972 ORDER I. RICKETTSIALES 



normal host, the deer mouse (Peromyscus Grahamella peromysci has been described 



leucopus novaboracensis), but not the white here only in order to include information on 



Swiss mouse. Monkeys {Macaca vmlatta) are the cultural characteristics of the genus 



not infected by cultures. Grahamella, and no opinion as to the validity 



Comment: Numerous species of Gra- of this species is expressed thereby. 



hamella have been named according to their Source and habitat: Occurs naturally in 



hosts, and there is no satisfactory evidence the deer mouse {Peromyscus leucopus nova- 



that they are different microorganisms. boracensis). 



Genus III. Haemobartonella Tyzzer and Weinman, 1939.* 

 (Amer. Jour. Hyg., 30 (B), 1939, 141.) 



Hae.mo.bar.to.nel'la. Gr. noun haema blood; M.L. fem.dim.n. Bartonella tj^pe genus of 

 the family Bartonellaceae; M.L. fem.dim.n. Haemobartonella the blood(-inhabiting) Bar- 

 tonella. 



Parasites of the red blood cells. There is no demonstrable multiplication in tissues, and 

 cutaneous eruptions are not produced. Typically rod-shaped or coccoid organisms which 

 show no differentiation into nucleus and cytoplasm. The morphological range may vary with 

 the type of host employed. Stain well with Romano wsky-type stains and poorly with many 

 other aniline dyes. Not acid-alcohol-fast. Gram-negative. Not cultivated indefinitely in 

 cell-free media. Distributed over the surface of the erythrocytes and possibly sometimes 

 within them. Rarely produce disease in animals without splenectomy. The experimental 

 host range is restricted: an organism infective for one species of rodent may commonly in- 

 fect other rodents but not primates. Markedly influenced by arsenotherapy but, so far as 

 is known, do not respond to penicillin. Occur naturally as parasites of vertebrates. Trans- 

 mitted by arthropods. Geographical distribution of the best-studied species is similar to 

 that of the vertebrate host and may be world wide. 



The type species is Haemobartonella maris (Mayer) Tyzzer and Weinman. 



Key to the species of genus Haemobartonella. f 



I. Found in rodents. 



A. Found in the albino rat. 



B. Found in the vole. 



C. Found in the guinea pig. 



D. Found in the deer mouse. 



E. Found in squirrels. 



II. Not found in rodents. 



A. Found in herbivorous animals. 

 1. Found in the cow. 



1. Haemobartonella muris. 



2. Haemobartonella microti. 



3. Haemobartonella tyzzeri. 



4. Haemobartonella peromysci. 



5. Haemobartonella sciuri. 



6. Haemobartonella bovis. 



* Revised by Dr. David Weinman, Department of Microbiology, Yale University, New 

 Haven, Connecticut, September, 1955. 



t The species in this genus are not j^et well defined. For convenience they have been ar- 

 ranged here according to their usual hosts even though it may be evident from their de- 

 scriptions that other criteria are used and are sometimes essential for establishing their 

 individuality. In all probability the organisms listed here are distinct species, although it 

 may eventually be shown that this arrangement does not represent their true relationships. 



