THE TELOSPORASIDA AND THE COCCIDIA PROPER 



217 



A number of alkylidenediphenols, 

 which are diphenylmethane derivatives, 

 are effective against E. tenella, (Johnson, 

 Mussell and Dietzler, 1949, 1949a; 

 Groschke et al. , 1949). One of these, 

 Parabis-90, is 2, 2'-methylene-bis-4- 

 chlorophenol. It is used in the starter 

 feed at a concentration of 0. 15%, and 

 later on, when the chicks are 6 to 8 weeks 

 old, in the grower feed at a concentration 

 of 0. 12%. These compounds are also coc- 

 cidiostatic and will not cure coccidiosis 

 once signs of the disease have appeared. 

 They appear to act primarily against the 

 earlier endogenous stages but not against 

 the sporozoites, and birds which are ex- 

 posed while getting the drug become im- 

 mune. They do not appear to harm 

 chickens when fed at the recommended 

 levels. 



A diphenyl disulfide derivative which 

 has been widely used as a coccidiostat 

 against both E. tenella and E. necatrix 

 is nitrophenide (Megasul). It is 3, 3'-di- 

 nitrodiphenyldisulfide (Waletzky, Hughes 

 and Brandt, 1949; Peterson and Hymas, 

 1950; Dickinson, Babcock and Osebold, 

 1951; Gardiner, Farr and Wehr, 1952; 

 Horton-Smith and Long, 1959). It is 

 mixed with the feed at the rate of 0. 025 to 

 0. 05%. It is coccidiostatic and will not 

 cure coccidiosis once signs of the disease 

 have appeared. It acts against both the 

 sporozoites and later stages, but is more 

 effective against the latter and especially 

 against the second generation schizonts. 

 Immunity does not appear to develop if 

 chickens are treated before infection, but 

 it does if treatment begins at the time of 

 infection or later. Nitrophenide is not 

 harmful if fed in therapeutic concentra- 

 tions. At higher doses Newberne and 

 McDougle (1956) found that it may cause 

 postural and locomotor disturbances, 

 lowered weight gains, liver degeneration 

 and bone marrow changes. 



Another coccidiostat is the diphenyl- 

 sulfide derivative, bithionol, or 2,2'- 

 dihydroxy-3, 3', 5, 5'-tetrachlorodiphenyl 

 sulfide. The commercial coccidiostat, 

 Trithiadol, is a mixture of 5 parts bithi- 

 onol and 1 part methiotriazamine. The 

 latter is 4, 6-diamino-l-(4-methylmer- 



captophenyl)-!, 2-dihydro-2, 2-dimethyl- 

 1, 3, 5-triazine. Bithionol is not only coc- 

 cidiostatic but also antibacterial and anti- 

 fungal. Methiotriazamine is coccidiostatic 

 at high concentrations and is also an active 

 antimalarial agent. In combination, these 

 drugs are effective against coccidia at 

 lower concentrations than when used alone. 

 A mixture containing 60% active ingredients 

 is fed in the feed at the rate of 2 pounds per 

 ton. The recommended use level is 0.05% 

 bithionol plus 0.01% methiotriazamine. It 

 is effective against E. tenella, E. necatrix, 

 E. maxima and E. acervulina. Chickens 

 fed it develop immunity to these coccidia. 

 McLoughlin and Chester (1959) found that 

 0. 06% Trithiadol gave relatively good pro- 

 tection from mortality due to E. tenella. 

 It was not as good as glycarbylamide and 

 nicarbazin but was about as effective as 

 nitrofurazone and Bifuran and somewhat 

 better than sulfaquinoxaline. Trithiadol 

 is not harmful to growing chickens when 

 fed at the recommended levels (Arnold 

 and Coulston, 1959). It does not appear 

 to affect egg production or egg shell color 

 or quality, but it does affect hatchability 

 to some extent and is not recommended 

 for use in laying mashes. 



Two nitrofurans are currently used 

 as coccidiostats. Nitrofurazone (5-nitro- 

 2-furaldehyde semicarbazone) was intro- 

 duced by Harwood and Stunz (1949, 1949a, 

 1950) and has been studied further by 

 Peterson and Hymas (1950), Gardiner and 

 Farr (1954), Horton-Smith and Long (1952, 

 1959) and McLoughlin and Chester (1959), 

 among others. It is mixed with the feed 

 at the rate of 0.011%. It is effective 

 against E. tenella and to a lesser extent 

 against E. necatrix and E. maxima. 

 Higher concentrations give better results 

 against the intestinal species. Nitrofur- 

 azone is coccidiostatic and will not cure 

 coccidiosis once signs of the disease have 

 appeared. It acts against the schizonts, 

 and birds infected while receiving the 

 drug develop immunity to reinfection. 



Nitrofurazone is not harmful if fed in 

 therapeutic amounts, but 0.04 to 0.05% in 

 the feed is definitely toxic, and an adverse 

 effect on the growth rate has been noted 

 even at 0.022% (Gardiner and Farr, 1954; 



