Equine Protozoal Myeloencephalitis.
Abstract: Advances in the understanding of equine protozoal myeloencephalitis (EPM) are reviewed. It is now apparent that EPM can be caused by either of 2 related protozoan parasites, Sarcocystis neurona and Neospora hughesi, although S neurona is the most common etiologic pathogen. Horses are commonly infected, but clinical disease occurs only infrequently; the factors influencing disease occurrence are not well understood. Epidemiologic studies have identified risk factors for the development of EPM, including the presence of opossums and prior stressful health-related events. Attempts to reproduce EPM experimentally have reliably induced antibody responses in challenged horses, but have not consistently produced neurologic disease. Diagnosis of EPM has improved by detecting intrathecal antibody production against the parasite. Sulfadiazine/pyrimethamine (ReBalance) and the triazine compounds diclazuril (Protazil) and ponazuril (Marquis) are effective anticoccidial drugs that are now available as FDA-approved treatments for EPM.
Copyright © 2022 Elsevier Inc. All rights reserved.
Publication Date: 2022-07-07 PubMed ID: 35810151DOI: 10.1016/j.cveq.2022.05.003Google Scholar: Lookup
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- Journal Article
- Review
- Clinical Pathology
- Clinical Signs
- Clinical Symptoms
- Diagnosis
- Disease
- Disease Diagnosis
- Disease Treatment
- Epidemiology
- Equine Health
- Equine Protozoal Myeloencephalitis
- Horses
- Infection
- Infectious Disease
- Lameness
- Neurological Diseases
- Neurology
- Parasites
- Sarcocystis
- Serological Surveys
- Veterinary Care
- Veterinary Medicine
Summary
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This research article explores Equine protozoal myeloencephalitis (EPM), a common neurological disease seen in horses in the Americas, caused by the agent Sarcocystis neurona. The study reviews EPM’s lifecycle, its diagnosis, symptoms, and the treatment methods.
Disease Overview
- The article first provides an overview of Equine protozoal myeloencephalitis (EPM), highlighting it as a prevalent neurological disease among horses in the Americas. It comes with variable severity, from mild lameness to severe cases that can lead to sudden immobility or ‘recumbency’.
Signs and Symptoms of EPM
- Specifically, horses afflicted with EPM commonly show gait abnormalities, which likely stem from the disease’s neurological effects. However, these animals might also exhibit signs indicative of brain disease.
- The manifestations generally progress over time, meaning symptoms can gradually become more severe if left untreated.
Causative Agent Sarcocystis neurona
- The study notes that Sarcocystis neurona, a type of protozoa, has been identified as the causative agent for EPM due to its isolation from affected horses.
- Exposure is fairly common among horses in the United States, with serologic studies indicating that about half of the horse population in the country has come into contact with S. neurona at some point.
Diagnosis and Treatment
- EPM is treatable, and this research paper discusses the various diagnostic methods and treatment options. However, it also indicates that outcomes are frequently halting, with many animals not making a complete recovery even after receiving antimicrobial treatment.
- Furthermore, this study sheds light on the lifecycle of S. neurona, providing a deeper understanding of the pathogenesis of the disease. Understanding this cycle is critical for devising effective preventive and control strategies.
Conclusion
- The paper offers a comprehensive review of the literature on diagnosis, clinical characteristics, treatment, and new information on S. neurona’s life cycle in the context of EPM. This is essential in providing a thorough understanding of EPM, its causes, manifestation, treatment, and prevention strategies.
Cite This Article
APA
MacKay RJ, Howe DK.
(2022).
Equine Protozoal Myeloencephalitis.
Vet Clin North Am Equine Pract, 38(2), 249-268.
https://doi.org/10.1016/j.cveq.2022.05.003 Publication
Researcher Affiliations
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, 2015 Southwest 16th Avenue, PO Box 100136, Gainesville, FL 32610-0125, USA.
- Department of Veterinary Science, M.H. Gluck Equine Research Center, University of Kentucky, 108 Gluck Equine Research Center, Lexington, KY 40546-0099, USA. Electronic address: dkhowe2@uky.edu.
MeSH Terms
- Animals
- Coccidiosis / drug therapy
- Coccidiosis / epidemiology
- Coccidiosis / veterinary
- Encephalomyelitis / drug therapy
- Encephalomyelitis / veterinary
- Horse Diseases / drug therapy
- Horse Diseases / parasitology
- Horses
- Sarcocystis
- Sarcocystosis / drug therapy
- Sarcocystosis / veterinary
Citations
This article has been cited 2 times.- Countrymann K, Ruby R, Miller AD. A retrospective study of 171 cases of equine meningoencephalomyelitis in the United States, 1996-2023. J Vet Diagn Invest 2026 Jan;38(1):100-111.
- Tuniyazi M, Tang R, Hu X, Fu Y, Zhang N. Carbonate buffer mixture and fecal microbiota transplantation hold promising therapeutic effects on oligofructose-induced diarrhea in horses. Front Vet Sci 2024;11:1388227.
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