“…In 1983, an accidental laboratory infection demonstrated that a human isolate of C. parvum could be transmitted from one person to another (33). Since that time, outbreaks of cryptosporidiosis among children in day-care centers have been reported (2,3,56,62,93,131,172,217,237,254,292,301), hospital-acquired infections have been investigated (28,167,203,204), a number of waterborne outbreaks have been documented (86,107,129,271,290,291), and this protozoan is now recog-CLIN. MICROBIOL.…”