Bartonella is a group of bacteria that causes infectious diseases and are mainly transmitted by carriers such as fleas, lice, or sandflies. Theses carriers are also called vectors. One species of the Bartonella bacteria is the Bartonella bacilliformis which causes a vector-borne illness called Carrion disease. This bacterium is primarily carried and transmitted to humans often via the bite of a sandfly, particularly two vector species which are Phlebotomus verrucarum and Lutzomyia verrucarum. When the Bartonella bacilliformis bacterium enters the bloodstream, it attaches itself to the surface of the red blood cells and the interior surface of blood vessels called the endothelial cells. During the invasion of the bloodstream, this bacterium then reproduces itself, causing abnormal fragility and premature destruction of the red blood cells, a process called hemolysis. Further damage causes decreasing levels of red blood cells and reduction of hemoglobin concentrations, which results in anemia. This bacterium may also affect the capillary endothelial cells by invading the cell lining of small blood vessels which may cause potential blockage of normal blood flow. When the hemolytic anemia becomes severe and abnormal blood clots are formed in the small blood vessels, this infection may turn in to a life-threatening condition.
Due to the presence of sandflies carrying this bacterium, most of the cases of Bartonella bacilliformis infections occur endemically in the South American Andes including Colombia, Peru, and Ecuador.
