Microscopic observation of human hairs infected with Microsporum ferrugineum.

Human hairs infected with Microsporum ferrugineum were examined by light and scanning electron microscopy to obtain information on the parasitic form. The fungus invaded the hair filaments and developed hyphae between the hair cuticles and cortex. Spheroids of arthroconidia were frequently observed to invade the hair follicle. A mosaic sheath of massive spheroids was observed around the hair filaments. The smooth-walled arthroconidia with chitinous surfaces were single, spherical or subspherical particles of 2.0-2.5 X 2.5-3.5 microns, and 2-celled, gourd-shaped (constricted at the septum) particles of 2.5-3.0 X 5.0-7.0 microns.