Prevalence-dependent use of serological tests for diagnosing glanders in horses

Lisa D Sprague,Reena Zachariah,Maria Joseph,Heinrich Neubauer,Ulrich Wernery,Renate Wernery,Holger C Scholz

doi:10.1186/1746-6148-5-32

Lisa D Sprague, Reena Zachariah + Show 5 more

Open Access

https://doi.org/10.1186/1746-6148-5-32

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Abstract

BackgroundThe internationally mandatory complement fixation test (CFT) for testing of equine sera for the absence of glanders has repeatedly led to discrepant results. Not only do "false positive" sera pose a problem for the diagnostician and the animal health authorities but they can also result in significant financial losses for the animal owners.Due to the very low prevalence of glanders in the horse population it is of major importance to use tests with a high specificity to overcome unreliable predictive values. We have compared formalin-fixed B. mallei whole cell antigen and a well characterised mouse monoclonal antibody with regard to their specificity and sensitivity for glanders serodiagnosis using CFT, an indirect (i) and a competitive (c) ELISA platform.ResultsOur results show that the CFT is still a very reliable technique in horse populations with very low glanders prevalence. The cELISA has a high sensitivity and specificity comparable to that of the CFT. The cELISA offers the possibility for automatisation, can be applied to non-complement fixing sera and used for various host species.ConclusionThe CFT is still the method of choice for testing horses for the absence of glanders.

Highlights

The internationally mandatory complement fixation test (CFT) for testing of equine sera for the absence of glanders has repeatedly led to discrepant results
This paper describes the use of a formalin-fixed B. mallei whole cell antigen, and the well characterised B. mallei specific monoclonal antibody 3D11 in an indirect and a competitive enzymelinked immunosorbent assay (ELISA) for the serodiagnosis of glanders in comparison to the CFT
In Group I, 100% specificity was observed for all samples tested with the CFT and both antigens

Summary

Introduction

The internationally mandatory complement fixation test (CFT) for testing of equine sera for the absence of glanders has repeatedly led to discrepant results. Due to the very low prevalence of glanders in the horse population it is of major importance to use tests with a high specificity to overcome unreliable predictive values. We have compared formalin-fixed B. mallei whole cell antigen and a well characterised mouse monoclonal antibody with regard to their specificity and sensitivity for glanders serodiagnosis using CFT, an indirect (i) and a competitive (c) ELISA platform. The etiologic agent of glanders is Burkholderia mallei, a Gram-negative, nonmotile, facultative intracellular bacterium. And latently (page number not for citation purposes) http://www.biomedcentral.com/1746-6148/5/32 infected carriers spread the bacterium under crowding conditions and stress, via infected food and drinking water or commonly used harnesses

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