Encephalitozoon cuniculi
What is it?
E. cuniculi is a microscopic parasite that many rabbits carry without showing signs. It spreads through urine and from mother to babies. In some rabbits it causes damage to the brain, kidneys, or eyes, sometimes years after infection.
What signs should I watch for?
Signs to watch for include head tilt; rolling, circling, or poor balance; hind-leg weakness or paralysis; urinary incontinence or urine scald; and cataracts or inflammation inside the eye.
How is it diagnosed and treated?
Diagnosis is based on signs plus blood tests, though a positive test only shows exposure. Treatment involves antiparasitic medication, anti-inflammatory and supportive care, and nursing care such as padded housing and hand-feeding if needed.
Can it be prevented, and what's the outlook?
- Many rabbits improve and adapt well, even with a lasting head tilt.
- Good hygiene and testing new rabbits help limit spread.
Reviewed by the Adler Veterinary Hospital veterinary team, October 2026.
Many rabbits carry it silently
Who's at risk:
Head tilt, rolling or circling, hind-leg weakness
Main signs:
See a vet within a day or two
Urgency:
When to call a vet right away
- Rolling, circling, or poor balance
- Hind-leg weakness or paralysis
Not sure whether it can wait? Call us anyway. Our team can help you decide.
Source:
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