Department of Clinical Studies, University of Pennsylvania New Bolton Center Hospital for Large Animals, Kennett Square, Pennsylvania, USA.
Equine Diagnostic Solutions, LLC, Lexington, Kentucky, USA.
J Vet Intern Med. 2023 Sep-Oct;37(5):1893-1898. doi: 10.1111/jvim.16826. Epub 2023 Aug 7.
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.
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.
Ninety-nine horses with neurologic disease that underwent complete neurologic examination, CSF collection, and, if euthanized, necropsy including the central nervous system (CNS).
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.
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.
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.
由 Sarcocystis neurona 引起的马脑原虫病（EPM）在某些马匹中仍然是一种生前诊断挑战。最近的研究表明，实时聚合酶链反应（rtPCR）检测脑脊液（CSF）可能是一种有前途的诊断工具。
使用患有 EPM 的马匹和患有其他神经疾病但 S. neurona 血清阳性的马匹，评估 S. neurona rtPCR 检测 CSF 对 EPM 诊断的敏感性和特异性。
99 匹患有神经疾病的马匹接受了全面的神经检查、CSF 采集，如果进行安乐死，则进行包括中枢神经系统（CNS）在内的尸检。
使用银行存储的 CSF 样本进行回顾性病例对照研究。使用来自神经异常马匹和神经病理学确诊 EPM 诊断、严格标准下推定 EPM 诊断（SnSAG2/4/3 ELISA 血清：CSF 滴度比<50）以及诊断为其他神经疾病的马匹的 CSF 样本。
52 匹马患有 EPM；23 例通过尸检确诊，29 例为推定临床诊断。其余 47 匹马均有尸检确诊的诊断。这 47 匹马中有 4 匹在尸检时神经检查正常，其余 43 匹患有神经疾病，包括马退行性脑脊髓病（EDM）、颈椎狭窄性脊髓病、创伤和其他各种疾病。1 份 CSF 样本通过 rtPCR 检测出微弱的 S. neurona 阳性，该样本来自确诊为 EDM 的马匹。其余 98 匹马的 CSF 样本通过 rtPCR 检测均为 S. neurona 阴性。
我们的研究与之前认为 S. neurona rtPCR 可能有助于 EPM 诊断的结论相矛盾，因为我们的结果表明该检测方法对 EPM 的敏感性（0%）较低。
