216 



THE TELOSPORASIDA AND THE COCCIDIA PROPER 



drinking water at 0. 2%, and sodium sulfa- 

 quinoxaline at about 0.04% (see Grumbles, 

 el al. , 1949; Farr, 1949; Dickinson, 1949; 

 Kendall and McCuUough, 1952; Peterson 

 and Munro, 1949; Peterson and Hymas, 

 1950; Davies and Kendall, 1954; Bankow- 

 ski, 1950; Horton-Smith and Long, 1959; 

 and McLoughlin and Chester, 1959 for re- 

 views and further information). 



The sulfonamides are in general more 

 effective against the schizonts and mero- 

 zoites than against the gametes, gameto- 

 cytes and sporozoites. Bankowski (1950) 

 found that 0. 5% sulfaguanidine was coccid- 

 iostatic against the first generation schi- 

 zonts of E. tenella but that 2% sulfaguan- 

 idine was required to kill the second gen- 

 eration schizonts in the lamina propria 

 and even this concentration had no effect 

 on the sporozoites. He concluded that 

 this drug must act against the merozoites 

 in the lumen of the ceca, since 0. 5% is 

 the usual concentration in the feed. Ken- 

 dall and McCullough (1952) found that 0. 25 

 to 0. 375% sulfamethazine in the feed af- 

 fected the later stages in the life cycle, 

 but that 0. 5 to 1.0% was required to affect 

 the early stages. Farr and Wehr (1947) 

 found that 1% sulfamethazine almost com- 

 pletely destroyed the second generation 

 schizonts and their merozoites, somewhat 

 affected the first generation schizonts but 

 did not completely destroy them, and 

 either damaged or destroyed the young 

 gametes. It did not injure the larger gam- 

 etes, oocysts or sporozoites. The action 

 of sulfaquinoxaline is similar. 



All of the sulfonamides are coccidio- 

 static rather than truly curative. None 

 will cure coccidiosis once signs of dis- 

 ease have appeared. When fed continu- 

 ously in the feed, they abort the disease. 

 Sulfaquinoxaline will protect birds when 

 given as late as 4 days after experimental 

 infection. Since the sporozoites are not 

 affected, they invade the intestinal cells 

 and stimulate the development of immun- 

 ity. However, if too much of a sulfona- 

 mide is given, immunity will not develop. 

 Thus, Kendall and McCullough (1952) 

 found that when 0. 25 to 0. 375% sulfameth- 

 azine was given in the feed, immunity de- 

 veloped, but when the concentration was 

 raised to 0. 5 to 1. 0% it did not. 



When given in the recommended 

 amounts, the sulfonamides are not gener- 

 ally harmful. Sulfaquinoxaline does not 

 depress the growth rate of chicks when fed 

 for a long period at rates of 0.01 to 0.02%, 

 but 0.03% gives variable results and higher 

 concentrations are usually toxic. Dela- 

 plane and Milliff (1948) found that when 

 0. 05% sulfaquinoxaline was fed continu- 

 ously to pullets in egg production, signs 

 of poisoning appeared and some birds died. 

 They found greyish-white nodules in the 

 spleens of most birds and in the livers, 

 kidneys, hearts and lungs of some. There 

 were also hemorrhages beneath the skin of 

 the legs and in the combs. Davies and 

 Kendall (1953) found that 0.0645% sodium 

 sulfaquinoxaline in the drinking water was 

 toxic to chickens when fed for as short a 

 period as 5 days. The principal lesions 

 were hemorrhages, especially in the 

 spleen, and accumulation of fluid in the 

 peritoneal cavity. On the other hand, 

 Cuckler and Ott (1955) reported that the 

 continuous administration of 0. 05% sulfa- 

 quinoxaline in the feed or of 0.025% in the 

 water for as long as 12 weeks had no ad- 

 verse effects on chickens. The blood 

 clotting time was prolonged and the pro- 

 thrombin time increased slightly by feeding 

 0.4% sulfaquinoxaline for 3 to 12 weeks. 



Several organic arsenic compounds 

 have been found effective against E. 

 tenella, but not against the other species 

 (Morehouse and Mayfield, 1946; Goble, 

 1949). All are derivatives of phenylarsonic 

 acid. All are coccidiostatic, and none will 

 cure coccidiosis once signs of disease have 

 appeared. The most widely used of these 

 is perhaps 3-nitro-4-hydroxyphenylarsonic 

 acid, which is generally administered in 



the feed at a concentration of 0. 01' 



It 



apparently acts against the earlier endog- 

 enous stages, but not against the sporo- 

 zoites, and birds which are exposed while 

 under prophylactic treatment become im- 

 mune. At the recommended dosage it has 

 no harmful effect on the host but is actually 

 a growth stimulant. A mixture of this 

 compound and N^-acetyl-N'-(4-nitrophenyl) 

 suKanilamide is sold under the name Ni- 

 trosal to suppress both cecal and intestinal 

 coccidiosis. Another active organic ar- 

 senic compound is arsanilic acid. 



