222 



THE TELOSPORASIDA AND THE COCCIDLA PROPER 



immune without suffering disease. While 

 this system often works well, failures 

 have been encountered too often to justify 

 recommending its general use at present. 



EIMERIA MELEAGRIDIS 

 TYZZER, 1927 



Hosts : Domestic and wild turkey. 



Altho Steward (1947) and Gill (1954) 

 claimed to have transmitted this species 

 experimentally to the chicken, Tyzzer 

 (1929) was unable to transmit it to the 

 chicken, ring-necked pheasant or bob- 

 white quail, Hawkins (1952) was unable to 

 transmit it to the bobwhite quail or Hun- 

 garian partridge, and Moore, Brown and 

 Carter (cited by Moore, 1954) and Clark- 

 son (1959a) were unable to transmit it to 

 the chicken. 



Location : The first generation schi- 

 zonts, which are relatively few in number, 

 are found only in the small intestine a 

 short distance on either side of the yolk 

 stalk. They lie below the host cell nuclei 

 in the epithelial cells, mostly in those 

 near the base of the villi but not in the 

 deep glands. 



The second generation schizonts 

 occur in the cecum, where they lie above 

 the host cell nuclei in the epithelial cells 

 of the tips of the villi. 



The sexual stages are found in the 

 cecum, rectum and, to a slight extent, 

 ileum. They lie above the host cell nuclei 

 deep in the glands of the cecum as well as 

 in the surface epithelium (Clarkson, 1959a). 



Geographic Distribution : Worldwide. 



Prevalence : Common. Kozicky 

 (1948) found "E. meleagridis" in the drop- 

 pings of 40% of 95 wild turkeys in Penn- 

 sylvania. 



Morphology : This species was first 

 described by Tyzzer (1927). The oocysts 

 are ellipsoidal, smooth, 19 to 31 by 14 to 

 23 ^x with a mean of 24 by 17 (i. The 

 oocysts measured by Clarkson (1959a) 



were 22.3 + 2.3 by 16. 25 t 1.23fi. A 

 micropyle is absent. One or 2 oocyst 

 polar granules are present. An oocyst 

 residuum is absent. The sporocysts are 

 ovoid, with a Stieda body. A sporocyst 

 residuum is present. The sporulation 

 time is 1 day. Edgar (1955) found some 

 sporulated oocysts as early as 15 hours 

 at 28 C. 



Life Cycle : Hawkins (1952) and 

 Clarkson (1959a) described the life cycle, 

 the latter using a strain which he had de- 

 rived from a single oocyst. The first 

 generation schizonts are present 2 to 5 

 days after infection, being found in great- 

 est numbers at 60 hours. They measure 

 20 by 15/1 and contain 50 to 100 mero- 

 zoites measuring 7 by 1. 5(i. The second 

 generation schizonts first appear 60 hours 

 after infection, and mature ones are pres- 

 ent after 70 hours; they are seen in great- 

 est numbers at 84 hours. They are about 

 9 (i in diameter and contain 8 to 16 mero- 

 zoites which measure 10 by 2;i. Hawkins 

 stated that there may be a third asexual 

 generation, but that most of the second 

 generation merozoites develop into sexual 

 stages; Clarkson did not describe third 

 generation schizonts. 



Macrogametes and microgametocytes 

 appear at 91 hours and become mature 9 

 days after infection. They measure about 

 18 by 13jLt. The microgametes are bi- 

 flagellate. 



According to Hawkins, oocysts appear 

 in the feces 5 days after infection; Clarkson 

 found that the prepatent period was 108 to 

 112 hours. 



Pathogenesis : This species is prac- 

 tically non-pathogenic. Hawkins (1952) 

 observed only a slight drop in weight in 

 poults experimentally infected with 

 400,000 to 1 million sporulated oocysts. 

 Moore and Brown (1951) infected poults 

 with "enormous numbers" of fresh, spor- 

 ulated oocysts without producing clinical 

 evidence of coccidiosis. Clarkson (1959a) 

 found that doses of up to 1 million oocysts 

 produced no signs of disease in 2-week- 

 old poults. 



