Molecular detection of Sarcocystis neurona in cerebrospinal fluid from 210 horses with suspected neurologic disease

Bernardino, Pedro N.; Smith, Woutrina A.; Conrad, Patricia A.; Packham, Andrea E.; Tamez-Trevino, Eva; Barnum, Samantha; Pusterla, Nicola

doi:10.1016/j.vetpar.2021.109372

Cited by 5 publications

(16 citation statements)

References 21 publications

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“…The 2 PCR‐positive horses previously had received antiprotozoal drugs 6 . Subsequent work on the utility of rtPCR for the detection of S. neurona in equine CSF suggested this molecular tool as a promising adjunctive diagnostic method after obtaining 38 rtPCR‐positive CSF samples with a cutoff CT of 39 7 . Of the 38 rtPCR‐positive samples, 13 were positive on immunodiagnostic testing (IFAT serum:CSF ratio ≤64) and the remaining 25 were negative 7 .…”

Section: Discussionmentioning

confidence: 99%

“…Primers (each 400 nM), probes (each 80 nM) and 5 μL of DNA solution were added for a final reaction volume of 12 μL. The sequences of primers and probes used for the assay are identical to those used previously and shown in Table 1 7 . A cutoff cycle threshold (CT) of 40 was set for the rtPCR results, similar to the previous study, 7 which stated a cutoff CT of 39 but included as positive a sample with a CT value of 39.77.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, real‐time PCR (rtPCR) was proposed as a promising complementary diagnostic tool to immunodiagnostics on horses with suspected EPM 7 . This study identified 38 positive CSF samples using rtPCR from which only 13 CSF samples were positive on indirect fluorescent antibody test (IFAT) with serum:CSF ratio ≤64, leaving 25 horses possibly affected by EPM that would have been missed by traditional immunodiagnostic testing 7 . The study used 210 paired serum and CSF samples, but was limited by lack of diagnostic information.…”

Section: Introductionmentioning

confidence: 99%

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

Enriquez,

Morrow,

Graves

et al. 2023

Veterinary Internal Medicne

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BackgroundEquine 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.ObjectiveTo 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.AnimalsNinety‐nine horses with neurologic disease that underwent complete neurologic examination, CSF collection, and, if euthanized, necropsy including the central nervous system (CNS).MethodsRetrospective 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.ResultsFifty‐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 ImportanceOur 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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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Enriquez,

Morrow,

Graves

et al. 2023

Veterinary Internal Medicne

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“…The detection of S. neurona DNA in CSF is also useful but the results can vary with sensitivity and specificity of the method in clinical settings. In a retrospective study of CSF samples from 210 horses with neurological signs, by using a highly sensitive reverse transcription (RT)-PCR method, S. neurona DNA was detected in 25 horses that were negative for intrathecally derived S. neurona [isothermal titration calorimetry (ITC)] antibodies (Bernardino et al ., 2021). In 30 horses, ITC antibodies were detected but had no evidence for parasite DNA.…”

Section: Sarcocystis Neurona and Epmmentioning

confidence: 99%

“…Because of the retrospective nature of the study there was no post-mortem confirmation of EPM (Bernardino et al ., 2021). The authors speculate that detection of parasite DNA in horses without ITC antibodies might have been related to the clinical stage of EPM and whether horses were treated with antiprotozoal drugs (Bernardino et al ., 2021). Further studies are needed to explore the diagnosis by using RT-PCR.…”

Section: Sarcocystis Neurona and Epmmentioning

confidence: 99%

Sarcocystis neurona, Neospora spp. and Toxoplasma gondii infections in horses and equine protozoal myeloencephalitis (EPM): five decades of personal experience, perspectives and update

Dubey

2022

Parasitology

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Sarcocystis neurona, Neospora spp. and Toxoplasma gondii are related protozoans; they were considered the same parasite until 1970s. Two of these parasites, S. neurona and Neospora spp. are associated with a neurological syndrome in horses, called equine protozoal myeloencephalitis (EPM). The diagnosis and treatment of EPM are difficult. Most cases of EPM are related to S. neurona while only a few are due to Neospora spp. infections. There are two species of Neospora, Neospora caninum that has a wide host range and Neospora hughesi that has been found only in horses. Currently, T. gondii is not considered as a cause of EPM in horses, although it causes neurological illness in many other hosts, including humans. The present review provides an update on history, life cycle, diagnosis and treatment of these three infections in horses.

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Infectious, inflammatory, and immune diseases

2022

Large Animal Neurology

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Molecular detection of Sarcocystis neurona in cerebrospinal fluid from 210 horses with suspected neurologic disease

Cited by 5 publications

References 21 publications

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

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

Sarcocystis neurona, Neospora spp. and Toxoplasma gondii infections in horses and equine protozoal myeloencephalitis (EPM): five decades of personal experience, perspectives and update

Infectious, inflammatory, and immune diseases

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