CHAPTER XXXI 



COCCIDIOSIS IN BIRDS AND MAMMALS 



By 



Justin Andrews 



The Johns Hopkins University School of Hygiene and 



PubHc Health 



METHODS 



Collection and Concentration of Oocysts. Coccidial oocysts may 

 be collected either from the feces of an infected animal or from 

 its intestine. If the material is obtained from either source when 

 the animal is at the height of its infection, it is not necessary to 

 undertake any very elaborate measures for concentration. The 

 feces or scrapings may be diluted with from ten to twenty volumes 

 of water, strained through several thicknesses of cheesecloth, and 

 gently centrifuged for two or three minutes. The sediment con- 

 tains oocysts in great numbers with a minimum of debris. 



If it is necessary to obtain a heavier concentration of oocysts 

 than the feces of the available infected animals can supply, the 

 stools may be treated as follows : The specimens collected should 

 each be examined by the simple smear method (see section on 

 Diagnosis) , and samples containing so few oocysts that it is diffi- 

 cult to find them by this method should be discarded. The stools 

 are diluted with about twenty times their volume of an aqueous 

 solution of one per cent chromic acid or five per cent potassium 

 bichromate. This solution will deodorize the feces and make them 

 much easier to handle. The mixture is thoroughly emulsified by 

 stirring, shaking, or agitating with a mechanical mixer. It is then 

 poured through a filter made of four thicknesses of cheesecloth. 

 The residuum should be stirred and washed with a small quantity 

 of water and the washings added to the filtrate. The filtrate, which 

 will contain most of the oocysts, is dispensed into graduated looo 

 milliliter separatory funnels and is allowed to sediment. After 



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