THE SEVERE COMBINED IMMUNODEFICIENT MOUSE AS A MODEL FOR ENCEPHALITOZOON-CUNICULI MICROSPORIDIOSIS

Microsporidia have been recently recognized as opportunistic pathogens in AIDS patients. In attempt to develop an animal model with features similar to the infections observed in the immunodeficient patients, t he adult severe combined immunodeficient mice (SCID) were administered both intraperitoneally and perorally by 2x10(7) spores of the murine isolate of E. cuniculi. The experimental inoculation caused a severe, fatal disease characterized by the dissemination of microsporidia into the host tissues. The dominant route of E. cuniculi dissemination in the SCID mice was continual direct extension from the site of inoculat ion to adjacent tissues and organs, terminating in hematogenous spread of infection in the host. The different courses of microsporidiosis i n SCID mice relative to the mode of inoculation (i.p. vs. p. o.) was o bserved. The survival time of i.p. infected SCID mice was 3 weeks - vs . 5 weeks in p.o. infected SCID mice. Experimental microsporidiosis in SCID mice should provide a useful model for studies in microsporidial pathogenesis, mechanisms of resistance, immunotherapy, and in evaluat ing potential antimicrosporidial agents.