Equine sporotrichosis is a cutaneous and subcutaneous fungal skin infection in horses, caused by Sporothrix schenckii. S. schenckii is a type of dimorphic fungus that is found in soil, plants, and decaying vegetation worldwide. It is particularly common in tropical regions and during periods of high humidity where temperatures promote fungal growth.

Transmission
Horses become infected with S. schenckii usually through open skin wounds that become contaminated with soil or plant material containing the organism.