Volume 92, Issue 1
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



Although and cause the majority of human cryptosporidiosis cases, other species are also capable of infecting humans, particularly when individuals are immunocompromised. Ten cases have been reported, primarily in human immunodeficiency virus (HIV) -positive patients with diarrhea. However, asymptomatic cases were reported in two HIV-negative children, and in another case, age and immune status were not described. This study examines the infectivity of in six healthy adults. Volunteers were challenged with 10 oocysts and monitored for 6 weeks for infection and/or illness. All six patients became infected. Two patients experienced a self-limited diarrheal illness. Total oocysts shed during the study ranged from 6.7 × 10 to 4.1 × 10, and the number was slightly higher in volunteers with diarrhea (2.8 × 10) than asymptomatic shedders (4.4 × 10). -infected subjects shed oocysts longer than occurred with other species studied in healthy volunteers. Three volunteers shed oocysts for 7 months. Physical examinations were normal, with no reported recurrence of diarrhea or other gastrointestinal complaints. Two persistent shedders were treated with nitazoxanide, and the infection was resolved. Thus, healthy adults are susceptible to , which can cause mild diarrhea and result in persistent, asymptomatic infection.


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  • Received : 21 Aug 2014
  • Accepted : 04 Sep 2014

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