HOST-PARASITE RELATIONS: INTESTINAL PROTOZOA 



after diarrhea commenced, giving" a prepatent period 

 of 28 days. The patent period continued for 13 days, 

 i.e., during the second diarrheic period and 4 days after 

 the feces became formed. No oocysts were observed in 

 the feces during the succeeding 6 months and no further 

 diarrhea appeared. Evidently no relapse has been suf- 

 fered by the patient since an account of it has not been 

 reported. 



Other human infections. Pons (1925a) has described 

 two cases of coccidiosis in man that are interesting al- 

 though not as simple as that of Connal. The first pa- 

 tient suffered with a choleric syndrome for 6 days; he 

 subsequently appeared normal for 10 days; diarrhea, 

 with stools containing blood and mucus, then commenced 

 and continued for 9 days; a normal period of 20 days 

 ensued ; diarrhea again appeared, lasting 6 days. Giardias 

 were noted but no dysentery bacilli or other pathogenic 

 organisms. Oocysts appeared 3 days before the end of 

 the last diarrheic period and did not definitely disappear 

 until 30 days later. The second case reported by Pons 

 was that of a woman who had suffered from attacks of 

 diarrhea for 10 months before coccidia were discovered 

 in her feces. Oocysts were passed for 16 days and then 

 no more could be found. 



These two cases resemble that of Connal and infections 

 in cats and dogs in several respects: (i) diarrhea pre- 

 ceded the appearance of the oocysts ; that is, the incuba- 

 tion period was shorter than the prepatent period; (2) 

 the oocysts appeared for several weeks and then were 

 apparently entirely eliminated, the patent period being 

 13 days in Connal's case, 30 and 16 days respectively in 

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