974 



ORDER I. RICKETTSIALES 



Proteus 0Xi9 , OXK and sera from rats re- 

 covered from haemobartonellosis. 



Pathogenicity: Infected blood, liver sus- 

 pension, defibrinated laked blood, washed 

 red blood cells, plasma and hemoglobinuric 

 urine may produce infection by the subcu- 

 taneous, intravenous, intraperitoneal or 

 intracardiac routes. Slight, transient or no 

 haemobartonellosis then occurs in adult, 

 non-splenectomized, haemobartonella-free, 

 albino rats; in adult, non-splenectomized, 

 albino rats of carrier stock; or finally in 

 adult, splenectomized rats previously in- 

 fected, during a period lasting 15 weeks to 

 8 months after infection. Typical haemobar- 

 tonellosis occurs in adult, splenectomized, 

 haemobartonella-free, albino rats and in 

 young, non-splenectomized, haemobarto- 

 nella-free, albino rats weighing 20 to 30 

 grams at 3 weeks. Latent infections regu- 

 larly become patent following splenectomy 

 and may follow coincident infections with 

 other microorganisms, chemotherapy, in- 

 jections of polonium nitrate or of "anti-rat- 

 spleen" serum. Variable results have been 

 obtained by different investigators with 

 wild mice, guinea pigs, rabbits, hamsters, 

 pigeons and monkeys {"Macacus rhesus" 

 and Macacus sp.). Known to be infectious 

 for wild rats, albino mice, rabbits and for 

 two Palestinian rodents (Spalax typhlops 

 and Meriones tristrami). Negative results 

 have been reported in dogs, kittens, cats, 

 sheep and various birds. Causes a definite 

 and characteristic anemia without cutane- 

 ous eruption. 



Antibiotic- and chemo-therapy: Penicillin 

 is ineffective; there is true sterilization of 

 latent or recognized infection with organic 

 arsenical compounds; chlortetracycline (au- 

 reomycin) and oxytetracycline (terramycin) 

 are active. 



Source: Found in the blood of infected 

 albino rats. 



Habitat: Found in ectoparasites such as 

 the rat louse (Polyplax spinulosus) , the flea 

 {Xenopsylla cheopis) and possibly the bed- 

 bug (Cimex lectularius) . Also found para- 

 sitizing the erythrocytes of susceptible 

 animals. World wide distribution. 



2. Haemobartonella microti Tyzzer 

 and Weinman, 1939. (Tyzzer and Weinman, 



Amer. Jour. Hyg., 30 (B), 1939, 143; also see 

 Weinman, Trans. Amer. Philosoph. Soc, 

 33 (N.S.), 1944,312.) 



mi.cro' ti. M.L. mas.n. Microtus a genus 

 of voles; M.L. gen. noun microti of Microtus. 



In infected animals the morphology re- 

 sembles that of Haemohartonella canis, the 

 organisms occurring as rods, coccoids, 

 filaments, club forms, ring forms and granu- 

 lar masses. In addition to these forms there 

 occur in Giemsa-stained blood films ellips- 

 oids and diamond- or flame-shaped small 

 forms as well as coarse, segmented or un- 

 segmented filaments up to 5 microns in 

 length. The filaments may contain one or 

 more rings or may be composed in part or 

 entirely of diamond-shaped, coccoid or 

 ovoid elements, sometimes arranged in 

 parallel rows. Rods often show intense 

 bipolar staining. Coccoid forms, usually 

 scattered, may occur as aggregates or 

 clumps on the red blood cell, apparently 

 embedded in a faint blue matrix. A pale 

 blue, veil-like substance may cover nearly 

 half of one surface of the red blood cell 

 and show, at its border, typical red- 

 violet -stained rods or filaments in the 

 Giemsa-stained specimens. A bow -shaped 

 arrangement of elements is characteristic. 

 Morphology varies markedly with the kind 

 of host employed. Organisms lie on the sur- 

 faces of the red blood cells. In cultures, 

 organisms are more uniform in morphology. 

 Individual organisms are fine rods, 0.3 by 

 1.0 to 2.0 microns, sometimes occurring in 

 chains and often in clumps. Small, round 

 forms measuring 0.5 micron in diameter 

 and occasionally round, disc-like structures 

 occur. 



Cultivation: Growth in Noguchi's semi- 

 solid serum agar two weeks after inoculation 

 with citrated or heparinized blood and in- 

 cubated at 23° C. appears 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 small, rounded, com- 

 pact masses within the cytoplasm of in- 

 fected 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. 



