SARCOCYSTIS, TOXOPLASMA AND RELATED PROTOZOA 



341 



inoculation of peritoneal fluid from acutely 

 ill animals or by trophozoites from cysts 

 of chronically affected animals to white 

 mice, rats, hamsters, voles (Microtiis), 

 ground squirrels (Citellus) and chicken 

 embryos, but not to guinea pigs, rabbits, 

 the ox, rhesus monkey, baby chick, ca- 

 nary or pigeon (Frenkel, 1956a). Jellison, 

 Fullerton and Parker (1956) transmitted it 

 to mice by feeding trophozoites from cysts 

 or peritoneal fluid of affected animals. 



The cysts occur in the connective 

 tissue and on the serosae of many of the 

 viscera organs, including the intestine, 

 liver, spleen, heart, testes, etc. They 

 are spherical, up to 1 mm in diameter, 

 with thick walls containing giant nuclei. 

 The wall is positive to the periodic acid- 

 Schiff reaction and is unaffected by salivary 

 digestion. 



The trophozoites are crescent-shaped, 

 with a central nucleus. According to 

 Goldman, Carver and Sulzer (1957, 1958), 

 who studied them after staining with Bodian 

 silver stain, they have a truncated, cap- 

 like cone at the anterior end with 1 or 

 more rod- or fibril-like structures ex- 

 tending posteriorly from it, a dark-stain- 

 ing posterior granule and a nucleus con- 

 sisting of a larger, less dense portion and 

 a smaller, more compact structure. They 

 reproduce by endodyogeny. 



B. jellisoni may cause an acute, fatal 

 disease or a chronic one. 



for a final decision to be made. It differs 

 from Toxoplasma in that its trophozoites 

 are smaller and rod-shaped; the clusters 

 of trophozoites in the brain are not sur- 

 rounded by an argyrophilic cyst wall, altho 

 they are said to form a pseudocyst; En- 

 cephalitozooji stains very poorly with 

 hematoxylin and eosin but stains dark red 

 with Wright and Craighead's carbol fuchsin- 

 methylene blue stain (decolorized with 37% 

 formaldehyde solution), whereas Toxo- 

 plasma stains well with hematoxylin and 

 eosin and stains blue with carbol fuchsin- 

 methylene blue; Eiiceplialitozoon stains 

 black with Weigert's iron hematoxylin, 

 whereas Toxoplasma does not; and Enceph- 

 alitozooii survives rapid freezing and stor- 

 age at -70° C or storage in 50% buffered 

 glycerol at 4° C, while Toxoplasma does 

 not (Perrin, 1943a; Frenkel, 1956). 



Several species of Eiiceplialitozoon 

 have been named, and the name has also 

 been mistakenly given to the Negri bodies 

 of rabies. However, in view of the trans- 

 missibility of the organism from one host 

 to another, only a single species deserves 

 recognition. Even this has been ques- 

 tioned. Robinson (1954) claimed that the 

 structures described under this name are 

 actually ceroid pigment or hemofuscin. 

 Unfortunately, none of the 11 photomicro- 

 graphs of tissue sections in his paper 

 shows these structures, so that there is 

 no clear evidence of what he was actually 

 dealing with. 



B. jellisoni is serologically and im- 

 munologically distinct from Toxoplasma 

 and also from B. besnoiti. Goldman, 

 Carver and Sulzer (1957) found that fluor- 

 escein-labelled Toxoplasma antibody did 

 not stain 5. jellisoni, and Frenkel (1955) 

 found that sera from cows naturally in- 

 fected with B. besnoiti did not react with 

 B. jellisoni in the dye test. 



Genus ENCEPHAUTOZOON 

 Levaditi, Nicolau and Schoen, 1923 



This genus closely resembles Toxo- 

 plasma and may indeed eventually turn out 

 to be a synonym of it, as Biocca (1949) 

 believed. It is too poorly known, however, 



ENCEPHAUTOZOON C UNIC ULI 

 LEVADITI, NICOLAU AND 

 SCHOEN, 1923 



Synonyms : Encephalitozoon negrii. 



Disease : Encephalitozoonosis. 



Hosts : Domestic rabbit, house 

 mouse, Norway rat, cottontail, dog. The 

 golden hamster has been infected experi- 

 mentally. A few human infections with 

 Enceplialitozoon have been reported, but 

 they were all actually Toxoplasma. 



Location : Encephalitozoon occurs in- 

 tracellularly in the brain, kidneys, periton- 

 eal exudate, liver, spleen and other organs. 



