title: Molecular and phylogenetic approaches for assessing sources of Cryptosporidium contamination in water.
abstract: The high sequence diversity and heterogeneity observed within species or genotypes of Cryptosporidium requires phylogenetic approaches for the identification of novel sequences obtained from the environment. A long-term study on Cryptosporidium in the agriculturally-intensive South Nation River watershed in Ontario, Canada was undertaken, in which 60 sequence types were detected. Of these sequence types 33 were considered novel with no identical matches in GenBank. Detailed phylogenetic analysis identified that most sequences belonged to 17 previously described species: Cryptosporidium andersoni, Cryptosporidium baileyi, Cryptosporidium hominis, Cryptosporidium parvum, Cryptosporidium ubiquitum, Cryptosporidium meleagridis, muskrat I, muskrat II, deer mouse II, fox, vole, skunk, shrew, W12, W18, W19 and W25 genotypes. In addition, two new genotypes were identified, W27 and W28. C. andersoni and the muskrat II genotype were most frequently detected in the water samples. Species associated with livestock made up 39% of the total molecular detections, while wildlife associated species and genotypes accounted for 55% of the Cryptosporidium identified. The human pathogenic species C. hominis and C. parvum had an overall prevalence of 1.6% in the environment, indicating a small risk to humans from the Cryptosporidium present in the watershed. Phylogenetic analysis and knowledge of host-parasite relationships are fundamental in using Cryptosporidium as a source-tracking or human health risk assessment tool.
authors: Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.
authors: Norma J
authors: NJ
authors: Ruecker
authors: Joanne C
authors: JC
authors: Matsune
authors: Graham
authors: G
authors: Wilkes
authors: David R
authors: DR
authors: Lapen
authors: Edward
authors: E
authors: Topp
authors: Thomas A
authors: TA
authors: Edge
authors: Christoph W
authors: CW
authors: Sensen
authors: Lihua
authors: L
authors: Xiao
authors: Norman F
authors: NF
authors: Neumann
mesh_terms: D000383:Agriculture / Q000706:statistics & numerical data; D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D019295:Computational Biology; D003458:Cryptosporidium / Q000235:genetics*; D014644:Genetic Variation; D054884:Host-Pathogen Interactions; D006801:Humans; D058751:Livestock / Q000469:parasitology*; D054892:Metagenome / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009864:Ontario; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D018570:Risk Assessment; D045483:Rivers / Q000469:parasitology*; D017422:Sequence Analysis, DNA
chemical_list: D012337:RNA, Ribosomal, 18S