Circling syndrome and inner ear disease in mice infected intraperitoneally or intravenously with Coccidioides immitis spherule-endospore phase cultures.

Infection was studied in mice with varying doses of spherule-endospore phase cultures of Coccidioides immitis, administered intraperitoneally, intravenously and intranasally. Stain 46 was compared with strain Silveira. The first of these is relatively avirulent in the mycelial phase, the second, rather virulent. Animals were observed for acute death and for circling. Gross and microscopic pathology was studied in mice sacrificed at appropriate intervals after infection. Numbers of fungi were assayed in spleen, lung, kidney, liver, blood, brain, and ear tissue. Strain 46 endospores administered intraperitoneally in doses from 9 X 10(6) to 2.5 X 10(7) produced a high incidence of 'circling syndrome' ataxia attributable to inner ear disease.