or a cutaneous eruption, usuallj' both in succession, not both coincidentally. Found in man and Phlebotomus spp. Genus I. Bartonella, p. 969. II. Not known to multiply in fixed-tissue cells; parasitize erythrocytes and may multiply there. Flagella not demonstrated. Occur in mammals and possibly in other vertebrates, but not known from man. A. Usually parasitize less than 5 per cent of the total erythrocytes, rarely more. Rela- tively monomorphic in erythrocytes. Non-pathogenic or only slightly so. Affected little, if at all, by splenectomy. Cultivable on non-living media. Occur within the red blood cells; epi-erythrocytic forms are problematical. Genus II. Grahamella, p. 971. B. Parasitized cells may constitute more than 90 per cent of the total erythrocytes at the peak of infection. Polymorphism is marked when in or on red blood cells. May or may not be pathogenic. Marked increase in numbers following splenectomy. Culti- vation on non-living media not confirmed. Occur on the red blood cells; situation within red cells possible but not proved. 1. Extremely polymorphic; however, rods of varying sizes almost invariably occur, often in chains. Habitat predominantly epi-erythrocytic. Usually pathogenic, provoking a progressive, sometimes fatal, anemia. Genus III. Haemobartonella, p. 972. 2. Fundamental morphological type is ring- or disc-shaped. Rods are one disc- or ring-diameter in length; composite rods are made of these units. Occur in great numbers in the blood plasma as well as on the erythrocytes. Usually non -patho- genic. Genus IV. Eperythrozoon, p. 977. Genus I. Bartonella Strong, Tyzzer and Sellards, 1915. {Bartonia Strong, Tyzzer, Brues, Sellards and Gastiaburu, Jour. Amer. Med. Assoc, 61, 1913, 1715; not Bartonia Miihlenberg, in Willdenow, Neue Schrift Ges. Nat. Fr., Berlin, 3, 1801, 444; not Bartonia Sims, Bot. Mag., 1804; not Bartonia Grossman, Essais de Paleoconchologie Comparee, 4« Livr., Paris, 1901; Strong, Tyzzer and Sellards, Jour. Amer. Med. Assoc, 64, 1915, 808; also see Tyzzer and Weinman, Amer. Jour. Hyg., 30 (B), 1939, 143; and Weinman, Trans. Amer. Philosoph. Soc, S3, (N.S.), 1944, 246.) Bar.to.nel'la. M.L. dim. ending -ella; M.L. fem.dim.n. Bartonella named for Dr. A. L. Barton, who described these organisms in 1909. Microorganisms which multiply in fixed-tissue cells and on erythrocytes. On the red blood cells in stained films, the organisms appear as rounded or ellipsoidal forms or as slender, straight, curved or bent rods occurring either singly or in groups. Characteristically occur in chains of several segmenting organisms, sometimes swollen at one or both ends and fre- quently beaded (Strong et al., op. cit., 1913, 1715), without a distinct differentiation of nu- cleus and cytoplasm. In the tissues they are situated within the cytoplasm of endothelial cells as isolated elements and are grouped in rounded masses. Possess independent motility. Reproduce by binary fission. May be cultivated by unlimited serial transfers on cell-free media. Occur spontaneously in man and in arthropod vectors. One species has been recog- nized, and it is known to be established only on the South American continent and perhaps in Central America. Human bartonellosis may be manifested clinically by one of the two syndromes constituting Carrion's disease (Oroya fever or Verruga Peruana) or by an asymp- tomatic infection. The type species is Bartonella bacilliformis (Strong et al.) Strong et al.
