Term
| Equine protozoal myeloencephalitis (EPM) |
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Definition
-Sarcocystis neurona (95%)
-Neospora hughesi
-dz incidence=1%
-common dz in N and S America, Eastern states more cases, most common in regions with moderate temp
-<5 yr old adults at higher risk |
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Term
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Definition
-performance in horses:TB and WB > risk than QH
-increased incidence in fall and lowest incidence in winter
-increased incidence if opposums seen
-decreased risk in rodent-proof containerd
-inc risk if previous EPM cases found on farm
-incr incidence if horse previously stressed |
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Term
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Definition
-S. neurona, S. hughesi
-Natural 2 host cycle
-30-60% horses exposed and seroconvert
-most horses d/n develop CNS signs
-S. neurona: horses acquire the infection from opossum fecal contamination of pastures and horses feed
-some horses-parasite invades the CNS
-stress often precedes dz
-focal, multifocal, or diffuse, asymmetric nonsuppurative inflammatory lesions in brain and particularly in spinal cord
-focal discoloration
-infected nerve cell bodies-> cell death, inflammation, edema |
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Term
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Definition
-dependant on area of CNS where ingestion occurs
-80% of cases involve spinal cord only
-Clinical signs are usually asymmetrical
-cerebral signs include: depression, changes in mentation, and seizures
-acute or insidious
-rate of progression variable
-highly variable
-asymmetric ataxia, weakness, CP deficits, muscle atrophy
-obscure lameness
-behavioral changes (head tossing, difficulty maintaining a lead)
-CN deficits, seizures, narcolepsy-like activity, urinary incontinence |
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Term
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Definition
-depression-RAS
-Dysphagia-CN IX and X
-Vestibular disorders-CN VII (head tilt, circling/leaning, vestibular ataxia)
-Facial paralysis-CN VII (ear/eyelid droop/paresis, deviated muzzle)
-Gait deficits-rubrospinal tracts, UMN signs, conscious proprioception deficits |
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Term
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Definition
-gait deficits-UMN and LMN signs: sensory ataxia/weakness, assymetric, may be vague-lameness, toe drag, circumduction, knuckling, short stride
-muscle atrophy-LMN signs
-bladder atony |
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Term
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Definition
-clinical signs: recognition of a multifocal asymmetric dz, use your clinical judgement
-CSF tap: WBC, RBC, CK, protein, may be normal
-three methods are used to detect antibodies to EPM in sera or in CSF samples: 1. western blot (less antigen specific, false positive, positive tests indicates exposure; CSF: serum abs, positive test d/n always indicate infx of the nervous tissue, healthy horses-20% will have a positive test result) 2. IFAT test 3, SAF2/3/4 ELISA |
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Term
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Definition
-immunofluorescent antibody test
-provides a numerical titer for serum or CSF fluid
-provides a likelihood that horse has EPM based on titer
-Appears to be more accurate that Western blod
-distinguishes: S. neurona and N. hughesi |
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Term
| EPM Dx: Antemortem tests (difficult) |
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Definition
| -Antemortem tests (S. neurona)-Western Blot, IFA, SAG2/3/4 ELISA |
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Term
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Definition
1. clinical signs-must have neuro diseases
2. Serum IFAT test: can have false negative results (10% of cases) so best to combine with CSF
3. CSF tap: cytology and IFAT
4. tx for EPM until test results returned |
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Term
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Definition
-Banamine
-Ponazuril (Marquis)
-Sulfadiazine and Pyrimethamine |
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Term
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Definition
-varies with how quicklydx
-if is a delay of several weeks prognosis often poor
-early dx and tx results in improvement of clinical signs in 75% horses
-RELAPSES are common |
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Term
| Equine Herpesvirus-1 Myeloecncephalopathy |
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Definition
-Epidemiology: sporadic, adult horses
-EHV-1: respiratory dz, abortion
-Neuro dz can precede or follow resp or abortive forms but d/n always |
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Term
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Definition
-herpesviridae: alpha herpes
-EHV1
-EHV3 (urogenital dz)
-EHV4 (resp virus)
-Gamma herpesvirus:
-EHV2
-EHV5 |
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Term
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Definition
-respiratory
-abortion (>50%)*3rd trimester>>>others
-neonatal death
-neurologic (10%)
-EHV1 endemic in equine population (prevalence varies with geographic location |
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Term
| Risk factors for neurologic form |
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Definition
-latent state
-stress
-high fever on day 3
-pregnant mares
-any age
-season of year (fall, winter, spring)
-transmission: inhalation, contact, ingestion |
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Term
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Definition
-adherence-nasopharyngeal epithelium, MALT
-replication-resp. epithelium, lymphoid tissue
-systemic circulation (viremia)-T lymphocytes, duration 21 d
-endotheliotrophic-vasculitis, thrombosis, hemorrhages, ischemia, infarcts
-viremia precedes (100%)-abortion; neuro dz (white matter> gray matter; brainstem) |
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Term
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Definition
-brain: multifocal lymphocytic vasculitis, hemorrhages, ischemia, necrosis
-spinal cord: multifocal lymphocytic vasculitis, hemorrhages, axonal degeneration
-other organs with vasculitis: lungs, kidneys |
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Term
| Severity of disease: EHV1 |
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Definition
-Horses: age-older horses (neuro), health status, immune system
-EHV1 genetic diversity |
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Term
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Definition
-Xanthochromic (yellow)
-Nucleated cell count (1-19/ uL)
-normal to mononuclear pleocytosis (lymphocytes0
-increased protein (>100-400 mg/dL)
-majority >200 mg/dl |
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Term
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Definition
-CSF analysis
-VI
-Serology
-Molecular (PCR)-qualitative, buffy coat, nasal/nasopharyngeal |
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Term
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Definition
-clinically affected horses
-blood on EDTA and nasal swab
-NO asymptomatic horses, except exposed horses |
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Term
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Definition
-supportive
-prevent complications (i.e. decubital ulcers, neurologic-penile paralysis, pressure neuropathies, ischemic myelomalacia, cystitis, specific: antivirals, antiinflamm, antiox, neuroprotectants=Give acyclovir IV, give vacyclovir oral |
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Term
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Definition
-NO vax prevents against neural form of EHV-1
-ideal vax:
-prevents
-protects against infection
-stimulates immune system
-effective during viral intracellular cycle
-no interference with maternal antibodies |
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Term
| **KNOW** During an outbreak there are three main goals |
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Definition
1. early diagnosis (PCR)
2. prevent dissemination
3. therapeutic management
**Isolate infected horses!! |
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