title: Analyzing BSE surveillance in low prevalence countries.
abstract: If the prevalence of bovine spongiform encephalopathy (BSE) varies among cohorts within a population, stratified analysis of BSE surveillance data may allow identification of differences in BSE exposure that are important with respect to the design and evaluation of disease prevention and control measures. In low BSE prevalence populations, however, surveillance at levels that meet or exceed international guidelines may provide insufficient statistical power to distinguish prevalence levels among cohorts. Furthermore, overstratification to account for hypothetical variability in the population may inflate uncertainty in BSE risk estimates.
authors.affiliation: Office of Risk Assessment and Cost Benefit Analysis, U.S. Department of Agriculture, 1400 Independence Avenue SW, Washington, DC 20250, USA. mpowell@uce.usda.gov
authors.forename: Mark
authors.initials: M
authors.lastname: Powell
authors.forename: Aaron
authors.initials: A
authors.lastname: Scott
authors.forename: Eric
authors.initials: E
authors.lastname: Ebel
mesh_terms: D000818:Animals; D002417:Cattle; D015331:Cohort Studies; D016643:Encephalopathy, Bovine Spongiform / Q000453:epidemiology*; D008403:Mass Screening; D015995:Prevalence; D018570:Risk Assessment; D018571:Sentinel Surveillance / Q000662:veterinary; D013997:Time Factors