Athlete's foot fungus. Coloured scanning electron micrograph (SEM) of a fungus that causes athlete's foot on a skin cell from a human foot. The fungus usually grows between the toes, but may spread to the bottom and sides of the foot. The spores can lie dormant for long periods, until conditions are favourable for germination. Treatment involves keeping the infected area dry and using an anti-fungal powder. Magnification: x1200 when printed 10 centimetres wide.