Pythiosis or otherwise known as “Swamp Cancer” is caused by Pythium insidiosum which has long been regarded as a fungus. This tropical disease is contracted after exposure to the spores which are found in stagnant water (swamps, ponds, lakes, and wet fields). Most often the spores infect damaged skin thru sores or mucosa where they flourish causing a large necrotic tumor or mass. A key feature of this mass is the production of kunkers which look like firm tan/yellow chunks that can be expressed from the tissue.
Often Pythium can resemble a summer sore or various types of equine tumors. Diagnosis is key as pythium will not respond to typical wound treatments such as antibiotics, creams, dewormers, or steroids. Diagnosis can be made thru a biopsy or blood serum testing. It needs to be treated rapidly and aggressively in order to have a chance at a cure. If left untreated, it will take over all surrounding tissue and will result in the horse needing to be euthanized.
Treatment often involves debulking the mass, antifungals, and a Pythium vaccination. Even with rapid diagnosis, this is a terrible disease and may not respond to treatment. While it may not be possible to avoid the Pythium spores, you can protect your horse by keeping them in a dry area with all wounds covered until any sores have healed.
This column is sponsored by Polk Equine, and the opinions expressed herein may not re ect those of CFAN or of its advertisers.
BIO: Dr. Katie Hennessy graduated from the University of Illinois College of Veterinary Medicine in 2008 with a degree in large animal health and equine medicine. She completed an advanced internship at The Equine Medical Center of Ocala and is currently the owner and practicing veterinarian
at Polk Equine. Her expertise ranges from small and exotic creatures to large animals, specializing in equine medicine.