An unusual isolate ofCoccidioides immitisfrom the Los Banos area of California

An atypical form of Coccidioides immitis has been isolated from the Los Banos area of California where several anthropology students had been infected. Three cultures were recovered from soil and all produced arthrospores in a cluster of hyphal branches which formed acute angles with the main branch. This was compared with the more characteristic strains in which arthrospore-bearing hyphae developed at right angles to the main branch and were distributed evenly throughout the colony.Because of the variations which occur in colour and texture of colonies these properties are inadequate for the identification of C. immitis. Infection of experimental animals with demonstrable endosporulating spherules is the most reliable basis for identification of C. immitis.