title: A longitudinal study of Escherichia coli O157 in fourteen cattle herds.
abstract: Escherichia coli O157 shedding in 14 cattle herds was determined by faecal culture at intervals of approximately 1 month for up to 13 months. The overall prevalence was 1.0% (113/10832 faecal samples) and 9 of the 14 herds were detected as positive. Herds positive 2 years previously (n = 5) had a higher prevalence of positive cattle (median = 1.9%) than herds which had been negative on a previous sampling (n = 8, median = 0.2%). Weaned heifers had a higher prevalence (1.8%) than did unweaned calves (0.9%) or adults (0.4%). For all herds the highest prevalence occurred in the summer months, which resulted in most of the positive faecal samples being collected on a minority of sampling visits.
authors.affiliation: Field Disease Investigation Unit, Washington State University, Pullman 99164-6610, USA.
authors.forename: D D
authors.initials: DD
authors.lastname: Hancock
authors.forename: T E
authors.initials: TE
authors.lastname: Besser
authors.forename: D H
authors.initials: DH
authors.lastname: Rice
authors.forename: D E
authors.initials: DE
authors.lastname: Herriott
authors.forename: P I
authors.initials: PI
authors.lastname: Tarr
mesh_terms: D000367:Age Factors; D000822:Animal Husbandry; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157; D005243:Feces / Q000382:microbiology; D008137:Longitudinal Studies; D015995:Prevalence; D012621:Seasons; D013997:Time Factors