Lapis ISSN 2398-2969

Abstract: Prevention and treatment of Encephalitozoon cuniculi infection in rabbits with fenbendazol


Infections with Encephalitozoon cuniculican persist without clinical signs for years. However, sporadic clinical cases do occur in rabbits of all ages, and severe outbreaks of encephalitozoonosis with a morbidity rate of 15% have been reported in young rabbits. Stunted growth, central nervous signs due to granulomatous encephalitis, eg opisthotonus, torticollis, ataxia, hyperaesthesia and nystagmus, eye lesions, eg cataract and granulomatous uveitis, and nephritis can be observed. Spores of E. cuniculiare excreted in the urine of infected rabbits and the disease is most often transmitted by the ingestion of the spores. Clinical diagnosis can be corroborated by specific serology for E cuniculi, with immunofluorescent antibody test (IFAT) or ELISA.

This paper in Veterinary Recordassesses the prophylactic and therapeutic effect of fenbendazole in rabbits with experimental infections of Encephalitozoon cuniculiand in rabbits with naturally acquired encephalitozoonoosis. Fenbendazole (20 mg/kg bodyweight daily) was administered from 7 days before until 2 or 21 days after the rabbits had been infected orally with 10*6 spores of E. cuniculi. The drug was administered as a suspension twice daily for 2 days, or as medicated pellets for 21 days. In both cases the treatment was effective in preventing establishment of the parasites (demonstrated by negative parasitic-specific serology and by the failure to isolate the parasite from brain tissue). In the naturally infected, seropositive rabbits, parasites were isolated from the brain tissue of 7 out of 9 untreated rabbits, but none from the treated 8 rabbits.

The effect of fenbendazole on established infections was also studied by treating 8 rabbits with 5 g medicated pellets daily for 4 weeks and comparing with the brains of 9 untreated rabbits. 4 out of the 9 untreated rabbits showed neurological signs consistent with encephalitozoonosis while 6 of the 8 treated rabbits died of unrelated causes with 2 euthanased after exhibiting signs of encephalitozoonosis. E. cuniculicould not, however, be isolated from the brains of the treated rabbits.

The results show that oral administration of fenbendazole is effective in preventing establishment of E. cuniculiin the rabbit and that treatment with fenbendazole may be an useful strategy to control new Encephalitozoon infections in pet and commercial rabbits. As it is known that glucocorticoids may alleviate the neurological signs of encephalitozoonosis through suppression of the granulomatous inflammation, the authors suggest that a combination of fenbendazole and glucocorticoids could be valuable.

Further Reading


Refereed papers
  • C Suter, U U Muller-Doblies, J-M Hatt, P Deplazes (2001)Prevention and treatment of Encephalitozoon cuniculiinfection in rabbits with fenbendazole. Vet Rec148, 478-480.