Diagnosis of experimental encephalitozoonosis in rabbits by complement fixation.

A complement-fixation (CF) test has been developed for detection of experimental encephalitozoonosis in rabbits. The antigen consisted of disrupted homogenates of Encephalitozoon cuniculi spores grown in and released from rabbit choroid plexus tissue culture cells. The test was sensitive and capable of detecting experimental encephalitozoonosis in rabbits as early as 15 days after intracerebral infection. The test was specific for infected animals, and no cross-reactivity was demonstrated between E. cuniculi antigen and Nosema apis, Trypanosoma congolese, Trypanosoma cruzi, rabbit liver powder, rabbit brain powder, and rabbit choroid plexus cell culture. Sera from rabbits infected with Toxoplasma gondii, Eimeria stiedai, and Eimeria perforans did not exhibit antibodies to E. cuniculi. No CF-inhibition activity was detected.