General Information: Bartonella grahamii (strain as4aup) is Gram-negative bacterium isolated from a wood mouse (Apodemus sylvaticus) in central Sweden. Bartonella are human and animal pathogens which infect erythrocytes and can cause angiogenic lesions. These organisms cause diseases in humans such as Oroya fever, Trench fever, endocarditis, and Cat Scratch disease. Transmission of this organism is via the bite of a blood-sucking arthropod. Bartonella grahamii can be isolated from the blood of rodents and is found world wide. Fleas may be the transmission vector for Bartonella grahamii to other rodents. Human disease appears to be rare and associated with an immunocompromised state.