On this page we intend to periodically provide advice on diagnostics involving the serologic tests that we perform, in a question and answer format.

Encephalitozoon cuniculi infection in rabbits

 Q. Are the signs exhibited by the rabbit consistent with encephalitozoonosis?

 A. The following signs have been significantly correlated with high levels of antibody to E. cuniculi in rabbits: head tilt, nystagmus, rolling, seizures, intraocular opacity, lens rupture and uveitis.


 Q. What does a positive antibody test for E. cuniculi mean?

A. The rabbit has been infected with and made antibodies to E. cuniculi. Since infection is considered to be persistent, the rabbit probably harbors the organism in the brain and kidneys. If the infection is latent and suppressed by the rabbit’s immune system, antibody levels may be low to moderate. High levels of antibody usually indicate active infection.


Q. What if the rabbit has head tilt and the E. cuniculi antibody test is negative?

A. The head tilt could be due to bacterial infection of the middle/inner ear, cerebral larva migrans or cerebral vascular accident. Alternatively, the rabbit could be immunocompromised.


Q. What should be done if the test is positive and the rabbit appears healthy?

A. Treatment with benzimidizoles may be helpful but could induce undesirable side effects. The owner should be alerted for early signs of disease and treatment initiated if any changes in behavior consistent with neurologic disease occurs.


Q. If the rabbit is treated for encephalitozoonosis, when will the antibody test become negative?

A. Repeated testing of individual rabbits positive for E. cuniculi antibodies has shown that levels remain high for months. Rarely are antibody levels reduced in rabbits treated with benzimidazoles.


Q. How contagious is E. cuniculi?

A. The spores are excreted in the urine of infected rabbits. However, transmission occurs shortly after initial infection and is considered to be brief. Oftentimes, one rabbit is antibody-positive, whereas a companion rabbit is negative. Currently, there is no test for spores in the urine.