title: Genetic characterization and transmission cycles of Cryptosporidium species isolated from humans in New Zealand.
abstract: Little is known about the genetic characteristics, distribution, and transmission cycles of Cryptosporidium species that cause human disease in New Zealand. To address these questions, 423 fecal specimens containing Cryptosporidium oocysts and obtained from different regions were examined by the PCR-restriction fragment length polymorphism technique. Indeterminant results were resolved by DNA sequence analysis. Two regions supplied the majority of isolates: one rural and one urban. Overall, Cryptosporidium hominis accounted for 47% of the isolates, with the remaining 53% being the C. parvum bovine genotype. A difference, however, was observed between the Cryptosporidium species from rural and urban isolates, with C. hominis dominant in the urban region, whereas the C. parvum bovine genotype was prevalent in rural New Zealand. A shift in transmission cycles was detected between seasons, with an anthroponotic cycle in autumn and a zoonotic cycle in spring. A novel Cryptosporidium sp., which on DNA sequence analysis showed a close relationship with C. canis, was detected in two unrelated children from different regions, illustrating the genetic diversity within this genus.
authors.affiliation: Protozoa Research Unit, Institute of Molecular BioSciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand. J.J.Learmonth@massey.ac.nz
authors.forename: James J
authors.initials: JJ
authors.lastname: Learmonth
authors.forename: George
authors.initials: G
authors.lastname: Ionas
authors.forename: Kim A
authors.initials: KA
authors.lastname: Ebbett
authors.forename: Errol S
authors.initials: ES
authors.lastname: Kwan
mesh_terms: D000818:Animals; D001483:Base Sequence; D003458:Cryptosporidium / Q000145:classification / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012621:Seasons
chemical_list: D012337:RNA, Ribosomal, 18S