title: Cryptosporidium dose response studies: variation between isolates.
abstract: The infectivity of three different isolates of the waterborne protozoan parasite Cryptosporidium parvum has been tested in human feeding studies. These three isolates (Iowa, TAMU, and UCP) have different ID50s, indicating substantial variation in their infectivity for humans. This finding is of great importance for quantitative risk assessment as it provides strong evidence for heterogeneity in infectivity among isolates of the same species.
authors.affiliation: National Institute for Public Health and the Environment, Bilthoven, The Netherlands. Peter.Teunis@rivm.nl
authors.forename: Peter F M
authors.initials: PF
authors.lastname: Teunis
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Chappell
authors.forename: Pablo C
authors.initials: PC
authors.lastname: Okhuysen
mesh_terms: D000818:Animals; D003457:Cryptosporidiosis / Q000209:etiology / Q000469:parasitology; D003458:Cryptosporidium / Q000302:isolation & purification* / Q000472:pathogenicity*; D006801:Humans; D008954:Models, Biological; D033661:Oocysts / Q000302:isolation & purification; D018570:Risk Assessment; D014774:Virulence