Computer illustration of Microsporum canis fungus, a common cause of ringworm of the scalp (tinea capitus), showing fungal threads of the vegetative mycelium (hyphae), with spore-producing fruiting bodies (macroconidia). This is a dermatophyte fungus that causes skin infections. It is spread to humans from an infected cat or dog by contact with the fungal spores. Microsporum canis inhabits the skin of the scalp giving rise to round, scaly lesions and producing itchy patches of hair loss, mainly in children, and sometimes in adult women. Treatment is with antifungal drugs. The illustration shows the microscopic morphology of the fungus. M. canis has septate hyphae with numerous long spindle-shaped, rough and thick-walled macroconidia. A few microconidia are also seen formed along the hyphae.