346 PARASITES OF THE DOMESTIC ANIMALS 



enlargement of these organs nor abnormal appearance of their contents. 

 Not infrequently the enteritis involves the entire length of the intestines. 

 For a positive diagnosis microscopical examination of the intestinal 

 contents or of the sectioned intestinal wall is necessary. Spreads of 

 scrapings from the cecal mucosa examined under the microscope will 

 reveal epithelial cells much distended by the development of the par- 

 asites within them. It is as a result of this invasion that the cells finally 

 break down and separate from the underlying stroma to become a part 

 of the pasty catarrhal exudate which characterizes the fecal discharge. 



Infection. — Though the fatalities are usually among the young 

 chicks, the coccidian which causes the disease may be found in chickens 

 of all ages and it may be spread from this source. Infection is by food 

 and ingested soil or water contaminated by droppings which contain 

 the cysts. It has been demonstrated that the cysts may remain infective 

 for a year or more, therefore chickens may become infected if allowed 

 access to yards where those harboring the parasites were kept the year 

 previous. 



Control. — There are no drugs which have been found to be of value 

 in treating the disease, therefore control is the essential consideration in 

 contending with it. Morse states (Bureau of Animal Industry Cir- 

 cular No. 128, 1908) that this must begin with the eggs used for hatching. 

 "These," he writes, "should be thoroughly and antiseptically cleaned 

 by wiping in ninety-five per cent, alcohol. If artificial incubation is 

 used (and in this method lies the great hope of success), the incubator, 

 if used before, should, previous to recei%'ing the eggs, be carefully washed 

 with antiseptic solutions and exposed to the sun. The egg tray should 

 be scalded or flamed. The floor of the nursery should be movable, so 

 that it may be taken out and sterilized, and if made of burlap the old 

 piece should be torn off and a new piece mounted on the sterilized frame. 

 The same precautions should be used with the brooders. The soil to 

 which the chicks have access should be well covered with lime, dug up, 

 and exposed to the drying effects of the sun and air. If natural in- 

 cubation is practiced the hen for a week or two before being set should 

 be treated with one-quarter to one-half grain doses of sulphate of iron 

 daily, with occasionally an active purgative, such as calomel, one grain, 

 or castor oil, one-half teaspoonful containing five to ten drops of tur- 

 pentine. The eggs, cleansed as directed above, should be placed in a 

 perfectly fresh nest, which may be sprinkled from time to time with a 

 little lime. After hatching, the hen with her chicks should be placed 

 upon ground that has been thoroughly sterilized, as described above, 

 and at least every few days moved to fresh ground which has been 

 treated in the same way and from which all chickens have been de- 

 barred." 



Further preventive measures are the removal of visibly sick chicks 



