Experimental spironucleosis (hexamitiasis) in the nude mouse as a model for immunologic and pharmacologic studies.

Experimental infection of the nude (nu/nu) mouse with the intestinal flagellate, Spironucleus (Hexamita) muris, was used as animal model for immunologic studies and for the testing of protozoa cides. The fecal discharge of cysts was shown to correlate with the immune status of the host. It was dependent on the strain, presence of the thymus (nu/nu and nu/+), and age (immunologic maturity). Four protozoacides (dimetridazole, metronidazole, tinidazole, and chlormethoxyacridylamino-diethylaminopropanol-dihydrochloride) were tested in infected mice. All lowered or suppressed the fecal discharge of cysts during treatment; however, the cysts reappeared in the feces when treatment, lasting 1-3 weeks, was terminated. It was concluded that experimental infection of the nude mouse with S muris was an excellent model for immunologic and pharmacologic studies.