240 



THE TELOSPORASIDA AND THE CCXTCmiA PROPER 



Life Cycle : The endogenous stages 

 of /. rivolla are poorly known. They are 

 said to resemble those of /. Jelis but to 

 be smaller. They are found in the epithe- 

 lial cells and sometimes in the subepithe- 

 lial tissues of the small intestine. Oocyst 

 development ordinarily takes place out- 

 side the body, but occasionally occurs in 

 the subepithelial tissues. 



Pathogenesis : Altho experimental 

 studied on /. rivolla alone have apparently 

 not been carried out, it is presumably as 

 pathogenic as /. bigeiniiia and /. Jelis. 



Cross Transmission: Lee (1934) in- 

 fected a fox with /. rivolla from the dog. 



Fig. 31. 



B 



Sporulated oocysts of coccidia of 



dog and cat. A. Isospora blgem- 



iiia. B. Isospura rivulla. 



C. Isospoya felis. X 850. (From 



Becker, 1934, after Wenyoii, 1926, 



Protozoology) 



COCCIDIOSIS IN DOGS AND CATS 



Epidemiology : Coccidiosis is com- 

 mon in dogs and cats, and is a not infre- 

 quent cause of diarrhea and even death 

 in puppies and kittens. Crowding and 

 lack of sanitation promote its spread. 

 Coccidia sometimes seed a breeding ken- 

 nel, boarding kennel or veterinarian's 

 wards so heavily that most of the puppies 

 born or brought there become infected. 



Diagnosis : Coccidiosis can be diag- 

 nosed at necropsy by finding coccidia in 

 the intestinal lesions. It can be diagnosed 

 in affected animals by finding oocysts in 



association with diarrhea or dysentery. 

 However, care must be taken to differen- 

 tiate coccidiosis from coccidiasis, since 

 many animals may be shedding oocysts 

 without suffering from disease. Other 

 disease agents should be searched for and 

 found absent. The presence of a wave of 

 oocysts during and shortly after an attack 

 of enteritis and their marked diminution or 

 disappearance soon thereafter would sug- 

 gest that coccidia caused the attack. 



The oocysts of Isospora bigemina are 

 usually sporulated when they are passed 

 in the feces. They are often ruptured, 

 releasing the sporocysts. These are very 

 small, and will often be overlooked unless 

 the high dry power of the microscope is 

 used in making a fecal examination. In 

 addition, they resemble Cryptospuridium 

 oocysts and might be mistaken for them. 



Treatment : There is no good treat- 

 ment for coccidiosis in dogs and cats once 

 the signs of disease have appeared. All 

 the coccidiostatic agents on the market 

 are preventive rather than curative in 

 action. The fact that coccidiosis is a 

 self-limiting disease has often led to the 

 belief that some ineffective drug, admin- 

 istered at the time natural recovery was 

 due to begin, was responsible for the 

 cure. Uncontrolled studies on coccidiosis 

 therapy, such as that of Duberman (1960) 

 with nitrofurazone, are worse than use- 

 less, since they may lead to false con- 

 clusions regarding a drug's value. 



Craige (1949), a clinician with con- 

 siderable experience in handling canine 

 coccidiosis, considered treatment in an 

 unsatisfactory state. Sometimes the 

 animals would respond to sulfonamides, 

 but he had better success by combining a 

 sulfonamide with quinacrine, sulfocar- 

 bolates, tannin-yeast, iodine preparations, 

 etc. McGee (1950) used sulfamethazine. 

 Altman (1951) used chlortetracycline. 

 Supportive treatments such as these, and 

 particularly the use of antibiotics such as 

 chlortetracycline and oxytetracycline to 

 control secondary infections, may be 

 helpful even tho they do not act on the 

 coccidia themselves. 



