rickettsial (rickettsia) infection limited to South America, caused by the bacterium Bartonella bacilliformis of the order Rickettsiales. Bartonellosis is characterized by two distinctive clinical stages: Oroya fever, an acute febrile anemia of rapid onset, bone and joint pains, and a high mortality if untreated, and verruga peruana, a more benign skin eruption characterized by reddish papules and nodules, which usually follows the Oroya fever but may also occur in individuals who have not exhibited previous symptoms. The skin lesions are thought to be an expression of developing immunity in the affected persons; reinfection is extremely rare.