FAMILY BARTOXELLACEAE 



1105 



cit., 290.) From the genus of voles, 

 Microtus . 



In infected animal, morphology re- 

 sembles that of Haemobartonella canis, 

 the organisms occurring as rods, coccoids, 

 filaments, club forms, ring forms and 

 granular niasses. In addition to these 

 forms there occur in Giemsa-stained 

 blood films ovoids, diamond- or flame- 

 shaped small forms as well as coarse seg- 

 mented or unsegmented filaments up to 

 5 microns in length. Filaments may con- 

 tain one or more rings, or may be com- 

 posed in part or entirely of diamond- 

 shaped, coccoid or ovoid elements, some- 

 times in parallel rows. Rods often show 

 intense bipolar staining. Coccoid forms, 

 usually scattered, may occur as aggre- 

 gates or clumps on the red cell, appar- 

 ently embedded in a faint blue matrix. 



A pale blue veil-like substance may 

 cover nearly half of one surface of the 

 red cells and show at its border typical 

 red-violet stained rods or filaments in 

 the Giemsa-stained specimens. A bow- 

 shaped arrangement of elements is char- 

 acteristic. Organisms lie on the surface 

 of the red cells. In cultures organisms 

 are more uniform in morphology resembl- 

 ing Bartonella bacilliformis. Individual 

 organisms are fine rods, 0.3 by 1.0 to 2 

 microns, sometimes occurring in chains 

 and often in clumps. Small round forms 

 occur, measuring 0.5 micron in diameter, 

 and occasionallj' round disk-like struc- 

 tures. 



Cultivation: Growth in Noguchi's 

 semi-solid serum agar 2 weeks after in- 

 oculation with citrated or heparinized 

 blood and incubated at 23°C shows as 

 white rounded masses, measuring up to 

 about 1 mm in the upper 15 mm of the 

 tube. In tissue culture the organism 

 grows in snaall, rounded compact masses 

 within the cytoplasm of infected cells. 

 Indefinite maintenance of the strains 

 isolated on artificial media has not been 

 possible. 



Pathogenicity : Splenectomized white 

 mice and splenectomized laboratory 



reared voles are readily susceptible to 

 infection. Xo marked anemia or any 

 mortality in heavily infected animals. 

 Splenectomized dogs, white rats and deer 

 mice are not susceptible. 



Source and habitat : Erythrocytes of 

 the vole {Microlus pennsijlvanicus pemi- 

 sylvanicus) following splenectomy. 

 The natural mode of transmission has not 

 been determined though ticks or mites 

 are suspected. 



4. Haemobartonella tyzzeri (Wein- 

 man and Pinkerton) Weinman: (Bar- 

 tonella tyzzeri Weinman and Pinkerton, 

 Ann. Trop. Med., 33, 1938, 217; Wein- 

 man, Trans. Amer. Philosoph. Soc, 33, 

 1944, 314.) Named for Prof. Tyzzer 

 who studied haemobartonellae. 



Single or composite rods from about 

 0.25 micron by 1.4 to 4.0 microns. Occa- 

 sional granular swellings and enlarged 

 poles. Short rods also occur averaging 

 0.2 to 0.3 by 0.8 micron and also round 

 forms with diameters of 0.2 to 0.3 micron. 

 Distributed irregularly in the red cells. 



Stain intensely red-violet with 

 Giemsa's or May-Griinwald-Giemsa's so- 

 lutions. Gram-negative. 



Cultivation : Initial cultures on Nogu- 

 chi's semi-solid serum agar obtained ir- 

 regularly. When incubated at 28°C, 

 colonies appear as isolated white spheres 

 about 1 mm in diameter in the upper 8 

 mm border of the medium. The clumps 

 are composed of rods and granules, with 

 larger round structures or disks occurring 

 occasionally. Also cultivated on the 

 Zinsser, Wei and Fitzpatrick modifica- 

 tion of the ;Maitland medium. Pro- 

 longed maintenance on semi-solid media 

 has not been obtained. 



Pathogenicity: Splenectomized haemo- 

 bartonella-free guinea pigs may be 

 infected by blood or cultures injected 

 subcutaneously or intraperitoneally. 

 Splenectomized Haemobartonella muris- 

 free rats are insusceptible when inocu- 

 lated with infected guinea-pig blood. 

 Macacus rhesus monkeys are also in- 



