980 



ORDER I. RICKETTSIALES 



up to 2.5 microns also occur. This is per- 

 haps the largest species in the genus. 



Cultivation has not been successful. 



Immunologj^: Latent infection made man- 

 ifest by splenectomy; under field condi- 

 tions, animals with spleen sicken and pre- 

 sent massive infections. 



Pathogenicity: Implicated in "ictero- 

 anemia" of swine, heavy infection and dis- 

 ease being provoked without splenectomy. 

 Has not infected one or more of: lamb, calf 

 and the following splenectomized animals: 

 white mouse, deer mouse (Peromyscus man- 

 iculatus), rats, guinea pigs and rabbits. 



Chemotherapy: Neoarsphenamine, at 

 doses of 15 milligrams per kilogram of pig, 

 is effective in controlling the infection. 



Source: Occurs in the blood of swine in 

 the United States and perhaps in the Bel- 

 gian Congo. 



7. Eperythrozoon parvuni Splitter, 

 1950. (Science, 111, 1950, 513.) 

 par'vum. L. adj. parvus small. 



One of the smallest of the eperythrozoa. 

 Disc or coccus forms measuring less than 

 0.5 micron in diameter predominate and 

 are mixed with occasional ring forms 0.5 to 

 0.8 micron in diameter. Filterable through 

 Seitz EK and Berkefeld W filters and by 

 this means can be separated from E. suis, 

 which does not pass these filters. 



Differentiation from E. sids is based on 

 size, on morphological differences and on 

 the failure of either species to cross-immu- 

 nize against the other. Resembles E. dispar 

 in appearance, and the two have not been 

 proved to be distinct. 



Rarely pathogenic. Has not infected one 

 or more of: calf, lamb, splenectomized white 

 mouse and splenectomized Peromyscus ma- 

 niculatus. 



Chemotherapy: Relatively resistant to 

 neoarsphenamine in vivo, frequently resist- 

 ing doses of 45 milligrams per kilogram of 

 hog. 



Source: Found in the blood of swine in 

 the United States. 



FAMILY IV. ANAPLASMATACEAE PHILIP, Fam. Nov.* 



{Anaplasmidae Lestoquard, Les piroplasmoses du mouton et de la chevre. Inst. 



Past. d'Algerie, 1926; also see Yakimov, Handbook of Protozoology, Moscow, 



1931; and Neitz, Alexander and du Toit, Onderstepoort Jour. Vet. Sci. 



and Anim. Ind., 3, 1934, 263.) 



A.na.plas.ma.ta'ce.ae. Gr. neut.n. Anaplasma type genus of the family; -aceae ending 

 to denote a family; M.L. fem.pl.n. Anaplasmataceae the Anaplasma family. 



Organisms which parasitize red blood cells. There is no demonstrable multiplication in 

 other tissues. In blood smears fixed with May-Griinwald and stained with Giemsa's stain, 

 these organisms appear in the erythrocytes as spherical chromatic granules which stain a 

 deep reddish violet color. Show no differentiation into nucleus and cytoplasm. Occur natu- 

 rally as parasites of ruminants. Transmitted by arthropods. Situated at or near the margin 

 and/or at or near the center of the red blood cells. The position within the erythrocyte 

 and/or host differences serve as bases for differentiating species. Attempts at cultivation 

 in a variety of media have failed. Produce disease in non-splenectomized and in splenec- 

 tomized ruminants. The natural and experimental host range is fairly wide, these organ- 

 isms occurring in members of the families Bovidae and Camelidae. Influenced by aureomycin 

 and terramycin. Widely distributed throughout the world. 



There is a single genus. 



* Arranged by Dr. Cornelius B. Philip, Rocky Mountain Laboratory, Hamilton, Mon- 

 tana, March, 1956; see Canad. Jour. Microbiol, 2, 1956, 269. 



