DESCRIPTIONS OF MEDICAL FUNGI

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Descriptions of Medical Fungi
Microsporum canis Bodin
Supplementary description for Microsporum canis var. distortum, a dysgonic variant of
M. canis with distinctive distorted macroconidia. Abundant growth and sporulation on
rice grains.
Microsporum canis var. distortum is a zoophilic fungus known to cause infections
in cats, dogs and other animals. It is a rare cause of tinea capitis in New Zealand,
Australia and North America. Clinical disease is similar to M. canis. Invaded hairs show
an ectothrix infection and fluoresce a bright greenish-yellow under Wood’s ultra-violet
light.
a
b
10 μm
Microsporum canis var. distortum (a) culture and (b) distorted macroconidia.
Microsporum canis var. equinum is now considered to be a genotypic synonym of
Microsporum canis (de Hoog et al. 2000). This variant of M. canis is a rare cause of
ringworm of horses. Invaded hairs show an ectothrix infection and fluoresce a bright
greenish-yellow under Wood’s ultra-violet light. Rarely infects man or other animal
species. Reported from Australia, Europe and North America.
a
b
10 μm
Microsporum canis var. equinum (a) colonies are pale buff to pale salmon with, a buff
to pinkish-buff to yellow-brown reverse. (b) Macroconidia are small, broad, irregular,
spindle-shaped, 18-60 x 5-15 µm with rough thick walls and few septa. Microconidia
are pyriform to clavate in shape, 3-9 x 1.5-3.5 µm, but are rarely produced.