THE TELOSPORASIDA AND THE COCCIDIA PROPER 



237 



Cross-Transmission Studies : Biester 

 and Murray (1934) and Biester (1934) re- 

 ported that attempts to transmit /. sids 

 to guinea pigs, rats, and dogs were un- 

 successful. 



ISOSPORA ALMATAENSIS 

 PAICHUK, 1953 



Host : Pig. 



Location : Unknown. Oocysts found 

 in feces. 



Geographic Distribution : USSR 

 (Kazakhstan). 



Prevalence : Unknown. 



Morphology : This species was des- 

 cribed by Paichuk (1953). The oocysts 

 are short-oval, subspherical or spherical, 

 and grey. The short-oval forms are 25 

 to 32 by 23 to 29 jj, with a mean of 27. 9 by 

 26. \i ; the spherical forms are 26 to 32 [i 

 in diameter with a mean of 27. 7 /j. . The 

 oocyst wall is smooth, bright yellow, "i^i 

 thick, and composed of 3 layers. A mi- 

 cropyle is apparently absent. The oocysts 

 sometimes have 2 sporoblasts when 

 passed. Oocyst polar granules are pres- 

 ent. An oocyst residuum is absent. The 

 sporocysts are oval or ovoid with a 

 pointed end, 12 to 19 by 9 to 12 /i with a 

 mean of 15.5 by 10. 8 /i . A sporocyst 

 residuum is present. The sporozoites are 

 short-oval, 6 by 4jj.. The sporulation 

 time is 5 days. 



Life Cycle : Unknown. 



Pathogenesis : Unknown. 



ISOSPORA BIGEMINA 

 (STILES, 1891) 

 LUHE, 1906 



Synonyms : Coccidium bigeminum, 

 Liicetina bigemina. 



Hosts : Dog, cat, fox, polecat (Pu- 

 toriiis foetidus), mink (Mustela vison), 

 man (?). 



Location: Thruout small intestine. 



Geographic Distribution : Worldwide. 



Prevalence : This species is quite 

 common in dogs and cats. Gassner (1940) 

 found it in 74% of 320 dogs in Colorado. 

 Catcott (1946) found it in 3% of 113 dogs 

 in Ohio. Choquette and Gelinas (1950) 

 found it in 2% of 155 dogs in Montreal. 

 Ehrenford (1953) found it in 0.7% of 377 

 dogs in Indiana and other midwestern 

 states. Hitchcock (1953) found it in 1% of 

 147 kittens in Michigan. Levine (1948) 

 reviewed reports of this species in Mus- 

 telidae. 



Morphology: The oocysts are very 

 thin-walled, spherical to ellipsoidal when 

 unsporulated, but with the wall stretched 

 around the sporocysts and usually con- 

 stricted somewhat between them when 

 sporulated. The oocyst wall is smooth, 

 colorless, and composed of a single layer. 

 Two sizes of oocyst have been reported. 

 The larger ones measure 18 to 20 by 14 

 to 16 |i, and the smaller, more common 

 ones 10 to 14 by 7 to 9 ^t. Micropyle, 

 oocyst polar granule and oocyst residuum 

 are absent. The sporocysts are ellip- 

 soidal, 7. 5 to 9 by 5 to 7 |:x, without a 

 Stieda body. A sporocyst residuum is 

 present. The oocysts are sporulated 

 when passed. The oocyst wall is often 

 ruptured so that the sporocysts are found 

 free in the feces. In acute infections, the 

 oocysts may be unsporulated when passed; 

 their sporulation time is about 4 days. 



Life Cycle : The life cycle of this 

 species has been studied by Wenyon (1926a) 

 and Wenyon and Sheather (1925). The 

 endogenous stages occur thruout the small 

 intestine. Altho the course of infection has 

 not been followed consecutively in a series 

 of experimentally infected animals, it ap- 

 pears that the epithelial cells are invaded 

 first, followed later on by the subepithelial 

 cells. At any rate, Wenyon and Sheather 

 (1925) found coccidia only in the epithelial 

 cells of a dog killed during the acute phase 

 of the infection. The schizonts of this 

 stage contain 8 merozoites. Later on, the 

 coccidia are found in the subepithelial 

 cells and cores of the villi. The schizonts 



