title: Genetic diversity within Cryptosporidium parvum and related Cryptosporidium species.
abstract: To assess the genetic diversity in Cryptosporidium parvum, we have sequenced the small subunit (SSU) rRNA gene of seven Cryptosporidium spp., various isolates of C. parvum from eight hosts, and a Cryptosporidium isolate from a desert monitor. Phylogenetic analysis of the SSU rRNA sequences confirmed the multispecies nature of the genus Cryptosporidium, with at least four distinct species (C. parvum, C. baileyi, C. muris, and C. serpentis). Other species previously defined by biologic characteristics, including C. wrairi, C. meleagridis, and C. felis, and the desert monitor isolate, clustered together or within C. parvum. Extensive genetic diversities were present among C. parvum isolates from humans, calves, pigs, dogs, mice, ferrets, marsupials, and a monkey. In general, specific genotypes were associated with specific host species. A PCR-restriction fragment length polymorphism technique previously developed by us could differentiate most Cryptosporidium spp. and C. parvum genotypes, but sequence analysis of the PCR product was needed to differentiate C. wrairi and C. meleagridis from some of the C. parvum genotypes. These results indicate a need for revision in the taxonomy and assessment of the zoonotic potential of some animal C. parvum isolates.
authors.affiliation: Division of Parasitic Diseases, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services, Atlanta, Georgia 30341, USA. lax0@cdc.gov
authors.forename: L
authors.initials: L
authors.lastname: Xiao
authors.forename: U M
authors.initials: UM
authors.lastname: Morgan
authors.forename: J
authors.initials: J
authors.lastname: Limor
authors.forename: A
authors.initials: A
authors.lastname: Escalante
authors.forename: M
authors.initials: M
authors.lastname: Arrowood
authors.forename: W
authors.initials: W
authors.lastname: Shulaw
authors.forename: R C
authors.initials: RC
authors.lastname: Thompson
authors.forename: R
authors.initials: R
authors.lastname: Fayer
authors.forename: A A
authors.initials: AA
authors.lastname: Lal
mesh_terms: D000818:Animals; D001483:Base Sequence; D003458:Cryptosporidium / Q000235:genetics* / Q000302:isolation & purification; D016785:Cryptosporidium parvum / Q000235:genetics* / Q000302:isolation & purification; D017931:DNA Primers / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D004285:Dogs; D017125:Genes, Protozoan; D014644:Genetic Variation; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D012689:Sequence Homology, Nucleic Acid
chemical_list: D017931:DNA Primers; D016054:DNA, Protozoan; D004275:DNA, Ribosomal