THE TELOSPORASIDA AND THE COCCIDIA PROPER 



219 



According to Rogers eL al. (1960), 0.0125% 

 amprolium in the feed is effective against 

 E. tenella, E. necatrix and £. acervuliiia. 

 It is a thiamine antagonist, and 0. 003% 

 thiamine in the feed markedly decreased 

 its activity against coccidia. Another 

 name for amprolium is mepyrium, the 

 discovery of which was announced by 

 Aries (1960). 



According to Rogers et al. (1960), 

 many other l-(2-alkyl-4-amino-5-pyri- 

 midinylmethyl)-alkyl pyridinium salts have 

 marked prophylactic activity in coccidiosis 

 of poultry. Analogous 3-thiazolium com- 

 pounds are also effective. 



The imidazole derivative, glycarbyla- 

 mide (4, 5-imidazoledicarboxamide) was 

 introduced as a coccidiostat by Cuckler 

 et al. (1958). It is fed in a concentration 

 of 0. 003% in the feed. It is effective 

 against E. tenella, E. necatrix and E. 

 acervulina, but Horton-Smith and Long 

 (1959a) found that it is inferior to sulfa- 

 quinoxaline against the last. McLoughlin 

 and Chester (1959) found that it is about 

 as effective as nicarbazin against E. 

 tenella, and more effective than nitrofura- 

 zone, Bifuran, sulfaquinoxaline or Trithi- 

 adol. 



Glycarbylamide is coccidiostatic, and 

 will not cure coccidiosis once signs of the 

 disease have appeared. It acts against the 

 stages prior to the second generation 

 schizonts, and birds which are infected 

 while receiving the drug develop immunity 

 to reinfection. It is apparently non-toxic 

 when fed at the recommended level. 



Several benzamide derivatives are 

 effective coccidiostats. Morehouse and 

 McGuire (1957, 1959) found that 3, 5-di- 

 nitrobenzamide and several aliphatic N- 

 substituted derivatives are effective 

 against E. tenella and somewhat less ef- 

 fective against E. necatrix. They found 

 that Unistat, a "coccidiostatic growth 

 stimulant" mixture containing 30% N"*- 

 acetyl-N^-(4-nitrophenyl) sulfanilamide, 

 25% 3, 5-dinitrobenzamide and 5% 3-nitro- 

 4-hydroxyphenylarsonic acid in an inert 

 carrier, when fed at a concentration of 

 0. 1% in the feed, prevented death and 



permitted normal or near normal weight 

 gains in chicks infected with potentially 

 lethal doses of E. tenella, E. necatrix 

 and E. acervulina. 



Another benzamide derivative is 

 zoalene (3, 5-dinitro-o-toluamide). Hymas, 

 Stevenson and Shaver (1960) reported that 

 it prevents mortality and weight losses 

 from infections with E. tenella, E. neca- 

 trix, E. acervulina, E. maxima and E. 

 brunetti when fed continuously in the 

 ration of chicks at levels ranging from 

 0.0025 to 0.015%. They recommended a 

 level of 0. 0125% for broilers and lower 

 levels for replacement pullets. This com- 

 pound is most effective against E. necatrix. 



The benzamide derivatives are coc- 

 cidiostatic and will not cure the disease 

 once signs have appeared. Birds which 

 are infected while receiving them develop 

 immunity to reinfection. 



Hemorrhage is an important cause of 

 death from cecal coccidiosis, and its con- 

 trol will ameliorate the disease. Harms 

 and Tugwell (1956) and Tugwell, Stephens 

 and Harms (1957) found that the vitamin K 

 activity of alfalfa meal or menadione so- 

 dium bisulfite complex (Klotogen F) pre- 

 vented deaths from cecal coccidiosis in 

 birds on a basic vitamin K-deficient diet. 

 Otto et al. (1958) confirmed their work, 

 finding that 1.0 g of the water soluble 

 menadione sodium bisulfite complex per 

 ton of feed was just as effective as 3 g per 

 ton of menadione. 



Sulfonamides and other coccidiostats 

 have been mixed in poultry feed for so 

 many years that it was inevitable that drug 

 resistant strains of coccidia would develop. 

 The first report of this was by Waletzky, 

 Neal and Hable (1954), who found that a 

 field strain of E. tenella from a Delaware 

 broiler flock was more than 40 times as 

 resistant to sulfaquinoxaline and 5 times 

 as resistant to sulfamethazine as ordinary 

 strains. It was unaffected by 1.0% sulfa- 

 quinoxaline in the feed. Cuckler and 

 Malanga (1955) studied 40 field strains of 

 allegedly drug-resistant cecal or mixed 

 intestinal and cecal coccidia from chick- 

 ens. They found that 43% were resistant 



