Campus Units

Statistics, Veterinary Diagnostic and Production Animal Medicine

Document Type

Article

Publication Version

Published Version

Publication Date

9-2017

Journal or Book Title

Veterinary Microbiology

Volume

209

First Page

20

Last Page

29

DOI

10.1016/j.vetmic.2017.02.004

Abstract

Formulas and software for calculating sample size for surveys based on individual animal samples are readily available. However, sample size formulas are not available for oral fluids and other aggregate samples that are increasingly used in production settings. Therefore, the objective of this study was to develop sampling guidelines for oral fluid-based porcine reproductive and respiratory syndrome virus (PRRSV) surveys in commercial swine farms. Oral fluid samples were collected in 9 weekly samplings from all pens in 3 barns on one production site beginning shortly after placement of weaned pigs. Samples (n = 972) were tested by real-time reverse-transcription PCR (RT-rtPCR) and the binary results analyzed using a piecewise exponential survival model for interval-censored, time-to-event data with misclassification. Thereafter, simulation studies were used to study the barn-level probability of PRRSV detection as a function of sample size, sample allocation (simple random sampling vs fixed spatial sampling), assay diagnostic sensitivity and specificity, and pen-level prevalence. These studies provided estimates of the probability of detection by sample size and within-barn prevalence. Detection using fixed spatial sampling was as good as, or better than, simple random sampling. Sampling multiple barns on a site increased the probability of detection with the number of barns sampled. These results are relevant to PRRSV control or elimination projects at the herd, regional, or national levels, but the results are also broadly applicable to contagious pathogens of swine for which oral fluid tests of equivalent performance are available.

Comments

This article is published as Rotolo, Marisa L., Yaxuan Sun, Chong Wang, Luis Giménez-Lirola, David H. Baum, Phillip C. Gauger, Karen M. Harmon, Marlin Hoogland, Rodger Main, and Jeffrey J. Zimmerman. "Sampling guidelines for oral fluid-based surveys of group-housed animals." Veterinary microbiology 209 (2017): 20-29. doi: 10.1016/j.vetmic.2017.02.004.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

The Authors

Language

en

File Format

application/pdf

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