Neuropathology of naturally occurring Trypanosoma evansi infection of horses.
Abstract: The clinical signs and pathology of the central nervous system in 9 horses with naturally occurring neurologic disease due to Trypanosoma evansi are described. The clinical course was 2 to 20 days; clinical signs included marked ataxia, blindness, head tilt and circling, hyperexcitability, obtundity, proprioceptive deficits, head pressing, and paddling movements. Grossly, asymmetric leukoencephalomalacia with yellowish discoloration of white matter and flattening of the gyri were observed in the brain of 7 of 9 horses. Histologically, all 9 horses had necrotizing encephalitis that was most severe in the white matter, with edema, demyelination, and lymphoplasmacytic perivascular cuffs. Mild to moderate meningitis or meningomyelitis was observed in the spinal cord of 5 of 7 horses. T. evansi was detected immunohistochemically in the perivascular spaces and neuropil of formalin-fixed, paraffin-embedded brain tissue in 8 of 9 horses.
Publication Date: 2009-03-06 PubMed ID: 19261636DOI: 10.1354/vp.46-2-251Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research focuses on analyzing the neurological symptoms and pathology in horses naturally affected by a disease caused by Trypanosoma evansi, a pathogen causing serious disorders in the central nervous system.
Clinical Signs and Course
- The study examined 9 horses with naturally occurring neurologic disorder due to Trypanosoma evansi, a parasite often resulting in severe damage to the central nervous system.
- The clinical course, or the time between the onset of the disease and its resolution, varied from 2 to 20 days.
- These horses displayed various notable clinical signs, including marked ataxia (a degenerative disease causing loss of control of body movements), blindness, head tilt and circling, hyperexcitability, obtundity (reduced alertness), proprioceptive deficits (impairments in the sense that indicates body position), and unusual movements such as head pressing and paddling.
Gross and Histological Findings
- Upon examination, 7 out of the 9 horses showed asymmetric leukoencephalomalacia, characterized by a yellowish discoloration of white matter and a flattening of the gyri (ridges of the brain), indicating serious brain damage.
- Microscopic examination revealed that all 9 horses suffered from necrotizing encephalitis, an inflammatory condition of the brain that involves tissue death. The condition had severely affected the white matter of their brains and was associated with edema (swelling), demyelination (damage to the protective layer covering nerve fibers), and lymphoplasmacytic perivascular cuffs, which are immune system-related inflammatory reactions in the brain.
- Five out of the seven horses that had their spinal cords examined exhibited mild to moderate meningitis or meningomyelitis, indicating inflammation of the membranes around the brain and spinal cord, and often suggestive of an infectious process.
Pathogen Identification
- Immunohistochemical analysis, a method to detect specific antigens in tissues, was carried out on the samples of the brain tissue of these horses, fixed in formalin and embedded in paraffin.
- The pathogen, Trypanosoma evansi, was detected in the perivascular spaces (areas surrounding blood vessels) and neuropil (a dense network of interwoven nerve fibers and their branches and synapses, along with associated glial and blood vessels) in 8 out of the 9 horses.
Presumably, this research may aid in better understanding the effects of Trypanosoma evansi on the nervous system of horses, helping in improved diagnosis and treatment of this critical disease.
Cite This Article
APA
Rodrigues A, Fighera RA, Souza TM, Schild AL, Barros CS.
(2009).
Neuropathology of naturally occurring Trypanosoma evansi infection of horses.
Vet Pathol, 46(2), 251-258.
https://doi.org/10.1354/vp.46-2-251 Publication
Researcher Affiliations
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4467 TAMU, College Station, TX 77843-4467, USA.
MeSH Terms
- Animals
- Central Nervous System Diseases / parasitology
- Central Nervous System Diseases / pathology
- Central Nervous System Diseases / veterinary
- Female
- Horse Diseases / pathology
- Horses
- Male
- Spinal Cord / pathology
- Trypanosoma / classification
- Trypanosomiasis / parasitology
- Trypanosomiasis / pathology
- Trypanosomiasis / veterinary
Citations
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