Oroya fever is a disease caused by the bacterium Bartonella bacilliformis, which is transmitted through the bite of infected sandflies. It primarily occurs in the Andean regions of Peru, Ecuador, and Colombia. The disease is characterized by two phases: an acute phase with high fever, chills, and anemia, followed by a chronic phase known as verruga peruana, which involves skin lesions. Diagnosis of Oroya fever is typically made through blood tests that detect the bacteria. Treatment usually involves antibiotics, such as doxycycline or chloramphenicol. If left untreated, Oroya fever can lead to severe complications, including death. Early detection and treatment are crucial for recovery.