title: Sheep may not be an important zoonotic reservoir for Cryptosporidium and Giardia parasites.
abstract: Little is known of the prevalence of Cryptosporidium and Giardia parasites in sheep and the genotypes that they harbor, although potentially sheep may contribute significantly to contamination of watersheds. In the present study, conducted in Western Australia, a total of 1,647 sheep fecal samples were screened for the presence of Cryptosporidium and Giardia spp. using microscopy, and a subset (n = 500) were screened by PCR and genotyped. Analysis revealed that although both parasites were detected in a high proportion of samples by PCR (44% and 26% for Giardia and Cryptosporidium spp., respectively), with the exception of one Cryptosporidium hominis isolate, the majority of isolates genotyped are not commonly found in humans. These results suggest that the public health risk of sheep-derived Cryptosporidium and Giardia spp. in catchment areas and effluent may be overestimated and warrant further investigation.
authors.affiliation: Division of Health Sciences, School of Veterinary and Biomedical Science, Murdoch University, Murdoch, Western Australia, Australia 6150. Una.Ryan@murdoch.edu.au
authors.forename: Una M
authors.initials: UM
authors.lastname: Ryan
authors.forename: Caroline
authors.initials: C
authors.lastname: Bath
authors.forename: Ian
authors.initials: I
authors.lastname: Robertson
authors.forename: Carolyn
authors.initials: C
authors.lastname: Read
authors.forename: Aileen
authors.initials: A
authors.lastname: Elliot
authors.forename: Linda
authors.initials: L
authors.lastname: McInnes
authors.forename: Rebecca
authors.initials: R
authors.lastname: Traub
authors.forename: Brown
authors.initials: B
authors.lastname: Besier
mesh_terms: D000818:Animals; D003457:Cryptosporidiosis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary; D003458:Cryptosporidium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D003967:Diarrhea / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary; D004197:Disease Reservoirs; D005243:Feces / Q000469:parasitology; D005838:Genotype; D005872:Giardia / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D005873:Giardiasis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D015995:Prevalence; D017422:Sequence Analysis, DNA; D012757:Sheep Diseases / Q000453:epidemiology* / Q000469:parasitology* / Q000635:transmission; D034561:Sheep, Domestic / Q000469:parasitology; D015047:Zoonoses