Degree Type

Thesis

Date of Award

2012

Degree Name

Master of Science

Department

Veterinary Diagnostic and Production Animal Medicine

First Advisor

Jeffrey J. Zimmerman

Second Advisor

Derald J. Holtkamp

Abstract

Surveillance for swine pathogens and health related biomarkers is of great importance to the financial success of the swine industry and the health of animal and human populations worldwide. Research has shown that the use of oral fluid specimens in diagnostics and surveillance provides many advantages over serum. To discover the full potential of this technology many aspects of its use must be evaluated e.g. sample collection and handling techniques, assay performance parameters and detection limits of pen-based samples.

As reviewed in Chapter 1, the detection of many analytes in human and animal oral fluid samples has been reported. In the process of these discoveries, it was been identified that oral fluid sample collection material, post-collection processing and sample storage can affect testing results of human and animal oral fluid samples. Though little data was found in the literature regarding these effects on animal samples, limited reports suggest they may similarly affect veterinary testing of oral fluid specimens. As more diagnostic tests for human and animal oral fluid samples become available, it will be important to consider if and how these external factors affect testing results.

Pursuant to the concerns identified in Chapter 1, the objective of the first research project (Chapter 2) was to evaluate the effect of oral fluid sampling material and post-collection processing on the results produced by antibody- and polymerase chain reaction-based assays. Oral fluid samples were collected from 104 pens of commercial wean-to-finish pigs using 3 types of rope. Processed (centrifuged and filtered) and unprocessed oral fluid samples were tested using commercial ELISAs for porcine reproductive and respiratory syndrome virus (PRRSV) antibodies and total IgM, IgA, and IgG. Only unprocessed samples were tested for PRRSV nucleic acid and processed samples for PRRSV neutralizing antibodies. It was found that all three factors could affect results, but statistically significant effects were non-uniform and assay-dependent.

The objective of the second study (Chapter 3) was to evaluate the detection limits of assays detecting PRRSV antibodies and PRRS virus in pen-based oral fluid samples from commercial swine. Five successive oral fluid samples were collected from 25 pens of commercial swine of known PRRSV prevalence (0%, 4%, 12%, 20% and 36%) with five pens per prevalence level. PRRSV prevalence was established by vaccinating commercial swine with an intramuscular modified live PRRSV vaccine 14 days prior to the trial. The vaccinated pigs were then introduced at the designated prevalence levels into pens of otherwise PRRSV negative pigs one day prior to sample collection. Serum was collected from each pig in each pen to confirm expected PRRSV prevalence. Oral fluid and vaccinated pig serum was tested using RT-PCR and ELISA by six laboratories. Intra-laboratory agreement was measured and predicted probability of PRRSV detection in pen-based oral fluid samples was estimated for each assay.

DOI

https://doi.org/10.31274/etd-180810-2052

Copyright Owner

Chris W. Olsen

Language

en

File Format

application/pdf

File Size

76 pages

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