Detection of total and PRRSV-specific antibodies in oral fluids collected with different rope types from PRRSV-vaccinated and experimentally infected pigs.

Inge Decorte,Ann Cay,Hans J Nauwynck,Wander Van Breedam,Nick De Regge,Yves Van Der Stede

doi:10.1186/1746-6148-10-134

Inge Decorte, Ann Cay + Show 4 more

Open Access

https://doi.org/10.1186/1746-6148-10-134

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Abstract

BackgroundOral fluid collected by means of ropes has the potential to replace serum for monitoring and surveillance of important swine pathogens. Until now, the most commonly used method to collect oral fluid is by hanging a cotton rope in a pen. However, concerns about the influence of rope material on subsequent immunological assays have been raised. In this study, we evaluated six different rope materials for the collection of oral fluid and the subsequent detection of total and PRRSV-specific antibodies of different isotypes in oral fluid collected from PRRSV-vaccinated and infected pigs.ResultsAn initial experiment showed that IgA is the predominant antibody isotype in porcine saliva. Moreover, it was found that synthetic ropes may yield higher amounts of IgA, whereas all rope types seemed to be equally suitable for IgG collection. Although IgA is the predominant antibody isotype in porcine oral fluid, the PRRSV-specific IgA-based IPMA and ELISA tests were clearly not ideal for sensitive detection of PRRSV-specific IgA antibodies. In contrast, PRRSV-specific IgG in oral fluids was readily detected in PRRSV-specific IgG-based IPMA and ELISA tests, indicating that IgG is a more reliable isotype for monitoring PRRSV-specific antibody immunity in vaccinated/infected animals via oral fluids with the currently available tests.ConclusionsSince PRRSV-specific IgG detection seems more reliable than PRRSV-specific IgA detection for monitoring PRRSV-specific antibody immunity via oral fluids, and since all rope types yield equal amounts of IgG, it seems that the currently used cotton ropes are an appropriate choice for sample collection in PRRSV monitoring.

Highlights

Oral fluid collected by means of ropes has the potential to replace serum for monitoring and surveillance of important swine pathogens
Influence of rope material on oral fluid collection During the acclimatization period, animals were stimulated to chew on six different rope materials by positive reinforcement
We evaluated if immunoperoxidase monolayer assay (IPMA) and enzyme-linked immunosorbent assays (ELISA) assays can be used for the sensitive detection of porcine reproductive and respiratory syndrome virus (PRRSV)-specific IgA/ IgG antibodies in oral fluid samples of PRRSV-vaccinated or infected animals

Summary

Introduction

Oral fluid collected by means of ropes has the potential to replace serum for monitoring and surveillance of important swine pathogens. We evaluated six different rope materials for the collection of oral fluid and the subsequent detection of total and PRRSV-specific antibodies of different isotypes in oral fluid collected from PRRSV-vaccinated and infected pigs. Detection of specific IgA, IgG and IgM in saliva has already been evaluated to monitor the levels of virus-specific antibody immunity. Over the last few years, several studies have evaluated the use of oral fluids as samples for use in antibody-based veterinary diagnostics. Relatively little information is available on the amounts of virusspecific IgA, IgG and IgM antibodies present in oral fluids of virus-infected pigs. Oral fluid specimens collected from pigs with cotton or hemp contained higher amounts of PRRSV-specific IgG compared to samples collected with nylon rope [18]

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