Sir.—Cryptosporidium species have recently been recognized as a cause of gastrointestinal disease in immunocompetent healthy young children in day-care centers,1,2 in family outbreaks,3 and in developing countries, where they account for 3.6% to 7.6% of cases of acute diarrhea in preschool children.4
Patient Reports.—Over the last six months, three of 36 unrelated children between the ages of 11 months and 8 years who Were examined because of chronic diarrhea (longer than two weeks' duration) were found to be infected with Cryptosporidium. Their ages were 14 months, 17 months, and 7 years, respectively, and their symptoms consisted of watery to loose large-volume stools passed three to six times per day, accompanied by mild abdominal cramps. There was no history of fever, vomiting, or blood in the stools. None of these patients had been recently taking antibiotics, and results of multiple examinations of their stools for bacterial