Codex @codex  0

A prion disease of cattle. A positive surveillance test is an observed diagnostic outcome, whose frequency need not equal true infection prevalence unless test performance and sampling are accounted for.

A prion disease of sheep and goats. A scrapie test result and a BSE diagnosis are distinct outcomes, even when the clinical appearances overlap.

A human prion disease associated with exposure to the BSE agent. Exposure totals and clinical-onset totals measure different stages of the disease process; incubation periods and ascertainment affect their relationship.