title: Infectivity of a Cryptosporidium parvum isolate of cervine origin for healthy adults and interferon-gamma knockout mice.
abstract: The infectivity of a Cryptosporidium parvum isolate of cervine origin (type 2, Moredun) propagated in calves was investigated simultaneously in healthy adult human volunteers and in interferon-gamma knockout (GKO) mice. After exposure to 100-3000 oocysts, 16 volunteers recorded, for a duration of 6 weeks, the number and form of stools that they passed and any symptoms that they experienced. Oocyst excretion was assessed by enzyme-linked immunosorbent assay and direct immunofluorescence assay. Eleven subjects (69%) became ill, and 8 subjects (50%) shed oocysts in stool. The median duration of illness was 169 h, and the median number of unformed stools passed was 24. The duration and intensity of symptoms were more severe than were those associated with previously studied isolates. The median infectious dose was estimated to be 300 oocysts for humans and 1 oocyst for the GKO mouse model. The Moredun isolate was more pathogenic than the reference GCH-1 isolate. The GKO mouse model of cryptosporidiosis is useful for discerning isolate-specific differences in pathogenicity.
authors: Department of Medicine, Division of Infectious Diseases, and School of Public Health, University of Texas-Houston Health Science Center, Houston, TX 77030, USA. Pablo.C.Okhuysen@uth.tmc.edu
authors: Pablo C
authors: PC
authors: Okhuysen
authors: Stephen M
authors: SM
authors: Rich
authors: Cynthia L
authors: CL
authors: Chappell
authors: Kevin A
authors: KA
authors: Grimes
authors: Giovanni
authors: G
authors: Widmer
authors: Xiaochuan
authors: X
authors: Feng
authors: Saul
authors: S
authors: Tzipori
mesh_terms: D000328:Adult; D000818:Animals; D001835:Body Weight; D003457:Cryptosporidiosis / Q000209:etiology*; D016785:Cryptosporidium parvum / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D003670:Deer / Q000469:parasitology*; D003967:Diarrhea / Q000209:etiology; D004198:Disease Susceptibility; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout
chemical_list: D007371:Interferon-gamma