238 



THE TELOSPORASroA AND THE COCCIDIA PROPER 



here contain about 12 merozoites. Sexual 

 stages appear to be produced in both loca- 

 tions. The oocysts produced in the epithe- 

 lial cells during the acute phase are 

 unsporulated when passed in the feces. 

 They appear 6 to 7 days after infection. 

 The oocysts produced in the subepithelial 

 cells are sporulated when passed. A 

 number of unanswered questions are raised 

 by this account, and the whole life cycle 

 deserves re-investigation. 



Pathogenesis : This species is mark- 

 edly pathogenic for both cats and dogs. 

 Its effects on the dog, cat and fox were 

 studied by Lee (1934). Puppies and kittens 

 are most seriously affected, while adults 

 are usually carriers, having developed an 

 immunity following earlier infection. 



The first signs usually begin 4 to 6 

 days after infection. Their severity de- 

 pends on the degree of infection. In 

 severe cases, catarrhal or bloody diar- 

 rhea, rapid emaciation and anemia occur. 

 Affected animals are weak, depressed and 

 lose their appetite. There may be a rise 

 in temperature or muscular tremors of 

 the hind legs. If the animal survives the 

 acute phase, the dysentery is replaced by 

 mucous stools for 2 to 4 days and the 

 other signs subside, disappearing 7 to 10 

 days after their onset. Recovered animals 

 may continue to shed oocysts for a time. 



from those of /. bigemina, and a number 

 of investigators believe that they are the 

 same species (Elsdon-Dew and Freedman, 

 1953; Routh, McCroan and Hames, 1955; 

 Becker, 1956). Cross-transmission ex- 

 periments are needed to determine whether 

 they are. 



ISOSPORA FEUS 

 WENYON, 1923 



Synonyms : Isospora call, Coccidium 

 bigeniinuni var. cati, Lucetina cati, 

 Lucetina fells. 



Hosts : Dog, cat, lion and possibly 

 other carnivores. 



Location : Small intestine, some- 

 times cecum, occasionally colon. 



Geographic Distribution : Worldwide. 



Prevalence : This species in common 

 in dogs and cats. Gassner (1940) found it 

 in 6% of 320 dogs in Colorado. Catcott 

 (1946) found it in 3. 5% of 113 dogs in Ohio. 

 Choquette and Gelinas (1950) found it in 9% 

 of 155 dogs in Montreal. Hitchcock (1953) 

 found it in 75% of 147 kittens in Michigan. 

 Alves da Cruz, de Sousa and Cabral (1952) 

 found it in 10% of 40 stray cats in Lisbon, 

 Portugal. 



In severe cases, hemorrhagic enter- 

 itis is present thruout the small intestine; 

 it is most severe in the lower ileum and 

 becomes progressively less so anteriorly. 

 Petechiae are present in light infections, 

 and diffuse hemorrhages in more severe 

 ones. There may be ulcers in addition. 

 The mucosa is thickened, and there may 

 be extensive desquamation. A circulating 

 eosinophilia may be present, and the para- 

 sitized region is infiltrated with eosino- 

 philes. 



Cross-Transmission : Lee (1934) 

 transmitted /. bigemina from the dog to 

 the cat and fox, but failed to infect rabbits 

 or guinea pigs with it. 



Remarks : The oocysts of /. honiinis 

 of man are apparently indistinguishable 



Morphology : The oocysts are ovoid, 

 32 to 53 by 26 to 43 ji with a mean of 43 

 by 33 jj. . The oocyst wall is smooth and 

 colorless, without a micropyle. An oocyst 

 polar granule and residuum are absent. 

 The sporocysts are ellipsoidal, 20 to 27 

 by 18 to 21 /i. A sporocyst residuum is 

 present. The sporozoites are 10 to 15;^ 

 long. The sporulation time is 3 days or 

 less. 



Life Cycle : The life cycle of /. fells 

 in experimentally infected kittens was des- 

 cribed in detail by Hitchcock (1955) and 

 Lickfeld (1959). It is similar in dogs. 

 The parasites are found above or beside 

 the host cell nuclei of the epithelial cells 

 of the villi and sometimes in the subepi- 

 thelial tissues. There are 2 asexual gen- 

 erations. The first generation schizonts 



