Bartonella are pathogens that causes Bartonellosis. They are mainly transmitted by carriers (vectors), including fleas, lice, or sandflies, and can be transmitted from animals to people. Human diseases that have been identified to be caused by one of the Bartonella spp bacteria include cat scratch disease (Bartonella henselae), Carrion’s disease (Bartonella bacilliformis), and trench fever (Bartonella quintana).