E. cuniculi

Question 1

What kind of parasite is e. cuniculi?

Answer 1

Microsporidium spore forming, obligate intracellular parasite

G- capsule

Question 2

How do animals become infected with e. cuniculi?

Answer 2

Transplacentally and Oral Ingestion (urine contaminated feed)

Question 3

When does e. cuniculi begin to shed in the urine?

Answer 3

1 month post infection. Shedding high at 2.5 months. No longer detectable by 90 days post infection.

Question 4

How long can e. cuniculi spores live in the environment?

Answer 4

4-6 weeks

Question 5

What cells are targeted after ingestion of spores?

Answer 5

Endothelial cells. Spores use a polar filament to inject the cells and enter.

Question 6

What creates the granulomatous response in the host?

Answer 6

After the spore enters appropriate host cells, it will mature and rupture through the cells to complete the life cycle.

Question 7

What are the organs of predilection for e. cuniculi?

Answer 7

Lens, Kidney, Brain

Question 8

What is the most common ocular sign of an e. cuniculi infection?

Answer 8

Phacoclastic uveitis

Question 9

What is the most accurate diagnostic for e. cuniculi testing in the living patient?

Answer 9

Titers using IgM, IgG, and C-reactive protein (95% positive predictive value)

Question 10

Why is just using IgM or IgG or both not as helpful?

Answer 10

Latent and active infections have the same antibody titers. IgG and IgM positives show an active infection but does not necessarily mean the infection is due to e. cuniculi.

Question 11

What is the most accurate diagnostic for e. cuniculi testing?

Answer 11

Post Mortem Histo Exam (granulomatous changes in the affected organ). Organism is not always seen.

Question 12

Why is fenbendazole the treatment of choice?

Answer 12

Anti-inflammatory action. Prevents extrusion of the polar filament. Effective at clearing the parasite from the brain. Prevents establishment of infection in exposed rabbits.

Question 13

What is the dose of fenbendazole?

Answer 13

20 mg/kg PO SID q 28 days

Question 14

What are the side effects of fenbendazole?

Answer 14

Bone marrow aplasia. Epithelial necrosis of the intestines.

Question 15

When are antibodies detectable in the blood?

Answer 15

14-28 days post infection *Varga. 3-4 weeks after infection *Quesenberry.

Question 16

When do maximum titers occur?

Answer 16

6-9 weeks post infection

Question 17

What is the earliest e. cuniculi can be detected in the organ of interest?

Answer 17

30 days

Question 18

What is thought to cause the clinical signs in an e. cuniculi infection?

Answer 18

The host immune response (chronic granulomatous inflammation)

Question 19

Rabbits infected with e. cuniculi have significantly lower levels of ______ than healthy rabbits.

Answer 19

Catecholamines

Question 20

What is IgG used for?

Answer 20

Shows exposure to e. cuniculi but not if the infection is active.

Question 21

How long does passive immunity last in newborns?

Answer 21

4 weeks

Question 22

When do young rabbits seroconvert?

Answer 22

8-10 weeks

Question 23

Can titer be correlated to clinical disease or predict outcome?

Answer 23

No, titers do not indicate organisms in the brain, are not correlated to clinical severity, and do not predict outcome. *Higher titers do correlate to more severe histo damage.

Question 24

Why is urine PCR not used more commonly for testing?

Answer 24

Intermittent shedding of the spores.

Question 25

How is e. cuniculi diagnosed in the living rabbit?

Answer 25

1. Suggestive titers. 2. Appropriate clinical signs. 3. Rule out other causes.

Question 26

What is IgM used for?

Answer 26

Signifies a recent or active infection. *Rises rapidly during a new infection and decreases in chronically infected individuals.

Question 27

What are the most common clinical signs of e. cuniculi?

Answer 27

Cataracts, Uveitis, Lens Rupture

Question 28

What is the proposed transmission for phacoclastic uveitis?

Answer 28

Vertical transmission - parasites easily infect the thin lens of developing rabbits in utero.

Question 29

How does the parasite cause phacoclastic uveitis?

Answer 29

The parasite causes lens rupture along the anterior lens capsule, leading to zonal granulomatous inflammation.

Question 30

____ is a common secondary opportunistic infection in eyes infected with e. cun.

Answer 30

Pasteurella multocida

Question 31

What are treatments for phacoclastic uveitis?

Answer 31

Topical and systemic anti-inflammatories, Enucleation, Phacoemulsification

Question 32

What is the most commonly recognized neurologic sign?

Answer 32

Vestibular disease - swaying, nystagmus, torticollis, rolling.

Question 33

What part of the brain is typically infected by e. cun?

Answer 33

Cerebrum. Leptomeninges second most.

Question 34

Central vestibular dysfunction of e. cuniculi often mimics _____.

Answer 34

Peripheral vestibular disease

Question 35

How can e. cuniculi infections be differentiated between otitis?

Answer 35

Unilateral facial spasm or hemifacial dysfunction can be seen with otitis but is NOT present in rabbits with e. cuniculi.

Question 36

What are common gross findings of kidneys affected by e. cuniculi?

Answer 36

Fibrosis, Depressed areas on the surface of the kidneys.

Question 37

What percentage of seropositive rabbits show biochemical signs of renal disease?

Answer 37

31%

Question 38

What are histopathological signs of an e. cun infected kidney?

Answer 38

Granulomatous interstitial nephritis