178 



THE TELOSPORASIDA AND THE COCCIDIA PROPER 



signs, gross lesions at necropsy and mi- 

 croscopic examination of scrapings of the 

 intestinal mucosa and of feces. Diarrhea 

 or dysentery accompanied by anemia, 

 weakness, emaciation and inappetance are 

 suggestive of coccidiosis in calves. Sec- 

 ondary pneumonia is often present. The 

 lesions found at necropsy have already 

 been described. 



Microscopic examination is necessary 

 to determine whether the lesions are due 

 to coccidia or to some other agent. How- 

 ever, diagnoses will often be missed if 

 one relies only on finding oocysts in the 

 feces. There may be none there at all in 

 the acute stage of zurnii coccidiosis. 

 Similarly, the mere presence of oocysts 

 in the feces is not proof that coccidiosis 

 is present; it may be coccidiasis. To be 

 sure of a diagnosis, scrapings should be 

 made from the affected intestinal mucosa 

 and examined under the microscope. It is 

 not enough to look for oocysts, however, 

 but schizonts, merozoites and young gam- 

 etes should be recognized. 



Treatment: A number of investigators 

 (Boughton, 1943; Boughton and Davis, 

 1943; Davis and Bowman,- 1952, 1954; 

 Hammond et al . . 1956; Senger et al. . 1959) 

 have found that the sulfonamides have some 

 value against bovine coccidiosis. 



Other types of compounds which are 

 used in avian coccidiosis are unsatisfac- 

 tory. For example, Hammond el al. (1957) 

 found that nicarbazin was effective in pre- 

 venting experimental coccidiosis due to 

 E. bovis in calves only at doses which 

 were toxic to the animals. Gardner and 

 Wittorff (1955) found that 0. 1 to 0. 3% 

 furacin in the ration was toxic to dairy 

 calves, causing nervous signs and reducing 

 or preventing weight gains. Even 0.01% 

 of the drug had some toxic effect. It in- 

 jures the myelin sheaths and causes cere- 

 bral damage. 



Gasparini, Roncalli and Ruffini (1958) 

 claimed that drenching with 4 g per 100 kg 

 ammonium sulfate plus 2 ml lactic acid in 

 a liter of milk twice a day for 4 consecu- 

 tive days cured coccidiosis due to E. zurnii 

 in 2 herds of cattle in Italy, They believed 



that the ammonium sulfate worked by re- 

 leasing ammonia, and added the lactic acid 

 to prevent release from taking place in the 

 stomach. However, their work was im- 

 properly controlled, and the efficacy of 

 this compound remains to be determined. 



Sulfamethazine and sulfamerazine ap- 

 pear to be better than sulfaquinoxaline or 

 other suKonamides. They are only par- 

 tially effective, however. They do not 

 prevent the diarrhea, but they do reduce 

 the severity of the disease. Thus, Davis 

 and Bowman (1954) found that sulfametha- 

 zine reduced the severity of experimental 

 infections with E. ziirnii or mixed species 

 in calves and that treated calves gained 

 slightly more weight than the controls. 

 Drug treatment was started before infec- 

 tion, and no immunity to subsequent expo- 

 sures was produced. Hammond cl al. 

 (1956) found that sulfamerazine or sulfa- 

 quinoxaline, given to calves at the rate of 

 0. 143 g per kg body weight for 2 days and 

 0. 072 g per kg for 2 more days, decreased 

 the severity of coccidiosis due to E. bovis 

 if they were administered between 13 and 

 17 days after experimental infection. 

 They were not effective earlier or later 

 than this. The drugs presumably act on 

 the merozoites after their release from 

 the schizonts. Senger el al. (1959) found 

 that a mixture of equal parts sulfamerazine 

 and sulfamethazine given by mouth at the 

 rate of 213, 143 and 70 mg per kg body 

 weight 13, 14 and 15 days, respectively, 

 after inoculation reduced the severity of 

 the disease and did not interfere with the 

 development of immunity. 



Hammond el al. (1959) found that a 

 single treatment with 0. 215 g per kg sulfa- 

 methazine or sulfabromomethazine 13 days 

 after experimental inoculation with E. bovis 

 effectively controlled coccidiosis. Admin- 

 istration of either compound on alternate 

 days at the rate of 0.0215 g per kg for as 

 short a period as 10 to 18 days after inoc- 

 ulation also effectively controlled coccid- 

 iosis, while in 1 experiment treatment at 

 this rate 12 and 14 days after inoculation 

 suppressed the disease. This treatment 

 did not interfere with the development of 

 immunity. 



