title: Risk of infection with Cryptosporidium parvum and Cryptosporidium hominis in dairy cattle in the New York City watershed.
abstract: OBJECTIVE
  To determine the risk posed by Cryptosporidium parvum and Cryptosporidium hominis from dairy cattle in the New York City watershed (NYCW).
  
  
  METHODS
  Samples from cattle at risk for shedding Cryptosporidium organisms on randomly selected dairy farms in the NYCW.
  
  
  METHODS
  Feces were collected for 4 years from calves at risk for infection on 37 dairies. Oocysts were detected by use of centrifugation concentration-flotation microscopy. The DNA was directly isolated from fecal samples and used to amplify fragments of the small subunit ribosomal RNA and thrombospondin-related adhesion protein C-2 genes by use of nested polymerase chain reaction assays. Small subunit ribosomal RNA fragments were restriction digested by the enzyme Vspl and thrombospondin-related adhesion protein C-2 fragments were digested by Eco91l to distinguish between C hominis (formerly known as genotype 1) and C parvum (formerly known as genotype 2).
  
  
  RESULTS
  Of 437 fecal samples examined, 214 contained oocysts. Amplicons were generated for 200 samples. We can be certain, with 95% confidence, that cattle in the NYCW did not harbor C hominis.
  
  
  CONCLUSIONS
  Cryptosporidium infections in cattle are under examination because of the potential contamination of public waters by manure. Although cattle may be the source of zoonotic infection via C parvum, they pose little risk for C hominis (the strain commonly isolated from humans in waterborne outbreaks of disease). Other sources of oocysts should be considered when investigating outbreaks attributable to contaminated urban drinking water because cattle pose only a small risk via shedding of C hominis.
authors.affiliation: Animal Health Diagnostic Laboratory and Section of Epidemiology, Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Daryl V
authors.initials: DV
authors.lastname: Nydam
authors.forename: Gabbriella
authors.initials: G
authors.lastname: Lindergard
authors.forename: Fiametta
authors.initials: F
authors.lastname: Santucci
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Schaaf
authors.forename: Susan E
authors.initials: SE
authors.lastname: Wade
authors.forename: Hussni O
authors.initials: HO
authors.lastname: Mohammed
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000469:parasitology*; D003457:Cryptosporidiosis / Q000453:epidemiology / Q000662:veterinary*; D003458:Cryptosporidium / Q000235:genetics*; D017931:DNA Primers; D003612:Dairying; D005243:Feces / Q000469:parasitology; D005260:Female; D009518:New York / Q000453:epidemiology; D033661:Oocysts / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012150:Polymorphism, Restriction Fragment Length; D015800:Protozoan Proteins / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics; D018570:Risk Assessment; D013045:Species Specificity; D014881:Water Supply
chemical_list: D017931:DNA Primers; D015800:Protozoan Proteins; D012335:RNA, Ribosomal; C069428:thrombospondin-related adhesive protein, protozoan