Causes
A microscopic parasite spread through the urine of infected rabbits. Very widespread: a large proportion of rabbits are carriers. Stress and a drop in immune defences activate the disease.
Diagnosis
Blood test (serology) plus clinical signs. A definitive diagnosis is difficult because many healthy rabbits carry antibodies.
Treatment
A specific antiparasitic (fenbendazole) for several weeks, anti-inflammatories and supportive care. The sooner the neurological episode is treated, the better. Some rabbits are left with a permanent slight head tilt.
Prevention
Reduce stress, maintain good hygiene and quarantine new rabbits. It is a low-risk zoonosis, important for immunocompromised people.

