title: Daily shedding dynamics of E. coli O157 in an Australian grass-fed beef herd.
abstract: This study aimed to describe the diurnal shedding dynamics of Escherichia coli O157 in cattle managed on pasture. The purpose was to identify the value of a single measurement for predicting the shedding status on subsequent days. Over a 14-day period, 24 beef cows with known E. coli O157 shedding status were sampled twice daily or daily (21 sampling points) and E. coli O157 was enumerated from faeces. No association between shedding status of individual animals within a 7-h period was identified (odds ratio 1·5, P = 0·08). Short-interval sampling demonstrated substantial diurnal volatility in shedding of E. coli O157 that is not evident in studies based on long-interval (>7 days) sampling. The findings contribute to and support previous findings on the question why it has been difficult to achieve progress in understanding the epidemiology of E. coli O157 infection in cattle.
authors.affiliation: School of Animal and Veterinary Science,Charles Sturt University,Australia.
authors.forename: G A C
authors.initials: GA
authors.lastname: Lammers
authors.affiliation: New South Wales Department of Primary Industries,Wollongbar Primary Industries Institute,Australia.
authors.forename: D
authors.initials: D
authors.lastname: Jordan
authors.affiliation: Department of Clinical Sciences,Colorado State University,CO,USA.
authors.forename: C S
authors.initials: CS
authors.lastname: McCONNEL
authors.affiliation: School of Animal and Veterinary Science,Charles Sturt University,Australia.
authors.forename: J
authors.initials: J
authors.lastname: Heller
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D057138:Bacterial Shedding; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000382:microbiology; D015169:Colony Count, Microbial / Q000662:veterinary; D004032:Diet / Q000662:veterinary; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000502:physiology*; D005243:Feces / Q000382:microbiology; D005260:Female; D009517:New South Wales / Q000453:epidemiology
keywords: 
                 Escherichia coli
              ; daily shedding; veterinary epidemiology; zoonotic foodborne diseases