Estimates of C. immitis infection by skin test reactivity in an endemic community.

Abstract

This report is a comparison of 2 delayed hypersensitivity skin test reagents, coccidioidin and Spherulin, avaliable for detection of prior infection by C. immitis. Coccidioidin proved to be a somewhat more sensitive reagent (33.4% positive vs. 29.6% for Spherulin). This difference persisted in the subjects when grouped by age, sex, exposure history, or history of coccidioidomycosis. Skin test reactivity to both reagents declined with age. Independent of exposure history, coccidiodin detected 7.3% of the subjects who were not detected by Spherulin; Spherulin detected prior infection in only 3.5% of the subjects not detected by coccidioidin. These results differ from those of previously reported studies.