322 



SARCOCYSTIS, TOXOPLASMA AND RELATED PROTOZOA 



around the cysts followed by necrosis and 

 calcification in swine, but saw no such re- 

 action in cattle. Spindler, Zimmerman 

 and Jaquette (1946) found that pigs with 40 

 or more cysts per gram of diaphragm 

 were unthrifty and showed signs of mus- 

 cular stiffness. 



Gastrointestinal signs and lesions 

 may occur after ingestion of the cysts. 

 Scott (1943) reported extensive destruction 

 of the epithelium together with a bloody 

 serous exudate in the ileum of young rats 

 fed sarcocysts from sheep, and the an- 

 imals appeared ill and disinclined to move 

 about. Spindler, Zimmerman and Jaquette 

 (1946) observed vomiting, diarrhea, in- 

 appetence and temporary posterior paraly- 

 sis in pigs fed infected muscles, urine or 

 feces. 



The cysts contain a powerful endo- 

 toxin known as sarcocystin, which is 

 highly toxic for rabbits, mice, and spar- 

 rows, but probably less toxic for rats, 

 sheep and some other animals. Sarco- 

 cystin acts on the central nervous system 

 and also affects the heart, adrenal glands, 

 liver and intestinal wall. It is filtrable, 

 and is destroyed by heat. Small amounts 

 cause a febrile reaction in the rabbit, 

 while large amounts produce collapse, 

 severe diarrhea and death. According to 

 Sato (1926), the intravenous minimum 

 lethal dose for the rabbit of the extract 

 from S. f us if or mis from the ox is 0.05 

 mg per kilogram body weight. 



Immunity : Animals can be immunized 

 against sarcocystin by repeated injections 

 of untreated or formalin-treated toxin. 

 The serum of immunized animals will pro- 

 tect other animals against the toxin. 



The close relationship between Sar- 

 cocystis and ToxoplasDui is attested by the 

 fact that both react with cytoplasm -modify- 

 ing antibody in the Sabin-Feldman dye test 

 (described below under Toxoplasma). As 

 a matter of fact, cross reactions between 

 the two are not uncommon. Muhlpfordt 

 (1951) and Awad and Lainson (1954) found 

 that the sera of laboratory animals fed 

 S. lenella from sheep reacted positively 

 to the dye test with Toxoplasma tropho- 

 zoites. The sera of sheep naturally in- 



fected with S. lenella also gave positive 

 reactions. Awad (1954) went a step fur- 

 ther, and developed a modified dye test for 

 Toxoplasma, using S. lenella trophozoites. 

 These trophozoites gave positive results 

 with the sera of animals infected with either 

 Toxoplasma or Sarcocystis. 



Epidemiology : Seasonal infection 

 during the late spring, summer and early 

 fall has been reported in sheep, swine and 

 horses in the temperate zone (Scott, 1943). 

 Repeated infections of sheep in successive 

 seasons were reported by Scott (1943). He 

 had the impression that the older the an- 

 imals, the more heavily they were para- 

 sitized. 



Diagnosis : Because of the absence of 

 recognizable signs, Sarcocyslis infections 

 are almost always diagnosed after death. 

 The larger cysts are easily seen with the 

 naked eye, and the small ones can be found 

 by histologic examination. 



Cultivation : Sarcocystis has not been 

 cultivated, unless the claims of Spindler 

 and Zimmerman (1945) and Ciesla (1950) 

 are accepted. 



Treatment : None known. 



Prevention and Control : Since Sar- 

 cocystis infections are acquired thru fecal 

 contamination of food or drink, infections 

 can be prevented by measures designed to 

 prevent such contamination. Sanitation 

 and good management should be effective. 



SARCOCYSTIS MIESCHERIANA 

 (KUHN, 1865) LANKESTER, 1882 



Synonyms : Synchytrium niiescheri- 

 anum . 



Host : Pig. 



Location : Striated and heart muscles. 



Geographic Distribution : Worldwide. 



Prevalence : This species is ex- 

 tremely common thruout the world, having 

 been reported in as high as 98. 5% of pigs 

 examined. Alicata (1932) found it in 75% 



