Infectious disease · Updated 2026-09-29
E. cuniculi in rabbits
A common parasite that can lie dormant, then cause head tilt, balance loss, kidney disease or eye problems.
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Signs to watch for
- Head tilt
- Rolling or loss of balance
- Flicking eyes
- Weakness in the back legs
- Increased thirst
- White mass in the eye
Causes and risk factors
The spores spread in urine; many rabbits carry the parasite without ever becoming ill.
How veterinarians diagnose it
Blood tests and ruling out ear infection and other causes of head tilt.
Treatment and management
Antiparasitic medication, anti-inflammatories, supportive nursing and help with eating if needed.
Prevention
Hygiene, testing or treating new rabbits before introduction, and vet-advised preventive courses.
Outlook
Many rabbits improve and adapt well, even with a lasting head tilt.
Common questions
- What are the signs of e. cuniculi in rabbits?
- Head tilt; Rolling or loss of balance; Flicking eyes; Weakness in the back legs; Increased thirst; White mass in the eye.
- What causes e. cuniculi in rabbits?
- The spores spread in urine; many rabbits carry the parasite without ever becoming ill.
- How is e. cuniculi in rabbits diagnosed?
- Blood tests and ruling out ear infection and other causes of head tilt.
- How is e. cuniculi in rabbits treated?
- Antiparasitic medication, anti-inflammatories, supportive nursing and help with eating if needed.
- Can e. cuniculi in rabbits be prevented?
- Hygiene, testing or treating new rabbits before introduction, and vet-advised preventive courses.
- When should I contact a veterinarian?
- Sudden head tilt or rolling needs same-day exotic-vet care; keep the rabbit in a padded, low enclosure.
Preparing for a e. cuniculi in rabbits consultation
- Record when these signs began and how they changed: Head tilt; Rolling or loss of balance; Flicking eyes. Record appetite, water intake, toileting and any medicines or supplements.
- The listed urgency is urgent; worsening breathing, collapse, seizures or severe pain can make any situation an emergency. Ask the clinic rather than relying only on this category.
- Ask what else could explain the signs, which tests would change the plan and how discomfort will be managed. Symptoms alone cannot confirm this condition.
- Before going home, agree what to monitor, when to recheck and which signs mean calling sooner. Follow the individual treatment plan; do not copy another pet's prescription.
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Sources on this topic
Pages on this specific subject from recognised organisations. They are cited for further reading and do not mean the organisation has reviewed this page.
- E. cuniculi in Rabbits — PDSA
- Rabbits and E. cuniculi (Encephalitozoon cuniculi) — Rabbit Welfare Association & Fund
- Encephalitozoon cuniculi in rabbits — Royal Veterinary College
Guidance libraries and further reading
These organisations publish relevant guidance. Their links are further reading, not evidence that they have reviewed this page.