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PARASITOLOGY - 2 > 12 – Equine Protozoa > Flashcards

12 – Equine Protozoa Flashcards

1
Q

Eimeria leukarti

A
  • 40% prevalence in foals
  • Non-pathogenic
    o Diarrhea rare (in young foals <6 months)
  • no treatment approved or needed
  • infects horses around the world
  • not known to be zoonotic
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2
Q

What is the life cycle of Eimeria leukarti?

A
  • Oocysts passed in feces
    o Oval or pear-shaped with thick, dark brown wall and micropyle at thinner end
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3
Q

What is the best method to diagnose Eimeria leukarti?

A
  • Recovery of oocysts by floatation
    o Very large and heavy: may not be easily recovered by routine floatation techniques
  • Postmortem: presence of typical post mortem changes and ID of parasites in mucosal scrapings or histological sections
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4
Q

Cryptosporidium parvum: pathogenesis

A
  • often asymptomatic
  • prevalence in horses in Canada: 17%
  • most common in foals
  • villous atrophy and epithelial sloughing
  • malabsorptive diarrhea
  • life threatening in immunocompromised (SCID foals)
  • *ZOONOTIC POTENTIAL
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5
Q

How do you diagnose cryptosporidium parvum in horses?

A
  • IFAT on feces
  • Acid fast stain
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6
Q

How do you treat Cryptosporidium parvum in horses?

A
  • Supportive
  • ELDU paromoycin
  • Tylosin
  • Azithromyscin
  • *environmental decontamination DIFFICULT
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7
Q

Sarcocystis fayeri

A
  • DH: dog
  • IH: horse
  • Incidental finding in muscle biopsy or histopathology
  • *rarely cause eosinophilic myositis
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8
Q

Equine Protozoal Myeloencephalitis (EPM) is caused by

A
  • Sarcocystis neruona: most common
  • Neospora hughesi
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9
Q

What is the epidemiology of EPM?

A
  • Only in NA and SA
  • Seroprevalence
  • Young (<5 years) and old (>13 years)
  • Thoroughbreds, standardbreds, quarter horses
  • *usually sporadic, and only 1 horse/farm
  • *stress trigger (heavy exercise, transport, injury, surgery, birth, lactation)
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10
Q

Who is the DH for Sarcocystis neurona?

A
  • Opossum
  • *none in Canada
  • Serology in states is variable
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11
Q

Who are the IH for Sarcocystis neurona?

A
  • Skunks
  • Raccoons
  • Armadillos
  • Cats
  • Birds
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12
Q

What is a horse for Sarcocystis neurona?

A
  • Aberrant IH
    o Sarcocysts seldom develop
  • Pathology is associated with merozoites (asexual reproduction)
  • *vertical transmission considered rare
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13
Q

What is the lifecycle of Sarcocystis neurona?

A
  • DH release sporocysts into environment through its feces
  • Sporocysts ingested by IH and release sporozoites which invade intestinal mucosa and blood vessels
  • Asexual reproduction (merogony) and merozoites enter muscle cells and form sarcocysts
  • IH host dies, and DH ingests infected muscle
  • Sexual reproduction (gametogony) in DH SI to produce oocysts
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14
Q

Neospora hughesi DH and IH?

A
  • DH: unknown (wild canid)
  • IH: wildlife?
  • Horses=true IH=develops tissue cysts
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15
Q

Horses and Neospora hughesi

A
  • Tissue cysts with bradyzoites associated with pathology
  • *TRANSPLACENTAL transmission important
    o Occurs in MULTIPLE pregnancies
  • Only 1/10 positive horses develop EPM
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16
Q

How do you diagnose EPM in horses?

A
  • Can be asymptomatic, and highly variable
    o Dysphagia
    o Lameness
    o Seizures
    o Muscle wasting
    o Ataxia
17
Q

What is the most consistent diagnosis for EPM in horses?

A
  • Asymmetric gait and focal muscle atrophy
18
Q

What is the definitive post mortem diagnosis for EPM in horses?

A
  • IHC or PCR on CNS
19
Q

What are the 3 steps to diagnosis EPM in horse?

A
  1. Neurological exam
  2. Rule out other causes (non febrile, no pain)
  3. **Definitive antemortem diagnosis is a high CSF: serum Ab ratio
    a. Seropositivity more useful to diagnosis EPM
20
Q

How do you treat EPM in horses?

A
  • ALWAYS TREAT (10x more likely to improve)
  • Sulfadiazine and pyrimethamine (coccidiostatic)
  • Ponazuril, diclazuril (coccidiocidal)=BETTER
  • Duration 6-8 weeks (longer if still improving)
  • May relapse
  • NSAIDs
  • *prevent contamination of horse feed and water
  • Feed prophylaxis in highly endemic farms? Leading to resistance
21
Q

What causes Equine piroplasmosis? (3)

A
  • Babesia caballi
  • Theileria equi: MORE PATHOGENIC
  • T. haneyi
  • *many ticks species are the DH
22
Q

Equine piroplasmosis

A
  • Foreign animal disease in Canada
    o Reportable disease (CFIA)
  • Endemic in various areas (tropical Africa, middle east, Asia, central and south America, Caribbean, Europe)
23
Q

What is the Lifecyle of Haemosporidia?

A
  • DH: tick
    o Sexual reproduction in gut
    o Sporogony in salivary glands
  • IH: mammal
    o Asexual reproduction in erythrocytes (babesia) (WBC: Theileria)
  • *can get iatrogenic transmission
24
Q

What is the pathology of equine piroplasmosis?

A
  • May be asymptomatic, but INFECTIVE
  • Mild weight loss/fever to anemia, splenomegaly, hepatomegaly, abortions, death
  • 50% mortality
  • May be acute=horses found dead
25
Q

Economic and animal health of equine piroplasmosis

A
  • Loss of animals
  • Reduced sport performance
  • Restrictions on internal travel/trade
  • Cost of treatment, quarantine, testing
26
Q

Human-associated transmission

A
  • If coming from endemic country=require negative test
  • To transport horse from Canada to US: only need 30d health/negative EIA (equine influenza anemia)
  • If travelling for sport: NO testing required (known positives can enter the country)
  • Horses traveling to endemic areas are NOT tested upon re-entry
27
Q

How do you diagnose equine piroplasmosis?

A
  • Trophozoites or merozoites on peripheral blood smear (ear nick): not as good
  • History, clinical signs, serology, PCR
    o CFIA uses IFA and ELISA
28
Q

How do you prevent equine piroplasmosis?

A
  • Tick control
  • Movement controls
  • Avoid illegal doping (at least use a clean needle)
29
Q

Equine piroplasmosis management in USA

A
  • Quarantine and enroll in treatment program
    o High doses of imidocarbdipriopionate until seronegative
  • OR life long quarantine (costly, horse welfare)
  • OR euthanize
30
Q

Equine piroplasmosis management in Canada: treatment under consideration

A
  • Humane euthanasia ($ compensation from government: but does not cover all of it)
  • Surveillance and tracing
  • Strict quarantine to prevent spread

PARASITOLOGY - 2 (13 decks)

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