FAMILY III. BARTONELLACEAE 



975 



Neither marked anemia nor anj^ mortality 

 occurs in heavil}' infected animals. Splenec- 

 tomized dogs, white rats and deer mice are 

 not susceptible. 



Source and habitat: Occurs in the blood 

 of the vole (Microtus pennsylvanicus penn- 

 sylvanicus). The natural mode of transmis- 

 sion has not been determined, though ticks 

 and mites are suspected. 



3. Ilaemobartonella lyzzeri (Weinman 

 and Pinkerton, 1938) Weinman, 1944. 

 (Bartonella iyzzeri Weinman and Pinkerton, 

 Ann. Trop. Med., 32, 1938, 217; Weinman, 

 Trans. Amer. Philosoph. Soc, 33 (N.S.), 

 1944, 314.) 



tyz'ze.ri. M.L. gen. noun iyzzeri of Tyzzer; 

 named for Dr. E. E. Tyzzer, protistologist 

 and investigator of this group of microor- 

 ganisms. 



Single or composite rods measuring about 

 0.25 by 1.4 to 4.0 microns. Short rods averag- 

 ing 0.2 to 0.3 by 0.8 micron as well as round 

 forms with diameters of 0.2 to 0.3 micron 

 also occur. Occasional granular swellings 

 and enlarged poles occur. Stain intensely 

 red-violet with Giemsa's or with May- 

 Griinwald-Giemsa's solutions. Gram-nega- 

 tive. 



Cultivation: Initial cultures on Noguchi's 

 semi-solid serum agar are obtained irregu- 

 larlj\ 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 discs occurring occasionally. 

 Also cultivated on the Zinsser, Wei and 

 Fitzpatrick modification of the Maitland 

 medium. Prolonged maintenance on semi- 

 solid media has not been obtained. 



Pathogenicity: Splenectomized, haemo- 

 bartonella-free guinea pigs may be infected 

 by blood or by cultures injected subcutane- 

 ously or intraperitoneally. Splenectomized, 

 Haemobartonella muris-free rats are not sus- 

 ceptible when inoculated with infected 

 guinea-pig blood. Monkeys (Macacus rhesus) 

 are also not susceptible to inoculations of 

 infected blood, tissue and cultures. Infec- 

 tion of the guinea pig is subclinical in its 

 manifestations. 



No definite anemia accompanies infection. 



Comment: Since 1944, at which time this 

 species was classified as belonging to the 

 genus Haemobartonella, knowledge has 

 accrued which suggests a restudy to deter- 

 mine whether this species might more 

 properly be placed in the genus Grahamella. 



Source and habitat: Found in the blood 

 of the Peruvian guinea pig (Cavia porcellvs) ; 

 also encountered in the blood of native 

 guinea pigs in Colombia. Observed in la- 

 tently infected animals only after splenec- 

 tomy. The natural mode of transmission is 

 unknown, although the flea may be a possi- 

 ble vector. 



4. Haemobartonella peronij sci Tyzzer, 

 1942. (Proc. Amer. Philosoph. Soc, 85, 1942, 



377.) 



pe.ro. mys'ci. M.L. mas.n. Peromyscus a 

 genus of mice; M. L. gen. noun peromysci of 

 Peromyscus. 



Occurs as delicate, filamentous forms 

 (which may be branched) on red blood cells. 

 These filaments may become beaded and 

 may give rise to a number of coccoids and 

 rods from which ring forms may develop. 

 Stains by Giemsa's method, but the staining 

 process must be intense in order to demon- 

 strate the organism. 



Pathogenicity: Infection transmissible to 

 splenectomized white rats (irregularly), 

 white mice (frequently) and voles, produc- 

 ing a more or less severe illness with anemia. 



Habitat: Found in the blood of deer mice 

 (Peromyscus leucopus novaboracensis) . 



5. Haemobartonella sciiiri Tyzzer, 

 1942. (Proc. Amer. Philosoph. Soc, 85, 1942, 

 385.) 



sci.u'ri. M.L. mas.n. Sciurus a genus of 

 squirrels; M.L. gen. noun sciuri of Sciurus. 



Very polymorphic Occurs as minute rods 

 and filaments which are either continuous 

 or segmented. The rods and filaments vary 

 in thickness, some being very uneven and 

 some very coarse. Beaded chains may de- 

 velop from the thickened forms. The bead- 

 like elements stain a dull reddish at the 

 periphery with Giemsa's stain, while the 

 remainder is very faintly stained in con- 

 trast to the intensely staining basophilic 

 rods and filaments. Some of the rounded 

 forms have the appearance of large, thick 



