells. Bartonella bacilliformis is the causative agent of Carrion's disease, also called Oroya fever. This disease is found in the western Andes of South America, and is transmitted through an insect vector. Carrion's disease is characterized by an acute, febrile, anemia with a mortality of 40 to 90%. The anemic phase may be followed by a milder secondary episode, characterized by wart-like skin lesions.