FAMILY I. RICKETTSIACEAE 949 



Key to the genera of tribe Ehrlichieae. 



I. Transmitted by ticks. 



A. Transmitted transovarially; parasites of circulating monocytes of vertebrate hosts. 



Genus III. Ehrlichia, p. 949. 



B. Not transmitted transovarially; parasites of endothelial cells of vertebrate hosts. 



Genus IV. Cowdria, p. 950. 

 II. Transmitted by parasitic trematodes; pathogenic principally for canines. 



Genus V. Neorickettsia, p. 951. 



Genus III. Ehrlichia Moshkovskiy, {1937) 1945. 



(Subgenus Ehrlichia Moshkovskiy , Compt. rend. Soc. Biol., Paris, 126, 1937, 382; Ehrlichia 

 Moshkovskiy, Uspekhi Souremennoi Biol. (U.S.S.R.), 19, 1945, 10; Nicollea (in part) Mac- 

 chiavello, Prim. Reunion Interamer. del Tifo, Mexico, 1947, 416; possibly Donatienella 

 Rousselot, Bull. Soc. path, exot., 41, 1948, 110.) 



Ehr.li'chi.a. M.L. noun Ehrlichia named for Paul Ehrlich, a German bacteriologist. 



Small, often pleomorphic, usually coccoid organisms occurring intracytoplasmically in 

 the circulating monocytes of suitable mammalian hosts. Parasitic. The etiological agents 

 of tick-borne diseases of dogs, cattle and sheep. 



The type species is Ehrlichia canis (Donatien and Lestoquard) Moshkovskiy. 



Key to the species of genus Ehrlichia. 



I. Causes a serious and often fatal disease of dogs. 



1. Ehrlichia canis. 

 II. Cause diseases of ruminants. 



A. Causes a non-fatal disease of cattle. 



2. Ehrlichia bovis. 



B. Causes a rickettsia-like disease of sheep. 



3. Ehrlichia ovina. 



1. Ehrlichia canis (Donatien and Lesto- Immunology: Not reported, 



quard, 1935) Moshkovskiy, (1937) 1945. Pathogenicity: Reported as causing a 



{Rickettsia canis Donatien and Lestoquard, serious and often fatal disease in dogs in 



Bull. Soc. path, exot., 28, 1935, 418; Ehrlichia North and East Africa. Injection of a mon- 



{Rickettsia) canis Moshkovskiy, Compt. key, Maccacus innuus, caused a febrile 



rend. Soc. Biol., Paris, 126, 1937, 382; response with attendant rickettsiemia. The 



Ehrlichia canis Moshkovskiy, Uspekhi ordinary laboratory animals are not sus- 



Souremennoi Biol. (U.S.S.R.), 19, 1945, 18; ceptible. 



Nicollea canis MucchiSiYQWo, Prim. Reunion Comment: Regarded as the type species 



Interamer. del Tifo, Mexico, 1947, 416; of the genus Ehrlichia by Moshkovskiy (op. 



Kurlovia {Ehrlichia) canis Zhdanov, Oprede- cit., 1945). 



litel Virusov Celovska i Zivotmych, Izd. Source: Observed by Donatien and Lesto- 



Akad. Med. Nauk, U.S.S.R., Moskau, 1953, quard (op. cit., 1935) in the cytoplasm of 



57 and 168.) monocytes of dogs infected by tick bite in 



ca'nis. M.L. noun canis the dog. Algeria. 



Minute, coccoid, ellipsoidal or boat- Habitat: Found in the common dog tick, 



shaped organisms, 0.2 to 0.3 micron in di- Rhipicephalu s sanguineus, aW singes oi\vh.ich. 



ameter, occurring intracytoplasmically in are reported to transmit the infection and in 



plaques or colonies in the circulating mono- which transovarial passage has been ob- 



cytes of infected dogs. Stain blue with served. 

 Giemsa's stain. 



Cultivation: Not reported. 2. Ehrlichia bovis (Donatien and Lesto- 



Serology: Not reported. quard, 1936) Moshkovskiy, 1945. {Rickettsia 



