bartonella bartonella bartonella is a genus of gram-negative bacteria. it is the only genus in the family bartonellaceae. facultative intracellular parasites, bartonella species can infect healthy people, but are considered especially important as opportunistic pathogens. bartonella species are transmitted by vectors such as ticks, fleas, sand flies, and mosquitoes. at least eight bartonella species or subspecies are known to infect humans. this article is about the bacteria. for the disease, see bartonellosis. bartonella scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: hyphomicrobiales family: bartonellaceaegieszczykiewicz 1939 (approved lists 1980) genus: bartonellastrong et al. 1915 (approved lists 1980) species b. acomydis b. alsatica b. ancashensis "candidatus b. antechini" b. apis b. australis b. bacilliformis "candidatus b. bandicootii" b. birtlesii b. bovis "candidatus b. breitschwerdtii" b. callosciuri b. capreoli b. chomelii b. clarridgeiae b. coopersplainsensis b. doshiae "candidatus b. durdenii" "candidatus b. eldjazairii" b. elizabethae b. florencae b. fuyuanensis b. gabonensis b. grahamii b. heixiaziensis b. henselae b. jaculi b. japonica b. koehlerae b. kosoyi b. krasnovii b. mastomydis "candidatus b. mayotimonensis" "candidatus b. melophagi" "candidatus b. merieuxii" "candidatus b. monaxi" b. naantaliensis "candidatus b. ovis" b. pachyuromydis b. peromysci b. phoceensis b. queenslandensis b. quintana b. rattaustraliani b. rattimassiliensis b. rochalimae "candidatus b. rudakovii" b. saheliensis b. schoenbuchensis b. senegalensis b. silvatica b. silvicola b. talpae b. tamiae b. taylorii "candidatus b. thailandensis" b. tribocorum b. vinsonii spp. arupensis spp. berkhoffii spp. vinsonii spp. yucatanensis "candidatus b. volans" b. washoensis "candidatus b. woyliei" synonyms bartonia strong et al. 1913 grahamella (ex brumpt 1911) ristic and kreier 1984 rochalimaea (macchiavello 1947) krieg 1961 bartonella henselae is the organism responsible for cat scratch disease. history bartonella species have been infecting humans for thousands of years, as demonstrated by bartonella quintana dna in a 4000-year-old tooth. the genus is named for alberto leonardo barton thompson (1871–october 26, 1950), a peruvian scientist. infection cycle the currently accepted model explaining the infection cycle holds that the transmitting vectors are blood-sucking arthropods and the reservoir hosts are mammals. immediately after infection, the bacteria colonize a primary niche, the endothelial cells. every five days, some of the bartonella bacteria in the endothelial cells are released into the blood stream, where they infect erythrocytes. the bacteria then invade a phagosomal membrane inside the erythrocytes, where they multiply until they reach a critical population density. at this point, they simply wait until they are taken up with the erythrocytes by a blood-sucking arthropod. though some studies have found "no definitive evidence of transmission by a tick to a vertebrate host," bartonella species are well-known to be transmissible to both animals and humans through various other vectors, such as fleas, lice, and sand flies. recent studies have shown a strong correlation between tick exposure and bartonellosis, including human bartonellosis. bartonella bacteria are associated with cat-scratch disease, but a study in 2010 concluded, "clinicians should be aware that . . . a history of an animal scratch or bite is not necessary for disease transmission." all current bartonella species identified in canines are human pathogens. pathophysiology bartonella infections are remarkable in the wide range of symptoms they can produce. the course of the diseases (acute or chronic) and the underlying pathologies are highly variable. bartonella pathophysiology in humans specieshuman reservoir orincidental host?animalreservoirpathophysiologydistribution b. bacilliformisreservoircauses carrion's disease (oroya fever, verruga peruana)peru, ecuador, and colombia b. quintanareservoirjapanese macaquecauses trench fever, bacillary angiomatosis, and endocarditisworldwide b. clarridgeiaeincidentaldomestic catcat scratch disease b. elizabethaeincidentalratendocarditis b. grahamiiincidentalmouseendocarditis and neuroretinitis b. henselaeincidentaldomestic catcat scratch disease, bacillary angiomatosis, peliosis hepatis, endocarditis, bacteremia with fever, neuroretinitis, meningitis, encephalitisworldwide b. koehleraeincidentaldomestic cat b. naantaliensis reservoir myotis daubentonii b. vinsoniiincidentalmouse, dog, domestic catendocarditis, bacteremia b. washoensisincidentalsquirrelmyocarditis b. rochalimaeincidentalunknowncarrion's disease-like symptoms