Comparison of methods for estimation of individual-level prevalence based on pooled samples

We review frequentist and Bayesian approaches for estimating animal-level d isease prevalence using pooled samples obtained by simple random sampling. We determine the preferred approach for different prevalence scenarios and with varying knowledge about sensitivity and specificity values. When sensi tivity and specificity are perfect or known, we can choose between the larg e-sample theory estimates and the one-to-one relationship exact estimates. When sensitivity and specificity are unknown, we must use large-sample theo ry estimates or Bayesian methodology (which gives exact estimates). However , when the large-sample theory produces a negative lower confidence limit, we must use one of the exact methods. We compare estimates from each approa ch using culture results from pools of 20 eggs from three flocks on a Calif ornia ranch that were producing eggs that were contaminated with Salmonella enteritidis phage type 4. (C) 1999 Elsevier Science B.V. All rights reserv ed.