ABSTRACT
Cryptosporidiosis has typically been considered a disease of animals, and the occasional human case has been considered a rare zoonosis or evidence of immunoincompetence. In this report, person-to-person transmission is postulated for illness documented in two of five rooms of a day-care center. Of 46 persons (34 children and 12 staff members), 29 (63%) became ill, and 27 (58.7%) had Cryptosporidium in their stools. Symptoms in children included diarrhea (55%), weight loss (25%), flatulence (15%), and fever (10%). Symptoms of cryptosporidiosis ceased without treatment, and three months later all previously infested children had negative stool specimens. Questionnaires administered to parents revealed no association with water, travel, or ill pets. Cultures for Salmonella, Shigella, and Campylobacter were negative; no viral cultures were done. All affected children and their parents were immunocompetent. It is presumed that this outbreak occurred as a result of person-to-person transmission of the protozoa in the day-care centers, primarily by staff with inadequate hygiene practices. Physicians should look for this organism in children or adults who present with diarrhea and gastroenteritis in which the pathogenic agent is not readily identifiable by the usual bacterial cultures.