Micrograph of the fungus Microsporum canis. Microsporum canis is a dermatophyte fungus causing human skin infections. It commonly causes tinea capitus or ringworm of the scalp, mainly in children exposed to crowded conditions. The fungus is spread from infected cats or dogs by contact with the fungal spores. Microsporum canis lives in the skin of the scalp producing round scaly lesions and itchy patches of hair loss. Treatment is with antifungal drugs. Interference microscope. Magnification 160x