E. cuniculi is a protozoal parasite of rabbits which affects the nervous and urinary systems and can cause a number of clinical signs, these include but are not limited to, head tilt, hind limb paralysis or weakness, eye problems and death. It is a common parasite which is frequently sub-clinical but over 50% of animals are seropositive. E. cuniculi is zoonotic and presents a particular risk to individuals who may be immunocompromised. Published data on the efficacy of fenbendazole in the treatment and prevention of E. cuniculi in rabbits indicate that a minimum treatment period of 28 consecutive days at 20 mg/kg bodyweight is required for adequate control.