Evaluation of real‐time polymerase chain reaction for the diagnosis of protozoal myeloencephalitis in horses using cerebrospinal fluid

Abstract Background Equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona remains an antemortem diagnostic challenge in some horses. Recent work suggested the use of real‐time PCR (rtPCR) on cerebrospinal fluid (CSF) as a promising diagnostic tool. Objective To evaluate the sensitiv...

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Main Authors: Carla Katherine Enriquez, Jennifer K. Morrow, Amy Graves, Amy Johnson
Format: Article
Language:English
Published: Wiley 2023-09-01
Series:Journal of Veterinary Internal Medicine
Subjects:
Online Access:https://doi.org/10.1111/jvim.16826
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author Carla Katherine Enriquez
Jennifer K. Morrow
Amy Graves
Amy Johnson
author_facet Carla Katherine Enriquez
Jennifer K. Morrow
Amy Graves
Amy Johnson
author_sort Carla Katherine Enriquez
collection DOAJ
description Abstract Background Equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona remains an antemortem diagnostic challenge in some horses. Recent work suggested the use of real‐time PCR (rtPCR) on cerebrospinal fluid (CSF) as a promising diagnostic tool. Objective To evaluate the sensitivity and specificity of S. neurona rtPCR on CSF for EPM diagnosis using horses with EPM and S. neurona‐seropositive horses with other neurologic conditions. Animals Ninety‐nine horses with neurologic disease that underwent complete neurologic examination, CSF collection, and, if euthanized, necropsy including the central nervous system (CNS). Methods Retrospective case‐control study using banked CSF samples. Samples from horses with neurologic abnormalities and necropsy‐confirmed EPM diagnosis, presumptive EPM diagnosis using strict criteria (SnSAG2/4/3 ELISA serum:CSF titer ratios <50) and horses diagnosed with other neurologic diseases were used. Results Fifty‐two horses had EPM; 23 were confirmed on necropsy, and 29 were presumptive clinical diagnoses. The other 47 horses all had necropsy‐confirmed diagnoses. Four of the 47 horses had normal neurologic findings on necropsy and the remaining 43 horses had neurologic diseases including equine degenerative myeloencephalopathy (EDM), cervical vertebral stenotic myelopathy, trauma, and other miscellaneous conditions. One CSF sample was weakly positive for S. neurona by rtPCR, this sample was obtained from a horse with confirmed EDM. Samples from the other 98 horses were negative for S. neurona by rtPCR. Conclusions and Clinical Importance Our study contradicts previous conclusions that S. neurona rtPCR is potentially useful for EPM diagnosis, because our results indicate that the assay has a low sensitivity (0%) for EPM.
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spelling doaj.art-cbb709fa318b4f11b965f525c02feb922023-09-01T14:18:40ZengWileyJournal of Veterinary Internal Medicine0891-66401939-16762023-09-013751893189810.1111/jvim.16826Evaluation of real‐time polymerase chain reaction for the diagnosis of protozoal myeloencephalitis in horses using cerebrospinal fluidCarla Katherine Enriquez0Jennifer K. Morrow1Amy Graves2Amy Johnson3Department of Clinical Studies University of Pennsylvania New Bolton Center Hospital for Large Animals Kennett Square Pennsylvania USAEquine Diagnostic Solutions, LLC Lexington Kentucky USAEquine Diagnostic Solutions, LLC Lexington Kentucky USADepartment of Clinical Studies University of Pennsylvania New Bolton Center Hospital for Large Animals Kennett Square Pennsylvania USAAbstract Background Equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona remains an antemortem diagnostic challenge in some horses. Recent work suggested the use of real‐time PCR (rtPCR) on cerebrospinal fluid (CSF) as a promising diagnostic tool. Objective To evaluate the sensitivity and specificity of S. neurona rtPCR on CSF for EPM diagnosis using horses with EPM and S. neurona‐seropositive horses with other neurologic conditions. Animals Ninety‐nine horses with neurologic disease that underwent complete neurologic examination, CSF collection, and, if euthanized, necropsy including the central nervous system (CNS). Methods Retrospective case‐control study using banked CSF samples. Samples from horses with neurologic abnormalities and necropsy‐confirmed EPM diagnosis, presumptive EPM diagnosis using strict criteria (SnSAG2/4/3 ELISA serum:CSF titer ratios <50) and horses diagnosed with other neurologic diseases were used. Results Fifty‐two horses had EPM; 23 were confirmed on necropsy, and 29 were presumptive clinical diagnoses. The other 47 horses all had necropsy‐confirmed diagnoses. Four of the 47 horses had normal neurologic findings on necropsy and the remaining 43 horses had neurologic diseases including equine degenerative myeloencephalopathy (EDM), cervical vertebral stenotic myelopathy, trauma, and other miscellaneous conditions. One CSF sample was weakly positive for S. neurona by rtPCR, this sample was obtained from a horse with confirmed EDM. Samples from the other 98 horses were negative for S. neurona by rtPCR. Conclusions and Clinical Importance Our study contradicts previous conclusions that S. neurona rtPCR is potentially useful for EPM diagnosis, because our results indicate that the assay has a low sensitivity (0%) for EPM.https://doi.org/10.1111/jvim.16826CSF analysisequine protozoal myeloencephalopathyhorsemolecular biologyneurologyparasitology
spellingShingle Carla Katherine Enriquez
Jennifer K. Morrow
Amy Graves
Amy Johnson
Evaluation of real‐time polymerase chain reaction for the diagnosis of protozoal myeloencephalitis in horses using cerebrospinal fluid
Journal of Veterinary Internal Medicine
CSF analysis
equine protozoal myeloencephalopathy
horse
molecular biology
neurology
parasitology
title Evaluation of real‐time polymerase chain reaction for the diagnosis of protozoal myeloencephalitis in horses using cerebrospinal fluid
title_full Evaluation of real‐time polymerase chain reaction for the diagnosis of protozoal myeloencephalitis in horses using cerebrospinal fluid
title_fullStr Evaluation of real‐time polymerase chain reaction for the diagnosis of protozoal myeloencephalitis in horses using cerebrospinal fluid
title_full_unstemmed Evaluation of real‐time polymerase chain reaction for the diagnosis of protozoal myeloencephalitis in horses using cerebrospinal fluid
title_short Evaluation of real‐time polymerase chain reaction for the diagnosis of protozoal myeloencephalitis in horses using cerebrospinal fluid
title_sort evaluation of real time polymerase chain reaction for the diagnosis of protozoal myeloencephalitis in horses using cerebrospinal fluid
topic CSF analysis
equine protozoal myeloencephalopathy
horse
molecular biology
neurology
parasitology
url https://doi.org/10.1111/jvim.16826
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AT amygraves evaluationofrealtimepolymerasechainreactionforthediagnosisofprotozoalmyeloencephalitisinhorsesusingcerebrospinalfluid
AT amyjohnson evaluationofrealtimepolymerasechainreactionforthediagnosisofprotozoalmyeloencephalitisinhorsesusingcerebrospinalfluid