206 



THE TEIOSPORASIDA AND THE COCCIDIA PROPER 



Geographic Distribution : North 

 America. 



Prevalence : Uncommon. 



Morphology : P. P. Levine (1942) 

 described this species, and Becker, Zim- 

 mermann and Pattillo (1955) made a bio- 

 metric study of its oocysts. The oocysts 

 are ovoid, smooth, 14 to 34 by 12 to 26 /j. 

 with a mean of 23 by 20 /i. A micropyle 

 is absent. An oocyst polar granule is 

 present. An oocyst residuum is absent. 

 The sporocysts are elongate ovoid, about 

 13 by 7. 5(1, with a Stieda body. A sporo- 

 cyst residuum is present. The sporulation 

 time is 1 to 2 days. Edgar (1955) found 

 infective oocysts as early as 18 hours at 

 24" C. 



Life Cycle : The life cycle of this 

 species was described by Boles and 

 Becker (1954). The sporozoites are liber- 

 ated in the intestine and invade the epithel- 

 ial cells of the villi. They round up to 

 become first generation schizonts, which 

 lie below the host cell nuclei on the sides 

 of the villi of the upper, middle and lower 

 small intestines. They are present 51 to 

 76 hours after infection, measure 30 by 

 20j^L, and contain approximately 200 first 

 generation merozoites when mature. 

 These invade other cells in the posterior 

 small intestine, rectum, tubular part of 

 the ceca and cloaca. They are found pri- 

 marily at the tips of the villi, and usually 

 lie below the host cell nuclei. They turn 

 into second generation schizonts, which 

 are present 4 days after infection. These 

 average 30 by 16/i and contain 50 to 60 

 merozoites. Small schizonts about 10 by 

 9/j. were also seen on the 4th day, but 

 their significance was not determined. 



The second generation merozoites in- 

 vade fresh cells in the lower small intes- 

 tine, ceca, rectum and cloaca and turn 

 into sexual stages. These first appear on 

 the 5th day and lie at the tips and sides of 

 the villi, either above the host cell nuclei 

 or on the basement membrane. The micro- 

 gametocytes have a multicentric appear- 

 ance, and are larger than the macroga- 

 metes, which measure about 25 by 22|:i. 

 The macrogametes contain eosinophilic 



plastic granules which later coalesce and 

 form the oocyst wall. 



The prepatent period is 5 days. 



Brackett and Bliznick (1952) found 

 that E. brunetti could produce a maximum 

 of 400,000 oocysts per oocyst fed. This 

 figure was obtained in 2- to 3-week-old 

 chickens fed 50 oocysts each. With larger 

 inocula, relatively fewer oocysts were ob- 

 tained. With inocula of 250, 1250, 6250, 

 20, 000 and 40, 000 oocysts, respectively, 

 150,000, 26,000, 7000, 800 and 400 oocysts 

 were produced per oocyst fed. 



Pathogenesis : E. briinelli is mark- 

 edly pathogenic, but its effects depend upon 

 the degree of infection. In light infections, 

 no gross lesions may be seen. In heavier 

 infections, Levine (1942) found that the gut 

 wall becomes thickened and a pink or blood- 

 tinged catarrhal exudate appears 4 or 5 

 days after experimental infection: the drop- 

 pings are quite fluid and contain blood- 

 tinged mucus and many mucus casts. The 

 birds become somewhat depressed. These 

 signs continue for 5 days and then subside 

 if the birds recover. 



In early or light infections, hemor- 

 rhagic, ladder-like streaks are present on 

 the mucosa of the lower intestine and rec- 

 tum. In heavy infections, a characteristic 

 necrotic enteritis appears. It may involve 

 the entire intestinal tract, but is more often 

 found in the lower small intestine, large 

 intestine and tubular part of the ceca. A 

 patchy or continuous, dry, caseous necrotic 

 membrane may line the intestine, and the 

 intestine may be filled with sloughed, ne- 

 crotic material. Circumscribed white 

 patches may be visible thru the serosa, 

 and there may even be intestinal perfora- 

 tion with resultant peritonitis. 



Boles and Becker (1954) did not ob- 

 serve the extensive coagulation necrosis 

 described by Levine (1942) in their experi- 

 mentally infected chicks, but the other 

 lesions were similar to those of his moder- 

 ately infected birds. The birds became 

 listless 82 hours after infection, and pe- 

 techial hemorrhages were found, mostly 

 in the lower small intestine but also in the 



