In recent experimental investigations* the feet of human volunteers deliberately were subjected to massive exposures to pathogenic fungi (Trichophyton mentagrophytes, T. rubrum, and Epidermophyton floccosum). It may be recalled here that in these investigations, despite such overwhelming exposures, we were unable to produce clinical fungous disease of the feet in subjects with mycologically and clinically healthy feet, and that no change in the character or intensity of the eruption occurred in subjects with fungous disease of the feet † who were exposed to a different species of fungi from that causing their disease.
Even though the deliberate exposures to fungi did not produce clinical changes, they appeared to be adequate to produce at least temporary establishment of the fungi on the feet of some of the volunteers, as suggested by positive microscopic fungous examinations in 56% of previously fungusfree feet, and as shown by recovery
ROGACHEFSKY H, ROSENTHAL SA, LITT JZ, BAER RL, Furnari D. Trichophytin Reaction After Exposure to Dermatophytes. AMA Arch Derm. 1956;74(6):606–609. doi:10.1001/archderm.1956.01550120026005