Sporotrichosis is a worldwide disease caused by Sporothrix schenckii, a yeast-like fungus present on vegetation, particularly on the thorns of roses and on plants that carry sharp spicules, or needlelike projections.
A draining sore develops at the site of a puncture wound. This usually occurs on the leg but sometimes on the upper body. Nodules appear beneath the skin along the course of lymphatics. The nodules ulcerate, discharge pus, crust over, and heal slowly.
The diagnosis is made by taking a sample of wound discharge for fungus culture, or a specimen of infected tissue for fluorescent antibody testing. The disease at times resembles ulcerative lymphangitis. The frequent application of warm packs is highly beneficial, as the fungus is particularly sensitive to heat. Sporotrichosis often responds to oral iodine therapy when given for several weeks. To prevent relapse, continue treatment 4 weeks beyond healing. In horses that relapse or do not respond to the above, various drugs used to treat human fungus diseases can be tried under close veterinary supervision. Sporotrichosis can be transmitted to people. Use disposable rubber gloves and hygienic techniques when handling infected material.