-
What is the pathological process that involves inflammation and necrosis of vascular walls?
Causes? 5
Vasculitis
- Usually 2' to:
- Infection
- Toxin
- Immune response
- Neoplasia
- Idiopathic
-
Hallmark of vasculitis?
Predominant involvement of small vessels in the skin
-
C/S associated with vasculitis? 9
- Edema- Peripheral/Limb
- Hyperemia
- Echymosis/petechia
- Ulceration of MM
- Hemorrhage
- Vascular necrosis in any organ (lameness, colic, dyspnea)
- Fever
- Anorexia
- Lethargy
-
Sequela to vasculitis? 4
- Cellulitis
- Thrombophlebitis (occluded jugular v)
- Laminitis
- Pneumonia
-
4 common causes of vasculitis?
- Idiopathic
- Equine viral arteritis
- Equine purpura hemorrhagica
- Equine infectious anemia
-
What is a non-contagious disease that is sequela to systemic diseases like Strangles?
Purpura hemorrhagica (EPH)
-
Signalment often associated with EPH?
- Young to middle aged horses
- 2-4 weeks following respiratory infection
- (not neonates, up to ~8yrs old)
-
Expected findings on MDB with purpura hemorrhagica? 5
- Anemia
- Neutrophilia
- Hyperproteinemia
- Hyperfibrinogenemia
- Elevated muscle enzymes (CK, AST)
- (thrombocytopenia rare)
-
Classic findings on skin biopsy with purpura hemorrhagica? 3
- Leukoclastic vasculitis w/necrotic vessels
- Complexes of IgM/IgA (type 3 hypersensitivity)
- Strep M protein
-
EPH Tx? 4
- Tx primary condition
- Penicillin
- Hydrotherapy + Distal limb bandages
- *steroids* 2-4wk minimum
-
Which Vx is associated with EPH formation?
How can this be avoided?
Strep. equi (strangles)
Titers >1:1600 = poor candidate for the Vx, Greater risk for causing EPH
-
which infectious disease causes vasculitis and abortions?
equine viral arteritis
-
Mechanism of transmission for EVA?
- Venereal
- Respiratory secretions
- Urine
- Fetal fluids
- NOT arthropod borne
-
C/S's in a horse with EVA? 6
How long after infection will signs appear?
- Fever/Lethargy/norexia
- Edema/Vasculitis
- Stiffness
- Rhinorrhea
- "Pink eye"
- Abortion
1-10days post infection
-
How far into gestation will mares abort if infected with EVA?
Will mare remain carrier for life?
Abort 3-10 months
- Mares NOT carrier for life
- *stallion remains carrier for life*
Mare may show no signs while shedding and then fully recovers w/long natural immunity
-
Target organ with EVA?
- Blood vessels
- (=Fibrinoid necrosis of tunica media w/perivascular lymphocytic infiltrates; thrombi)
-
why is castration of stallion curative for EVA?
- Testosterone dependent disease
- Virus resides in ejaculate
- (also can not become infected until after puberty - testosterone)
-
What happens to foal born to mother infected with EVA (assuming she doesn't abort)?
Interstitial pneumonia in the newborn
-
Dx of EVA?
4 fold increase in titer
Serum + Stallions then get PCR/culture/viral isolation
-
EVA Vx?
Problem?
Benefit?
Yes
- Can't distinguish Vx from infection
- Can prevent infection in males vaccinated before puberty
-
how is equine infectious anemia transmitted? 4
- Tabanid insects (horseflies, deer flies)
- Blood transmission
- Fomites (re-use of needles, etc)
- Verticle (in utero/colostrum)
-
In the acute stage of EIA there is a burst of viremia that leads to what C/S's? 4
- *fever*
- Malaise
- *thrombocytopenia*(evident before anemia?)
- Petechia/ecchymosis
-
Findings with chronic EIA?
- Anemia
- Sick horses "swampers" = acute or chronic Episodes
-
Would horse in the inapparent stage of EIA test + for the virus?
- No
- No viremia during inapparent stage
-
What is a risk and possible cause of death in any horse exhibiting signs of EIA?
- DIC
- (virus attacks endothelium - vasculitis - death)
-
Gold standard Dx test for EIA?
Coggin's Test (USDA approved test) = agar gel immunodiffusion for p26 Ag
-
Since the coggin's test requires 24 hours to complete, what is another option for testing EIA?
- ELISA = serology for detection of transmembrane glycoprotein p26 and gp45
- (all positives must be confirmed w/coggins)
-
EIA is a reportable disease. What happens to EIA positive horses?
- Remove from population (euthanasia)
- OR
- Brand/tattoo and separate at least 200yd from other horses
-
How is Equine piroplasmosis transmitted?
Ixodes ticks carry protozoa - theileria equi and babesia caballi
-
What does equine piroplasmosis cause?
How common is this disease in the US?
Will infected horses be carriers for life?
Acute hemolytic anemia (intravascular)
Rare
Seropositive for life
-
How old are horses when infected with piroplasmosis?
- <1 yr (naive horse intro to endemic herd)
- Neonates (In utero, poor prognosis)
-
C/S for Piroplamasmosis...
Carrier state:
Acute state:
- Carrier:
- No signs and low parasitemia
- Acute:
- Fever
- Malaise
- Incr. RR/HR
- Edema
- Death
-
Dx for Piroplasmosis?
- Blood smear + C/S (☩ = merozoites)
- *Competitive ELISA* (TOC)PCR (early & carrier)
- *Reportable*
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