THE TELOSPORASIDA AND THE COCCIDIA PROPER 



179 



Since the sulfonamides are generally 

 only partially effective, preventive mea- 

 sures are more important than curative 

 ones. 



Prevention : Sanitation and isolation 

 are effective in preventing coccidiosis. 

 Beef calves should be dropped and kept on 

 clean, well drained pastures. Overstock- 

 ing and crowding should be avoided. Feed 

 and water containers should be high enough 

 to prevent fecal contamination. Feed lots 

 should be kept dry and should be cleaned 

 as often as possible. Concrete or small 

 gravel are preferable to dirt. 



Dairy calves should be isolated within 

 24 hours after birth and kept separately. 

 Individual box stalls which are cleaned 

 daily may be used. Slat-bottom pens are 

 also effective and require less cleaning. 

 Allen and Duffee (1958) described a simple, 

 raised, wooden home-made stall with a 4 

 by 2-1/2 foot slatted floor in which dairy 

 calves can be raised separately for the 

 first 3 months. Davis (1949) and Davis 

 and Bowman (1952) described a 5 x 10 x 3 

 foot outdoor portable pen which can be 

 moved to a fresh site once a week and thus 

 eliminates the need for cleaning. It is 

 made primarily of net wire and 1x4 lum- 

 ber, with a removable roof and siding at 

 one end. The pens should not be returned 

 to the same ground for a year. 



These methods will not eliminate all 

 coccidia, but they will prevent the calves 

 from picking up enough oocysts to harm 

 them. In addition, they will greatly reduce 

 lice, helminth parasites, pneumonia, 

 white scours and other diseases. 



The unsporulated oocysts of E. zurnii 

 are killed by sunlight in 4 hours or by dry- 

 ing at 25% relative humidity or below in 

 several days. They are not harmed by 

 freezing at -7 to -8° C for as long as 2 

 months, and half of them survive as long 

 as 5 months; at -30 °C, however, only 5% 

 survive 1 day. The oocysts are killed by 

 10"^ M mercuric chloride, 0.05 M phenol, 

 0. 25 M formaldehyde, 1. 25% sodium hypo- 

 chlorite, or 0. 5% cresol (Marquardt, Sen- 

 ger and Seghetti, 1960). 



EIMERIA AHSATA 

 HONESS, 1942 emend. 



Synonym : Eimeria ah-sa-ia Honess, 

 1942. 



Hosts : Sheep, Rocky Mountain big- 

 horn sheep. 



Location : Unknown. Oocysts found 

 in feces. 



Geographic Distribution : North Amer- 

 ica (Wyoming, Alabama). 



Prevalence : Unknown. 



Morphology : The oocysts are ellip- 

 soidal and faint pink. The oocyst wall is 

 faint straw-colored and lined by a mem- 

 brane. A micropyle and micropylar cap 

 are present. Oocysts from the bighorn 

 sheep are 30 to 40 by 20 to 30|Lt with a 

 mean of 32. 7 by 23. 7 |j, ; their length- width 

 ratio is 1.1 to 1.8 with a mean of 1 . 40; 

 the micropylar cap is 0. 4 to 4. 2 jn high and 

 2. 1 to 12. 5)n wide with a mean of 2. 1 by 

 l.^li. Oocysts from domestic sheep are 

 29 to 37 by 17 to 28 ^i with a mean of 33.4 

 by 22.6ju; their length-width ratio is 1.2 

 to 1 . 8 with a mean of 1 . 48; the micropylar 

 cap is 1.7 to 4. 2/i high and 5. 9 to 13. 4jj, 

 wide with a mean of 3. by 8. 4 |_i . An 

 oocyst residuum is present in some oocysts. 

 Oocyst polar (?) granules are almost al- 

 ways present. The sporocysts are 15.4 

 by 7. 8jj. and have a sporocyst residuum. 



This species is difficult to distinguish 

 from E. arlouigi, and Morgan and Hawkins 

 (1952) and Lotze (1953) considered it of 

 doubtful validity. However, Smith, Davis 

 and Bowman (1960) rediscovered it in Ala- 

 bama and confirmed its distinctiveness. 



Life Cycle : Unknown. The prepatent 

 period is 18 to 20 days according to Smith, 

 Davis and Bowman (1960). 



Pathogenesis : Smith, Davis and Bow- 

 man (1960) considered this the most patho- 

 genic of all sheep coccidia. They produced 

 fatal infections in 4 out of 9 lambs 1 to 3 

 months old by feeding 100, 000 oocysts. 



